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Cutter Compensation

Experimenter
Experimenter

Hi,

i have an issue with the cutter compensation.

I work with Siemens 840 D SL on a CNC- Lathe.

The Problem I have is when I use the cutter compensation that the tool is driving far deeper into the workpiece than it shows in the program.

I really don't know why this happens.

I was trying to work a 1mm Radius with a 1.2mm Radius cutting edge.

I limited the tool to 0.9mm and it was driving to 2.667mm.

Is there a failure in the calculation or did I may use the wrong Tracking Point?

What ever I tried it was going to the same direction.

 

Maybe someone has already experience with th problem.

6 REPLIES

Re: Cutter Compensation

Esteemed Contributor
Esteemed Contributor

As a "stab in the dark" guess...

I've seen this a lot of places that program on the machine and are transitioning to using NX

How much cutter comp did you set on the machine?

NORMALLY

NX outputs the cutter centerline.  So the amount of cutter comp on  the machine is only the DIFFERENCE between the actualy and nominal tool diameters (e.g. you said the tool was 10mm in NX, but you are using a tool with an actual diameter of 9mm - machine should have 1mm (dia) cutter comp, not 9mm (dia) cutter comp)

 

ALTERNATELY

Yes, in non-cutting moves you can output contact data, and then on the machine you would enter the 9mm (dia) comp.

 

If this is not your problem, then maybe further info is needed.

 

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: Cutter Compensation

Experimenter
Experimenter

Sorry my fault

I didn't limit the tool I limited the cut region to 0.9mm to make shure the machine won't go any further.But that didn't work.

I have a lot of problems at the moment; specially with the lenght.

Every worked lenght is to short and radius comes out as not a radius.

We are messuring our tool with a Zoller and give the information via RFID to the machine.

I think that might be a point to start.

I'm in contact with our experts of the machine and CAM.

They should make it.

Will give the solution of the problem.

Re: Cutter Compensation

Esteemed Contributor
Esteemed Contributor

And of course, I missed the word "lathe" in your original post...sorry

 

Not sure about Siemens controls, but on all our lathes we set the tracking point to match what the operators touch off on the machine (for most tools, these are the 4 corners of the "box" around the corner radius).  Then we (almost) never use cutter comp (just fudge the X & Z tool offsets to get things into tolerance). 

 

Of course, then if the operator wants to use a different nose radius tool, we have to edit the NX tool, regenerate  the op(s) & repost the program.

 

Ken

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: Cutter Compensation

Experimenter
Experimenter

So we had our Mashine Builder here and we figured out that NX is missing out digits for the radius.

The Postprozessor has to be updated for that.

 

Actually we have 3 digits in the radius calculation but the control need more because it's not calculating by itself.So CAM has to give more information for cutting a radius.

 

Re: Cutter Compensation

Esteemed Contributor
Esteemed Contributor

So go  to the word that is outputting the radius (NC Data definitions -> "Word tab -> find/click on the word)

 

What format is it using?

- one specific to that word?  or something generic like "coordinate"?

(look thru other words to see if that specific format is used on any other words)

- if specific to that word, just click the "edit" button and edit the number of decimal places

- if shared with other output (or if you just want to be safe), click on the "new" button, name the format ("Radius" or whatever), and set as desired.

- save post

 

Compare posted output from before & after the change to make sure you got the radius changed, and nothing else.

 

Ken

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: Cutter Compensation

Experimenter
Experimenter

Well, i don't know what to do with this instructions.

I gave the problem to our support programmers.

They updated the post prozessor to get a 4 digit radius.

 

 

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