How does fumed silica attain a panel shape when used in vacuum insulated panels?

[Jonah Nevi]

VIPs are shaped like thick rectangles (fairly-flat boxes, cuboids), for example 20 mm x 400 x 600 mm. If manufacturing started with a sheet of styrofoam - a thick rectangle - I would not be surprised that the VIP has the same shape. In videos I've seen* of vacuum-packing loose powders, the result is not panel-shaped. (Fumed silica is not technically a powder, but for the purposes of this question I think I can say it's powder-like.)

I know the vacuum-sealing makes it retain "a" shape, but how does it attain the panel shape?

Do the vacuum chambers include flat plates that physically shape the powder inside their envelope before/during the vacuuming? I've seen many types of vacuum chambers, but none include plates for shaping the contents. How does fumed silica attain a panel shape when used in vacuum insulated panels?

* Video of powder being vacuum-sealed in a vacuum chamber, not resulting in a panel-shaped thick-rectangle: youtube.com/watch?v=2eES_QB1bOM?t=90. (The same process is repeated three times. Just see the first - they're all the same.)

 

[Compositepro]

The powder must molded to shape using a mold. The flat panel surfaces are usually used as the mold surfaces. An appropriate process must be used to compact the powder to shape until it solidifies.

 

[Jonah Nevi]

Thanks. So the powder is poured into the envelopes (metallized film), placed into a mold, and another part or parts of the mold then surround it all, pushing it into the target shape, and then part or all of that mold is put completely inside the vacuum chamber. Alright - I think that solves the mystery. Thanks. I had assumed the shaping happened inside the chamber, but there is no need for that.