Hey y’all,
For the 4th assignment the task was to laser etch and cut the Rice war owl with a partner. Seems pretty simple but it actually took a lot of work to produce a good owl.
Laser cutting is a manufacturing technology in which a focused laser beam is directed at the material, which then either melts, burns, vaporizes away, or is blown away by a jet of gas, leaving an edge with a high-quality surface finish. There are two basic operations that can be performed with a laser cutter: cut and etch. The settings of power and cutting speed of the equipment will determine if the laser will pierce the material and cut or if it will only consume part of the material thickness and engrave. Slow speeds and high power configuration make the laser consume more material. To learn more about laser cutting click here.
The War Owl produced should be aesthetically pleasing and a viewer should be able to look at the piece and recognize the object as something very similar to the original War Owl. e. There should be minimal to no charring, the edges should be clean, and the part should have the correct geometry.
The equipment used was a BOSS LS-3650 laser cutter with the Engravelab software. In this software the configurations of power and speed of the laser were set for the different areas of the owl. The challenge of this assignment was to determine what configuration produced the best result, with good contrast between the layers and minimal charring.
Now our saga starts:
- First test
Following Dr. Wettergreen recommendations, Brian and I started by testing the laser cutter configurations.
In this test we etched multiple circles with cutting speed of 400 and power ranging from 10 to 80. We had a problem that the machine or the program would crash if we had more than 5 layers to be etched in the same file, that is why the test was divided in two pieces.
After analyzing the circles engraved in the first test we decided the configurations of the first owl.
2. First owl: the one in a wood board
The first war owl we etched did not go very well, the contrast is not good and it is burnt because we choose very high power settings.
Also we concluded that it would be better to cut the contour of the owl from the wood instead of leaving a board, as we did on the first one, because we would not have to worry about the contrast of the owl with the board.
3. Speed and power test – again
Since the first owl did not look as we expected, we decided to run another test. This time varying both power and speed. We run this test with speed varying from 400 to 600 and power from 10 to 100.
From this test we realized that the speed configuration did not make a relevant difference in the color and that power configurations above 30 will cause the wood to burn.
4. Testing (for the last time)
The last test was performed with speed at 400 and power configurations between 15 and 30 with increments of 2.5 to evaluate if we could get good contrast with small increments in power.
The test confirmed our hypothesis, even a small difference of 2.5 in power was able to create good contrast. After this test we decided we were ready to etch another owl.
5. Owl etching – second try
Our second owl was made with lower power configurations as shown below:
Different from the first try this one did not have a board and the owl contour should be cut off the wood. But the problem with this piece is that not only the contour was cut form the wood but all lines in the original drawing were cut. This is the result:
This problem happened because we set the green area (shown above) to be cut and the right procedure would be to leave this area with no engrave configuration and use the contour function in the Engrave lab software.
6. Owl etching – fail again
After figuring out what went wrong with the last piece and using the contour function on the Engrave lab we made another owl. But we did not use the contour function correctly what resulted in the laser cutter cutting all boundaries again!
(no pictures because it was really frustrating)
7. Owl etching (x4) – it is getting better
For the next owl we learned how to use the contour function correctly. Also, to avoid waste of time and material first we made a small owl to be sure that only the contour would be cut.
Finally we made the contour correctly!!
So we moved on for the next full size War Owl:
It turned out to be a pretty good piece despite some imperfections in the material. There was only one problem we observed: because of the heat of several laser operations on the same wood board (the whole class was doing its owls in the same wood piece) the board was bent, this caused one side to be darker than other and the laser did not pierce the material in the entire contour. So to remove the owl from the wooden plate we had to break the part that was not consumed by the laser, this caused some imperfections on the edges.
8. Owl etching – better material, same problems
To obtain a better piece we looked for a better wood board, plain and with less defects. We engraved the war owl in this board using the same configuration of the last owl:
However, this board was thicker than the first board and the laser could not pierce trough the material. Again when we took the piece out of the board some defects appeared
9. Owl etching – the last and successful one
After decreasing the cut speed, we engraved another War Owl. This time the laser pierced the material in the entire contour and we did not have to break the wood to take the piece out.
The last piece looks very good with good contrast, clean lines and almost no charring as one can see in the picture:
Our final power/ speed configuration were the following:
Sigh!
After this assignment I realized that using a laser cutter requires a good amount of experience. The power/speed configurations might look simple at first, but achieving a good looking final piece requires expertise to set the engraving and cutting settings properly.
I believed that Brian’s and mine final product is very good and I am proud of it. The piece really resembles the original war owl with good contrast and no parts burnt. It took a long time to produce the final piece and the process was frustrating sometimes but I learned a lot and believe I am prepared to use the laser cutter for future prototypes.
I hope you guys like the final War Owl as I do. Thanks for your attention and see you next time!
Lucas Gutembergue da Costa
