burn spots on text

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passman
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burn spots on text

Post by passman »

Hi everyone
looking for some advice?
I have opt 6w laser and have been doing a bin of text work. But I keep getting burn dots on my work. Can anyone help,
The picture attached is an example
thanks :D
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keyring.jpg

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scotttarnor
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Re: burn spots on text

Post by scotttarnor »

In my experience burn dots like you show were caused by nodes being close together, I go into Node editing and remove as many nodes as possible.
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Adrian
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Re: burn spots on text

Post by Adrian »

Also check for crossings and loops in the text at those spots when you zoom right in.

A quick way to remove excess nodes if that is an issue is to use the Curve Fit tool.

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adze_cnc
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Re: burn spots on text

Post by adze_cnc »

Those "burn spots" appear to be at the start and ending point of each letter. There may or may not be excess nodes and loops at those points but I have my doubts.

If you look at the "l" in the word 'only' it doesn't have a spot. I expect that's because it is connected to the prior "n" and that is being cut as one unit.

Does your laser attachment dwell at the start and end of each vector? If so, I figure that's what causing this. Is there a setting to eliminate that dwell time?

It's hard to tell by the photo but: is that just excess soot at those points or is it over burn of material (i.e. a pitting of the wood)? If soot, you might invest in some of that paper-backed transfer tape that the vinyl sign people use (such as this https://www.cutterpros.com/paper-backed-transfer-tape ) to mask your material to avoid soot deposits.

passman
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Re: burn spots on text

Post by passman »

i don't think it the nodes i have just checked the file and it is were each letter and sections start
picture attached :D
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keyring ori.jpg

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Adrian
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Re: burn spots on text

Post by Adrian »

In that case Steven is correct and it's dwell at the start/end of each pass.

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Re: burn spots on text

Post by passman »

can anyone give me any help on changing that please :)

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adze_cnc
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Re: burn spots on text

Post by adze_cnc »

For that kind of help we would need to know what post processor (pp) you are using.

My initial guess is that the pp is using a spindle on command to turn on the laser and it has a command to wait until the non-existent spindle comes up to speed.

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scotttarnor
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Re: burn spots on text

Post by scotttarnor »

adze_cnc wrote:
Tue May 25, 2021 6:42 pm
For that kind of help we would need to know what post processor (pp) you are using.

My initial guess is that the pp is using a spindle on command to turn on the laser and it has a command to wait until the non-existent spindle comes up to speed.
And that is why I love this forum, the above response was fast and makes sense!
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wb9tpg
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Re: burn spots on text

Post by wb9tpg »

If it is a grbl machine enter $32=1 and try it again
Gary Mitchell
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passman
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Re: burn spots on text

Post by passman »

im using ooznest pp with a duet controller
i am still struggling with this if someone can help pls :D

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Re: burn spots on text

Post by Auger »

Since I get bored on rainy hot days like today, I figured I'd look at this problems a little bit.

What is the CNC machine you are using ??

I found this article, is this the laser you are using ??
https://i2rcnc.com/pages/i2r-discussion ... s-11422168

As they have stated above, and I agree with them, it appears that you are waiting for the laser to "spin up" before it starts to make it's pass on the letters, and then waiting to "spin down" before moving on to the next letter.

Looking at Ooznests website, they do have a help request form, but I didn't see any public forums. Personally I would speak with them to insure you have the latest and greatest PP they have for your CNC and Laser.

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Re: burn spots on text

Post by Adrian »

The spindle start/stop in the Ooznest PP is just an M3/M4 call there isn't any pause or delay in the file so I would presume that is being added in the control software itself.

The Jet On (laser) section uses the M3 call as well.

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Re: burn spots on text

Post by wb9tpg »

Adrian wrote:
Mon Jun 07, 2021 3:08 pm
The spindle start/stop in the Ooznest PP is just an M3/M4 call there isn't any pause or delay in the file so I would presume that is being added in the control software itself.

The Jet On (laser) section uses the M3 call as well.
Some of the GRBL like machines use M3 for fixed speed and M4 for varying speed (for laser). Might be worth a shot.
Gary Mitchell
Kentucky, USA

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