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IDProjectCategoryView StatusLast Update
0004096Path[FreeCAD] Bugpublic2019-08-23 21:17
ReporterfremanAssigned To 
PrioritynormalSeveritymajorReproducibilityalways
Status newResolutionopen 
Product Version[FreeCAD] 0.19 
Target VersionFixed in Version 
Summary0004096: Material allowance does not seem to differentiate between air or unused stock and remaining parts of the model.
DescriptionFace milling path tool does not clean the face, it leaves residual bits in the corners. Using "material allowance" can extend this but it will eat into other parts of the model if it is not simply the top surface of the workpiece.

https://forum.freecadweb.org/viewtopic.php?f=15&t=38609

I see two principal issue here:
1. Material allowance does not seem to differentiate between air or unused stock and remaining parts of the model, meaning it will happily remove part of the work piece. I would consider that a serious bug.
2. A facing operation by default does not clear the selected face and thus does not fulfil its primary task in any situation. It requires a specific option parameter to be set by the user to clear the corners even if there is nothing but air/stock outside the boundary. Once the above issue is resolved , this could probably be handled in a more helpful way, overstepping by the tool radius where it does not damage the surrounding part. Material allowance could then be used to set more over step if desired to get a cleaner finish ( no turns on the work ).

If there is a step in the model, this requires some rather imaginative and ugly workarounds to clear a face, while there are obvious tools paths to achieve the result.
 
https://forum.freecadweb.org/download/file.php?id=90043

Steps To ReproduceOpen the linked FreeCAD model and look at the face mill operations. Run the sim. and note that path never goes beyond the boundary of the face. Add a "material allowance" of half tool radius to clean up and note that it takes a chunk out of the central block of the work.

PS. Ratonlaveur notes that this is not what "material allowance" usually refers in conventional machining language. This should probably be changed so that FreeCAD is not defining a new use of standard terms.

Additional Information
OS: Linux (LXDE/LXDE)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.16988 (Git)
Build type: Unknown
Branch: master
Hash: ff7975291d33a88e6a8282b88a62dbcbcc01ba2b
Python version: 2.7.15
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedKingdom (en_GB)
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Issue History

Date Modified Username Field Change
2019-08-23 21:17 freman New Issue