Drives & Controls Magazine February 2023

and transfers it to a Tox pressing machine which inserts the self-piercing studs to join all three parts. After this, the robot removes the completed assemblies from the Tox machine and transfers them to unloading conveyors. The two six-axis robots both have a reach of 2,655mm, a footprint of 771 x 610mm, and a repeat accuracy of ±0.05mm. “The cell has an output of over 80,000 parts per annum with a 96-second cycle time for the three assemblies, all of which require either studs or SPRs of varying lengths or both,” says Hill. “This process used to take around eight seconds per stud, adding on time for loading, unloading, re- positioning the part and waiting for the machine. With the new cell, the operator can spend 20 seconds loading the station and then move to another task while the cell processes the parts. This reduces time and labour massively.” The second, smaller cell incorporates a manual loading and unloading station for two-part variants, as well as rivet bowl feeders for two stud sizes. A Fanuc M- 20iA/35M robot transfers the assemblies from the manual loading and Tox pressing station to the dual-feed Tox pressing station, while also selecting a suitable stud. This robot has a maximum payload of 35kg and is ideal for the application where the gripper weighs 28kg and the assembly is 2kg. This smaller robot has a repeatability of ±0.03mm and can identify the different hole positions and rivet sizes and positions before pressing the ten rivets through the holes for processing. “This cell requires four studs at the start position and another six throughout the process – all done automatically with precision, repeatability, consistency and speed,” Hill explains. “The cycle time for this cell is just 76 seconds, which once again allows the operator to load the station and do other tasks.” To help achieve the short project timescale, DForce used Fanuc’s Roboguide system to simulate both the robot’s motion and its application commands. The software can import part models and assemblies as CAD data from a PC, and includes a library that allows users to select and modify parts and dimensions. “It enabled us to design, test and modify both cells entirely offline, before and during the assembly process,” Hill reports Both cells are providing quality assurance and consistency. Manual riveting is prone to human error, but the automated cells provide consistent performance, eliminating potential operator errors, as they monitor every step of the process. “We’re really pleased this project has run on schedule,” Hill concludes. “The robots have delivered everything we have required with precision, speed and repeatability, and Fanuc’s Roboguide compressed the timescale of the project immensely. In this instance, our customer is using a different PLC system on Profinet and the Fanuc platform is Ethernet. However, Fanuc engineers supported us at every stage of the process and this further streamlined the project.” n ROBOTICS AND AUTOMATED MANUFACTURING n The two robots in the first cell work together to feed the fastening and riveting stations. The one in the background is carrying a dual-feed rivet gun. It also identifies parts and self-pierce rivets. Make it flexible. Make it sustainable. Make it OMRON. #MakeitOMRON Make the world better through creative manufacturing With our range of integrated manufacturing solutions, scale your business faster with greater flexibility and sustainability.