Slipping problem help needed.

[bluestorm]

Hi, I have a hpc laser cutter 3040 which is 3 years old, but for some strange reason only when engraving it seems to slip every now and then. I engraved 5 pieces and it did not slip once, I have re flashed the 6525 motherboard which I thought it had sorted the problem, but it's come back. it's a very annoying problem and is causing me waste. I would appreciate any help with the problem.

[SillyJokes]

I've had a similar problem in the past.

With my machine it was a dirty belt and drive wheel, I gave it a really good clean.