Need two materials
Need two materials
(OP)
I was asked a material question today and I remember that you guys are the materials experts! The part will be rubbing on another plastic part made of PEEK, so we'd like the material to be soft compared to PEEK where the PEEK will wear the material it's rubbing against. We're looking to have a disposable and a reusable part made. The requirements of each part are listed below...
Disposable:
Lowest possible heat deflection
Great insulator
Soft material
Lubricous
Iso 10093 biocompatible
Reusable:
Autoclavable
Great insulator
Soft material
Iso 10093 biocompatible
May be 2-shot for strength and softness
Thanks a ton!
Disposable:
Lowest possible heat deflection
Great insulator
Soft material
Lubricous
Iso 10093 biocompatible
Reusable:
Autoclavable
Great insulator
Soft material
Iso 10093 biocompatible
May be 2-shot for strength and softness
Thanks a ton!





RE: Need two materials
Disposable
Ultra high molecular weight polyethylene UHMWPE
Reusable
POM / Acetal
If Pat and Pud overrule me then listen to them instead. They have actual hands-on experience of such applications.
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: Need two materials
Thanks again!
RE: Need two materials
ISO 10093 is Fire Testing....
http://w
H
www.tynevalleyplastics.co.uk
RE: Need two materials
RE: Need two materials
Forgot: Are these parts injection moulded? I assume so as you want some soft stuff.
Also, whatever biocompatibility standard is required, there will be various classifications within it - usually for contact with body fluid times.
Cheers
H
www.tynevalleyplastics.co.uk
RE: Need two materials
For the biocompatibility, it will come into contact with bodily fluid, so it must be a medical grade.
Thanks, and please let me know if there are any other useful requirements I left out.
RE: Need two materials
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: Need two materials
Not sure of the autoclaving requirement - most plastics are sterilized by EtO or Gamma ray. 135°C might be a bit high for UHMWPE?
So: further reading for you -
h
UHMWPE moulding flavours (inc medical)
and for softies:
http
There may be others, but these two are my personal favourites as they have excellent technical support (well, in the UK anyway!)
Cheers
Harry
www.tynevalleyplastics.co.uk
RE: Need two materials
Any grades of PE are subject to softening and deforming under load at normal autoclave temperatures.
At a wild guess from what I think you want, low monomer content nylon 6 might be worth consideration. Nylons are or have been used for suture. Additives to increase hydrolysis resistance, thermal stability and heat deflection (up or down) generally ruin biocompatibility.
PET might also be worth a look although it has limited life when autoclaved as does acetal.
Noryl (modified PPO or PPE) might also be worth a look although I am not aware of its bio-compatibility. It is very good foe bearings in constant contact with hot water.
TPX might also serve your purposes depending on what flex mod and creep resistance you require and on whether or not you can get an alocation. Last I heard it was in very short supply with only one manufacturer in the world.
Regards
Pat
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RE: Need two materials
As far as the Acetal and PET having limited life when autoclaved, that won't work for the reusable part. If I was to have PPO or PPE mechanically grinding along a PEEK part, would the PEEK be able to survive more so than either of those two materials?
RE: Need two materials
If data is available, Sabic, or your PEEK supplier might have it. Others who may have data are DSM or RTP
Regards
Pat
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RE: Need two materials
Regards
Pat
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RE: Need two materials
RE: Need two materials
http://www.freepatentsonline.com/EP0923945.html
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: Need two materials
Would you guys happen to have another suggestion for the part to be autoclaved? (If we can get to 20 autoclaves with the material, we'd be happy)
RE: Need two materials
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: Need two materials
RE: Need two materials
Hardness has little to do with wear resistance when plastics are comcerned....
H
www.tynevalleyplastics.co.uk
RE: Need two materials
One major factor is the change in properties as temperatures rise due to friction. Another is the change of clearance due to change in temperature.
Skin layer characteristics also have a significant effect as does natural tendency to lubricious.
Regards
Pat
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