Teflon coating on stainless steel springs 1

[Pras]

Hi,

We need to coat the stainless steel springs with teflon (25-30 microns)in order to increase the corrosion resistance. The spring wire diamter is 0.55mm and its un-compressed length is 9.5mm. We tried a few times but failed to achieve the continuous teflon coating all round the spring wire. The suppliers say that the coating process is difficult since the item is too small.
Could any one guide us on this please.
Thanks

 

[MJCronin]

Pras,

Have you heard/considered XYLAN coatings ?

The company description:

"Xylan coatings are a family of products developed by the Whitford Company for use as: lubricant and wear resistant coating, as a seal, as a release or nonstick coating, in materials handling, and under conditions of corrosion. Xylan comes in the 1000 Series for tough industrial applications, and in the 8100 Series, which meets FDA food contact requirements. Multiple colors are available, whether to match their surroundings, or to provide color coding."

XYLAN has been used in chemical process plants in applications such as piping flange bolts and vessel manway bolting.

See:

http://www.aic-coatings.com/xylan.htm

http://www.whitfordww.com/

http://www.secoating.com/fcoatings.html

Good Luck !!!

MJC

 

[WKTaylor]

Pras...

I visualize this wire-spring to be polished CRES formed to shape [hot or cold], with shap-cut ends.

The polished wire will have the greatest fatigue durability, but is very difficult to coat. Also the sharp cut ends will make it virtually impossible apply an adherent across/around the ends [can't paint a sharp edge].

What is the material and what are the environmental factors??? Would a different alloy, uncoated, be a better choice?

Have You tried: trimming the wire to length: rounding the ends by elecro/acid polishing/deburing; applying the PTFE coating to the straight-wire; then forming the spring shape?

It might also be possible to pre-coat the wire-stock and cut/form/trim as You normally do NOW... just allow the [rounded-off] ends to remain "bare"??? NOTE: "hot/warm forming" could be required to help the coating "creep" into conformance with the wound shape! Regards, Wil Taylor

 

[Pras]

Thanks MJC and wktaylor ! Your inputs will be certainly helpful to me.
Pras