In Alibre it's a python script and the function AddGearNP appears to need Pitch
Diameter .
==========================================
# default settings
NumberofTeeth = 20
PitchDiameter = 30
PressureAngle = 20
Thickness = 3
Win = Windows()
ScriptName = 'Gear Generator'
# create dialog window and show to user
Options = []
Options.append([None, WindowsInputTypes.Image, 'GearGenerator.png', 170])
Options.append(['Number of Teeth', WindowsInputTypes.Integer, NumberofTeeth])
Options.append(['Pitch Diameter (mm)', WindowsInputTypes.Real, PitchDiameter])
Options.append(['Pressure Angle', WindowsInputTypes.Real, PressureAngle])
Options.append(['Thickness (mm)', WindowsInputTypes.Real, Thickness])
Values = Win.OptionsDialog(ScriptName, Options, 170)
if Values == None:
sys.exit()
print "Working..."
# get user inputs
NumberofTeeth = Values[1]
PitchDiameter = Values[2]
PressureAngle = Values[3]
Thickness = Values[4]
# get current part
MyPart = CurrentPart()
# get the plane to create the gear on
GearPlane = MyPart.XYPlane
# create the sketch then extrude it
ProfileSketch = MyPart.AddGearNP("Profile", NumberofTeeth, PitchDiameter,
PressureAngle, 0, 0, False, GearPlane)
Gear = MyPart.AddExtrudeBoss("Gear", ProfileSketch, Thickness, False)
print "Done"
============================================================
Now if I add Module as a parameter, and into the dialog and then test on
PitchDiameter == 0 then I can create PitchDiameter from the number of teeth and
the module.
Next add the bearing reliefs, alignment holes and bevels on the teeth and bingo
a new 40T gear.
That took 15 minutes. But now I can use Module with Alibre.
John
> -----Original Message-----
> From: Gregg Eshelman via Emc-users [mailto:[email protected]]
> Sent: December-16-21 3:20 PM
> To: Enhanced Machine Controller (EMC)
> Cc: Gregg Eshelman
> Subject: Re: [Emc-users] Harmonic Drive
>
> Dunno why every CAD program with a gear wizard, generator etc doesn't do
> both. https://evolventdesign.com/pages/pitch-
> calculator
>
>
> On Thursday, December 16, 2021, 12:56:53 AM MST, John Dammeyer
> <[email protected]> wrote:
>
> The AlibreCAM Gear generator doesn't accept module.� Instead it wants number
> of teeth and pitch diameter.�
>
> So I whipped up a spreadsheet that converts say the module 1.25 that Todd
> used and chose 19 teeth for the sun gear.� That appears
> to be the right size pitch diameter for the test setup.� At least when I
> check it out with my calipers.� But of course 19T don't fit.� It
> has to be 20T and that then physically doesn't fit.�
>
> So creating a true planetary set with all the gears fitting appears to be a
> bit more difficult.
>
> John
>
>
>
> > -----Original Message-----
> > From: Gregg Eshelman via Emc-users [mailto:[email protected]]
> > Sent: December-15-21 8:22 PM
> > To: Enhanced Machine Controller (EMC)
> > Cc: Gregg Eshelman
> > Subject: Re: [Emc-users] Harmonic Drive
> >
> > Does FreeCAD's gear wizard support both Diametral Pitch and Module gears
> > now?
> >
> >
> >� � On Wednesday, December 15, 2021, 04:36:00 PM MST, John Dammeyer
> ><[email protected]> wrote:
> >
> >� I still haven't been able to make a simple circle in FreeCAD.? I keep
> >looking for the Alibre way of doing it which for my brain has
> > always been close to perfect.? Never could use AutoCAD and I find Fusion360
> > confusing .
> > However the gear tool is quite nice in FreeCAD.
> >
> > I'm still having some problem visualizing exactly how the gears turn to
> > create 67:1.? So I thought I'd blow a bunch of money on
> > filament and print them.? In hindsight I should have expanded the pinion
> > holes to 22mm since that's a standard (cheap) bearing
> size.
> >
> > Too late now.? Just over 2 hours before the other 4 are done.? I could make
> > some tubes that hold smaller diameter ones.? ? Or
> just
> > play with the motion here first.? See how it works and then decide if I
> > want to use my module 1.0mm cutters to make them out of
> > metal.
> >
> > Or just print ones with inset relief to hold 8x22x7 standard bearings.
> > John
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