New tube engraving differently.

whmeade10
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New tube engraving differently.

Postby whmeade10 » Mon Mar 27, 2017 8:56 am

I just purchased a new 1000mm 45w tube to replace my 700mm 40w tube. It is cutting great but seems to be rastering text larger, like it is bolded. It seems like the beam is larger or something. Has anyone run into this problem or know what may be going on? It also appears not as crisp. The optics are the same.

Thanks, Bill

IMG_0496.JPG

IMG_0497.JPG

Techgraphix
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Re: New tube engraving differently.

Postby Techgraphix » Mon Mar 27, 2017 9:53 am

First thing i see is that the power is much higher, so too much heat which will melt outside the wanted vectors. reduce the power significant..
Second: you have to recheck the tube alignment. When the beam bounces along the walls of the lensholder, you can get similar results.
Check the burningmark when you test-fire on a piece of paper (low powersetting, please) The shape should be round and quite equaly filled.
When there is a problem in the tube (broken or loose murrior) you will get something like a half moon..

Kees

whmeade10
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Re: New tube engraving differently.

Postby whmeade10 » Mon Mar 27, 2017 8:33 pm

Thanks Kees, I just spent the last hour or so going through beam alignment. I have the laser hitting the center of Mirror 1,2, and 3. The beam shape on the heat transfer tape was round and looked good. Are there any settings in the DSP that can help? I really like the increase in power but it appears that resolution is suffering.

Bill

SWMS
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Re: New tube engraving differently.

Postby SWMS » Tue Mar 28, 2017 1:02 am

Have you checked the beam alignment at each corner?
I find I do one initial beam alignment, then check each corner. If it's off between each corner, I do it again and again till I can't get it any better. Lining it up to the furthest corner away from the laser source is not enough IMHO. Check your lens. Maybe it's got a bit of crap on it.

Check your table is level too.

I've found that sometimes changing one thing turns up other errors as you are just looking for it a bit more.

Case in point, my beam never hit the same point from front to back. There was a 3-5mm gap and I only noticed when I put in a new tube. So I went through the whole machine until I narrowed it down to the v-rails. The previous guy had put them on and they were as straight as a banana!

whmeade10
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Re: New tube engraving differently.

Postby whmeade10 » Tue Mar 28, 2017 6:10 am

Thanks SWMS, I will look closer at everything again. One of my problems is that there is next to no adjustment on the mirrors. I have a FS Hobby laser that I bought back in 2012 and it is now being controlled by one of Marco's LO X7 controllers along with one of his 45W tubes and cooled by a 600W mini chiller, which I don't know how i went so long without one. I use to use a 5 gallon bucket. The mirrors is sandwiched between an aluminum holder and a piece of 1/8" rubber. The only way to adjust the mirror is using three screws that smash the rubber. I need to invest in a better platform! Thanks for the tips and suggestions.

Bill

whmeade10
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Re: New tube engraving differently.

Postby whmeade10 » Tue Mar 28, 2017 8:15 pm

I just finished working on the alignment and I believe it is better but not the same yet. Not sure what to do next. I have it aligned where I hit the center of the ficus lens in all four corners of the laser bed. I am using a 50.8mm focusing lens and wonder if I need to try a 38.1mm lens. Would that change make a difference?

tansh
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Re: New tube engraving differently.

Postby tansh » Tue Mar 28, 2017 8:58 pm

Try slower engraving speed with lower laser power

resunltd
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Re: New tube engraving differently.

Postby resunltd » Thu Mar 30, 2017 4:48 pm

whmeade10

Curious what material are you using for the signs?

Thanks.

SWMS
Posts: 158
Joined: Mon Jan 06, 2014 4:28 am

Re: New tube engraving differently.

Postby SWMS » Thu Mar 30, 2017 10:02 pm

Could it be your laser beam diameter has changed since you have a different tube and therefore the focus depth has changed?

I am not sure if you know how to measure this but can help if you don't.

Tech_Marco
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Re: New tube engraving differently.

Postby Tech_Marco » Thu Mar 30, 2017 11:11 pm

To me it seems either over power or wrong focus point. Also, if you pay a little attention on the picture, you will see some 'shade' on the side. It look like that the burned was caused by 'reflection' beam from the laser tip and it was not a direct burn from the laser. So, do this: Remove the laser tip (cone tip) and do again. That should give you better result. Then, reduce power by 15~20% and do again. Please post back what you found after test


Marco


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