cross_gear_creator.py

# This script creates ABENICS (half of) cross gear in FreeCAD
import FreeCAD as App
import Part
import InvoluteGearFeature

doc = App.ActiveDocument
mod = 2.0 # gear tooth module
monopole_teeth = 12 # number of teeth
cross_teeth = monopole_teeth * 2
height = 20 # height of the monopole gear

rev_radius = cross_teeth * mod * 3.0  / 4.0 # radius for tool movement during cutting the monopole gear
monopole_base = Part.makeCylinder((mod * (monopole_teeth + 2) / 2) , height / 2)
tool_inv = doc.getObject('tool_inv')
if not tool_inv:
    tool_inv = InvoluteGearFeature.makeInvoluteGear('tool_inv')

tool_inv.NumberOfTeeth = cross_teeth
tool_inv.Modules = mod
tool_inv.HighPrecision = False # Otherwise boolean will fail
doc.recompute()
tool_inv.ViewObject.Visibility = False
fill_inv = Part.Face(tool_inv.Shape)

box_w = (cross_teeth + 3) * mod
box_h = (cross_teeth + 3) * mod / 2
common_box = Part.makeBox(box_w, box_h, 2)
common_box.translate(App.Vector(0, 0, -1))
half_inv = fill_inv.common(common_box)
half_inv_rot = half_inv.copy()
half_inv_rot.rotate(App.Vector(0, 0, 0), App.Vector(0, 0, 1), 90)
half_inv_rot.rotate(App.Vector(0, 0, 0), App.Vector(0, 1, 0), 180)
cross_quarter = half_inv.revolve(App.Vector(0 ,0 ,0), App.Vector(1, 0, 0), 90)
cross_quarter_rot = half_inv_rot.revolve(App.Vector(0 ,0 ,0), App.Vector(0, 1, 0), -90)

# Part.show(cross_quarter)
# Part.show(cross_quarter_rot)
common = cross_quarter.common(cross_quarter_rot)
mirr = common.mirror(App.Vector(0, 0, 0), App.Vector(0, 0, 1))
fuse = common.fuse(mirr)
mirr = fuse.mirror(App.Vector(0, 0, 0), App.Vector(0, 1, 0))
half_gear = fuse.fuse(mirr)
half_gear_refined = half_gear.removeSplitter() # Refine
half_gear_obj = Part.show(half_gear_refined)
half_gear_obj.Label = 'Cross gear (half)'

monopole_gear_creator.py

# This script creates ABENICS monopole gear in FreeCAD
import FreeCAD as App
import Part
import InvoluteGearFeature

doc = App.ActiveDocument
step = 5 # angle step size for tool rotation, setting low value increases computation time a lot
mod = 2.0 # gear tooth module
monopole_teeth = 12 # number of teeth
cross_teeth = monopole_teeth * 2
height = 20 # height of the monopole gear
base_corr = 0.8 # increases base shape diameter
use_FCGears = False # requires https://github.com/looooo/freecad.gears addon, set True if the addon is installed
backlash = 0.3 # only available if use_FCGears set True

rev_radius = cross_teeth * mod * 3.0  / 4.0 # radius for tool movement during cutting the monopole gear
monopole_base = Part.makeCylinder((mod * (monopole_teeth + 2 + base_corr) / 2) , height / 2)

box_w = (cross_teeth + 3) * mod
box_h = (cross_teeth + 3) * mod / 2

if use_FCGears:
    tool_gear = doc.getObject('tool_gear')
    if not tool_gear:
        import freecad.gears.commands
        tool_gear = freecad.gears.commands.CreateInvoluteGear.create()

    tool_gear.teeth = cross_teeth
    tool_gear.module = mod
    tool_gear.backlash = backlash
    tool_gear.reversed_backlash = True
    doc.recompute()
    common_plane = Part.makePlane(box_w, box_h)
    common_plane.translate(App.Vector(-box_w / 2, -box_h, 0))
    tool_gear.Placement.translate(App.Vector(0, 0, -1))
    half_inv = tool_gear.Shape.common(common_plane)
    tool_gear.ViewObject.Visibility = False
    FreeCADGui.updateGui()

if not use_FCGears: # workaround for strange if/else sytax error
    tool_inv = doc.getObject('tool_inv')
    if not tool_inv:
        tool_inv = InvoluteGearFeature.makeInvoluteGear('tool_inv')

    tool_inv.NumberOfTeeth = cross_teeth
    tool_inv.Modules = mod
    doc.recompute()
    tool_inv.ViewObject.Visibility = False
    fill_inv = Part.Face(tool_inv.Shape)
    cut_box = Part.makeBox(box_w, box_h, 2)
    cut_box.translate(App.Vector(-box_w / 2, 0, -1))
    half_inv = fill_inv.cut(cut_box)

tool = half_inv.revolve(App.Vector(0, 0, 0), App.Vector(1, 0, 0), 360)

monopole_obj = Part.show(monopole_base)
monopole_obj.Label = 'Monopole Gear'

angle = 0
while angle < 360:
    tool.translate(App.Vector(rev_radius, 0 , 0))
    tool.rotate(App.Vector(0, 0, 0),App.Vector(0, 0, 1), angle)
    tool.rotate(tool.Placement.Base,App.Vector(0, 0, 1), 0.5 * angle)
    base_shape = monopole_obj.Shape
    base_shape = base_shape.cut(tool)
    monopole_obj.Shape = base_shape
    doc.recompute()
    FreeCADGui.updateGui()
    angle = angle + step
    tool.Placement = App.Placement(App.Vector(0, 0, 0),App.Rotation(App.Vector(0, 0, 1), 0))


monopole_mirr = base_shape.mirror(App.Vector(0, 0, 0), App.Vector(0, 0, 1))
fused = monopole_obj.Shape
fused = fused.fuse(monopole_mirr)
monopole_obj.Shape = fused