# Group 3 : Testing Acrylic

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### Testing kerf

There are two ways to test kerf.
One: cut a square of wich you know the the dimensions you have drawn, and then measure the dimension after cutting. The difference is twice the kerf. Twice because if you measure lenght or width, you actually measure the material that was burned away twice. We drew a square of 40mm by 40mm and cut it at Speed: 20. Power: 100.Then we measured the width (or length, it's a square).

So twice the kerf is .25mm, making the kerf .125 mm.
The second way to measure kerf is to cut 9 bars of your material, so you actually cut 10 lines that each have a kerf. If you take the mean of these 10 kerfs, statistically you should obtain a more acurate kerf. Statistically. Practically the bars have a way of slipping away and overlapping eachother and on top of that it is really hard to get your caliper in between the bars and the framework you have drawn and cut. The framework is flexible so it backs away if you push in your caliper.

As you can see 10 times the kerf here is 1.84mm, so kerf is .18mm. This is bigger than the kerf we measured with the square. Because of the practical issues I descibed aboved, I would go for the kerf derived from the square.

### Testing engraving

To test the best cutter-settings for engraving acrylic we first drew a template with Adobe Illustrator.

After drawing the template, we put stroke to RGB black, fill to none and the weight to ,1 pt. As you can see here:

After this we selected all and expanded the template as you can see here:

Now you can save the file as Illustrator CS6, put it on a USB and then take it to the laser cutter computer.There you save the file in the FabAcademy2018 folder. Then you open the laser cutter software and import your file. Now you can select the different squares and each give them a different colour (at the bottom of your window). Every colour stands for another setting of speed and power. It looks like this:

As you can see in the template we used the same speed; 350 and varied the power 20, 40, 60, 80 and 100. Now the document is ready to go, you chose download and download current. Then you put the material into the cutter and direct the laser to a place you can start cutting. You do this with the arrows on the machine. Make sure the machine has power. Calibrate the hight of the laser with the wooden tool provided. Then press "Test" to see if the cutting area is completely on your material. And then turn on the ventilation, turn on the laser and press START. After cutting it looked like this:

Conclusion: S350 and P20 makes beautifull engraving in acrylic.

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