In many low torque assembly operations, simple clutch screwdrivers are still used for the majority of tightening performed. These screwdrivers have been used for years in industries such as Electronics Manufacturing, and provide the most basic level of error-proofing: a clutch is set to shut a tool off when the correct amount of torque is achieved. The clutch action tells us that the joint is tightened to the right level.
In low torque assembly, however, that basic level of error-proofing is often not enough. In many applications today, screws are assembled into plastic holes, and threads are cut into the hole during assembly. The challenge with these self-tapping applications is that the size of the molded plastic hole can vary, and with that variance, the amount of torque needed to cut the threads into the hole changes from screw to screw. If more or less torque is used to cut the threads, then the amount of torque used to make the assembly acceptably tight also varies. In some cases, the difference can be extreme enough that an assembly is not only not tight, but the screw is still standing up out of the hole (“floating”) when the clutch tool shuts off.
In addition to the possibility of floating screws, assemblies are becoming more and more complex. In the Electronics industry, products contain more screws and more small parts being assembled into a final product than ever before. This complexity presents challenges for the operators tasked with putting these assemblies together. It can often be difficult to verify if all fasteners have been tightened, if the correct screws have been used, and if everything has been assembled accurately.
A key part of any solution that addresses these problems is a more sophisticated tightening system. The Atlas Copco MicroTorque Focus 6000 (MTF6000) tool controller and associated tools and accessories can be used to error proof the challenges of a low torque assembly environment.
- The Seating Control Strategy, available in the MTF6000, gives us the ability to detect when a screw has seated, and then tighten it to the correct level. This eliminates the possibility of floating screws or stripped threads.
- Features such as batch sequencing allow us to count the number of screws being assembled, to make sure that no screws are missed in an assembly process.
- Accessory items such as vacuum screw pickup devices, screw presenters and position recognition systems can ensure the correct screws are being assembled in the correct location, every time.
- For more advanced operator guidance, we are able to add our SQS process control software, giving operators dynamic work instructions to follow, along with the process they are running.
Low torque assembly has never been more sophisticated, and fortunately, Atlas Copco can provide a family of products to meet those challenges not only today, but into the future as well.