[Retroplayer]

I picked one of these up last month from a US distributor on Ebay when the seller dropped the price to $400 shipped. I read a ton of reviews before buying it, so I was aware that it was not the best thing out there. But at $400, I could barely buy a tube and supply for that. So, I bit the bullet and bought it with the intention of modding it right off the bat.

I am too lazy (busy?) to do up a proper blog, and it seems quite a few people here have this cutter, so if nobody minds, I will detail my upgrades here.

First off, I gutted the entire thing. The only thing I left still attached was the high voltage wire between the tube and the supply since I didn't want to risk breaking this tiny wire trying to remove the tube and silicone and desoldering. When I say gutted, I literally mean every piece of hardware except those two items was removed right down to the crappy stripped screws (they used countersunk screws on non-countersunk holes!) I then set about with a plan.


Also while I have the parts out, I am generating CAD models of all of the mechanical parts in order to 3D print replacement parts if ever needed and also for the purposes of modding any of those parts if I want.

I have broken the system down as such:

1. Electrical
2. Safety
3. Air system
4. Cooling system
5. Exhaust system
6. Mechanical
7. Electronics
8. Aesthetics
9. Laser/optics/alignment

These won't be covered in any particular order except the order in which I perform the mods. And some of the systems are intertwined, so there may be some repeating of information.

Laser/Optics/Alignment:

I started with the laser bay area since I didn't want the tube dangling loose for very long. I removed the tube and cleaned it, then wrapped it in a towel and taped it up and set it on top of the cabinet while I worked.

Inside the laser bay area, I removed the crappy collapsed water tubing they sent with it. I installed latex tubing instead and carefully zip-tied it to the laser tube. Some soapy water helps slip the tubing on very easily.

I had read a bit and decided it made sense to input the water at the front of the laser and out of the back which is the opposite of how it was labeled originally. I installed check valves on the latex lines near the laser tube nipples. The purpose is to keep water filled in the tube with some pressure to prevent air bubbles from forming due to a cavitating pump or unlevel surface. It will also help a bit when working on the cooling system to prevent water from running all over.

It may mean using a more powerful pump if there is some restriction in the flow due to these check valves, but the benefit of having them outweighs that IMO.

Attachment 262876

I then used foam cable-clips to secure the water hoses and to add some strain relief to prevent pinching in the lines. I picked these up in the home theater section of Home Depot.

I added rubber grommets to all the holes in which wires would be routed to prevent wire chaffing from rubbing on the metal edges. I placed a piece of high-density foam in the back wall of the laser bay to protect the laser if moving it around jars the tube around a bit. Also because I slid the laser all the way back to get some more room in the front for eventually adding a red alignment laser (still not enough room!) I didn't want the glass tube sitting up against the metal where it could get banged accidentally.

Attachment 262878

I removed the hard rubber spacers that were put under the laser in the holder brackets and replaced them with neoprene strips cut from a mouse pad. I placed these on the top and bottom. This also provides a bit of a spring to adjust the laser up and down without putting too much pressure on the glass tube.

I also removed the over-sized bolts holding the brackets in place and replaced them with M5 bolts with a flat washer and locking washer. This actually allows you to slide the brackets side to side about 5mm to help center the laser since there are actually slots in the chassis for this purpose. With the over-sized bolts, you couldn't move those brackets.

Then I added a magnetic reed switch to the edge where the lid rests in order to create an interlock. The magnet is mounted on the lid. The switch opens when the lid is open and closes when the lid is closed. Response is very quick. These are meant for an alarm system to sense when doors or windows are opened. They can be picked up from Radioshack.

Attachment 262880

I also noticed a hole in one end of the lid about 4mm in diameter. It was likely meant for some type of solenoid operated pin lock which would lock the lid when the laser is operating. I may add this feature at some point.

Finally, I installed a 1K ohm NTC thermistor to the output end of the tube using electrical tape. Not the fanciest thing and it is being reworked. The purpose of this is to connect this to a simple little circuit that will open a relay if the temperature is equal to or greater than some set point. If the laser is getting too hot, it will be disabled as part of the interlock system.
Attachment 262882

This wrapped up the laser bay section of the mods (for now) except that I ordered new molybdenum mirrors and mirror holders from lightobjects. I have not received them yet, though. The mirrors that came with the unit were the gold surface mirrors. They weren't in terrible condition, but they seemed a little cloudy to me and I wasn't satisfied after cleaning them. I read a lot about the mirrors and lens being crappy in these. So the originals will be stored away as emergency spares.

