My prototyper is saying that creating a clear hollow model of my design (ala piggy bank or spice shaker) is “EXPERIMENTAL” and that the R&D they put into figuring out how to do it will cost me. I’ve used them before and have had good luck with them, though this was for opaque SLA models.

So, my question is: JUST HOW “EXPERIMENTAL” AND UNKNOWN IS MAKING A CLEAR HOLLOW MODEL? It seems so straightforward to me, but…??? Could use some advice. The prototypers are saying that the part will have to be roto-molded…

REALLY. Why not slipcasting? Are they the same? HELP!

Do you need a crystal clear prototype? You won’t get it in an SLA. If I need really clear bottles (perfume, liquor, etc…) I’ve vacuum formed the front and back and glued them together, or I had the whole bottle CNC’d out of acrylic and then flame hardened. You won’t get a true feeling bottle though. Blow molding it may not be a bad idea if you need/want samples as well.

Hi 10 yr pro,

Thanks for your response.

No, it doesn’t have to be crystal clear, but I am trying to avoid having a seam down the middle and glaring imperfections in the material and form. It is a model that is 4" wide and about 2" tall, and though it’s not overly detailed, the walls are thin and, in that sense, it is somewhat delicate.

I told my prototypers to go ahead and run the SLA piece that will be the positive for anything that comes later. Was this unwise? With vacuum forming, rotoing, or slipcasting, you do need a positive piece first, right?

Sorry, I’m a rookie.

If the walls are very thin, they’ll need to build in a honeycomb structure inside to keep the walls straight, but 2 inches high shouldn’t be a big deal. If they had to, may be they could put in some minimal supports. I’ve had 5 inch, thin walled tubes done (0.040") that came out pretty straight, but not perfect. You’re right on the other processes that they would need a finished (probably polished) 3d part or buck for a mold or vacuum form.

Hope this helps!

It really has, thanks!