Need Help Laser intermittent power C3D

Machine: Ebay 40K Laser

Board: C3D

Firmware: _Smoothie

Problem/ Question: Im using lightburn, but why the laser is doing this intermittent power issue.

check video here :

Thanks in advance for your help.

It looks like your acceleration in the corners is very low. What is the config setting?

@paulf8080 Thanks for answer, here is my C3D card configuration.
config.txt (28.4 KB)

After I send you the config.txt I change the delta_acceleration from 100 to 2500 and is working much better is not doing the same but I see in the laser panel when the red led is solid on when doing the X axis but a little flickering when doing the Y axis.

In lightburn the speed is 10 at 50% when I increase the speed to 20 at 50% you can note the flickering more in Y axis.

What is the Max I can put in delta_acceleration and what is delta_max_rate?

A axis

delta_steps_per_mm 55.5 # may be steps per degree for example
delta_step_pin 2.3 # Pin for delta stepper step signal
delta_dir_pin 0.22 # Pin for delta stepper direction
delta_en_pin 0.21 # Pin for delta enable
delta_current 1.0 # Z stepper motor current
delta_max_rate 6000 # mm/min
delta_acceleration 2500 # mm/sec²

Thanks again in advance for the help.

Hi Angel,

Please provide pictures of your machine, control panel, board, other electrical components, and wiring so we can take a closer look. We need to see everything.

Please provide additional details:

  • How old is your laser and the tube you are using?
  • What are you using to cool the tube (cooling setup and type of coolant)?
  • Do you hear any buzzing or see any arcing near the LPSU or tube when you increase the %?
  • What wattage is your tube?
  • Do you have a digital panel or analog setup with a milliamp meter?

@Starla thanks for try to help but is not about the laser old or tube or cooling system, wattage of the tube because all was working fine until I change C3D Mini board.

I think is about settings, what I say before when I increase the delta_acceleration from 100 to 2500 is doing better, I don’t have problem with power when doing a line in the X axis is when doing the Y axis.

Also I switch back to the factory mini board to see if is something with the power supply or something else but is working perfect again is only when i switch to C3D mini and that is why I think is something in the setting I have to change.

I have digital panel with a analog amperemeter. the 60% in digital power is my real 100% power (16 amp)
but again is nothing about my equipment.


Hi Angel,

The reason I asked for all of this information is because it helps rule out potential paths to go down during the troubleshooting process. I still need to see pictures of your entire setup in order to understand what we are working with here.

Without this information, diagnostics will not be possible. How would you like to proceed?

Again the problem is not the hardware, is working fine until I change the C3D mini board, I put back the original board and works fine again, I submit before my config.txt here is again or check previous post for the link if this one don’t work. Config.txt
It’s about setting, I read in the forum and most of them say is about setting in the config.txt.

What I have is a K40 chinese blue box, the setting in display, power etc. I reply to you directly in the previous post with that information, and the video of what is doing it’s in my original post.
Are you have the time to check my Config.txt file to see if is something wrong there?

Thanks in advance.


What type of rotary are you using? What are the specs on the stepper motor(s) for your rotary? This will determine what values to input into the parameters on the configuration file. I would love to help, but I need more information to be able to do so. Your delta steps per mm seems a bit high, but I need details to know for sure.

If you haven’t read our rotary setup guide yet, you may find this helpful:

Hi Starla, thanks for answer.

My stepper Motor is 17HM19-1684S is a .9 deg I already make the rotary wheel turn 360 deg (one Turn) with the delta steps per mm with 55.5 because I think is because a .9deg with 400 micro steps and not a 1.8deg is 200 micro steps.

I’m using in Lightburn rotary setting A axis the roller diameter and if I use the Y axis i leave 360 So for that steps per rotation. For rotation I think I’m ok I make the square and measurement is ok in X and Y.
My problem is in the power or I think pulses check this video and you will see how the flame is not constantly and is braking in some areas in the line, also if you see the previous test in the tumbler same video you see the line is intermittent and don’t burn the complete line, that is what im talking about.

Stepper module configuration

microseconds_per_step_pulse 2 # Duration of step pulses to stepper drivers, in microseconds
base_stepping_frequency 100000 # Base frequency for stepping

I change base_stepping_frequency from 100000 to 50000 and make an improve but still skipping but less the I change to 12000 and look like works ok and the flame looks constantly but the that change reduce the speed and I don’t know if that is good or that can affect something else, sorry I don’t have a video for that.

Let me know if I need to do some adjustment in this setting increasing or decreasing the microseconds_per_step_pulse and base_stepping_frequency or something else.