
Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Adrian Tayne Mar 8, 2012 6:27 PM (in response to Mark Horne)I am not sure SW can help you with this one...a hand calc seems like the way to go.
Considering there is an uncountable number of arrangements the parts could take, you'll have to simplify it in a way that gives a reasonable "packing factor" which will be a close approximation to the average number of parts that will occupy the volume. The way I would do it is assume the parts are stacked in discrete layers with all of the parts being oriented on the flat side (thinking bottle caps here) and touching one another. Calculate the ratio of the volume occupied to the total volume of that layer. This gives you a packing factor. Find the volume of half the cylinder. Multiply the packing factor by the halfcylinder volume to find total volume of the parts. Divide that by the volume of one part.
This actually comes out to the maximum number of parts that you could fit into the volume.

Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Adrian Tayne Mar 8, 2012 6:39 PM (in response to Adrian Tayne)And actually now that I think about it, SW would make it easier to find the number of caps that would fit in one layer within the circular walls of the container.
Sketch out a circle to represent the part. Make a linear pattern at 30 degrees down and to the right.
Then make a linear pattern vertically with part diameter as the spacing
Make this 2D pattern big enough that you can sketch a circle that has the diameter of your cylinder container on top of it.
See how many whole circles fit inside the larger circle.


Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
14EQZK9 Mar 8, 2012 9:34 PM (in response to Mark Horne)Hi mark,
The fill pattern might be able to aid you in this  seem like it has everything you might need.
Regards
mark

Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Mark Horne Mar 8, 2012 11:06 PM (in response to 14EQZK9)Thanks for your thoughts. I am wondering how the fill pattern could be used to fill a 3D space? Or were you expanding on Adrian's direction by automating the fill within a 2d bounbdary?
I had a thought, is it possible to use Motion to fill a cylinder? I remember watching a tutorial where different size balls were filtered by corresponding sized holes to drop into holding spaces and were driven by gravity and surface contact. Hmmmm......
Any thoughts on that approach?

Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Nate Andrews May 1, 2012 8:11 PM (in response to Mark Horne)Mark,
As I was reading your explanation, the ball sorter was what I was thinking of. The tough part about that approach would be determining when you reach the halfway point. A plane with a sensor could do the trick, maybe?



Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Jerry Steiger May 1, 2012 8:02 PM (in response to Mark Horne)Mark,
If the cylinder is oriented with the axis vertical, then Adrian's method should give you a reasonable upper bound on how many parts you can fit. How close you get to that number will depend on the weight of the parts, the friction between them, vibration levels and a probably a bunch of other factors.
If the cylinder is oriented with the axis horizontal, then it is a much harder problem. The same basic idea would work, but now you are filling the space with little rectangles and they may tilt, making it much harder.
Jerry Steiger

Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Alin Vargatu May 1, 2012 11:56 PM (in response to Mark Horne)One possible solution (see attached).

Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Mark Horne May 3, 2012 2:59 PM (in response to Alin Vargatu)Thanks Alin, I did this as well and the boss was not satisfied. Sometimes what is asked of us just will not work, at least as easily as we picture it in minds eye.


Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Bengt Gustafsson May 3, 2012 2:44 PM (in response to Mark Horne)Hi Mark.
It is possible to do a motion simulation that will calculate one possible solution for, let's say, 1000 of your "caps" falling into a cylinder, taking into account that they bounce against the cylinder and into each other. However, unless you have a line into one of the mythical supermegamachines doing teraflops for breakfast, this would not be practical.
If you simplify the problem using, say, half a cylinder or a third, and limit the items to perhaps 50 or so, it is workable. Sure, it does take some time to calculate, but you can decrease the accuracy quite a lot since you are not after the exact movemen of the capst. You just want to see how they may end up, laying at the bottom.
I did a test with some 30 pieces, and it took about one hour to calculate  120 fps, 3d contact set low.
After the simulation, it is just a simple task of measuring how high the 50 pieces have reached and multiply until you reach half the cylinder, assuming that the cylinder is upright  axis pointing upward.
This should give you a fairly accurate idea of the total amount of pieces fitting into your cylinder.
//Bengt

Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Mark Horne May 3, 2012 3:02 PM (in response to Bengt Gustafsson)This is more what I had in mind. I will tell my boss we need an upgraded computer. Thanks for your effort. I will give it a try and let it run on the weekend.

Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Alin Vargatu May 3, 2012 3:46 PM (in response to Mark Horne)Keep in mind that a Simulation Study will give you one in a zillion of possible solutions.

Re: Fill 1/2 Cylinder Volume with Bottle Cap Shaped Parts
Bengt Gustafsson May 3, 2012 5:21 PM (in response to Alin Vargatu)Agree with you there Alin, thanks for stressing the point.
However, given that the items are small enough in comparision with the cylinder, the level of caps after they have come to rest
should still give a fair inclination of the actual physical result. Also, you could do several different runs with some changes in the initial position of the caps, and average the result. I suppose you could even give the cylinder a little shake at the end, to settle the items further. Have not tried that, though.Mark: Perhaps you should check for somewhere to buy computing time online, if this is just a onetime calc you need. Seem to remember reading about that somwhere in this very entertaining and enlightening forum.


