Another new toy, a Laser welder

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Re: Another new toy, a Laser welder

Postby Jerry » Sun Jul 28, 2013 12:04 am

Last thursday I cleaned the optics and got the resonator lasing. I dont think the internal power meter is quite working right. I couldn't get the shutter to open, eventually figured out I need the doors closed on the cabinet to do that. Friday night I managed to set a paper towel on fire. Good progress.

I brought the push wheel switches home last night to repair them. They have a little plastic arm inside that acts as a spring to return the buttons after they have been pressed. Over the last couple decades these cracked and are no longer spring like. I stuck a soft piece of rubber in its place and that seems to work fine.

I took them back over today and reinstalled them. They work pretty good now. While I was there I decided to install the cutting head back on the Z slide. When I did this I found it was grossly out of line with the center line of beam. I spent the next hour realigning everything. It looks like this was the way it was when it came from the machine builders.

Got everything tuned in pretty well. I just cant get it to stabilize to a stop. The motors just dither, real annoying. I am getting pretty close to ditching this software and moving to LinuxCNC.

For fun I decided to see what it could do, I put a coke can in there and brought it into focus and fired away, here is the damage, not bad for old flash lamps and hammered cavity optics:

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Re: Another new toy, a Laser welder

Postby Jerry » Thu Aug 01, 2013 11:18 pm

Last monday I took the water pump apart to see what I could do about the mechanical seal, the only sources for the OEM seal are in the UK and at probably over $100 shipped I figured it was worth a try to see if I could find a replacement. It is a pretty standard seal, Aluminum oxide on one side, graphite on the other. 12mm shaft and a 26mm bore on the casing. I found a seal that matched these dimensions on Amazon for $6.20. What do you know it worked! I also changed the motor bearings while I was at it, they were pretty dry.

I knew the output coupler was pretty toast and I had never checked the high reflector. I found a new HR for an ESI laser that I had in one of my parts bins. Right diameter, wrong thickness. I took it over a couple nights ago to see if I could get it to fit. When I pulled out the old HR I found someone installed it backwards! OOPS! The new HR fit more or less and and I got 114w on my laser power meter. Not terrible, I guess. A new HR is about $300.

I have been put in touch with a company that works with Lumonics lasers and I am going to have then redo the coatings on the rod soon now that I know this beast works.
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Re: Another new toy, a Laser welder

Postby Doug Coulter » Fri Aug 02, 2013 11:02 am

I notice in the still that it seems to have skipped over the pull tabs, which are thicker than the rest of the can. Was that focus/thickness, or did you move them out of the way for the cut? How far down the side of the can does it cut?
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: Another new toy, a Laser welder

Postby Jerry » Sat Aug 03, 2013 5:48 pm

With aluminum only absorbing about 5% of the light at 1064 the beam does not need to be out of focus much for it to loose effectiveness. The walls of the can can be pretty thin and colored so that makes them easier to burn. And aluminum melts at 1200f so it makes it easier there.
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Re: Another new toy, a Laser welder

Postby Jerry » Mon Nov 04, 2013 2:20 am

I got the board set over a month ago and ended up also getting a 7i69 board that will allow up to 48 more points of IO and will tie directly into Opto22 IO Racks via 50 pin flat cable.

Getting a working computer system together has been hell. The first setup (Pictured below) had issues, I could not connect to the mesa daughter boards. Turns out there was something strange with the PIII single board computer in the case. For some reason when set to a 133 mhz buss the 5i25 card became unhappy. Only this card though, all the other cards, USB, WiFi, and firewire were happy. This took a while to figure out and started a hunt for a board that would work. I ended up finding a P4 SBC that would fit in to the existing backplane on ebay and it is working the best out of all the motherboards I have tried, getting about 10000/10000 under the latency test after a couple days running it. It was not without problems though. The board had bulging caps which I replaced (Damn RoHS solder) and then the thing would lock up linux after about 8 hours and I was getting a SMI pulse. I reset the BIOS to fail safe settings and all the problems went away, even the SMI issue.

