How do I cut the involute gear through

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help

Also, be nice to others! Read the FreeCAD code of conduct!
Post Reply
TopDown
Posts: 159
Joined: Thu Jun 21, 2018 10:00 am

How do I cut the involute gear through

Post by TopDown »

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.13971 (Git)
Build type: Release
Branch: master
Hash: 8e4dd8ca8496595d4718dc24c872f7ed668b2521
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/Australia (en_AU)

I want to use the Involute gear template to cut the teeth through the green area?
involute cut.PNG
involute cut.PNG (64.55 KiB) Viewed 710 times
Thanks for any guidance,
Gary.
Attachments
wheelGearAndShaft.FCStd
(158.83 KiB) Downloaded 11 times
User avatar
meme2704
Veteran
Posts: 2926
Joined: Sat Apr 01, 2017 2:47 pm
Location: Vosges

Re: How do I cut the involute gear through

Post by meme2704 »

Hi
you extrude the pinion big enough to encompass all the wheel and its axis, and to make a common booleen with the pinion and the wheel
Attachments
roue train crémaillère.PNG
roue train crémaillère.PNG (81.69 KiB) Viewed 693 times
chrisb
Veteran
Posts: 54183
Joined: Tue Mar 17, 2015 9:14 am

Re: How do I cut the involute gear through

Post by chrisb »

It would have been best to start with an additive gear. Now you can move the gear out of the body, use Part-Extrude for 3000mm reversed and make a boolean Common. If you want to continue working on it in PartDesign, you have to create a new body with Common as BaseFeature.

The file is too big to attach.
Attachments
Bildschirmfoto 2019-04-23 um 08.36.35.png
Bildschirmfoto 2019-04-23 um 08.36.35.png (56.67 KiB) Viewed 690 times
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
kisolre
Veteran
Posts: 4166
Joined: Wed Nov 21, 2018 1:13 pm

Re: How do I cut the involute gear through

Post by kisolre »

While this will work it is not the proper way to do it. You should not use features of a body outside of the body. This will give "Links go out of scope" warnings/errors:
LinkOutOfScope_02.JPG
LinkOutOfScope_02.JPG (85.23 KiB) Viewed 688 times
.
The Common operation should be done with the body itself and not with its last feature (pollar pattern):
LinkOutOfScope_03.JPG
LinkOutOfScope_03.JPG (74.12 KiB) Viewed 688 times
.
and the Part extrude should be done with the gear profile OUTSIDE the body (you can drag it from the body on to the file name to do that):
LinkOutOfScope_04.JPG
LinkOutOfScope_04.JPG (91.65 KiB) Viewed 688 times
.
After you do that you should yse the Common as BaseFeature for a new body if you need to continue adding PartDesign features:
Common As BaseFeature.JPG
Common As BaseFeature.JPG (89.75 KiB) Viewed 688 times
kisolre
Veteran
Posts: 4166
Joined: Wed Nov 21, 2018 1:13 pm

Re: How do I cut the involute gear through

Post by kisolre »

Another way is to convert that gear profile to sketch, (Draft/Draft to sketch), drag that to the body, draw a circle around the gear profile and use that to pocket through all:
DraftToSketch.JPG
DraftToSketch.JPG (101.87 KiB) Viewed 683 times
.
But as Chrisb mentioned better start with the PartDesign Involute gear and add features to that. You already have all your sketches so this should not be very hard to recreate.
User avatar
meme2704
Veteran
Posts: 2926
Joined: Sat Apr 01, 2017 2:47 pm
Location: Vosges

Re: How do I cut the involute gear through

Post by meme2704 »

Another way is to convert that gear profile to sketch, (Draft/Draft to sketch), drag that to the body, draw a circle around the gear profile and use that to pocket through all:
In this way, be careful not to use internal involute gear, but a negative of external involute gear, because the profiles are not the same.
chrisb
Veteran
Posts: 54183
Joined: Tue Mar 17, 2015 9:14 am

Re: How do I cut the involute gear through

Post by chrisb »

To make things clear: Some references became unclear due to intermediate posts:
- meme2704 and I were both referencing the original first post.
- kisolre referenced meme2704's first post, where indeed a feature is used in a Part boolean operation.

There is another way, staying in PartDesign:
- Create the gear in a new body
- Add a boolean operation in the first body
- Set the type of the operation to Common and add the second body, which contains the gear.

I should mention that the filesize rises from 1.2MB with the Part-booleans to 2.0MB with the PartDesign-booleans.

This is how the tree will look like:
Attachments
Bildschirmfoto 2019-04-23 um 12.28.15.png
Bildschirmfoto 2019-04-23 um 12.28.15.png (53.51 KiB) Viewed 665 times
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
TopDown
Posts: 159
Joined: Thu Jun 21, 2018 10:00 am

Re: How do I cut the involute gear through

Post by TopDown »

Thanks everybody,
I will look into all the advice and (hopefully) learn a little.

I will report back ASAP>
User avatar
meme2704
Veteran
Posts: 2926
Joined: Sat Apr 01, 2017 2:47 pm
Location: Vosges

Re: How do I cut the involute gear through

Post by meme2704 »

Bon Ok, here is 1 other aproch with only 1 body and all on the body and in only 932K0
Attachments
wheelgear1.FCStd
(932.71 KiB) Downloaded 11 times
TopDown
Posts: 159
Joined: Thu Jun 21, 2018 10:00 am

Re: How do I cut the involute gear through

Post by TopDown »

Thanks again everybody.

I have tried the various options, some with more success than others (this is a statement of my skill level not the suggestions).

Ultimately I ended up using ChrisB's suggestion using another body and a boolean operation.

I certainly gained a better understanding of things whilst trying the various options. Hopefully some of it will stick.

Cheers.
Post Reply