Category Archives: 2.x Laser build

More Laser Progress

The laser is fully operational.  Some additional modifications and additions will be made before the skins are installed.  When the DB-9 connector breakout boards were rewired, during the desoldering of the stranded wire that was used initially, some of the pads got lifted and I couldn’t make a connection to the trace.  I ended up having to solder some of the wires directly to the pins.  I got new DB-9 breakouts with screw terminals instead and installed the male one.  Some communication error between me and Michael regarding ordering females over the internet caused a delay in the acquisition of the female one but it has now arrived.  I will install that in the next couple of days.

Mach 3 is controlling it but I have only cut things using a little workaround for using g-code that was generated for a router via cambam or makercam.  This involves setting the z axis control output to the laser trigger pin.  If you make your toolpaths with the minimum but nonzero cut depth, safety height, and step down increment, there is very little delay between turning on the laser and moving.

There is still an issue with the nozzle for the air that needs to be worked out.  The threads for the set screw may need to be redone.  It is hard to get the nozzle aligned properly and the set screw to hold it in place firmly.  If the nozzle isn’t aligned it interferes in the path of the beam and causes the focused beam to be smeared out or blocked entirely.

Additionally, a switch for the PWM control option needs to be put on the front panel and the power wiring needs to be finished for the back panel so everything runs off of just one plug.  At the moment, the high voltage power supply and the supply for the interface board and water pump are running off the din rail.  So any time the laser and interface board are powered on, the water is running.  The air compressor needs to be plugged in separately to the power bar that is running the computer.  Do not fire the laser without air running or you could damage the lens.  The radiator fans for the water aren’t currently plugged in, but I’m going to take some temperature measurements of the water while it is running to determine if that will even be necessary.

The potentiometer control for the power currently allows you to put more than 20 mA through the laser while running it.  It is rated for 18 mA continuous current and while putting more through it wont blow it up or anything, it will reduce the lifetime of the tube.  I am going to install some additional series resistance to the potentiometer control circuit to limit the maximum allowed current to 20 mA.

Here’s one of the first good cuts, it’s kind of hard to get good pictures of clear acrylic though.

laserlogo4small

laserlogo3small laserlogosmall

Laser progress

Last weekend I looked over the stuff that I was still unsure about for the laser.  I found the nozzle for the air assist and Aaron drilled and threaded a hole in it for the set screw.  I wanted to get the wiring done for the limit switches but there was a class going on that made the equipment inaccessible.

This weekend I want to get a couple things done.
1. Wiring for the limit switches (first thing in the Wiring section).
2. Design and cut (CNC) a front panel (first thing in the Additional Notes section).  I will use a thin piece of wood to test it and then we can cut a metal one with the new CNC machine once that is running.  We also need to decide exactly what will be on the front panel.  There are several options covered in the two sections linked above.
3. Adjust belt tensions (#6 in Additional Notes).

As far as things that we still need that we either don’t have or I can’t find, this is the current list.
1. Air pump.
2. Tubing to connect water pump to laser tube.
3. Potentiometer for laser power control (for front panel).
4. Air pump switch (for front panel).
5. Bed/Platform for placement of things to be cut.
6. Optional items for front panel – key switch, button switches for manual firing, pwm control switch.

2.x Laser

This is mainly intended for hack.rva members that are interested in finishing building the laser.  I made a page with a bunch of sub-pages to organize what is left of the build.  If anyone has input you can email me or just comment on this post (I don’t think you can comment on the actual page).

https://computationalphysmatronics.wordpress.com/projects/2-x-laser-build/

If any random internet person that stumbles across this has any constructive feedback or input on the project, especially if you have done something similar, feel free to comment here on this post as well.