A quick five-minute hack to use the external ammeter while retaining PC control of power settings

This article is for the Cloudray M100 Laser Power Supply, but it should apply across the entire M-series of Cloudray Supplies. Full Disclosure: This is an affiliate link. Even if you never intend to order a massive CO₂ laser, just clicking that link will still help us stay afloat – Thanks!

The power-supply comes with this sweet display screen, letting you know exactly how much power you’re actually running! Not necessary, but cool. The problem is that when this is plugged in, the knob on the left side will override the power-setting that your laser control software (lightburn, etc) is sending. Cloudray claims they have a switch on the PSU itself to disable this, but our supply shipped without said switch.

Luckily, this is easily remedied with a pair of diagonal-cutters and a tiny screwdriver!

• Remove the knob itself by pulling straight off
• Insert the screwdriver to remove the back panel
• Remove the PCB/Screen assembly from the housing
  • Gently push on the screen
  • Pry the retaining tab back just far enough for the pcb/screen assembly to move slightly
  • Repeat this for each retaining tab, working around the screen multiple times
  • Once both the PCB and then the Screen have passed the tabs, the assembly will slide free
• Using your diagonal cutters, snip the center tab of the potentiometer
  • You can also desolder the entire potentiometer from the PCB if desired
• Use the screwdriver to bend these tabs for additional clearance
• Reassemble by gently sliding the pcb/screen back into the housing, and pop in the back plate
  • Make sure the PCB slides past the retaining tabs
• Done!
  
  

And of course, we have pictures for all of this:

Bonus: How did we figure this out? / Why does this work?

We knew there were only two options for the layout of this control board. Either:

• 1) There is a custom microcontroller on this control board
• 2) This board has only an off-the-shelf display driver, and passes the other signals through

First, we checked the IC on the board…. if we could look up a part number that would be a giveaway – however, it was completely blanked out. So we investigated, trying to figure out where the signal from the potentiometer (signal is always the middle pin, with V+ and GND on the two sides) was connected to. Probing with a multimeter, we found a direct connection (0.2Ω – close enough!) between the center pin and pin 4 on the RJ45 jack! This points to the pass-through option, so we snipped it – worst case, we’d have to solder it back. We put it all back together and…. we were right!

Welcome to our infodump on doubling the power of your laser cutter! We’ve got a RedSail, but this should apply to the entire genre, so lets jump in!

First of all, links:
Laser: https://amzn.to/4jb3jAE
Power supply: https://amzn.to/3E6LaVD
Chiller: https://amzn.to/3FXQJ9r
Mirrors: https://amzn.to/4cnvjhT
Cheaper lasers I used for a totally unrelated project which are still badass: https://amzn.to/44f9X4f

Full disclosure: Those are all affiliate links. PLEASE click one. It doesn’t matter how many, doesn’t matter which one, doesn’t even matter if you order: if you ever use amazon it will help us keep gliding just above bankruptcy. That said, we did a extensive research before ordering and have been happy with each of the products listed.

Due to a series of unfortunate events (our water pump got unplugged), our laser tube died. It had been slowly aging, becoming less and less powerful over the years, and this provided an excellent excuse for more Speeeeed and POWAH! You see what I did there? You thought it was a meme but we desperately need that 0.5% commission. If you already clicked above… I’m sorry.

Shameless monetization aside, we had a few options, but beyond 100w those options are exponentially more expensive. We decided the sweet spot was right at ~95w, which meant a tube about 8″ longer than our laser cutter… We paired that with an 80w power supply – typically laser tubes perform equally well at 80% and max power, so this should result in a much longer life, especially with the new chiller.

First step, as always, measure everything. We grabbed dimensions off the existing laser cabinet, the chiller, and some random caster wheels that we found in the shop. Next, we threw all of that into CAD to mock up a frame.

A frame isn’t technically necessary, but this will live in a communal shop, and things get bumped – so we wanted to make sure our investment was protected.

Based on this frame, we then calculated the side-panel we needed. This was where the ShopBot came in clutch. We CNC’d the side panel – giving us the exact template needed for welding! So we cut angle-iron to size, clamped it all to the side-panel, and welded up two of them. Our chiller was 12″ thick, so we added some 14″ spacers, and then spraybombed the entire thing.

