Q: I need a fastener that is very low weight and offers good wear resistance for a robotics application. I need about 40 ksi in strength.

A: For your application I would actually suggest an engineered polymer fasteners since your strength requirement isn’t high enough to necessitate a metal . PEEK Extreme screws are made of a carbon fiber reinforced PEEK polymer. These screws provide one the highest tensile strengths of any polymer, with an ultimate tensile greater than 47 ksi. In addition, PEEK screws are very lightweight, far lighter than any metal fastener and will provide excellent wear resistance.

Q: Need to replace a standard steel washer with a non-conductive material.

A:   After speaking with this customer, I learned that he needed to replace a standard steel washer with a non-conductive material for a critical bolted joint. These washers needed to withstand 70°C temperatures while maintaining preload. He had been experiencing creep with non-metal washers  at elevated temperatures and needed to minimize this issue.

While Vespel (polyimide) fasteners may have superb creep properties, it may be overkill for your application.  Vespel is also very expensive. I think you may be better off considering PEEK fasteners.  It is much more affordable that Vespel fasteners and could hold up to the 70C temperatures easily. It is also very well known for excellent creep resistance (as well as chemical resistance and temperature resistance). To further improve the creep resistance, glass and carbon fibers can be added.  Glass fiber and carbon fiber will improve stiffness and creep resistance.

Q: Can you provide alternative for a nylon pan head screw?

A:   Here the customer needed an alternative to nylon. Resistance to electrical fields was a primary concern. In addition, he also needed a material that had a better dissipation factor than nylon. In this situation we would recommend PEEK. It has similar properties with regards to its electromagnetic properties, better dissipation.