Welding sheet metal is a very common application in traditional automated production. In the automotive industry, the spot welding of sheet steel dates back more than 60 years. But what about aluminum? Lightweighting is essential in automotive processes, especially for heavy trucks. In this video, watch an automotive welding cell working on a heavy truck application; specifically, an aluminum tailgate for a dump truck.
Josh Leath, product manager of welding at Yaskawa, gave us the details on this impressive robotics application.
Armorlite Trailers, the customer associated with the demo featured in this video, was interested in aluminum because of their need for lightweighting. Aluminum has strength and the light weight Armorlite required, but this material is notoriously hard to weld with automation to the same specification as hand-operated TIG welding.
In this demonstration, a Yaskawa 3120 arc welding robot is installed with a Fronius power supply. This is one of the best power supply options for aluminum on the market today because it is capable of “TIG-like cosmetics,” according to Leath. “It’s something we will continue to experiment with. The aesthetics and strength continue to get better.”
Readers not familiar with automated welding may be wondering: if the robot can easily access any angle and path within its reach, why use a positioner? The reason is to make as many welds as possible in a horizontal position, which will help produce a better-quality weld.
The workpiece is mounted on a scalable positioner, capable of adjustment from 2 to 5 meters. A cell like this can incorporate a single robot, or two robots working in tandem. The positioner can also be configured as a two-sided system, with an operator loading parts on one side as the parts are welded on the other side, reducing cycle time.
Three meters, as shown with the 3120 robots, is the longest reach available. This is the largest of the potential cells within Yaskawa’s standard line. The Yaskawa 1440 robot has a meter and a half reach. Therefore, two 1440 robots side by side could increase cycle time by welding simultaneously. However, this cycle time gain must be evaluated against the additional cost of that second robot.
The robot arm is calibrated to work together with the positioner. The controllers are capable of ‘talking’ to all these axes at the same time, so the robot can maintain an accurate place on the part while positioner rotates the part to hit all the different angles.
Pre-engineered or Custom Designed?
Customers interested in a cell like this, whether from Yaskawa or any other robot maker, should carefully consider the choice between custom-integrated and pre-engineered cells. Pre-engineered cells can typically provide a better ROI, thanks to their faster speed of deployment and because the engineering has all taken place before the end purchase. Pre-engineered cells are tried and tested, and purchasing one allows the customer to sidestep the integration and design headaches of a custom solution. However, not all applications match neatly with the pre-engineered options available. Most robotics companies have engineers on staff that will work with customers to determine the best solution on a case-by-case basis.
The cell on display in this video is one of Yaskawa’s standard, pre-engineered configurations. According to Josh Leath, if the customer’s needs require more scalability, size or workpieces over 1000 kilograms, Yaskawa can design that for the customer in-house.
“We also work with a large network of integrators to deliver standard and highly modified and custom cells,” Said Leath. “For one customer, we used a combination of three robots on tracks welding in four different cells which converge into one ‘monster cell,’ if you will. The cell does four processes simultaneously, all while welding large truck bed.”
Lastly, one of the most important things to consider when building new automation into your welding process is the programming. Some robots can be programmed by dedicated robot programmers, who can achieve a high level of efficiency in motion paths and optimization. Other robots, such as Yaskawa units, are designed to be intuitively programmed by non-expert staff.
This means that your highly-skilled welders may be able to transfer some of their expertise onto the robot, achieving an even better final product. Whatever your situation, automation brings many important trade-offs to consider.
For more on pre-engineered welding cells, check out VIDEO: Pre-Engineered Cells Simplify Turnkey Automation.