CAM ToolShape

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Revision as of 13:56, 15 April 2022 by Roy 043 (talk | contribs) (Usage...)
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Description

ToolShapes are a core part of the Path Tools system. ToolShapes are the templates from which ToolBits are created. They represent the specific physical shape of a tool. A ToolShape does not completely describe the bit - for that some additional parameters are needed which will be added when an actual bit is parameterized from the template.

Initially ToolShapes are just FreeCAD documents with a single Body created from the Part Design workbench.

Creating new ToolShapes is an advanced topic. The most commonly needed ToolShapes already exist and are provided with the FreeCAD installation at:

  • On Linux it is usually /usr/lib64/FreeCAD/Mod/Path/Tools/Shape
  • On Windows it is usually C:\Program Files\FreeCAD\Mod\Path\Tools\Shape
  • On macOS it is usually /Applications/FreeCAD/Mod/Path/Tools/Shape

They are:

ballend.fcstd
bullnose.fcstd
chamfer.fcstd
drill.fcstd
endmill.fcstd
probe.fcstd
slittingsaw.fcstd
thread-mill.fcstd
v-bit.fcstd

These can be found in the /Mod/Path/Tools/Shape/ subdirectory where FreeCAD was installed.

Usage

  1. Create a new FreeCAD document.
  2. Open the PartDesign Workbench.
  3. Create a Body and give the Body a label you want to show up in the bit selection.
  4. Create a Sketch on the XZ plane and draw half the profile of the bit.
  5. Constrain the bottom most center of the bit on the origin (0,0). This will be the center of the axis on which the G-code will rotate the bit.
    • Note: Do not add dimensional constraints at this time.
  6. Close the Sketch.
  7. Revolve the Sketch around the vertical Sketch axis.
  8. Open the Path Workbench.
  9. Select the Sketch in the Tree view. This ensures that the PropertyBag created in the next step will be nested in the Body.
  10. Select the Path → Utils → PropertyBag option from the menu.
  11. A PropertyBag named Attributes is created. This PropertyBag will control the variables in the Sketch.
  12. Double-click the PropertyBag in the Tree view.
  13. The Property Bag task panel opens.
  14. Click the Add... button.
  15. The Create Property dialog opens.
  16. Create a property named Diameter. This property is mandatory for Toolbits. Property names are case-sensitive and may not contain spaces.
  17. Select Shape from the Group dropdown list.
  18. Select the appropriate Type.
  19. Optionally specify a ToolTip.
  20. Click the OK button.
  21. In the Property Bag enter a value for the Diameter property.
  22. Similarly add all other required properties.
  23. Click the OK button in the Property Bag task panel when done.
  24. Double-click the Sketch in the Tree view.
  25. Add dimensional constraints using the properties from the created PropertyBag.



    • Select a feature such as a line, arc or points in the drawing. Assign a length, radius, dimension etc to the feature as to apply a constraint.
    • When assigning a value to the feature, click on the little round blue circle instead of entering the value directly. This is where you can invoke the attributes assigned to your recently created PropertyBag.
    • A formula Editor will open and type in in the following: "<<Attributes>>.Diameter" (or your appropriate variable name) and hit the "OK" button.
    • The Length field will be greyed out indicating that the field is a fixed constraint in the Attributed Property Bag. Also, the constrained dimensions will be colored Orange indicating that the parameters are kept in an external Property Bag.
    • Repeat the above constraint assignment procedure above until the Sketch is fully constrained.
  1. Save the file as a *.FCStd file where Freecad expects to find ToolBit Shape files. By default, it is in C://Program Files/Freecad 0.19) >Mod>Path>Tools>Shape in Windows 10.
    • EndNote 1. If you are denied access to this file in Windows, start FreeCad in ADMINISTRATOR mode and it will allow access to the folder. You are finally done! Use this new custom built ToolShape in the normal fashion in addition to the standard ToolBits using the PATH workbench.
    • EndNote 2. The BODY of the Toolbit MUST be listed FIRST in the Combo View FileTree hierarchical structure. These instructions will produce this important structural order to create a successful ToolBit Shape.

Tool Thumbnail Images

Toolbits will have a small icon image of the tool in the tree if the image is saved with thumbnails active.

Important notes:

  • Before saving the document make sure you have Save Thumbnail selected, and Add program logo deselected in FreeCAD's preferences.
  • Also make sure to switch to Front View and Fit content to screen
  • Whatever you see when saving the document will end up being the visual representation of the template

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