Comment by msds | Hacker News Reader

Comment by msds | Hacker News Reader

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For cheap glass with big error bars on refractive index, dispersion, and defects, the process is entirely automated - think window glass or beer bottles. Quality control is still hard, and a lot gets recycled as cullet or discarded, but that isn't too much of a problem, since it's cheap. When you're working at that sort of scale, the furnace/melt behavior tends to be quite predictable and stable as well. Once you've dialed it in, it's good for quite a bit.

For such small batches of glass (500kgs is nothing!) with very tight tolerances across lots of variables, and considerable compositional diversity (Nikon isn't melting just one glass, it's melting quite a few, to do clever things with dispersion), there are so many variables that you can't really automate everything.

(As a glass melting nerd, I'd really love to see all of the proprietary information that they left out - but I guess that's why it isn't there.)

Curious: would making big pieces, like sliding glass doors, be automated, manual, or a mixture of both?

Entirely automated - if it's glass, big, flat, and smooth, it was almost certainly made via the float glass process, or an equivalently automated continuous-flow system.

Any ideas on the process used to make the glass Apple are using on their new campus buildings?

Is it mainly automated or more manual?

Also does it have any differences like more iron or other additives to lend strength or conversely less to lend clarity?

Sliding glass doors are typically one or two panes of hardened 'float' glass. I put the 'float' between quotes because these days hardly anybody makes float glass by floating molten glass on plates covered with molten tin but instead the glass is cast continuously between rollers. The cooling regime has a large effect on hardness (as does composition), and for extra strength there are other tricks such as lamination.

Nope! The tin-bath process is still dominant these days - the only people rolling glass are small-scale stained glass manufacturers.

For lower volume (or higher tolerance materials), the overflow downdraw method and updraw methods are used, mainly for display glass.

You're right, I had the volume mixed up, thank you for the correction.

But:

> the only people rolling glass are small-scale stained glass manufacturers.

What about:

- the glass used for solar panels

- the glass used for wire bonded glass

- patterned glass

AFAIK those are all made using rollers.

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