Week 3 - Computer Controlled Cutting: Elle, Amalia, Andrew, Jenna¶
Group Assignment¶
- Do your lab’s safety training
- Characterize your lasercutter’s focus, power, speed, rate, kerf, joint clearance and types
- Document your work to the group work page and reflect on your individual page what you learned.
Files¶
Plan¶
Project Plan¶
| Terms and Definitions | Jenna |
| Kerf Test | Elle, Andrew, Amalia |
| Speed Power Frequency Test | Elle, Andrew, Amalia |
| Focus Test | Elle, Andrew, Amalia |
| Joint Clearance Test | Amalia |
| Joint Types | Jenna |
Terms and Definitions¶
Focus - Focus, typically set at ¼, is the laser’s diameter. Focus length is the distance from the lens to the material being cut. The beam goes through mirrors, referred to as focus lenses, for precision.
Power - The laser beam delivers a certain amount of energy per second. The percentage means the percent of total energy capacity.
Speed - The speed at which the beam moves across the plane. Inversely proportional to the time that the material is being cut by the laser beam.
Rate - The rate at which the laser cuts the material, e.g. 9 m/min.
Kerf - Kerf is the width of the cut, directly proportional to other parameters.
Joint Clearance/Types - A gap between different parts of the product, created for them to properly be assembled.
Speed, Frequency, and Power Test¶
Designing the Test¶
When designing this test, we looked at how previous Fab Academy groups had made their test. We ended up creating our own unique design in CorelDraw that had a series of 30 lines with speed, frequency, and power at the top and percentages in increments of 10 on the right. We also chose to make each row of lines different colors, so over at the laser cutter, we could separate the design by color and alter the settings for each color. When creating this design, the most difficult part was evenly spacing the lines from each other. We ended up creating a vertical line that was the length of the desired distance apart and moving it to the end of each horizontal line, and where the other end was, we created the next horizontal line. Then, after finishing one column of lines, we copied and pasted the series of 10 horizontal lines twice.
This is the initial design we used for the test.
Our design on the carboard
Performing the Test¶
The first time we did the speed frequency power test, all the lines ended up looking the same. When we mentioned this to Mr. Dubick, he said it was because power and speed have an inverse relationship, so when power increases and speed decreases, the lines will turn out the same.
To fix this, we laser cut again but made the speed and power different. For example, we set speed to 10% and power to 100% and kept increasing speed and decreasing power in increments of 10%. After doing this, all the lines looked the same again.
We tried to change the settings so speed was 10% and power and frequency were 100% and kept power and frequency the same while increasing speed by 10% increments. This time, it worked, so we repeated this process for power as well. We incremented power by 10% and kept speed and frequency and 100%. After figuring out the settings we altered the design again in CorelDraw to better format the lines and percentages.
This was the design for testing speed, and we created a very similar one for power as well. Mr. Dubick mentioned that frequency does not really matter on cardboard, so we did not redo the frequency test.
Focus Test¶
Designing the Test¶
We chose to use a picture of Lightning McQueen for our focus test. We used the trace tool in CorelDraw to trace the image and then copied and pasted it five times. We also labeled the planned power numbers next to each image.
This is the design we used for the focus test.
Performing the Test¶
To test the difference in focusing, we used the Epilog Fusion Pro 48 laser cutter. Then we got a fresh piece of cardboard for the test. When adding the file into the laser cutting, we set the material to cardboard engraving and didn’t change any of the settings on the computer after that. We went ahead and sent the file to the actual printer. Then I went to the button on the laser cutter that has a line and two arrows pointing off of it. This tab is for moving the bed and this is what we changed to test the focus. The further away the bed was the less focus it was.
This is the Focus Menu where you edit the focus. This is where I clicked the move to button and edit the bed height.
This is what the editing looked like. To change it I simply typingin the number I wanted and clicked ok and the pressed play.
When switching the files, it was a very long process because each time I had to go into corelDraw and delete the old one and then add back the file. Then I would have to got to print and follow the same thing over and over.
