C-axis milling (lathe)

[MIL-TFP-41]

Hey all,

 

Been driving myself nuts over this one.

We are trying to cut 4 diameters on the face of a part. The output on the first hole (center is at C zero) is fine. However, now matter how we try any other hole (say at 90 or 180 deg) the output is wrong.

code:

---

G0 T0500

G94

M33

G0 G54 X20. C0. Z20.25

G97 S534 M13

Z20.1

G94 G1 Z20. F6.4176

G41 X22.0907 C354.806 F23.5551

G12.1

G94 G3

X24. C0. J1. F6.4176 (CORRECT)

X20. C2. I-2.(CORRECT)

X16. C0. J-2.(CORRECT)

X20. C-2. I2.(CORRECT)

X24. C0. J2.(CORRECT)

G13.1

X22.0907 C5.194 I-1. F23.5565

G1 G40 X20. C0.

Z20.1 F6.4176

G0 Z20.25

X20. C90. Z20.25

(SECOND HOLE C 90 DEG)

Z20.1

G94 G1 Z20. F6.4176

G41 X22.0907 C84.806 F23.5551

G12.1

G94 G3

X24. C0. J1. F6.4176 (90 DEG OFF)

X20. C2. I-2. (90 DEG OFF)

X16. C0. J-2. (90 DEG OFF)

X20. C-2. I2. (90 DEG OFF)

X24. C0. J2. (90 DEG OFF)

G13.1

X22.0907 C95.194 I-1. F23.5565

G1 G40 X20. C90.

Z20.1 F6.4176

G0 Z20.25

---

any ideas??

[crazy^millman]

What toolpath are you using to create the code?

[MIL-TFP-41]

I have tried a few different toolpaths, all with the same result(C axis moves are always off) This one in particular is Circle mill, the second hole is translated.

 

I have also tried to make a new toolplane to do this (rotate Z 90 deg), same code then also.

[Camdude®]

what i do is create the first hole at C0, then do a toolpath rotate about the pertinent axis.

[Reece L Gibson]

Can you share the file or a file that is close to what you want to do in any way?

[MIL-TFP-41]

I uploaded the file & machine def & post to then FTP.

 

c axis.zip located in the MCX2 directory

 

thanks!!

[Don S at Barefoot CNC South]

James I think the problem is your planes, I don't use wcs in lathe draw your arcs in front view then try.

[JDowe]

In the tranform rotate ops - change toolplane

to coordinates and see if that helps -

[MIL-TFP-41]

Thanks for the suggestions....

 

JDowe, that did not work.

 

Don S, The machine is a VTL, I created the arcs on the proper plane...I even used the VTL sample file for a start to make sure I was doing it proper.

 

Seems to me that this may be a post issue. When I rotate the part (90 deg) I need the C output to be 90 deg...I am getting 0 deg when using polar interpolation. When doing the long code, the output is correct.

 

Where the C axis is basically the Y axis when doing polar interpolation, if one rotates a toolpath, mastercam see's the Y axis as starting at zero? Just a theroy....

[Kyle Waters]

James,

Have you looked at your post already? It seems strange that the start and end of the toolpath look to be okay, yet after stating the g12.1 something is funny. I haven't used these toolpaths before, is there a seperate setting for incremental/absolute output?

[Mick]

I've sent a similar problem in CNC Sofware yesterday. On our MT's when we do a contour toolpath, for example, on a counterbore of a hole, and then use toolpath/rotate to achieve the other three holes (we are counterboring four holes in a pcd on the face), it outputs the correct C move, but also positions it at Y.

 

The first hole is correct, toolpath is centred on the radius of the pcd on X, and at Y0, but the next holes output the X value and Y values as the hole centres, but with the correct C movement. It appears that there is a problem within the post.

 

If I post with the generic Multi Axis lathe post, supplied with Mastercam X2, it outputs fine.