This assignment is about characterizing the laser cutter's focus, power, speed and kerf
Measuring the focus
We started by measuring the focus of the machine. The focus is the smallest dot the laser makes, so we leveled the bed up and down until we reached the smallest dot then we measured the distance between the nozzle and the material which is around 6 mm.
Characterising power and speed
In order to characterize the cutting/engraving power and speed for the laser cutting machine, we designed a part that has rectangles to be engraved/cut with varying parameters of speed and power. The engraving speed is constant and set to 300 mm/s meanwhile the engraving power varies from 15% to 95%. In the case of cutting, the power is set constant to 65% meanwhile the cutting speed varies from 50 mm/s to 20 mm/s.
The results are shown in the following image. showing that the cutting speed is around 30 mm/s and the cutting power is 65%. The engraving power variation is also shown in the image.
Kerf and clearance measurement
To measure the kerf and the clearance, we designed a comb part that has slots with width varying from 2.8 -> 3.2
We cut the part on the laser cutter using the proper cutting settings above and tried to fit the comb together. the comb fitted a hard fit in the 2.8 slot, however fit a proper fit in the 2.9 slot. we approximated the kerf to be between 0.1 mm and 0.2 mm. To measure the kerf we substract the slot width from the material thickness.
We have also designed another part to measure the kerf which is shown below. it is a rectangle containing small rectangles inside of it.
Then we cut the part on the laser cutter and joint the small rectangles together, to discover that there is a huge gap as a result from summation of the kerf in each slot. We measure this gap and divide it by the number of the kerf lines presented in the design to get the average kerf which is 0.15 mm.
We measured the gap by measuring the width of the rectangles, then measure the width of the whole part. the gap width is the width of the big rectangle - the width of the small rectangles. the kerf is approxmiated by diving the gap width by the number of lines.
Students contribution
We asked the students characterize the kerf on different materials like cork, acrylic, mdf. each student did the same measurements we did on the 3mm plywood but on a different material. Here are samples of the output of the students work.