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More Mirrors and Mounting the Thing

A project log for Building Another Laser Cutter

Building a laser cutter around a Coherent GEM-50L laser

Jerry BiehlerJerry Biehler 02/24/2021 at 05:220 Comments

Last night I did some more work on the optics, got the basic alignment to the front plate done and also found it does have the Enhanced Pulse Mode that the larger version of the laser has. It sends twice the power to the laser which can increase the pulse output by 3x, so about 180w pulse out of the laser for this one. The PWM duty cycle is limited in this mode though to 50% so your average power is probably about the same. 

I made up the block to hold the rest of the mirrors to the front plate. I just decided to use some Hysol 1C to glue the mirror blocks together. 1/2 hr later at 230f the blocks were nice and solid. I did have to make a spacer to clear the ATFR mirror block. 



I also got some label tape for my label maker and made labels for all the controls on the control box. 



I am getting to the point where I need this thing mounted to the mill to finish the alignment and figure out the rest of it. I knew I wanted to mount it to the dovetail for the ram, but not sure how. the dovetail is way bigger than any cutter I had and on top of that it's a non standard dovetail angle. First thought was come up with a plate and a couple round bars that would go in the dovetails, some bolts would push them into place, I had some 30mm round linear rail that would work nice. That is until a hack saw just bounced off it. Looking around I saw a chunk of some sort of continuous cast hollow bronze I have had lying around for years, I have about 6' of it. Perfect size to fit in the dovetail. Took a couple 6" pieces of that and faced and chamfered the ends. Had some 20mm thick aluminum plate to attach them to. I figured if I made one side fixed and the other with holes that fit the bolts tight at the bottom and counterbored so they are looser at the top and then have the hole centers slightly smaller than the center to center distance of the rounds in the dovetail that when I tightened the bolts on the loose side it would draw it in and tighten it all up. And boy does it. It's rock solid. I have another chunk of aluminum plate that will attach to this to make a shelf that the laser assembly will sit on. 

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