Computer-Controlled Cutting

Assignment group

Characterize your laser cutter, making laser cutter test part(s), making test part(s) that vary cutting settings and dimensions (group project).

To do:

1- Characterise the lasercutter .

2-Complete write-up.

3-Make a webpage for this.

We get introduced to the laser cutting machine. We get to explore different ways of making 3D structures with only 2D tools.We were 9 and we have been divided into two group.The aim of the group work is to find the “Kerf”. The laser machining process produces a cut with non-zero thickness. This means any assemblies requiring tight tolerancing have to take this into consideration. This is gap called 'kerf'. It varies depending on the material, thickness of the material, focal length of the laser lens and the power setting of the laser.

In the lab they have Universal Laser Systems this is the types. Features: 150W ILS 12.50D at present running on 75W only, so the settings we make will have to change when the second laser tube is fitted.

This laser cutter can cut many types of material such as Composites, Elastomers, Foams, Glass & Ceramics, Metals, Natural (Inorganic), Natural (Organic), Paper-Based, Plastics.

3mm cardboard

Eidha, Abdullah, Zahrah, Darshan

Testing different process parameters:

Well, after we identify the laser cutting machine we moved to identify the “Kerf” of the cut and below is the table showing the details of the changed we made in order to make a perfectly fitting press-fit kit.

Identifying the kerf:

So, after measuring the differences between the “original” parametric design and “test 1”, which both has same features of:

Thickness: 3mm

Length: 120

Width: 50

So, we identified the kerf as 0.05mm



Testing for a better kerf again by changing the kerf from 0.03 to 0.06 with same aforementioned thickness and width and this is the result:



After couple times of testing we reach to the end that attempt number 1 of kerf test is the best size. However, we changed the:

Power=30%

Speed=12

PPI=300


6.5mm cardboard

Salama, Bear, Carl

We had to develop some tests.Initially we tried a few tooth-type fitment tests with increments of 0.10mm - this was to try to figure out what dimension to program into our parametric software to ensure our press-fit kits would fit together nicely with a good amount of grip.



There are three main types of operation we used:

  • Etch (raster) - Etching is a partial penetration of the material. It has different effects on materials that oxidise (i.e. wood, aluminium, copper) as opposed to ones that don't (mainly acrylic). To do this we use a process called "rastering" to slice the image into passes that the laser machine will 'colour in' using the laser. This is really similar to a regular printer travelling line-by-line down an image.
  • Etch (vector) - This is the same process of partial penetration, however instead of travelling line-by-line it travels along the outline or paths of an image. In order to do this we have to 'trace' or 'vectorise' the image to turn it into paths so the laser machine can follow them.
  • Cut - This is the same as the vector etching process but by making a full penetration. Usually you need to slow the travel speed right down in order to cut through fully (especially around corners) and also it is imperative that the laser is in focus.



    • we are able to adjust settings for each type of operation. The major factors that affect the quality of laser cuts are power, speed, lens focus, flatness of the material and fume extraction (or airflow).



    What we found is that the up-down kerf can be different to the left-right kerf.The kerf was between 0.75mm to 0.2mm. If you look closely at the fitment testing we did you might notice the gap on one side is larger than the other by about 0.5mm (that's huge!).

    the corrugations in the cardboard are having an effect on the kerf size. One way to tell for sure would be to test on acrylic which has no grain to it.