Hi Barry,

Sometimes on TV, machinery in "bottling plants" is shown, pretty amazing what is done.

I recall seeing this subject on the internet before.
A google search of "bottle feed screw design," produces some hits.

Also the recent script to unwrap helices, Blend the helices, and re-wrap to cylinder, might be helpful for transitions?

- Brian

Hi Brian,
thanks will look at your idea for transitions.
Here's a video showing another method
where the bottle is rotated as it is traveling
along the screw. The orientation is done linearly
and the shaft is rotated and each bottle is subtracted
In order. https://youtu.be/jTktmo5N7G4
I am wondering if this way may be possible with
Max's node editor.

Barry

Hi Barry,

re:
> Unfortunately it's not possible to rotate the bottle with the array along curve.

Can you please post a 3DM model file with your curve and bottle setup so I could take a look at the problem you're seeing with array along curve?

- Michael

Hi Michael,
attached is a photo showing what I mean. The file size is 11meg so I haven't uploaded it.
From the photo you can see the bottle is arrayed along the helix and then subtracted from
the shaft thus giving a faceted result that is the basis to construct a smooth screw.
The bottom of the photo shows the required bottle rotation as it moves along the screw.
If this was just a profile the start and the end profile could be produced by a sweep of
the helix but this does not work for this project.

thanks
Barry

Michael,
this video shows what is required
https://youtu.be/k4xHPKlHF0c
The bottle is always vertical to the horizontal
screws and only rotates in the plan view.

Cheers
Barry

Solution will be an Array Curve with Object rotation but that is not yet existing...
So...
Maybe something like this ?

After considerable google searching, some promising information, which seems helpful in understanding the requirements, was located.

There is a free "Feedscrew Generator" for solidworks at mecad. The installer is an .exe, so without Solidworks, not much help, but
there are some tutorials.:
https://mecad.co.za/
https://mecad.co.za/feedscrew-add-update/
http://mecad.co.za/feedscrew-basics/
https://mecad.co.za/feedscrew-addin-part-2-different-profiles-ins-outs/

There is also a Feed Scroll Generator Addin for Autodesk Inventor, many videos, and 26 page tutorial.
The 26 page tutorial is downloadable as pdf.
http://www.ldcadsolutions.co.uk/feed-scroll-generator.html
https://www.youtube.com/watch?v=ih67Mme2CLs
https://www.youtube.com/watch?v=gO1uVZ_f978
I have not located the actual Addin, it must be commercial.

So the algorithm would be something like diamond cutting, using a cutting object, the bottle, which could be one of a number of various shapes.
The screw begins as a long horizontal cylinder.
The cutter, or bottle, intersects the cylinder at right angles at the starting (left) end, to some depth radius, and is Boolean subtracted.
Then the cylinder rotates delta_theta, the bottle moves to the right delta_distance, (which could be a variable distance) and the bottle rotates delta_psi, and is Boolean subtracted again. Repeat until right end is reached.
(Or some alternative continuous version of the above... lofting profiles?)

- Brian

Hi Barry, wow that's pretty fancy! Yeah that might be a job for the Node editor to replicate a shape with specific constraints on rotation like that.

What about maybe doing a sweep through multiple profiles to build a cutting shape, with these profiles, Twist = Flat with twist direction along helix axis:







I don't think that's quite exactly the same though, the profile is being rotated around the helix axis and rotation in the other direction comes from morphing from one profile to the next.

Can you tell me more about the rotation, is it a constant increment for each step along the helix? So it's like a 90 degree total rotation from start to end, with each step having the same rotation divided up by number of stations? Or is the rotation more complicated than that?

- Michael

Hi Brian,
I'm aware of the autodesk addon and also the video's
that's what started my interest in trying to produce it
in Moi with the array along path.
The only issue is it's not possible to input a rotation that
is why I am leaning towards the turbocad video of laying
the bottles in a line ( with the desired rotations )parallel
to the shaft and then rotating the shaft in steps and
subtracting the bottles one by one.
( but would need an array script with quantity, distance
and rotation even for this )
Pilou thank you but not sure if it would work in this case.
Thanks
Barry

Hi Michael,
the rotation can be a constant step from
start to finish so as I've mentioned in my
posts a linear array with rotation step input
would help if this could be done within Max's
Node editor.
Thanks
Barry

Deleted my faulty thinking about 2d profile sweep.
The bottles remain vertical, so the intersecting pard of the whole bottle needs to be Boolean subtracted from the cylinder...

- Brian

Hi Barry, please try the attached plug-in, hopefully it does the type of arraying you need. Put the object at the start of your helix and it will only rotate it in the Front view. You give it the number of stations and total rotation angle. Instructions for installing a plug-in here.

- Michael

Hi Brian,
you will see from the Autodesk plugin that it
produces facets and I think it then uses the facet
edges to loft thus giving a smooth finish.
I've found given a constant helix and no rotation
you only have to generate enough facets on a small
part of the helix to produce a profile that you can
then sweep to get a screw.
If it was just point contact it's possible to calculate
the profile width from the helix angle bottle width
shaft outer diameter and inner diameter but this
is not what I see in the videos on YouTube.
Cheers
Barry

Hi Barry, also I suppose it would be nice to generate the convex hull between each pair of cutting bottles but unfortunately I don't have anything that would do that.

Also just wanted to make sure you saw the plug-in above, I think we were writing posts at the same time.

- Michael

Here's a demo of using the BottleFeedArray plugin, if you use a lot of stations it can cause problems with the booleans with things just barely grazing each other. I had some better success on denser ones with unioning the bottles together first before differencing them from the main body:









I can imagine that the convex hull between each pair would make for a nicer imprint. That's a lot easier to do on a triangle mesh than on curved solids though.

- Michael

Result must be smoothing of you must have sharp edges inside (each part 's bottle visible) ?

@ Michael
so does it possible to add the Rotation option of the profile inside the native Array Curve Function ?
Now there is only the orientation's rotation of the curve itself! (in the Array curve function)

Hi Michael,
thanks for the script but unfortunately its rotation is in the wrong axis.
Attached is a basic drawing where I have manually rotated a few bottles and
placed them on the helix. You can see from the photo's the facets are cut at
90 degrees to the shaft axis. Also I have shown the result of using the profiles only
and sweep you can see if the profiles where extruded they would cut thro the screw.
The array along curve drawing shows the bottles arrayed at 90 degrees to the shaft but
with no rotation.
Cheers
Barry

This one ?
http://moiscript.weebly.com/uploads/3/9/3/8/3938813/foret.3dm
A simple Sweep

Re Michaels BottleFeedArray script:
I am getting the bottle rotation about the axis of the bottle, but am not getting any rotation of the bottle around the axis of the helix.
- Brian