Preview and finished project not the same

[TimSchubach]

I teach Industrial Arts at a local high school, and my department head recently bought an STL file of a sailing ship to use as part of a project he's working on for a friend of his. We imported the file, generated the tool paths, and looked at the preview which looked OK to us. So we went ahead and ran both the rough and final tool paths. I could tell before the rough cut finished that something wasn't right. There were areas around the crow's nest that you can see in the attached photo where stock should have been removed that was not. Despite that, we ran the final tool path, which most definitely should have removed that stock, but didn't. He's using a 0.25" end mill for the rough cut, and a 0.25mm tapered ball nose for the final cut. The blank is still on the machine, so we can rerun tool paths again once we determine what went wrong.

We've also regenerated tool paths on another machine, compared the size of the gcode files, and they are exactly the same.

I uploaded both the STL we're using and the Aspire file to a OneDrive line here: https://1drv.ms/u/s!Ai2G_TPTNBp32QYbyMv ... S?e=xnlwxN

If anyone has any pointers or can tell us what might have cause this, we'd appreciate the feedback.

Thanks!

[mtylerfl]

Hi Tim,

Try adding a Zero Plane to the project, then recalculate your Toolpaths.

The Zero Plane should resolve the problem of leaving the interior material areas.

[mtylerfl]

Hmmm. Upon re-reading your post, I realize you said the Preview was correct. So I’m not sure my suggestion regarding adding a Zero Plane is a valid one after all.

[ohiolyons]

Don't use material boundary use model boundary.

Negative boundary offsets won't allow the whole model to be carved either.

[ohiolyons]

This is the second project brought to my attention that used material boundary and there has been an issue with the software acting wonky.

[ohiolyons]

Also the STL is a glb how did you import it?

Aspire can't see the file.

It looks like there is an importing issue also, the image is sitting down "inside" the material and only the top shows as on the top.

[adze_cnc]

GLB format: info

A GLB file (.glb), which stands for “GL Transmission Format Binary file”, is a standardized file format used to share 3D data.

As it was only created in 2015 I wonder about "standardized"...

[RalphPitz]

Try maching the areas in red to a flat bottom depth. Those areas are not part of the model.

[dealguy11]

Ralph has hit it. The flat areas are not actually a part of the model and as a result are undefined for machining using either the 3d roughing or finishing toolpaths. You either need to define those parts of the model, using a zero plane, or get rid of the material in those areas using pocket toolpaths. Note - the preview did not look ok when I previewed the file.

As John has pointed out, a portion of the model is below the modeling plane, probably because it was set to "center" during import. Add a base height of .689" (half the thickness of the component), then bake the component. It will no longer be buried under the modeling plane, and adding a zero plane will allow the carving toolpaths clear out the empty space.

Final note - if it were me doing this carving, I'd probably choose to pocket away all the material outside the ship rather than carve it, as it will go much faster. The open areas inside the ship's rigging could be pocketed, but are probably better done with carving paths.

[TimSchubach]

Also the STL is a glb how did you import it?

Aspire can't see the file.

It looks like there is an importing issue also, the image is sitting down "inside" the material and only the top shows as on the top.

boat2.jpg

It actually IS an STL file. Can't explain why the extension was changed to GLB as it was copied around our network.

[TimSchubach]

Ralph has hit it. The flat areas are not actually a part of the model and as a result are undefined for machining using either the 3d roughing or finishing toolpaths. You either need to define those parts of the model, using a zero plane, or get rid of the material in those areas using pocket toolpaths. Note - the preview did not look ok when I previewed the file.

As John has pointed out, a portion of the model is below the modeling plane, probably because it was set to "center" during import. Add a base height of .689" (half the thickness of the component), then bake the component. It will no longer be buried under the modeling plane, and adding a zero plane will allow the carving toolpaths clear out the empty space.

Final note - if it were me doing this carving, I'd probably choose to pocket away all the material outside the ship rather than carve it, as it will go much faster. The open areas inside the ship's rigging could be pocketed, but are probably better done with carving paths.

That makes sense. We'll give it another try tomorrow. Thanks!

[adze_cnc]

It actually IS an STL file. Can't explain why the extension was changed to GLB as it was copied around our network.

I downloaded it. I changed the extension to STL and tried to load it into Rhino 3D. It couldn’t find any valid STL entities:
 

 
I tried to import it into VCarve and it flat out wouldn’t load:
 

 
You may have an STL file somewhere but “ship.glb” ain’t it.

[ohiolyons]

i even just changed the extension and the icon changed, but Aspire couldn't see it.