Factory
In Manufacturing AUTOMATION’s 2009 readership survey, an overwhelming majority of readers said they were planning to buy safety products in the upcoming year. Due to this strong interest, we invited six industry experts to our first ever machine safety round table at our office in Aurora, Ont., in September. The discussion covered several topics, from standards and productivity issues to the legal ramifications of non-compliance. With the current economic challenges affecting manufacturers, many participants were concerned people were putting safety on the back burner to concentrate on short-term goals. Each invitee — some coming with a legal perspective, and others with expertise in product development or system integration — brought their own experiences to the table in a lively two-hour discussion. In our online coverage, we have exclusive video clips on each of the topics of discussion, located on each topic page. To watch all the video in one go, browse our video gallery. Jump to the topic of your choice: • Page 1: INTRODUCTION • Page 2: STANDARDS & HARMONIZATION • Page 3: RESPONSIBILITY & LIABILITY • Page 4: PRODUCTIVITY STANDARDS & HARMONIZATION Canadian companies use CSA and ISO standards — but they also use ANSI, ASME and EN, among others, and even internally developed standards. This multitude of standards can create an environment of confusion and anxiety, so the first topic of discussion was harmonization, the process of developing an agreed-upon global standard for machine safety and guarding. Walter Veugen from Veugen Integrated Technologies Ltd., a system integrator specializing in press safety controls and other machine control systems, talked about his experiences on standard committees. He and round-table participant Jim Grube, product specialist from Siemens Canada, had just spent the last 2½ years participating on the CSA Z142 power press standard. Veugen also spent three years participating on the U.S.’s ANSI B11.1, B11.2 and B11.3 power press standard, “and it was the first one in the group of ANSI standards to address harmonization. That standard started about four years ago; three-quarters of the way through, we approached CSA to ask whether they would be able to open the power press standard so that the technology new to industry would be addressed in Canada as well as the U.S. We were very vocal on harmonization. … If we have our way, I think within the next three to four years, you’re going to see harmony within Canada, the U.S. and Europe for safety circuit requirements.” VIDEO: Our experts examine current safety standards and the push toward harmonization: Calvin Wallace, a sales manager with Beckhoff Canada, agrees that progress is being made. “I know CSA is working very hard to harmonize its standards, and every year it’s getting easier and easier for Canadian manufacturers and machine builders. Most of the standards are being adopted from the U.S. and Europe. For sure, harmonization has started, and I think it’s got some momentum.” Grube believes that harmonizing certain standards — building standards, for instance — will be more difficult, “but machinery, typically, whether you have a robot here or in Germany, all have the same issues.” Allen Rutherford, a senior applications engineer with Bosch Rexroth Canada, had first-hand experience battling a client over what standard to use. While performing a pre-start safety review (PSR) and overhaul on Japanese presses at a major automotive company, the client's No. 1 guideline was its U.S. corporate standard. “So we were a year discussing what standard we were going to use,” he says, “and of course I’m pushing CSA Z142. … And as we got into it, every step of the way — every design change that was required for safety — they wanted us to use their corporate standard, which wasn’t anywhere close to the level CSA was. So it was constant battle. However, just following a standard may not be good enough. Safety for machinery in the majority of Canadian workplaces comes under the jurisdiction of provincial occupational health and safety legislation. Some standards have been referenced in legislation; however, not all regulators have adopted all standards across the country. In fact, there are no CSA safety standard references in Quebec. Jeremy Warning, a senior associate in the labour and employment law group with Heenan Blaikie LLP and a former prosecutor with the Ontario Ministry of Labour (MOL), says the courts don’t enforce the technical standards — they enforce the legislated standard. “The approach that’s taken by the courts — especially in Ontario — is very, very strict when talking about equipment guarding in particular,” he says. “The courts define a machine to be guarded when you have prevented both intentional and inadvertent access to a moving part. So, in guarding equipment, you have to factor in for the both the accidental access and the intentional access to that moving part. “I think it’s always good practice to follow the highest standard you have as a model to guide yourself, but then there’s going to have to be an ongoing review to determine whether or not that standard is sufficient for the work that’s done in the workplace and how that equipment is actually used on a day-to-day basis.” Regarding liability, Dominic Caranci, a safety product manager with Omron Canada, says he tells customers that standards are 100-percent voluntary and that it comes down to due diligence and who holds liability. “The company running that machine is liable for any accidents that happen, and if they decide a CSA standard is appropriate or an ANSI standard is appropriate — or their own in-house standard is appropriate — I guess if they can stand up in court and defend that to what is in law then they can pick whatever standard they want.” However, he adds, “Harmonization certainly makes it easier.” Wallace then adds that one of the big pushes toward harmonization is coming from global machine builders, who want to be able to build a standard machine and change as little as possible from a safety perspective when selling around the world? “I know some machine builders are also concerned about increased legal exposure in the U.S. if they’re already shipping safer machines to Europe or elsewhere.” Grube echoes this statement. “That’s a much more global market when you have the ability to move these fairly valuable pieces of equipment. And from an engineer’s point of view, I think I would rather know one standard than 20 standards.” He also talks about a simple formula for success to applying standards to machines: “Safer machines equals fewer accidents; fewer accidents equals increased productivity, lower insurance costs and happy employees, which all point to a successful business. It does take some time to become skilled regarding standards, but as with anything, the more you learn the more comfortable you are with the topic.” However, sometimes finding exactly what is needed isn’t as easy as, say, clicking a mouse. Rutherford relays his experiences sifting through standards online: “I just went to go find a standard [online], and I found one — it looked like it was the right one, so I bought it. And it was totally wrong. … It’s tough, especially when you open up a page and there’s 50 of them, and they all relate to the same topic, so it’s like, ‘Gee, which one do I buy now? They’re all worth $150.’ I’m buying standards every time I click my mouse. It can be a nightmare, especially if you’re just getting started.” So where does one start? “You start in your own plant,” he continues. “Go out in your own plant, find out what you’ve got and learn what’s there from when people before them put into place, and learn the ‘old way,’ because the ‘old way’ will tell you a lot, and get you started, and it will say you’re compliant with such and such, or their health and safety committee has approved it based on a standard. Go read the standard it was originally accepted to — what’s the next version from there?” Assessing risk Veugen takes a moment to talk about how standards have to be written to appeal to several different readers involved in making critical safety decisions, each with varying levels of technical knowledge. These include health and safety committee members, engineers, maintenance workers and, in most cases, production. “So you have four different groups of people with the [safety] specialty on their plate — but it is not necessarily their expertise.” “Sounds like a risk assessment team,” Caranci adds. Veugen nods. “Exactly, but if they don’t know how to do a risk assessment and they don’t understand machinery or guarding or safety circuit performance levels…” Caranci jumps in. “It’s getting to the point now where manufacturers in Canada need to start considering having a safety engineering team to not only look at these standards but to evaluate their old machinery. Guys who are as equally important to the facility as production.” Several members agree, and he continues: “The stature of safety is becoming so much higher at the manufacturing level — you see it everywhere. Standards are being continually evolved, and they’re getting much more stringent. Without having that knowledge base, manufacturers are opening themselves up to who knows what kind of litigation.” RESPONSIBILITY & LIABILITY With the advent of Bill C-45, the issue of an employer’s responsibility to his or her employees has become even more critical (if it wasn’t already). Starting things off, Veugen related to the group his experience with retrofitting a piece of machinery that had undergone a PSR by an engineer. However, to him, the PSR was not an adequate scope of work, “just a letter saying the machine’s not safe and that we’re supposed to interlock it. … So the customer comes back and says, ‘You know what, just do what the pre-start says, ’cause if you do, then the engineer will come back and stamp it and say it’s not going to endanger a worker.’ Once again, we say, ‘We’re not comfortable doing that. We don’t believe that’s true.’ And he says, ‘Well, all we want to do is legally cover our butts.’ His question was, ‘If we have an engineer’s report that says the machine is safe and someone gets hurt, we’re not liable, are we?’ ” Warning responds that it may prevent penal liability but may not prevent an order to get the machine up to code. “They may well have some difficulties depending on what [an] investigation reveals because you’ve now advised them that the PSR is not effective. Whether the PSR come into play depends completely on the facts of the case.” VIDEO: Legal expert Jeremy Warning analyzes the legal ramifications of Bill C-45: On Dec. 7, 2007, Transpavé Inc., a Quebec manufacturer, was the first to be convicted of occupational health and safety criminal negligence causing death, two years after a 23-year-old employee was killed after entering equipment that was jammed; the equipment was equipped with a light curtain, which failed. The Criminal Code had been amended in March 31, 2004, to include Bill C-45, which established the duty of an organization to take “reasonable steps to prevent bodily harm” to workers and others. “The genesis of C-45 was the Westray mine disaster,” Warning explains. “The legislative changes that were made were such that it made it possible to apply the criminal negligence provisions in the Criminal Code to organizations and individuals for workplace health and safety issues and accidents where you have the ability to direct someone to do work and how they do work. So what it means to employees and organizations, in theory, [is that] there is the potential criminal liability if you have workplace accident. And I say ‘in theory’ because, to date, there have only been two prosecutions under Bill C-45; only one resulted in a conviction on a criminal change, and that’s the Transpavé case. … They pleaded guilty and were fined $110,000. “We don’t know the full extent to what this criminal liability means,” he continues. “It’s on the books, it’s available for the police and the Crown to use in the circumstances they deem appropriate; however, experience to date suggests that Bill C-45 has not displaced the provincial or the federal health and safety legislative regimes, and those are, right now, still the main implements of penal liability.” The advice Warning typically gives to clients is that meeting safety-standards obligations at the provincial or federal (if federally regulated) level will take care of C-45. “C-45 is a criminal negligence charge,” he finishes. “It requires the Crown to establish a marked departure from the ordinary standard. If the organization and the individuals within it are complying with the legislated requirements, it will be difficult for the Crown to establish that there has been a marked departure.” Making excuses — and changing a culture “I think they’re taking it seriously but not acting on it seriously,” Caranci adds about companies’ legal responsibilities, “and they’re using the current economic state as an excuse. A lot of places we’re going, talking to our customers, they claim to fully understand the importance of safety, but they all give us the same answer: ‘When we start making money, we’ll spend it.’ And until that day comes — which is not today, for these companies — they are very reluctant. “And,” he adds “they’re really careful about what they expose to us as an outside party in their facility.” Grube explains how the consequences of delaying such safety implementations could result in losses in productivity once equipment is forced to be shut down. “I think it’s even more important for manufacturers to be safe in today’s current economy. Companies have let go of many people and therefore any lost time accident can really impact production. There is no time to train and no one to replace the injured operator/maintenance person. And the value of the dollar puts even more pressure on the manufacturer to get the product out the door.” “I totally agree, too,” Caranci says. “But when we’re talking about five, 10, and 20-man shops — little press shops, little metal-fab shops or small Tier 1-type companies — they’re struggling. And asking them to spend another $50,000 or more on a safety upgrade, as much as you throw at them information-wise, they just don’t buy it.” So are manufacturers taking their responsibility seriously? “I do not think people go to work and think they will be hurt by machinery,” Grube says. “Just as no one expects to get into their car and get into an accident. Safety needs to be present 100 percent of the time. The company needs to live and breathe safety.” “That’s a pretty good analogy,” Rutherford says, “but how many of us would buy a car without air bags?” Some companies are putting their employees behind a the wheel of a car without air bags, and Warning addresses how this kind of complacency sets in. “One time, someone does something that’s not quite keeping with the health and safety standard because it’s easier one day, it’s faster, seems like it’s low risk — and, if that practice continues and expands, it erodes  the culture and, eventually, you get into a situation where workers are using their discretion about when they will abide by the safety standards in the workplace. “I think to maintain [a vigilant workforce] requires a very vibrant culture in the workplace that is focused on safety, and that has to start at the top, and it has to constantly be reinforced.” Continuing along these lines, Wallace mentions resources available to manufacturers. “There are some organizations – the IAPA [Industrial Accident Prevention Association] is one – that go into companies and try to assist them with setting up processes like that and help keep that culture vibrant.” Warning adds to this point: “There are also numerous consultants with health and safety backgrounds that can be brought in to design programs and assist with rolling them out, reinforce them.” He also says they can use consultants to do random internal inspections so they can find out where the inefficiencies are. “This is all part and parcel of the due diligence that’s required should you have an event. You will need to be able to explain your procedures and policies … to avoid or defend any charge that may be laid.” PRODUCTIVITY When talking with customers, Caranci says there are three things to talk about. If appealing to a potential client’s softer side (“Do you want to be the one to call the family of Joe who just got hurt?”) and introducing them to recent cases on the MOL’s website don’t do the trick, he bring up the financial benefits. “The financial side … works really well with the business managers of the company because they just see safety as a capital expense,” he says. “Put it in their mind that a safe plant will get you lower insurance premiums, reduce your financial and production risk; and an accident will cost you much more than they probably realize.” Veugen agrees, saying, “It’s important not to look at safety as a burden but as an opportunity to update old equipment.” Rutherford adds that if a company was spending the money performing a safety upgrade, it makes sense to make every aspect of the machine better, too. “If we’re going to do safety, let’s see if we can make it a more reliable machine and run better. If we’re going to spend the money on that, let’s make it run faster, let’s make it run smarter.” Sometimes just doing anything, instead of doing something correctly, can be a waste. Caranci quoted his favourite statistic: 80 to 85 percent of all light curtains are installed incorrectly; safe distance is either calculated incorrectly or more commonly not calculated at all, or they are not wired incorrectly. “Just trying to get a checkbox on a safety list,” he concludes. And given the ever-increasing selection of differently priced products in the market, Grube says a good place to start is with a risk assessment. “Without risk assessment, you could be over designing your safety system and flushing money down the drain or, even worse, under designing.” In his opinion, the CSA Z460 Control of Hazardous Energy standard contains very good info on risk assessment, with a nine-step approach explained in Appendix C. The process typically involves reviewing the operation of the equipment, identifying associated tasks and potential hazards and using these to complete a risk estimation. VIDEO: Legal expert Jeremy Warning analyzes the legal ramifications of Bill C-45: “By using risk assessment, newer standards and integrated solutions, the designer will have many more flexibilities,” he says. “Safety will become an intrinsic part of every machine and not an add-on. The first step of risk mitigation for the OEM is to remove any hazards from the design at the beginning. The remaining hazards must be mitigated using guards, safety control systems, secondary safety protection [glasses, gloves, etc.] and processes. Time and time again, I see a small investment in safety that can pay off in the future. The cost of an accident can be much higher than the cost of the upgrade. Not to mention the human cost.” According to Wallace, automation is able to mitigate a lot of the risks. “Sometimes the only practical way of running a machine safely is to increase the automation — no question.” However, Rutherford blames a lack of good, solid planning on people’s tendencies to think only in the short term — a practice exacerbated by the current economy. “People are thinking in two to three-year increments; no one is thinking 20 years down the line anymore. … When automation first came in, everyone had a long-term path; it was to put robots in, and then they’d do this, and then do that. Safety should be a huge part of a long-term plan.” He follows this with a question to readers: “How many companies are currently planning for new technology, like safe motion on servos, for the future?” “Believe it or not,” Veugen adds, “safety is new to a lot of people. It’s an anomaly of the 2000s.” But he still believes the level of expertise is growing. “The industry has gotten a lot, lot better, but it still has a long way to go.”
Our experts look at the technologies and trends to watch for in 2010.
Our experts examine current safety standards and the push toward harmonization.
Our legal expert analyzes the legal ramifications of Bill C-45.
Our experts talk about education and long-term safety planning.
Our experts discuss how to improve productivity with safety and avoid complacency.
