Have you considered external offsets for this? I have had moderate success
turning low lift cams with this feature.

I'm preparing the retrofit of a cylindrical grinder with LinuxCNC to
achieve camshaft and crankshaft grinding. With external offsets you don't
need a really precise servo spindle. A normal and well reduced VFD driven
spindle could be used and the X axis will follow the rotation.

The obvious problem I had is that to achieve good results with the lathe I
need a live tool to allow for lower spindle rpms. I'm working on that and
soon I should have a live tool to mill the cams.

With this approach you can use pretty simple g code and you only need a hal
component to feed the external offset as the spindle turns. By the way, the
cam data must be hard coded inside the component, I guess it could be fed
in by some method by I didn't get there yet.

Here are some tests I've been doing.

https://youtu.be/KzEPyKZ6Xjo

https://youtu.be/xjBXa6RHSPQ

Leonardo Marsaglia

El dom., 5 jul. 2020 20:24, Forums <[email protected]> escribió:

> I'm getting to the point where I need my own camshaft grinder.
>
> The question I have is the G-code. The grinder has 2 basic components, a
> rotary operation to turn the cam and a linear movement to move the grinding
> head. For simplistic sake, say the G-code is 360 deg with the
> corresponding X
> travel.  Say we start with a blank round cam. In each revolution of the
> cam,
> the grinding wheel has to step in an amount till it gets to final size.
>
> This can be done with and If and Else statement.
>
> I was looking at some of the Chinese CNC controllers which are cheap and
> stand
> alone and as this is a simple job, would be a good option but I have not
> been
> able to find one that has logic in the G-Code.
>
> I don't think feedback is required and step and direction would be fine for
> this project. It would need constant recalibration as the wheel wears. My
> question is, what would be a suitable bit of hardware to run LinuxCNC. Is
> the
> PI up to this as yet ?
>
> Thanks Wallace.
>
>
>
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