There is a little bit more going into this section, but will be covered in another sub-system later.


Electrical

I will be running a RAMPS 1.4 based controller. I also planned to add several 12V accessories. So, I ordered up a 500W ATX PC power supply to give me ample 12,5,3.3, etc supplies. This will be modded a bit for this purpose. I haven't finished it yet, so I will be detailing that later.

I decided that I wanted two electric outlets on the back of the machine for the exhaust, air compressors, or whatever. I also wanted them switchable and possibly under control of the RAMPS controller. So I threw together a little junction box with two 10A optically isolated relays and split a duplex outlet on the hot side. I then knocked out a rectangular hole in the back of the chassis using a hand nibbler (I would use a body saw for a hole this big next time!) The end result is two fully grounded outlets switchable with logic level signals.

Attachment 262884Attachment 262886Attachment 262888Attachment 262890

The laser supply is the typical MYJ40 deal which (fortunately) allows PWM power modulation. This will be controlled by the RAMPS controller. I cracked open the supply to check it for bad solder joints as I read several mentions of bad supplies. I noticed there was a header for a 24V fan, but no fan. So, I ordered an 80MM 24V fan and installed it in the top of the power supply using vibration isolation spacers. I don't know how hot the supply normally gets, but it was there, so I may as well add it.

While I had the supply open, I was also looking for a point to tap into the LED that turns on when the laser is on. I found it was just connected directly to the K+ terminal. So, there I have a point for "laser on" indication which you will see in use later. This K+ line is also connected to the switch on the original control panel labeled "TEST" which fires the laser manually. I will be routing this out to a phone jack on the side of the chassis in which a remote switch can be plugged in to assist in aligning the laser.

That's it for the laser supply. I added the fan and buttoned it up as the solder joints looked good. The connectors are well labelled, so I knew where everything needed to connect. I won't be using the 24V portion of this supply, so it will only be operating the laser.

The steppers are being replaced with 12V steppers with a higher holding torque and a 0.9 degree step angle. The RAMPS controller has DRV8825 stepper drivers which are capable of 1/32 microstepping. So, the capable resolution of the steppers will likely exceed the resolution of the laser itself. It should also be much quieter and faster in operation.

Finally, I did grind away the paint from the earth ground terminal, but I am really not sure why this is necessary if you are using a grounded outlet. Anyone care to clue me in? It was just connected to the ground pin on the IEC plug anyway. If I don't need it. I will just do away with it. I am assuming this is a CE/IEC requirement that if something were to short to the chassis, I wouldn't be electrocuted touching the chassis. This could be solved by just attaching the ground to a screw somewhere on the chassis. Why the need to run a wire from that tie point to the ground in the same outlet you have it plugged into (as per the video included)?

Aesthetics

I gutted the control panel and ordered up some nice black acrylic to make a new panel. With the RAMPS controller, I also got the 12864 full graphics smart display with an SD card socket. The SD card is under the display which will be flush with the control panel. You wouldn't be able to get to it without lifting the lid. So, I ordered up an SD card extender to move this to a more convenient spot.

I also ordered a lock-out emergency switch which will cut ALL power to the machine. And also a red illuminated arcade switch which will act as a kill switch for the RAMPS, which just kills the current job. The illumination in the switch will represent when the laser is in operation.

I also have a touchscreen embedded linux system that I may be installing which will add a network server to the cutter as well as some control from pronterface or similar. It won't fit into the control panel with everything else, but it fits nicely above it, so I would need to knock out some more metal in the lid to install it. One idea for this is to have a library of g-code stored on it that can be called up on-demand.

I am installing an USB panel mount extension cord so I can also place the USB port in a convenient spot and don't need to install the RAMPS up against the side of the chassis.

For the build window, I don't know what the seller had inside the laser tube with the water, but when I pulled the tubing out, some of it leaked onto my build window and it etched itself into the plexi! I imagine it must have been antifreeze of some sort. So this will be replaced with some lexan. Nothing too special about that. But I might get all fancy and etch something into it.

Inside the build area, there will be LED strip lights at the front and back to illuminate the workspace along with a switch to turn these off/on.

This is as far as I will take this first post. As you can see above, I have plenty of more work to do so I will take pictures and detail the rest in future posts unless the mods freak out and don't want this posted here.

