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14.Composites

This week's assignment

  • Design and make a 3D mold (~ft2), and produce a fiber composite part in it


This week I tried to make an Umblrella stand by using fiber conposites.

I have used below tools and materials to complete this assignment.

  • Software:
  • -Autocad fusion360
  • -Roland Vpanel
  • - Roland modela Player4

  • Hardware:
  • Roland SRM-20
  • Electoric Scale
  • Utility knife
  • Clamps
  • Vacuum cleaner

  • Materials:
  • Sillicone
  • Resin
  • Plastic Cup
  • Stir stick
  • News paper
  • wire
  • Disposal gloves
  • Dye for resin
  • Cotton fabric(white/red)
  • Dye for resin
  • Pure walnut oil(as release agent)
  • brush
  • pices of wood
  • Styrofoam
  • Compression bag

  • References:
  • - Composite demostration - Fab Academy Paris
  • - Class text

  • Procedures:
    1. 3D modelling
    2. Milling Styrofoam
    3. Test(vacuum)
    4. Test(Make Coupon)
    5. Make Sillicone mold
    6. Composites casting



    Procedures:

    1.3D modelling

    I wanted to make something useful, then I modelled octpus shaped umbrella stand by using fusion360.

    [make 3d data]

    This shape seems a little complecated, still not sure is that possible to make composite object.


    2.Milling Styrofoam

    As there is no suitable size material, I decided to use styrofoam and CNC milling by SRM-20.

    Before milling CNC, need to cut styrofoam. I used laser cutter and nichrome wire to make styrene cutter.

    Cutting styrofoam

    It took quite long time like 8hour for rough and another 7hous for finishing surface. I made negative and positive mold.

    Though it take to much hours, result was aceptable.


    3.Test(vacuum)

    Try to know wheather possbile to use vaccum bagging way this time.

    It seemed works but difficult to represent details, so I decide to use 2-side mold. Other than that, styrofoam is not strong enough, it was deformed when used vacuum bagging.

    4.Test(Make Coupon)

    I studied making coupon method by fablab Paris video and tried by our slf.

    I piled up 4 fabric layer and result was quite nice. Unless using food wrap, it sticke tightly. Thus using food wrap is compulsory.

    5.Make Sillicone mold

    As styrofoam was not strong ennough, I decide to make sillicone mold just same as week 11. But I had concern that surface of styrofoam is quite rough and don't know weather possible easily to peel off resin from sillicone. So I tested by using same materials.

    Result was same as expected. It's very tough to remove from sillicone, except using release agent. I tried to use walnut oil as release agent.

    [Sillicone stick to styrofoam mold]

    I paint walnut oil with brush, then pour sillicones into styrofoam mold.

    After 2days, I successfully release siliccones mold. But those are very oily. I washed them with soap.


    6.Composites casting

    It's time to execute this week's main event. As test shot I tried to follow week11(mold and casting)'s procesure. Just use resin instead of adding fabric yet.

    [pour resin into sillicone mold]

    Trouble occcured. Sillicones mold and resin stick very tightly and hard to remove. Finally it was broken.

    Possible reason was sillicon surface was not flat and smooth as week11's modelling wax. Also mold's wall thickness was not enough. Maybe it's better to use modelling wax or use release agent and add ejector pin.

    I want to try again! Use appropriate mold and cast material.

    Files


    Appendix

    [if successfull, composites process should be like this.]

    What We've learned

    • Milling mold by SRM-20 really need long time. I should learn better operation like direct CAM control by fusion360 and also follow standard operation procedure also use appropriate material as well.