Week 3. Computer-Controlled Cutting

Group Assignment

Our first group assignment was started by Areg. First, we began with a small maintenance task for the laser cutter. We changed the fume extractor filter and cleaned the laser lenses and mirrors.

Then we designed a test file to understand the optimal speed and power settings.

This test is very important because, at different speeds and power levels, the kerf is different.



After cutting, we started measuring the cubes and tried to find the best one with the smallest kerf.



Then we measured contour of cube on the plywood.



Kerf = difference between the sizes before and after cutting divided by 2.

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This means that the laser removes 0.15 mm of material from each side of the cut.

Laser Cutting

About our Laser Cutter

Since I have been working in the Fab Lab as a technical support engineer for one and a half years, I know our laser cutter very well. Let me describe our laser cutting machine!

It is a Chinese CO2 machine, Kimian 6040 with a RuiDa controller.



Here are the specifications of our laser cutting machine:

Feature	Specification
Country	China
Model	Kimian 6040
Controller	RDC6445GZ
Laser Type	CO₂
Laser Power	80W
Work Area	600mm x 400mm
Max Cutting Depth	8mm-9mm
Supported Materials	Wood, Acrylic, Leather, etc.
Max Speed	500mm/s
Cooling System	Water
Software Compatibility	RDWorks, Lightburn
File Formats	SVG, DXF, AI, PDF, etc.
Connectivity	USB, Ethernet
Power Supply	220V

Small Upgrade on Laser

As you can see, this laser intended for industrial work, not for education, so it has few integrated safety features. When we bought the machine, I immediately installed an end switch on the laser door so that if anyone opens the door during operation, the laser beam would be turned off immediately.
Here is how I integrated end switch in machine:



After I connect wires to laser beam switch.
Now when someone will open the door while laser working, the laser beam will turn off.

Designing Prop with Joints of Submarine (Parametric)

I started designing joints in Autodesk Fusion 360 , and I used parameters for sketch.<br></br>

Here, I used a circular pattern for the blades, and the quantity is also parametric.



Then, after finishing the first sketch, I extruded it by pressing the hotkey “E”.



There is a very useful feature called “Project”, and I used it here. I want to share with you that in Fusion 360, you can create a sketch on any face. I made a sketch in the middle of the joint to draw the blade for the prop, and by pressing the hotkey “P”, I got a projection of my needed face with all constraints.



Here, I drew the sketch of the blade.



The circular pattern of the blades (both in the sketch and as a body using the circular pattern feature).



And here comes the most interesting part of parametric design! In the video, you can see that when I’m changing the parameters, the sketch parameters update, and all the parts adjust accordingly.

Angled version

Since I love working hard and thinking deeply, I decided to try making the blades at an angle.<br></br>

Cutting Body using another body and keeping tools.



This model is also parametric, I’m using circular pattern and in “Quantity” section I wrote my parameter.

Designing Fixture for Laser Cutter

As you already understood, I decided to try making a fixture for the laser cutter to cut joints at an angle. I started by creating a sketch on my model where the joints should be angled.<br></br>

The fixture will also be adjusted using the joints.



After drawing the sketches, I made an extrude to see my fixture in 3D.



Back view of Extruding.



So, I will engrave a small line to set the correct direction after cutting one joint, and I will place a shaft at the center.

Cutting Part

The interesting part is just beginning! I took sketches from my model and imported them into the laser software.

After setting laser, speed to 30mm/s , power 50%, I started cutting.

Assembling was super easy, and after that, I inserted a 6mm shaft into the hole.

After assembling the fixture, I got the drawings from the prop and imported them into the laser software.

I drew lines specifically to get the right position with the fixture and to ensure the correct pattern.

Here is how it looks.

Okay, now Most Interesting Part!!!

I placed the part on the fixture, then lowered the laser bed and set up the laser focus.

Here is a video of the cutting process.

Look At this angle !! 😊

And here I realized that the blade angle should also be adjusted. I imported the blade into the fixture project and cut it to get the contour on the sketch.

Then I removed the fixture lid, placed it on the laser table, set up the direction, and made the raster for cutting blade on the same direction.

Here’s what I got in the end.

Then I assembled everything back, cut the blades, and set up the laser for cutting the joints.

The blades are assembling very well.

After cutting the joints, I started assembling the prop.

And Here is the final Photo of Propeller !!!

Vinyl Cutting

About our Vinyl Cutter

The vinyl cutter is a very interesting and useful machine. I have worked with it several times. Our machine is the Roland GX-24, and here are its specifications.

Feature	Specification
Cutting Width	Max. 584 mm
Material Width	50 - 700 mm
Maximum Cutting Speed	500 mm/s
Cutting Force	30 - 250 gf
Repetition Accuracy	±0.1 mm or less
Interface	USB, Serial (RS-232C)
Power Supply	100-240V AC, 50/60Hz
Dimensions (W × D × H)	860 × 319 × 235 mm

Here are the components of a vinyl cutter and how it is built.

Testing, Setting knife force

When I turned on the machine, it performed a home position setup, and the display immediately showed the function to choose the type of sheet. There are three options: piece, edge, and roll.

Since I am going to do a test, I decided to use a small piece. To do this, I need to place the piece between the clamping rollers and the main shaft, then clamp the rollers to the piece and select “Piece” in the sheet selection menu.

Very important information!! : you can place the clamping rollers only on the knurled parts of the main shaft to ensure a sufficient grip on the vinyl.

So, after selecting “Piece,” the machine automatically starts measuring the piece’s dimensions and finally displays them on the screen.

Time to set the force for the knife. To do this, press the “Force” button, choose the force, and hold the “Test” button.

After doing the test, the machine should make a circle around the square. If the force is set correctly, the circle should stay on the vinyl after removing the square. In my case, the force was not enough.

I started doing tests, gradually changing the force, and I got 130gf for this vinyl.

Submarine Logo

After getting the best force, I decided to make my Submarine logo to stick it on my laptop. I imported the file into Inkscape. Here is how to get vinyl’s dimensions from machine.

After getting sizes I wrote it in document properties.

After cutting the vinyl, I applied it to my laptop using tape.

Heat transfer vinyl on shirt

I also tried applying vinyl on a shirt.

For this I made again test for vinyl for shirts

Then I cut our lovely speech.

Here is my first fail. The reason is that after ironing, I didn’t let the vinyl cool down and started removing the film right away.

Then I tried again, let it cool down until it was completely cold, and it worked!!!

I also applied the logo of my submarine.

Here is the final Result!! 😊

Conclusion

Even though I have experience with CNC machines, this week was not easy—but it was very interesting! At the moment, I can’t say exactly for what angled joints can be used, but for mass production, for example, or if you need to make something in very large quantities, it would be a good solution to avoid using, for instance, a 3D printer. I really enjoy using machines in new ways. Also, parametric design is top-notch!

Files of this Week

• Fixture (Fusion 360)
• Prop Parametric (Fusion 360)
• Prop Angled (Fusion 360)
• Laser Cutting SVG Files
• Vinyl Cutting SVG Files

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Last update: February 19, 2025