On Mon, May 4, 2015 at 6:00 PM, Luke Kenneth Casson Leighton lkcl@lkcl.net wrote:
I imagine that this would be adapted to more scalable processes once prototyped, however, which would infuriatingly eliminate some of the precision issues experienced during prototyping. Or would you first go through an iteration or two of higher-specification 3D printing first?
right. ok, the plan is as follows:
- phase 1: get 3d printed parts working (as +ves)
- phase 2: split all parts into two -ves
- each 1/2 part will be subtracted from a "block"
- this "block" will fit inside a metal container
- the two 1/2 -ve parts will be fitted inside the metal container
- low-viscosity injection mold plastic will be used to create a prototype part
so *right from the start* i have to design each part so that it can *either* be 3d-printed (as a +ve part) or that it can be split into two -ve halves.
these two halves will fit together, creating an inner space that can be filled with molten plastic... *but*, the tricky part is that it has to be possible to remove the two halves without destroying the plastic inside it.
so, having an inner space that goes round a corner is not possible to do, because at least one of the halves of the mold will be stuck. the two halves have to come out of the plastic *straight* - no overhangs are allowed.
i don't entirely know if this is ok, but i am counting on it being possible to pull one of the mold halves out at one end first, followed by the other. the reason is because i have some screw-holes and insets which i am *hoping* will not be destroyed or damaged when one half of the mold is pulled away from the plastic.
... we shall have to see!
l.