I bought a 2500mw Laser kit from Banggoood.com.
I waited a few days the started making upgrades. First recessed the gantry screws with 6mm X 16mm flat head allen screws.
Cut the controller mount loose using the desktop mill from the back legs and mounted it on the gantry.
Used USB cable and some micro switches to make up homing switches. Soldered to the back of the controller board to get an I/O for the switches.
Added a wire drag chain to it and some rubber feet. when moving fast it would slide all over the table and screw up the engraving. It only has about $10 worth of installed upgrades on it! There will be more upgrads in the future. Looking at either adding code controlled focus or Z axis to keep the beam in focus as it cuts deeper. Designing a Multi-Diode Laser assembly. This allows you to have two cheaper Diodes, used as one beam, rather than a more expensive single Diode. also should add flexibility as you can shut one diode off for things like engraving where you do nt need as much power. Planning on using a Tablet as the control just as I did an the Printrbot Play 3D Printer.
Some of the upgrades have been done so far in a manner that allows others to carry them out without all the equipment I have. Later these will be redone usin things like the 3D printer to make mounts for the Drag chain as an example.
I have an Upgrade Controller on hand. It is an Arduino Uno/CNC shield boards from Banggood. The Uno does not have any more power than the Arduino Nano used in the stock board but the the 4 axis CNC shield means you do not have to solder into it to get access to the I/O pins. And it has the extra axis for the focus or Z that I will need later. I also have a TTL board from Banggood this allows better PWM control of the Laser. The Stock Laser driver boards are somewhaty iffy when it comes to PWM control. I am looking at replacing the stock lens with an upgrade to a glass lens or the G2 glass lens.
You can see more of this and other DIY kit lasers at BenboxLaser.US
There will be more later!