Computer-Controlled Cutting
This week I will utilize 2D CAD tool, to design a press-fit laser cut structure. As I am trying to figure out how to build my final project, an emergency shelter, I decided to design a 2D press-fit shell-ish structure with cardboard, as a proof of concept. The first configuration that came to my mind was polygon mesh.
Polygon mesh is the most common approach for digital 3D graphic:
A polygon mesh is a collection of vertices, edges and faces that defines the shape of a polyhedral object in 3D computer graphics and solid modeling. The faces usually consist of triangles (triangle mesh), quadrilaterals, or other simple convex polygons, since this simplifies rendering, but may also be composed of more general concave polygons, or polygons with holes.
My idea is, you can build literally anything with triangular mesh in digital world, why not try translate it into atom world?
Before I did any design, I first reviewed the laser cutter in FabLab Taipei, an Universal VLS 4.60. We have a 13-point guideline for laser cutter in the lab.
Short Version:
Calibrate the height of the nozzle and do the focus before any work
Make sure all the ventilation is powered on before cutting
Clean your own s*it after your work
And last weekend was Valentine's, so I exploited a heart-shaped box design from Thingiverse, as a part of surprise to my girlfriend.
I tried Antimony in week 2, and fascinated by it. So I decided to do a little more playing with it.
Yet because I cannot figure out how to do the design with precise measurement, which is crucial for press-fit design, so I just use it to quickly test the concept.
Then I turned to Inkscape, and use the "clone" feature to replicate the triangular shapes - the faces for the polygon.
Also with wedge (in purple) as bridge to connect each polygon.
Last steps: convert the drawing into "stroke" only, at 0.025mm width, which is required for vector cutting on a Universal laser cutter.
And remember to export the file to .pdf the reason is we have some problem when saving as .svg, the size shrinked a little bit on cutting.
I chose cardboard that salvaged from an used carton.
At the first glance it looks great.
However, the random cardboard we found in Taiwan actually created lots of fume during the cutting. And left black particles. Jason Wang gave me a hint during regional review, that is, cardboard needs lower power, so I might give it a second chance to build some revision.
In our lab we have two vinyl cutter, one is GCC i-Craft, the other is Graphtec CE6000-60. For the practice I chose Graphtec one because it only needs one software installed on Mac, and GCC needs more than one which I think is not so user friendly...
Anyway, this is the machine:
the blue bars on the rail is for identify roller positions, also for media width.
control panel
the lever is for lock / release of the vinyl, the position in the photo is lock. If you needed to change media or fix jams, just set the lever to release by pushing it down.
at the rim of the cutter, there are a series of tiny holes, inside I think it should be light sensors, so the machine itself can detect the width and length of the media automatically.
I randomly downloaded a Stark sigil from Game of Thrones, and import the file to Graphtec Studio
For the tutorial I really recommend this Youtube video:
The result was not good, reasons:
1) the speed of the cutter was too fast
2) the cutting force might be too high
however I tried several configuration still looked not so promising...
3) the contour was too complicated with all sharp turns
Out of anger I chose a Chinese character pronouced "GAN 4", it can be either "do", "make", "stem of a tree", "centerpiece", or my favorite, "fuck", "fuck it" or "damn it" in Taiwanese language.
Bonus: Taiwanese (Chinese) Crash Course for you.
If you planned to come to Taiwan, please make sure you understand the usage of this useful and powerful word.
The contour of "GAN 4" is much simpler huh?
Using the same parameter, it was a sucessful cut. Lesson learned, don't use vinyl cutter to cut profile full of sharp turns.
Me wearing the "GAN 4" helmet.
Link for designs:
