I believe injection moulding is used mainly for thermoplastic moulding process.
How It Works
The powder to be used is filled into the hopper of the injection moulding machine.It is then pushed forward by a ram in the machine to the heating cylinder of the injection moulding machine,where the powder will be heated.After heating the powder,it is then forced into a mould and allowed to cool.After some time when the powder must have cooled in the mould,the mould is opened and the moulded part is knocked out.
Sorry I don't think is possible for me to show you the injection mould diagram here,but if you still insist on getting the diagram,look for any polymer text book I believe you will see the diagram there.
As for where to get the raw materials,why not mail the guy untop with his e-mail address to see whether he can be of help.