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Subject: 
Re: LEGO Quality Control
Newsgroups: 
lugnet.ambassadors
Date: 
Thu, 4 Sep 2008 08:22:19 GMT
Viewed: 
17043 times
  
In lugnet.ambassadors, Tommy Armstrong wrote:
   From what I gather, and this has been discussed before-probably by me, but the general gist of the problem occurred when a paradigm shift in the coloration of the parts was made. The way it was explained to me, and this is from a bit muddled memory, was that now LEGO essentially mixes the colorant at the machine.

Yes, that was what they announced sometime in the past couple years. I can’t remember when the change took place, but I do know that they had inconsistent shading in the dark-purple bricks that they used to make the Knight Bus in 2004. There were similar problems with dark-red bricks around the same time as well, judging by the dark-red 1x10 bricks that I bought through Bricklink.
   There is a word for the “scrap” that I cannot recall.

It’s a sprue if it’s the plastic frame that small parts are molded into (like the round thing that the 6-piece tool set ships attached to), I can’t recall the specific term for plastic that’s ejected without being formed (but there is a term for it), and everything that’s been reclaimed and chopped up into pellets that are small enough to be put back through the process is called regrind (I used to work for a vacuum-forming/fabrication company that primarily worked with ABS).

   Perfection with anything that has to do with color is simply not possible,

It is if you’re dealing with black. Black trumps everything, at least in ABS. The pigment they use for black ABS is carbon, which is strong enough to overpower every color you might throw in for regrind (provided you don’t throw in too much off-color regrind, that is, or you actually could get color streaks). In the case of a rarely-used color that they have trouble keeping consistent, my first suggestion would be to suck up the cost difference and recycle the special regrind into black bricks. That eliminates the biggest problem with ironing out the color consistency (that being that any past errors will continue to taint future batches), while still making sure that the scrap isn’t wasted. I can guarantee that it works, because the company I used to work for made white parts in FDA-grade plastic. That certification requires that no post-consumer regrind makes it back into the new plastic, so in order to reclaim our white scrap we had to recycle it into a different color of plastic. The obvious choice was black, because all that anyone had to do was make sure that it was sufficiently mixed in with the black regrind. I believe we later experimented with having our extruder recycle it into OSHA yellow and OSHA orange sheet, since their system was supposed to be sophisticated enough to compensate for the difference (and we could afford to have some noticable variation in color from one batch to the next...unlike The LEGO Company). Thing is, for all the slight variation we had with yellow, orange, and even sometimes with white (like white LEGO bricks, our white stock would yellow with age). There was never any variation in the black sheet, and we used a lot more of that than all other colors combined. I would especially urge that they consider this possibility if it would straighten things out enough that they could repeal this alleged ban on purple parts.



Message has 1 Reply:
  Re: LEGO Quality Control
 
(...) Actually it really does not. I have polished literally thousands of black bricks and when one brings the to a high polish variations are very evident to me. One can tell which have red or blue or green regrind in them. It is true that black (...) (16 years ago, 4-Sep-08, to lugnet.ambassadors, FTX)

Message is in Reply To:
  Re: LEGO Quality Control
 
I actually had a pretty long and very interesting discussion with Bjarke Schønwandt at BrickFair about the whole color issue. I am pretty much of an expert in color quality control-it was my job for many many years to make sure batch to batch color (...) (16 years ago, 4-Sep-08, to lugnet.ambassadors, FTX)

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