Raschig GmbH of Ludwigshafen and LPKF Laser & Electronics AG have developed new high-performance LDS materials based on thermosetting epoxy resins in a joint pilot project. The impetus for this project was provided by the fact that copper and the thermoplastic LDS plastics, especially the partially crystalline materials PET/PBT, PA 6/6T, and PPA, exhibit different thermal expansion coefficients.
 
There can often be abrupt changes in the glass transformation range – leading to adverse effects on the adhesion of the metallization layer and hence the reliability of the MID component in thermal cycling conditions. This is where liquid crystal polymer with a similar linear thermal expansion coefficient to that of copper shows its suitability. However, the relatively high price of this material limits its economic feasibility for some large-scale applications.

The newly developed high-performance LDS materials are expected to contribute to allowing economical manufacturing of MID components using laser direct structuring with lead-free solder. There are currently two materials available from Raschig (EP 3913 and EP 3915, both from the EPOXIDUR series) for the LDS process. After being cured thermoplastic components possess three-dimensional molecular networks, giving them a high heat distortion temperature and interesting mechanical characteristics. It will be exciting to see the results of the first LDS-MID projects to utilize this material.

A PDF on the high-performance LDS materials can be downloaded from the LPKF website. More information on materials can be found at http://www.raschig.de/Plastics-Division.