Turning of the Elliptical Profile

[Mechanizer]

I am trying to turn an elliptical profile, (Concave in shape),major radii 101.5 and minor radii 98.8, using Pro-E 5.0 manufacturing/turning/turn profile. Radius of tool 2.123mm
Pro-E get it arc. I tried different strategies

1.Pro take it one arc when use arc only in circular interpolation
2.Eight arcs when points& arc
3.About 200 points when points only in "parameters"
Third one was the latest approach with the defect that profile get "Kinks" or fringes(rough) with using these points with G01.
Its a ellipse so no Circular interpolation can be used to get finished profile.
Isn't any way for Elliptical Interpolation or get a large number of points of profile in manufacturing.
I have tried Microsoft excel to give points of elliptical profile with 1 micron increment, but machine is not taking tool compensation for such a minute increment.
Please help me out. I am doomed

 

[DiamndBrent]

I'm not sure if I understand your problem, and I have no experience with turning, but do you mean elliptical milling or elliptical turning? If milling with an endmill, it's just a matter ofusing POINTS_ONLY for CIRC_INTERPOLATION and setting the TOLERANCE parameter to something small, say .0001 or smaller. That may work for turning too, I don't know.

That would be a pretty specialized lathe to elliptical turn, which Pro/E might not support. Is this for a piston? That's the only time I have ever heard of elliptical turning.

 

[eddie]

I am desperately trying to accomplish the same thing. I have communicated with PTC on this a few times. I have not been able to make anyone understand exactly what is needed.<?:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" />


In our situation the code for the machine needs to be A, X, Z.The turning functions in Pro MFG do not seem towork that way. At least that I have been able to discover. I did almost arrive at a solution depending onthe requirements. I could not makeit work with the one micron, one degree increment we required. ProE would simply lock up or crash. It would survive at a bit larger increment though.


My workaround solution/trick was to create a spiral curve from equation on a plane above my part. I then projected the curve on to the toric surface (face). That curve then becomes a mill surface trajectory for a ball nose end mill. The ball nose radius is set to the turning tool nose radius. I created a milling machine with a rotary table. The spiral is then cut by rotation ofthe rotary table.I then created a custom post that would output the A, X, Z data required by the lathe to make the cut happen.


Your mileage may vary. If you do not needmicro increments this trickery might work for you.

 

[Mechanizer]

Hey guys Good News!
I have figured that out 4 days ago with successful machining. Although it is not the solution in Pro-e because with "Points only" it gives only 200 points in my dimensions.
Here is the solution: Use Macro(Parametric) Programming using CNC Machine variables.i.e give X axis values with increment and correspondingly write formula of Ellipse on Z-axis, using machine variables(parameters).
And repeat the steps using IF condition loop.For radius compensation use ellipse equation using major and minor radii minus tool radius.
It works nicely. You can make program even in nanometer increment and with only 1 KB tap file size or few lines.
Consult your machine manual for Parameters. They are usually P1,P2,P3....P200
e.g P1=21.5, P2=52





Edited by: Mechanizer

 

[cpoirier]

I have a question.
Are you saying that turning at speed (proper speed and feed) your machine tool is able to move in both x and z while keeping in sync with the spindle? At least to some point where you are happy with the results? This must be a huge part with very small changes in x and Z? Are you rough machining a mirror or just some type of test piece for education?

Sounds cool.
Chris

 

[Mechanizer]

@ cpoirier
The results were quite satisfactory even prefect, leaving no tool mark or feed mark. As it was Diamond turned the finish was quite amazing.
The size of the Part is small 102 mm Dia
As for feed is concerned it get automatic compensated with in crease in dia.