FCGear problem pocketing hole

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
dgotc
Posts: 4
Joined: Tue May 24, 2022 6:12 pm

FCGear problem pocketing hole

Post by dgotc »

Hello All,

I'm learning FreeCAD v. 0.19 on Windows 10 as well as on Ubuntu and have run into an issue with creating a small gear using FCGear addon. It is actually two gears stacked. When I make a gear I can get it into a Body, create a sketch of a circle on one face and hole it through the two gears. If I create a Beta angle for the teeth on the first gear, the resulting part is un-hole-able with errors.

I tried attaching a *.FCStd of my project but it got an HTTP error from the website. Please see:
https://drive.google.com/file/d/17Wsb4A ... sp=sharing

My process is:
1. create gear with FCGear workbench, Beta angle of 30°
2. switch to Part Design workbench
3. select gear in side menu and click Create New Body: a new body appears with a BaseFeature that is the gear I just created
4. select top face and create another gear with same process in FCGear workbench, including position offset, then go back to Part Design workbench
4. select the bottom face of the gear and hit Create a New Sketch
5. make a 1.3mm radius circle and close the sketch
6. with the sketch selected hit Create a pocket

This is where normally you see the preview of the pocket but the whole model just disappears. if I hit OK on the pocket parameters it throws error "Pocket: Result has multiple solids. This is not supported at this time."

This issue does not occur if the initial Beta angle is set to 0°.

How do I get around this?

Thanks.
chrisb
Veteran
Posts: 53945
Joined: Tue Mar 17, 2015 9:14 am

Re: FCGear problem pocketing hole

Post by chrisb »

The problem is already in the step before. CheckGeometry shows two solids, which isn't allowed for a body, but is not detected before the pocket.
I would go for separate solids which can be unioned in Part workbench.

Besides: I don't recommend to attach sketches to faces. Here you can very well attach it to XY plane instead.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
User avatar
papyblaise
Veteran
Posts: 7877
Joined: Thu Jun 13, 2019 4:28 pm
Location: France

Re: FCGear problem pocketing hole

Post by papyblaise »

there is obviously a bug in the function: I redo the drawing by deliberately putting a space between the 2 and it does not indicate a fault of 2 objects in the same body
put the small pinion back to Z=0 and 5mm thick it will work

edit: if you make Z=1.99mm it also works, and you have to attach Sketch to XY
Attachments
Gear.JPG
Gear.JPG (49.41 KiB) Viewed 493 times
Gear_papy.FCStd
(638.2 KiB) Downloaded 7 times
Gear_papy.JPG
Gear_papy.JPG (56.81 KiB) Viewed 493 times
dgotc
Posts: 4
Joined: Tue May 24, 2022 6:12 pm

Re: FCGear problem pocketing hole

Post by dgotc »

chrisb wrote: Wed May 25, 2022 12:27 am The problem is already in the step before. CheckGeometry shows two solids, which isn't allowed for a body, but is not detected before the pocket.
I would go for separate solids which can be unioned in Part workbench.

Besides: I don't recommend to attach sketches to faces. Here you can very well attach it to XY plane instead.
Thanks for this guidance. I tried making the two gears in separate bodies and using Union in Part workbench. It worked when I selected the gear inside each body. The resulting "Fusion" was not able to be hole-ed through with Part Design workbench sketch on the XY plane. I tried making another body by clicking on the fusion and then clicking Create New Body. It put a BaseFeature within in the new body that is the fusioned shape, but it gave the same original error as in post 1 when I tried a hole through it.

Where am I going wrong with this?
dgotc
Posts: 4
Joined: Tue May 24, 2022 6:12 pm

Re: FCGear problem pocketing hole

Post by dgotc »

papyblaise wrote: Wed May 25, 2022 11:23 am there is obviously a bug in the function: I redo the drawing by deliberately putting a space between the 2 and it does not indicate a fault of 2 objects in the same body
put the small pinion back to Z=0 and 5mm thick it will work

edit: if you make Z=1.99mm it also works, and you have to attach Sketch to XY
I noticed a similar issue that I thought was a bug, but chalked it up to my lack of knowledge and skills with FreeCAD. I'll try to recreate your solution. Thank you.
dgotc
Posts: 4
Joined: Tue May 24, 2022 6:12 pm

Re: FCGear problem pocketing hole

Post by dgotc »

I positioned the 2nd gear at z=1.99mm. Then I made it's height 3.01mm to make up for the difference. Then the whole model reacted normally to manipulation. Thanks again.
Post Reply