All the control elements of the kinematics of the injection moulding presses are located in aluminium housings whose dimensions are critical for manufacturing, but must be optically perfect. All the tool paths are not desirable on the exterior surface, and for this reason at the end of the manufacturing process, the parts are sanded with glass balls. The surfaces are then uniform and the result is optically unmistakable. Since many connectors are connected to these housings, each connector slot has a laser marked description.