Running down and torquing the lug nuts that hold the wheel to the hub is seemingly one of the simpler aspects of building an automobile, but it has proven one of the most difficult to automate. This is a difficult manual job, as well, because of the size and weight of the nutrunner and the need to tighten the nuts on two wheels in approximately 40 seconds. If the position of the lug nuts is known, a robot can easily position the nutrunner to deliver the needed torque. The problem is that typically the vehicle is only roughly positioned by a conveyor and the wheels themselves are free to rotate, tilt, and turn. Therefore an ordinary blind robot would never be able to find the nuts. Radix Controls in Oldcastle, Ont., successfully automated this application by using a vision system to determine the position of the wheel including its fore and aft and side-to-side positions and three rotational axes. With this information, the robot can easily move the nut runner into the exact position and tighten the nuts. Automating this application made it possible for two people to move from difficult and stressful jobs to more proactive roles. “As far as we know, this is the first time this application has been successfully automated with the use of machine vision,” said Shelley Fellows, vice-president of operations for Radix Controls. Challenge of automating difficult manual task The automotive assembly plant involved in this application builds vehicles 24 hours a day with just-in-time production scheduling. In a previous assembly line station, two operators (one on each side of the vehicle) place wheels onto the four hubs. The operators then place a nut on each wheel stud and turn the nut a few times. The assembly line conveyor then moves the vehicle to the next station where the lug nuts are manually torqued down. In the past, an operator on each side of the vehicle would locate the first tire, guide the nutrunner into position, torque the nuts down, move to the second wheel, guide the nut runner into position, and torque the second group of nuts. The operators have only 43 seconds to complete this entire operation. “The nut runner is heavy, unwieldy, and generates a lot of counterforce,” Fellows said. “As a result, this is a very physically demanding job that is prone to workplace injuries. All of the major automobile manufacturers have tried to automate this job but they have run into some very significant challenges. These challenges arise from the fact that the vehicle cannot be repeatably positioned on the assembly line.” The conveyor moving the vehicle is not accurate enough to position the vehicle in the line of travel axis — the x axis — nor in the axis perpendicular to the line of travel–the y axis–accurately enough for a robot to position the nutrunner on the nuts. But even if the conveyor was more accurate, the wheel has the potential to rotate in three different axes. It can be turned slightly to the left or right, tilted, (also known as camber) and rotated around the axles. All five of these axes of motion must be precisely known for the robot to position the nutrunner with the required degree of accuracy. Adding to the challenge is the fact that the plant produces vehicles with a wide range of wheel types that are intermixed on the production line. Developing machine vision application “This application is impossible to automate unless the robot can reliably and repeatably locate the nuts,” Fellows said. Radix Controls took on the challenge of developing a machine vision application that could determine the position of the nuts in five different axes within a few seconds as needed to meet the cycle time requirements. The innovative application relies upon two Cognex In-Sight 5403 vision systems to locate each wheel. Radix selected In-Sight because it provides a complete solution in a modular package that does not require any additional hardware or other equipment. The 60 x 110 x 80 mm package of the vision system easily fits within the tight confines of the manufacturing plant. The In-Sight 5403 model was selected because it offers a resolution of 1600 x 1200 pixels and an image acquisition time of 15 frames per second; it is ideally suited to meet the high accuracy and short cycle time requirements of this application. The vision application relies on Cognex’s unique PatMax pattern matching technology to quickly locate the wheel in the image. PatMax can be programmed to recognize any pattern simply by highlighting the pattern in an image taken by the camera. Radix engineers programmed PatMax to recognize each of the wheels used in the plant. The system has been set up so it can be easily programmed by plant personnel to recognize new wheel types. The information backbone that runs the assembly line communicates with the vision system to let it know which type of wheel will be on the next vehicle and the vision system loads the appropriate program. Cognex’s circle finder tool is then used to precisely determine the location of the center of the axle. The company’s edge tools inspect the feature in the center of the rim to determine the angle of rotation of the wheel. When the first image is taken, a laser generates a crosshair on each wheel. Then the first laser is turned off, a second laser generates another crosshair from a different angle and a second image is acquired. The edge tools are then used to inspect the crosshairs in each image. The coordinates of the crosshairs are passed to a program written by Radix for the camera that uses the differences between the crosshairs to calculate the angles at which the wheel is turned and tilted. The system then passes this information to the controller of a Fanuc robot. The robot swivels its wrist to match the angles to which the wheel is tilted and turned and rotates the nutrunner to match the wheel’s angle of rotation. Next, it guides the nutrunner square onto the lug nuts. The nutrunner is cycled and tightens the nuts to the proper torque in a few seconds. The robot then moves to the other wheel on its side of the car and, again, guided by the coordinates and angles provided by the machine vision system, places the nutrunner onto the lug nuts and tightens the nuts. The application has been in operation for 18 months with greater than 99.6-percent uptime (including system errors like missing tires, water on tires, etc.). Calibrating the robot to the vision system The ability to quickly calibrate the robot to the vision system is important because of the potential for the vision system to be bumped by equipment moving in the area. The operator actuates the calibration command on the vision system which determines the centerline position of the wheel relative to its own coordinate system and sends the coordinates to the robot controller. The operator then jogs the robot to position the nutrunner on the wheel and the system determines the offsets between the robot’s and vision system’s coordinate systems. By entering the offsets into the robot control system, the complete coordinate system used by all of the vision systems and the robots in the cell are then synchronized. The workcell is fully calibrated in less than a minute with the custom features on a specialized calibration target, and completes the automatic dynamic calibration sequence in under two seconds per cycle. Radix Controls provided the vision-guided robot application as part of a complete solution including: programming; custom lighting design; integrated robotic communication and robot programming; and, full controls design including safety controls, coordinated installation, startup and systems training for operators, maintenance and engineering. “The key to successfully automating this application is the coupling of machine vision and robotics to accurately and repeatably guide the robot to the proper position,” Fellows said. “Automation provides a substantial cost savings to the automobile manufacturer and also improves quality by ensuring that the lugs are repeatably tightened to the proper torque.” www.radixcontrols.com www.cognex.com
Muting, applied in numerous safety-related automation applications with light curtains, is the temporary suspension of the protective field for access guarding into a danger zone without the safety outputs turning off. Muting is always started by at least two independent sensor signals, typically with the use of retro-reflective sensors. By allowing transported material faster access into or out of a danger area without interrupting material flow, muting provides productivity gains in the automation process and guarantees personnel protection at the same time. The two most common types of muting solutions are two-sensor parallel and four-sensor sequential. Figure 1 shows an example of four-sensor sequential muting at a robot station, accomplished with four inductive muting sensors (MS1 to MS4) that are activated in sequence by the carrier. This type of muting is used when each piece of transport material has the same dimensions and enough space is provided for entry and exit. In this case, the muting controller checks only the sequence of the sensor activation/deactivation; the time interval between the sensor signals is not that important. Two-sensor parallel muting, shown in Figure 2 in a palletizer system, is activated by two muting sensors, which cross over each other. Note that the crossover point in the “X” made by the sensors is located inside the “danger” zone. This is done to eliminate tampering and ensure valid muting signals during the transit. Both sensor signals (MS1 and MS2) must be activated within a prescribed time, basically instantaneously. This type of muting is frequently used when the dimensions of the transport material are not consistent or where space is at a premium. As it stands, an AS-i (Actuator Sensor interface) system can easily incorporate safety components by adding an AS-i safety monitor to the system. However, adding the muting functionality to the safety monitor is the next step that will provide an especially flexible automation solution to the growing AS-i installed base. The required sensor equipment is made up of muting and safety sensors, which are directly polled by the AS-i interface and then analyzed by an AS-i safety monitor. An example of a cost-effective Safety At Work AS-i solution would be to lay the yellow AS-i flat cable on one side of the system and the passive elements on the other, selecting retro-reflective light beam devices as muting sensors and a transceiver-type light beam safety device with a deflecting mirror. Connecting the muting sensors, muting start/restart button and muting indicators would be done with standard AS-i input and output modules. The standard light beam safety device would be selected with an integrated AS-i interface and then connected to a safe AS-i input module. To achieve safety Category 3 or 4 in accordance with EN ISO 13849-1, MS1 and MS2 muting signals with a two-sensor parallel muting solution would use separate standard AS-i input modules. An optional configuration could have a muting sensor via a standard AS-i input module and a second independent software signal via the AS-i master output bit. With a four-sensor sequential muting system, the muting sensor signals (MS1 to MS4) would be integrated with two separate standard AS-i input modules (MS1/MS3, MS2/MS4). Optionally, two signals (MS2, MS3) can be transferred via a standard AS-i input module, and two independent software signals (MS1, MS4) can be transferred directly by the control unit via the AS-i master. For the muting start function and the muting status indicator, the same AS-i slaves can be used where possible to reduce costs. In the past, a separate muting controller had to be integrated into the system by an additional safe AS-i input module. This is no longer necessary. The safety monitor, with muting functionality built in, can now monitor and evaluate the muting equipment. One distinct system advantage, depending on the number of AS-i addresses, is that several muting areas can be configured and monitored by a single AS-i safety monitor. The configurable muting modes can be changed at any time with the safety monitor configuration software (ASIMON). This would reduce the number of components and result in a simpler and faster system to start up and maintain. With muting functionality available in AS-i safety monitors, existing and potential users of AS-i now have a cost-effective way to add muting solutions while still maintaining personnel safety and increasing system productivity. Mark Smokowicz is the lead product manager and safety products manager for Leuze electronic, which serves Canada, the U.S. and Mexico. Leuze is a long-standing AS-i SaW consortium member and will release a certified version of the AS-i safety monitor with muting functionality.