[Retroplayer]

I forgot to add this little bit:

Attachment 262892

It's just a little saddle to hold a bubble level on the laser tube to help adjust the laser. You would actually place this over the adjusting brackets while making the height adjustments.

You just glue the bubble on and install some felt pads near the ends to keep it in position. This is not meant to always stay on the laser, but one could create new adjustment brackets with these built in.

[buddydog]

Great post Retro. I was going to install a bunch of interlocks but have changed my mind after many hours. I have a door switch installed but not hooked up. It seems no matter where I sit in the room I'm always at eye level with the slit in the door and can see into the machine (You know, like the Mona Lisa). The beam looks at you wherever you are :-) I think I will add an aluminum block to the door bottom to cover that slit. One thing I thought would be neat is an aluminum beam blocker that pops in front of the first mirror when you open the main door. I use chopsticks wedged in the fan slots to "tighten" the fan/case joint so you can't open the tube door anyway. I think someone posted some tube holders on thingiverse.

[Retroplayer]

Great post Retro. I was going to install a bunch of interlocks but have changed my mind after many hours. I have a door switch installed but not hooked up. It seems no matter where I sit in the room I'm always at eye level with the slit in the door and can see into the machine (You know, like the Mona Lisa). The beam looks at you wherever you are :-) I think I will add an aluminum block to the door bottom to cover that slit. One thing I thought would be neat is an aluminum beam blocker that pops in front of the first mirror when you open the main door. I use chopsticks wedged in the fan slots to "tighten" the fan/case joint so you can't open the tube door anyway. I think someone posted some tube holders on thingiverse.

I tried the tube holders on thingiverse. The one for the 50W was way too big. I even redesigned it smaller, but then the top adjustment nut sits right at the lip of of the door hinge and you can't get your fingers in there. They designed this cabinet with very little room around the laser! I did not find one on thingiverse for the K40, do you have a link?

For a beam blocker, you could modify one of those laser point holders that drop down when you open the lid and lift out of the way when you close it. It is meant for aligning the mirrors using a red laser. I printed one up, but haven't tried it out yet. In your case, just put a shutter on the end instead of the laser pointer.

Hopefully I will have some progress today (holiday from work is almost over for me) and have another post or two to show off. I need to start tackling the electronics installation and wiring.

It also looks like my mirrors, lens, holders, and new laser head will be arriving in the mail today. So, I will be getting those installed.

[ELaser]

Acrylic makes a great shield / window, if it gets smoked you got beam reflections, better acrylic than your eyes.... even cheapo 2 mm acrylic will do

[Retroplayer]

Acrylic makes a great shield / window, if it gets smoked you got beam reflections, better acrylic than your eyes.... even cheapo 2 mm acrylic will do

I was thinking that as well. Maybe even a black acrylic shutter. I would think aluminum would shoot the beam back into the laser and be rather destructive. +1 for an acrylic stop.

Speaking of that... I happened unto a bunch of free 12x12 and bigger heavy ceramic tiles while I was in a recycle shop. I had thought about mounting one in the bottom of the laser cutter as a backstop. Not sure it is necessary as I read that beyond the focal length, the power of the laser is very weak. So by the time it reaches the bottom of the chassis (about 100mm from the laser lens) it wouldn't be much of a problem. But then I see videos of cutters with scorch marks in the bottom of their chassis. Any experience there? Would ceramic be a good stopper (and also good at cooling any hot debris that falls onto it)?

[Retroplayer]

BTW, it is way below freezing here so I have been avoiding going out in the garage, but I will try later. I picked up a really nice steel office desk frame at a garage sale a while back. I have modified it to fit exactly under laser cutter bolting right near the edges. This leaves the entire bottom of the laser open. I had thought about mounting the cutter on there and knocking out the bottom out of the build area in order to fit larger materials in there.

[ELaser]

TEM00 and focal length dude........

set your machine to 20 watts and put some bacon in front of the unfocused beam......

[Retroplayer]

TEM00 and focal length dude........
set your machine to 20 watts and put some bacon in front of the unfocused beam......

This is why you never give a laser to a redneck! lol

I was talking about ceramic for a backstop, not using my hand as a backstop. My hands or any other body part (or meat, lol) will NEVER be in the beam of the laser even 20ft away. Even if I believed it would be safe. I am too attached to all my body parts to play with Darwin.

