Re: [CAD_CAM_EDM_DRO] fibre reinforced part casting

Hi Graham:
How many?
How complicated?
These kinds of parts are best injection molded if you need best possible
physical properties.
A moderately glass filled polycarbonate or similar engineering resin is
tough as hell when molded.
Knocking together a simple mold is often not a big investment...I've built
tooling like this all my working life, and a prototype or low volume tool
can often be knocked out for a couple of thousand bucks.
Make a thousand parts and the tool amortization becomes a couple of bucks a
part.
Casting them in RTV silicone is a very poor second best if you need
dimensional stability and good physical properties, but it does work.
Problem is, you'll spend a good bit of time or money or both on that process
too, and the cycle time per part is so much longer that your productivity is
severely constrained.
If I build a quick and dirty in-house tool for molding, I'm usually
competitive at around 250 parts, compared to RTV silicone, and if I build a
REAL rude and dirty mold, I can compete at 50 parts or less.
If you're comfortable with machining and have a good eye for detail, it
ain't rocket science to roll your own.
There are some things you definitely need to know so you build a safe and
effective tool...the main one being that the forces involved are
huge...20,000PSI injection pressure at times, and tens or hundreds of tons
of clamping pressure.
Best path forward if you're interested in doing it this way, is to go to a
local molder and see if they run MUD sets.
This saves you the effort and cost of building a mold base.
They'll give you a set of inserts so all you need to do is cut the cores and
cavities and do the fitting and finishing.
Not bad at all if you know what you want and are handy with a mill.
Cheers

Marcus