Laser Stops....

[fullingdale]

Hopefully someone can assist...

I have the LS3020 machine and last night, for seemingly no reason the laser stopped working mid cut, though the machine continued around the shape, as if nothing had happened.

I checked over everything that I could think of ... plenty of water, it's circulating and there's no bubbles or other stuff in the tube, etc., and everything is clean and dust free. I did notice that the water was a little warm, so assumed that to be the issue and just shut down everything. Came back to it again today, thinking maybe it just needed a little rest (reboot of PC, power down for a while and all that) ... checked the water and much cooler now that it's stood for the night.

Now it runs for a short period and then randomly stops again ... leave it a minute or two and it'll work ...

Following the speed settings that I have seen on here and in the manuals, it seems that the power should be around 10-12mA ... at that power, it cuts through 3mm perspex at around 20mm/s and gives a clean etch; similarly cuts 1.5mm acrylic at around 30-35mm/s, again with a clean etch. As this model doesn't seem make use of the "power" setting from the computer (despite what the manual says) ... I had been working a little on trial an error, using the speeds that are mentioned in the manual and online, steadily increasing the currency to obtain the finished results.

Could someone offer any advice on a few things:

1. Why would the laser stop firing like this?

2. What is the optimum mA setting?

I'm still a bit of a "noobie" so any useful information would be appreciated.

[PhillyDee]

I would check the door switch myself. I have had an issue with these on both my lasers. Make sure they work well. You will need a multimeter.

[fullingdale]

You will need a multimeter.

.... and someone who knows how to use one, lol.

Fingers crossed my mate will be around later to finish off some electrical work that he's doing ... I'll get him to check that as an option for me.

Being a switch (and I am aware of the risk in doing so, as the laser would effectively be 'live' with the lid open) could this be checked by simply jumping the wires ... just to rule the option out?

[PhillyDee]

Yes, disabling the stops would mean the machine is capable of running with the lid open and no safety barrier. I would never recommend this of course!

[fullingdale]

Before tinkering around at that level (cannot see quite what/where I would have to do this to test it), I have just been trying again ... and whilst I wouldn't rule that out ... it seems to be REALLY intermittent.

Simple image in NewlyDraw of a few scan circles (similar to the Olympic rings) each around 5mm ... engrave and it draws them happily ... move the origin to the right and go again ... still okay ... again ... laser stops after a couple, but when it positions for the next circle, I see that the laser fires for a fraction of a second (just like clicking "Shoot" in NewlyDraw) then nothing ... next circle, same ... move the position and similar happens, but stops at a different place. All the time, I was VERY careful not to touch the machine so that nothing is being nudged, etc.,

It's a bit of a pain as I have a small side-line business knocking out etched signs and this is obviously stopping everything.

Tried to cut/etch a sign that someone has bought from me ... simple rectangular (150mm x 50mm) cut from acrylic with some etched wording ... it's done the etched wording (which practically fills the area) perfectly, but when cutting the surrounding box, it's only done the first 50-60mm then stopped. As before, the laser head continues as if nothing has happened.

Pehaps the door catch could be the answer and may need looking at, but not being electrically minded it's not something that I could take on without clear instruction on doing so. Any thoughts on what my next steps may be? I emailed this same query to HPC earlier today an await any kind of response from them.

PS: If I did try to bypass the door sensor ... I would still have enough sense to keep the lid shut when operating it.

[PhillyDee]

Of course you would, but no one can ever say try it without as it opens up liability issues etc

I have ran many CNC machines over the years many of which have had the door interlocks disabled. It used to happen a LOT. Now, its quite rare. Of course, the things I run for my main job are capable of not just killing you, but grinding you to a messy pulp without even slowing down!

Does the meter on the front register when it is not firing?

[fullingdale]

No, the meter drops to zero when it stops

[fullingdale]

This morning, I ran some tests and with the power right down (1.25turns):

-- Cutting took 4 passes at 20mm/s
-- Etching ran at 150mm/s on that 2-colour acrylic sold by HPC

Running the power any higher than 1.25 and the laser stops firing when it's doing the cut.

This is all very strange and I guess that I am going to have to have a word with HPC to see if there's anything that can do/advise on this.

[fullingdale]

UPDATE ....

Just spoken to one of the engineers at HPC and he's of the opinion that it could be a power supply issue ... and is going to confer with one of the other engineers to see if they agree, then I guess it'll be a case of buying a replacement supply and giving it a go.