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Messages - Ya-Nvr-No

1
Tangent Corner / Re: Cam lobe generator ?
« on: October 24, 2019, 05:50:43 PM »
Still a little confused by the relationship with height and tip radius as I notice the tangent points can bite me if you assume they follow the triangle leg extension logic.
That's why I rely on cad to verify

Trying to get a handle on this to beable to write a function to calculate

2
Tangent Corner / Re: Cam lobe generator ?
« on: October 24, 2019, 08:01:02 AM »
Id forgot to post this image of two different ones
changed only the tip radius

3
Tangent Corner / Re: Cam lobe generator ?
« on: October 23, 2019, 03:37:11 PM »
Still did not follow all that last image but it gave me some ideas.
once i understood the tangent points i could create a circle from three points
then the light bulb came on and it all made sense
thanks again
Proves how we can not see the obvious sometimes. yep pretty simple.

will have to pass the info off to Art and see if someday he can fit it in. He does stay busy coding.

4
Tangent Corner / Re: Cam lobe generator ?
« on: October 23, 2019, 09:07:22 AM »
After I posted, went back and found I ASSumed some things and I was visually close, but mathematically wrong.  :-[
wish id have seen that webpage before i posted
will have to go back and re-address.
thanks for the link
another good brain teaser to fend off dementia  :'(

pretty cool functional device, it did remind me of the Wankel engine

5
Tangent Corner / Re: Cam lobe generator ?
« on: October 22, 2019, 10:52:22 PM »
I started with the image and then using an inscribed circle of 10
Started building the triangles, circles and tangent points then trimming.

seems the lobe circle is a factor of 1.5 and then slid back to a second triangle tip point.
using the intersection point a circle can be created to a tangent point then trimmed.

now to figure out how to work backwards from the needed lobe size.
or you can always scale the item to suit once drawn.

My way of proof of concept and grasping the idea



6
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.


7
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.

8
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.


9
General Mach Discussion / Re: Restart program
« on: September 17, 2019, 07:03:01 PM »
you could replace any m30 in a program with m99 it will never stop
I use them all the time for warmup routines or checking tool changer issues.
you don't need a m98 just in sub routine calls


Here is a rough example of stepping over and maybe drilling or spotfacing
#100=1
#101=1.5

M98 P1000 L1
M3
M98 P2000 L9
M98 P1000 L1
M5
M30

O1000
G0z1
G0X0Y0
m99

O2000
#100=#100+1
g0 x#100 y#101
g1z-.1f40
g4p1
g0z.1
m99

10
General Mach Discussion / Re: Restart program
« on: September 17, 2019, 02:54:53 PM »
M99