Rotary Axis Moves

[PBoulanger]

Hi everyone out there in Mastercamland. I hope someone can help me with a problem I'm having with the way MC mill v.7.2c and the generic MPFAN post processor output rotary axis moves.

I need to have the angles post out in one direction only, and not flip between positive and negative angles depending on the size of the angular move.

The post is set for rotation about the x-axis with positive angles in the CCW direction. I created a small test program to generate toolpaths at A=0, 90, 180, 270, 45 & 315 deg.s, in that order. When posted the code generates A=0, 90, 180, 270, 45 & -45 deg. moves. It's the last -45 deg. move I can't live with. I would like the post to generate A315 for the last move or A405, (360+45), and A675, (360+315), for the last two moves, the windup effect.

I've tried playing with the post processor's switches and variables but to no success. Anyone out there have any suggestions.

[Allan Brown]

In the V7 era Mpfan, you would have to check the cdelta variable to make sure you are always moving in +ive A. I would make these changes as a starting point:

 

code:

---

ctol : 360 #Tolerance in deg. before rev flag changes

 

#Rotary axis revolution calculation

pcoutrev2 #Add or subtract 360 degree for position

if cdelta > zero, rev = rev + one

else, rev = rev + one

 

pcoutrev1 #If motion exceeds ctol, add wind-up

if abs(cdelta) > ctol | cdelta < zero, pcoutrev2

 

pcoutrev #Modify for wind-up

cdelta = csav - prv_csav

pcoutrev1

cabs = rev * 360 + csav

!csav

---

[This message has been edited by Dave Thomson (edited 11-20-2000).]

[PBoulanger]

Dave;

Thanks for the response. I haven't had much time to work on this problem since I wrote my initial query, but a simple test of your solution, (with typo in pcoutrev2 postblock corrected), did provide the desired results. I just have to make sure it doesn't effect how 4-axis surface milling toolpaths are posted which require constant direction changes in the A-axis or how to set up the post to limit A-axis moves to a set range, ie: -90 to +90 deg.

Thanks again for your help.

Peter