3. Computer controlled cutting – Group Kuriyama¶

This is group assignment page of Computer-controlled cutting (Kuriyama Student) :

Group assignment¶

Characterize your lasercutter’s focus, power, speed, rate, kerf, joint clearance and types

What we’ve done this week¶

Researching on focal point of lasor cutter
Validation of Parameters
Proper kerf measurement for 3mm cardboard

Researching on focal point of lasor cutter¶

The lasercutter we used is Trotec Speedy 300

When processing with a lasercutter, first measure the focal length👍

Set it in the processing area and focus the laser.
- Keep a sufficient distance between the lens holder and the processing table (a distance that does not interfere with the attachment of the focusing gauge) and attach the focusing gauge to the projection of the lens holder. The focusing gauge will hang freely from the projection.
- Raise the processing table with the height adjustment button. At this time, be careful that the nozzle tip does not come into contact with the surface of the processing table (material surface).
- When the focusing gauge contacts the surface of the processing table (material surface), the gauge will be detached from the lens holder. At this time, the processing table will be at the correct focal length height.

Next, We measured the focal length.

The results are as follows

Validation of Parameters¶

The laser has three parameters, Power, Speed, and PPI/Hz, which can be changed to cut a variety of materials.

The following table shows the minimum and maximum measured values of the laser cutter parameters

	Power	Speed	PPI	Hz
Min	0.01	0.01	500	1000
Max	100	100	60000	60000

In this case, we used 3mm cardboard as the material and found the appropriate values for 3mm cardboard 📦

First, we fixed the power at 20 and the Hz at 1000, and varied the speed to see where we could cut.

No.	Power	Speed	Hz
1	20	10	1000
2	20	8	1000
3	20	6	1000
4	20	4	1000
5	20	2	1000
6	20	1	1000
7	20	0.8	1000
8	20	0.7	1000	push it out with fingers, it will cut off
9	20	0.6	1000	Can be cut

Next, We tried changing the speed value to measure at what value the power would not cut well.

No.	Power	Speed	Hz
1	30	1	1000
2	29	1	1000
3	28	1	1000
4	27	1	1000	push it out with fingers, it will cut off

Next, We tried changing the Hz value

We tried changing the value of hz to see what would change, but saw no change.

No.	Power	Speed	Hz
1	20	1	2000
2	20	1	3000
3	20	1	4000
4	20	1	5000
5	20	1	7000
6	20	1	10000
7	20	1	20000

We didn’t know the difference, but the instructor, Mr. Toshiki Tsuchiyama, told us the following

Generally speaking, the larger the distance and time between successive pulses, the better the machining time, in order to prevent residual heat, plasma, and machining debris. The distance depends on the speed of the scanner, and the faster the scanner speed, the larger the distance between pulses can be, but the faster the scanner speed, the lower the positioning accuracy. The time depends on the frequency of the oscillator, and the lower the frequency, the better the processing condition, but the longer the processing time.

Precision Hole Forming with Ultrashort Pulse Laser (JPN)

We thought that by increasing the Hz value, the cross-section would be cleaner and it would cut through more cleanly. But in fact, the secret was to decrease the Hz value and reduce the processing speed to get a clean cut.

When the data is too detailed (many paths) as you can see in the image below, you need to lower the Hz value and also lower the speed (adjust the power value accordingly).