Robotic welding has allowed manufacturers to meet the automotive industry’s precise repeatability demands at even faster speeds than previously possible, resulting in lower costs and more advanced, higher quality vehicles. This, along with the increasing innovations in automation technologies, is driving widespread adoption of robotic welding systems.
Read below to learn when to implement advanced automated welding technologies as well as strategies that can increase uptime.
“The first thing that we want people to look at is, what are the types of parts, what is the welding process that you need to use (spot welding or arc welding), and on top of that, for those parts, are they going to be repeatable,” says Mark Scherler, general manager of Fanuc America’s material joining segment.
In automotive manufacturing, parts need to come in quickly, get welded quickly, and go out quickly. However, if they aren’t handled the same way every time, results won’t be consistent, and it’s harder for the robots to meet the necessary requirements.
There are also process requirements for repeatability among parts. A camera system checks the parts every time. Once the camera finds the part and determines how much it has moved, the system can adjust the robot’s program to calculate movement and make sure it puts the weld in the proper location.
“If you have a certain number of welding stations, you want to balance the weld across all the stations so that no robots are sitting and waiting for the next part to come due to another robot welding too much,” Scherler adds.
Next, manufacturers need to look at the size of the robot they want to use, something typically determined by part size. For spot welding, if it’s a big part, the robot needs to have more reach or needs to be able to move the spot-welding gun around and into more locations on that part. Another consideration is how big the spot-welding gun is or how much it weighs. A smaller gun can use a smaller robot. More complex applications that need big spot-welding guns require bigger robots.
“One of the main things you have to do in spot welding is sequence the welds so that as a part moves down an assembly line, each robot does the same number of welds and the part goes into the first station and it gets let’s say 10 welds, and then it goes into the next station and gets 10 welds,” Scherler says. “That balance of all the welding that you are doing is organized and is consistent for every robot, and you don’t have one robot that becomes a bottleneck.”
Factors to consider
Since automotive manufacturers are using aluminum and other new materials, special considerations are needed, explains Mark Anderson, head of robotics and automation products at Comau. Thinking through coatings, part cleanliness, part setup, and what type of repeatability is expected can ensure that it’s suitable for robotic welding.
When determining setup and repeatability, establish how well the anticipated joints fit together – what type of gaps need to be accounted for in the joint before it’s welded. Repeatability of the joint location must be considered as well.
“When a vehicle is welded together in the end, you have to account for the worst case,” Anderson says. “So, if you have 10 parts and all the parts were at their maximum range of allowable tolerance, and then you assemble them into one unit, how well do they fit? Are the welding joints on the unit suitable for the welding process?”
Integrators also need to consider if the robot’s size is suitable for the intended application. If choosing between a small or large-reach robot, look at the expected throughput.
As Yaskawa America director of thermal business development Zane Michael puts it, “If the customer wants 10 parts an hour, maybe one robot can’t do that. You might have to put three robots in the same area. And, in the automotive industry, you see a lot of robot density – high robot density for the space given. When we look at a line or a cell to produce an automotive component, we need to understand the throughput requirements to determine the number of robots.”
Within production, most daily maintenance will be related to the process performed by the robot. To maximize uptime, manufacturers should monitor those items’ use and wear. For example, manufacturers can monitor the health of their spot-welding gun by examining the tips on the device. After so many welds, the device needs to go to a maintenance station to regrind tips to proper shape. This process can be automated with a tip dress, Scherler explains. Automating tip regrind and cap replacement can boost uptime, allowing work to be done while parts transfer between weld stations. In arc welding, the process generates spatter, and proper maintenance can ensure that the spatter does not build up on tooling or the torch.
“You can automate the torch cleaning station that will clean that welding torch,” Scherler says. “Generally, as your tooling builds up with spatter, it could get in the way of tools getting loaded automatically. It could cause the parts to get loaded out of position and affect the resulting quality of the weld. You need to schedule maintenance to clean off your tooling.”
Other components within the robot, including batteries and grease, can also be scheduled for maintenance.
Robotic automation accessories ensure the weld joint is in a flat position. Some components should be welded overhead or vertically. A seat back or axle assembly, for example, should be welded in a robotic cell, where the weld joint is flat or horizontal. Many welding positioners are available to do this. When selecting a suitable positioner, the user should ask, do I need to rotate the weldment? How heavy is the load that I must move or hold?
“At Yaskawa Motoman, one of our many positioners is called the Ferris wheel,” Michael says. “It will take the unwelded parts to the robot, and then the welded parts that are on the robot side come out to the operator, where the operator unloads and reloads.”
It is also key for operators to not overlook the performance of their process.
“The goals of automating an application are typically to improve safety, product quality, and increase uptime so that you can have a process that is efficient and cost-effective,” Anderson adds. “In an effort to reduce the meantime to repair, we are driving our products to have interfaces that are simple and easy to use. Comau's cross competency platform in.Grid provides real-time monitoring of equipment and systems, which enables predictive maintenance, analytics, and condition-based maintenance.”
Incorporating Industrial Internet of Things (IIoT)/Industry 4.0 modules, such as a central dashboard to look over a factory, will allow manufacturers to understand the health of their equipment. These types of tools can alert operators of possible failures and provide insight about how to fix the problem or stop a potential issue from occurring.
Magswitch switchable magnetic gripping and clamping solutions for automotive original equipment manufacturers (OEMs) last throughout a production line’s lifetime. Energy costs are 90% lower, throughput increases up to 30%, and capital costs fall 25% compared to systems using vacuum cups and pneumatic/electric grippers or clamps.
The solutions can be applied to press lines and stamping operations where switchable magnets handle lubricated sheet metal blanks. In assembly and body-in-white applications, the magnets offer the versatility and simplicity of suction cups while maintaining the reliability and safety of traditional power clamps. With single-sided clamping, Magswitch tools perform faster during welding, and when integrated with vision systems, the tools streamline bin picking and handling randomly arranged components.
In machine tending and pick-and-place applications, switchable magnetic end-of-arm tools reduce cycle times. Separating ferromagnetic sheets with Magswitch sheet fanners and variable flux systems decreases downtime and enables double blank detection.
E3AS series reflective-type photoelectric sensors have a 50mm to 1,500mm sensing distance to detect diverse targets, eliminating the need for manufacturers to select different sensors for each application. The time-of-flight (TOF) detection method ensures high detection stability regardless of the characteristics of target objects.
Antifouling coating reduces false detection and minimizes maintenance needs in environments with oil, dust, or steam.
Extending the reach, footprint of industrial robots
Lifkit, Slidekit linear motion modules have a telescopic pillar that can raise and lower a standard robot or cobot up to 900mm.
For horizontal extension, the Slidekit can increase each robot’s reach up to 1,800mm. A standard Evellix’ profile rail guide, combined with an advanced ball screw, ensures accurate positioning and repeatability.
Lifkit and Slidekit can be combined and are available as plug-and-play solutions for use with all robots from Universal Robots (UR).
Automated laser processing
The multifunctional Lasorting automated laser machining system controls the entire production process from loading, cutting, sorting, and unloading to storage of finished parts.
The system uses four Cartesian grippers for loading, unloading, and part sorting. Each gripper uses various vacuum or magnetic tools for a faster sorting. The process sorts the parts into kits, and various of options allow different material thicknesses to be kitted on the same pallet.