Drawing 100 tooth HTD 3M timing pulley

[ljoets]

Hi all,
I have to draw a 100 tooth HTD 3M timing pulley and export it in SVG format (I just need a top view).
I found tooth profile characteristics here : https://www.solidrop.net/photo-7/cnc-ma ... ulleys.jpg
Is there a tip to draw it with FreeCAD ?
I am able to draw one teeth, but I don't know how to proceed after that.
What should be the correct way to do that ?
Thanks !

[DeepSOIC]

Draft Array (change it into polar using properties). Then, you can try exporting it as is. If you want to extrude it, you'll need to stitch it together. Maybe Fuse property of draft array will help, but if not, Part JoinConnect can.

[ljoets]

Thanks for your answer. But I know how to draw the first teeth in a sketch with "Part design". I don't know how to draw it with Draft toolbox. Is is possible to add constraints ?

[ppemawm]

Is there a tip to draw it with FreeCAD ?

I would sketch the space between the teeth and cut it from the pulley. Then you can use PartDesign/PolarPattern. See the example below:

Capture.JPG (73.26 KiB) Viewed 873 times

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6712 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: da2d364457257a7a8c6fb2137cea12c45becd71a
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

[ljoets]

Thanks,
that is a good idea, but I just need a top view in SVG format tu use it with a laser cutter or a CNC.
Perhaps FreeCAD is not the right tool to do this ?

[DeepSOIC]

I just need a top view in SVG format tu use it with a laser cutter or a CNC.
Perhaps FreeCAD is not the right tool to do this ?

FreeCAD IS the right tool for the job!

You can extract the outline for an svg with quite a few methods, such as Draft Downgrade, or maybe Draft Shape2DView, or Part Common with a face.

But I know how to draw the first teeth in a sketch with "Part design". I don't know how to draw it with Draft toolbox

It is not a problem, you can mix tools from different workbenches. Sure, there are limitations, but many workbenches can be combined to achieve the result.

My tutorial for Lattice2 add-on workbench might be helpful:
https://github.com/DeepSOIC/Lattice2/wi ... t-Tutorial

[ppemawm]

I just need a top view in SVG format

Use the Drawing workbench to create the view then you can export as SVG file:

[ljoets]

Thanks to all !
I did the job !

[oldmachine]

Just curious... Your opening comment & link suggests you want a HTD-M tooth. That is different than the one in the follow-up comments (radius'd bottom Versus rectangular...).

According to the dim's in the link, this is what the tooth looks like...

[ljoets]

Is someone can tell me why 2 tooth are not cutted ?

Capture d'écran de 2018-05-16 20-56-48.png (23.61 KiB) Viewed 811 times

Capture d'écran de 2018-05-16 20-56-38.png (2.51 KiB) Viewed 811 times

Poulie HTD-3M 100T.fcstd

(229.94 KiB) Downloaded 44 times

Thanks