Besides the contact components the plastic materials are the critical building blocks for electromechanical components. Plastics used are mostly technical thermoplastics and heavy-duty plastics which fulfill the requirements for high mechanical strength, temperature stability, and fatigue strength <xr id="tab:Frequently Used Plastic Materials and their Properties"/> <!--(Table 10.1)-->. For the final selection of a plastic material economical considerations and the avoidance of environmentally hazardous ingredients such as for example flame retardants must be considered. The application of the most suitable contact material coating and the selection of carrier materials are covered in chapters [[Contact Carrier Materials|Contact Carrier Materials]], [[Surface Coating Technologies| Surface Coating Technologies]] and [[Applications for Bonding Technologies|Applications for Bonding Technologies]].

<caption>'''<!--Table 10.1: -->Frequently Used Plastic Materials and their Properties'''</caption>

Hybrid frames and housings serve as the connecting points between mechanics and electronics <xr id="fig:Component with hybrid housing for use in automobiles"/> <!--(Fig. 10.1)-->. They allow the transmission of signals or electrical energy. The connection to the current paths inside the housing is mostly done by bonding with aluminum wires. The over-molded lead frames are typically manufactured from aluminum clad strip materials which are well suited for bonding. The connectors integrated into the housing for transferring the current paths to the outside are coated with tin, silver, or gold, depending on specific requirements.

In strip form over-molded contact parts reduce the complexity of assembly of the finished product. This complexity constantly increases with adding additional subcomponents <xr id="fig:Examples of strip over molded contact components"/> <!--(Fig. 10.2)-->.

For applications and materials which do not allow strip over-molding, semi or fully automated assembly processes can be utilized. Different single parts like printed circuit boards, stamped parts, or contact components are assembled together with plastic molded parts on specialized equipment to complete functional components with low tolerances and high levels of functionality <xr id="fig:Examples of assembled contact components"/> <!--(Fig. 10.3)-->. This also allows to integrate components which otherwise are difficult to mount onto circuit boards or carriers, such as capacitors, coils, or sensor elements into the functional component assembly. Contact parts used in these components are already tested on the assembly machine for quality parameters and functionality.