Need Help!- 4th axis positioning is not posting correctly.

[TXFred]

I guess I should introduce myself first. I'm Frederic, and I'm an entry level CNC programmer and machinist for TXDOT.

We have a Haas VF-2 with a fourth axis, and use MasterCAM X4 for our programming.

I wrote a simple test program that should use the 4th axis for positioning. It looks good, but when I post it I get a number of errors like this one.

07 Jun 2010 07:23:21 AM - <2> - RUN TIME - - Only single-axis rotation is allowed! Angles may be incorrect.

Reviewing the gcode, the angles are incorrect. The TOP toolpath looks OK, but there is no initial A0.0 command, so the program will start wherever the rotary table was left. That's not good.

Next, the Front toolpath runs at A-90.0. That's correct.
The Bottom toolpath is at A-180.0, which is also correct.
Finally, the Back toolpath is at A-180.0, which is incorrect. It should be at A-270.0, or A90.

My best guess is that MasterCAM doesn't know how my rotary table is oriented. The Post file is correct in that regards, but maybe MasterCAM has its own setting that I don't know about.

I've attached my gcode, .err file and .mcx file. I'm sure that this problem is just due to me making a mistake, but I cannot spot the problem. If you can help out, I'd be grateful.

Cheers,
Frederic Scott

[cad01]

you say your post is right? are you sure? have you also checked your machine and control defs? I will have to wait until tomorrow to look at the file, if some one else don't jump in until then.

[Superman]

The BACK and BOTTOM default views wil be up-side-down ( out by 180° )
What the ERR file is saying is that A-axis can rotate to that view BUT there is no C-axis to spin it around to get the part orientation

You will have to define them yourself , rotate around Z to create a new view and use them in your opersations

The view created should be as seen by the tool

[TXFred]

Originally Posted by Superman The view created should be as seen by the tool

I think I follow you. I'll play around with this tomorrow and see what I can come up with.

If I get it right, I'll save a blank file with the correct views as a template. I'd like to prove that the 4th axis is useful enough to leave it set up on the machine all the time. Quickly designing and making small parts in this way would do that, and then we wouldn't have the 4th axis sitting behind the machine gathering dust all the time.

[TXFred]

Superman,

Thanks for your advice. Creating new views for the Bottom and Back with the correct orientation did the trick.

Cheers,
Fred