LibLathe - Lathe Path Generation

Here's the place for discussion related to CAM/CNC and the development of the Path module.
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Wsk8
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Re: LibLathe - Lathe Path Generation

Postby Wsk8 » Sat Feb 15, 2020 9:46 pm

Hello,
I'm also interested in this. Would be great if you could improve it so it will be usable and integrated in FC.

BR
blue0cean
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LibLathe - Lathe Path Generation

Postby blue0cean » Wed Mar 11, 2020 8:41 pm

It would be great if it were developed further. Could then use it on my lathe under LinusCNC. Can it be integrated into 0.19 afterwards?
dtay
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Re: LibLathe - Lathe Path Generation

Postby dtay » Fri Mar 13, 2020 7:53 pm

This looks pretty cool! I hope to see it progress.

I work with 5 axis millturn machinery and wanted to discuss how to drive tracking points on turning machines. My machines use a fixed set of 9 points. They do not rotate with the tool when a new tool orientation or B-axis position is established.

Bearing in mind the diagram below. I think that point#9 can be used as the master(which will be similar to milling tool paths) and then offset by the tool radius to the respective other 8 points.
Something like P9=path origin + corresponding offset X/Z as a radius:
P1=+X+Z
P2=+X-Z
P3=-X-Z
P4-X+Z
P5=+Z
P6=+X
P7=-Z
P8=-X
P9=0

You will see in the below diagram that each P value has a range of 45° for P1 through P8. If you for example start with P8 and then move the B-axis incrementally to +22.5 degrees, the new tool tracking point will be moved to P3. Does this making sense? I realize that this may be beyond the average hobby lathe, but I think it wouldn't hurt to look a little further down the road ;-)

The purple circle here represents the tool nose radius of a turning tool. The scheme can apply for all types of turning, back turning and grooving.
Image

This is more machine controller specific, but length, radius and Q (or off-center offset) is something to consider.
L=length
Q=Lathe offset(generally 0 when considering milling)
R=tool radius

There are multiple ways to move the tracking points away from center(or machine tool 0) for lathe tools. But "F" or "Q" seem to be somewhat standard for lathe tools. My vote would be for Q.


A grooving tool can have multiple tracking points. For example one side might be -Z(P3) and +Z(P4) for the other side of tool.

There is a lot to think about when it comes to turning on a CNC machine.

Thanks to Dubstar-04 everyone contributing to FreeCAD!

-Danny
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dubstar-04
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Re: LibLathe - Lathe Path Generation

Postby dubstar-04 » Sat Mar 14, 2020 8:50 am

Wsk8 wrote:
blue0cean wrote:
dtay wrote:
Thank you for the replies, it is great to see so much interest for lathe functionality in Path.

I am currently working on some non-lathe related features that I would like to try and get in to 0.19. Once 0.19 is released I will again turn my attention to Lib-Lathe.

Thanks,

Dan
blue0cean
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LibLathe - Lathe Path Generation

Postby blue0cean » Sat Mar 14, 2020 9:59 am

I'm really looking forward to it. Is there already an appointment for the 0.19?
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Wsk8
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Re: LibLathe - Lathe Path Generation

Postby Wsk8 » Sat Mar 14, 2020 10:59 am

I think somewhere in april, but it's not a fixed date, more like a wish :D

br
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dubstar-04
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Re: LibLathe - Lathe Path Generation

Postby dubstar-04 » Sat Mar 14, 2020 11:07 am

blue0cean wrote:
Sat Mar 14, 2020 9:59 am
I'm really looking forward to it. Is there already an appointment for the 0.19?
I think I read on a git comment that the target would be end of March for a feature freeze.

I'm in the process of testing as much as I can and fixing all the things I have broken! :D