Laser Cut Mold Simple Project




Introduction: Laser Cut Mold Simple Project

About: Design and Make Studio | Furniture. Lighting. Accessories. Interiors

This project is an intro to the concept of laser cut mold making. It will allow you to do a small test project before tackling the Intermediate Laser Cut Mold Project.

Skills gained and reasons for doing the Simple Project first:

1 - Test the etch settings on your particular lasercutter with PETG and folding joints
2 - Experience with taping a simple leak free joint 
3 - Experience with entire process and concepts utilized with laser cut molds

Tools Needed: 

1 - Laser Cutter
2 - 2x Mixing Buckets
3 - Paint Stir Stick
4 - Kitchen Scale (weighing out casting material and water)
5 - Funnel
6 - Exacto or Utility Knife

Materials Needed:

1 - Plaster of Paris or your preferred gypsum based casting material (We use Ultra-Cal) 
2 - .030 or .040 PETG Sheet  Approx. 10" x 10" (This gives about 1" margin on all sides)
3 - 6mm or .25" MDF Approx.. 10" x 10" (This gives about 1" margin on all sides)  
4 - Duck Tape 

Step 1: Laser Cutting Support Structure and PETG Mold

Download the SVG files for the sample cube mold and the sample cube support structure. 
You will want to right click and select  "save link as".

Sample Cube Mold

Sample Support Structure 

Step 2: Assemble Support Structure

I found with this test piece that only the top support structure was needed (as seen in both photos)

Step 3: Fold and Assemble PETG Mold

By hand - fold PETG into shape and Duck Tape seams. Order of seam taping does not matter, but try to be neat about it as too much build up will cause it to not fit into the support structure and possibly leak. 

Step 4: Mix Plaster and Pour Into Mold

You will now weigh out the plaster powder mix and water (consult the bag/ or manufacturer for exact mix ratio) - I use two buckets and mix the powder into the water slowly while stirring.  For a small piece such as this a paint stir stick works well to mix plaster. 

The set up time will depend on the plaster product you use and the ratio of water to mix. We used Ultra Cal with it's recommended ratio - this gave us about a 40 minute working time before it set up. 

Step 5: Remove Part From Mold

Allow proper curing time - then remove part from mold. Part should literally fall out when you turn it upside down. 

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    7 Discussions


    7 years ago on Introduction

    Nice process! I can see real potential in these methods. I wish I had access to a laser cutter to experiment with it myself. Couple of questions: Do you draw the mold in 3D and have some software that unfolds it or do you do the development yourself? Does the laser cut and score the plastic for the mold or do you cut it some other way?


    Reply 7 years ago on Introduction

    Finster 101, I model the the cast piece, then offset the surface to create the "mold". Then manually create the unfolded version. It is a bit tedious. I would like to get in-touch with someone at Autodesk to work with them to develop a mixed program that uses their slicing and folding software to automate the process.

    The laser cuts out the perimeter as well as scores the internal fold lines.


    7 years ago on Introduction

    Very cool! I could see myself saving some decent moolah making my own custom retaining wall pavers.. Hmmmmm...


    Reply 7 years ago on Introduction

    Retaining wall pavers could be a great use - you could even cast or buy a silicon insert to give a texture on the one side of the block as well.


    7 years ago on Introduction

    Cool! Couple things:
    1. why PETG? Just the recyclable angle, or?
    2. I love that shape, but does it do anything? Or is this just for practice?
    3. Same with the support: why not just cut those simple pieces with saws? Or is it for practice?
    4. Lastly, link to the Intermediate Laser Cut Mold Project? Can't wait! :)


    Reply 7 years ago on Introduction

    Hi J.
    Glad you like the project.
    1. We had it on hand and originally we were interested in its potential to be a "living hinge" of sorts for etching and folding on more complex molds (did not work like I wanted, but duct tape does =).
    2. Just a super simple, highly drafted test part - we are currently developing a hanging pendent light with a similar shape over at pax modern.
    3. Any cutting method woud work, and really a lot of other materials would work for support structures - we have a laser cutter =) with a 2' x 4' bed and planned to make the larger and more complex pieces with the lasercutter. Laser cutting gets really handy with the advanced projects we are working on that play with compound curves and more complex support structures.
    4. Sorry I forgot to put the link in on the simple project. Thanks for pointing that out.