All participants of Manufacturing AUTOMATION's 2009 machine safety round table this fall were asked what technology or trends they saw as important in the upcoming year. The results were varied, but reducing costs and ever-increasing legal enforcement were two standouts. Jeremy Warning, a senior associate with Toronto's Heenan Blaikie LLP, saw increased regulation and enforcement as a key trend. While on Ontario’s Ministry of Labour website, he noticed the total amount of fines collected in recent years, with a jump from $12 million in 2007-’08 to $28 million the next year. “And I don’t think this a trend unique to Ontario,” he added. “Jurisdictions across the country are increasing the penalties available under provincial legislation related to health and safety. It’s something that’s going to pervade across the country because the jurisdictions look at each and they will change to keep pace.” Number of convictions and amount of fines per year in Ontario   2005-’06 2006-’07 2007-’08 2008-’09 No. of convictions 326 856 1,191 1,303 Fine amount $6,069,251 $8,821,380 $12,007,535 $28,272,120 Jim Grube, safety systems product specialist with Siemens Canada, mentioned control-reliable circuits. “Tight integration of new safety technologies, such as safety networks, safety PLCs and safe drives, allows the application to be more flexible.” At Siemens, they believe all devices will have some type of safety in the future, so they have their Totally Integrated Automation concept that includes safety PLCs, wireless safety, wireless HMIs with safety, safety rated drives and servos. Allen Rutherford, senior applications engineer with Bosch Rexroth Canada, brought up putting cameras inside danger zones. “So leave the guard in place and look at the monitor. Your touch screen can have little webcams showing you inside the hazard zone, and you can do first-diagnosis right there without putting yourself in harm’s way at all.” As well, he mentioned how web, email and pager technology are helping keep supervisors informed when safeties are violated. And finally, he had to mention safety PLCs, which aren’t new “but have recently become more widely implemented.” Making use of one product in many ways was on Walter Veugen’s mind with logic-based safety. “You can have light curtain protecting three different modes of operation," said the president of integrator Veugen Integrated Technologies. "A light curtain has three different functions depending on what the machine is doing.” “Another trend that’s starting to emerge is safety being considered earlier in the design stage … before the machine’s even built,” said Omron Canada safety product manager Dominic Caranci said. “I know that’s a long way from being adopted into North American [standards and] culture, but it’s one of the things [with its] origins in Europe.” For Beckhoff's Calvin Wallace, “Safety PLCs and safety networks are a trend to look for because you can distribute your safety I/O throughout the machine or your line on the same Fieldbus as non-safe I/O and servo drives. This technology continues to drive the cost of safety down while significantly simplifying your control architecture.” Caranci agreed. “The key point there is that the price of all the safety technology is drastically coming down. … And as the costs of these products are going down, we’re seeing them being used in non-safety applications, which inherently improves the reliability of whatever that application is.”
Canadian press brake manufacturer Accurpress created its first tandem press in response to a customer’s request. The customer didn’t want to buy an expensive custom machine with the sole purpose of bending longer parts, which would rarely have operated at full capacity. The end result was anything but an awkward monolith taking up space. The company, with a manufacturing location in Surrey, B.C., set out to develop a tandem machine by coupling two of its Accell press brakes, using the “master and slave” principle. “It was clear to us that the coupling should be via the control system,” says Alex Kvyatkovski, R&D team leader at Accurpress, referring to the machine’s PC-based control from Beckhoff Automation. His team achieved the coupling with Beckhoff through real-time Ethernet. To switch from simplex to tandem, all the operator has to do is select tandem mode on both machines, specify which is “master” and which is “slave,” and upload the recipe to be processed to both control computers. In tandem mode, the two machines operate as one and can bend sheet metal components with a length of up to 14 metres. Beckhoff control technology synchronizes the two machines and controls the bending process, including the associated material handling equipment. Each press has a C6240 control cabinet industrial PC (IPC) from Beckhoff using Windows as operating system, and the TwinCAT automation software platform. Beckhoff CP7037 control panels with TFT displays are used as the human-machine interface (HMI). EtherCAT links the input/output (I/O) level with the control system. PC-based control Until 2001, the Accell, Accurpress’ most advanced press brake, used a controller designed specifically for press brakes. While its performance was satisfactory, it was costly and had limited programming flexibility, which Kvyatkovski found presented “significant obstacles” to maintaining a competitive edge. Accurpress had experimented with using computers to control machines and tried different approaches. “While some people back then unfairly thought of computers as unreliable, we nevertheless started using them in ’96,” Kvyatkovski says. “So by 2000, when we saw what Beckhoff had to offer, we jumped on board right away.” Beckhoff’s philosophy is essentially PC-based control, and doing more control with less hardware. A single industrial PC can do the work of multiple PLCs while also controlling motion and running HMI. For Accurpress, PC-based control was a cleaner, more cost-effective solution than using hardware PLCs, and much less expensive than the original controller. Just one centralized controller can be less costly because it has fewer proprietary components than the PLC. It also means less programming. “Typically, you only have to program that one controller versus multiple hardware PLCs,” says Shane Novacek, Beckhoff’s marketing communications manager. “You program the IPC once and you don’t have to worry about getting that code to several other controllers, because the IPC is an all-in-one, multitasking device.” None of the benefits of PC-based control are lost when the machines are in tandem mode. Real-time Ethernet coupling gives the presses precision, repeat accuracy and process reliability. Whether in simplex or tandem mode, it operates with a bending speed of 20 mm/s and a parallelism accuracy of ±0.01 mm, made possible by closed-loop servo hydraulics technology, controlled by the IPCs. The controllers of the coupled Accell press brakes communicate via the publisher/subscriber model, creating a permanent bidirectional data link. The two machines can exchange information on set and actual position, velocity, recipe step, job and machine status, and special key positions. Even in tandem mode, Accurpress machines have almost unlimited flexibility that comes from having a clean hardware architecture and open TwinCAT automation platform. Different recipes with different start on target positions allow different angles. Though 90-degree angles are the most common, the machines can handle much more complex 3D shapes. “Some angles are 90 degrees, some obtuse, some acute,” Kvyatkovski says, “but you can also do a lot of what’s called ‘fade-away bends.’ ” He says a boat manufacturer uses Accell machines to make fade-away bends that are 120 degrees at one end and roughly 170 at the other. Accurpress can adapt any press to customer requests without special hardware and can modify or complement functions with minimal effort. Customers enjoy a shorter-than-average lead time: only two to three months for major customization requests. He adds that such flexibility would not be possible with an off-the-shelf controller from a third-party vendor and that “several lucrative machine orders would be lost as a result.” PC-based control brings similar benefits in assembly, packaging and converting, plastics technology, food processing, automotive and tire, alternative energy technology, semiconductor, wood, timber and other areas. Because this type of system is compatible with Windows, a user could use it in conjunction with Excel spreadsheets, e-mail or SMS alerts to maintenance crews. And there’s no need for those proprietary hardware cards that are installed in a controller to manage data in the Fieldbus language — a simple Ethernet card will do. “With EtherCAT you’re able to get very, very rapid communication at microsecond level speeds for passing data from device to device,” Novacek says. For manufacturers that want to try EtherCAT but are already equipped with machines that use DeviceNet cables, a complete retrofit isn’t necessary. Master and slave gateway terminals would allow data to pass freely from an EtherCAT device to a DeviceNet-enabled machine. Safe motion control Tandem press brakes are a cost-effective way to bend materials of otherwise unruly proportions. “Anything big, long and metal,” says Alex Kapulnik, who is Kvyatkovski’s engineering partner at Accurpress. He has seen the machines joined in twos, threes and even fours to manufacture submarine hulls for the military as well as the long metal casings that house cables in construction projects, and agricultural equipment, such as the rotating part of a combine. Tandems, and often “tridems,” are also used for light pole or flagpole manufacturing. Poles can be octagonal or, in a process called “bumping,” multiple small bends can create a rounded look. Accurpress recently mounted a sheet follower at the front of its Accell press brake to handle materials too heavy for an operator to lift. TwinCAT software synchronizes the motion with the press via an electronic axis, and the sheet follower safely and precisely lifts and lowers heavy materials. The Accell machine further reduces operator intervention by making on-the-fly adjustments while metal is being formed. TwinCAT calculates bending positions automatically and coordinates the motion control. Built into each press brake is safety control in the form of TwinSAFE, described as follows on the Beckhoff website: “The TwinSAFE safety PLC communicates with the industrial PC, safety inputs/outputs, safety-related drives, and safety sensors through the Safety over EtherCAT protocol.” “In tandem mode, both machines are synchronized to run in parallel, but the same safety controls on each machine take care of safety,” Kapulnik says, “and the machines are in compliance with safety standards in Europe, Canada and the U.S.” Kvyatkovski says customers have now come to expect the flexibility they have experienced using tandem press brakes with a PC controller. “More and more, we find that press brake users are seeking synchronized presses like ours,” he says, “while traditional PLCs and proprietary designs are quickly losing favour.” Michelle Morra is a freelance writer based in Toronto.
