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View Full Version : Crazy Plans for my K40 Chinese laser



Joe Walmer
10-24-2015, 10:34 PM
I bought a k40 off ebay to take the tube and psu and try to make it work on my GCC mercury laser as the RF tube needs refilled. I got it new in 2003 and it worked for about 10 years till it was low. It still cuts only at about 30% power. As soon a I know that project works I will have a k40 body I can gut and make into a real laser.

I have some parts from the openbuilds part store V wheels, v rails, and open rail converters so I plan on remaking the entire xy system from scratch. I will take out the entire xy system and sell it on ebay along with the moshidraw controller. I will replace that with my smoothieboard controller I already bought. It will be strictly a cutting machine as all I do is cut 3mm acrylic. So a flatbed machine is actually ideal for me, I don't need a z table at all.

With that said I plan on doing a few things different than any other k40 upgrade I have found yet. First off I will take out the middle divider that separates the 2 compartments. This should give me a lot more room and let me have something like a 24"x14" This will allow me to make 4 of the products i make all in one go with room to spare vs not even one of the products with the original 200x300. I will mount most of the electronics outside the case and slowly put them back in one at a time where they fit and don't interfere.

I see how much room there is from the bottom of the laser to the laser level and its a lot. I may actually take the lasertube and mount it directly below where it is at now inside the cutting area of the machine. This would let me build the xy rails from 20x20 openrail and have the honeycomb table right above that so the piece you cut will be 40mm from the bottom of the machine maybe 60mm actually with the y rail in place. This makes more sense when you see my original train of thought that brought me to this other than trying to figure out how to raise the whole xy system. This will also allow me to put all the electronics where the laser tube is now letting me have the entire 800mm width of the machine for a cutting area!

I plan on putting in 2 laser tubes. Even if I have to cut out the floor to the laser tube chamber (not the floor to the machine) and raise the first one up a bit (which I don't think I will have to do). Why 2 tubes? for me it makes sense as I cut things in pairs and they are always spaced the same distance apart. So how does this thing work?

Basically I have 2 identical laser heads. The first is the Master head its the same head the laser came with then the slave head is spaced 6 inches down and it has the mirror raised up like a periscope 40mm or whatever it is to catch the second laser beam. Basically making it a ganged laser and ensuring the 2 matched pieces are exactly the same. This is how they cut parts for aircraft carriers so they are the same. I can use a Destaco toggle clamp or just use my Epilog laser to cut different length connectors that lock the heads an exact distance apart.

So sound pretty crazy or what? Ill just keep buying k40 lasers to steal the tubes from and work on the next chassis. In the end I will probably settle for a 18x12 setup and use the rest of the space to fit everything into the machine. Things like the water cooling radiator I plan on putting in the front of the machine and that is where the air intake will come from. Ill get a tube reservoir and mount it to the outside of the machine for looks and to save space and I already have a mini pump a clone of a mcp50 its very small and could be mounted anywhere. I plan on putting my exhaust in the bottom of the laser so it pulls it right from under the vector table.

I also have a few watercooling blocks for old cpu's way back on Pentium 4 times and I plan on putting it on the bottom of the smoothieboard controller to cool the stepper drivers so they cant overheat.

I have looked and looked and haven't found anyone that repaced the xy rail system in one of these If anyone knows of any I would love a link.

Dan Hintz
10-25-2015, 7:17 PM
Most of the major laser manufacturers have a similar arrangement with two focusing lenses set apart by a specific distance but running on the same track. Some use two tubes, some split the beam power via optics. The major downside is you need to tune two different tubes to output the same power, as well as make sure both substrates will react to the power in exactly the same way. I rarely get substrates that act in the manner, so you end up overpowering some just to keep the settings the same from job to job.

Bill George
10-26-2015, 7:15 AM
Joe, It sounds like you are retired and have a lot of time for projects. Evergreen could recharge your tube for about $800, and in the long run that would be cheaper.

Joe Walmer
10-26-2015, 10:16 AM
Well George here is my logic for it all. Everyones GCC laser control board goes bad sooner or later mine is like 12 years old since i bought the laser. They cost 1500$ of you can find one and i had a guy wanting to but mine not too long ago.

So if I get my laser tube refilled and i think i would go with photovac to do it it. So I can run this until it dies then I have to gut the insides of the GCC machine and new motion controller etc.

So if this works I will use the GCC laser till the motherboard dies or until I have another laser built to replace it hence the k40 stuff. Once I have another backup laser I can sell the laser tube I have that needs recharged for 1200 -1800 as i saw on ebay and then sell the control board for 1500 then i have the machine to rebuild another laser. So I could theoretically sell the mobo and laser tube from my machine and get 3,000$ with that I could build like 5-6 more lasers that do what I need and if I doulbe up the laser tubes on a few even less than that. The servo motors may be a pain but I think I can get em to work fine with 2 gecko drivers. Either way I am excited about building lasers always have been and now with the whole 3d printer explosion its the best time to do it.

Not to mention I am tired of RF tubes as all i do is cut material and I will get more power for the cheap. The 12 year run for this tube is probably the exception not the rule as my epilog laser we got 5 years after this one has had the tube replaced 4 times now. not to mention the control board 3-4 times. the last 2 times fell withing each others 2 year warranty and we had them replaced for free. ROCK solid service from epilog although it seems the tubes longevity is not as tough.

All I do is cut 3mm acrylic Dan so I don't think it will be too hard getting the beams in that range.

Joe Walmer
10-26-2015, 10:49 AM
I think this is just a move really to get us a laser up and going at the second shop until I can build the 3rd one and then resell the synrad tube and control board for the GCC. I know a few people with bad motherboards and one just got a fresh tube a week earlier.

