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TNC ERROR: Circle end pos. incorrect

Solution Partner Pioneer Solution Partner Pioneer
Solution Partner Pioneer

 

Hi, 

 

I´m having a problem with some TNC postprocessor made with PostBuilder 10.0.3.0.

This error is reproduced in more than one machine.

 

The error that appears in the control is: "Circle end pos. incorrect"

 

Circle_end_pos_incorrect.JPG

 

 

 

 

 

 

 

 

MP7431.JPG

 

 

 

 

 

 

I usually increase the value of MP7431, for example, If it was 0.01 I would raise it to 0.015 and the error would be solved. 

 

But this customer won´t to increase this parameter. 

 

Anybody knows how to resolve this issue? Any ideas?

 

I have also tried to fix the error by modifying the variable mom_kin_machine_resolution, but it has not worked.

 

Best Regards 

Ivan

 

7 REPLIES

Re: TNC ERROR: Circle end pos. incorrect

Esteemed Contributor
Esteemed Contributor

Best is to change the operation to only output linear moves.

Changing the post-processor to do this will just result in bad surface quality.

Stefan Pendl, Systemmanager CAx, HAIDLMAIR GmbH
Production: NX10.0.3, VERICUT 8.0, FBM, MRL 3.1.4 | TcUA 10.1 MP7 Patch 0 (10.1.7.0) | TcVis 10.1
Development: VB.NET, Tcl/Tk    Testing: NX11.0 EAP, NX12.0 EAP

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Re: TNC ERROR: Circle end pos. incorrect

Legend
Legend

hi,

 

- change machine parameter (your suggestion)

- try to generate operation in tighter tolerance

- try edit resolution to 0.0001 and edit formats to 4 decimals

- or set operation output to linear as Stefan said - but you have to say goodbye to circles

 

I have no better idea at the moment

But I am curious how people solve this problem too.

 

 

---------------------------------------------
#♫ PB, 5ax, itnc, nx, vericut ♫ #

Re: TNC ERROR: Circle end pos. incorrect

Esteemed Contributor
Esteemed Contributor

In addition you could change the PP to output radius instead of circle end-point.

Change from:

CC ...
C ...

to:

CC ...
CR ...

CR only supports circles <=180° if I read the Heidenhain programming guide correctly.

Stefan Pendl, Systemmanager CAx, HAIDLMAIR GmbH
Production: NX10.0.3, VERICUT 8.0, FBM, MRL 3.1.4 | TcUA 10.1 MP7 Patch 0 (10.1.7.0) | TcVis 10.1
Development: VB.NET, Tcl/Tk    Testing: NX11.0 EAP, NX12.0 EAP

How to Get the Most from Your Signature in the Community

Re: TNC ERROR: Circle end pos. incorrect

Legend
Legend

you know, when you want to do 180deg cirle it outputs  CRs:

1.CR XY R

2.CR XY R

3.CR XY R

4.CR XY R

(and split to quadrants ofcourse)

So tool goes from present position to XY with R radius. Maybe it is possible to get not precise circle.

Because CR doesnt care circle center (CC).

 

My experience with full circle:

Customer wants CC + C because he thinks about problem above.

So I made it. CC + C + full circle setting.

Problem:

55 CC X Y
56 CP IPA+3312 Z+130 DR+
57 C X Y

after CP IPA tool is on the floor of the hole - somewhere. You dont know the XY of this position,

CP IPA  entered just angle.

Then cleanup circle is following.

If tool after cpipa is behind C XY position,  it does just tiny arc to get to C XY position.

Bez názvu.png

Only if tool after cpipa is on or in front of C XY postiion it will do full cleanup circle.

Differencies are really small. You dont know where machine stops after cpipa.

-> So we split even this CC + C to quadrants.

---------------------------------------------
#♫ PB, 5ax, itnc, nx, vericut ♫ #

Re: TNC ERROR: Circle end pos. incorrect

Esteemed Contributor
Esteemed Contributor

I've seen this on Okuma mills.  With both IJK and R output.

 

What I traced it to is circles where the arc radius is "5" in the decimal place BEYOND the machine precision.

E.g. (inch units)

machine precision is .0001

Arc radius = .xxxx5

 

It was easier to test/fix by using R (rather than IJK) for arc output.

What I did in the post is to add (or subract? - it's been a while so I've forgotten) a really small number (.000001 or whatever) to get it to round in the direction the machine wants, but only in that case (so I don't do it if the radius is .xxxx4 or .xxxx6)

 

I'd test on the machine - manually change the radius in the last decimal place (up and down 1 unit) to see if one or the other works.  Then look at the internal toolpath (or output the mom variable to more decimal places) to see what the actual radius is.

Then figure out what you need to do.

Ken Akerboom Sr CAx Systems Engr, Moog, Inc.
Production: NX10.0.3.5 MP5 + patch/TC11.2
I'd rather be e-steemed than e-diseaseled


Re: TNC ERROR: Circle end pos. incorrect

Solution Partner Pioneer Solution Partner Pioneer
Solution Partner Pioneer

Hi, 

 

Thank you to all. 

 

I have tried many solutions but no one finishes solving the problem. 

 

  • The client does not want to change the MP7431 parameter.
  • Obviously drawing the toolpath by lines it works, but  I want to resolve circles problem. 
  • Generating operation in tighter tolerance or resolution to 0.0001 and editing formats to 4 decimals the issue decreases but not solve in all of cases. 

  • I don´t like output the circles with CC CR so explains Juraj

 

If the calculated toolpath goes by defined points that form a circle with its respective center.

Why do not the mom_pos_arc_center and mom_pos variables draw the same path?

 

Best Regards

Ivan

Re: TNC ERROR: Circle end pos. incorrect

Esteemed Contributor
Esteemed Contributor

kizitomusampa wrote:

If the calculated toolpath goes by defined points that form a circle with its respective center.

Why do not the mom_pos_arc_center and mom_pos variables draw the same path?

 

Best Regards

Ivan


I have heard that NX is outputting circles in 120° sections and that MOM is adding circles together and splits them to 90° sections.

It seems that this results in the floating point error any recent computer is suffering from, which in turn results in circles being unreliable.

Might be better to just use what NX offers for post-processing, since 120° sections are good and there is no need for 90° sections then.

Stefan Pendl, Systemmanager CAx, HAIDLMAIR GmbH
Production: NX10.0.3, VERICUT 8.0, FBM, MRL 3.1.4 | TcUA 10.1 MP7 Patch 0 (10.1.7.0) | TcVis 10.1
Development: VB.NET, Tcl/Tk    Testing: NX11.0 EAP, NX12.0 EAP

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