Chatter - to arc or not to arc.. that is the question..

[jasond]

Been getting some chatter marks lately on the curved areas. I dont fully understand the arcs, I read that the arcs may get rid of the chatter as it fixes the curves. Would it be safe to just do that on each design I work with or is it something you should use sparingly?

I even tried turning my speed down from 100IPM to 20 IPM and it still shows the small chatter marks.

Thanks!

[Adrian]

Arcs will always be more efficient than the alternative lots of little moves so I'd say use them wherever you can.

Of course you will need to use a Post Processor that supports them and your control software must support them to.

[Greolt]

Worth mentioning that arcs (G2 and G3) are only output by Vectric software in a strictly 2D toolpath (and if an arc PP is used)

Vee-carving and 3D will always be segmented arcs regardless of what PP is used.

Also check to see if your controller supports Constant Velocity.

Greg

[jasond]

I do have look ahead and CV enabled.

I always export of the software using the mach2/3 arcs/inch and the option I was wondering about was the curve fit vector option and fitting types, do I choose circular arcs here or bezier curves? Would it hurt to do this each time I use a vector with a lot of curves?

Does it just fine tune a jagged edge with curves instead of the block lines?

Here is a sample of what problem I am noticing at some places.

Its not all all the areas, some places have none or are barely noticable, others like where the arrow are where I am concerned with. (It may be the vector I was cutting from and thats why I was wondering if it was safe or a pro to use the curve fit option when using a vector with a lot of curves)

Thanks everyone!

[Greolt]

Couple of observations;

That looks like a vee-carve toolpath.
If that is correct, then it makes no difference whether you use an arcs PP or not.
Vee-carving will be short segment toolpaths.

Second, that does not look to me like a toolpath problem. It looks more like lack of machine integrity and or rigidity.

Best thing would be to post the gcode that produced that cut and we will take a look.

Regarding CV and Mach;

Start with CV turned on and every CV option turned OFF. Some are in General Config and some on the settings page.
Leave look ahead at the default of 20 lines unless you have good reason to do otherwise.
Tune motor acceleration to the maximum that retains reliability and positional integrity.
This is the settings to start with and most likely the settings to stay with.

A bezier curve is not an arc and will not be described as one in gcode.

Greg

[jasond]

Couple of observations;

That looks like a vee-carve toolpath.
If that is correct, then it makes no difference whether you use an arcs PP or not.
Vee-carving will be short segment toolpaths.

Second, that does not look to me like a toolpath problem. It looks more like lack of machine integrity and or rigidity.

Best thing would be to post the gcode that produced that cut and we will take a look.

Regarding CV and Mach;

Start with CV turned on and every CV option turned OFF. Some are in General Config and some on the settings page.
Leave look ahead at the default of 20 lines unless you have good reason to do otherwise.
Tune motor acceleration to the maximum that retains reliability and positional integrity.
This is the settings to start with and most likely the settings to stay with.

A bezier curve is not an arc and will not be described as one in gcode.

Greg

Thanks Greg, I am moving the machine in a week so I will have a good look over everything and retighten things up. I will also follow the suggestion I read on another thread of cutting one of the samples to rule out software issues.

The computer I am using is pretty slow, so not sure if it was "freezing" to cause the blocky movements.