Laser coating process slashes manufacturing costs of electrical contacts

September 23, 2018 // By Christoph Hammerschmidt
Laser coating process slashes manufacturing costs of electrical contacts
Electrochemical coating processes for precious metals on electrical contacts require a high input of materials and energy and cause environmentally harmful burdens. In a research project, the Fraunhofer Institute for Production Technology IPT is working with project partners to develop a new system for laser deposition welding of gold onto electrical contacts. The laser coating process will significantly reduce gold and energy consumption and avoid toxic substances.

In conventional electroplating, the contact components are coated in an electrolytic process that releases environmentally harmful substances. This complex process does not permit direct integration into the extensive stamping-bending process chain for the production of electrical contacts. This results in high production costs for the transport route to the galvanic plants, for energy and raw material consumption as well as for waste water treatment.

In deposition welding, on the other hand, the laser efficiently melts gold droplets from several micro wires and requires no electrolyte with toxic compounds. Point by point, the relevant contact area is coated with the necessary amount of precious metal. The required gold volume can be significantly reduced overall by applying the coating with pinpoint accuracy.

The feasibility of the laser process for coating electrical contacts has already been demonstrated in an earlier project. This also showed that the new process not only reduces the use of gold by 84 percent, but also significantly reduces energy consumption at the same time.

In the GeCo project, the Freunhofer engineers and their partner companies now want to implement a stable coating process as an alternative technology to electroplating. Manufacturers of stamped components, electrical contacts and coating companies benefit from laser deposition welding by producing more cost-effectively and environmentally friendly.

During the project, the mechanical performance of the coating is ensured by long-term tests. The gold spots must be reliably welded to the contact point so that their electrical conductivity and high wear resistance, for example after a certain number of load cycles, are maintained. An inline quality control system is therefore being developed for quality assurance of the coating process. The gold points are to be monitored for their correct number and position intervals using image processing software.

Until now, the galvanic process did not fit seamlessly into the rapidly clocked punching and bending process chain. After punching, the manufacturers of conductive contacts must roll up the sheet

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