Re: [CAD_CAM_EDM_DRO] rough circle

First of all, I would suggest not using the x4 multiplier. This justs
wastes resolution. The DeskCNC controller is capable of outputting
something like 150kHz and you are only using about 12.7kHz at 3800mm/min
with the x4 multiplier. Higher resolution will make the machine
smoother, especially at slow speeds. Try changing this first. If it has
little or no effect on the rough cut then it is unlikely to be the
DeskCNC controller.

Try running the circles at high speed without cutting anything. Does the
movement sound smooth or can you hear vibration? If you can hear
vibration, try tweaking the drive tuning slightly(turn down P and D).
Does the vibration change or go away? At the same time check you haven't
got a mechanical problem such as a loose pulley or encoder.

Set the acceleration to maximum and make a short high speed move. Does
the machine vibrate when it stops? If so you need to play with the motor
tuning. It helps to draw a line on the motor pulley and watch it when
doing this test. You can sometimes see the oscillation better than
hearing it.

While cutting, try increasing the current limit. Does it make a
difference? If so, you are running too close to the limit and the drives
are having trouble folowing the commanded position.

Les

afogassa wrote:

> Hi all,
> got a 3 axis servo driven gantry, rutex + deskcnc, it's working
>ok,but when doing full or half circles using the cam generated toolpath
>the finish is not good at all, if I slow down the feedrate to about
>1000mm/m it gets better but still not good enough.
> I'm wondering if deskcnc does not have the necessary speed when using
>two axis the same time or it's the servodrive is not fast enough to to
>correct the possition.
> It's not facets, it's more like the tool gouges in as if I was using
>a dull endmill.
> It has a 2.5 lead leadscrew 500 ticks encoder, and x4 multiplier on
>servo drive.
> so, it's a 0.005mm per step with a max speed set at 3800mm/min.
>that's = 200 steps per mm.
>
> Any sugestions.
>
>
>
>
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