VisiCut & Fractional speeds ...

Added by drogon almost 10 years ago

So cutter now running fast with the genuine Pololu drivers in-place and the current limiting set appropriately. The Stepper motors are actually warn now, and the controllers running at an acceptable temperature. (ie. hot enough to burn, but not so hot that your skin vaporises ;-)

However - it's running too fast )-:

With a max. speed of 500mm/sec in the config file - it will go faster, but... the issue now is that to cut 3mm acrylic, the speed in VisiCut needs to be about 1.5... But it seems that either VisiCut or the firmware on the mbed is not accepting that. I've been timing it and it seems that anything > 1.0 is the same as 2. (which is too fast to cut all the way through)

So can anyone confirm that this is the case (ie. not accepting fractions?)

To get round it, I've had to slow the motion.speed down to 100 to give some leeway in the %speed settings in VisiCut - which I'm finding somewhat irksome as moves are now at that speed, and uni-directional engraving is much slower (to the point, I've moved to bi-directional which looks just fine to me)

I've not dived into the code yet, but am I correct in thinking that motion.speed is for moving and cutting, and x.speed, y.speed applies to engraving? (x,y.speed is 500 and engraving is flying)

If so, I wonder if this could be altered in any way? - needs 3 sets of parameters as I see it: non-cutting moves, cutting moves and engraving... I'm running the engraving at 100% speed, 80% power and it's working rather well (and fast - although the laser makes a bit of noise now)


Replies (3)

RE: VisiCut & Fractional speeds ... - Added by peteruithoven almost 10 years ago

LAOS can't handle fractional numbers in it's simplecode, but therefore things like power and speed are multiplied by 100. So 1% becomes 100.
Motion speed speed is indeed for cutting. Not sure if it's also used for moving.

x.speed and y.speed are used for engraving, see note 1 on the config file page.
One remaining issue is that you can't control speed of engraving anymore from VisiCut, see issue:
This is actually part of a bigger problem, we should update GRBL

(I would always use bi-directional movements for engraving)

If you need to use 1.5 to cut anything useful I would just lower the motion.speed and motion.accel.

RE: VisiCut & Fractional speeds ... - Added by drogon almost 10 years ago

Thanks for that - just noticed the 100% engraving speed thing too, but that's OK - PWM is working, so I can reduce the power.

Now seem to have issues with opaque vs. transparent acrylic needing different powers to cut. It's never easy this stuff..


RE: VisiCut & Fractional speeds ... - Added by t-oster almost 10 years ago


as you can see in VisiCut's source:

I set the speed to 100 * (speed value as float) and then casted to int.
This means fractional speeds up to the detail of 0.01 should work.