[Arm-netbook] video of laptop casework demo available

[Paul Boddie]

On Monday 4. May 2015 19.00.22 Luke Kenneth Casson Leighton wrote:
> 
>  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

You're braver than I thought. ;-)

>  phase 3:
> 
>  * the two 1/2 -ve parts will be printed out on flash-thermal resin (on a
> DLP) * the two 1/2 -ve  parts will then be flash-cast to metal.
>  * the resultant 1/2 *METAL* parts will then be used for *production*
> injection molding.
> 
> the reason for using high-accuracy thermal resin to cast the molds in
> metal is that - i hope - they will be much more accurate, so will not
> require polishing.
> 
>  if they *do* require polishing (i.e. not look good enough) then what
> i will do instead is investigate some casting methods that give the
> cast parts a "sandy surface" look, meaning that any blemishes simply
> won't show up as significant.

I think Bunnie had some interesting/amusing things to say about surface 
blemishes when they were making the moulds for Novena:

https://www.crowdsupply.com/kosagi/novena/updates/1330

>  $USD 20k on polished injection molds when they're only going to last
> 2 to 3 thousand units before they wear out due to abrasion - it's
> silly.  there has to be a better way.

A while back, I became interested in these matters and surfed around looking 
at UK-based companies offering injection moulding services. Maybe I should dig 
some of those links out and see if there are any collaborative opportunities. 
Interestingly, I think one of them was actually publicly-owned (by a local 
council) and was technically a non-profit.

Paul