We are creating a new course (PRG-G) at the Lucerne University. This course teaches C programming and is part of the new curriculum in EE (Electrical Engineering). Every student will receive a microcontroller board on an extension board as give-away, in a custom card box for the board and cable. To make things a bit more exciting, why not laser engrave that box? That gives me a perfect excuse to experiment with the laser cutter 🙂
A laser cutter can be used (as the name indicates) for cutting materials. With reduced laser power or if the laser beam does not go through, it can engrave materials. So the idea is to use reduced laser beam power to engrave card box material.
We have 1mm card box material. Below a pile of foldable sheets for a total of 80 boxes:
The first idea was to use laser vector engraving with reduced power not to cut through the material, but to engrave writing and a logo. Below a first test enclosure with vector engraving (25 mm/sec @ 5% laser power):
It did not cut through which was intended and was pretty fast (2.5 minutes). Round paths were fine, but some path showed laser head mechanical oscillation:
The problem is that the air assist tends to blow out smaller pieces.
The next version is using raster engraving: the graphics is put on the target line by line like a bitmap image. The upper line of text has been engraved with 150 mm/sec @ 5% laser power and nearly was cutting through. So I reduced the laser power to 3% for the lower part:
Raster engraving takes longer. With 5% the writing is clear, but tends to cut out, and with 3% the look is not ideal neither.
So raster engraving was not ideal, and normal vector engraving did cut out things even with the lowest laser power I can use (2%).
Using Dashed Lines
The solution was to use dashed lines: that way the laser could cut through through and pieces or parts of the letters do not fall out. From the first design the amount of text has been reduced to have a cleaner look:
K40 Whisperer V0.5 has been used to engrave the box:
Initially I used 2% laser power with 10 mm/sec and with this the laser was cutting through the material. So I had to increase the speed to 20 mm/sec: that way the laser did not cut through and the process was faster too (around 2 minutes for a box).
Below the first box engraved in the laser machine:
Engraving card board material is one use of a laser cutter. With a combination of low laser power and moderate speed good results are possible without cutting through the material. To avoid cut-outs I have used dashed lines which worked fine and gives a distinctive look.
Happy Cardboxing 🙂