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9. 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

Individual assignment: - Design a mold around the stock and tooling that you’ll be using, mill it (rough cut + (at least) three-axis finish cut), and use it to cast parts

Have you answered these questions?

  • Linked to the group assignment page and reflected on your individual page what you have learned
  • Reviewed the safety data sheets for each of your molding and casting materials, then made and compared test casts with each of them
  • Documented how you designed your 3D mould and created your rough and finish toolpaths for machining, including machine settings
  • Shown how you made your mould and cast the parts
  • Described problems and how you fixed them
  • Included your design files and ‘hero shot’ of the mould and the final object

What I’ve done this week

Group assignment:

Individual assignment:

  • Modeling (CAD: Fusion360)
  • Create tool path (CAM: Modela Player 4) & Processing (Roland: SRM20)
  • Molding
  • Casting

Overview

I made a cap for the tact switch to be used in the Final project

The reason for the silicone process (⑤) in between is because modeling wax (④) is too hard and difficult to remove when finally taking out the tact switch cap!

Button Datasheet

Modeling (CAD: Fusion360)

First, create a button cap

Boxes the button cap and cut the caps from the box

(Modify => Combine => Target body: box, Tool bodies: button cap, Operation: Cut => OK )

Split body

(Modify => Split body => Body to Split: box => Splitting tool: Offset Plane => OK)

Fillet the corners, then open and place them next to each other.

Make a base of the wax to be used in this project.

(Ferris File-A-Wax Blue: 148 × 88 × 37.2)

make a sink hole and an air hole.

Combine the two.

Combine the two so that they are positioned on the surface of the base

Export in STL format

Create tool path (CAM: Modela Player 4) & Processing (Roland: SRM20)

File => Open…

Set => Model

Set Size and Orientation

Enter the size of the modeling wax to be used in this project (X:148 mm, Y:88 mm, Z:37.2 mm)

Set Origin

Set Material

Select Modeling Wax

Next, set up for processing

Click “New Process”

Choose the type of process

Choose “Roughing”

Select the cutting surface

Select “Top[+Z]”

Choose the tool(blade) to use for the cutting in this process.

Choose 3.18mm SE4FL EM

End mill used in this assignment

136596 1/8 SE 4FL EM

3/4 LOC 2 - 1/4 OAL S/C MICROGRAIN ALTIN

Set the cutting area and depth

Choose the type of path to create

Counter Lines: Up Cut

Cutting Start Position: Lower Left

Set the cutting parameters

parameter value
XY Speed 24 mm/sec
Z Speed 10 mm/sec
Spindle 7000 rpm
Cutting-in Amount 0.5 mm
Path interval 1.8 mm
Finish Margin 0.2 mm

Enter process name and click “Finish”

Tool path is opened automatically

Click “Preview”

Processing time is displayed in the lower right corner

Processing time is 0:57

Click “Cut” to export the file

First, fix 5.5 mm MDF with double-sided tape to avoid damaging the SRM20 base

Fix the molding wax over it.

Set and ready to go

Open the file in SRM20 control panel exported by Modela Player 4

Select “Cut”

“Add” then “Output”

During processing, when the machined wax is accumulated and the surface becomes invisible, pause the SRM20 to make the surface visible

and then resume processing.

After “Roughing” is completed, next, “Finishing”

Set up the “New process” in the same way as “Roughing”

Choose the type of process

Choose Finishing

Select the cutting surface

Select “Top[+Z]”

Choose the tool(blade) to use for the cutting in this process.

Choose 3.18mm SE4FL BN EM

End mill used in this assignment

137212 1/8 SE 4FL BN EM

3/4 LOC 2 - 1/4 OAL S/C MICROGRAIN ALTIN

Set the cuttong area and depth

Choose the type of path to create

Scan Lines: X+Y

Cutting Start Position: Lower Left

Set the cutting parameters

parameter value
XY Speed 24 mm/sec
Z Speed 24 mm/sec
Spindle 7000 rpm
Cutting-in Amount 0.2 mm
Path interval 0.2 mm
Finish Margin 0 mm

Enter process name and click “Finish”

Tool path is opened automatically

Click “Preview”

Processing time is displayed in the lower right corner

Processing time is 1:43

Finally, process the following

Molding

I used two materials (Part A and Part B) for casting.

I tried silicon to put into wax mold. and it would be the silicon mold

Mix the two together (50 g each, in a 1:1 ratio)

Pouring in

Electric Sander vibrations caused bubbles to rise to the surface

Use a toothpick to break the bubble.

~~~~~ 24 hours later ~~~~~~

The silicone has hardened and easily peeled off.

Done🔥

Stack the two and tape them together.

Casting

Mix the two together (20 g each, in a 1:1 ratio)

Pouring in

~~~~~ 24 hours later ~~~~~~

The resin had hardened and easily removed.

Cut off the protruding parts with nippers and smooth the surface with a sonic cutter.

Done👍

I was able to fit the tact switch

Looks good to me

What I learned

  • It was my first time in the field of molding and casting, so I learned a lot.

  • Before I started, I had the impression that it would be very difficult because of the many steps involved, but I was able to understand it.

  • Once a mold is created, it is a very convenient method that can be easily duplicated, so I would like to continue to study it.

Appendix

Last update: April 20, 2022