I am getting to the stage where I want to be able to check the alignment of the optics on my 40W Chinese laser. Don't ask me what brand it is. There are absolutely no model numbers, makers name plates, brand names or serial numbers anywhere on it. I bought it sort of second hand but the more I dismantle it the more stunned I am at how poorly made it is. I was a metalwork teacher for 35 years and I thought I had seen some pretty crappy craftsmanship over that time but honestly, this thing takes the cake. For example, today I dismantled the X axis motor plate so that I could install some LED strip lighting under the X gantry. The hole for the stepper motor had been carved out freehand with a rotary burr! That sort of thing really bugs a mildly obsessive compulsive like me. I had to machine that hole round, even though you can hardly see it once it is reassembled.
The original first mirror mounting was just a piece of bent sheet metal and there was no adjustment built into the point where it mounts to the chassis.
- Here is the original mounting for the first mirror. Pretty flimsy really.
I wanted to be able to move it in at least two axes so I redesigned it so that the mirror centre can be moved vertically to account for tubes of different diameters. I also want to be able to swivel the mirror around it's vertical axis. With regard to the vertical adjustment, my tube is roughly 50mm diameter but it is fairly old and if I have to replace it I have noticed that new 40W tubes are 55mm diameter. This will raise the centre height by 2.5mm so I want to be able to keep the beam in the centre of the mirror without a lot of rebuilding.
Before I manufactured the new mirror mount I modelled the design using my 3D CAD programme so that I could put the mirror surface directly over the centre of the pivot point. To adjust the 45 degree angle of the mirror surface it is just a matter of loosening the grub screw in the base and swivelling the mirror until it lines up with the second mirror. I don't yet have my tube firing so I mounted the red aiming laser into the tube mounts so that I can get everything aligned without fear of burning or electrocuting myself. The red aiming laser is fitted temporarily into the end of a piece of 12mm diameter steel rod which is in turn held in the tube mounts using two 3D printed "wheels" with an outside diameter the same as my tube. The tube mounts are also 3D printed ABS. They have slotted mounting holes so the tube can be accurately aligned with the chassis.
- Here is the detail of the 3D printed laser tube mount.
- Laser tube mount.jpg (63.99 KiB) Viewed 1865 times
This idea is not original. I came across it on a blog by Daniel Bauen - link is here
http://danielbauen.com/make/index.php/l ... g-bracket/ He deserves full credit for the concept. I just tweaked it to suit my situation.
- Here is the setup for aiming the mirrors.
The first mirror mount is fully machined from aluminium stock and will eventually be powder coated in wrinkle black. I will post some more pictures when I have it installed.
- Here is the CAD model of the first mirror mount.