Tightening systems Zero-error strategy for electronics assembly
Markus Stops, Produkction Manager of EA Elektro-Automatik GmbH & Co. KG
„We have achieved a 30 percent productivity boost. Thanks to the additional torque and angle monitoring functions, we have significantly improved quality.“
Nowadays, every electrical laboratory and every research institute needs unidirectional and bidirectional DC power supplies as well as regenerative DC electronic loads,” says Markus Stops. “These units are essential for testing vehicle electronics and high-voltage components of all types. The increasingly important tests connected with e-mobility would also be impossible without this equipment,” says the Production Manager of EA Elektro-Automatik GmbH & Co. KG (EA) in Viersen, explaining the importance of these relatively inconspicuous high-tech units that are only 19 inches high. Looking at the compact white metal housings of these power supply units, it is by no means obvious that they return 96 percent of the energy they use to the grid after they have done their work.
96 percent efficiency
EA is regarded as the inventor of regenerative electronic loads; most recently, we have been able to reduce the power loss to only four percent,” explains the Production Manager with some pride. He says that this is a world-class achievement, saves costs and also avoids the need for complex cooling systems. However, Markus Stops admits that you cannot see from the outside that each of these units contains up to 75 joints that are function- and safety-critical. He says that the correct tightening of these joints with the precise torque value is absolutely essential. If only one joint fails, an entire plant may be out of action. To ensure the required quality, EA had previously inspected each individual joint, Stop reports, as he guides us through production. The degree of manufacturing depth at the plant is very high and the company assembles the circuit boards and manufactures entire components at the plant, also carrying out comprehensive testing and final assembly. “We use our best efforts to maintain our skills by keeping the manufacturing depth within the company as high as possible and keeping up with the state of the art with all key production steps,” the Production Manager emphasizes.
Monitoring to eliminate errors
As a recent example, Stops presents the changeover to entirely new tightening tools in assembly. “To achieve maximum process security and quality, we wanted to ensure seamless monitoring of our assembly processes and to evaluate the tightening data. This way, we can use the data for further quality improvements. However, the cordless tools we had used previously would not have supported this approach. This is why we accepted the offer of our tool supplier Tools-Technik-Gilges to try out an innovative MicroTorque system from its partner Atlas Copco Tools.” This system was to significantly reduce the work required for testing critical joints; following successful completion of trials, it would even be possible to eliminate these tests.
An easy start
“The commissioning of the first unit was already extremely easy and intuitive,” says Frank Schriefers, Deputy Head of Production at EA: “Using the soft buttons on the MicroTorque controller, I was able to set the torque of 100 Newton-centimeters required for our electronic loads and the ideal speed in a few seconds. Programming via the controller is much more precise and convenient than the mechanical setting and measurement of torque at the shut-down couplings of our previous battery tools.” In contrast to the old tools, the MicroTorque screwdrivers, which measure torque directly with an electronic transducer, operate considerably more precisely without any sensitive mechanical systems.
The tool thinks for the operator
“According to the manufacturer, as soon as the MicroTorque system has been programmed to meet the customer’s individual assembly requirements, it becomes practically impossible for the operator to make any errors. “The tightening torque and tightening angle for each individual joint are monitored. This means that the possibility of incorrectly tightened screws is excluded,” Schriefers reports. If a screw with stripped threads is installed or the operator releases the starter lever of the tool too soon, the MicroTorque system immediately initiates an alarm and requests the operator to remedy the problem. In addition, the integrated batch counter means that the screw cannot be simply forgotten in the assembly sequence, report Frank Schriefers and Markus Stops, confirming their positive operating experience. “The counter function supports the operator and makes the process more secure. The smart monitoring system also means that we no longer need downstream testing.“
Smart connected utilization of assembly data
Thanks to the consistent monitoring of torque and angle, no incorrectly assembled modules can leave the production station without being detected and EA Elektro-Automatik GmbH & Co. KG has gained additional security through the Atlas Copco system with documentation functions. Using the data acquired, the Viersen electronics manufacturer can quickly demonstrate that each joint was tightened precisely in accordance with the specification during production if a problem later arises. For this reason too, Stops and Schriefers already decided after a very short space of time to use five more ESD-certified Atlas Copco screwdrivers approved for clean room use at their production facility..
30 percent productivity boost
“The system met all our expectations as regards ergonomics, quality and process security. We have now changed our entire production facility over to MicroTorque equipment,” Marcus Stops emphasizes. “Thanks to the easy handling of the flexible system and the elimination of testing steps previously required, we have been able to improve the overall productivity of our assembly facility by an impressive 30 percent,” the EA Production Manager is pleased to report.
You will find further impressions in our video: