Intermittent Laser Cut - tear along dotted line!

[puffernutter]

Playing with the laser/engraver I had from here a while ago and I've hit an interesting issue. It will not power the laser continuously when cutting. I am using LightBurn and they have ben very helpful and looked at the software files as well as my machine set up and there is nothing there. This leaves to wonder if it is the Laser Power Unit.

So, before I spend out money on a new one, has anyone come across a the issue where the LPS pulses the output - is it a failure mode? It is a consistent width.

I have tried the Pulse Function and on Manual in fires once for a given period and on Continuous it pulses - so it does seem linked to the LPS.

Thoughts please?

Peter

 

[MattH]

A dotted line is usually caused by moving to fast, to low laser power or focus not right. It might look like the laser is pulsing but from my experience using 4 different C02 lasers that’s not the case.

Next time you have this issue, put something thinner under the laser and use the same settings, you’ll find it cuts fine. Proving there is no pulsing.

 

[puffernutter]

A dotted line is usually caused by moving to fast, to low laser power or focus not right. It might look like the laser is pulsing but from my experience using 4 different C02 lasers that’s not the case.

Next time you have this issue, put something thinner under the laser and use the same settings, you’ll find it cuts fine. Proving there is no pulsing.

This is a definite on/off pulse. Nothing to do with speed. When using the "Pulse" button on continuous - it pulses! There is a associated pulsing of the LED in the LPS.

Cheers

Peter

 

[puffernutter]

I've just removed the "Control" plug (commands from the processor) from the LPS and pressed the "Test" button. It pulses, so I assume the LPS is the issue?

Cheers

Peter

 

[m_c]

Can you scope the control going to the laser?

I'm not sure what kind of laser you're using, but both CO2 tubes, and Diodes have limited lifespans.

 

[puffernutter]

As above, I've isolated the laser from the control commands, pressed "Test" and it just pulses.

I've ordered a new power supply. The tube has had less than 30 minutes use so far.

Cheers

Peter

 

[MattH]

If the tube has been recently installed then I’d check the cathode connection, any arcing could cause intermittent output.

 

[puffernutter]

If the tube has been recently installed then I’d check the cathode connection, any arcing could cause intermittent output.

Thanks for that pointer, I'll have a look. What is strange is that it is very regular pulsing, I would have expected any arcing to be more irregular. I hadn't noticed it on any of the engraving I've done, it has only really manifested itself when I started engraving on cork and wanted to cut the design.

Peter

 

[puffernutter]

Last night I had a few minutes, so I'd thought I'd investigate if arcing could be the problem. I opened the rear panel and checked the connections, placed a piece of material under the head, donned my safety goggles and pressed pulse. No sign of arcing, or even pulsing, a continuous beam. I then thought I'd try a shape, I had a small square as a test piece. That was fine, continuous along all 4 edges. It didn't cut through, so adjusted power and speed and had three or 4 more runs with it running continuously. So, it isn't the software.

On the next run, it started pulsing again. So I come back to the LPS, is that getting warm and something starts to break down? I've checked it's rating and it should be OK for the tube (both 50W). My new LPS is not due for a couple of weeks, so we'll see what happens.

However, it is certainly a hardware issue!

Peter

 

[puffernutter]

Amazon were amazingly quick! New Cloudray LPS fitted (different connectors, different fixing centres!) But I got there, it’s working and (for the moment - touch wood) no intermittent cut! I’ve actually cut a square out of my cork! Woo Hoo!