Wednesday, June 1, 2016

Solid State Laser Engraver Overhaul

I had a lot of free time on my hand when I was laid off in January of 2015. I needed a project to work on to keep myself from going crazy while I was still looking for a job. I have a tendency to have about 15 project ideas floating around my head at any given point, a side effect being buying random parts for any one given project over time, and then those parts lying around for a while. It makes having all the parts I need for a given project already in my work-space a common occurrence. This was the case for my laser engraver/cutter. I had at least 90% of the hardware that I needed to build the project, which was good because I had to keep the cost moving forward to an absolute minimum. Here is the final result.


Yeah I know, not very pretty.

I use ball bearing drawer sliders, and Nema 17 stepper motors with direct drive 1/4 20 threaded rod. The main structure and all connecting pieces are made of 3D printed parts and 3/4" square aluminum tubing. I use a "2.5W" 405nm laser diode. It works fairly well, but has a small working area and banding problems. Even with these short comings I was able to get a few fairly useful projects out of it. I was able to engrave my name in leather for a couple cases. I also helped my friend cut out poster board stencils used to make road markers for his wedding. I also used it to make a custom Munckin board for my wife. (Not perfect, but still pretty cool)

I was never completely happy with its limited use, and have been wanting to remake it larger, and more capable for several months now.

These are my general guidelines:

1) Get rid of the threaded rod and use belts
2) Increase the work area to fit a sheet of dollar tree foam board
3) Increase laser power (Still solid state, more on this later)
4) Improved ventilation
5) Be able to make grey-scale images (Raster Etching)
6) Software controlled laser power
7) Laser Z-axis control for material differences and multiple pass cutting
8) Improved control hardware enclosure and functionality

Going with belts makes it significantly easier to increase the functional area of the laser, especially with 3D printed parts. It also makes alignment easier, and speed at which I can move the laser head. I am going to use some parts that were designed as replacements for my solidoodle 2 for the longest axis. They use (bearings from amazon)

I am currently using GRBL on an arduino for control, and have been happy with the performance and ease of use, so I don't see a need to change. There are also distributions for the raspberry pi that are made specifically to interface with GRBL and use a web interface. This is also the direction I plan on taking, eliminating the POS macbook that I bought for 100$ 5 years ago. Yeah, still regret that decision, but it was a functioning machine I could leave attached to the laser.

Update (6/1/16):

I started this blog post several months ago, and like many things it has sat unfinished for quite a while. Recently, I have made significant progress on the cutter and am pushing myself to somewhat document what I have done on here.

The next post will contain as many pictures as I have of the progress so far and how things are progressing.

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