Not a redneck here However I am eternally grateful to them for demonstrating the millions of ways to die or lose limbs. They have provided invaluable data to the world of safety.

[buddydog]

Definitely a red neck here.

Aluminum is usually dull surfaced and I have tried several different pieces and I believe all that's going on is they absorb the heat and it raises their temperature. In order to get any appreciable power back into the laser would require some seriously reflective surface and the some good return alignment of the piece. Stray reflections from a very shiny surface are much more likely and I'm sure at high power very dangerous.

My unit has a lot of burn/scorch marks on the bottom surface but I don't think it's actually broken the paint anywhere let alone the steel. Mostly appears to be deposits of residue from material being cut blown down onto the surface.

If you get a good base to attach to I think you will be wise to cut the bottom out. I have wished for that myself a lot. The laser has to become a permanent part of the underlying structure and I'm not ready for that yet as I am probably going to get a bigger machine anyway. If I get the 65$ head with movable lens I may do that.

Sorry for the bad info on the holder. I just saw those and figured I would get to it "someday". It is tight in the "tube room". I think I hear a little squeal at certain power levels and I figure it's some stray current finding it's way to ground. If I get time I may design one. It just takes so long with the prototyping and testing. By the way- ABS is a pretty good insulator or at least it works well for radio coils. A 3D printed coil form in ABS has a better Q than an 1920's Atwater Kent bakelite coil form. Maybe a function of the 20% infill instead of being solid.

Grounds: You asked before. At first I had my machine a long way from the panel and I would get the occasional tickle after a run. I am used to this somewhat so didn't worry to much about it. Now it's in the room next to the panel and that it has stopped the "tickle". Bottom line is I am planning a separate shallow ground just for the stray buildup. High voltage supplies are a tricky thing. They will build voltage to whatever "pressure" (voltage is pressure) level is needed to find a path to ground. The trick is to make any path to ground higher resistance than the firing voltage of the laser BUT if for any reason the laser doesn't fire, ground is the next best place to fire to OTHERWISE the power supply will fire internally which causes an internal carbon arc or worse yet makes it's way across circuit paths into sensitive solid state circuits helping them to release the magic smoke! A second ground is a good idea since your home ground will probably be a high impedance (long runs, daisy chained,sharp bends, dodgy connections) to fast high voltage spikes.

I'm jealous of you getting new mirror holders. It's very doable with the stock stuff but fiddly! Interested to see how hard to adapt them.

[Retroplayer]

Definitely a red neck here.
If you get a good base to attach to I think you will be wise to cut the bottom out. I have wished for that myself a lot. The laser has to become a permanent part of the underlying structure and I'm not ready for that yet as I am probably going to get a bigger machine anyway. If I get the 65$ head with movable lens I may do that.

Sorry for the bad info on the holder. I just saw those and figured I would get to it "someday". It is tight in the "tube room". I think I hear a little squeal at certain power levels and I figure it's some stray current finding it's way to ground. If I get time I may design one. It just takes so long with the prototyping and testing. By the way- ABS is a pretty good insulator or at least it works well for radio coils. A 3D printed coil form in ABS has a better Q than an 1920's Atwater Kent bakelite coil form. Maybe a function of the 20% infill instead of being solid.

Grounds: You asked before. At first I had my machine a long way from the panel and I would get the occasional tickle after a run. I am used to this somewhat so didn't worry to much about it. Now it's in the room next to the panel and that it has stopped the "tickle". Bottom line is I am planning a separate shallow ground just for the stray buildup. High voltage supplies are a tricky thing. They will build voltage to whatever "pressure" (voltage is pressure) level is needed to find a path to ground. The trick is to make any path to ground higher resistance than the firing voltage of the laser BUT if for any reason the laser doesn't fire, ground is the next best place to fire to OTHERWISE the power supply will fire internally which causes an internal carbon arc or worse yet makes it's way across circuit paths into sensitive solid state circuits helping them to release the magic smoke! A second ground is a good idea since your home ground will probably be a high impedance (long runs, daisy chained,sharp bends, dodgy connections) to fast high voltage spikes.

I'm jealous of you getting new mirror holders. It's very doable with the stock stuff but fiddly! Interested to see how hard to adapt them.

