Computer-Aided Cutting
Table of contents
Group Assignment for Laser Cutting
Characterize your lasercutter’s focus, power, speed, rate, kerf, joint clearance and types.
As shown in Week 1 of our Group Assignments section, we cut a series of test pieces to characterize our lasercutter’s power, speed, rate, kerf, joint clearance and types.
| Parameter | Initial Group Values | Final Optimized |
|---|---|---|
| Focus | Using Focus Tool | Using Focus Tool |
| Power | 75% | 80% |
| Speed | 10% | 16% |
| Rate (PPI) | 1,000 | 500 |
| Kerf | 1.14 mm \(\big(\textstyle\frac{2.27 {\rm mm}}{2}\big)\) | 1.14 mm |
| Cardboard thickness | 4.2 mm | 4.2 mm |
- Kerf is the width of the cut, which is the width of the laser beam. And it is calculated by cutting a rectangle and then measuring the width difference between the acture cut and the given size. The kerf is the half difference, since a rectangle is cut on two sides. And the offset would be the half of the kerf.
- The measured cardboard thickness is 4.2 mm.
- The final optimized values are evaluated by successfully cutting a hinge pattern with the distance of 1.5 mm. The laser cuts through the cardboard without causing a fire.
Vinyl Cutting
Vinyl cutting is a cool tool to deploy 2D graphic design (e.g., brand and label) on real-world objects. I manually turned some of my favorite photos into vector graphics and then cut them out with the vinyl cutter. The steps are shown below as well as figures as the step-wise results.
Steps and Results
 1. Use Adobe Illustrator to track silhouette of the target image |
 2. Convert to vector graphics (.SVG) |
 3. Print using the Vinyl cutting machine |
 4. Use a transfer tape and a tweezer to get out the sticker and deploy it on a surface |
Photo Booth of Vinyl Cutting
 Queen Elizabeth II (1926-2022) passed away weeks ago (Sep. 8, 2022). Photo from WSJ. |
 Roger Federer with (one of) the best single-hand backhand and volley techniques in tennis history, annouced to end competitive tennis career after Laver Cup, London 2022. Photo from checkdownsports.net and WSJ. |
 Li Jian and Zhou Shen impromptu singing. Photo from weibo. |
 Compound view |
Laser Cutting
Laser cutting is a powerful tool to enable 3D construction from 2D design. I first designed a laptop/iPad stand using Fusion 360. Then I cut it out with the laser cutter. And finally I assembled the stand and show some photos of it along with use cases. I am actually intrigued by how can we assemble a non-planar surface with laser cutting, where the hinge is a good example.
Parametric Design of a Construction Kit
Following a simple tutorial, I managed to design a parametric construction kit for a laptop/iPad stand. The design is parametric in the sense that the user can change (almost) all the parameters of the stand before sending it to a cutting machine, especially the thickness of the material, the length and the angle of the stand. The design is shown below in Fusion 360.
A nice embedded view of Fusion 360 is shown below.
The parameters controlling the design are shown below. The user can change the parameters and then send the design to a cutting machine. The cutting machine will cut out the stand based on the parameters.
Laser Cutting of the Construction Kit
I then extracted three sketches (stand×2, top×1, and support×2) to .DXF files and sent them to the laser cutter. The laser cutter cut out the stand based on the parameters. The cutting process is actually satisfying, as shown below.
The first trail was unsuccessful, as the estimated cardboard thickness (8 mm) as way too large for the stand to be assembled together. I then reduced the cardboard thickness \(t\) to 4 mm and redo the cutting. Thanks to the parametric design, I just need to change a single value \(t\) in Fusion 360 and everything else is magically done. The second trail was successful, as shown below.
 Failure first trial because of wrong cardboard thickness. |
 Successful second trail after change \(t\) in the parametric design. |
Photo Booth of the Construction Kit
 Demo as a laptop stand. |
 Demo as an iPad stand. |
Non-Planar Surface with Laser Cutting
Inspired by the hinge construction to assemble a cylindrical surface with laser cutting, I designed to test the curvature using different spacing of the hinge, as shown below.
 Hinges with spacing as the parameter. |
 Printed hinges. |
It turns out that only the smallest spacing (1.5 mm) can successfully cut through the cardboard, and it can be bended flexibly as shown below, which can be a storage box for the iPad.
Further Extension
Following the idea that different hinge spacing would result in different curvature. We can manually design a gradually decaying hinge spacing to achieve a smooth non-planar surface, such as a sphere. Furthermore, by bringing in the Gaussian curvature in differentiable geometry, I envision that we can a arbitrarily curved surface. That would be a research topic for computational fabrication and geometry.