Turbines housed in aircraft engines are subjected to some of the roughest conditions imaginable. They are pieces of mission-critical equipment that must perform flawlessly at speeds of 30,000 RPM in temperatures greater than 800°C for hours at a time. Therefore, engine manufacturers fully understand that even small surface defects can reduce performance, increase maintenance costs and reduce the useful life of an aircraft engine. They need to inspect turbine blades very carefully to maintain the efficiency and reliability that the air transport industry requires. One particular North American manufacturer inspected its blades by hand and human eye. The highly trained inspectors would measure hundreds of features and check for surface defects at depths in the order of thousandths of an inch. Manual inspection was not only costly, in terms of time and labour, but it was subjective as well. Results were variable and even differed between inspectors. Finally, because manual inspection was so time consuming, there was no systematic inspection of every blade; only a sampling of blades would be inspected. Clearly, the manufacturer required an approach that would allow systematic inspections of the blades, save time, and yield consistent and repeatable results. That was when they approached Orus Integration Inc. in Laval, Que., to design an automated turbine inspection system. Project manager Louis Dicaire says that early on in the project, the development team learned that flexibility, repeatability and precision were absolutely necessary for success. During development, the Orus engineering team relied on their previous experience — they designed vision-based metrology systems for the Canadian military and aerospace industry. They also worked closely with Genik Automation in St. Jérôme, Que., for part handling and mechanical engineering of the machine. Orus calls the system the INL-1900x2T. A single enclosure houses two stations that perform the inspections. The metrology station features two Basler GigE cameras at 1920x1080, each fitted with a large field of view telecentric lens (non-perspective lens) and two collimated LED blue (520 nm) lights. The surface inspection station uses four Basler GigE cameras; the resolution of the first camera is 1920x1080 for the surface inspection, and the remaining three offer a 640x480 resolution for surface inspection of areas that are hard to reach with a single camera. Two CCS diffuse on-axis lights and one CCD diffuse backlight illuminate the surface station. A Fanuc six-axis LR Mate 200iC robot and 4U controller and Omron PLC round out the hardware components. The software is based on the Matrox Imaging Library 9.0 with Processing Pack 1. The blade’s journey The INL-1900x2T has three inspection roles to fill: verify several hundred metrology features of the blade, inspect both sides of the turbine blade and other critical surfaces for defects, and validate the part’s character markings. The entire inspection procedure takes 15 seconds per part. To perform a batch inspection, an operator first scans the barcode on the job sheet with a scanner and loads the pocket wheel with the carousel that holds the parts. Then the wheel indexes the first part while a height detector validates its y position to ensure the part was properly loaded. Then the robot picks up the part by its blade section and carries it to the metrology station, which is illuminated by the two collimated lights. With the camera’s telecentric lenses, and the four-inch slab of granite to absorb heat and vibrations, the INL-1900x2T enjoys a very stable optical system. “Under these conditions, the contrast of the round sections of really shiny objects appear super sharp,” Dicaire explains. Precision is extremely important. “The robot is very repeatable, but cannot place the blade with the precision that we need, which is smaller than 10 microns,” he says. Orus’s solution was to rotate the part and acquire the images at high speed. Depending on the feature that needs measuring, the software minimizes or maximizes a specific feature. When an image of a particular reference point, called the datum, matches the original CAD drawing, the software identifies it as the reference image. Then the metrology software measures the part’s parallelism, length, radius, angles and other feature. Since there are many datums to optimize, this step is performed more than once. The software records results for hundreds of features and 50 tolerances. After the software records the metrology results for all of the blade’s features, the robot places the blade in a three-pronged gripper that is mounted on a Y-Theta station. The clamp rotates the blade 360 degrees to inspect both sides for surface defects. Then the software verifies the part’s character markings: first by stitching together several images to form a complete image and then by passing the OCR algorithms that determine the character. When the inspections are complete, all the results for the part are logged; all data is retrievable for reporting. If the part passes inspection, the robot puts the part in a good-parts chute. If a feature has failed, the part is held in the clamp and information is displayed on the screen so the operator knows what to correct on that specific part. Then the gripper releases the part into a reject chute. The wheel turns, indexes the next part and the process repeats for all parts in the carousel. MIL power Orus has used Matrox Imaging Library (MIL) for almost nine years. “This is probably the project where we dug deepest inside the library,” Dicaire says. One of the implemented algorithms features an adaptive threshold: the algorithm dynamically locates bright spots in dark areas and dark spots in bright areas. For other operations, the developers at Orus used the GUI interfaces for several MIL modules: OCR, Edge Finder, Geometric Model Finder, and of course Metrology. The metrology software was almost exclusively developed with the GUI so the system could learn the parts. Indeed, the INL-1900x2T’s flexibility means the system can accommodate several different parts, even new parts that are still under development. “With the GUIs,” Dicaire explains, “we can build a system that lets our clients be more autonomous with the final product. We find that, with the level of complexity of our projects, MIL’s ease-of-use, performance, flexibility, and the great support from [Matrox Imaging’s] Vision Squad team are the reasons we continue to develop with MIL.” Measuring up Dicaire says the challenges involved in designing metrology machines are always the same: repeatability, precision and linearity. To get the system to return predictable, repeatable results, the software must exhibit fine sub-pixel accuracy; the machine shows ±3 sigma under five microns. Of course, an image is only as good as its lighting, and Dicaire notes that the system required a stable and high-performance optical system. To achieve the required precision, Orus used a military-grade calibration target to calibrate both cameras at the same time. Though the INL-1900x2T saves thousands of hours of labor, its main advantage is its ability to perform very complex analyses while offering a simple interface and a very easy-to-use concept for the operators. “This project uses an array of field-proven technology: robot, axis, vision library. All of this enables the machine to grow and adapt to the client’s future needs. Except for the mechanical design, almost all components are off the shelf.” “This machine is a mix of technologies that are all dedicated to make the vision system work in optimal conditions,” Dicaire says. “It’s a great example of what we can do.” Sarah Sookman is a media relations specialist with Matrox Imaging in Montreal.
A custom integrator of turnkey automated inspection machines for quality control, Cincinnati Automation "saw the light," adopting a new LED backlit conveyor to convert automotive part gauging from a step-by-step to continuous process, more than tripling throughput. The AccuVision conveyor from Conveyor Technologies Ltd. features a grid of high-intensity LED lights beaming up through a translucent urethane conveyor belt. "The backlit conveyor let us change gaging to a continuous operation for faster processing, and with less complex systems engineering," says Phillip Smith, Cincinnati Automation president. "For gaging operations, backlighting is positively preferred," he notes. "You get a silhouette of the part with crisp edges, sharp contrast and no shadows for precise dimensional inspection against the programmed master."  In the past, the Erlanger, Ky., company would have processed the parts on a stationary backlight table, he says. "To gauge overall geometry and edge geometry, which we're doing here, we'd use a pick-and-place system for part transfer and a walking beam to advance parts to the first station for top inspection and on to the second station for side inspection," Smith explains. "We’d have to move parts to the inspection station, then move them off, so doing backlighting on the conveyor itself is a great advantage in speed and simplicity."   Pick-and-place backlit gaging was limited to about 10 parts per minute, compared to 36 a minute for the new continuous conveyor system. And, that higher processing speed is governed by the speed of the part loading system, he notes. He believes a backlit system could easily handle parts at 60 to 120 a minute, depending on part size/configuration and faster loading capabilities. "A high-speed vision system can process a part in less than 100 milliseconds, so theoretically a system could process up to 600 parts a minute, provided you get the parts on the belt that fast," Smith adds.   The continuous gaging system is configured to run 40 different part numbers for the automotive supplier, ranging from five up to eight inches OD.   Robot grippers load the parts three at a time on the 66-by-12-inch translucent belt. Parts advance along the belt to the LED light field, where each is visually gauged by an overhead Keyence digital camera with an 8.5-inch field of view. At the end of the conveyor, a second Keyence camera with a 0.5" field of view gages the side geometry, catching the lead edge just as it extends beyond the conveyor. Parts then pass off the conveyor to an incline slide with a diverter flap. Failed parts drop through a slot in the incline. The flap lowers for good parts, covering the slot and allowing parts to pass down to the next station.   Delivering two mega-pixel imaging, the Keyence cameras in the CA system provide 0.006-inch pixel resolution for overall part gaging and 0.0003-inch pixel resolution for edge gauging, based on the respective fields of view. The machine control shows images of each part being gaged, with both views tiled on the screen at the same time along with read-out results. Gauging data can be recorded as a text file to the system's PC for SPC quality control. Integrating backlighting with the conveyor enabled a highly compact design, with the entire machine measuring just 96 inches long by 36 iches wide by 70 iches tall. "This is a very space-efficient, Lean solution for plants," Smith stresses. The conveyor is mounted 55" off the floor, giving plenty of space for stacking parts for conveyor loading and for a scrap bin inside the machine to catch rejects. The bed of the Conveyor Technologies conveyor is only 2.28 iches deep, even with the LED light module mounted inside, for space savings and application versatility. "Backlit conveyors are still relatively new, but we were fortunate in finding a source almost in our backyard," Smith says. Cincinnati Automation specified a 10-by-12-inch light field. AccuVision light fields are available in six widths (two to 12 inches) and five lengths (six to 30 inches). The backlit conveyors can be ordered in belt widths from 2.5 to 24 inches. Made of translucent urethane, the conveyor belt "has really good diffusion properties, a good even light for the camera," Smith says. "The light is bright enough that it washes out imperfections from dirt build-up or smudges on the belt." Cincinnati Automation selected white LED light for the conveyor so that dirt on the belt would be more obvious, to aid in routine cleaning, he explains. Conveyor Technologies also offers red LEDs, which would work just as well for the Keyence cameras, he notes, but have less contrast for the human eye in monitoring against dirt build-up.   