Non-circular boring. (Linuxcnc fun)

[skunkworks]

The speeds are dictated by how much acceleration/speed the machine has. If I run the spindle a lot faster faster - the polygon will not look like a polygon...

Hal is linuxcnc's hardware abstration layer. It is sort of the interface between linuxcnc and the outside world. It allows you to create virtual circuits and logic to do as you please.

Yes I realised what was going on there, I did not know the timing of course. You cutting feeds and speeds are quite low, is that because of limitations of your mill or the software or was it to make a watchable video?



That would be great. It would save reinventing that wheel.

Getting back to the HAL file. Am I right it assuming that is what drives LinuxCNC and you use a Gcode to HAL converter to be able to use Gcode from a CAM programme or hand written.

[skunkworks]

Hmmmm.

[skunkworks]

Vertical lines are the effect from the low spindle encoder resolution.. Above tool path cut in aluminum..

[tonyfoale]

Vertical lines are the effect from the low spindle encoder resolution.. Above tool path cut in aluminum..

Of course that begs the question, "what is the encoder resolution"?
I love the twist. I guess that you repeat a subroutine with a coordinate transformation every spindle rotation?
Really neat.

[skunkworks]

I used a some gear tooth sensors and a gear for the encoder.. It is only around 38 teeth so 152 counts per rev.. (which was fine for most threading/rigid tapping) I just added twist functionality to the comp. You send it the Deg/Rev

[tonyfoale]

I used a some gear tooth sensors and a gear for the encoder.. It is only around 38 teeth so 152 counts per rev.. (which was fine for most threading/rigid tapping) I just added twist functionality to the comp. You send it the Deg/Rev

So for the twist you tell it that you have 355° (or appropriate number) per revolution?

I have close to 100 teeth so I would have a resolution of around 1°.
Currently I have two pickups for a single pulse. One for a cheap tacho and the other for an index pulse. My intention is to add a couple more to pick up on the teeth.
As the spindle speed is close to constant, for a task like this I think that one could get away with some pulse frequency multiplication to fake better resolution.

Click images for full size.

[skunkworks]

If I want the polygon to twist 60 deg in .5 inches (the photo) I send it 60/.5=120. Gear tooth sensor are not that expensive - Although I don't t now the availability in france.. \

I used allegro ATS667LSGTN-T


sam

[skunkworks]

Lathe mode...

[skunkworks]

Now finally starting to upgrade the encoder.

[skunkworks]

Almost there...