OMTech 80w AF2435-80 laser not firing under 10% power

My laser will only fire under 10% when I set the power using shape properties.

I did a material test on black Leatherette, which requires very little power to get just through the top layer in show the bright silver underneath. I set the material test up using one layer at 450 mm/s/100% max power/20% min power, and then set the power for the individual squares through shape properties setting. I found the best settings at 450 mm/s and 2% power.

When I try to run the job setting the layer at 2% power, the laser doesn’t fire. The only way I’ve found to get it to fire at 2% is to set the layer at 100% max/20% min, and then set the shape properties at 2%. The work around works, but would rather not have to try to remember to verify individual shape properties each time. I checked vendor settings in Machine Settings and it showed minimum laser power was 2%. I changed that to 1% and it didn’t change anything.

I had a similar issue with my Xtool D1 using lightburn where it wouldn’t fire under 10 or 15% or something like that. I got around it by increasing speed to compensate. This 80w laser is too powerful to do that though. I’m running max speed I can do for engraving without pushing acceleration limits or losing overall engraving time.

Anyone else experience this?

You weren’t clear, but I assume it’s the 80W co2 that isn’t firing below a certain percentage… ?

Most dc excited co2 lasers won’t lase below around 10%, as they get bigger this percentage can increase, mainly from physical size differences I believe…

You can set the minimums/maximums within the controller and that will override Lightburn (or anyone else’s software) control over min/max values in multiple areas.

There are theories about running at low power where the tube isn’t actually lasing, but on the brink of lasing… seems to be not a realistic way to operate…

I’m not sure what you are doing, but if it won’t lase at 2% from the console, it couldn’t (shouldn’t) lase fiddling with the numbers to get an obfuscated 2%…


Keep in mind that when you set your power to 50%, you are lasing 100% power for 50% of the period…

Make sense?


I thought leatherette was a vinyl based product… ?

:smile_cat:

Thanks for the reply! Both the diode xtool D1 and my co2 won’t fire below a certain percentage, but it’s the co2 I’m really asking about.

I’ll try to clarify what I’m doing again…

When I set a layer to 2% power, it doesn’t lase.

When I set that same layer to 100%, but then adjust the shape properties for that specific layer/shape in lightburn to 2% power, it lases and I get the exact effect I’m looking for on the material.

Make sense? So I can get the laser to fire at 2% when I set it in shape properties, but not when I set the actual layer to 2%.

My understanding is when you set shape properties to “x” percentage power, it fires at “x” percentage of whatever you have the layer set to. So if I set shape property to 10%, and have the layer set to max of 50%, then the laser will fire at 5% for that specific shape. Let me know if that’s not correct or if I’m mistaken.

Based on my understanding above of how shape property setting works, I just don’t understand why I’m able to get the laser to fire at 2% when setting it in shape properties, but not when I set the overall layer at 2%.

It’s likely the minimum of 20% power that’s changing the results in a way that’s leading you to misinterpret what’s happening. If you put minimum to 0% I suspect your results with shape properties at 2% will be the same as if you set shape properties at 100% with layer power at 2%.

I’m not certain how minimum power is handled with shape properties power scale but I’m fairly certain that power levels for both max and min are not both scaled proportionally as you’d expect. I know I’ve seen behavior that surprised me when I first explored this.

So you’re suggesting that it’s not really firing at 2% due to the min value setting. I hadn’t considered how min value has an impact on that shape property setting.

I’ll do some more testing with the min power value in mind. Will see if I can get the laser to fire at a low setting like I need for this particular material.

What is the minimum power you have set in the controller? It’s probably not a problem, but you should be aware of it.

:smile_cat:

I set the min power in the controller to 1%. It was already 2% by default set by the vendor (OMTech).

I would doubt you can lase your 80W at 2%, that is my problem with this.

I have my minimum in the controller set to about 9% …

I can’t explain what’s happening… I’d have to hang a scope off it… :face_with_spiral_eyes:

:smile_cat:

Yes. That’s my hypothesis. There’s nothing that power scale is doing that wouldn’t otherwise be accessible elsewhere. And we know that 10% is typical lowest power to lase with that value increasing with higher wattage tubes. This should have been listed in the OMTech documentation.

:rofl:

Couldn’t resist… I don’t think OMTech ever saw my machine, let alone added anything document wise to the purchase… IMHO…

:smile_cat:

I found the documentation surprisingly sparse and generic but that part did stand out to me.

I believe you. It’s probably not lasing at 2%. I don’t have an understanding of how shape property power setting is impacted by the layer min power.

Yeah… it’s not entirely clear to me either but I do know that it caught me as not obvious. Or rather, it was in contrast to my initial unconsidered notion of it. After thinking about it I realized there could be a few different ways it could be handled and didn’t explore it further to work back specifically how it was actually handled.

I’d welcome you to chase it down and report back though. :wink:

Some possible implementations:

  1. Max and Min both scale directly based on their current value. So 100% at 20% power scale goes to 20%. 20% at 20% power scale goes to 4%. I think we can rule this out based on previous evidence but deserves to be looked at more systematically.
  2. Max scales but Min does not. So 100% at 20% power scale goes to 20%… however, 100% at 10% power scale goes to 20% also due to 20% minimum.
  3. Min scales but not linearly with power scale.
  4. Some other mechanism I haven’t considered.

I’m hoping someone who’s actually looked at this can step in.

What kind of speeds are you running?

Are you aware of the start speed in the controller?

Something has to make sense here :face_with_spiral_eyes:

:smile_cat:

I’m running 450 mm/s. That’s fastest I can run for fill engrave before it actually starts taking longer to engrave due to my acceleration settings.

I reran some test settings. Something must have been wonky when I did my initial material settings test. Maybe I didn’t have the shape properties set correctly or something, because now 16% power seems to be the sweet spot for this material. When I ran the material settings test I started at 15% power and went up to 25% and all the squares were completely torched… way too powerful. I must not have set the individual shape properties correctly or something. Not sure.

Anyways, I seem to have it figured out now at 450 mm/s, .09 LPI, and 16% power. Thank you all for your help, and sorry I may have wasted your time with my bad info.

On a side note, I’ve discovered 8.8% is the lowest power my laser will fire. 8.7% I get nothing, but as soon as I bump to 8.8% I can see the laser fire on the material. Good to know the lowest setting I can run at least.

I’d stay above the lowest value. That value will change as the tube temperature changes…

Good luck

:smile_cat:

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