First attempt to do 4 axis toolpaths from a 3D model

[quoy25]

Merci David , et chapeau bas pour cet utilitaire indispensable !
principe simple dans le concept, fallait y penser ! encore une fois bravo , je teste des que possible ...

[dh42]

Hello

I just adds a plugin version on the website

http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/Unroll3D.html

http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/Unroll3D_FR.html

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David

[SquibLoad]

This is fantastic, I can't wait to try it!

Would it be possible to allow the choice of which axis to align?
Many milling machines orient a 4th axis along the X axis rather than the Y axis.

Regardless, thanks for this!

It seems that the release of CamBam 1.0 has inspired quite a burst of creativity.
Many, many excellent new plugins have arrived in the last few months, or updates and enhancements to older plugins.
Great fun!

[EddyCurrent]

Hello

I just adds a plugin version on the website

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David

Nice one 

[dh42]

Hello

Would it be possible to allow the choice of which axis to align?

The unroll orientation is not really linked to the 4th axis alignment, it only generate a surface ; just rotate the resulting unrolled surface by 90° before applying the 3D mop, so you are able to wrap it on another axis.

For the next release (if that works  ) I planed a 'test diameter' button that will allow to check for the min stock diameter needed to cut the shape (not always easy to find if the model have a tortuous shape) ; I also want to try to speed up calculation, that is very slow 

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David

[EddyCurrent]

David,

Why not combine it with Wrapper, or at least parts of it ?

[dh42]

Not sure what can be combined    Wrapper act only on a Gcode and after the shape has been unrolled there is MOP creation that remain to do and job to do with boundaries to avoid that the tool down at the ends.

currently, on the wrapper side, I just set the base Z to the same value as unroll radius, and the diameter to 2x the radius.

With the integrated wrap option in the post pro, there is no way to set the wrap diameter, it is the stock surface value of each mop that is used as wrap radius.

If you want to use the PP to wrap, you must change some setting on a copy of you preferred PP.

1) in the Rotary section, set the right value for Axis of spin and Rotary axis. (in my case, Y and A)

Axis of spin define the axis of alignment of the 4th axis, Rotary axis define the letter used for the 4th axis

2) set rotary wrap to True to enable GCode wrapping

3) you must also edit the macro in the Moves and Canned Cycles sections to remove the axis that is wrapped.

In my case my 4th axis is aligned on Y, so it is the X that is wrapped.

In all macros, I remove the {$_x} macro, so for feedmove the build-in macro is {$g1} {$_f} {$_x} {$_y} {$_z} {$_a} {$_b} {$_c} and become {$g1} {$_f} {$_y} {$_z} {$_a} {$_b} {$_c}

It is not needed to set the Arc Output to convert to line, it is done automatically when Rotary wrap is used.

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I attach a CB model that has been done with the following settings.

The unroll settings


The Wrapper settings


The result on NCplot


With CB V1.0, the wrapper plugin is no longer needed for this king of job where rotation is always 360° and the Wrap with the PP is really simpler to use than the plugin.

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David

[Uriel]

Merci beaucoup David, super job !  

I had just finalized the code that gave the same thing under blender !

But I notice (if I not mistaken) that it will ignore the fact that the milling cutter have to be smaller in width as we get closer to zero on Z axis. (For don't touche the near shapes).

I search to try to make a simple script (on CamBam) that scan only make one passage in 3D along the axis of rotation, and rotate the object of "X" degrees and repeat the operation as selected times.

And after that, keep every toolpath to make only one.
Have I been clear?

Thank you ! And have a good day  

Friendly

[dh42]

Hello

But I notice (if I not mistaken) that it will ignore the fact that the milling cutter have to be smaller in width as we get closer to zero on Z axis. (For don't touche the near shapes).

The plugin dot not return toolpaths, it just scan the 3D model and unroll it, so you get the same surface, but unrolled. The tool correction is done by the 3D MOP itself when applied.

I search to try to make a simple script (on CamBam) that scan only make one passage in 3D along the axis of rotation, and rotate the object of "X" degrees and repeat the operation as selected times.

I attached a script version on this message, maybe it can be of some help.
http://www.cambam.co.uk/forum/index.php?topic=6427.msg51417#msg51417

Also, for French users, there is a small doc here
http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/Unroll3D_doc_FR.html

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David

[Uriel]

Thank you David.

I know that the plugin dot not return toolpaths 
Thank you for your sripts and documentation.

But if we will a "real" toolpath who respect the fact that the tool is more likely to touch the shapes near the bottom than at the top, we are forced to use rotation+toolpath.

A simple wrappage don't do that. (except with a good post processing who inclued this contraint, but I don't think that on this presented)

(Note : And for my CNC it is more simple, I don't need to wrap, I have wired a swich toggle who permute the Y axis to rotary axis and so, a simple XYZ toolpath work very well !)

have a good day 

[Mark81]

This is a great plugin!
The process is quite cumbersome but it might work 

Just a couple of clarifications:

1. what's the purpose of adding polylines for each step? I mean, when you would want them?
2. I'm not sure to understand the meaning of the Z min field. It's just a limit? Say my surface as a maximum radius of 20 mm and a minimum of 5 mm. If I set Z min = 10 mm all the points closer (to the origin) than 10 mm are not machined, right?
3. is there a rule of thumb to find a trade off for angular steps and axial stepover? I was tempted to set 360 and 0.1 mm but for my stl it leads to 2M of triangles... I bet they are too much...

[dh42]

Hello

I just finished the EN doc for the plugin

http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/Unroll3D_doc_EN.html

1. what's the purpose of adding polylines for each step? I mean, when you would want them?

Maybe it's useless, but the polylines are used to generate the surface, so I keep them ... just in case   ... maybe they can be exported as DXF to another CAD software to generate bspline surfaces ... not tested or with an engrave mop and a "large" angular step to do .... strange things ...  

2. I'm not sure to understand the meaning of the Z min field. It's just a limit? Say my surface as a maximum radius of 20 mm and a minimum of 5 mm. If I set Z min = 10 mm all the points closer (to the origin) than 10 mm are not machined, right?

you will get a flat surface at Z = 10 on the unrolled surface in this case ; all details below 10 will disappears.

3. is there a rule of thumb to find a trade off for angular steps and axial stepover? I was tempted to set 360 and 0.1 mm but for my stl it leads to 2M of triangles... I bet they are too much...

Not really, it's certainly depending of the model ... but be careful currently the plugin is very slow, so it can take a while with hight resolution values ... !

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David

[Bubba]

The process is quite cumbersome but it might work.
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It maybe cumbersome but it works fine. I do 4th axis work often and can assure you once you understand the process it make not so. I come from conventional machining, did enormous amount of work either on rotary table or dividing head so understanding those setting come handy here. With Davids plugin it makes that much better. As far as I know even MasterCam considered by many as the cadillac of  Cam's is using similar process and it cost..? I'm sure you don't want to know. Good luck.

[Mark81]

Thanks a lot for the explanations and the documentations. I'm going to give it a try.

The Z min at -10 means that the plugin will test the shape up to 10mm below its axis, which is necessary here because some areas are lower than the axis of rotation.

Because the plugin doesn't calculate this value automatically, it's safe to set it = 0 if there are not areas below the axis?

[dh42]

Because the plugin doesn't calculate this value automatically, it's safe to set it = 0 if there are not areas below the axis?

Yes, but even if you set it to the lower possible position of the model (- radius) it works too and I'm not sure that calculation time is affected ..

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David