Motion system components are always susceptible to harsh conditions, especially those with a rolling action like ballscrews. There are plenty of protective additions for other components such as rail covers and protective casings, but the nature of ballscrews makes them particularly vulnerable.
Keeping ballscrews safe from extreme temperature changes and contamination is more difficult than with other components, but not impossible. Taking the appropriate measures can absolutely help prevent failure and extend the life of a ballscrew assembly.
Materials Used in Ballscrews Manufacture
The materials used in the ballscrews manufacture process can determine how resistant to contamination they are. The material used is especially important if the ballscrew assembly will be exposed to liquid contamination such as water, oils and acids, and even the likes of alkaline cleaning solutions.
Parts of the ballscrew to pay special attention to here are the screw shaft and ball nut housing. They are sometimes made with stainless steel which helps protect them from water and certain chemicals, but they are usually made with non-stainless steel so they can handle heavier loads and maintain a reliable rigidity. In the latter case, other materials can aid with the protection from contamination.
For example, some screw shafts and ball nuts will benefit from a additional protective coating. This can be in the form of black oxide, thin dense chrome or electroless nickel plating which can be applied to either the screw shaft, the ball nut housing or both.
Which option is better for which application can depend. Obviously the stainless steel is more naturally protected from contaminants but this is in exchange for a reduced load capacity. The downside of a protective coating is the potential for the coating to flake or separate under extreme loads. The coating will also add a few microns of thickness to the surface which could have an effect on the ball nut preload.
Ballscrew Seal Variations
Seals are a potential solution to protect ballscrews from contamination and serve the additional purpose of keeping lubricant in the raceway. Companies specialising in ballscrew manufacture usually provide a range of seal designs including full contact seals and brush seals.
Full contact seals match the size of the ballscrew raceway to prevent all liquid or solid contaminations from entering. Brush seals are designed to prevent solid contaminants.
The ballscrew manufacture process also offers the opportunity to build seals out of a variety of materials. The most common is FKM, a synthetic rubber and fluoropolymer elastomer. Another popular option is EPDM (ethylene propylene diene monomer), which is another synthetic rubber that is particularly efficient against certain chemicals as well as being able to withstand high temperatures.
If you require any ballscrews or other products made by ballscrews manufacturers, then contact YB Components who are the UK’s leading ballscrews suppliers who keep local stocks ready to ship out fast and free all over the UK and the rest of the world.