Week 3 notes Computer-Controlled Cutting

This page documents the group assignemnt for week 03 of Högni and Jóhannes.

Vinyl cutting

Safety Information

Basic Setup

Cutting

The files for vinyl cutting are vector graphics saved as pdf file where the line width is 0.02mm.

We did the first trial with Jóhannes design file on green vinyl.

Vinyl Cutting Test

Laser cutting

Safety Information

Basic Setup

Power vs. Speed

We started with acrylic sheets of 3mm thickness and made a rastering and cutting test in some iterations.

Here is a picture of what we intended to cut. (original file from Ólöf, modified by Jóhannes)

Power Speed 1

We wanted to use color mapping to adjust speed and power for all the boxes and do rastering and cutting in one step. However we had to learn, that the colormapping function has a limit of 16 colors. We then defined the first 16 colors and discovered, that the other colors are then rastered with standard settings. We also realized that the speed for cutting needs to be much lower, so we cannot use the same settings for both operations
Then we reduced the number of boxes to 16 and adapted the color mapping and settings. However, because it is a lot of manual entering of numbers we made some mistake and had produced one more scrap piece.
Now we did want to get it right. We repeated the procedure from nr. 2 but with the right numbers entered and it finished nicely. Here is a screenshot of the file and the result.

Power Speed 2

Power Speed 2 result

Link to the cut file.

The results show cutting through the material starting from ??? Power and ??? Speed.

Kerf and clearance

Then it was time to make a kerf and clearance test. We used 7% speed and 100% power for cutting the acrylic sheets.

The test file Jóhannes made looks like this.

Kerf & Clearance 1

We measured the kerf gap which was 2,2 mm what results in a kerf of 0,22 mm.

Kerf measured

Then we realized, that the fit of the comb was way too loose. We measured the sheet and it was only 2,7 mm thick. That is of course fatal for fits that need an accuracy ogf 5/100 mm.

Now we reduced the the starting size and took into account the kerf and the below-spec sheet thickness.

This is the new file and the result:

Kerf & Clearance 2

The result shows a clearance of -0,05 mm resulting in a good tight fit.

As the MDF sheets we also wanted to test, have a measured thickness of 4,0 mm we reduced the comb dimensions for the 4 mm side less then on the 3 mm side.

Then we repeated the procedure with the MDF and got the following results:

Kerf: <!-- Högni?>

Tight fit clearance: <!-- Högni?>