When it comes to assembly operations in automotive—at the OEM or supplier level—robots have become a way of work. Arguably, this is one area where robots have come to the fore more than almost any other application with the exception of body painting. If you think about it: Chances are the last time you saw someone with a spray gun in a factory painting cars was approximately the last time you saw someone wielding a spot welding gun welding unibodies. With time, there have been improvements in the capabilities of the equipment, allowing more types of welding as well as providing the ability for mechanical assembly.
Here are a few examples of some relevant tech that you should be aware of in the assembly robot realm.
One of the things that robot “arms” have long been associated with are, well, arms. Yet most robot systems have a single arm. People have two. So Motoman figured that they might as well mimic what evolution has come up with as a solution and thus the SDA robot family. There are three members of the family. The SDA 5 with a 5-kg capacity; the SDA 10 with a 10-kg capacity; the SDA 20 with—you get it. The horizontal reaches are also relative to size: 1,690 mm, 1,970 mm, and 2,590 mm, in order of SDA 5, 10, 20. Each of the robots offers 15-axes of motion, 7 per arm and a main rotational axis. One of the advantages of the two-arm approach that Motoman cites is the ability to perform more complex assembly, as both arms work in coordination. Thanks to the dexterity of the robot design, it is possible to simplify tooling for assembly (e.g., one arm might hold the workpiece while the other performs the assembly task).
Some people might be thinking to themselves “Denso . . . isn’t that the name of an automotive parts and systems supplier?” And the answer to that question is, “Yes.” And it is a case where the company needed some specific technology—like robots—to do its tasks, so it developed them. The VM series is a result. These six-axis arms have a 13 kg payload capacity. The long, slim arms offer reaches from 1,000 to 1,300 mm. They have a high maximum allowable moment of inertia that is claimed to be 2.5 times greater than competitive robots (e.g., 0.36 kgm2 at J4 and J5 and 0.064 kgm2 at J6). Standard cycle times are 0.89 to 0.95 sec. The repeatability provided is from ±0.050 to ±0.070 mm. The assembly tasks that the robots can be used for include spot welding, laser welding, ultrasonic welding, soldering, adhesive dispensing, nut running, and more.
The R-1000iA robot is a compact, high-speed, six-axis robot with an 80- to 100-kg capacity and a 2,230-mm reach that has a slim profile design and large operating space that lends itself to applications including spot welding. The “Gakushu” part is a technology that’s available for the robot that increases the speed of the arm while maintaining smooth motion. This is beneficial in times like product launches as well as to address bottlenecks in existing operations. The way it works: a sensor is mounted on the end of the arm so that information about the operating conditions is collected during several runs of the sequence. The sensor is removed. The information is then used to increase the speed of the program while minimizing any vibrations in the tool. Programs developed in this manner can run up to 20% faster than is otherwise the case—even without an expert programmer’s involvement.