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Laser Post-Mortem

A project log for MultiBot CNC v2

A low cost 3D printed CNC that can be built with minimal tools yet is capable of great things.

David TuckerDavid Tucker 05/07/2021 at 04:590 Comments

It is time to take stock of my laser add-on.  Right off the bat I have to say the laser is a lot of fun. It is deceptively simple to use, that can really lead to issues if you are not vigilant.  It takes almost zero setup, once I set the focus height I can add a new sheet of stock any time with little more than a rough alignment under the laser before starting a cut.  And cuts are quiet (thanks to my new air pump) and generally fuss free.  No need to worry about cut order, or to secure the material or really worry a lot about feeds and speeds.  Another plus is the accuracy, this has a 0.1 mm kerf and can easily cut paper thin slices of material, there is no worrying about splintering or dealing with a wide bit.

On the negative side, this is too easy, it is tempting to not wear the safety glasses or not remain in the room while cutting, It feels too safe.  I have had to impose some rules for using the laser to help keep myself from growing complacent.  The first rule is if the laser is plugged into the wall then I wear my safety glasses, no exceptions.  Next I go through a fixed startup sequence of turning on the air and then my exhaust fan, setting the focus and outlining my cut before I turn on the laser.  The reverse sequence is followed as soon as the cut is complete.  Most importantly I pull the power before messing with the material. 

It is also very slow, a CO2 laser would be able to cut much faster, and much thicker materials as well.  It took several minutes to cut out the little boxes from my last two posts and those are about as simple a cut as you can make.  However for the price and my applications the speed is not that bad.  I don't have room for a CO2 laser, nor do I have anything major I'm producing so time is not money in my case.

It does not compare well to a 3D printer, they are really designed to do very different things.  The laser is very much a 2D cutter, basically a drag knife on steroids.  While the 3D printer is mostly used for complex 3D forms.  This is closer in spirit to the CNC, but it is much simpler to setup and operate.  If it was not for the death ray and smoke it would be quite user friendly!  You really need to think hard to turn a 2D cut into a 3D shape, going beyond simple box like structures takes a lot of creativity, but there is still a lot you can do with just a 2D cut. I'm beginning to see the appeal of a cricut cutter, it is lower risk than the laser yet capable of cutting a lot of the same materials.

The important thing to keep in mind is that this is not a 3D printer, it is very easy to use, but not very safe.  Fire is always a concern with any tool, 3D printers included.  But here we are actually catching an object on fire on purpose in a controlled way.  It needs to be taken seriously for sure.  However if you are vigilant then this is both a fun and rewarding tool.

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