Surfaces and Model both selected on 3D toolpath

[rickyrayjay]

I have a co-worker that used a Surface Finish Parallel on a 3D nose. I noticed that he window selected over both the model as well as his surfaces that he created (in order to remove holes). I didn't think anything of it at the moment but when he ran the toolpath in our 3-axis Doosan/Fanuc controller, the tool (ball endmill for surface operation) had a very odd step over and left scallops all through the narrow end of the part. In hind sight, I diagnosed it by viewing a backplot from right view and saw that the toolpath was jumping and stepping at the bottom edges in a not familiar way. We went back to his geometry and proved that he had both the model (unsuppressed) selected as well as his created surfaces (with suppressed holes) selected which were coincidentally one exactly on top of the other in space. We removed the model from drive geometry and just stuck with his created surfaces and it fixed his issues.  I was aware that he window selected all of it at the time and understand that is a "dirty" way of selecting surfaces/geometry to drive but was simply unaware that it would create an issue. Can anyone possibly explain the "why" it would confuse Mastercam as it did (reading 2 separate drive surfaces/model selection in the same locations in space)? If needed, I may be able to replicate it and upload a file but just hoping someone understands without having to recreate it. Much appreciated.

[JParis]

Surface normals maybe?

I like to select the  minimum amount of geometrey that I need for the cut I am creating...it helps with crunch times...

If the surface normals in areas were reversed, it would then read the solid geometry and if there are holes or openings, it may show up in the cuts..the variations could be the surface nornals then going back to the correct directions and the toolpath correcting itself on those..

Tough beyond that to really know without digging into it

 

[crazy^millman]

Surfaces have U and V direction and Solid don't. The toolpath algorithm when working with surface acts completely different than working with solids. The other issue is the tolerance at which he created his geometry. Surfaces can be jagged and not smooth at edges where with solid at joints and intersections most times will be, but not always. Many factors and other things to consider before saying what is the real issue.  .

Rule of thumb for me is never have more than one set of drive geometry for any toolpath on the same level. I have may have 10 models that have the same surfaces for features on them spread out over 10 levels, but when driving a toolpath one level for driving the toolpath is only ever visible. I need to machine 2000 surfaces on a 30000 surface part I will take the time to only select 2000 surfaces not the whole model. I find Mastercam is more stable and processes toolpath faster when I tell it only worry about what it needs to worry about. I see many lazy programmers picking whole models to machine 10 surfaces. Then you try to go back and figure out what they were thinking and what they were driving their toolpath from and is can be a nightmare.

[billb]

What happens when you create surfaces from that solid?  Do they hold their shape?

What happens if you use HST/Raster with the same geometry (solid and surfaces)?

If you duplicate the issue, please send it to [email protected].

Thanks.

[rickyrayjay]

Thanks for all of the replies. billb, yes creating surfaces from solid do hold their shape. In our case, the surfaces had holes and counterbores in them. We created the surfaces from solid, then filled holes. That runs perfectly fine. The issue was that the model and surface levels were both toggled on along with a window selection for drive surfaces which selected both the model as well as the created surfaces. Simply removing the solid from the toolpath geometry left us with only the user created surfaces as drive surfaces which works just fine. 

[AMCNitro]

23 hours ago, rickyrayjay said:

Thanks for all of the replies. billb, yes creating surfaces from solid do hold their shape. In our case, the surfaces had holes and counterbores in them. We created the surfaces from solid, then filled holes. That runs perfectly fine. The issue was that the model and surface levels were both toggled on along with a window selection for drive surfaces which selected both the model as well as the created surfaces. Simply removing the solid from the toolpath geometry left us with only the user created surfaces as drive surfaces which works just fine. 

I don't convert solids to surfaces anymore.  You can fill holes directly on the solid model, no need to convert to surfaces.  

[crazy^millman]

1 hour ago, AMCNitro said:

I don't convert solids to surfaces anymore.  You can fill holes directly on the solid model, no need to convert to surfaces.  

Yes sir me also for the most part unless I am doing some crazy millman stuff then I revert back to surfaces or even wireframe to drive a toolpath exactly like I want.

[AMCNitro]

On 2/25/2022 at 8:49 AM, crazy^millman said:

Yes sir me also for the most part unless I am doing some crazy millman stuff then I revert back to surfaces or even wireframe to drive a toolpath exactly like I want.

Same, sometimes I need to machine plastic prototypes or weird features on a mold, then I might convert to surface so I can manipulate it.   Other than that, I get the models from the engineers and program from there.