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Recent content by GilPolymers

  1. GilPolymers

    Issue about position of flow tab with respect to plastic flow and location of weld line

    Hi, Have you consideres to change the gate location? Probably just by offsetting the gate you will manage to move the weld line to a less critical area. I agree with the comments before, if the issue is not constant then probably has something to do with processing or resin variations. GP
  2. GilPolymers

    COC vs COP

    Thanks Chris, In fact I was a bit under stress because I could not find any data on-line nor in my books collection, but in the mean time I found some info. COC is the same as COP but co-polymerized with blocks of ethylene (as suspected). I also find some differences on transmittance and...
  3. GilPolymers

    COC vs COP

    hi, can someone explain me the difference between COP and COP from structure point of view and let em know if there is any difference on their processing compared to each other? Thanks Gil
  4. GilPolymers

    Injection molding Simulation

    Hi all, Is there anyone aware of a free mold filling software? I would like to have only a rough estimation for pressure drops and filling time. Shear rate profile, crystalization, warpage, welding lines... etc are not of my interest with this free software. Thanks...
  5. GilPolymers

    Stack system design

    Pat, thank you for your feedback. Why do you prefer option B? Thanks
  6. GilPolymers

    Stack system design

    Hello all, I'm working on a layout concept for a stack mold with one cavity on each side (2x1cav). From the mechanical stability of the mold on the machine and the mold itself, what solution would you prefer (pleases see attached picture)? My opinion: Solution A advantaged: Forces will be...
  7. GilPolymers

    Torque calculation

    Hi, At university I had a course where I learned to compute the pressure raise and pressure drop (on the dies) on one extruder along the screw. We were using transport equations to compute the flow in the screw. The equations were divided in three steps, one equation for solids transport, other...
  8. GilPolymers

    Max Shear rate and shear stress

    Hi all, I'm looking for literature that could help me to define limits on the shear that you can apply to a certain polymer family. In the books that I have (for example: Runner and Gating Design Handbook: Tools for Successful Injection Molding and Mold Engineering) I have a table and some...
  9. GilPolymers

    Young's modulus

    Hi there, Is difficult to understand this post. As far as I understand from here I agree with Demon. Which kind of material are you looking for? Independently of the type of the material (polymers, metals, ceramics), their behaviour can be defined according to 3 big groups: (1) pure elastic...
  10. GilPolymers

    Selecting suitable polymer for Outdoor Call point?

    Excellent post... I was wondering if you could upload this diagram, if would fit perfectly on my notes. Thanks Cheers, Gil
  11. GilPolymers

    HIPS / Styrene Butadiene Copolymers

    Hi all, Today during a chat w/ some friends at work we end up at the question, which is the difference between HIPS or Styrene Butadiene Copolymer? I would like to share this question with you people to know also what you think about it. As far as I know HIPS is made out PS blended or...
  12. GilPolymers

    polymer used for golf tees

    Hello, Should they remain intact after the shoot? Maybe ABS or PC/ABS but I guess that those are too much for the application. I would say that a HDPE would work just fine. It should be stiff enough to be pushed into the ground and shound have enough impact resistance. I remember that when I...
  13. GilPolymers

    Rheology Classes

    Hello all, After my studies in Polymer Science and Engineering I decided to study by my own Polymer Rheology as I think that it's a powerful tool to understand a couple of flow behaviors in processing. I would like to share with you what I found. For those who are interested, you can download...
  14. GilPolymers

    Wear Resistant Polymer

    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...
  15. GilPolymers

    Help with finding correct composite for musical instrument

    Hello I know that some guys in UK made an "acoustic" violin with carbon fibres and epoxy resin. If I remember they used an autoclave system to manufacture the different components. Maybe you should look for something like that. I try to find the web page but I can't find the same web page that...
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