Hi Russ, I can't really comment on rubber stamps, though that was what these machines were intended for. The only rubber I got was a sample of the professional stuff and it wasn't pleasant working. My friend has a 120w laser cutter and uses that for occasional stamps, this stuff chars quickly and produces loads of white soot. I think with softer rubber you might get good results, I add a sample of the cut I could produce without going so slow as to char the rubber. The etch isn't very deep (or reversed for stamping)
I would say the number one upgrade is probably the air assist, this is the difference between clean cuts and possible fire inside the laser cabinet. The air blows the smoke and flame away, it also keeps spatter and soot off the focusing lens. On larger machines the air assist uses quite a high volume of air, but here we can get away with a small nozzle and low volume air supply. I use an aquarium air pump, very low power but sufficient for this machine. Next up I would say the water cooling, this is important, you don't want the cooling to fail or start growing into some primordial soup. I use a 30ltr barrel, with 20ltr of distilled water and a litre of RV coolant, this acts as antifreeze and anti fungal. The water should be good for a couple of years or so, before needing replacement. To monitor the cooling I added a flow gauge and temperature sensor on the output of the laser tube. The laser starts to tail off in power as you go over 22-25℃
Another addition is a honeycomb bed, chuck out the suppled sheet metal affair designed for stamp making
It just gets in the way for everything else. I messed about finding the optimum hight for the bed, and then laser cut some side frames, stuck them on with double sided tape. During this I found the internal fume extraction duct protruded too far into the cavity and would foul the bed, so I pulled it out, cut it shorter.
When/if you buy one of these, strip down the optical mounts and clean everything. The supplied mirrors were a bit dirty when it arrived, but that was nothing to what happened later as I cleaned the mirrors. All the cutting fluid was still on the mirror mounts and the IPA I used fogged the mirror with cutting fluid. I didn't notice and it gradually baked on and robbed the laser of power. Fortunately new mirrors are pretty cheap and I replaced them. Other minor mods included adding internal LED strip light as visibility can be bad especially if the cabinet gets smoky. For control you don't need much in the way of a PC, I use an old Asus Netbook and run K40 Whisperer, which is free software. Basic, but does the job, you can use Inkscape to generate the vector files, be that SVG or DXF.
One issue we did note, some months after the machine was in use laser power suddenly started to drop. I had kept a record of my materials, power settings and feed rates. These all changed, not sure if it was just the power supply or tube settling down, but things have remained constant now, so it's a good idea to keep a notebook of settings. Early on I added the power settings on the control knob with a Sharpie. 12ma is my do not exceed point, it's the trade off for a longer tube life.
