boolean cut off a piece of M30*1.5 threaded rod

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!
TLS
Posts: 38
Joined: Wed Apr 15, 2015 9:04 am

boolean cut off a piece of M30*1.5 threaded rod

Post by TLS »

Hi, I managed to create a piece of M30*1.5mm (pitch) rod.

But in order to be able to 3D print it, I need it to have a flat surface. When i substract a cube from the rod the result is not correct.

What could this be?

Unfortunately the file is too big(2.2Mb) to post
User avatar
bejant
Veteran
Posts: 6075
Joined: Thu Jul 11, 2013 3:06 pm

Re: boolean cut off a piece of M30*1.5 threaded rod

Post by bejant »

TLS wrote:What could this be?

Unfortunately the file is too big(2.2Mb) to post

Without the model we're guessing. Can you upload your model to a free file sharing service like Dropbox so someone can have a look at it?
https://www.dropbox.com/login?lhs_type=anywhere
TLS
Posts: 38
Joined: Wed Apr 15, 2015 9:04 am

Re: boolean cut off a piece of M30*1.5 threaded rod

Post by TLS »

this will make things easyer:

https://www.dropbox.com/s/ia0cuktu4oqou ... FCStd?dl=0

I tried making some overlap not to have coplanar faces, but didn't work.

thanks
ickby
Veteran
Posts: 3116
Joined: Wed Oct 05, 2011 7:36 am

Re: boolean cut off a piece of M30*1.5 threaded rod

Post by ickby »

Your sweep intersects itself, it is therefore a invalid geometry and the boolean fails. You need to correct the sweep.
TLS
Posts: 38
Joined: Wed Apr 15, 2015 9:04 am

Re: boolean cut off a piece of M30*1.5 threaded rod

Post by TLS »

Hi Ickby

I want to make a threaded rod and not a spring. How can i avoid overlapping but keep a solid structure?

Is only making the threads and join the with a cylinder the way to go?
User avatar
DeepSOIC
Veteran
Posts: 7896
Joined: Fri Aug 29, 2014 12:45 am
Location: used to be Saint-Petersburg, Russia

Re: boolean cut off a piece of M30*1.5 threaded rod

Post by DeepSOIC »

Hi! consider using screw maker macro.
I also recommend you check out this thread on threads: Cut goes black
User avatar
quick61
Veteran
Posts: 3803
Joined: Sat Aug 24, 2013 2:49 am
Location: u.S.A.

Re: boolean cut off a piece of M30*1.5 threaded rod

Post by quick61 »

I will mention that there is a way to "cheat" around this. Mesh the thread and then mesh the cube your planing to use for the Cut, and do the Boolean difference, (Cut) on the meshes. ;)

If the Cut fails for some reason in the Mesh Design Workbench - FreeCAD does NOT have it's main focus on mesh modeling - you can import the threaded rod as a mesh into a program like Blender and do the Cut there with Add modifier > Boolean.

Mark
This post made with 0.0% Micro$oft products - GOT LINUX?
TLS
Posts: 38
Joined: Wed Apr 15, 2015 9:04 am

Re: boolean cut off a piece of M30*1.5 threaded rod

Post by TLS »

I managed to get it working by creating the thread itself, and by joining a cylinder in the middle.

I have tried this screwmaker, but is does not allow to define a custom thread. So M30 goes with bigger pitch than 1.5mm
TLS
Posts: 38
Joined: Wed Apr 15, 2015 9:04 am

Re: boolean cut off a piece of M30*1.5 threaded rod

Post by TLS »

To make matters even more complicated, in fact I need an 'adapter' for going from M30-1.5mm to M28-1.5mm

so a part with M30-1.5mm outer thread, and M28-1.5mm inner thread.

The thread need to be aligned or the object cannot be manifold. I managed to make the object with outer&inner thread, and it's valid-manifold.

However cutting top and bottom is a problem. I suppose this is a challenge?

file with M28M30:
https://www.dropbox.com/s/9p2ip8xr9r5wx ... FCStd?dl=0
User avatar
tanderson69
Veteran
Posts: 1626
Joined: Thu Feb 18, 2010 1:07 am

Re: boolean cut off a piece of M30*1.5 threaded rod

Post by tanderson69 »

Are you using the command part/check geometry? If not, start. Do you have the bopalgo option for part/check geometry turned on? If not, turn it on. go here http://www.freecadweb.org/wiki/index.ph ... ckGeometry. Word of caution: this option can make the command run REAL slow. That is why it is an option. You will not want to run it on your complete sweep.

Once you go past your first revolution geometry starts coinciding. This is a bad condition! Consider following picture. We stop the helix short of a complete turn and the solid passes all geometry checks.
under1Rotation.png
under1Rotation.png (82.33 KiB) Viewed 3249 times
Now in this picture the helix goes just past first turn. Notice the geometry errors.
over1Rotation.png
over1Rotation.png (122.69 KiB) Viewed 3249 times
Post Reply