Author Topic: Loss of resolution  (Read 474 times)

micky

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Loss of resolution
« on: September 11, 2020, 03:33:01 AM »
I haven't made any changes to my regular settings, but my engravings appear to have become faded, and they lack resolution.

I engrave onto leather. My lettering is usually about 18mm high, and my laser is set at 3000 / 0.05 / horizontal.

You can see the difference in the two images attached. One engraving from a few months ago is much blacker than the other from a few days ago. This faded appearance has happened on my last five or six jobs. It possibly coincides with a Windows update. It might also possibly be to do with the quality of my latest batch of leather, but I'm just not sure.

Is my laser failing maybe? Or can anyone recommend adjusting a setting that would give me better resolution?

Thanks!
« Last Edit: September 11, 2020, 03:35:34 AM by micky »

Zax

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Re: Loss of resolution
« Reply #1 on: September 11, 2020, 04:17:47 AM »
It is probably the material.

You mention a resolution and horizonal engraving but the example is a vector job, are you raster engraving an outline?

Have you changed anything with the firmware parameters or laser max settings?

Is 3000 the engraving or vector feed rate? It seems high, what power laser module?

micky

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Re: Loss of resolution
« Reply #2 on: September 11, 2020, 08:06:18 AM »
Hi Zax. Honestly, after lots of trial and error with your software a few years ago, I know how to do what I need to do - engrave my customers names on leather - but otherwise I haven't got a clue. I don't know what raster engraving or vector feed rate means. I type the words into a word processor - I use the snipping tool to cut a rectangle shape round the words - and then I open the image file in T2. I definitely haven't changed any of my settings.

Are you seeing anything in the photo of the lighter engraving that would make you think my laser is failing? Do they fail gradually, or suddenly? It looks to be functioning exactly as normal.

If the laser isn't failing I think the answer is probably going to be the quality of the leather. I use oiled leather, similar to old style biker jackets, so it could just be that I've bought a batch thats been over-oiled, or perhaps the manufacturers have used a new type of vegetable oil.

Thanks again for your help.
Mike.

ggallant571

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Re: Loss of resolution
« Reply #3 on: September 11, 2020, 08:12:32 AM »
I find it useful to have "generic" test patterns. The one I am currently using does lines at different spacing (0.10, 0.15, 0.20mm).

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Having the start/end points offset mean I can see the line gaps with a microscope. Do this for both horizontal and vertical burns at various speeds and power. Currently it is hard coded into my host burn application. Probably could dump the gcode to a file but you would need to manually edit for your environment.

Diode lasers do expire. Suspect the hobby grade have a relatively low life expectancy. I have 3 dead ones!!

Does leather emit an oily smoke? Have you cleaned the lens?
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micky

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Re: Loss of resolution
« Reply #4 on: September 11, 2020, 08:17:31 AM »
Yes there is an oily smoke, and no I have never cleaned the laser - but I will do that today! Thanks.
I know this is a daft question, but what should I use to clean it?
« Last Edit: September 11, 2020, 08:19:47 AM by micky »

ggallant571

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Re: Loss of resolution
« Reply #5 on: September 11, 2020, 09:09:48 AM »
Its should be a glass lens.My guess would be some sort of solvent that dissolves oils. Perhaps a before/after test burn on the same material.
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Zax

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Re: Loss of resolution
« Reply #6 on: September 11, 2020, 11:52:42 AM »
If you aren't doing filled text then raster engraving (what you are doing) may not be the best way to do it, you could use Sketch to enter the text directly in T2Laser and run it as vector (should be much faster). The only exception is if you need it thicker than a single laser line width.

The laser diodes can degrade slightly and then stabilize, but when they fail it's usually immediate and either no output or a very dim spot.

You may just need to clean the lens but I think the material is probably a little different.

micky

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Re: Loss of resolution
« Reply #7 on: September 12, 2020, 11:05:51 AM »
I think Iíve solved this now.

I went back through my workflow, and I found that if when I typed in the text of my engraving on my word processor, I shrank the page magnification slightly, then followed all my usual steps as stated above, the engraving came out just slightly bolder / blacker.

So at least I know my laser isnít failing. I cleaned the laser with a bit of white spirit too. No muck came off, and the glass seemed to be spotless.

I think my laptop and word processor both updated recently, and thatís what caused this problem. But itís sorted now. Thanks for your help gents. Zax Iíll definitely have a think about the steps youíve recommended, but as I said, if it does what I need it to do then Iím happy to just leave things alone.