Molding a mold for a two sided part

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Molding a mold for a two sided part

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Shinobiwan	Shinobiwan posted 12 Years Ago HOT Topic Details
Group: Forum Members Posts: 14, Visits: 97	Hi guys, I'm having some difficulty figuring out the best way to mold a two sided part. I should add that I'm completely new to this! What I plan to do is machine a master on the CNC out of 100mm Polyurethane board and then make a mold box, placing the master in this, and filling with addition cure silicone rubber. I should add that this is a large part measuring 950x180x100mm. I'm not sure what shore rating silicone to use for this. I'm guessing the 40 Shore A that EC supply isn't too soft for such dimensions, especially since it'll be supported with a box? I'll be needing around 17kg for the mold so want to get it right since it'll be an expensive mistake if not. The main problem though is figuring out how to get the rear side detail into the casting without trapping lots of air(some air is fine since this face is hidden when assembled) or distorting the flat rear side portion of the cast part(very important as this is the mounting surface). The way I've tackled it at the moment is to level fill the mold with the casting resin and that will form a guide for the rear. I guess I could leave out the rear details but that'll mean throwing it on the CNC and wasting resin. Would much rather do it in one shot to save time and money. I've attached the front and rear views of the part along with the first half of the mold but I would be grateful for suggestions on how to tackle the second half of the mold. Front side of the part: Rear side: And the first half of the mold: [/img] That's a lot of talk so I'll pick out the questions to be clearer: Is 40 shore A addition cure silicon a good choice for a 950x180x100mm size part. What distance should I allow for around the part and the mold box ie. the void to be filled with silicone. The mold will be supported within a 5 sided box. What would be the best strategy for making the mold in order to capture both the rear and front details without significant pockets of air Using a filler with my resin can I expect to significantly increase the mass? At the moment its around 1.1g/cc Ideally I'd like to aim for 1.5-1.7g/cc. Many thanks Ant Edited 12 Years Ago by Shinobiwan
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