From tooling to training: Best practices for welding automation
May 13, 2014 by Kevin Summers
Implementing welding automation can be a daunting task, especially for first-time purchasers. From justifying the capital expenditure to determining space requirements for the robotic welding cell and ensuring parts are suitable for the operation, every detail is critical. When done properly, however, these steps can lead to drastic improvements in productivity, quality and cost savings compared to a manual welding operation. A robotic welding system also offers companies a competitive advantage over those that have not made the shift to welding automation.
Gaining the desired results from welding automation doesn’t happen by chance, though. It is important to follow best practices throughout the process to gain the best efficiencies and a desirable return on the investment. Establishing proper workflow, employing the right tooling and assessing the parts are just the beginning.
The most efficiently programmed robotic welding system means nothing if the parts it needs to weld don’t reach or leave the cell in a consistent manner. The layout of the facility, as well as the manner in which employees handle parts, can often create bottlenecks in the upstream and downstream operations that negate the benefits sought in welding automation.
As a best practice, companies should always look carefully at the steps involved with bringing the parts to the robotic welding cell and determine the best course of action for handling them after the robot finishes welding. In some cases, it may be necessary to reconfigure an existing operation or change the manner in which parts are fabricated upstream and completed downstream (e.g., finishing, painting, etc.). Companies may also need to assess the way employees supply parts to the robot to ensure they can match its cycle time.
The goal when establishing a good workflow is to eliminate any non-value-added activities — those activities that do not add to the overall productivity of welding automation — including unnecessary transporting, lifting or handling of parts. Omitting these activities can be as simple as changing the way an employee removes the parts from the tooling, minimizing the distance he or she walks to place them on the pallet or creating an alternative way of stacking parts.
Pay attention to part design and fit-up
Designing parts up front for welding automation is critical, as is ensuring proper part fit-up. Complex parts or those with large gaps, fit-up or access challenges do not lend themselves well to a robotic welding system and are best left to a welding operator who can weld in obstructed or precarious positions and compensate for such conditions.
As a best practice, make certain that the parts intended for the robotic welding system are simple and repeatable. If there is a mature part that was originally welded manually, look for ways to change the part design to make it easier and faster to weld with a robotic welding system while still preserving the part’s function. For parts that are new to automation, look for ways to build efficiencies into the design from the ground up. A careful assessment of a part’s blueprint or electronic CAD drawing is a good start.
New and innovative advances in offline programming also allow calculation and experimentation of designs from a computer workstation before ever touching the actual part. This type of programming gives the confidence that changes in the part really work. Once complete, these design changes can be exported directly to the robot to help improve productivity and efficiency even more.
In addition to ensuring proper part fit-up when first implementing welding automation, it’s also critical to assess it in the days, weeks and months following. Normal wear that occurs on a die, for example, can lead to slight variations in the parts that it produces and in turn affect the way the parts fit together. Any changes in the raw materials being used to form the part can have a similarly negative impact.
Ultimately, if a company doesn’t take the time to address poor part fit-up, it can lead to overwelding — a source of significant and unnecessary cost in both labour and materials, particularly filler metals — and/or it may cause poor weld quality, which can lead to downtime for rework.
Use the appropriate tooling
Using tooling suited to the volume and variation of the parts being produced in a robotic welding application is essential to ensuring good quality and high productivity. In addition to securing the parts so the robotic welding system can execute consistent welds, the proper tooling can also have a measurable impact on the comfort and efficiency of the operators overseeing the loading and unloading of parts.
Job shops and small manufacturers tend to have a low volume and high mixture of parts, which typically means that tooling with basic manual clamps will be adequate for the job. Or in some cases, these companies may want to use a modular style of tooling that can offer more flexibility for welding a variety of parts.
For companies that weld a higher volume, lower variety of parts, however, more sophisticated tooling can bring significant benefits. Consider tooling with automatic clamping capabilities. Not only does it help minimize downtime for manually clamping what could be thousands of parts over a relatively short period of time, but it also minimizes fatigue and ergonomic problems for the operators who load and unload parts. Automatic clamping for high volume production can also minimize potential mistakes that can come from that fatigue — clamps left open, for example, that could lead to a collision or missed weld joint. An added benefit of automatic tooling is safety, since the operator closes the clamps via a palm switch or other such external output at a distance from the tooling.
Implement weld management programs
Weld management programs are an excellent way to gain positive results from a robotic welding system. These programs allow companies, among other things, to track the parameters of individual welds, determine the cause of weld defects and identify general inefficiencies to rectify those problems and optimize the process for peak quality and productivity. Most often — and producing the most effective results — weld management programs are integrated into the power source. In some cases, companies can utilize this software by way of third-party integration, but companies run the risk of employees turning off these latter devices, making the investment ineffective.
At a base level, the goal of any weld management program is not just to provide data, but rather to provide actionable data — information that can help the company predict and rectify potential problems that could lead to downtime and additional costs. In fact, this software can even assess the actual downtime that occurs within a robotic welding cell over the course of its cycle time.
Additionally, weld data management programs can help companies track consumable usage to implement changeovers during routine pauses in production, and they can help identify ways to improve weld quality. These programs can also help address the incidence of overwelding, which causes the company to incur unnecessary costs.
Don’t neglect maintenance
Implementing a preventive maintenance (PM) program is among the easiest and most important best practices to protect the investment in welding automation. PM programs should cover not just the robot, but also the robotic MIG gun, consumables, cables and peripherals.
Scheduling time to check connections throughout the system, clean fixturing (to prevent debris that may affect part fit-up) and confirming tool center point (TCP), for instance, help ensure that the robotic welding system continues to operate within its proper parameters. Usually, it is possible to schedule maintenance during routine pauses in production. There may be some activities, however, that occur less frequently and must be completed during a longer scheduled stop.
Companies need to assess their individual needs, ensure their maintenance team has the proper training and plan the preventive maintenance schedule accordingly. Neglecting maintenance can lead to unscheduled downtime, poor quality parts and/or costly repairs. It may even lead to failures that require equipment replacements.
Find the right people
Investing in the people who are responsible for overseeing the robotic welding system is just as important as investing in the equipment itself. Quality employees who clearly understand not only the operation of the system, but who also recognize the benefits of a robotic welding system, are critical to the success of the operation.
These individuals need to undergo the proper up-front training before taking on the responsibility of working with the robotic welding system — loading and unloading parts, programming the robot or overseeing its maintenance, for example. Typically, robotic integrators can offer OEM-based training, as can robot manufacturers. Beyond this training, however, it is critical that the employees involved with the robotic welding system be committed to continuous improvement of the operation. That commitment helps the employee become a more valuable asset to the organization and helps put the company in a better position to grow, expand and thrive in an increasingly competitive global market.
Best practices bring the best results
While there are many facets to implementing and operating a successful robotic welding operation, following some key best practices can go far in establishing high weld quality and productivity, as well as a solid return on the investment in welding automation. For the sake of continuous improvement, companies should invest in the personnel and training necessary to make the process easier, faster and more efficient. After all, robotic welding systems don’t operate autonomously — the human element is still a significant factor and one that is integral to creating proper workflow, implementing effective maintenance programs and creating parts designs that can lead to the best performance and profitability.
Kevin Summers is an automation specialist, welding automation, with Miller Electric Mfg. Co.