I was hoping I could use a firewire c-mount camera I have to add computer vision to the machine but it really kills the machine when displaying video. Linux has been a pain with that. So many little things with firewire and simpler things like the touchscreen.

So now that I know my machine will actually work I have started putting the panel together. I ended up ditching the old roll around console that the guy was using before me. I got a 2'x3' JIC cabinet to put everything in. This will hold the computer, drives, and all the IO stuff. This is pretty much everything screwed down, I need to start wiring next.

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Advantech 19" rackmount by macona, on Flickr

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Laser welder drive panel by macona, on Flickr
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Re: Another new toy, a Laser welder

Postby Doug Coulter » Mon Nov 04, 2013 12:14 pm

I haven't even tried firewire on linux, but with a p4, you're going to have issues displaying high-rez video at high frame rates. There are "things you can do" on a regular mobo with some software twiddling to offload a lot to a GPU, but it's marginal even then. Remember, back when the p4 was the hot stuff, vidchats were 320x240 and 10 fps tops.

On the other hand, I'm having decent results with one of the newer HD webcams from Logitech, USB2 interface. Takes a little tweaking, but it's not eating the machine if I don't go for full rez and full screen. The "auto-everything" stuff is a PITA in some cases - it'd be nicer to fix focus and F stop for a lot of things, I might find a workaround for that (I believe it exists in the windows drivers for the camera, but linux doesn't seem to use factory drivers for this camera at all - it just comes up automatically at full rez and speed and no obvious way to acess the built in "features").
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Re: Another new toy, a Laser welder

Postby Jerry » Tue Nov 05, 2013 12:41 am

I just tried the firewire camera with the P4 and it works great. 640x480 @ 30fps with no noticeable hit in system latency. Even at the higher resolutions it is happy. I am using a Point Grey Scorpion. http://ww2.ptgrey.com/Newsletters/archive/jun2003.html

The tech from Point Grey has been extremely helpful even though I got the camera second hand. That is getting pretty rare.
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Re: Another new toy, a Laser welder

Postby Doug Coulter » Wed Nov 06, 2013 1:08 pm

That looks like a really good option. Seems as if you get real control over the camera that way, too. It's been a real pita to get even good fusor pix around here, since the camera auto-focus tends to obsess over the wrong thing, the exposure ditto, and to get a decent pic takes some fiddling, putting things manual/locked, and fooling around a bit. Else I get a perfectly focused and "color-balanced" picture of the stainless steel screen mesh just behind my viewport...The fusion, happening 16" further away is ignored by the camera guts. And you can imagine what "auto color balance" does to something that has something glowing red hot in the middle of a purple plasma. Taking pix of machines in action - similar set of issues. That glint off something that makes the part you wanted to see dark, instead of just clipping on the glint? Without manual control, good luck with that!
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: Another new toy, a Laser welder

Postby Jerry » Mon Mar 17, 2014 11:01 pm

Its been a while since I posted about this guy. Between the thermal cameras and the vacuum system I have been preoccupied.

So, I now have the drive and power panel assembled. Hooked it up to the servos on the machine and it all works controlled through linuxcnc. At least I can move stuff around. I have not messed with the control of the laser from linuxcnc, that can wait. Pick below of a semi finished board, it has been cleaned up with some wire molding to keep things somewhat in place.

Image

I went through a couple different designs for the control panel, I got a 24"x30" cabinet and had a control panel cut out for it on the laser at work as well as a bulkhead for the servo cabinet for the cables. Not cheap, about $130, but a lot easier than trying to make it myself. The left side will hold the 19" rack mount 8U PC display and the two 4U controls for the laser.

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I plasma cut the openings in the JIC cabinets this weekend and tried to powder coat the control panel and bulkhead plate. The powder went on thin and I am just going to have to paint it.

Image
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