forcing a rotary 90 deg. move in 3+2

[Zoober]

I have gotten around this in the past by hand editing, but need to know if I can do this.

We do a lot of large work, and run into limit problems doing 5 axis or 3+2 work.

 

In the first pic below, I am machining the purple tower at B0C0. Problem is obvious. The tower is too close to the pallet. Can't get there. At B0C180, I run out of Y travel. So I want to do at C90 or C270

 

I want to force the post to move C axis to 90 (plus or minus doesn't matter). I have tried bias and different planes, but It will only put C axis at 0 or 180.

Is there something I'm missing to "FORCE" a B0C90 or a B0C270 rotation??

 

TIA

 

 

This is what I want. And yes, I have tried a plane exactly like this. Still B0C0 or B0C180, depending on my bias settings.

[DavidB]

Can you use the linear limits in the post.

code:

---

 #When the tool repositions, an intersection is made to the limits and the

#tool is driven around the limits to the reposition point as required.

#Z upper limit is used as the safe transition boundary

#Linear limits relative to machine base coordinates / part origin

use_stck_typ : 0 #0=Off, 1=Stock def., 2=Limits

up_x_lin_lim : 250. #X axis limit in positive direction

up_y_lin_lim : 250. #Y axis limit in positive direction

up_z_lin_lim : 250. #Z axis limit in positive direction

lw_x_lin_lim : -250.#X axis limit in negative direction

lw_y_lin_lim : -250.#Y axis limit in negative direction

lw_z_lin_lim : -5. #Z axis limit in negative direction

---

So in your case if the Y-axis travels to low it will rotate the C-axis.

[Guest CNC Apps Guy 1]

Yeah, get a Matsuura and CAMplete!

[Zoober]

Tried that David. It still only goes 0 or 180 depending on my bias settings. I've tried it in the past, with these settings, but no go.

This tower is at Y-22.090

Here is my settings:

code:

---

 #When the tool repositions, an intersection is made to the limits and the

#tool is driven around the limits to the reposition point as required.

#Z upper limit is used as the safe transition boundary

#Linear limits relative to machine base coordinates / part origin

use_stck_typ : 2 #0=Off, 1=Stock def., 2=Limits

up_x_lin_lim : 250. #X axis limit in positive direction

up_y_lin_lim : 22. #Y axis limit in positive direction

up_z_lin_lim : 250. #Z axis limit in positive direction

lw_x_lin_lim : -250.#X axis limit in negative direction

lw_y_lin_lim : -22.#Y axis limit in negative direction

lw_z_lin_lim : -5. #Z axis limit in negative direction

---

James, I'm not ready to trade this Niigata just yet....

[Guest CNC Apps Guy 1]

Nigata... Rubbish... j/k

 

In case you do change your mind though, you know where to find us!

[Zoober]

[crazy^millman]

Robert, I have had all types of problems with Mastercam giving me a fit with C-planes. Sometime I have to go to ISO making sure I am in Top. Then Changing the C-planes and this will most times take care of that index problem.

[Zoober]

Ron, I don't think that it is planes, because I can make it do everything else right.

Theoretically, there are unlimited possibilities at B0C__.

I think it is tied up in the locked area of the post, because of the "2 possibilities" for the vector control in 5 axis math. More choices may mean calculating too many vectors and slowing post processing for something not often done.

That's my thinking. Maybe one of CNC or IH post maniacs will pipe in.

[crazy^millman]

Add a force using a Misc integer. Anything locked up is off limits even if it is broke so good luck on that quest.

[Zoober]

I've tried all the bias and pos/neg primary and secondary settings. Only two places it will go is C0 and C180. Both out of limits.

[DavidB]

Have you tried this at 90?

 

code:

---

 # mi5 - Start initial secondary rotary axis bias

# +/-999 represents start as close to limit as possible

# 0 represents calculate without using bias

# Any other value represents an angle in degrees to attempt

# to position near.

# -999 = Low, 0 = Off/Default, 999 = Hi, Value = Angle bias

---

[Zoober]

Yes David, I have tried all of the bias settings and Mi's. All I get are C0 and C180.

I have resorted to a xform rotate of the path, and then manually editing the C position.

Sure wish I could force a C90.

Can anyone try it to see if they can get a forced C90?

[MLS]

In the past if I ever wanted to force something similar I would have to do it with the toolpath. Now that I know more about the post we are using I could do it in there, unfortunately it isn't a Mastercam post. It would be a nasty macro I imagine too.

 

The dirty workaround...

Skew your drive geometry a tiny amount in the orientation that will force a B .001 movement and drive it with a multiaxis toolpath?

[Zoober]

I actually tried the dirty trick, but because it is so far off CL, that even the smallest skew makes it not square enough. This is for a God tower to probe, and needs to be dead nuts.

For less accurate or smaller stuff, that works pretty good.

[MIL-TFP-41]

In my pre-CamPlete days, I used to do a "dummy" operation before the op that I needed the orientation to be correct....as in do a point toolpath on an A-10. C90 plane (or in your Horiz case, B-10 C90)...MPGEN5AX will then follow that orientation (the c90) for the next toolpath.

 

Downside is now you got an extra move that is not needed...but it will get you to where you want to go.

 

Also, for this to work (I am guessing you are using MPGEN5AX) this must be set to zero

code:

---

#Force rotary axis reset at toolchange and other options

frc_cinit : 0

---

[Zoober]

That sounds better than having hand edits. Thanks JMC I'll give it a go next time around.

[Josh T™]

quote:

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Yeah, get a Matsuura and CAMplete!

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