First Steps with Path WB

Here's the place for discussion related to CAM/CNC and the development of the Path module.
chrisb
Posts: 1859
Joined: Tue Mar 17, 2015 9:14 am

Re: First Steps with Path WB

Postby chrisb » Tue Mar 07, 2017 1:12 am

marcuswolschon wrote:In your introduction posting you don't tell what the difference between "Final Depth" and "Finish Depth" is.
Also I am missing any specification of what the material blank looks like.
At what stage shall the user specify where the 0-location in the work coordinate system is?
Another thing I missed in your posting was how to configure what your machine is capable of (speeds, work area, g-code flavor, max RPM, existence and placement of non-carthesian axis,...).
Is it correct that the feedrate and RPM have no (reduced) setting for high-chipload moves and that I can't specify any ramping angle for diving into the material?

As Herbert pointed out, this is not a tutorial let alone a documentation of the Path Workbench. It is for the very first steps, because they are very hard to go if you don't know where to begin.

As for the machine: what you ask for is defined in the post processor file. There are already several of these in the Mod/Path/PathScripts subdirectory of FreeCAD. They all end in "..._post.py".widely used is the linuxcnc_post.py fairly good configurable for new machines is the maho_post.py (which I like to recommend, because I wrote it myself; so don't take the recommendation too serious).
sliptonic
Posts: 621
Joined: Tue Oct 25, 2011 10:46 pm

Re: First Steps with Path WB

Postby sliptonic » Wed Mar 08, 2017 9:24 pm

marcuswolschon wrote:In your introduction posting you don't tell what the difference between "Final Depth" and "Finish Depth" is.


Final Depth is the depth at the bottom of the pocket or operation.
Finish Depth is the amount of material to remove on the last pass. You often want to control the amount of material being removed in that pass to ensure that the cutter is properly engaged without being too heavily loaded.

Another thing I missed in your posting was how to configure what your machine is capable of (speeds, work area, g-code flavor, max RPM, existence and placement of non-carthesian axis,...).
Is it correct that the feedrate and RPM have no (reduced) setting for high-chipload moves and that I can't specify any ramping angle for diving into the material?


Yep. Many things are still missing. Looking forward to your pull request. ;)
marcuswolschon
Posts: 22
Joined: Thu Sep 26, 2013 1:52 pm

Re: First Steps with Path WB

Postby marcuswolschon » Wed Mar 08, 2017 9:36 pm

Actually no.
I'd do 2 completely different operations for roughing and finishing.
So the first would leave 0.6mm of material and be a constant, deep engagement at the expense of not being precise at all with little changes in direction. Flat/constant radius surfaces would be cut in meander to save time even if the surface finish is bad.
The finishing would be very fast, shallow and with the highest RPM that works without rubbing, melting the material or setting it on fire.

I'm not good with Python and have way too many other project to juggle at this point. That automatic calculation of 2-part molds for complex meshes in FreeCAD is coming along nicely.
sliptonic
Posts: 621
Joined: Tue Oct 25, 2011 10:46 pm

Re: First Steps with Path WB

Postby sliptonic » Wed Mar 08, 2017 9:49 pm

marcuswolschon wrote:Actually no.

Actually, yes that is what it does. You asked the difference and I told you.

I'd do 2 completely different operations for roughing and finishing.
So the first would leave 0.6mm of material and be a constant, deep engagement at the expense of not being precise at all with little changes in direction. Flat/constant radius surfaces would be cut in meander to save time even if the surface finish is bad.
The finishing would be very fast, shallow and with the highest RPM that works without rubbing, melting the material or setting it on fire.

A perfectly valid strategy. Except we don't have a meander or adaptive roughing operation yet. When someone writes one, we can talk.

I'm not good with Python and have way too many other project to juggle at this point. That automatic calculation of 2-part molds for complex meshes in FreeCAD is coming along nicely.


I haven't seen any code for the 2-part molds but I'm interested. Send a link to even partial implementation and I'll take a look.
marcuswolschon
Posts: 22
Joined: Thu Sep 26, 2013 1:52 pm

Re: First Steps with Path WB

Postby marcuswolschon » Thu Mar 09, 2017 5:54 am

sliptonic wrote:
I'm not good with Python and have way too many other project to juggle at this point. That automatic calculation of 2-part molds for complex meshes in FreeCAD is coming along nicely.


I haven't seen any code for the 2-part molds but I'm interested. Send a link to even partial implementation and I'll take a look.


You got mail.
sliptonic
Posts: 621
Joined: Tue Oct 25, 2011 10:46 pm

Re: First Steps with Path WB

Postby sliptonic » Fri Mar 10, 2017 3:59 pm

marcuswolschon wrote:
sliptonic wrote:
I'm not good with Python and have way too many other project to juggle at this point. That automatic calculation of 2-part molds for complex meshes in FreeCAD is coming along nicely.


I haven't seen any code for the 2-part molds but I'm interested. Send a link to even partial implementation and I'll take a look.


You got mail.


Received your python program. It's an interesting approach. Since the intent is to generate 2 part molds, why does it produce 4 meshes?
marcuswolschon
Posts: 22
Joined: Thu Sep 26, 2013 1:52 pm

Re: First Steps with Path WB

Postby marcuswolschon » Fri Mar 10, 2017 4:04 pm

We should not derail this forum thread.