Our series on LDS design guidelines ends with packaging and quality assurance in MID production. All of the MID design rules are made available in this newsletter as a download.
 
In principle, almost all of the standard packaging techniques can be used to assemble an injection-molded circuit carrier with surface mounted devices (SMD). Users can choose between lead-free soldering, gluing and wire bonding. The most suitable packaging method depends mainly on the component to be fixed and the area of application of the specific MDI subassembly. The area of application is also a key factor in the selection of the proper MID material – in particular, the thermal properties of a material are extremely important. 

Three-dimensional assembly saves a great deal of room but is also a very challenging process to master. Although SMDs can be easily positioned at different levels, the parameters of the automatic assembly process need to be taken into consideration during the planning stage. The main aspects are to ensure that nothing hinders the free movement of the solder-paste dispenser and the component vacuum tweezers. Placing SMDs on slopes should also be avoided, and there should also be a gap between the SMD and the edge of the component.

Process-optimized systems, and regular control and maintenance, are vital to guarantee the permanent high quality of MID production processes. Optical inspection for instance can be used to control the results.

If you have any particular questions on packaging, quality assurance or the design of mechatronic modules in general, please contact Dr. Wolfgang John (wolfgang.john@lpkf.com), senior consultant at LPKF on the LPKF-LDS® method. Dr. John has been one of the most highly respected experts in the MID sector for many years.