Case study: Start the presses
March 10, 2010
By Manufacturing AUTOMATION
A Canadian boxboard manufacturer is at the forefront of making high-speed equipment safe, with help from Rexroth’s innovative Safe Motion technology.
You don’t want to mess with a die cutter.
“It’s probably the most vicious thing you can imagine,” says Corey Mackenzie, Electro-Mechanical Engineering Technologist with the Cascades Boxboard Group, a division of Cascades Canada. “It moves at almost 6,000 RPMs, running around the speed of a household blender. If you got your hand in there, it’s not going to be an injury you walk away from.”
That’s why safety is the number one priority at Cascades’ plant in Cobourg, Ontario, Canada. The plant prints cereal boxes, coffee cups and packaging boxes for a number of different consumer goods. Their presses and die cutters must work at high speeds, cutting the products in perfect synchronization.
But those speeds don’t always equal safety, and that just isn’t an option for Cascades.
“There is no way, at the end of any shift, Cascades, from the Corporate level on down, want anyone of our employees to get hurt” says Eric News, plant manager of the facility. “Truly responsible management must take that into account. You should be taking every precaution along the way.”
That doesn’t mean productivity and safety have to be mutually exclusive. The team at Cascades recently learned that new technology exists to allow them achieve the speed and productivity they need, while still providing the utmost safety for operators.
The discovery started after Cascades purchased a used high-speed printing press from a company in England, and needed to retrofit a die cutter onto the line. They arranged for an integrator from the United States to integrate the die cutter with the press, but when the system arrived, they discovered it wasn’t going to be up to the challenge.
A need for speed — and safety
When it came time to integrate the die cutter system with the press, Mackenzie found that two major issues arose. One was that the drives were too slow for the press to be able to reach top speeds, even though it was a new drive and control system.
“It didn’t have any functionality and the drives were erratic,” he says.
The drives were meant to synchronize the die cutter with the printing press, but the drive system simply couldn’t keep up with the press.
The second challenge was safety. Because the die constantly cuts boxboard and cardboard packaging, residue builds up. To clean it, operators would have to stop the machine, clean part of the die, re-engage the machine, rotate the die, turn the machine back off, clean another section, and so on until the die was cleaned. The time-consuming process not only caused downtime, but there was potential for an operator to disregard the rules and not turn the machines off in an effort to speed up the process.
The system also uses small cameras to make quick adjustments to the dies, and those cameras need periodic adjustment and cleaning. Operators have to be allowed into the area while the machines are running — something the original drive system was unable to allow.
Mackenzie came to the conclusion that the control system they had ordered to help integrate the press and the die cutter just wasn’t going to work.
“We took that control system and, basically, threw it in the garbage,” Mackenzie says. “We said, ‘we’ve got to make this a lot safer for our employees.’”
A true integration
Mackenzie and News turned to a local Bosch Rexroth Certified System Integrator, Automated Products and Supplies (APS) to help resolve those two major challenges. Mackenzie worked closely with APS’s Trevor O’Meara to find a new drive system that would allow the press to reach top speeds and integrate both safety and ergonomics.
O’Meara, too, understood how important it was to integrate safety into the control systems. “Safety is legislated, mandated and monitored in this country,” he says. “If you don’t have safe equipment, you have to upgrade it to be safe by the new standards.”
The first step was to install new drives — this time choosing ones that were properly sized to ensure the press could reach full speeds. O’Meara and Mackenzie worked closely with Bosch Rexroth Canada’s engineers to select a 3 axis Rexroth IndraDrive system with Synax control.
With the drives now able to bring the press up to speeds of approximately 1,500 feet per minute, it was time for Mackenzie and O’Meara to turn their attention to safety. Allen Rutherford P.Eng, senior applications engineer with Bosch Rexroth Canada, had the answer: safe motion.
Bosch Rexroth’s Safe Motion technology provides advanced safety functions that Cascades could integrate directly into the IndraDrives. The Safe Motion technology complies with the latest international standards for safe stopping and safe motion.
The team implemented Rexroth’s IndraDrive based Safe Motion technology, enabling all three axes to stay powered up but still lock out safely. It allows operators to get into the machine and make the needed adjustments without shutting down the power.
The great teamwork and cooperation between Cascades, APS and Bosch Rexroth, along with Rexroth’s easy to apply Safe Motion technology, resulted in a successful upgrade.
“The black-box external type of safety system can cost big money and be a nightmare to commission,” Rutherford says. “This commissioning was very easy since there is no programming required. We simply parameterized the Safe Motion parameters and in four hours the system was up and running.”
Full speed ahead
Once the new press and die cutter were properly integrated, and the drive and control system was up and running with Safe Motion, Cascades was soon able to realize the benefits of the installation. Those benefits include:
• Increased speed and decreased product rejects. The new motors and drives are sized more accurately, which Mackenzie says helped them increase the speed of the press and decrease the amount of product rejects. The Synax synchronization system from Bosch Rexroth also helps the press and die cutter work in tandem to ensure a perfect product almost every time.
• Increased productivity for operators. The system’s Safe Motion gives operators access to the machine for adjustments and maintenance without having to turn off the power, which saves time for the operators. And the less time it takes to adjust or maintain the machine, the more time that machine can be running.
• Engineered safety in the control system. The new system no longer has to rely on operators performing in a safe manner. With Safe Motion, safety is integrated directly into the press and die cutter, making it virtually foolproof. “If the operator has full access to his machine and can make adjustments, his job is a lot easier,” Mackenzie says. “He just has to worry about making the right adjustments. He doesn’t have to worry about getting in there safely.”
In the end, Cascades found it could have both safety and performance without compromising a thing. “In this case, you can have your cake and eat it too,” says News. “You can create the safest possible environment you can, and still improve productivity.”
Bosch Rexroth Canada is the Canadian partner company of Bosch Rexroth AG, one of the world’s leading specialists in the field of drive and control technologies. Under the brand name of Rexroth the company supplies more than 500,000 customers with tailored solutions for driving, controlling and moving machinery used in industrial and factory automation as well as in mobile applications. Bosch Rexroth is a partner for industrial applications and factory automation, mobile applications and using renewable energies. As The Drive & Control Company, Bosch Rexroth develops, produces and sells components and systems in more than 80 countries. In 2008 Bosch Rexroth AG, part of the Bosch Group, achieved sales of around 5.9 billion Euro with 35,300 employees.
For more information please visit: www.boschrexroth.ca