Welding and Robotic Automation

Robotic automation has been heavily used for welding applications for years now, as evidenced by numerous commercial solutions available in the market. Over time, fabrication engineers have amassed deep expertise in using these technologies to maximum effect. Yet the needs and expectations of industry continue to change.

One of the most basic goals of robotic welding applications is to produce shorter cycle times. Shave off a few milliseconds here and there, and you can gain significant savings when the lot-size is big enough. Besides cycle time, there is the constant need to adapt to, incorporate and accommodate brand-new technologies that advanced manufacturing brings along—innovative materials, complex forms and pioneering applications.

Offline programming (OLP) is key to staying on top of such challenges and moving ahead with robotic automation, and we will explore the reasons why. Lately, though, the industry is realizing that while the success of automation relies on powerful tools like OLP, it needs more than the technology alone. That factor is the creativity, experience and essential knowledge of those on your shop floor—and how you apply it to the new order.

Powerful robotics requires powerful programming

Assembly Magazine quoted the International Federation of Robotics as saying that half of the world’s industrial robots are used for welding. Spot welding robots account for 33 percent, and arc welders add another 16 percent. The majority of these welding robots are mature products that have been perfected over time by manufacturers like Yaskawa/Motoman, Fanuc, Kuka and Kawasaki.

Regardless of who builds the robots, one of the key success factors is how the programming is handled. To program welding robots to efficiently and produce a quality product, fabricators need powerful 3-D layout (3DL) and offline programming software. By using the right software and the CAD data for the part to be produced, programmers can configure the robot’s torch angles, arm configurations, feeds/speeds, power settings and more, to create optimal welding schedules.

The need for 3DL capabilities is evident, but why OLP? As the name suggests, offline programing is done offline (that is, without having to take your robot cell out of production mode). You can configure the new production parameters, then optimize and verify them, all through OLP—regardless of the dynamic process requirements. Then, the new process can be implemented and controlled with an automated system. With 3DL and OLP software, therefore, you get the perfect equilibrium between high quality welding and lower cycle time.

Adding new cells needn’t disrupt production

That perfect balance is good news for your management, if you’re the one setting up the changes in the fabrication. This is especially true if your success leads to increased demand for new cells, new workpieces and product configurations.

However, programming robots—the practice of teaching a robot the various points, trajectories and joints to use on a workpiece—can take days or weeks, depending on the size and scope of the workpiece and the cell itself. Taking a cell offline for weeks—leaving your latest-and-greatest robot idle—means a deep cut in productivity and profitability.

Let’s say your automated production has been so successful that you need to make room for more cells. One of the major costs of installing automation is disruption of ongoing production. If you assume you must take a cell offline each time you need to change its output, you must include the cost of lost production when calculating the investment of adding new welding cells. It is therefore imperative to reduce installation time on the factory floor as much as possible.

As before, your software can help minimize the disruption and its associated cost. OLP software lets you de-couple the programming and validation efforts from the installation schedule. By finishing all the robot teaching prior to physical installation, production can begin almost as soon as the system is powered up.

Compare that scenario with the typical manual approach to robot teaching, where the programming doesn’t even begin until after the entire system has been installed and production parts are available.

How does 3DL and OLP software optimize your cell design?

As automation expands beyond basic welds into more advanced tasks, its availability also expands beyond large manufacturers. Today, the use of robots for fabricating non-traditional parts is within reach of small- and medium-sized manufacturers. Robotic systems can now perform advanced, high-quality welding tasks for both standard and non-standard parts, including multi-pass welds, stitch welds and a variety of weaving patterns. To handle more complex welding tasks for more and more manufacturers of all sizes, integrators need to speed up installation while maintaining an error-free design.

Here again, a key technology in successfully implementing these tasks is software for 3-D off-line programming and simulation. System integrators use 3DL and OLP software to achieve the optimum system design. Starting with an accurate model of the factory space, an integrator can design the automation system to fit within physical constraints, such as building columns, low clearance structures and existing work traffic lanes. They can also include the critical utility connection points in your model.

OLP software allows the integrator or programmer to create, try out and refine robot trajectories in a virtual 3-D space, prior to installing equipment on their factory floor. It also lets users deal with complex geometries and find the optimal robot paths to perform welding operations. This ensure the robot avoids obstacles and can navigate through tight spaces—either due to complex tooling or the part itself—all while maintaining the necessary torch angles and avoiding collisions between the part, robot arm and torch.

Read more in FASTSUITE EXPERTISE.