4th Axis rotating to wrong point?

[McLaren]

Good morning everyone. Hopefully someone can shed some light on a problem I'm having. I'm trying to chamfer a slot on a 4th axis (Fanuc 180is control) and the machine wants to make A- moves as degrees past 360. For example:

 

X-3.7577A113.

X-3.6837A114.

X-3.4732A-113.

 

The first move is clockwise, the second move is clockwise an additional degree, and the third move is counterclockwise 227 degrees. What I believe should happen is it should be a counterclockwise move of 1 degree, at least that's how the Fadal works. Any ideas?

 

Thanks in advance for any and all replies.

[mayday]

It's probably set to shortest distance for your rotory setting

[McLaren]

I mean it considers "A" negative moves as counterclockwise distance from A0, so imagine a sample program:

G1G90A0

A50

A75

A74

A-50

A-49

 

What it is currently doing in absolute A axis positions is:

A0

CW to A50

CW to A75

CW to A74(All the way around the horn)

CCW to A310

CCW to A311(All the way around the horn)

 

What it should be doing is:

A0

CW to A50

CW to A75

CW to A74(All the way around the horn)

CCW to A50

CCW to A49(Just move 1 degree)

 

 

(Opps, just to clarify clockwise and counterclockwise are referring to tool motion, not actual 4th rotation direction, i.e. to get a clock face from noon to 3 is a clockwise rotation.)

[McLaren]

Anyone else have any thoughts?

[Greg Williams]

You need a direction M code M15/M16?

[McLaren]

I tried M15/M16 but no change. Thanks for the try though. I appreciate it.

[Guest]

McLaren,

 

What post are you using?

[McLaren]

Default MPFAN, but since the M15/M16 didn't do anything it must be a machine parameter issue right?

[Guest]

There are 2 standard fadal generic posts included with X4, why not try those instead of an MPFAN?

[McLaren]

Opps, sorry for the confusion. The problem is on a Fanuc 180is controller. The Fadal comment was for reference. I was expecting the Fanuc to operate like the Fadal.

[Guest]

ON a Fanuc the rotational direction codes are different

 

# Table rotation direction, index

sindx_cw : "M22" #Rotate CW code

sindx_ccw : "M21" #Rotate CCW code

sindx_mc : "" #Target string

 

fstrsel sindx_cw indx_mc sindx_mc 2 -1

[McLaren]

No dice. M22/M21 in my sample program didn't change rotation on the first move, and it just sat on that line waiting for a finished signal.

 

Thanks for trying anyways, I appreciate it.