I can sell off the parts then for about 3,000 and keep the laser frame, optics, etc. in place to build a new one probably a DSP controller upgrade.

If I had to do it I would replace the xy besides the bottom 2 rails and try to save the 2:1 pulleys in there. My reason being is the wheels to replace them is big big bucks when I could just build a new carriage with delrin v slot wheels etc that cost 2-3 bucks each.

I would then put the 40 watt laser back in the k40 and by then have it all upgraded hopefully and but a 60 watt for the gcc.

Gary Hair
10-26-2015, 10:58 AM
Well George here is my logic for it all. Everyones GCC laser control board goes bad sooner or later mine is like 12 years old since i bought the laser. They cost 1500$ of you can find one and i had a guy wanting to but mine not too long ago.

So if I get my laser tube refilled and i think i would go with photovac to do it it. So I can run this until it dies then I have to gut the insides of the GCC machine and new motion controller etc.

So if this works I will use the GCC laser till the motherboard dies or until I have another laser built to replace it hence the k40 stuff. Once I have another backup laser I can sell the laser tube I have that needs recharged for 1200 -1800 as i saw on ebay and then sell the control board for 1500 then i have the machine to rebuild another laser. So I could theoretically sell the mobo and laser tube from my machine and get 3,000$ with that I could build like 5-6 more lasers that do what I need and if I doulbe up the laser tubes on a few even less than that. The servo motors may be a pain but I think I can get em to work fine with 2 gecko drivers. Either way I am excited about building lasers always have been and now with the whole 3d printer explosion its the best time to do it.

Not to mention I am tired of RF tubes as all i do is cut material and I will get more power for the cheap. The 12 year run for this tube is probably the exception not the rule as my epilog laser we got 5 years after this one has had the tube replaced 4 times now. not to mention the control board 3-4 times. the last 2 times fell withing each others 2 year warranty and we had them replaced for free. ROCK solid service from epilog although it seems the tubes longevity is not as tough.

All I do is cut 3mm acrylic Dan so I don't think it will be too hard getting the beams in that range.

I think this is just a move really to get us a laser up and going at the second shop until I can build the 3rd one and then resell the synrad tube and control board for the GCC. I know a few people with bad motherboards and one just got a fresh tube a week earlier.

I can sell off the parts then for about 3,000 and keep the laser frame, optics, etc. in place to build a new one probably a DSP controller upgrade.

If I had to do it I would replace the xy besides the bottom 2 rails and try to save the 2:1 pulleys in there. My reason being is the wheels to replace them is big big bucks when I could just build a new carriage with delrin v slot wheels etc that cost 2-3 bucks each.

I would then put the 40 watt laser back in the k40 and by then have it all upgraded hopefully and but a 60 watt for the gcc.

I think I've gone cross-eyed...

Joe Walmer
10-26-2015, 2:31 PM
I think I've gone cross-eyed...

Since the thread is called Crazy Plans ill take that as a compliment.

Lee DeRaud
10-26-2015, 2:45 PM
Since the thread is called Crazy Plans ill take that as a compliment.Everybody needs a hobby...I think this counts as at least two. :cool:

Bill George
10-26-2015, 5:09 PM
Since the thread is called Crazy Plans ill take that as a compliment.

Joe, I thought you just wanted your GCC laser working and all I have heard about them is good. I almost purchased a used one before I got this ULS. I have done some CNC projects and its nice to have one done and working. I did use Gecko drives like you said you were looking at and they are top of the line. Good luck and keep us updated.

Joe Walmer
10-26-2015, 6:46 PM
The GCC laser is great~! it lasted 12 years with no problems. But I am in fear the mobo may go out at anytime and you cant get new ones.

So I can fix the GCC with a china tube but if the mobo goes out not only do I have to get a new one and figure out how to hook it up to servo motors but I loose the 1500$ I could get for selling it right now. The wheels are just about as sloppy as they can get without replacing them and that costs a lot.

So yeah I am in limbo on what exactly to do, sell the laser tube and mobo from my GCC now and get 3000$ or fix it up with a china tube and sell the synrad for 1200-1500$ If the mobo then breaks I have to rebuild it anyway.

I figure if i get the k40 gutted and put in my own open rail xy system then figure out the bugs of smoothieboard by then I will sell off the GCC mainboard because I have the k40 laser working. Then I can just put another smoothie board in the GCC laser so in the worst case I can replace the glass tube or motherboard if it ever goes bad.

Dave Sheldrake
10-26-2015, 7:43 PM
Over here it's known as "Heath Robinson" engineering...

Doing what works :) credit to you Joe, you probably are a bit crazy but crazy works for me :)

Kev Williams
10-26-2015, 10:49 PM
I'm just wondering why you assume the motherboard will die? I have 2 1989 Motorola proprietary computers, one runs nearly every day, the other not so much, both have all the original innards, including fans, the power supply and floppy drives! I also have a 1991 486 that I keep around to make font and job save disks for the motorola's. Of all the computers I've ever owned, and it's pushing 50 or so, only one motherboard ever went south, and that was a Packard Bell computer... ? :D

^^^knock on my head for all the above! ;)

And-- there's guys out there who love to fix that kind of stuff and are good at it...

Just sayin.... :)

Bill George
10-27-2015, 8:28 AM
Joe the K40 machine motherboard is not that great people are removing and updating all the time. Ligthtobject dot com has some great upgrades for that machine. But I have seen up graded K40 machines sell for pennies on the dollar on Craigslist and eBay.
The same upgrades could be used on your remodeled GCC.

Frankly if your afraid someday the GCC will fail then part it out and use the money to buy something like a Rabbit that uses universal parts you can get anywhere.