1. I think some bolted together steel square tubing would be more than adequate for a base. That is really all this is except that it is welded stainless steel. It's not super impressive or anything. The laser doesn't way that much. If you bolt it with wing nuts, you can remove the stand pretty easily. For that matter, you could mash something together with some 2x4s and it will be plenty strong. I can lift the whole laser cutter with one arm, in fact, I tossed the whole crate on my shoulder to bring it inside. The crate weighed more than the laser (I still need to come up with something to do with that crate. I am thinking vacuum former!) Anyway, you could throw something together in a weekend I'm sure. I just happened to have bought this desk frame for "something" some day because it was only $5

2. Well, if you end up wanting those holders (I think they look awesome, myself) I did redesign them to fit inside the 40W machine. They just need a little fidgeting which I will get back to someday. I was just spending too much time on them and wanted to move on. They take about 2.5 hours to print each, so making adjustments takes forever.

3. I didn't know that about ABS, actually (and I am an electrical engineer.) I will file that away for later. I actually really suck at analog electronic design, so I cheat a lot there. I am much better with digital and embedded technology.

4. Got it about the grounds. I still think that a tie to the chassis from the ground terminal on the IEC is good enough. I added the rubber grommets (if you live in the US, Harborfreight has a very nice assortment for very cheap) to the the holes with the wires going into the laser bay area. In my experience, the insulation on high voltage cables becomes brittle over time. Those semi-sharp edges on the holes looked like a prime location for breaking and squealing like you noticed. Perhaps I will place a tie point right by this spot. Anyway, there are plenty of cold water pipes running around the basement, so not a huge deal to connect another ground.

5. I should be getting those mirror holders any minute now, so we shall find out. At $35 a piece, I was a little hesitant as well. But figured WTH? I will probably buy them eventually anyway. As far as adapting them... have 3D printer, will travel One of the most useful tools I have in my entire house. It has saved me far more money than it cost me manyfold. Some examples: I have an old house that is a bit crooked, so some of the doors don't quite latch anymore. I got tired of it one day, and designed up my own thicker strike plates. Problem solved. I inherited my Dad's old table saw, but it was missing the safety key and a few pieces of hardware. 20 minutes of design and printing and I had new replacement parts for it. I find myself all the time in the store thinking, "nah, I am not spending $10 for that piece of plastic. I can just print it!" I've used it all over the house and workshop.

[Retroplayer]

BTW, I will probably have another build thread coming here fairly soon. Over Christmas I was telling my brother about the laser cutter and he mentioned that he would love to use it to make airbrush stencils (he does auto body work.) I was telling him this cutter was probably way overkill for that. The stencil material is very thin and about 8"x10" I told him I could probably build him a diode based cutter in an aluminumn briefcase for under $300. So, started another project for me. Waiting on the 2.5W UV laser right now. 3D modeled the parts for the corexy build platform and made everything very lightweight. I will be using 5V geared stepper motors that result in a step angle of about .8 degrees before the micro-stepping and a grbl based controller. I can probably run the entire thing off from a battery pack.

So, a briefcase sized mini laser cutter shall be in the works soon (me and my big mouth!) lol

[Retroplayer]

Lens, mirrors, mirror holders, and new head have arrived. The mirror holders are much larger than I thought they would be. The holes don't quite line up on the existing mounts and with the added size, they couldn't really drop in the same spots anyway. So, some adapting is definitely going to be needed. The mount screws I found fit these well are M4x10mm

In the photos, you can also see my 3D printed lens assembly bracket.

Attachment 263000

[ELaser]

Can't see the photos or anything, and know bugger all about the k40 lasers, but in my limited experience, (seeing a mate do this to his fleabay chinese laser) upgrading the optics as you are doing is probably going to blow you away, and I suspect you will be kicking yourself for not spending that 35 bucks a pop way way sooner... you can use a small self contained laser centre finder jobbie and fire it back UP the Z axis to align everything, tube off, mains unplugged, dimly lit room, technically it is exactly the wrong order to do the optics in, but you seem like a patient and careful chap, so no real bother. Be warned it will diffuse though, those lenses and mirrors aren't quite right for optical.

Lots of the optical laser guys refer to co2 jobs as heat lasers as they are so far in the IR end of the spectrum, they don't consider it to be "light" lol

I know two guys went to the same schools and uni's etc, one now designs vertical slit 1.5 pico lasers for fibre comms, the other designs multi-kilowatt TEA lasers for industry, if you think mac vs pc or ford vs chevy guys can have arguments, you ain't seen nothing...lol

if you got ZnSe kit, please be aware it is as fragile as a biscuit, and extremely toxic to the human body if ingested even in tiny quantities, so do take care.