The conveyor's array of  LEDs provides a more even light than fluorescents, notes Smith. "With fluorescents you typically wind up with hot spots where the bulbs are. To minimize that effect, we would locate the bulbs further away and install diffuse panels, maybe even a couple of panels. It's more difficult to get uniformity across the light panel.  The way Conveyor Technologies does it, they have rows of high-intensity LED light distributed evenly under the belt and the belt itself is the diffuse panel."   Freedom from frequency oscillation makes LEDs ideal for high-speed digital cameras. Fluorescent "flicker" — oscillating cycles of bright/dim — usually aren't visible to the naked eye, but will be captured by the camera and are readily apparent on the control's monitor screen. "The LEDs may cost more than fluorescents at the component level, but are more effective, operate far longer, and are just easier to work with when you consider everything involved," Smith says. The gauging machine is fitted with dark tinted panels on sides and top to control against ambient light. Located almost dead-center along the I-75 corridor (and only about a quarter-mile off the inter-state), Cincinnati Automation gets a good 50 percent of its work from the automotive industry, typically Tier 2 and 3.   After automotive, its key customer industries come from medical device manufacturing, also strong regionally, followed by packaging and label inspection. Conveyor Technologies uses modular design and engineering innovation to provide performance-enhancing and space-saving solutions to part conveying.  The AccuVision Internal Backlight Conveyor is part of a patented, modular product concept from Conveyor Technologies that is foundation to 15 different low-profile conveyor types. www.cincinnatiautomation.com www.conveyortechltd.com
This is a four-part article outlining the many ways to evaluate a pneumatic conveying system. In choosing a system for the safe, clean conveyance of materials, it seems that the choices can be remarkably complex. Prior to such a choice, a facility is usually operating with, live personnel, open conveyor belts and implements such as buckets. While employees may be protected by proper clothing, masks and goggles, materials are exposed to air and dirt, waste is a constant worry, and expensive equipment is endangered by particulates that can slow or jam it. In today’s operating environment with its constant economic pressures and forced attention on the bottom line, it then becomes mandatory for companies to seek alternatives and improvements such as pneumatic conveying systems. It seems so simple. Why, then, when having to confront all the possible options for such a system, does it appear to require an engineering degree? And even those folks are going to have a hard time when posed with questions such as, should the system be dilute phase or dense phase? Should the system be vacuum, pressure or combination? Given the physical properties of your materials, how exactly will they be best conveyed? What is the friction factor of your solids? How do you calculate the expected losses of pressure throughout the system? Given that oxygen doesn’t mix well with some chemicals, what gas should you utilize? It even gets worse when you find you have to figure in factors such as solids velocities in horizontal, diagonal and vertical pipe runs and gas densities. Okay, Hold Up! Let’s take a deep breath, a giant step back, and remember our original reasons for wanting to do this in the first place. The reasons are relatively simple and, fortunately, so are the choices involved. In evaluating a pneumatic conveying system, a company wants to be convinced of three basic pieces of information: 1. Is the system going to truly automate a process? If a particular process now involves 5 personnel, can most or all of those personnel actually be eliminated from the process and assigned elsewhere? Will it actually be possible to run that process with little to no further attention, save perhaps periodic monitoring? 2. Is the system really reliable? Will the system run 24X7 without babysitting? Will it stand up to the required process; is it robust and seriously proofed against breaking down? How much maintenance will it require? 3. What is the actual cost of the system? The overall price of a system is only the beginning of such a question. How quickly would the system pay for itself?  How much actual time and cost will be saved by its implementation? These questions each tie into one other, and each and all must be answered in detail. Fortunately, if reliable expert assistance is sought, that first set of horribly niggly engineering-type questions need not be solved by a facility, and the important questions as above can be answered fully by an outside expert and to a facility’s satisfaction. An understanding of material characteristics is essential when designing a vacuum transfer system — experts often already possess data about a particular substance’s behavior and will test within a proposed configuration to ensure it will work properly. This knowledge must, by necessity, be extensive; for example, there are often several product grades within the same product group and those forms may have completely different characteristics such as free flowing, sluggish or non-free flowing. One grade of Zinc Oxide may have the consistency of talc, while another might be more cohesive and adhere to inside surfaces of conveying tubes. Experts in pneumatic conveying solutions, such as Vac-U-Max, an early pioneer of vacuum technology, are skilled in designing proper solutions based on application specific needs. Rather than trying to dazzle you with the complexity of the technology, a pneumatic conveying company who routinely designs and builds custom pneumatic conveying solutions will most likely have an idea of how to tailor a system to meet present and future needs and will be able to provide solutions that work properly out of the box in the facility. Individual Cost-Saving Benefits Implementing the correct pneumatic conveying system — or correctly expanding an existing system — yields numerous benefits, and when working with a company that has experience in solving a wide range of problems, switching to pneumatic conveying system is a simple solution that yields amazing cost benefits. Clean Up The right system means reduced or eliminated cleanup. Because the system is fully enclosed, problems with particles escaping and messy accidents are eliminated and so is the labor-intensive cleanup from floors and surfaces, and unnecessary cleaning of machinery. A fully enclosed system also translates to a healthier work environment because it reduces or eliminates worker exposure to hazardous substances and deadly dust that can cause explosions. Although engineers on the plant floor do everything they can to protect workers, such as using extensive exhaust ducting and respiratory protection for the workers in the area, they often continue to search for a better solution.  One such company worked with a pneumatic conveying expert and found an alternative to manually dumping 50lb bags of toxic material into a mixer on the plant floor. The solution was to use a monorail-mounted hoist to lift and position semibulk bags to an unloader which formed a dust-tight seal against the ring on the discharge opening. Agitator pads and an auger under the storage bin were used to deliver material at a controlled rate into a weigh hopper on the floor below, and then conveyed to a blender on an upper floor which enclosed the material path entirely. Reclamation In many industries product reclamation is an important aspect in reducing costs. From fine powdery substances to larger particles such as plastic pellets, pneumatic experts know how to achieve minimal waste. In one example involving the manufacture of marshmallows, bucket-elevator type systems had been being used which just threw starch around. Outside of the need for bi-weekly cleaning, the company was also wasting substantial quantities of a valuable ingredient in the process. The solution was to install vibratory pans within a pneumatic conveying system that shake loose excess starch from the marshmallows as they exit cooling drums. The starch goes through filter separators and is recycled back to manufacturing for reuse. The safe, enclosed system reclaims about 1,000 pounds of starch a day and reduces product loss by up to 2 percent.  Streamlined Production Often companies seek out pneumatic conveying solutions to improve production because the material moves quicker and there is less room for error. This is especially true with processes that are operated with open conveying systems and containers that need to be moved, filled and emptied by personnel. Pneumatic systems convey material from closed hoppers through closed lines and requires little to no intervention. Since labor is one of the highest costs in a plant or facility, reducing man-hours becomes a prime target of any executive interested in reducing operating cost. A prime benefit of a pneumatic conveying system should be the reduction of man-hours. Where numerous staff were previously required to manipulate material, there might now be the need for only one to add material at the front end of the process. One company knew they needed to make dramatic changes in order to assure their future and compete with major players. Their human-assisted blending process had severe limitations, costing the company 20 minutes to blend 1.5 tons of product. With pneumatic conveying, that same output was able to be completed in 20 seconds—a 60-fold improvement. With the money saved implementing more cost-effective operations, the company was able to invest the cost savings into additional R&D, marketing and sales staff. Reduced Maintenance Downtime is one of the worst enemies of a manufacturing facility and immediately impacts revenue.  In addition to reduced or eliminated downtime for maintenance, downtime for cleaning is also considerably decreased with pneumatic conveying systems. A particular facility found that there was virtually no maintenance or cleaning necessary in pneumatic conveying systems because they have few moving parts. They were able to simply clean or swap out hoses and check the motor and oil twice a year. Approximately 30 hours of production per year was added. Adaptability Of course a system should be tailored to the specific material being utilized within the process—and if needed, the system should be able to accommodate different materials if more than one process will be being performed on a line at different times or have the ability to adjust based on the volume of production necessary for specific runs. For example, one company utilized a pneumatic conveying dump station to feed ingredients to blenders for smaller and normal size orders. But for higher volume products such as snack-food coatings and flour, they pneumatically loaded blenders directly from silos at an even greater rate of speed. There are even cases when a system must be mobile so that it can be moved to a different location within a plant. If this is a needed requirement, it can and should be accommodated. Pneumatic conveying systems can be utilized for virtually any material and application, including conveying water treatment chemicals. Keep Your Eye on the Prize The entire goal of pneumatic conveying systems is to automate operations and make them more cost-effective; in effect, to simplify processes. Less complexity equals less downtime, reduced man-hours and reduced overall cost. There should not be added complexity in evaluating and choosing such a system. With expert guidance such as that from Vac-U-Max, a company should be able to follow the evaluation elements as roughly laid out above and stick to them—and thereby attain them. To read more about VAC-U-MAX solutions in your industry, visit www.vac-u-max.com and click on case histories on the pneumatic conveying page or contact us at 1-800-VAC-U-MAX (800-822-8629); email  This e-mail address is being protected from spambots. You need JavaScript enabled to view it . Bruce Boyers is a freelance writer based in Glendale, Calif.
