3d tool paths offset from 2d

[kesparate]

ok so i've checked all my settings about 50 times and i can't sort out what i did.
what i'm doing is milling a rectangle. (pretty straight forward so far,eh?)
then using the 3d surface finish parallel toolpath to mill a shape similar to the roof of a house on top of the rectangle with the peek running parallel to the y axis.

the probelm that i'm having is that the roof shape is shifted in x so that it has too high a wall on one side and a little bit of the radius cut into the other.

i've run the code on two machines and got the same effect so i'm ruling out the machine as the cause. are there any obvious settings i should look at?

if needed i can probably post a modified version of the part so it can be looked at. it's a micro part so the offset is really only about .002 or so, but looks gigantic.

any ideas appreciated even if your just speculating.
thanks

[Matt Berube]

Kind of hard to picture this in spite of your attempt at a detailed description.

It would be helpful to see the actual MC file with your toolpath so we can tell you what's wrong.

If you can't post the actual file then I suppose the "modified" version would be better than nothing...

Other than that I wonder if your surface geometry is accurate ?

Are there toolpath filtering tolerances set too loosely and causing this problem ?

Is your stepover small enough ?

Can you extend the surfaces a bit so the toolpath starts away from the actual part a little ?

I could go on and on...

[Superman]

You may have problems using the containment, start off with minimum info and then add features to restrict the toolpath
(ie. modify the boundary and to use "outside" and a negative value - if you need it )

also cut from both sides and allow Z positive ON

HINT: for awkward shapes and to get the tool to drop in outside your stock instead of plunging at the edge of the shape, create a surface ( size of stock) below your machining area for mastercam to "fudge" the drop-in points ( you may have to play with the "Cut depths" settings)

[kesparate]

ok having some trouble uploading so if anyone wold like me to send them the file i will be happy too. i'll try attaching it again later as well

i had to strip it down so it would zip up small enough, and still it's giving me crap
that actual part is these toolpaths plus the transforms needed to make a total of ten forms on the block.
the material is 110 copper and the tools are all micrograin uncoated carbide.
i've cranked all the tolerances way up and you'll see that the step over is so small it's almost ridiculous.
at this point i'm officially holding my breath and crossing my fingers that i've missed something. any help would be excellent.

[Shotout]

Originally Posted by kesparate ok having some trouble uploading so if anyone wold like me to send them the file i will be happy too. i'll try attaching it again later as well<snip> at this point i'm officially holding my breath and crossing my fingers that i've missed something. any help would be excellent.

You have checked that the normal side of your surface is on the same side as your tool plane right? On something in the micro scale it would be possible to miss it. It kind of sounds like the good surface normal side is correct but the other is flipped. It would cause an over cut of a otherwise clean surface will a well defined toolpath.

In the X versions use the edit menu and select Change Normal. Without clicking on the surface bring your cursor over it so it auto highlights and make sure the arrow points up (Z+). If not then it is trying to cut the wrong side of the surface. You'll probably need to rotate the view some to see the arrow. If you can't see it at all select the wireframe view and again move your cursor over the surface and see if it is pointing down (Z-)

[kesparate]

good thought.
i have checked the normals and they all seem to go the correct way. it is pretty easy to miss stuff like that on micro parts for sure.