[Retroplayer]

Can't see the photos or anything, and know bugger all about the k40 lasers, but in my limited experience, (seeing a mate do this to his fleabay chinese laser) upgrading the optics as you are doing is probably going to blow you away, and I suspect you will be kicking yourself for not spending that 35 bucks a pop way way sooner... you can use a small self contained laser centre finder jobbie and fire it back UP the Z axis to align everything, tube off, mains unplugged, dimly lit room, technically it is exactly the wrong order to do the optics in, but you seem like a patient and careful chap, so no real bother. Be warned it will diffuse though, those lenses and mirrors aren't quite right for optical.

Lots of the optical laser guys refer to co2 jobs as heat lasers as they are so far in the IR end of the spectrum, they don't consider it to be "light" lol

I know two guys went to the same schools and uni's etc, one now designs vertical slit 1.5 pico lasers for fibre comms, the other designs multi-kilowatt TEA lasers for industry, if you think mac vs pc or ford vs chevy guys can have arguments, you ain't seen nothing...lol

if you got ZnSe kit, please be aware it is as fragile as a biscuit, and extremely toxic to the human body if ingested even in tiny quantities, so do take care.

Well, given that I have not used the laser even once yet, I probably won't kick myself too hard. I had read what a great improvement it was. It was in the plan from the beginning. The mirrors are 20mm molybdenum. I got a 3 pack from ebay for $35. The focal lens is an ZnSe 18mm 38.1 focal length. The lens was $52, I think. I couldn't find anything about possible lens options for the CO2, so I went with what people seem to have. No other type for CO2 was listed at lightobject. What else is there? I could have used the mirrors in the original holders and if I fail to figure out a good way to mount the new holders, I may have to do that. The holders themselves were $34.50 a piece. The laser head was only $16.50

I also ordered (wrongly) a huge beam combiner for $75 on ebay. 1 1/2 inches in diameter and 3mm thick! Way too big to use. I will probably sell that. I ordered a 20mm one for only $18 from China. I'll see that in February, I'm sure. lol

And as for the alignment suggestion... head-smack. Why didn't I think of that? Geez. So simple. I would remove the focal lens to do it, of course. Then it is all mirrors. Thank you so much for that suggestion!

No idea why the pictures are suddenly not showing up in-line. They appear as links on my end, too. If you click on them you can see them.

EDIT: I think I fixed the pictures

[buddydog]

Retro the point about the case whatever you use is it can't be moved around at all. Even small movements will effect alignment. I mistakenly have mine mounted on a wheeled cart and I have to lock it all down before alignment and any movement after changes it.

This is one of the best and most helpful videos I found on these machines:
https://www.youtube.com/watch?v=KhhOHUe_b6o
mirror alignment is around 10minutes.

[Retroplayer]

Retro the point about the case whatever you use is it can't be moved around at all. Even small movements will effect alignment. I mistakenly have mine mounted on a wheeled cart and I have to lock it all down before alignment and any movement after changes it.

Hmm. What do you think is the mechanism for misalignment just from moving it? The mirrors and tube should be locked down fairly well. They do use crappy screws (I intended to replace every single screw in this thing) and no lock washers to be found. Perhaps you need to replace some of those screws, add some lock washers, locking nuts, and maybe even some loctite.

There should be no reason for the alignment to go out of whack unless it is subjected to some serious impact. Of course, it could also be due to the crappy mirror mounts. I have seen a mod (don't remember where) to improve on the stock holders. I recall the person stating that they tend to get out of alignment.

I made up a design of a working bracket for the first mirror using the new holders. The problem is that there is so little room in the laser bay that I won't be able to get my fingers in there to adjust it. The bolt heads are square, so I might be able to get a wrench down in there and if they are "professional" like they say they are, I shouldn't need to adjust them often. I spent quite a bit of time re-designing and printing trying to gain some room for the fingers, but it just isn't going to happen. If all else fails, the mirrors will fit in the original holders and I could focus on improving those (or maybe even 3D print a smaller version of the pro mounts!) But that's $35 not being used.

