glass manufacturing.

Does anyone have experience with manufacturing glassware. I am interested in making kitchen wares and I have no experience with glass. Is it possible to get prototypes? What kind of volume do you need for manufacturing glass? Tooling costs and part costs? It is a big mystery to me.

Any resources would be appreciated.

Thanks, Mark

I have recently had a few glass prototypes made from a family-run glass factory in London. While they do a lot of one-off prototypes for designers and students, they usually take orders from medical and scientific firms.

The price ranges a lot depending on what you want to do. My prototype was about 100GBP, while my friend’s was only 20 GBP.

If you are in London, I can give you the contact. They are great guys to work with.

My experience comes the way of glass shades for lighting. Basically, the manufacturing occurs in two ways: blowing or pressing.

Blowing glass, in a manufacturing sense, requires a two piece mold. It is clamped over a hot piece of glass while air is blown into the glass forcing it to follow the contours of the mold. Think of it like blow molding plastic. While the piece is still hot, but not fluid, the piece is cut off the remaining blob of glass. It can be cut again if needed. The tolerances really vary on this sort of glass. The thickness can vary 3-5mm easily. It follows the mold fairly well though, and depending on your QC, you can have about .5mm tolerance on the outside dimensions.

Pressed glass is where a hot piece of glass is put into a mold, then the mold is pressed together, forcing the molten glass around the inside of the mold. It too can be cut afterwards. Think of it like molding a thermoset plastic. Here, a designer does have control over thickness and outside dimensions. The tolerances are tighter than blown, but because the amount of glass placed in the mold is imprecise and the way the glass will shrink as it cools, tolerances are not as tight as with other materials. Expect plus or minus .2-.3mm.

Costing. Blown glass is considerably cheaper, at least in China. Tooling costs only a few hundred dollars at most (a glass shade fitting into a 12cmx12cmx12cm box cost us $120 US, if I recall right). Actually production units are fairly cheap too. $1.50-2.00 US for the piece I already described. Therefore, with blown glass, you can go right to manufacturing, there is no reason to try to prototype. Pressed glass is more expensive. Tooling is stronger to take the pressure. Expect around $800-1200 US. Unit costs can also be more, I think something about the same size as I decribe in blown, can cost $3.50+ US in pressed. It’s really a question of where you are using the piece.

Prototyping in pressed glass is not really possible. I would recommend trying a rapid prototype technique (3D printing) or hand making something out of wood/renshape/foam to judge the form. You can also make a RTV mold and pour clear resin in. Once you have your molded piece, if you sand blast it, it will give you a look similar to acid-etched pressed glass.

Let me know if you have any other questions.