Face path cutting air

[jasonmtbx]

Hello, 

I'm trying to do a face on an angle with a .5" end mill, but it's cutting air pretty far away from the part. The X, A, and B axes seem to be going to the correct location, but Y and Z are off. It looks fine in the simulation, but not in the machine. I've double checked my work offset and heights and it seems to be okay. The other paths in the program seem to be fine as well. 

I've attached some pictures and the part file below:

(that extra stock on the sides isn't actually there in the part)

This is where the tool is trying to cut

[DanielMolloy]

Hi @jasonmtbx,

Is that not just the toolpaths start point? (see attached screenshot). If you run the machine past this point does it not then move down and cut the part? If not you could be running into a posting problem.

[jasonmtbx]

No, I’ve already let it run for a bit. It’s “cutting” there. Also, based on the path itself in Fusion, it should start right on the left edge of the part. I have a feeling it’s a work offset issue, I haven’t done 3+2 machining on a non-central work offset before. The offset is set to the back left corner of the part, and I don’t have DWO/TCPC. I’m going to resort to using a BEM and 3D mill it, but I would still like to figure this out for future reference.

[jasonmtbx]

Actually, I can see why you thought that. Sorry, the picture doesn't capture the depth. The tool is actually a solid few inches BEHIND the part, not only above. Should've gotten a quarter view picture, oops.

[daniel_lyall]

Are you sure the X and Y are pointing in the correct direction? it is different from the setup and other tool paths.

[jasonmtbx]

I thought about that as well, but no matter which way I had it, it was still trying to cut in the same relative location

[daniel_lyall]

Don't ask me how this happened but it is showing now that it is cutting air all I did was was do something else and came back and there it is.

I changed the bottom height to selected contours and it looks correct.

[jasonmtbx]

Interesting, but that's not where it was cutting air in the machine. It was off about 3 inches(ish) behind the part in the Y axis.

I really think it has to do with where the offset is, being that its trying to machine on an angle. Generally, I do everything with my main work offset, which is set to the point where the center of A rotation and the center of B rotation meet, and the tools are measured to where the center of the A rotation is. That way, no matter which side the part is rotated to, the tool height will be consistent, and the part will be the same as it is in Fusion. Being that this is a 5 axis machine, for most parts, I can do everything in one go except for the bottom face, and most of the time the bottom face is either just flat, or has some minor features. I've never had to do an angled face like this on a 2nd op, so that's likely the issue.

After all, I've only been programming/machining for a year now lol. Still have lots to learn.

[DanielMolloy]

Hi @jasonmtbx,

Could you post out this code for the facing and share it?

[jasonmtbx]

Sure thing

[daniel_lyall]

It is a strang one you are not the first in the last couple of weeks to have it cutting in the wrong spot.

The Center of rotation is where the WCS should be it is the default for all posts unless you have all the fancy offset avialble and or the bit of code that lets you have the WCS anywhere up to a point.

What machine is it?

What post are you using?

[jasonmtbx]

2006 Haas VF-2D with a 2008 Haas TR-160 Trunnion mounted on the bed.

Using the Haas Trunnion (Pre-NGC) post from the Post Library (https://cam.autodesk.com/posts/post.php?name=haas%20trunnion)

[DanielMolloy]

Hi @jasonmtbx,

There definitely looks like there is something scrambled in the post. Take a look at the screenshot, the Y position in fusion is being outputted as X in the post (but inverted). As for the Y, not sure where it is grabbing that from. If you could send me a screenshot of your post properties in the NCprogram I can take a look at it.

[jasonmtbx]

The properties in the NCProgram? Or the post process box where all the green text options are?

[DanielMolloy]

The properties in the NCProgram, for clarity i have attached a screenshot.

[jasonmtbx]

Ah, here you go.

[DanielMolloy]

Hi @jasonmtbx,

I will take a look and see if i cant figure it out. This might be tomorrow now as i have a rush job i need to get to!

[daniel_lyall]

There is nothing there that would make it happen.

[seth.madore]

@jasonmtbx Since you don't have DWO, can you walk us through the process of how you establish your work offset when the trunnion is rotated 30 degrees?

[DanielMolloy]

Hi @jasonmtbx,

I haven't had a chance to take a look at this yet, apologies for the delay. Its very much a case of when it rains it pours at the moment! 

Will come back to you once i have been through it.