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3. Computer controlled cutting

Group assignment: testing kerf & speed/power settings

We already use this laser cutter for around 5 years now. We also have a book with the speed/power settings for lots of the materials used here in the lab.

1. Using the laser: workflow in 2 parts

1. Lightburn software

For controlling our laser and sending files to it we use Lightburn software. This software has basic drawing abilities, so you could make a small design directly in here. It also allows you to import DXF, PDF, AI,… files. In it you can give power/speed settings to different colors.

setting parameters in Lightburn

In the cuts/layers panel you can select a color and select a mode for it. On the bottom of the screen you can select the library panel to choose from the already available materials and assign those settings to the selected layer.
You can also set the power and speed for this color in the layer panel manually, if it is not yet in the library. If you double-click on the colored layer, you get a popup window with more extra parameters and settings you can adjust.

Once all settings are correct you can choose how to send the file to the laser machine. In the laser panel you can choose a job origin and what parts you want to send to the laser.

setting parameters in Lightburn

2. On the machine control panel

After you switch on the machine it will go through a startup and homing sequence. On the control panel you can move and manage the laser.

laser control panel

  • first you have to move the laser bed back up with the Z+ button
  • You can put your material on the bed
  • Move the laserhead around with X and Y buttons until it is in the corner you want to start. Use the origin button to set the starting point.
  • Use the file button to select the file you want from the filelist. Confirm with enter.
  • You can now use the frame button to move along the contour of your design and check if it fits your material.

Next you need to focus the laser. In our machine the laserhead needs to be 6mm above the material surface. We use a 6mm piece of wood to adjust the height. Using the 2 screws you can loosen the nozzle and move it up/down. Place the focus piece on the material under the nozzle. And let the nozzle rest on the focus piece. Now tighten the screws again.

laser focus

Almost ready to do some cutting. Close the lid of the machine and turn on the exhaust-system.

Now on the control panel press the start/pause button


2. Test parts

For this exercise we wanted to do the tests again on 2 materials we want to use to make the press-fit pieces in.

  • First we made a drawing of some circles and rectangles to test different power and speed settings. For most new materials I guess the power/speed combo and make 5 to 10 different combinations or variations around it. All have a different color and each circle in the drawing gets a different color. That way you cut all circles and can check to see which cut was the best or cleanest

setting parameters in Lightburn

  • For the kerf tests we made a simple parametric part in Fusion360, to be able to test different kerf compensation and materials easily.

design file: pressfit tester in Fusion360 format

design file: pressfit tester in STEP format

  • hardboard 2.75mm thickness, is a very nice waste material from packaging sheets of PETG. So we want to use it by way op upcycling it.

laser speed/power test

kerf measuring

  • Speed/power test : 35/55

  • kerf tests : 0.1 mm

design file: hardboard test file in DXF format

  • kraftplex 1.5mm

kraftplex results

  • speed/power : 50/65

  • kerf : 0.1 - 0.15 mm

design file: kraftplex test file in DXF format

  • different material tests with press fit tester piece

pressfit tester used with various materials

  • (also test on waterjet??) update 22/03/2021 The waterjet has a broken axis, so I first need time to repair it. Then I will try some tests.

Vinyl cutting

It was already a real long time ago that I made a t-shirt myself, so this assignment was the ideal excuse to make one! I made the design for the t-shirt in Coreldraw, I got icon from an online library and put some text around it. To be able to import it into the Roland Cutstudio software it had to be exported as AI format.

design made in Coreldraw

design file: vinyl design file in AI format

One important thing to always remember if you do vinylcutting designs to transfer to textile is to mirror your drawing before cutting it!

Mirror the drawing before cutting!!

Getting ready to cut now. I inserted a roll of flexcut material into the vinylcutter, set the origin. And had to do a test of the pressure and speed settings first.

roland gx24

The Roland GS-24 has a test button on the machine which cuts a little circle with a square and a cross in it. The goal is to let it cut this and then see if you can easily weed out a part of this test. If that works ok, you’re good to go.

do a test to ensure correct settings on the machine

After the cutting is done it is time for the fun part 😉 . Time to weed out all the excess material you don’t need for the design. You can do it by gently pulling away not used material, maybe use a scalpel or pincers to help you along the way.

weeding fun!

With the weeding done, the vinyl cutting part is ready. Now to get it onto a t-shirt we use a heat press. You have to heat up the press to the desired temperature. In our case 180°C. Position your design on the t-shirt with the backing facing up an place both in on the bottom part of the heat press. Then press down and wait for 15 seconds.

ready to press some heat

After opening the press up you can remove the shirt, wait a moment and then peel of the backing sheet.

Parametric press-fit construction kit

For this assignment I wanted to try and make a construction part with an as simple as possible design. I did wanted all dimensions in the design based on 1 parameter. The thickness of the material. Actually I needed 2. I also had to use the kerf, to be able to make everything press-fit. I had to base all dimensions in the sketch on these parameters.

At first I did some tests in Coreldraw and used objects to try and make the design parametric. But it didn’t really work as fluid as I hoped. So I abandoned this route and went to use Fusion360.

I tried to design a part that had lots of different ways to interconnect with other parts. I also wanted to try and use a living hinge in it, so the combinations got more interesting.

First design attempts were not so good, I also had a lot of trouble getting all constraints in place to be able to mirror parts of the design and keep a symmetry while working.

It took me a couple of trials to get to a working design. So I thought. I tested version 1 by laser cutting some parts and trying to build with them. Resulting in the living hinges breaking.

So I had to iterate the living hinge part a couple of times and test it to get it right. It also seemed that the hardboard is not very “living hinge friendly”, it breaks easily. I also decided to make 2 different parts, 1 with hinges and 1 without.

And finally I got one of my sons to test it and build some things with it :-).

design file: construction kit file in Fusion360 format

design file: construction kit file in DXF format

Last update: June 8, 2021