heat in the carriage

[Richard Rumancik]

Kev, I'm not sure there is an extra burn from mirror 1 or that is just dirt on the test card.

Agron, I believe that mirrors 2 and mirror 3 are identical. (If I remember correctly mirrors 1 and 4 have heat sinks on the back of the mirror plate.) Maybe you could interchange mirrors 2 and 3 and retest? (Or swap in different mirrors if you have any.)


If you are in a pinch and don't have spare mirrors you might be able to cut some "mirrors" from an old disk drive platter just to test the optics. They don't have to be circles - you could shear rectangles from the aluminum disk platter. I am not recommending this permanently, but just as a low-cost test if you don't have a budget to buy parts to diagnose the problem. Tradeoff between time and money. Using old disk drive platters to make mirrors has been discussed in separate threads.

Also, when you test, perhaps you could reduce the power and/or burn time. Set the power to maybe 10 or 20% and turn the laser on for a second or less (whatever it takes to make a tiny clean burn mark.)

It seems like there is a thermal issue going on during vector cutting - the heating effect seems to be causing shifting of optical alignment. So maybe mirror 2 or mirror 3 is heating up too much and warping the mounting system. Have you checked if either of these mirrors and mounts are getting hot? You might have to pull them out of the mount and touch the back to tell, unless you have some other way. (But keep in mind that removing and replacing mirrors can affect alignment.) You could also try to feel the back of mirror mount #1 to see if it is overheating.

I suspect that raster engraving isn't heating the mounts up as much so you seem to be able to get away with it.

[Dan Hintz]

I will step in and put a large sum of currency on a split beam heating the carriage...

[Gary Hair]

I will step in and put a large sum of currency on a split beam heating the carriage...

I'll take some of that action...

I have about $1.50

[Dave Sheldrake]

I will step in and put a large sum of currency on a split beam heating the carriage...

yup, pretty much the only way it can get hot is from action of the beam

[Bill George]

And since it all started with a tube replace/recharge.....

[agron zeka]

Well I did all sorts of tests but the the only thing left is split beam (as you are mentioning) how can I fix it when i don't see it in any of the tests. No sign of it. The Synrad company in Germany are not replying to any of my emails, which is very suspicious.

[Bill George]

Well I did all sorts of tests but the the only thing left is split beam (as you are mentioning) how can I fix it when i don't see it in any of the tests. No sign of it. The Synrad company in Germany are not replying to any of my emails, which is very suspicious.

I think its been covered but removing the tube cartridge and taking a close look at the lens or glass and then the next mirror up.

[Dan Hintz]

Well I did tests all day today and what I've managed to find is that after some time of cutting, the laser beam starts to fall from the center towards bottom of the carriage hole, even in mirror three, so the falling of the laser starts from mirror two to three. When it cools it goes up again. This is so far. And I will do the card test and send some pics. Thank you.
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the the only thing left is split beam... how can I fix it when i don't see it in any of the tests. No sign of it.

I'm not sure if the question was ever answered... are those multiple burn spots on the third and fourth cards the same test or separate? If it's the same test, the beam is splitting.

Also, you mention the beam axis is off-center... it drops visibly from the center on the latter mirrors? Where are you running these tests? Have you run the same tests at (0,0) and at the far extents of the bed? If the beam is shifting off-axis slightly at (0,0), it's going to be WAY off at the far extents... which means the beam is hitting the carriage.

[Mike Null]

Agron

At least two highly competent engineers here have suggested that the source of the issue is the tube itself. You say you refurbished it. I think you should send it out and have it professionally done or try it again yourself to see if the problem persists. It seems to me that you've exhausted your options with the mirrors.