After a run, some faces can be left without a finishing operation, or only partly finished. The usual causes are tool reach, geometry that can't be milled as modeled, settings that limit what CAM Assist finishes, and workholding in the way. This article walks through them. Unfinished faces are also called skipped faces or unmachined surfaces.
Which faces are unfinished?
In the Program stage, the summary at the top shows 1 unfinished face or the number of unfinished faces. Click it to highlight those faces in the 3D view, and click it again to hide them.
Then click Machinability feedback at the top of the stage. Many of the issues listed there name the cause and a change that would fix it. See The Program pane in the guided workflow.
Did a tool not reach, or was there no suitable tool?
The most common cause. Your libraries may have no tool long enough, small enough or with a holder slim enough to reach the face.
Machinability feedback then shows Insufficient tool stick-out, Insufficient usable tool length or Tool over-engagement, with the tool change that would help.
- Click the issue, then click a recommendation to highlight the faces it affects.
- Make the change: more stick-out, a longer usable length, or a smaller tool in your library.
- Click Run CAM Assist again.
Also check that the tools you expect are usable for this part. In the Tools stage, a tool that can't be used shows why, for example Not for this material. See Set a tool's allowed usages and stock materials and CAM Assist has no usable tools.
Can the face be milled as modeled?
Some geometry can't be cut with a rotating tool, for example a sharp internal vertical corner in a pocket. CAM Assist machines the part as modeled, so it leaves these areas.
- The Assessment stage flags surfaces no typical tool can reach as Unmachinable surface. See The guided workflow stages.
- CAM Assist won't finish an internal corner with a tool of exactly the corner's diameter unless Allow equal tool and feature radii in vertical corners is on in the configuration's Finishing tab. See Configuration settings.
Fix: model the corner radius you'd actually cut, then start CAM Assist again. Or finish that area yourself in your CAM package.
Does the face need finishing from more than one direction?
A face that blends across several levels or curves round the part may not be reachable from one direction. The Assessment stage shows Face requires splitting.
- In Autodesk Fusion, keep Automatic facet splitting on in the configuration's Finishing tab, so CAM Assist can split it.
- In other CAM packages, split the face in your CAD model, then start CAM Assist again.
See "Face requires splitting" in CAM Assist: is it safe to continue?
Was the face only partly finished?
When one tool can't finish a face completely, CAM Assist adds a - Partial operation and usually a - Rest operation to clean up. An operation ending in - Partial Rest, or a - Partial operation with no - Rest, leaves part of the face unfinished, and the face counts as unfinished. See What are Rest and Partial finishing operations?
Is the solid model damaged?
Faces CAM Assist can't read can't be machined. The Assessment stage shows Non water-tight model, Part meshing failure or Stock meshing failure.
- Repair the body in your CAD or CAM package so it's a single closed solid.
- Start CAM Assist again and check the Assessment stage.
See "Non water-tight model" or "Geometry assessment error" in CAM Assist.
Is workholding or avoidance geometry in the way?
CAM Assist keeps every tool clear of workholding and avoidance geometry. A face next to a vise jaw or clamp may not be reachable in that setup.
- In the Setups stage, check the bodies selected under Workholding and Avoidance geometry on each setup card are the ones you mean. See Select avoidance geometry and workholding.
- Machine that face in another setup, where the workholding is out of the way.
Can the setups reach the face?
A face is only finished from the directions your setups allow.
- A 3-axis setup can't finish faces on the sides or underside of the part. Add a setup, or use 3+1 or 3+2. See What are 3 Axis, 3+1 and 3+2 machining modes?
- With Select directions in a 3+2 setup, CAM Assist only uses the directions you picked. Add the direction the face needs. See Choose machining directions for a 3+2 setup.
- Check every setup you need is included (its switch is on) in the Setups stage. See Set up your setups for CAM Assist.
- For holes, see CAM Assist didn't drill, tap or ream a hole.
Did you limit what CAM Assist finishes?
These settings stop CAM Assist finishing some faces on purpose.
| Setting | Where | What to check |
|---|---|---|
| Finish full part | Setups stage > Finishing Geometry | If it's cleared, only the faces you selected are finished. Click Select faces and add the missing faces, or tick Finish full part. |
| Finishing and Undercuts | Setups stage > Toolpath Types | If Finishing is cleared, nothing is finished. Undercut features need Undercuts ticked and undercut tools in your libraries. |
| A deleted operation | Program stage | Faces from a deleted finishing operation aren't machined. See Delete a finishing operation. |
Maximum internal corner radius in the configuration's Finishing tab also affects how CAM Assist finishes internal corners. If fillets are left unfinished, check this value. See Configuration settings.
Is the face already at the stock surface?
If the stock already matches the part on a face, there's nothing to cut there. The Assessment stage shows Pre-finished surface.
If the face should be machined, your stock is too small there. Edit the stock in your CAM package so it covers the face, then start CAM Assist again.
How do I finish the faces that are left?
- Change the settings or tools above and click Run CAM Assist again.
- Program the remaining faces yourself in your CAM package after you send the program.
Still not working?
If you've checked all of the above and CAM Assist still leaves faces you think it should finish, contact CloudNC support. Include the part file, your tool library and your CAM Assist log files: see Find your CAM Assist log files.