Hello Guest it is September 26, 2020, 06:32:46 PM

### Author Topic: Turn | Is eccentric turning possible with Mach4?  (Read 916 times)

0 Members and 1 Guest are viewing this topic.

#### Ya-Nvr-No

• 992
##### Re: Turn | Is eccentric turning possible with Mach4?
« Reply #10 on: October 08, 2019, 01:08:59 PM »
Guess I'm not following your math; as plotting out a 30 degree stock rotation does not prove your calculation. Either by staying on the stock center line or the eccentrics tangent point, witch would be its center line.

So guess I need educated on your logic or I'm not following your descriptions.

I'm a big proponent of CAD drawings to visualize and verify.

For me I can see a Cool idea for a macro on my 6 axis lathe, but I will still need to calculate in tool nose radius for my use.

Thanks for the inspiration. I do some arcs, wedges and twists now but never looked at eccentrics.

#### Ya-Nvr-No

• 992
##### Re: Turn | Is eccentric turning possible with Mach4?
« Reply #11 on: October 08, 2019, 01:42:49 PM »
What it seems to follow is the blue circle. Created from the offset dimension.
(CAD, Created from 3 tangent points) The offset tangents points.

Another good tool I use is the spread sheet and formulas I can follow.

It would be interesting to see the plotted results from your formulas.
Sorry I just don't follow them or know how I would use them in a macro. But they are interesting.

Or I am all wet and am not following this threads topic at all.

#### BR549

• 6,932
##### Re: Turn | Is eccentric turning possible with Mach4?
« Reply #12 on: October 08, 2019, 02:07:11 PM »
Check with Les over at Sheetcam. Years back he helped me with applications to CAM out Crankshaft grinding and Camshaft grinding using Sheetcam to create teh Gcode. Both functions are about what you want to do with OD offset grinding. I have teh plugins here somewhere but Less might remember doing it as well.

(;-) TP

#### Graham Waterworth

• 2,159
• Yorkshire Dales, England
##### Re: Turn | Is eccentric turning possible with Mach4?
« Reply #13 on: October 08, 2019, 07:45:21 PM »
Here is my experience.

If you have an eccentric that you can approach from the Z axis you can use the XC way to produce the eccentric.

Tool stays on the centre line and the C axis rotates and the X axis moves in sync plus and minus to follow the shape while feeding to depth in Z.

If you are in a groove like a crank journal then the only way is with XY & C axis,  the X&Y do a G02/3 move that is the same radius as the offset of the eccentric while tied to the C rotation.  This is milling mode on most lathes. So

The main problem is the max RPM, I could only do 400rpm and that was on a Mazak Integrex i400S with a smooth control. There was nothing faster at the time.

« Last Edit: October 08, 2019, 07:49:07 PM by Graham Waterworth »
Without engineers the world stops

#### Ya-Nvr-No

• 992
##### Re: Turn | Is eccentric turning possible with Mach4?
« Reply #14 on: October 10, 2019, 10:36:45 AM »
Thanks Graham for the followup

thought id show using excel graphing the two formulas, first from joe's then mine.
more to illustrate how you can use VBA array and functions in excel to display data.

« Last Edit: October 10, 2019, 10:39:47 AM by Ya-Nvr-No »