Downtime due to problems with the quality of electric power can be costly. With rising levels of automation and computerization in manufacturing facilities, voltage sag lasting just a few milliseconds can bring an automated factory floor to a halt. Power disturbances are bound to occur, and while some may only briefly interfere with sensitive equipment, others could result in the total loss of power for days. Most international standards define power quality as the physical characteristics of the electrical supply provided under normal operating conditions that do not disrupt or disturb the customer’s processes. (The quality of power supply implies voltage quality and supply reliability.) Therefore, a power quality problem exists if any voltage, current or frequency deviation results in a failure or in a bad operation of equipment. Voltage quality problems relate any failure due to deviations of the line voltage from its normal characteristics, and the supply reliability is characterized by its adequacy (ability to supply the load), security (ability to withstand sudden disturbances) and availability (focusing especially on long interruptions). When power is generated, it has very predictable characteristics. It energizes all electrical equipment equally and satisfactorily. However, as the power travels through the wires and energizes the equipment, the various pieces of equipment can change its quality, making it less suitable for the next application. These changes are especially common in large industrial complexes and include increases and decreases in voltage, momentary power outages and noise on the electrical system; at its most extreme, poor power quality can even cause equipment to malfunction. This can cause business problems such as lost productivity, idle people and equipment and lost data. Voltage sags Voltage sag, or “undervoltage,” is a momentary decrease in voltage outside the normal tolerance, typically caused by the starting of heavy loads, lightning and power system faults. A good example is the starting of a motor. Motors draw more current when they are starting than when they are running at their rated speed. Consequently, the starting of a motor causes voltage sag while it accelerates to its rated speed. Excessive load changes may also cause sags. Computer equipment and controllers may power down depending on the duration and magnitude of the voltage sag. In addition, voltage sags cause loss of data. One way of reducing damage would be to connect sensitive electronic devices to circuits other than the ones large motor-driven appliances are on, try to lighten the load on the affected circuit. If a sag lasts longer, it is classified as undervoltage and is usually caused by circuit overloads, poor voltage regulation and intentional reduction by the utility. The impacts of undervoltages include equipment shutdowns, and the overheating of motors. Voltage swells A voltage swell, or “overvoltage,” is a momentary increase in voltage outside the normal tolerance. Voltage swells are caused by sudden decreases or the turning off of heavy loads and can damage equipment by breaking down insulation. If voltage swells last longer, they are classified as overvoltage, frequently caused by poor voltage regulation. For instance, shunt capacitors designed to improve upon the voltage profile might supply excessive reactive power and cause overvoltages. Periodic loads, such as pumps, cause periodic increases and decreases of amplitude (sags and swells); this is referred to as voltage modulation. Outages Outages, or blackouts, simply occur when power completely drops off line for anywhere between brief moments to several hours. Power outages can be caused by many circumstances, such as storms, which can be accompanied by heavy wind, ice, precipitation and lightning. Momentary outages, which are seen as a dimming or flickering of lights or even a brief loss of power, are caused by short circuits. Short circuits happen when something, such as a tree limb, comes into contact with power lines or when the lines touch each other. When a short circuit occurs, a breaker automatically de-energizes the circuit and interrupts the flow of power. Electrical equipment is designed to quickly open and close the breaker two or three times automatically attempting to clear the problem. An uninterruptible power supply or generator could help mitigate the drop in power in both instances. Harmonics For most of the 20th century, the predominant use of electricity for business and industry was to power motors, lights and heating devices. These uses have little effect on the 60 Hz (cycles per second) sine waveform of the electricity delivered to them from their utility. They are referred to as linear loads, because the current rises and falls in proportion to the voltage wave.  A few industries, such as steel mills and aluminum smelters, used electricity to power arc furnaces, which distorted the sine waveform because the current flow was not proportional to the voltage. These loads are referred to as non-linear loads. Non-linear loads cause waveforms that are multiples of the normal 60 Hertz sine wave to be superimposed on the base waveform. These multiples are called harmonics. In the last 20 years, there has been an explosion of microprocessor-based equipment, which are also non-linear loads. Equipment widely used in offices and manufacturing not only creates harmonic issues but are also susceptible to harmonic disorders. These include are computers, monitors, adjustable-speed drives, welding equipment, transformers, etc. The list goes on and on. The invention of all these sophisticated electronic gadgets and circuitry has increased the problems associated with harmonics immensely. Transients Transients can be defined as sudden, brief increases in current or voltage in a circuit that can damage sensitive components and instruments. These disturbances are shorter than sags or swells, and are caused by sudden changes in the power system. Two main categories of transients based on their duration are switching surge and impulse spike. Switching surges are caused as a result of resonating circuits with switching devices. Large capacitor bank switching can cause resonant oscillations, leading to surges causing tripping or even damaging protective devices. Electronically controlled industrial motors are particularly susceptible to these transients. Impulses are very short spikes, in the order of a few microseconds. They are mainly caused by lightning strikes, arcing and insulation breakdowns. Most power systems are protected from surges and spikes using a transient voltage surge suppressors (TVSS) device and by surge dividers and arc-gaps at high voltages and avalanche diodes at low voltages. If these disturbances are encountered by monitoring systems, depending on the magnitude of the spike, it may saturate or damage the monitoring sensors. Furthermore, TVSS systems are an effective first step toward power quality management. They’re generally specified to protect the incoming AC power at the service entrance, the branch panels and individual sensitive loads. Additionally, signal and control circuit conductors are also protected to eliminate any activity from coming in the “back door.” It should be considered mandatory where there are safety-to-live and public safety considerations involved. Applications include water and wastewater treatment plants, manufacturing systems, industrial robots, power system controllers, and controllers in food-processing and petrochemical plants. Power-quality monitoring is extremely important: it provides a continuous health check of a facility’s power system to see, diagnose and avert looming problems. Harshad Singh is a technical sales specialist with Gescan Ontario in Milton, a division of Sonepar Canada.
