Low Power From K40

So I installed a Cohesion board Display and Camera on a k40. I already had the Light burn software installed for low wattage laser diode and wanted to use it with the k40 but after install the K40 was skipping steps during travel. I had to go into the firmware and reduce the max speed from 24000 to 2400 and it seemed to fix the issue. Now the problem is I can seem to cut anything, I have the laser at 80% and traveling at 8mms and with 5 passes I cant get through card stock. The watt meter is showing about 30 watts at 80%. I feel like the conversion might of been a mistake, I was cutting 1/4 ply with less power than I am trying to cut card stock. The laser is better aligned than it ever has been. I dont know what to do, am hoping it is a simple software change.

It wasn’t a mistake. :slight_smile: i’m sure it’s a setting somewhere - whether in LightBurn or on the machine itself - where we can get it back up to its true potential.

Keep in mind that any power setting you set on the laser itself will affect the Laserboard. The laserboard will modulate the power up to the maximum set on the machine - so if you have the machine set to 80% power, and LightBurn to 50% power, that’s actually 40% (50% of 80%).

Doublecheck all your settings and give it another shot …

@loather I double checked, the manual knob is at 100% the meter is reading 20 ma I think I had posted 30. Could it be the PWM is not correct for the power out?

Is there a way to turn off the PWM in the config file? Then I can use the manual knob to check that this is not a laser performance issue.

I have checked the pot on the machine and its putting out 5v on the center pin with the knob full CW. To eliminate the board, I installed the factory board and ran a test cut with the same result. I am finding it odd that no matter what I do I can only get 20ma to show on the factory meter. I must have damaged a connections somewhere when I changed face plates to add the display

20mA is overdriving the tube. A 40W tube such as in the K40 shouldn’t see more than 17mA, generally, and that’s running at full 100%. Try and keep it under 95% for best tube life - so most people set their pots between 15 and 16mA.

That said, definitely double-check all the connections, make sure the screw terminals on the ammeter are tight especially.

Also, ensure the power supply isn’t whining like a banshee when you fire the laser with the Laserboard. That could indicate you need to change your PWM period, which may help with the loss of power problem.