Computer-Controlled Cutting¶
Goals¶
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.
Individual assignments: - Design, lasercut, and document a parametric construction kit, accounting for the lasercutter kerf, which can be assembled in multiple ways. - Cut something on the vinyl cutter.
Prior Knowledge¶
Since CAD week just finished, I count that week as preparation. I spent part of freshman engineering learning how to operate a laser cutter, and pre-Fab gave us projects since, so I doubt I will encounter any sort of learning curve.
Projected Timeline¶
- Wednesday
- Nothing (flu)
- Thursday
- Vinyl cut
- Friday
- Start group assignment
- Saturday
- Sweet 16 and school dance (break)
- Sunday
- Finish group assignment
- Start individual assignment
- Monday
- Finish individual assignmment
- Tuesday
- Correct prior documentation
Actual Timeline¶
- Wednesday
- Nothing (flu)
- Thursday
- Vinyl cut
- Friday
- Document
- Saturday
- Sweet 16 and school dance (document)
- Sunday
- Write terms and definitions
- Monday
- Joint test
- Start individual assignment
- Tuesday
- Correct prior documentation
Vinyl Cutting¶
We needed to vinyl cut our own stickers, and since I was absent on Wednesday, I spent Thursday catching up and learning the process.
Software¶
I used Sihlouette studio and pasted my screenshot of the design. I decided on a sunflower.
- Prepare file
- Open Sihlouette Studio
- Open .svg design file
- Trace
Angel Fang helped with the Quick Trace feature. I learned that I could simply select my trace area and trace the object, then delete the original. However, I was confused what to do from there, since the layers did not seem to be working. I tried creating an .svg on CorelDraw instead, which technically worked, but as it turned out I needed to trace at one point directly in the cutting software. I re-did it and it worked.
- Cut
- Place vinyl on mat
- Load cutter
- Cut by fill color
- Send to cutter
Amalia Bordoloi walked me through this, having done it the day before. I encounteered some confusion with cutting the design on the wrong colored vinyl due to not being sure which color the machine was cutting. As it turned out, one has to separate the colors after tracing and delete the original. I cut four colors - yellow leaves, an orange outline, a brown inner circle, and a lighter brown circle surrounding it.
- Transfer
- Peel stickers off of paper
- Cut out transfer tape square
- Place parts on transfer tape, using scraper throughout
- Transfer from tape to wall
The process was easier once I understood what was happening. Scaling the square to fit the stickers while being convenient required some consideration. I also found transferring the sticker design to the wall, especially the thin outline, time-consuming. Still, it was a rewarding process.
Group Assignment¶
I was in a group with Andrew Puky, Amalia Bordoloi, and Elle Hahn. I was assigned terms/definitions and the joint test. I referenced the documentation of Collin Kanofsky, Kabir Nawaz, and David Vaughn.
You can see our documentation on our group site.
However, even after finding a clearer image from their folder in the school engineering drive, I could not decode the writing. I wrote the names of the joints here to save any future Fab participants from issues.
Here it is for reference:
The words were mirrored and backwards, I believe. Anyway, I figured it out and the CAD was quite helpful. Note that I sketched these joints slightly out of order for the personal ease of movement and duplication.
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.
Individual Assignment¶
Since I never experimented with the polygon aspect of Fusion 360, I decided to make a hexagonal prism. This entails two hexagons and rectangles connecting them with a tab on each side. With the convenience of parameters, the only challenge lies in aligning the hexagons and rectangles properly.
Creating Shape¶
-
Create parameters
- Tab length/width
- Rectangle length/width
- Kerf
-
Sketch shape
- Create edge polygon
- Divide side into thirds
- Create two symmetrical inwards tabs
- Extend down
-
Pattern
- Create circular pattern
- Click center point for center
- Apply quantity of six
This process took multiple iterations of trial and error. I realized my errors throughout, most notably my first one: creating chamfers at the bottom corners as opposed to the top. I then decided that chamfering in general overcomplicated the process and creating right angles on each side helped me in the long run. Also, the circular pattern feature certainly helps. With that in mind, without changing parameters, constraints, or dimensions before creating the pattern, one spends more time undoing the pattern than they do with the rest of the sketch.
- Create rectangles
- Create 2-point rectangle with same width as hexagon, different length
- Use tab parameters to create outwards tabs to match those of the hexagons
- Duplicate
- Mirror tabs across sides and delete outwards tabs, flipping them inwards
- Duplicate outwards and inwards tab twice to get six rectangles total
This process required trial and error. Since I would realize I needed to change a parameter or shaping issue only after creating the pattern, the repetition was key.
Eventually, I created shapes that I was satisfied with. I considered other documentation and modified the tabs to be narrow for a proper fit. I also found creating mirrors and applying symmetry crucial during the process.
Cutting¶
- Download as .cdr
- Click correct plane
- Ensure hairline cut throughout
- Modify preferences to cardboard
- Send to laser cutter
- Start cut, following safety precautions
- Take out when finished
When accessing my file from CorelDraw, which normally works, it only showed up as lines. Zaina Gibrine helped me, suggesting that I choose the profile plane I sketch on. I used to keep front, the default plane. I tried top and the file worked perfectly.
Also, the hexagon burned on the first try. I re-cut in order to fix this.
Mr. Dubick noted that I needed more pieces, so I cut a smaller version. While the sides fit each other, even though I scaled everything down proportionally, the hexagons did not fit the sides.
I re-cut to fix the issue, cutting a larger version this time for convenience by uniformly using a scale factor of 1.5 about the origin.
- Assemble
- Attach sides
- Attach faces
I finished the design for both and stacked them as a decoration. The hexagonal prisms look a bit like a building.
Reflection¶
During a busy week for academics while catching up from consecutive absences, finding time became the greatest challenge. I am surprised with the momentum I’ve created these first few weeks. Still, I need to work out the CAD details for my final project. This experience and the existing files will help with my designing. Now, onto programming.
Files¶
Fusion 360: Joint Types
Fusion 360: Parametric Construction Kit
Lessons¶
- When vinyl cutting, use the computer that is connected to a vinyl cutter, not one on the desk. While I’m sure that one can export the file, I found it far easier to create it there and cut directly. You can also make changes between layers if you choose.
- Fusion 360 sketches translate seamlessly to CorelDraw for cutting. Having never tried exporting a Fusion sketch before, I already find it much easier and faster, and it only takes an extra 30 seconds to change the file format
- When making sides that alternate between inwards and outwards tabs, be sure to prevent the outwards tabs from breaking. I suggest putting all the inwards sides first and then adding the ones with outwards tabs.