10. Molding and casting¶
- 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
- 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
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 rough.nc data to Genmitsu
set the WAX on the milling position
finish to mill in 40min
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
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.
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
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
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
- cut off the extra parts and sandering
spinning the totem to chech whether this world is in dream or not…
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