Re: Sorting Steel Balls

Hi Ethan,

You don't mention if you have one lot of 4k or are getting 500 and
hour.

Simple machine would seem to be one like they use for sorting coins
where size of the hole is the factor.

a pair of rails on a taper and on an angle would allow balls to roll
until they dropped through the opening of size equal to diameter.
nothing can get stuck as they are rolling into a larger opening and
everything is downhill.

your chutes for catching the balls determines what balls sizes you
have.

you could have a fast sort to handle the whole lot, then direct each
size group into their own slower more accurate sorting. this would
relieve the problem of balls rolling so fast as to bounce into the
wrong container. it would also speed the ball rolling. as the slower
speed, the more accurate and less momentium. you could easily get
much better accuracy than your one thou.

regarding CNC, you could pass each ball into a measuring chamber, say
a laser height gage. feed the measured height into a computer and
then by manipulating which container that is for that size ball,
toss/roll/slide said ball into said matching container.

For the quantity you have a contact measurement would wear and
require calibration.

if your balls are metal, you could pass them through a sluice with a
wire/electrode hung at the precise height and connected to a solenoid
so when a circuit was made the solenoid would open a gate, or pop the
ball so it would be directed to the chamber. seems that a lot of
stages (almost 300) would be needed for your range. This would also
work with a photo sensor for height measurement. but then you would
need a bunch to handle the whole lot at one time.

I think I like the angled rails for a pre-sort. Then with a batch of
very close size, your laser height gage could just select the needed
size. what I mean is you do a fast pre-sort then take the batch and
pass it past the height gage. After the height gage, have a bunch of
channels for that batch. way under size, way over size, then each
remaining channel 0.001. you would hopefully have a few over and
under which get sorted in the next round, and the remaining barrels
of the exact size you want.

with almost 300 sizes and a hang time of roughly 8 seconds, you need
to sort pretty quickly.

Dave

--- In CAD_CAM_EDM_DRO@y..., Ethan <ethan@f...> wrote:
> Good morning.
>
> I'm looking for some ideas on how to sort some steel balls. I need
to do
> about 4,000 per day. Sizes range from 19/32 to 7/8 with some sizes
being
> within .001 from each other.
>
> I'd like to use a PC or PLC based machine that will measure the
balls and
> them sort them according to size.
>
> Any and all ideas welcome.
>
> Thanks.
>
> Ethan