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Tom McDonald <radiotitan@yanospamhoo.com> wrote in message
news:FxEoJG.Aq2@lugnet.com...
> In lugnet.lego.direct, Geoffrey Hyde writes:
> >
> >
> > Ian Sinclair <sinclair@cadvision.com> wrote in message
> > news:39643b6f.527169@mail.cadvision.com...
> >
> > > TLC wants to avoid changing molds as long as possible. Every time
> > > that's done the injection machine must be purged, cleaned and the
> > > molds changed. That is a lot of down time.
>
> This sounds like one of the few things that could stop the flow of ABS, • though
> I doubt it's cleaned inside very often.
>
> > Maybe that is the case, but I've seen one report that the facilities they
> > use are fed from a set of huge silos containing raw ABS materials in
> > different colors for all the common elements they produce.
> >
> > This suggests to me that perhaps their injection molding machines would • be
> > capable of automatically handling multiple colors one after the other.
> >
> > Basically, all that is needed is to spit out a small bit of ABS when
> > changing over to a new color, to flush the old one out of the injection
> > system. It might even be possible to have multiple colors at the • injection
> > point simultaneously, and just change colors on the fly or as demand for
> > pieces dictates.
>
> I totally agree. The unknown here seems to be how many pieces must go • through
> a mold before the new color completely (at least within tolerances) takes
> over.
Or do they have newer machines that simply flush out the old color with a
bit of compressed air or some kind of fluid under pressure?
> > > Therefore, you produce fairly large quantities of uncommon parts and
> > > store them till needed on the set production runs.
>
> The term "uncommon part" might be slightly misleading in this case if you
> exclude color. While red 2x2x2 windows are plentiful, the other colors of • that
> piece are not. Thus it makes sense that colors can be switched on the fly, • as
> LD is offering them in white, whereas in that color they've been • relatively
> rare before.
Indeed it might be uncommon - although I have noticed a lack of white 1x4x3
windows with shutters or indeed any color in that size.
> > This would probably be the case, but maybe they could also just switch • the
> > molds instead of the colors on a run. Quite feasible, have the old mold
> > automatically slip out and the new one in, computerized routing
> > automatically sends the parts to two or more designated bins for later
> > removal and storage until needed.
>
> This might be the case, esp. with newer molding machines. Since the basic
> bricks seem to be produced in quantities far surpassing other bricks, it • might
> make sense that a machine that usually produces 2x4 bricks, would produce • them
> most of the time, even though the color might change from time to time.
What I was thinking is that with the larger molds especially plates, that
there may be a small setting time after injection, to ensure that the
plastic stabilises. I'm not totally sure, the curing time might be so fast
it will stabilise right after it's molded.
> > Or if two parts are needed in about the same quantities in two different
> > sets, perhaps it could be automatically be programmed to switch back and
> > forth from one to the other - I'd still reckon they'd favour just molding
> > the entire production run in one or two large lots though.
>
> Color still seems to be easier to change IMO rather than a mold, as I can
> imagine that process would occur faster, as the machine would not have to
> pause as long (if at all) in the changeover.
Perhaps. Or maybe there is some new rotary feeder that holds anywhere from
six to ten molds at once and just feeds and releases in a preprogrammed
cycle? Who knows for sure.
> > I also wonder if any of the LEGO parts lend themselves to extrusion
> > molding - especially those small connector pegs with holes through them.
> > They look like a perfect candidate for extrusion molding at a first look.
>
> I can't imagine any other process used today other than extrusion for some
> pieces, esp. those. Some pieces are so detailed or complex that just • pouring
> in the plastic would take too much time for the plastic to fill all the • sharp
> little nooks and edging inside the molds by gravity alone. Yet, many light
> saber pieces have bubbles in them. So apparently not all pieces are molded • the
> same or with the same tolerances.
But is that intentional, or due to molding problems? :-) after all, a
lightsaber in the Star Wars movies were essentially a representation of
energies controlled by some advanced laser beaming system which was wielded
by the combatants. They sure made good cutting tools. :-)
> > I'm also fairly certain that if nothing else, the axles they use are • almost
> > certainly extrusion molded. I noticed that some early axles do have a
> > cutoff bump at one end of the axle where it gets separated from the sprue • it
> > would be on, but I haven't seen any such bumps in more recent axles, • which
> > would seem to suggest that they're either using extrusion molding for the
> > axles, or are developing extremely accurate part separation machinery.
>
> I would guess extrusion.
>
> > I guess they would also recycle the excess ABS - if they
> > used more than two parts in each mold the excess ABS could probably make
> > another couple hundred worth of pieces, if they are able to reclaim and
> > recycle it.
>
> Perhaps some black pieces start their lives this way.
Maybe. Is ABS recyclable? Earlier stuff would certainly bio-degrade ...
> -Tom McD.
> when replying, enjoy that ancient favorite British summertime treat today:
> spamcake pudding!
Leave it to the British ... Hehe.
Cheers ...
Geoffrey Hyde
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Message is in Reply To:
 | | Re: Bulk Sales in the 21st Century
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| (...) This sounds like one of the few things that could stop the flow of ABS, though I doubt it's cleaned inside very often. (...) I totally agree. The unknown here seems to be how many pieces must go through a mold before the new color completely (...) (24 years ago, 9-Jul-00, to lugnet.lego.direct, lugnet.general)
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