Fab Academy 2014,
Masato Takemura

Weekly Assingments

Class9: Molding and Casting
March 26th,2014

Memo

This week I lerned the method how to reproduce by making mold.

Assignment

This week's assignment is making mold and cast.
I lost a emblem of my car. So I tried to make it.

1.modeling

First, I have to measure the size of emblem and make data from the size. So I took a picture with a measure. then I import the picture to Illustrator as a template and resize its to 1:1 scale. I prepared a 10mm square for fitting.

fig.1

I wrote a picture of new emblem on the picture.

fig.2

After I edited the draft, I import the .ai to Rihnoceros. And I push up the closed path. Then I disigned a mold.

fig.3 3D Model

2.making mold

I used a software "CUT3D".It's a software from Vectoric. It can generate Gcode from STL model. I made a "rogh-cut tool Path" and "finishing-cut tool Path".

cutting parameter
	tool	stepover	pass depth	time
Rough cut	6mm endmill	3mm	4mm	2H
Finishing cut	3mm endmill	0.3mm	-	1.5H

fig.4 GUI of CUT3D

I used a Homebrew CNC milling machine. I open G-code on CNC interface software and started cutting. After Rough cutting, I changed endmill 6mm to 3mm and started Finishing-cut process.

fig.5 Cutting along the Rough-cut tool path

fig.6 milled mold, melting a bit

2.pour silicon

I used some silicone material I could buy in Japan. Product name is "Blue Mix".

shore durometer	Type-A 15-19
time for harden	30min
working time	4min
mixing rate	mix requiedA and B as 1:1
cost	$20/100g

fig.7

After I mixed the 2 requids, A and B. The time till harden is about 4min on datesheet. So I quickly stir and pour to mold. Tip of puring is ... pour silicon like a string from high position. It will not take bubble in. I set pole for making hole that pour casting material.