G55 changing?

[Randy Morton @ Clem Industrial]

Hey,

 

I was running our Horizontal today, machining a casting on 3 sides (rotary axis and all that). Side 1 = G54, Side 2 = G55, Side 3 = G56

 

I set them all up and kinda went for it. Side 1 is all good. No problems at all (doing same op on all sides, face, drill, cbore, tap). On side 2 and 3 the offset? seems to be changing. I got side 1,2&3 all faced good, when it came to drill, s1 drilled fine, s2 the drill was out 3 and some odd inches, same with side 3.

 

WTF? Adjust my offset (a little baffled at this point) and go again. Drills all good. Goes to cbore and that tool is out too, but only on side 2 & 3. Side 1 is fine. What the frick is going on?!?!?!

 

Obviously since side 1 is running fine, it's not the tool length offsets that are out. Oh yeah, and the direction I had to offset was Z + every time (every tool!) from side 2 + 3....

 

HELP! Please...I am so confubulated...

[Randy Morton @ Clem Industrial]

bump

[DavidB]

It sounds like your rotaion point does not match you WCS.

Why use three WCS when machinig one component?

 

G54 = Centre of rotation then to machine right and left sides of the casting just use Right and Left C,T/Planes.

[Tim Simmermon]

Randy,

 

Post your NC file to the FTP or at least one of the tools that you are having a problem with (Say Drill 2 on the G56 side). Maybe looking at it will ring a bell.

[88Matt]

I have to agree with Dave. Why are u using multiple WCS's with a rotary motion? Are u doing multiple parts and a tombstone or just one? If its an A axis on a VMC, set ur Y&Z to centerline of rotation and then put X wherever u want. Let MC do the rest.

[Tim Pruett]

I had this happen to me once but I wasn't using the rotary table. A couple of my programs jumped over 1". Look in your planes box on the toolpath parameters page and make sure x y and z filds are at 0. If you enter anything in these fields it offsets your work offset that much. HTH

[kinglouie V]

if you set your options in misc. as 1st offset 'G54' and then set subs to 4 you might get what you want if you set your rotary up in the 'Z' axis. This may not be totally correct but seems like a good place to start other than WCS.

[Randy Morton @ Clem Industrial]

I wish I could post a file, but due to the company privacy policy on their pumps I cannot.

 

The reason I went with multiple WCS's is that is how I was show to do such a part. It does not have a center that I can easily reference from on my horizontal due to it actually being a casting.

 

I am still not convinced that it is a MCX error, but rather a machine error. I checked what you said Tim, and everything seems to be in order of where and what I want for planes...

 

I am stumped. Oh well. It was just an R&D job. If we actually get into production of these, I will look more carefully at my MCX file or the machine to figure exactly where the problem lies.

 

Thanks for the feedback!

[DavidB]

The way I run my horizontal machines is the centre of machine rotation is X,Y,Z zero.

The post rotates from there.

Roatation is done from C and T/planes

[crazy^millman]

IMHO the only way to do Multiaxis work.

[Bruce Caulley]

Randy, Had a similar problem on a 5 axis machine last week. Check to see that you don't have an active G91 anywhere. I had :

 

G91

G28 Z0

G00 A B

XYZ....

 

As you can see there needed to be a G90 after the G28 line. This sounds exactly like your situation.

 

Bruce

[Bruce Caulley]

quote:

---

IMHO the only way to do Multiaxis work.

---

Unless you are lucky enough to have a machine that uses dynamic compensation.

 

Bruce

[Brutus2279]

DID YOU SET WCS'S IN MASTERCAM X FOR ALL THREE OPS? IF SO CHECK THE PARAMETERS FOR THE TOOLS ACTING UP, IN THE PLANES MAKE SURE ALL THREE HAVE SAME WCS #S