Wear Resistant Polymer 2

[nlj]

I have a component currently made of anodized 6060-T6 Aluminum. The component has two wear surfaces that extend in a twisting manner to unlock a latch. I'm told by the designers that aluminum was chosen in efforts to reduce weight and it was anodized to assist in wear resistance. I was orginally thinking the aluminum component could be lined with a lubricanting polymer, but then thought there would be issues with the different coefficients of expansion.

My next thought was to make the entire component could be made out of a polymer (say Nylon or Delrin) but then thought that there would be an issue with a nylon-on-nylon wear surface. Are there polymers that withstand wear between similar materials? Or would I be better off making the component out of steel? I would only be saving a few pounds at best making it out of a polymer.

Any advice would be appreciated.

 

[patprimmer]

Nylon on acetal (Delrin is but one brand name) has very good bearing qualities.

Additives to the nylon and/or acetal can greatly improve bearing and mechanical properties.

The aluminium can be coated with PTFE.

Hard anodising has much stronger surface than std anodising.

Regards
Pat
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[IRstuff]

We typical use steel inserts on wearing surfaces for aluminum housings.

TTFN

FAQ731-376

 

[Pud]

Best choice is Acetal on Polyester, if you need precision. Otherwise as Pat suggested, Acetal/nylon.

Some fillers in polymers (eg Aramid/ Carbon fibre) need careful consideration as they will wear metals in preference.

Btw, depending on volumes, you might find for injection moulded parts, the "in position cost" are way cheaper than machining stuff.

Materials with tensile strength approaching cast Al are readily available.

H

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

The additive packages that work with nylon and acetal are:-

Molybdenum disulphide in the nylon to act as a very effective nucleating agent and so introduce a very fine crystal structure.

Graphite powder in the nylon to lubricate the surface.

PTFE in the acetal to improve wear resistance by lubricating the surface after some wear occurs and it will reduce dynamic friction in the long term.

silicone oil in the acetal as it will migrate to the surface and reduce static friction.

Regards
Pat
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[unclesyd]

Here is some information on Nylon (Nylatron) as mentioned above with some data. The second link to Quadrant is a list of a some engineering plastic materials if Nylons won't do the job.
In our machinery Nylatron was the work horse of the Polymers. This was not only for its properties but the cost and being readily available.

http://www.quadrantepp.com/default.aspx?pageid=77

http://www.quadrantepp.com/default.aspx?pageid=47

 

[nlj]

Thank you all very much. I'll be curious to see if they opt to use a plastic or make it out of steel.

 

[GilPolymers]

Hi,
I'm not experient enough but maybe there is other material that you can take into considereration:

Vespel(R) from DuPont (it's a polyimide). Specialy filled with graphite, offers good mechanical and wear properties is a large range of temperatures.

Does anyone else has experience with this material? Comments?

Regards,
PG

 

[fredUK]

Quadrant plastics would be a good bet to find your ideal solution. They have excellent technical support and if you ring them up, explaining your application, they’ll offer a cost effective material to achieve what you require (btw – I don’t work for them but it sounds like it doesn’t it). I imagine that they’ll suggest a material such as Ertalyte (excellent wear resistance). I am currently using Ertalyte TX for a button in a bayonet type arrangement under high loading and vibration. If you look at the link, you may be able to find more info on what is available. Page 10 shows the Ertalyte information, including a graph of wear rates of different plastics. Note that there are many other considerations required in selecting the plastics, of which there are “endless” varieties, so the more information you have regarding your application, the better!

http://epp.quadrantplastics.com/assets/global/Europe/EPP/Literature/Prod_ApplGuideE.pdf

 

[fredUK]

Peek is another material, which is probably ideal for your application. However, this is not cheap, and if you did go for this, you will be looking at about 5 times the price of ertalyte.

 

[patprimmer]

Ertalyte is a trade name for one brand of polyester. Polyester has been mentioned earlier.

The linked catalog is quite useful thank you

Regards
Pat
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[nlj]

Thank you for the replies. The catalog has a lot of good info for future applications too!