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Originally Posted by TenPercenter Quote: |
Originally Posted by X-Files
I guess this is just the way clay chips are made. I do not think this is an issue in smaller stacks and I never even noticed before. I would have to say it is a non-issue. It does not bother me.
| Looks like another mark in the "plus column" for ceramics! Interesting.
Lego... want to break out some stacks of Egyptians for testing?  |
Sure!
Here's stacks of 50:
All stacks of rounds are the same height.
A stack of 50 plaques is about 1/3 chip shorter than the rounds
A stack of 50 octagons is about 1/4 to 1/3 chip taller than the rounds
BTW: I've been making a few chip thickness measurements on ASMs lately (CS and HH molds). A single chip will vary in thickness from side-to-side by 0.001" or so, while chip-to-chip thickness differences can run 0.005" or so. A consistent difference of 0.003" would stack up (pun intended) to a full chip thickness with 40 chips.
[speculation mode on]
I don't know much about the clay material or the compression-molding process, but I'm speculating that the material is not very compressible. The ultimate chip thickness would depend primarily on the amount of material being "compressed". If you wanted to guarantee stacks of 40 to be within 1/2 chip in height, you'd need to hold the tolerance to +/- .126/4/40 < .001". I don't know how those chip slabs are made... but holding a tolerance of .001" is not trivial with steel, let alone a cookie of clay glop.
Another way of looking at it would be the weight of the chip blank. If the material is incompressible, then the thickness will be proportional to the weight of the blank. To hold a tolerance of .001", you'd need to hold the weight of the blanks to .001/.126*10grams= 0.08 grams.
The only way I could imagine clay chips being consistent thickness within .001" would be to apply a finishing step to plane/sand/polish them after they were molded.
This speculative analysis is worst-case. In practice, it really wouldn't matter how much thickness variation there was in chips, as long as it was uniformly distributed. All the stacks would average out in height. But most mechanical manufacturing processes tend to be non-uniform in their tolerance distributions. There will typically be some systematic bias. For example, a machinist will remove material until the product is within tolerance, then he'll quit cutting on it. So machined things will tend to be towards the thick side. Holes will be towards the smallest acceptable diameter. An automated machine will be adjusted until the products are within some tolerance range, then they will chunk out a batch of products with narrow variance. You may get a batch of thick chips, while the next guy may get a batch of thinner chips.
By contrast, injection molded chips should be easier to control thickness-wise, since the mold itself can be ground and polished to very high accuracy, and the amount of material is metered by the mold itself.
Remember -- nipples are your best friend.
(Anybody ever seen nipples on a compression-molded chip?)[/speculation mode]
The best way to get a better handle on the chip thickness issue would be to take a micrometer to each individual chip, and gather the thickness distribution data. This should be done not only on an individual's batch of chips, but on comparable chips produced in different manufacturing runs.
Linear Mode
