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  1. Robbyod

    Teflon contact material with highest Co-ef of friction (D&S)

    Yes it is PTFE, Any durable material will do or likewise a non chemically applied coating/layer (Mechanically secured) on a different base material would do Im trying to keep the solution as simple as possible. Manufacturing Engineer Clonmel, Ireland
  2. Robbyod

    Teflon contact material with highest Co-ef of friction (D&S)

    Hi all, Im looking for a material with a high (relative to teflon on steel) co efficient of friction on teflon. I have managed to find (google) 0.04 steel-teflon 0.44 brass-teflon 0.24 Aluminium-Teflon but i would like some more options and i am unsure of the accuracy of the above results...
  3. Robbyod

    Need sample working drawings for 3d madelling

    Hit the nail right on the head. That is perfect. TY very much
  4. Robbyod

    Need sample working drawings for 3d madelling

    Not absolutely of topic, useful for brushing up on details maybe. It is a good resource, just not for detailed models which i could practice on. I have started modelling/designing some new equipment at work anyway, should keep me occupied. Thanks
  5. Robbyod

    Need sample working drawings for 3d madelling

    Firstly, Not a student anymore (read above) Second, Im pretty sure that the small town library near me does not have 3D modelling in parametric CAD books lying around. My college library definitely does (but im no longer a student remember), but not the one where i live. The library has been...
  6. Robbyod

    Need sample working drawings for 3d madelling

    Ok, After a LOT of searching the best i can find is below. The first link has numerous drawings, the others are links to just one drawing. They are the only fully dimesnioned drawings i can find with google. I also thought i should start with some of the 3d model examples that come with...
  7. Robbyod

    Need sample working drawings for 3d madelling

    I have found two small drawings already with google image where the dim's are still legible, but im looking for more. I though there might have been an online resource that i didnt know about. The old books are a good idea, but short of finding one on eBay, i dont think i will get one I will...
  8. Robbyod

    Need sample working drawings for 3d madelling

    Hi all, Im trying to brush up on my parametric CAD skills, something i havent done much of since college, and im looking for samples of working drawings which i can attempt to make a 3d model of. Im using T-Flex (not willing to pay for Pro-E or Solid works) which has some good tutorials but...
  9. Robbyod

    Intersection of two normal distributions

    Sorry, the file attachment function doesnt seem to be working
  10. Robbyod

    Intersection of two normal distributions

    Thanks guys, what i did in the end was create an excel template which will calculate the % overlap of two data sets which can be pasted in. Much easier than running through differential equations. The template is giving me almost identical answers to the estimations i made with JMP (identical...
  11. Robbyod

    Intersection of two normal distributions

    While the underlying issue is a tolerance issue, the question and its specifics are statistical, which is why i chose this forum. So, does anyone have any ideas?
  12. Robbyod

    Intersection of two normal distributions

    Hi all, I am trying to find formulae for calculating the overlap between two normally distributed populations. There are some online calculators specifically for this but they do not have the resolutinion i require. So for M1,?1 and M2,?2, (where M is Mean and ? is StDev) what formula will...
  13. Robbyod

    Estimating die wear, Tungsten on Nylon

    @Mike I dont think pin gages are suitable, a set of pin gages with a resolution of 0.0001" and ranging from 0.025"-0.038" would be a very big set of pin gages (130). Already have sets with a resolution of 0.001" but thats not nearly good enough to detect tolerance issues with the dies...
  14. Robbyod

    Estimating die wear, Tungsten on Nylon

    Thanks for the info guys, Regarding material/process change resulting in chemical attack, i will follow that up, but i dont know whether this has happened just recently, or has been happening gradually for years. The nylon is part of a medical device, and as such is subject to FDA req's on...
  15. Robbyod

    Estimating die wear, Tungsten on Nylon

    Thats what i thought, and i assume thats what the original validation crew thought. Something went wrong somewhere however and the IDs have significantly increased. I am dealing with IDs of 0.025"-0.038", with spec windows of 0.001". The observed increases so far have been up to 0.0006", which...
  16. Robbyod

    Estimating die wear, Tungsten on Nylon

    Hi all, I have recently been presented with a problem posed by die wear. The dies are used for necking nylon tubing while on a mandrel at ~250°F. They are made of cemented tungsten carbide (unsure of exact composition/grade but may have data on this in the future) and seem to have worn quite...
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