Laser On/Off problem

I have a Comgrow 5 Watt Laser/Engraver attached to my Ender 3 Pro. I have an issue with when the project first starts. After moving to the start location the laser takes too long to fire up and the head starts moving. I get about an inch of blank line before the laser starts. Once it starts it works great until the next power off to move the laser, then the delay happens again creating a gap (everywhere on/off occurs).

What setting can I adjust to prevent this? I am using Marlin 2.0.x and a BigTech SKR mini E3 V3. If someone could share their settings for this I would greatly appreciate it.

Have you measured the time between laser on and light? If so, how long is this? What speed are you running the laser?

Where are you getting PWM from the board? Marlin configurations and certain pins on boards can have very low update frequency. Way too low for what’s practical for lasers. Your case seems excessive if you’re able to move an inch before light is visible.

I am brand new to this. But I have the laser connected to the part fan on the board. When in LightBurn and I press the Fire Button, it takes about .5 seconds for the laser to come on. Would it help to increase baud rate from 11500 to 250000? Does that have anything to do with it? Thanks. Oh, I forgot to mention I’m running it at 41 mm/s at 255 power.

No, this isn’t the source of the problem. If my hypothesis is correct then it’s literally the frequency at which the fan is being updated that is the problem.

Is your machine capable of these speeds?

How are you specifying this?

I don’t know if Bigtreetech try to make it easy for these boards to be used for lasers but it’s possible there’s a special firmware build meant for lasers. If so, that would be the easiest.

Else this would typically require a customization of the firmware to enable Marlin to have a higher frequency, assuming the hardware supports it.

I’d suggest checking some board specific forums for this to see if people have done this.

I noticed this Topic from someone with the same board. You may want to connect with him.

Thank you. I will check that out.

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.