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10. Molding and casting


group assignment:

  • review the safety data sheets for each of your molding and casting materials,
  • then make and compare test casts with each of them
  • extra credit: try other molding and casting processes

individual assignment:

  • design a mold around the stock and tooling that you’ll be using,
    • mill it (rough cut + three-axis finish cut),
    • and use it to cast parts
  • extra credit: use more then two mold parts

What I did in this week

  • Review the safety data sheets for molding and casting →Group Assignment
  • test casts →Group Assignment
  • Design data in Fusion 360 →in this page
  • Molding and Casting →in this page

Design data in Fusion360

What I want to make by molding and casting

I wanted to make the totem from the movie Inception which is one of my most favorite movies in the world.



The workflow on this week is as follows: you mill out your design from the block of wax, then you pour a rubber substance into the wax to make a mold, then finally you pour a third substance into your rubber mold to make your object.

Design Process in Fusion 360

  • design posi which is final parts


  • Create nega parts which can be fit to the final parts. After that, create pouring spout and air ventilation for pouring the material. Nesting for assembling 2 parts is created.


  • It was careful for the endmill not to intervene the object in a milling process. Actually, it is careated frustum of a square pyramid instead of rectangular in order not to intervene the endmill.


  • create the block of WAX which can be fit to the nega parts


  • design process is here


fusion data is here

  • final model

  • take measure of Machinable wax

    • catalog size: 152mm x 92mm x 39mm
    • real size is smaller
  • save the body of WAX as mesh to .stl

Milling TIme!

Rough cut

  • open the mods to select the file of the WAX .nc data


  • 2.5D setting is here

  • edit the path to G-code
  • set the cut speed
  • culculate → nc file downloaded
  • check the preview site by loading the above .nc file.


move on to the step of Gsender

  • Determine the cut parameters, checking the milling time
    • tool diamater 3.175 mm
    • cut depth 3mm
    • max depth 37mm
    • cut speed 15 mm/s
    • plunge speed 1mm/s
    • jog height 2mm
    • spindle speed 6500 RPM
  • set and calibrate the position of xyz
  • load the data to Genmitsu
  • set the WAX on the milling position


  • finish to mill in 40min

  • done

    rough cut.jpeg

Finish cutへ

  • setting the mods


  • Determine the cut parameters, checking the milling time

    • tool diamater 1.5875 mm
    • stepover 0.2
    • direction yz only
    • cut speed 20 mm/s
    • plunge speed 4.65mm/s
    • jog height 2mm
    • spindle speed 10000 RPM
  • Load the finish cut .nc data to Gsender
  • Milling and finish to mill in 45min-1h


  • done

finish cut.jpeg

Casting Silicone mold

  • measure the volume of silicon in fusion360
    • bigger nega parts:58.99 ml
    • smaller nega parts:43.45 ml
    • specific gravity 1.08 g/cc
    • estimated total weight of substances is 112g
  • the substance is below. safety check is written in group assignment page


  • Measure 60g each of A and B. Wear gloves and protective glasses. Ensure good ventilation. Be careful not to touch here and there with hands that have been touched.


  • Since pot life is 5 min, mix and pour within 5 min. After mixing, pour the mixture into the WAX from the top.


  • I waited for more than 45 minutes because the cure time is 23 degrees and 25 minutes, and today it is 18 degrees.

    waiting silicone.jpg

  • fixed


  • When silicone is ready, sandwich it between and MDF and apply rubber bands.


Casiting Trial1: Smooth Cast 320

  • the pouring substance is Urethane resin: Smooth-Cast™ 320
    • Weight 100A:90B
  • Mix A and B, colored with green So Strong

    mixing 1.jpg

    so strong.jpg

  • I tried to pour quickly, but the pipe was too thin and would not go in.

  • As a result, only about a quarter of the planned amount went in.


Casting Trial 2 : Retry the Smooth Cast 320

  • To solve the slow pouring problem, we now operate on the pipe with a cutter to spread it out.


  • Mix quickly and pour quickly.

  • Mix A and B. Put in yellow So Strong and color it.
  • This time I was able to get all the liquid in


  • done


CastingTrial 3 : Metal

  • the pouring substanve :
    • Bismuth Based Low melting point alloy bullion : Sn + Bi
    • melting point : 138 °C


  • heating the metal to be liquid and pouring


  • waiting to be cold


  • done


  • cut off the extra parts and sandering


  • finishing


  • spinning the totem to chech whether this world is in dream or not…


spining totem

What I learned in this week

group assignment and individual assignment

  • Complex three-dimensional objects can be created by making molds.
  • The same mold can be used to create shapes in a variety of materials
  • This week is very enjoyable to make something new :)




Mr.Tamiya and Ms.Kamei as supportive instructors in Fablab Kannai


and You!

Last update: July 9, 2022