VMC with C Axis (Rotary axis around Z)

[Mick]

I have a rotary axis fitted to the table of a VMC, and it is a C axis, rotating about Z

 

We're using it to drill a large bolt hole circle, and the bolt hole circle is larger than the Y travel of the machine, so we want to move the tool in X and C to achieve the required BHC.

 

Because of the setup of the C axis, and the part, we have the C axis mounted to the right side of the machine, and the workpiece origin is the centre of rotation.

 

How can I force Mastercam to keep the tool in the X- position and rotate C? When I create the toolpath, it wants to move to X+ and then rotate accordingly. Even when I choose the first hole position in the X- position.

 

Has anyone ever enountered this?

[Jeremy Herron@DBS Solutions™]

Do you have use_twist in your post Mick?

[Mick]

use_twist? Never heard of it, and so, no, I dont

[crazy^millman]

Pretty Straight forward. You will need to Create a WCS rotated to the correct C position. The nake sure the Machine Def knows where the Rotary is sitting then it should output the correct C axis rotation. If not then You might just have ot hard code in the C axis using a mi/mr to accomplish it.

 

HTH

[Mick]

I tried creating a WCS, but it keeps forcing the X position to X+

 

I guess this is a case of Mastercam assuming that X+ positioning is the desired positioning.

[Chris Bloedorn]

Try changing your machine def to this...

[CJep]

I have a rotary axis fitted to the table of a VMC, and it is a C axis, rotating about Z

 

We're using it to drill a large bolt hole circle, and the bolt hole circle is larger than the Y travel of the machine, so we want to move the tool in X and C to achieve the required BHC.

 

Because of the setup of the C axis, and the part, we have the C axis mounted to the right side of the machine, and the workpiece origin is the centre of rotation.

 

How can I force Mastercam to keep the tool in the X- position and rotate C? When I create the toolpath, it wants to move to X+ and then rotate accordingly. Even when I choose the first hole position in the X- position.

 

Has anyone ever enountered this?

 

Mick,

Here's how I set it up,... select a point for the drill toolpath in the neg X, 09:00 looking from the top, then use a toolpath transform for the rotary output,...

I set the type to "rotate" method to "toolplane" source "NCI" then in the rotate page set the number of instances, I set the angle to start at zero and the second is the angle between, the rotation view is set to "Top"

 

I'm using the MpMaster to output the code below, I changed the axis of rotation in the "A" axis properties in the machine def

 

N50 G28 Z0.

N55 T1 M06 ( 1/2 SPOTDRILL)

N60 G00 G17 G90 G54 A0. X-5.75 Y0. S1675 M03

N65 G43 H1 Z.125

N70 M08

N75 G94

N80 G99 G81 Z-.125 R.125 F16.5

N85 G80

N90 G91 G28 Z0.

N95 G00 G90 A45. X-5.75 Y0.

N100 G43 H1 Z.125

N105 G99 G81 Z-.125 R.125 F16.5

N110 G80

N115 G91 G28 Z0.

N120 G00 G90 A90. X-5.75 Y0.

N125 G43 H1 Z.125

N130 G99 G81 Z-.125 R.125 F16.5

N135 G80

N140 G91 G28 Z0.

N145 G00 G90 A135. X-5.75 Y0.

N150 G43 H1 Z.125

N155 G99 G81 Z-.125 R.125 F16.5

N160 G80

N165 G91 G28 Z0.

N170 G00 G90 A180. X-5.75 Y0.

N175 G43 H1 Z.125

N180 G99 G81 Z-.125 R.125 F16.5

N185 G80

N190 G91 G28 Z0.

N195 G00 G90 A225. X-5.75 Y0.

N200 G43 H1 Z.125

N205 G99 G81 Z-.125 R.125 F16.5

N210 G80

N215 G91 G28 Z0.

N220 G00 G90 A270. X-5.75 Y0.

N225 G43 H1 Z.125

N230 G99 G81 Z-.125 R.125 F16.5

N235 G80

N240 G91 G28 Z0.

N245 G00 G90 A315. X-5.75 Y0.

N250 G43 H1 Z.125

N255 G99 G81 Z-.125 R.125 F16.5

N260 G80

N265 M09

N270 M05

N275 G91 G28 Z0.

N280 G28 Y0. A0.

N285 G90

N290 M30

%

[CJep]

Another Option:

Still using the MpMaster files I've also switched the zero position for the rotary to neg X

I selected the points for the drill toolpath and make certain the points are ordered with the first point at 09:00, after all the parameters are set go o "axis control" in the "rotary axis control" set the rotation type to "3 axis" and set the rotation around Z

 

N5 G00 G17 G20 G40 G80 G90

 

N10 G91 G10 L2 P1 X0. Y0. Z0. ( G54 A0. )

 

N15 G28 Z0.

N20 T1 M06 ( 1/2 SPOTDRILL)

N25 G00 G17 G90 G54 A0. X-5.75 Y0. S1675 M03

N30 G43 H1 Z.125

N35 M08

N40 G94

N45 G99 G81 Z-.125 R.125 F16.5

N50 A-45.

N55 A-90.

N60 A-135.

N65 A-180.

N70 A-225.

N75 A-270.

N80 A-315.

N85 G80

N90 M09

N95 M05

N100 G91 G28 Z0.

N105 G28 Y0. A0.

N110 G90

N115 M30

%

[Mick]

Thanks for the replies.

 

Cjep, I will check that out. I used the same settings for my post, but it didn't output the X- at all. I will check out MpMaster, and see how that goes.

 

In the meantime, I hacked the post to output the X- correctly, but I don't like the way I did it, because it doesn't really reflect in backplot what you get posted.

[Alvaro Gil - Cimquest-inc.com]

If the bolt holes are in a repeating pattern, use the Xform tollbooth, set to rotate and select tool pane method not coordinate. This will spit out a rotation code.

[Mick]

Alvaro, the only drawback with that option is that a drill cycle is output for every angular move (major code bloat ).

 

Also, if the the bolt holes aren't in a repeating pattern, then the probelm still exists. I'm going to dig a little deeper with this