Lecture on Laser Cutting and 1st Cardboard Joint Test

Today, Cecilia gave us a very good lecture on working with the Fab Lab’s laser cutter. The machine was a LaserPro Spirit GE and didn't work with the Fab Modules. An Illustrator template was used to send all information to the machine. This laser cutter would be able to cut a lot of different materials (up to 10 mm thickness)—except metal or glass—and engrave pictures (up to 8-Bit grayscale). This machine was simple to use (similar to a printer) and opened a lot of new possibilities of creative and precise work. Most important: Switch on the breather while cutting or engraving! If it's off, there's danger of fire. The graphic’s line had to be set to 0.001 mm in order to cut. Thicker lines would be interpreted as raster information for engraving. Colors, used in the draft, could have individual settings for speed and power as well as for raster and vector dependences. Unfortunately, there wasn't a lot of time this week to experiment—just 2 hours per person and production (we were 9 people sharing one machine).

Some notes

Thickness of cutting lines
0.001 mm
Cutting
red lines, speed about 6 or 7 % (cardboard), power 100%
Engraving
black lines, speed about 100 % (less for deeper engraving), power 100% (paper less power)
Additional settings
position relative, manual focus, vector and raster on, cluster on, optimization on, size extended (96 cm × 46 cm)
Breather
always on while cutting or engraving

The machine’s laser worked with mirrors. The greater the distance, the lower its power. A cutting test should be done in an area furthermost.

Fortunately, there was some time left and I got the possibility to work with the machine. First, I engraved a graphic on my notebook. Then I made a test file regarding the 3 mm cardboard which we would use.

To get a tight joint, gaps had to be 2.6 mm wide which corresponded to an offset of 0.2 mm.

On my way home, I got the idea to create a picture frame press-fit construction kit as well as a pedestal press-fit construction kit. Different sizes and looks could be simply and individually created. No glue, nails or screws would be necessary to build these picture frames and pedestals. Only some glass for the frames would be an extra if there should be glass with the frames.

1st Attempt: Design of a Picture Frame Press-Fit Construction Kit

Based on 4 mm thick hard material* (e.g. wood), I designed a picture frame press-fit construction system for some standard formats. Aspect ratios 1:1, 3:2 and 4:3, frame depth 15 mm, glass would be 3 mm. I limited the size as glass could get very heavy.

My first attempt is rather a concept graph than a perfect parametric template. Somewhere I lost cloned elements. The sheet is 2 × (96 × 46 cm). Blue shows a frame’s back element. Green shows sections 2 mm deep and 3.5 mm wide. These lines should hold an art work, a back element or a glass. Red shows subtractive sections. I would copy all elements into the Illustrator template and edit the colors and outlines for laser speed and power. This sheet isn't a good template and should be revised.

Please donwload the Inkscape file here: Picture Frame Press-Fit Construction Kit

Cecilia told me that the laser cutter could have problems to cut wood thicker than 4 mm.

2nd Attempt: Design of a Pedestal Press-Fit Construction Kit

I skipped the concept of a picture frame press-fit construction kit and focused on a pedestal press-fit construction kit only. That would be enough work and two hours production time would possibly be too short to accurately produce both concepts. It took some time to learn Inkscape. My work flow so far:

Now, I could create a union of a red original subtractive element and a green chamfer element (Mac: ctrl +)—all clones would look the same. Unlinking clones, I could easily create a union of clones and then a difference of black and red subtractive elements at one go (Mac: ctrl -).

My second attempt—design of a pedestal press-fit construction kit—is almost a parametric template. The demonstration shows a system with 10 × 10 cm elements. Sizes could be easily customized and extended later e.g. 10 × 20 cm or 20 × 20 cm elements. Regarding my Inkscape template, there was just one thing I missed: Changing the thickness of red joints, the elements loose their centered position along the guides. But guides and ‘snap to’ options helped me to fix that quite quickly.

Original Inkscape design files

How to use

  1. Green (chamfers) to add to red
  2. Red to substract from black
  3. Set stroke to 0,001 mm, black
  4. Set filling to none
  5. Laser cut all sheets, play and build

Regarding offset and stroke, the final cut file should look similar to the sample shown above.

Simulation

Rhino 3D helped me to simulate possible combinations and to find missing elements.

Using Rhinoceros, I built a complex test object today. This was very helpful as I found several missing elements. The test object below uses several elements of the pedestal press-fit construction kit. The system is very flexible. One could play around and create different forms. On Tuesday, I would cut the series and test it. Probably I would extend the series with larger elements as mentioned above.

Please download Rhinoceros test and simulation files here.

Production of a Pedestal Press-Fit Construction Kit

Joint tests

I just had time for a cardboard joint test. I would need an offset of 0.3 mm to get a tight joint. Cutting, I set speed to 2,7 % and power to 100%.

Finally, there wasn't enough time to cut wood as well. But the system turned out well. I produced a number of sheets. Due to its hollow form, cardboard wasn't the ideal material for the system but good enough for a test. I would like to make it bigger out of 4 mm thick wood. This small version was great for playing and creating landscapes! I thought about extending the concept and creating a shelf system.

A Solid Wood Cube Based on a Pedestal Press-Fit Construction Kit

Today I found some time to cut my pedestal press-fit construction kit out of 4 mm thick wood. I resized my templates to 20 cm. First I tested the joints. I had to use an offset of 0.3 mm (4:4,6 mm) in order to get tight joints. Then I cut 6 pieces to build a simple cube setting speed to 0,7 % and power to 100%.

Finally, it worked very well. The wood cube is very stable.

Vinyl Cutting a Matisse Flower With a Roland GX-24

I traced a Matisse flower using Illustrator and set the graphic’s outline to 0,001 mm. I inserted a red roll of approx. 60 cm width, set the origin by pressing the appropriate machine button and tested cutting with force of 80 to 110 gf and speed of 1 cm/s. Force set to 110 gf worked well.

I successfully cut the flower. Sticking it, a ruler helped to avoid bubbles.