MasterCam and SW

We had occasion to use Caxis milling today and found that the machine
did not replicate the SW geometry very well. We were milling a slot
for a bayonet type attachment and found that the tool did not travel
circumferentially as far as SW said it should. We ran the SW native
file through MasterCam and then to a Haas lathe.

 

P.

Haas makes a multi axis lathe ???? didn't know that.

I've been using MC with SW files for 8 years. "C" axis milling on a lathe is
the same as "A" axis mapping (axis substitution) on a mill. I've done quite
a bit of that on my Fadal VMC. I can assure you that the problem is not
geometry related

The problem could be, program set up parameters in MC, and/or post processor
output. Or it could simply be cutter comp. Is the total linear error equal
to the diameter of the tool ???

Regards

Mark

 

As a matter of fact it seemed like it was about equal to the tool radius.
Slot widths and other features were allright.

Well it has HAAS on the outside. The live tooling was not HAAS made.

 

P.

You said it was a bayonet (cam lock) type features, so.. I guess it has a
slot that runs parallel to the axis with an off shoot to the side ? I'm
guessing it's the length of the off shoot that's incorrect.

There are two ways of programming A/C axis features in MC. One is to program
the 3 dimensional curve directly. The other (and the most accurate for cams
and such) is to use axis substitution (mapping). You do this by unwraping
the curves onto a plane that lies on the center line of the cylinder. The
profiles are programmed using standard 2-1/2 axis tecniques, with additional
parameters for a rotary axis. This produces a G107 code on the Haas.

The most important parameter is the workpiece diameter. If the diameter was
entered wrong, the features running lengthwise on the cylinder can be
correct, while the features running around the outside will be wrong. If the
feature is to long the programmed diameter was bigger than the workpiece and
vise-versa.

I'm really just guessing here, but if you can send the Mastercam file to me
I can probably help. If you send it to I'll get it at work
tomorrow. My NG return address is fake

Regards

Mark