High Speed Engraving

[Paul Phillips]

My question is, why can't I run my $30k+ Universal Professional series laser at 100% speed, and has anyone else run into this problem or is this just normal?
My problem; I had a rush job to do yesterday engraving some large corian panels, being under the gun to get them done ASAP, I started the first panel at 100p, 100s, as per my test piece which turned out perfect.
About half way through the panel the machine got out of sync and crashed into the left side on the x-axis somehow, throwing off the alignment and ruining the sign. A quick call to Mike Mackenzie for some trouble shooting and he told me there are too many things it could be to determine the cause but, try slowing the speed down and see if that helps, so I tried it at 100p, 80s, and finished the job without repeating the problem. (a thank you to mike for getting me through it!)
Some observations; the panels were long so I had to run the machine with the front panel open which may have caused a problem with the dust being properly extracted (air flow), I noticed a lot of dust buildup on the underside of the carriage, I used a 1.5" lens which means I was closer than normal to the surface of the corian, i.e. closer to the dust, so maybe dust was an issue somehow? I know some may think I'm being picky wanting to run it at full speed but I think for what the machine cost, it should work as advertised, am I being unreasonable, are my expectations to high or did I just get a lemon?
Frustrated Paul

[Scott Shepherd]

Paul, we run our PLS at 100% speed all the time. I can't say I've ever seen or heard about that issue you describe. Our machine, in 3 or more years of use, has never "crashed" any axis. It's been VERY reliable. I can't imagine dust being an issue at all. I think something else is going on. Maybe a corrupt driver? I'd call tech support and get the latest firmware (there's some secret way of upgrading that), and update the driver at the same time.

[Dan Hintz]

Paul,

I'm with Steve, something is wrong. I've had odd tweak stuff happen with my machine in the past that were associated with a bug in the driver (such as every run of a job slowly shifting to the left/right a few tens of mils, cumulative, until I reset the machine). What you're experiencing sounds like a failing motor drive cable, so steps are being lost (though it could very well be a driver bug).

[Richard Rumancik]

If there is an intermittent problem, then slowing it down may have got you through the job, but perhaps the problem is still there and will crop up again at any time. So I would be cautious in what I am running. You may need to do some test plots at 100S and see if the problem comes back. If there is a cable break or stepper-motor-driver problem (i.e. the electronics that controls the motor, not the software) the problem will come back again probably at the worst time. (I understand the ULS machines don't have encoders - correct?) So you will probably have to waste some machine time to see if it can be reproduced.

It is possible that a power line disturbance could do that. What do you have between the wall and the laser on the AC line? Anything else on the same circuit?

[Paul Phillips]

Thanks for the ideas, yeah, Mike mentioned that it could be related to a motor issue however, I will try updating the driver and running some tests to see if it happens again. Here is a pic of what it did.
221463

[Joe Hillmann]

That used to be a problem for me, the belt was loose and worn (i probably could have just tightened it but replaced it well I was in there) for the few day that it took for the new belt to arrive I just ran it as a lower speed and it stopped happening.

[Mike Troncalli]

I am running a much smaller Full Spectrum Laser but one of the recommendations from the manufacture is to NOT raster anything within about 1 inch of the edges of the machine. The laser head needs room for it's ramp up and ramp down as it is going through it's motion. I don't know if this makes any difference on a professional machine or not. Just my 2c worth.

[Paul Phillips]

The lettering in the picture is about .5" tall so I'm about 2" from the edge so shouldn't be a problem. It has a new belt (1 month old) because I had to have the whole x-axis rail replaced because of notches worn into it by a bad carriage spring, which all adds to the over-all frustration factor as you can see.

[Dan Hintz]

I am running a much smaller Full Spectrum Laser but one of the recommendations from the manufacture is to NOT raster anything within about 1 inch of the edges of the machine. The laser head needs room for it's ramp up and ramp down as it is going through it's motion. I don't know if this makes any difference on a professional machine or not. Just my 2c worth.
Depends upon the machine... with ULS machines, it's a problem you need to account for. I think it's the same with Epilog. Not a concern for Trotecs, if memory serves.

[Scott Shepherd]

Correct Dan, we can raster all the way to the edges on the Trotec.

Paul, something's way wrong. That's not normal at 100% by any means. You need to work through that with tech support. There is a part failure somewhere.

[Joe Hillmann]

have you tested the belt tension?

[Paul Phillips]

Scott, thanks, that confirms my suspicion.
Joe, I checked it and it seems to be where it should be.
I will talk to Mike Mackenzie about it some more and see what can be done.

[Michael Kowalczyk]

Like Scott said that's not right. We run our Trotec at 100% speed and power without a problem. Hope it is something simple and you get it corrected quick.