As some of us worked on the frame-extension, another team focused on the laser itself. We started by printing adjustable tube mounts. And then we modified the file, as attached here: LT2H.FCStd <True hacker skills, changing extensions to bypass automated filters>

With these mounts installed into the laser, we then built a shoddy mock-up of the laser tube so we could mark the new centerline… and with that, it was time to fully commit, and cut out the side of the laser enclosure. We drilled the center, used a compass to scribe a circle much larger than the tube itself, and then used a jigsaw to make the opening, before lining it with some slit rubber hose. We really really don’t want to break the tube against this sharp edge.

The last step before installing the tube was to build a sub-enclosure for the tube itself, to make sure none of the electrons (at 28kv!) or photons (at 80w!) escaped – while including access so we could actually get the tube into the enclosure. While we were at it, one of our members wanted practice building drawers, and knocked out a cute little drawer in the front, just the right size for some 1-2-3 blocks or calipers (the battery never dies!)

With that it was time to wire and plumb the tube! Both are pretty easy, the power supply had the exact same pins are our previous supply, and there are only two connections from there to the laser. For the Chiller, we wired the kill-switch to our laser’s kill-switch input – they both came with XLR plugs, and a straight pass-through was all they needed. Plumbing is equally simple, tubes from the chiller go to both ends of the tube, the chiller gets filled with distilled water, and is turned on – then we grabbed an automotive jack to tilt the entire laser and chase out the last bubble of air in the system.

The last step was also the most tedious: Alignment! First, we had to move the primary mirror forward 15mm (40mm of new tube radius – 25mm of previous tube radius), which was a quick drill+tap job. [Oh! One final link in case you haven’t clicked any of them yet (please do) – this was $12 and I love it.] Then, using small squares of paper taped in front of the mirrors (don’t tape straight to the mirrors, it can cook them), we adjusted the wheels on the laser mount until we were square, and hitting the center of the lens. – just a quick blip of the laser at 10% power will leave a burn mark on the paper to work from. Then, a bit of isopropyl on a q-tip to clean that lens, and move on to the next one! We adjusted the previous lens with minute twists of the set-screws in the back, taking a test shot at both extremes of travel, until we ended up with both locations hitting in the same place. Rinse and repeat for the final mirror, and we’re done! We hooked in the exhaust-fan and it was time to cut!

Get it? On the ShopBot? Because…  I know, it’s a terrible pun, but I actually did most of the work with the ShopBot too!  This post is designed to show off what you can do with the tools in our shop – we offer free training for everything shown in this post, and it’s easier than I thought!

   The story starts when my friend made fun of my entry-way table, which is always covered in stuff. I realized I need an entryway cabinet, so I could hide all of that stuff in drawers! So I was bouncing ideas around in my head when a friend offered me a slab from his old tree.  Cheap, cut with an Alaskan mill (aka a chainsaw with a spacer rig), and aged a few years in his back yard.  I’ve watched fancy furniture videos on the internet for years, and here was my chance to try it!

 

 

 

The first challenge is turning this chunk of tree into “Lumber”.  The professionals have giant planers… ours is only 12″, and too small for this slab.  But what we do have is a ShopBot! I drilled a few recesses and screwed the plank to the table, and ran a decking pass. Just a giant rectangle with a wide bit…  and then hand-drove the head around to do cleanup on the edges just outside the rectangle.  One side done, I flipped the slab, re-zero’d the Z axis, and in just under an hour I had a perfectly flat and parallel piece of lumber!  While it was screwed down, I used the CNC to cut it to size. Using the same large rectangle, I rounded the corners, let it overhand the slab on one edge (to get a live-edge look), and cut only the perimeter this time.  I took it down to 1/4″ of material remaining – this meant I didn’t have to worry about the slab moving because I’d cut it free of the screws. For the remaining 1/4″ I used a jigsaw for a rough first pass – staying wide of the edge – and then used a follower bit in the router to match that edge with the CNC’d profile.

The next step was sanding. So much sanding. I think I did 80-120-200. I don’t know if that’s right, I know I should have gone higher, but after so much sanding I didn’t care anymore. While sanding,  I’d take breaks to work on the live-edge. I had to pull off the bark and spongy sap-wood so I only had good material left.  I mostly worked with chisels.  If you’re at our hackerspace ask around and borrow someone’s nice chisels, the communal chisels are thoroughly abused. Despite not knowing what I was doing, I slowly got down to good wood, and the slab was ready for finishing!

