Problem with toolpaths generated for lathe part

[RndmNmbr]

I really hope I'm just missing something silly here ...

I'm using Sprut version Built 1.2 Rev 40148 (latest version from Tormach.)
I've been using sprut to do milling work for quite some time and have gotten it to do some pretty sophisticated things, so I've got reasonable working familiarity with sprutcam and it's "idiosyncratic" behavior. However, I've had no reason to use it for turned work until now.

I just started using it to generate the paths for some lathe parts and have immediately run into trouble. I've distilled the problem down to a VERY simple test part: it's a 0.750" cylinder with a 0.015" radius on the end. It was drawn in Alibre and exported as an IGES. Sprutcam seems to import with no issues.

The problem is that the paths generated do not match the part. As you can see in the screenshot, it almost acts as if the part is not parallel to the lathe axis. The finish pass cuts a taper and cuts much smaller that the actual part diameter, completely ignoring the radius on the end of the part. It actually generates a cut that goes underneath the green job assignment line.

If I export a part with a similar geometry from alibre, but with larger dimensions (3.000" diameter and a 0.750" radius) it generates the correct path. I'm just using the default tools as I'm assuming it shouldn't make much difference for this part. I figured I would generate my own tooling library once I got the hang of the application in lathe mode.

I've attached the file in case anyone wants to take a look. Am I doing something silly here? Has anyone else seen this?

[mayhugh1]

If you look a bit further down in this forum under the thread "Question for Live..." you'll see a discussion about problematic lathe toolpath generation in Sprutcam7. Over on the official Sprutcam user forum there is another thread about the same issue. Sprutcam has just released a new lathe profiling operation which hopefully should address these issues. The 7.1.3xxx release is available at their website. I was going to download it a few nights ago, but I then noticed that it still seems to be in flux and so I'm still waiting a bit longer. Basically, what I have been doing as a work-around (discussed in the threads) and has been working for me is to break up my project into two models - one for internal profiling and one for external profiling. Then when I import the models into Sprutcam, I regenerate their sections rotated several degrees from their original positions. - Terry

[MichaelHenry]

Tormach has SC7.1.3.42692 available for d/L from their FTP site. It was apprently uploaded there on 4/11. I just downloaded so can't comment o what it fixes.

Mike

[mecheng10]

I experienced a similar problem on a lathe part a while back. It turned out that Sprutcam was getting confused by some of the 3D geometry I imported. Once I projected the 3D solid onto a 2D curve and deleted the 3D geometry I was able to make it work. It does seem like a bug that needs to be fixed. Since I do all of my Cad in 3D I dont really like to have to convert to 2D - just extra unnecessary steps...

-Brian

[Live]

I really hope I'm just missing something silly here ...

I'm using Sprut version Built 1.2 Rev 40148 (latest version from Tormach.)
I've been using sprut to do milling work for quite some time and have gotten it to do some pretty sophisticated things, so I've got reasonable working familiarity with sprutcam and it's "idiosyncratic" behavior. However, I've had no reason to use it for turned work until now.

I just started using it to generate the paths for some lathe parts and have immediately run into trouble. I've distilled the problem down to a VERY simple test part: it's a 0.750" cylinder with a 0.015" radius on the end. It was drawn in Alibre and exported as an IGES. Sprutcam seems to import with no issues.

The problem is that the paths generated do not match the part. As you can see in the screenshot, it almost acts as if the part is not parallel to the lathe axis. The finish pass cuts a taper and cuts much smaller that the actual part diameter, completely ignoring the radius on the end of the part. It actually generates a cut that goes underneath the green job assignment line.

If I export a part with a similar geometry from alibre, but with larger dimensions (3.000" diameter and a 0.750" radius) it generates the correct path. I'm just using the default tools as I'm assuming it shouldn't make much difference for this part. I figured I would generate my own tooling library once I got the hang of the application in lathe mode.

I've attached the file in case anyone wants to take a look. Am I doing something silly here? Has anyone else seen this?

Hello Mr. Random Number.
It seems the problem with lathe operation in US is just because you are using the imperial measurement system. SprutCAM have not been tested a lot with imperials. Could you please attach your SprutCAM.cfg and SprutCAM.dsk files to the thread. You can find them in the \Users\{YourUserName}\AppData\Roaming\SPRUT Technology\SprutCAM\Version 7\ folder, in case you are running Windows 7.
It will help us a lot to fix the problem.

[Live]

If you look a bit further down in this forum under the thread "Question for Live..." you'll see a discussion about problematic lathe toolpath generation in Sprutcam7. Over on the official Sprutcam user forum there is another thread about the same issue. Sprutcam has just released a new lathe profiling operation which hopefully should address these issues. The 7.1.3xxx release is available at their website. I was going to download it a few nights ago, but I then noticed that it still seems to be in flux and so I'm still waiting a bit longer. Basically, what I have been doing as a work-around (discussed in the threads) and has been working for me is to break up my project into two models - one for internal profiling and one for external profiling. Then when I import the models into Sprutcam, I regenerate their sections rotated several degrees from their original positions. - Terry

I suspect all your problems are just because you have once set an incorrect digit tolerance in SprutCAM settings (3 digits instead of default 5). All you guys are trying to machine very small parts (less than 2 inches). I recommend to use digits tolerance at least 100000 times less than the size of the part. Anyway could anybody please attach a real SprutCAM.dsk and SprutCAM.cfg files from US ?

[Live]

Hello guys, here is the link to the fixed version

http://download.sprutcam.com/downloa....1.3.42918.exe

We have fixed the problem with getting intolerant lathe contour from 3d model in imperial projects (Problem with toolpaths generated for lathe part). The fix will affect only new projects because the lathe contour is cached in operations. To clear the cache in existing projects you can reassign the part in the root of the job tree (delete old one, and add it again).

And we also have fixed the annoying SprutCAM behavior when opening imperial projects. Now when you open a project it will be already zoomed. No need for wheel scrolls every time you open a project! )

[RndmNmbr]

Live,

Sorry I missed your reply - for some reason the forum stopped notifying me that the thread had traffic.

In case they are still any help to you guys, now or in the future, here are the files you requested. I'm downloading the new version to try now. Thanks for the response.

I have a bunch of lathe work coming, and they are ALL small parts!