Strange lines on engraving, any ideas?

Hiya everyone,

If anyone could point me in the right direction about this it would be most appreciated. For the last three years I have had a couple of lasers, both of which are the Chinese 50w and 60w. Both have served me very well and I have only had to replace tubes and lenses once on each in that time, so I consider myself to be relatively lucky. Anyway, just before Christmas I invested in a second 60w laser cutter from China due to demand and have set it up much like the others. However when I am engraving on this latest machine I seem to get the following bumpy vertical lines effect on the wood? Sometimes it is quite strong like the picture attached and sometimes it is quite light and hardly noticable, however my other machine do not do this, does anyone have any idea what it could possibly be?

Whilst it still engraves perfectly fine, I am a bit of a perfectionist and I notice these lines quite strongly when it has finished a project, as such I have had to temporarily not use my newest laser due to this problem.

I haven't done much research about the problem to be perfectly honest, I was kind of hoping someone would see it and instantly know what the problem is (appreciate that's a big assumption though lol). If anyone could offer any advice etc, I would be most appreciative.

Thank you very much in advance.
Chris

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Chinese lasers do that, only way you get 100% around it is to buy a RF laser (us laser). You can however make it better by lowering your interval setting. Try lowering it. Each interval lower will slow down the laser as the passes will be closer together (think of lowering the interval as increasing the dpi) and the picture will improve.

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Originally Posted by Chris Lanky

Hiya everyone,

If anyone could point me in the right direction about this it would be most appreciated. For the last three years I have had a couple of lasers, both of which are the Chinese 50w and 60w. Both have served me very well and I have only had to replace tubes and lenses once on each in that time, so I consider myself to be relatively lucky. Anyway, just before Christmas I invested in a second 60w laser cutter from China due to demand and have set it up much like the others. However when I am engraving on this latest machine I seem to get the following bumpy vertical lines effect on the wood? Sometimes it is quite strong like the picture attached and sometimes it is quite light and hardly noticable, however my other machine do not do this, does anyone have any idea what it could possibly be?

Whilst it still engraves perfectly fine, I am a bit of a perfectionist and I notice these lines quite strongly when it has finished a project, as such I have had to temporarily not use my newest laser due to this problem.

I haven't done much research about the problem to be perfectly honest, I was kind of hoping someone would see it and instantly know what the problem is (appreciate that's a big assumption though lol). If anyone could offer any advice etc, I would be most appreciative.

Thank you very much in advance.
Chris

Attachment 335622Attachment 335623

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I would make a black rectangle in your art program and see what it does with that. Considering the same file works with the 2 other lasers it's not the artwork. Just curious what 100% black would do.

Did you check for a loose bearing or belt yet? The 2nd picture, the backwards L in the banner looks pretty tight... If you had a loose part I would expect to see it in that un burned area in the 2nd picture.

Just some Wild Guesses...

AL

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Originally Posted by Keith Winter

Chinese lasers do that, only way you get 100% around it is to buy a RF laser (us laser)...

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Or use the other Chinese laser... :rolleyes:

Haha! I suspect his other does it too but the interval is set closer so you cannot see it without looking closely.

Howdy and thanks for all the replies so far. Couple of things to clarify though.

The other Chinese lasers don't do this at all. And I have increased the interval / dpi setting and it's exactly the same. I've even increased it quite dramatically to slow the laser right down and it's still the same as this was the first conclusion that I came to as well. After playing about with the setting a little more I was able to see the effect it had by lowering the interval setting and then increasing it.

If it helps, the laser sweeps horizontally across the board, but the lines it leaves behind are vertical. If i've messed around with the interval / dpi and had that setting it too low, it would create horizontal lines?

Additionally, sometimes after I have used the laser a few times in one day, the lines are not there at all? It's definitely a strange one!!!

Interval was my only guess, my Chinese looks like that when the interval is larger, less so when smaller intervals. However I assumed this was horizontal indicating interval if its vertical lines I'm not sure. Maybe someone else can chime in. What happens if you rotate the grain of the wood, same thing ?

I've never run across banding on the Y axis like that. Is the material in the pic plywood by any chance?

What, exactly, are you seeing? What I see is the wood grain contrast being increased by the burn... those horizontal lines are the ray flecks turning darker brown than the surrounding wood. But perhaps you're looking at the picture differently and seeing a larger pattern...

OOOOOOOK... it is not often that I embarrass myself like this... but I am a great believer that when you feel should change your middle name to dumba**e that you put your hands up and admit it...

After reading everyones comments I started to wonder if the belt was loose, I checked this and everything appeared to be exactly fine, so what else could it be then??? So I had a look around and then came to this...

Attachment 335687\

That little gold screw in the side obviously allows the shaft of the laser to be taken off so you can access the focus lens. But it would appear this screw, whilst attached, was not actually screwed in to prevent the shaft from bopping up and down. So after tightening this up as much as I possibly could and then restarting the laser the problem seems to have gone away!! I am of course monitoring this though incase it is just a random coincidence, but so far everything appears to be great and no vertical banding...

Excuse me now whilst I crawl back into my cave of shame!!! :(

It's kind of surprising that no one brought up the standard loose lens or mirror diagnosis. So I wouldn't feel too bad...

No worries happens to us all Chris ;) :p Glad you got it fixed, cheers!

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Originally Posted by Chris Lanky

OOOOOOOK... it is not often that I embarrass myself like this... but I am a great believer that when you feel should change your middle name to dumba**e that you put your hands up and admit it...

After reading everyones comments I started to wonder if the belt was loose, I checked this and everything appeared to be exactly fine, so what else could it be then??? So I had a look around and then came to this...

Attachment 335687\

That little gold screw in the side obviously allows the shaft of the laser to be taken off so you can access the focus lens. But it would appear this screw, whilst attached, was not actually screwed in to prevent the shaft from bopping up and down. So after tightening this up as much as I possibly could and then restarting the laser the problem seems to have gone away!! I am of course monitoring this though incase it is just a random coincidence, but so far everything appears to be great and no vertical banding...

Excuse me now whilst I crawl back into my cave of shame!!! :(

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