Need help selecting a high temp plastic

[ChrisKoz]

I'm working on a new product and need some plastics assistance. I'm looking for a high temp plastic that can withstand having a carbon fiber shaft shoot across it at 350 feet per second or greater. Lots of heat for a few milliseconds, and lots of wear. Properties needed would be high temp resistance (500 F or greater), wear resistance, and of course moldable. So far, I've found RTP 4003 TFE 15. Delrin AF (at 185 F) didnt work, wore out.

Any Ideas?

Also, is there such thing as a wear resistant, high temp, SOFT material?

Thanks for any help.
Sincerely,
Chris

 

[btrueblood]

"Also, is there such thing as a wear resistant, high temp, SOFT material? "

In my experience, no, or at least no better than PTFE. Let me try to read between the lines, to help you make a better material choice: the carbon fiber shaft is the item you are producing or testing or whatever, and having these parts become damaged due to abrasion against the plastic pad would not be a good thing.

If the above is correct, then you WANT the plastic to wear before the shaft does, thus teflon (PTFE) in an unfilled (no glass fibers or mica) grade would be ideal. Make the pad a replaceable item, easy to remove, and stock spares.

 

[ChrisKoz]

The carbon fiber shaft is in fact, an arrow shaft. The plastic parts I'm designing will hold the arrow shaft in place while an archer shoots his bow. These arms will be in contact with the shaft for a few milliseconds before the arrow is launched. I'd really want to get thousands of shots off before the arms wear out. Replaceable arms are possible, but requires more parts, more design time, more cost. This is an economy arrow rest. Also, the customers are not really rocket scientists.

We have always chose between a hard and wear resistant material which can be pretty loud as you draw the arrow across the rest, or soft and very quiet with the downside of wearing out in very few shots.

I'd love to have a material that was wear resistant, and quiet; but I'll settle for wear resistant.

Thanks again,

Chris

 

[cpretty]

Have a try of PETP. This stuff is pretty hard, low friction, and good wear. It is commonly used in bearings and rollers that need to be quiet. It is used for bearings over other plastics (UHMPWE etc) due to it's high resistance to heat.

Being a engineering plastic it will be expensive to mould of course, but there is always a compromise with these type of problems.

 

[patprimmer]

PTFE is the material in my opinion. My second choice would be Nylon 4.6, third choice nylon 6.6 maybe MoS2 and graphite filled, fourth choice Polyester block co-polymer elastomer like Hytrel or Arnitel. The last one would not wear as well, but would be quiet. PTFE will be best.

Regards
Pat
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[ChrisKoz]

Thanks pat and cpretty for the tech help. I'll look into these.

 

[Pud]

PEEK has inherent low friction/high wear resistance.

It's also mouldable.

Harry

http://www.tynevalleyplastics.co.uk

 

[ChrisKoz]

Thanks Harry.

Im also looking hard at RTP PPA with 30% glass, PTF and silicone added.

 

[patprimmer]

I would not use glass filled as it will damage the shafts as the resin wears and exposes glass figres. If you feel it needs a fibre reinforcement for some reason I can't envisage, use carbon fibre.

Regards
Pat
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[Demon3]

As you realise, your demands are contradictory and impossible to find in a single material.

You want a hard material that takes high temperature with wear resistance but then you need it to be soft so that it damps sound.

I have some ideas.

Try a two material solution. For example a soft polymer (elastomer) for the bulk of the material so you get sound damping. Then a thin coating of a hard, wear resistant material on top. Perhaps aluminium foil.

Also, try a cheap, easy to mold material and then stick on a thing layer of low friction wear-resistant polymer. For example, you can buy PTFE tape and UHMWPE tape at

http://www.cshyde.com

When I want to find an optimal surface, I buy tapes from them and try them out. It's way cheaper and quicker than molding your part in several different materials.

Chris DeArmitt

"Knowledge has no value except that which can be gained from its application toward some worthwhile end."
Think and Grow Rich - Napoleon Hill

 

[patprimmer]

Most material suppliers will supply test plaques from which a test pad could be fashioned.

PTFE can be compression moulded by a PTFE specialist moulder. The material is relatively expensive and expensive to mould, but it is soft, ductile, extremely low friction and very highly temperature resistant.

Regards
Pat
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[davidmoul]

I don't really understand the need, cause such rest are existing in the archery industry. You can find some cheap one in plastic, and some more sofisticated with a moveable part.

What do you want to improve this way?

 

[dwightdixon]

No need to completely reinvent the wheel whenever you have a new idea or market opportunity. Look at the most closely competing products and do a material analysis. (It is cheap.) They most likely already done the work to find the "best" material for the application. Now make your design and function better and you are ready to market.