Before finish, I moved onto the cabinet itself.  While working on the slab, I’d been working on the CAD for the main body. This first-round of CAD was only to figure out the proportions and the look of the piece. I can’t draw, so in order to figure out what proportions looked right, I had to model it. The first models were ugly. If you wanted to be charitable you could call them “highly functional.”   My modeling process is to make a round of updates to the CAD, and then send a screenshot to a friend asking what’s wrong with it.  Then another round of updates to fix those issues, another screenshot, and ask a different friend what’s wrong with it. It’s the same way I revise my high-effort videos (please sub!).  In addition to purely-aesthetic changes, the cad evolved as the slab shrank down to final dimensions.

 

With the cad almost-finalized I had a few structural pieces to cut on the shopbot. The legs were nice and simple, and cut out of some scrap 2x8s.  Less simple were the front corners, which I had decided should be rounded. It definitely looks cool, but unlike the previous cabinet, this curve was too tight to be able to steam-bend, while far too large for a chamfer bit.  Luckily, we have a shopbot! I exported a STL of the part, loaded it into aspire, and set up a 3d toolpath. Key tips: Use a round-nosed bit, I used 1/2″.  Take aggressive steps on the roughing passes, but dial it back to baby steps for the finishing pass. I routed this out of a 6×6 from homedepot, and while the finishing pass did take an hour, the results were worth it. A bit of sanding, and I had a long stock of quarter-round I could use for the edge rails.

With these corners and the table-top, I could trace out the base of the cabinet, which I bulked out on the table-saw and finished with a jigsaw. Having both the base and the corners gave me a final dimension for the face of the cabinet – it’s always best to measure these and not rely on the cad. I cut the doors first. A coat of stain, and then a light engraving pass to through the stain to expose a pattern! I fell down a rabbithole on the door design, which you can read all about in the previous post here.  Doors done, it was time for the fascia / drawer covers. I left tabs on these pieces, locking them all in place so that I could use the vacuum hold-down.  Then I repeated the stain-and-engrave trick to decorate the drawers.

For the drawers, I knew I wanted a similar mathematic exponential design… I tried circles again, but it looked off. Instead I just pulled up a graphing calculator and started playing with equations…  I knew I wanted curves, so that meant a sine wave. I knew I wanted it to expand over time, so that meant an x*sin(x) curve. Plotting it, I realized it needed to slow down over time as well, so x*sin( ln(x) )…    After a bunch of guess-and-check to tweak the curves, I got this:

I could pretend I then used these equations in Solidworks to programmatically generate my cut-path, but I didn’t. I hit print-screen, cropped the curves in gimp, and traced them in Inkscape.  Once there, I could stretch it to fit my drawer fronts, and engrave more math into my nerdy furniture.

From here, it gets pretty boring. I bashed a frame out of 2×3 and 2x4s, sheeted it with plywood, installed home-depot hinges, and built drawer-boxes. Which, of course, I could have done on the shopbot! Instead I locked my slide and bulked them out on the table-saw. If you really need the details LMK in the comments and I’ll write a “Drawers 101” course. I spec’ed out some nice push-to-open drawer-slides on Woodcraft, but their website crashed so I bought knockoffs on amazon. I mounted them on random scraps of wood that would give me the right offset…. which is definitely not the right way to do it, but it’s hidden so it’s not getting fixed unless it breaks.

The last step is the surface-finish.  I started with the body: Another round of sanding, and then to the tricky part: Matching stains. The different woods reacted differently to the stains, so I had to whip up a custom mix of stain using SpunSpoon. I put together a short video explaining this process:

Was that really just a commercial for SpunSpoon? Of course it was. Do you need a SpunSpoon? Of course not. But it did work a treat. Then excessive coats of poly and call it a day.

The slab is the start of the show and would see more abuse, so it deserved and needed more thorough finishing.  First were two final rounds of sanding, and I popped the grain between grits by wiping it with a damp cloth.  Then came a dark stain, and once that dried I did touch-ups with a sharpie – darkening the various worm-holes and scars that stood out against the now-dark wood. It’s super fast and simple, but this quick step makes a huge difference in appearance.  After that, I clear-coated the entire slab with poly. Poly is never a mistake. After the poly I mixed up a bunch of deep-pour slow-setting self-leveling epoxy, and smeared a layer of this over the entire table.  It looked amazing, but it also leaked through every minor crack or worm-hole on the entire table.  Because of this, my planned two coats turned into 4 coats, all 12 hours apart. Next time, I’m going to superglue, hotglue, or epoxy every single defect before the pour. Epoxy done, I tented the board in some cheap plastic sheeting to protect it from sawdust, and let the whole thing cure for 4 days. Finally, I shaved the epoxy stalactites off bottom, taking shallow passes with an inverted chisel until they were flush.

And now, almost a month later, we can move this cabinet off the shopbot!