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Something I love about 3D parametric CAD is how a drawing can evolve to be both simpler and better. While my version 2 drawing had about 20 steps, this one is down to nine. No more ribs, no offsets or mirrors in the sketches, no double-revolves and no seams across the mount ads. Printing will be dramatically faster. The quality of the side rails is now the key factor in final mold accuracy (these stabilize it while filling with plaster from the back).
I now draw the simplest repeatable shape: A one-quarter slice. Step 5 cuts the bottle profile from the solid block extruded in step 4. The preceding steps were a sketch of the bottle and block outline and a plane and sketch for the pad. Steps 6 and 7 are the extrusion and corner rounding of the pad cutout (near the rim). The last two steps mirror this quarter upward to create the block and then shell it to hollow the back side.
The drawing is now fully parametrically resizable, I have taken advantage of that to make a stubby bottle test. Neck spline points are now spaced vertically as a percentage of the neck height parameter - set at "70" here. The body and neck heights are separately set now so the full height is now a driven dimension - it is 146 here.
This project is a testament to my wife's patience with me using her kitchen as a mold making shop. Most of the tools I need are there. I nice stable table to run two 3D printers, lots of room and plugins, electrical appliances, utensils and supplies of every type, good lighting. And pleasant company!
I have already poured PMC-746 rubber into 3D printed block molds and have printed and put in place stabilizers to hold the rubber in place. Embeds are in place on both the bottle base and bottom mold (upper right). The flexibility of this rubber is amazing, it make possible extraction of the plaster base, although with difficulty. It also preserves the embossed logo on the foot. This is version 4 (version 5 will have a shallow base piece and modified sliding natches).
Projects |
Beer Bottle Master Mold via 3D Printing
A project that took several years of failures and blind allies and is finally coming together - so much simpler than expected! |
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