Increase engrave speed > Time goes up?!


#1

I’m testing a non-proofgrade material (Rowmark Lasermark, 2-ply acrylic), going through a load of settings to get it right.

I notice that when all is kept the same, but I increase the engrave speed, the time to etch/cut goes up - which makes no sense to me. For example I increased the engrave speed from 500 to 1,000 (everything else the same), and the time went from 4:30 to 5:05.
36 PM

Has anyone else seen this or can anyone explain why? Is it a bug?


#2

Takes longer for the head to decelerate at higher speeds? (At a guess.)


#3

same orientation ect? If so it probably has to do with the way the GF has to do its deccelerations. Because it is an open loop stepper system and not closed loop it needs to maintain specific decceleration limits so it doesn’t skip steps and lose positioning.

higher speed means it takes longer to slow down and the increase in speed isn’t totally absorbing that time.


#4

Yes same orientation. Interesting, thanks to both of you for the suggestion. I wonder then for a large piece of artwork (this is only 1" sq), if the time would then go down instead of up. (More etch time to deceleration ratio).


#5

It should. It is also why if it will fit then you should do your engraves with the long side to the X direction of the machine. You reduce the # of lines the GF is doing and thus the amount of times it needs to turn around.


#6

Thanks! Makes sense.


#7

Indeed. As the speed goes up the active time engraving goes down as the reciprocal but the time to accelerate increases proportional the square root of speed over acceleration. So there is a sweet spot speed for minimum time which could be calculated if we knew the acceleration.

For wide engraves the active time dominates but for narrow ones the acceleration time becomes significant.


#8

This question is outside our team’s scope. I’ve moved it to the Beyond the Manual so the discussion can continue there.