Kieback & Peter, a Berlin-based supplier of heating, ventilation, and air conditioning (HVAC) equipment, has turned to Ticona Engineering Polymers (Kelsterbach, Germany) to source Celanex XFR polybutylene terephthalate (PBT) grades for the housing of its new miniature actuator. The PBT material is rated UL 94 V-0 flame-retardant without the use of halogens or antimony.

“Current environmental and recycling regulations form an integral part of comprehensive technical specifications when selecting materials for complex components today,” says Heinz-Günter Onken, application engineer at resin distributor K.D. Feddersen (Hamburg, Germany). Onken recommended a Celanex XFR PBT grade with 20% glass-fiber reinforcement for the power-operated assembly used to actuate a fitting/valve.

In addition to flame retardancy, Celanex XFR PBT also provided good mechanical properties in snapfit hooks, tear and overtightening strength in screw domes, superior electrical properties, colorability in the company’s standard light grey, and compliance with Restriction of Hazardous Substances (RoHS) and Waste Electrical & Electronic Equipment (WEEE) directives.

As part of the product development process, Kieback & Peter and Feddersen worked together to develop mathematical models of effective forces such as screw and pullout torque, and recommended ways to optimize the manufacturing process. “Following the optimization process and subsequent testing, we were able to approve all three force transmitting components—base plate, housing, and flange—for production with the materials recommended by the distributor,” says Karsten Krause, Kieback & Peter’s head of mechanical development. —[email protected]