What kind of controller is best for your application? Is it a PLC (programmable logic controller) — or perhaps you should use a PAC (programmable automation controller), or maybe a PAD (programmable automation device)? When it comes down to it, the name is not that important. What is important is developing a clear understanding of your needs and then finding the controller that best targets them. In the world of industrial automation, technology has evolved leading to innovations in controllers and I/O, enhanced engineering tools and entirely new system architectures. The controller we are familiar with can now take virtually any size and shape, from a traditional industrial PLC, to a PC-based controller and even a “nano-sized” brick. On paper, an automation controller must cover a broad range of application requirements. The platform should offer standards-based openness; flexible, single-database integration for the entire system; standard IEC-61131-3 control programming and configuration languages; the ability to create preconfigured libraries of reusable code; and object-oriented design of complete system architectures. The reality is that very few controllers can truly provide these capabilities in one package. But such solutions do exist, so it’s important to identify unique control applications and then look at what the controller should do to help you solve the application. Following is a list of six control applications: If we look at each of these, and identify some core elements that you must have, we can paint a picture of what the modern automation controller can deliver. 1. Logic Control Performance and processing speed: In machine, factory or process control, controller performance is a key element in productivity gains. As you strive to improve the electro-mechanical performance of your application to yield higher throughputs, the performance of your automation system must keep pace. The execution time, high-speed interrupt handling and “segmentable” scan times of your controller all contribute to application performance. Scalability: Ideally, you would have one engineering environment to configure all of your applications, which, in turn can be downloaded to the target platform meeting your requirements. This separation of program and platform allows you to focus on solving the application problem, followed by selecting the best, most cost-effective platform for your specific application. Configurable system-wide diagnostics: You can always program diagnostics into your code, but this takes time, and often is sacrificed to meet project schedules. A controller with built-in diagnostics that can be easily enabled or configured ensures that this important aspect of your solution won’t be skipped. Availability of multiple programming languages: Relay Ladder Logic is expected in a logic controller, but aspects of your application may be better implemented using graphical function blocks or a high-level programming language. The IEC 61131-3 standard for PLC programming languages defines five languages that range from ultra-efficient “machine code” to the graphical representation of sequences. Potential for reusable code: For industrial automation, leveraging a library (from the supplier or defined by you) of common program elements and using these elements repeatedly reduces implementation time and improves program consistency. Investment security: Rather than demanding new products, many users push for longer life cycles for their existing products and architectures while taking advantage of advances in technology. The result is having the “latest and greatest” without the need to “rip and replace.” 2. Motion Control Tight integration of motion and automation: Not only is manual integration time consuming but it’s prone to errors and maintenance challenges. Ideally, motion and automation engineering would be done in the same software with the same languages. High-speed, deterministic performance: Motion applications tend to be very fast and therefore require real-time, high-performance controllers. However, speed is nothing if it’s not repeatable. For proper operation, the controller needs to execute your defined tasks the same way every time. Optimally, you want fast, deterministic execution with very small jitter of all elements of the motion solution from controller to network to drive to the feedback mechanism. The controller should be designed to make it easy to engineer motion applications: The ability to propagate libraries and templates throughout the application is very important to minimize rework and promote the use of standards. The use of standards-based, pre-defined, tested functions saves significant time. Access to standard algorithms (like circular interpolation and 3D movement) frees you to focus on configuring your application rather than programming base motion functionality. Tools to optimize performance: Motion applications tend to be very fast. To optimize performance, tuning and trace tools are absolute requirements. These tools must look at the entire motion solution to perform accurate tuning. Reliable and established networks to support the motion controller: Proprietary networks tend to limit you to only one supplier. Ideally your motion controller supports an established network standard. It is critical that the network also accommodates high-speed deterministic motion applications. The network should not introduce any limits to the performance of the motion solution — the network should be transparent. 3. Flexible Architecture Improved integration to achieve higher performance and lower engineering costs: Frequently, the ideal application solution may require specific hardware and custom software technology to tightly integrate with your controller. An open architecture makes it possible to embed the custom program directly with the automation control program. Additionally, you can achieve high-performance due to the ability to directly plug interface modules into the platform bus. When an application is outside the capabilities of classical controller architecture, open architectures are essential. Connecting non-standard communication busses, PCI-bus based servo controllers, specialized vision applications and applications written in non-PLC programming languages are not easily done in a classical architecture. Automation platforms utilizing an open architecture allow the user to develop their own integration solutions that are run as part of the controller execution. The ability to think beyond typical restrictions: How often have you wished for more memory or processing power? Traditional controller platforms limit you to specified resources – if you need more, you must purchase a different platform. Automation platforms based on an open architecture provide the flexibility to add additional memory, or even to take advantage of faster CPUs. Leverage continuous platform innovation: Hopefully, we are all familiar with Moore’s Law. Computer processor speed directly impacts controller program performance in an open architecture controller. A traditional controller cannot offer the ability to leverage this rapid innovation. 4. Process Control Availability of pre-engineered solutions, templates, and extensive libraries: Process users look to leverage pre-defined objects from libraries (i.e., cascade PID) rather than “rolling their own.” This speeds up configuration and makes the resulting project more consistent and maintainable. It would be advantageous if you could also create your own library objects based on your unique control strategy. Ability to select program execution speed: The normal reaction to controller speed is “faster is better.” However, for process applications regulatory control loops normally scan in the 100 to 500 millisecond range. In some cases, it could be detrimental to have control logic execute any faster – possibly causing excessive wear on final control elements such as valves, resulting in premature maintenance and process issues. It is important to have the ability to select program execution speed. Emphasis on design using a top-down approach to engineering: Process users spend a lot of time on up-front design and overall program structure. This focus on upfront design minimizes costs, compresses project schedules and creates applications that can be maintained by plant personnel over the long term. Since many process applications are large and plant-wide in scope, the ability to propagate libraries and templates throughout the application is very important to minimize rework and promote the use of standards. Ability to be installed in a hostile environment: Many process applications are in hazardous (i.e., explosive) environments. Additionally, the environment may be moist or corrosive, potentially leading to damage of critical electronics. The automation platform and associated peripherals must withstand such environments without undue installation costs or complexity. Embedded knowledge: Technology is just part of the challenge to produce an effective automation platform for process applications. It helps tremendously if the supplier knows process control and has embedded this knowledge in their technology and the available libraries. The result is a platform designed to meet the unique requirements of process applications “out of the box.”   5. Safety   The use of a single controller for both standard and safety functionality: Eliminating the need for two controllers saves significant cost and reduces complexity. The optimal solution is a single controller that handles both tasks. This opens new possibilities when designing architectures such as a shared controller, shared bus system and shared I/O serving both standard automation and the safety. One engineering platform to program standard as well as safety logic: A controller that uses the same engineering tools for standard automation and machine safety configuration not only simplifies learning the tool, but dramatically simplifies the integration of diagnostic information. The same diagnostic visualization you already use for your automation system can be used by maintenance and operations to troubleshoot safety incidents. Safety as part of a distributed architecture, even with existing systems: Rather than putting in place a parallel, safety-only system, you should consider whether the safety controller can be used as a slave to the established automation system, handling the safety functions. Doing so has a significant impact on reducing integration time and effort.   6. Redundancy   Uninterrupted control of a process or machine: It may sound obvious, but redundancy implies a backup system – a safety net to protect your process from unexpected controller failures. Do you want controller redundancy only, or do you want to take redundancy to other levels? What about the power to the controller, or the networks you rely on, or the inputs and outputs connecting your process? Not only must you determine the depth of redundancy you require, but you need to determine how your application behaves during switchover. Quickly resolve a failure: When you have a failure, your redundancy strategy will keep your process or machine running. But how do you know that a failure has occurred, and how do you fix the problem? This is where diagnostic notification comes into play pinpointing the problem. Once you locate the problem, it is very beneficial to be able to hot-swap the failed components. The value of the product being manufactured and the cost of downtime: If the value of the product being manufactured is relatively low and/or downtime results in lost production but little additional cost or damage to the process, implementing redundancy may not be the best choice. If the value of the product is high and downtime not only results in lost production but potentially dangerous and damaging conditions, the nod should probably go to full redundancy. In process applications running 24/7/365, downtime is one of the gremlins you try to avoid at all cost. The more volatile the application, the more it may require a solution with lots of redundancy. Which one is right for you? With so much expected from a single controller platform, the engineering tools to support all the disciplines involved in a typical automation system become more important then the controller itself. A true multi-domain controller platform includes the multidisciplinary tools required to support traditional logic applications, as well as motion control, process control and all the other applications previously discussed. A complete suite of engineering software gives you the tools to manage the entire engineering life cycle — from design on through ongoing maintenance. Capabilities you should look for include an integrated engineering environment for logic, motion, process, etc.; a single point for system-wide engineering with a project view; a modular structured approach where you can design your automation around your process; and the flexibility provided by support for the IEC 61131-3 languages. The best controller is the one that most closely enables your automation system to meet the requirements of your manufacturing application, and allows your manufacturing process to integrate seamlessly with other manufacturing and business processes. It is important to base a controller decision on the requirements of the entire automation system … no matter what kind of TLA (three-letter acronym) is on the label. Bob Nelson, controller-marketing manager for Siemens in the U.S., has more than 20 years experience in the automation and control industry. For questions regarding controllers in Canada, contact This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Subscription Centre

 
New Subscription
 
Already a Subscriber
 
Customer Service
 
View Digital Magazine Renew

We are using cookies to give you the best experience on our website. By continuing to use the site, you agree to the use of cookies. To find out more, read our Privacy Policy.