Screenshot of the Lightning McQueens on the cardboard
The final image of the test. However, we labeled the numbers incorrectly, so the test labeled 0 is actually 0.5,and the test labeled 0.5 is actually 0.
Kerf Test¶
The kerf refers to the width of material that is removed during the cutting process after the laser beam vaporizes, or melts away a small portion of the material while running. While kerf may seem like a minor detail, it can affect the overall dimensions and fit of the final design, so it was crucial in getting it correct.
To test the kerf, we loaded up CorelDraw, and made a 1 inch by 1 inch square.
We then vector cut the square
To test the kerf, we loaded up CorelDraw, and made a 1 inch by 1 inch square. We then vector cut the square and measured the dimensions with calipers.
These are the settings on the laser cutter that we used for this test.
This is the square cut out in the kerf test.
This is a picture of us measuring the kerf using a caliper.
Joint Clearance Test¶
For the joint clearance test, we designed a series of rectangles inside a rectangle in CorelDraw and used Virtual Segment Delete to make each of them a slot for a square. Each slot was a different size, ranging from 3.5 mm to 3.9 mm. We made sure that the line thickness was hairline for this part, so the shape would vector cut. We also added the number labels, but those were not hairline because we wanted those to raster engrave. The goal of the test was to choose the best size the thickness of cardnoard to have a snug but not too tight fit.
This is the design we used for the joint clearance test without the rastered numbers.
This is the cardboard cut of the test.
This is us performing the test.
After testing the cardboard square made in the kerf test in all the slots, we determined that 3.7 mm had the best fit out of all the other measurements.
Joint Types¶
I referenced the documentation of Collin Kanofsky, Kabir Nawaz, and David Vaughn.
Fusion 360 Sketch¶
-
Press-fit joint
- Create square
- Add inwards lines
- Delete outside line
- Duplicate
-
Chamfer joint
- Duplicate press fit joint
- Apply chamfer
- Duplicate
-
Snap-fit joint
- Duplicate press fit joint
- Create outwards arcs
- Create inwards tab below
- Duplicate
-
Flexure joint
- Duplicate press fit joint
- Create symmetrical rectangles
- Create outwards arcs
- Create inwards tab below
- Duplicate
-
Wedge joint
- Duplicate press fit joint
- Create symmetrical rectangles
- Create outwards arcs
- Create inwards tab below
- Duplicate
-
Snap joint
- Duplicate press fit joint
- Connect line
- Create outwards tab below
- Create symmetrical rectangle in the center
- Duplicate
- Remove tab in other sketch
- Connect lines
- Create symmetrical rectangle in the center, larger than first in length and width
-
Finger joint
- Duplicate press fit joint
- Connect lines
- Divide top line into eighths
- Create alternating tabs inwards and outwards
- Duplicate
- Flip vertically if desired, more aesthetic appeal
-
Pinned joint
- Duplicate chamfer joint
- Create sideways inwards tabs on the chamfered edges
- Create symmetrical rectangle in center of square
- Duplicate
-
Finish
- Finish sketch
- Move sketches closer to conserve space
- Save
Laser Cutting¶
Tyler Russell confirmed that CorelDraw supports .dxf files from Fusion 360. He also reminded me of preference modification for the laser cutter, which could be dangerous if unchanged.
-
File exportation
- Export as .dxf
- Put in Google Drive
- Access on computer attached to cutter
-
Cutting
- Download as .cdr
- Ensure hairline cut throughout
- Modify preferences to cardboard
- Send to laser cutter
- Start cut, following safety precautions
- Take out when finished
I encountered the issue of poor space estimation. CorelDraw kept sending an update notification whenever I tried to send it to the cutter. However, I learned that I can bypass this and start the job. With proper dimensions on the preview, I can move and estimate the space properly. Unfortunately, since I chose scrap cardboard with cuts on the side, a couple of joints required a redo. Doing so was not difficult after sorting what I have not done and deleting the rest to recut the job.