Computer-Controlled Cutting
Group Assignment
For this group assignment we choosed to test the laser cutting machine Trotec Speedy 400 (1000mm x 610mm / 100W).
The jobs are run from a computer next to it, through Rhinoceros, print driver and controller. The software is basically used for importing files and assigning colors and layers. This step is important, especially if you are going to work with more than one work operation.
To set well the focus of the laser, we had to adjust Z-axis heigth:
For our tests we used Cardboard and Plywood and tested these settings:
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Cut:
4mm Cardboard: 50 Power, 1 Speed, 1000 PPI
4mm Plywood: 75 Power, 0,8 Speed, 1000 PPI
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Engrave:
4mm Cardboard: 30 Power, 100 Speed, 1000 PPI
4mm Plywood: 60 Power, 100 Speed, 1000 PPI
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Raster:
4mm Cardboard: 80 Power, 100 Speed, 1000 PPI 4mm Plywood: 60 Power, 100 Speed, 1000 PPI
The best results were 3.85mm and 3.35mm gaps for plywood and cardboard respectively. This big difference between the two comes from two reasons:
- The cardboard had a bigger kerf. Maybe just because the material burn more easily. But we believe it may come from laser being over powered
- Cardboard squeezes way more than plywood. Fitting in tighter gaps.
Finger Joint Test
After getting the right settings for the materials, we went to test the press kits.
Additionally, I tried out how to set parameters Fusion 360, to see it's effect on form and size of the fingers.
Conclusions
The best results were 3.85mm and 3.35mm gaps for plywood and cardboard respectively. This big difference between the two comes from two reasons:
Individual Assignment
Vinyl Cut
For this assignment I used the Vinyl Cutter Roland GX-24 Camm Servo 1 to create labels for the FabLab. In the first step I designed the text and symbols in Adobe Illustrator.
The design has to be vectorized, otherwise the Vinyl Cutter would not be able to cut the border lines. Also, text and drawings would not appear in the machines program Roland Cut Studio (software version 1.5.1).
In the next step exported the design in different formats, so I choosed these four formats: ".ai", ".dwg", ".png" and ".svg". The Adobe Illustrator document had to be exported it in an old format version (in my case Illustrator 3). The newer versions from AI CC are not readable.
There are two options to cut with the Roland Vynil cutter: one is to cut on a Vinyl roll, here the material feed has to be done from the backside. The other option is to feed the material from the frontside, for this I had to select the option "piece". In the second case the cutter might recognize the dimensions by its own, alternatively I could measure the piece by my own and introduce the dimension in the settings of the Cut Studio program.
Mounting the Vinyl
After the machine cutting I had to wrap off the adhesive foil. I used tweezers to seperate and remove the parts, which were not going to be used. This cut was almost good, there were only little parts uncut, as it shown here:
Actually there are two ways to stick on a Vinyl. One technique is what I did here: I used Crepe Paper to remove the adhesive layer and mount it to wall, and then taking off the Crepe Paper again.
The other technique to mount the Vinyl would be, to wrap off the complete adhesive foil and stick it to the wall, and then remove the unused part. Also for this technique it is recommended to use tweezers.
Due to my time management I had to finish the labels before the FabLab's closing time. So in the last step I mounted the Vinyl by estimation directly to the wall.
Laser Cut
In this assignment I used the Trotec Laser Machine Speedy 400. To profit from the machine tests we did in the group assignment, I used the same set up and material, Cardboard 4mm.
The idea was to make a Samurai Sword with Cardboard, applying a simple press fit structure.
This first draw shows also a sheath for the sword, that I wanted to make, if there will be some time left.
Searching in the internet for a free 3D design of a Samurai swort I found this example.
For cutting this object I only needed a 2D sketch with the outlines. I made this with the Fusion 360 tool 'projection'.
For the grip I designed two type of circles with different sizes, with rectangular holes in the middle. Into these holes will fit the end of the blade shape.
Now the design is ready to be run on the laser cutter.
The cardboard was not a little bit uneven, so I had to repeat the cut, because some parts were not cut well.
The final result was pretty to look at and my son was very happy about his own samurai sword.
Conclusions
Making a Vinyl Cut is not really complicated, but in case the drawing or text patterns have a lot of tinny and fine pieces, the application can require a lot of time and effort. Small pieces are difficult to get wraped off and maintain them in their original position. A good mounting result also depends on the surface quality, where it is going to be sticked on. Preferably the surfaces should be smooth and even.
The Cardboard's properties are favorables for press fit designs. Cutting the pieces of the Samurai Sword was effortless, they fited well and could be sticked together very easily. But testing it's functionality as a child's toy, revealed the weakness of the material and the construction. After a few stress tests the blade broke rigth next to the grip. Cardboard modules should be used for other purposes;-)
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