For the second mirror, I think I can just reuse the existing bracket and just drill some new holes. Plenty of room for the fingers there. The main difference is the height of center. In the laser bay area, the holder sits on a bracket, so I needed to design something shorter to put the center of the mirror about 40mm from the bottom. It ended up being 12mm in bracket height.

Here's what it ended up looking like:



The mirror mounts diagonally at 45 degrees of course. The bracket can slide side to side and the mirror can slide front to back which results in some course adjustment of the beam side to side. I had considered a design where one bolt was fixed and the other was positioned in an arc slot to course adjust the actual angle of the mirror. I didn't think it was necessary though. It should be 45 degrees to the laser, right?

[buddydog]

I'm pretty fussy when aligning and the problem is the case. It's strongly built but could use more. The beam path is actually pretty long when it's at it's farthest xy position. I have the same problem even with a 1200# metal lathe and even with that I use thin shims to get everything right. I didn't explain that it's not the mirror mounts themselves, they are hard to use but once set don't change, it's the case moving slightly changing the beam path. Nothing happens after alignment if the case is setting on a good base and you don't move it. By the way I am not dissing the case. I think you would have to add 2-300 pounds to get it to be bullet proof. I have noticed holding alignment appears to be one of the problems folks encounter when building an open frame diy machine.

Edit I read my last over and I still didn't say it right. I'll try this: If you had perfect alignment and the placed a 1/16 inch shim under one corner, alignment would change. If you then removed the shim it would return to perfect again. The case will "tweak" ever so slightly. You can't see it but the beam will change over the optic path slightly. By the way it will still work but you will not get the performance these low power machines can deliver unless everything about the optic path is perfect. I think this may be the reason some folks claim these can't do anything. It's amazing what they can do when set up correctly. The one part of the optic system you can not setup right stock is the head 45* mirror since it's not adjustable on the stock machine.

[Retroplayer]

Edit I read my last over and I still didn't say it right. I'll try this: If you had perfect alignment and the placed a 1/16 inch shim under one corner, alignment would change. If you then removed the shim it would return to perfect again. The case will "tweak" ever so slightly. You can't see it but the beam will change over the optic path slightly. By the way it will still work but you will not get the performance these low power machines can deliver unless everything about the optic path is perfect. I think this may be the reason some folks claim these can't do anything. It's amazing what they can do when set up correctly. The one part of the optic system you can not setup right stock is the head 45* mirror since it's not adjustable on the stock machine.

Oh yeah, that makes perfect sense. I have noticed that my case has been wobbling lately. That should be fixed, I think, once I bolt it to the desk frame which will twist it back straight. Sounds like I should do that before aligning the lasers then.

In what way would you adjust the periscope mirror on the head if you could? I am imagine it is fixed because it should be exactly 45 degrees to the lens. Has this been a problem for you? I don't even think you can adjust that final mirror on the pro head.

[buddydog]

Oh yeah, that makes perfect sense. I have noticed that my case has been wobbling lately. That should be fixed, I think, once I bolt it to the desk frame which will twist it back straight. Sounds like I should do that before aligning the lasers then.

In what way would you adjust the periscope mirror on the head if you could? I am imagine it is fixed because it should be exactly 45 degrees to the lens. Has this been a problem for you? I don't even think you can adjust that final mirror on the pro head.

Yes it was a problem for me. I put some paper shims under one side and got it closer. Shimming is difficult and puts uneven pressure in the edge of the mirror. When your all done with the x y alignment, remove the lens and stick a sticky note to the bottom of the head. Use your finger to "iron" in an impression of the hole on the bottom of the head. Now test fire a shot. If things are good your paper will have a hole in the middle of the "ironed" in circle. Assuming the lens is centered and symmetrical (a lot of assuming by the way), you should have the best power you can from that lens (yes you have to set the focal point of course). Even if your hole is a perfect 45 on the down mirror, what about a mirror out of tolerance? A bent head mount? And so on. By the way it may be possible to make some adjustment with the other mirrors but that just adds to the alignment difficulty.
I am sorry to hear the expensive head may not have the adjustment. I want the 45 down adjustment in a head along with an accurate up and down adjustment for the lens so I can cut the bottom out of the laser and cut acrylic and plywood. I may have to fire up the lathe and mill and roll my own.
I'm going to get my Z table mod on tonight or tomorrow. I am finally happy with it but the installation requires a gear head so I'm going to have to drive customers away that are not qualified to do an accurate drilling job.