Fixing an STL file

[stevehuckss396]

I have 2 STL files that look great until i try to waterline them and get multiple open poly errors. Obviously the tool path reneration does not go well as you can see. It goes well until the 6 or 7 layer and then starts to cut closer to the boss eating material it shouldn't be.

Is there a way to fix? open poly's. Tried to change settings in my drawing program. I tried opening in Freecad and exporting. I tried online fixers but they degraded the quality to an unuseable level. Not sure what to try now. Are there any work arounds or opimizations that cambam can do to work with this problem? Think I already know the answer but thought i would ask. 

[Bob La Londe]

Sometimes I can "force it" if I change the increment levels.  Either by changing the depth increment or by changing the stock surface. 

I know that's not the clean fix you want, but sometimes I have so much work invested in a mesh that going back to blank page and starting over is like a kick in the stomach. 

Often waterline chokes on stuff that works fine with horizontal or vertical too. 

If you are using the waterline for roughing you might also try taking silhouettes at your depth increment and using those to perform 2D operations. 

If all else fails you can start over making sure to do clean booleans so you have a single watertight structure, and run a "clean" or "Simplify" operation on your source geometry before exporting the STL. 

If you are working with an STL created by somebody else there is not telling how much garbage there is inside of it.  It might not be salvageable. 

[dh42]

Hello

As said BoB, changing a little the settings for depth increment can sometimes do the trick.

The "open poly errors" can also be removed (sometimes) by changing the stepover or the tool diameter ; it appears when segments in the toolpath are very small compared to the tool diameter.

Also, sometimes, errors appears if the target depth is deeper than the bottom of the 3D model.

++
David

[stevehuckss396]

1 - Sometimes I can "force it" if I change the increment levels.  Either by changing the depth increment or by changing the stock surface. 

I know that's not the clean fix you want, but sometimes I have so much work invested in a mesh that going back to blank page and starting over is like a kick in the stomach. 

2 - Often waterline chokes on stuff that works fine with horizontal or vertical too. 

3 - If you are using the waterline for roughing you might also try taking silhouettes at your depth increment and using those to perform 2D operations. 

4 - If all else fails you can start over making sure to do clean booleans so you have a single watertight structure, and run a "clean" or "Simplify" operation on your source geometry before exporting the STL. 

If you are working with an STL created by somebody else there is not telling how much garbage there is inside of it.  It might not be salvageable.

1 - Yes I have played the "depth increment" game before and will probably have to this time.

2 - Yep! I plan to finish with a horizontal and that tool pathing looks perfect.

3 - I thought about that but every corner inside and outside has fillets or radii

4 - Yeah I don't know what 75% of that means. I don't think Alibre has a simplify or clean funtion.

5 - It is my own STL made by Alibre. I have removed all internals. Other than the surface I want to machine it is a solid mass.

I'm going to try to play with the levels and see what happens. Thanks

[dh42]

Hello

If you want, you can share your STL (and CB file) and I'll try to do the same as here
https://cambamcnc.com/forum/index.php?topic=10327.msg77414#msg77414

Is Alibre a solid modeler (like Solidworks or FreeCAD) or a mesh modeler.

If it is a solid modeler, you can also try to export the model to STEP format and I can try to convert solid to mesh from Solidworks, generally it give very clean meshes.

++
David