Question about Molds: FRN vs Metal

[SpyderEdgeForever]

1 Why does it seem molds for casting and molding metals such as aluminum are cheaper than molds for materials such as FRN? Is it more to do with the nature of the material difficulties, like for FRN you need injection molding and such, or, what?

2 Which are more difficult and easier to design?

One reason I ask is because I have been looking at the history of hand made and factory made knives with molded and cast aluminum handles, and comparing it to the history of molded FRN and polymer, plastic handles, for knives, and I wanted some comparison.

Thank you

[awa54]

I have no idea what molds/casting processes are more expensive, but isn't most aluminum and steel used in knife handles machined from billet, or flame cut or stamped out of strip?

Remember also that a cast metal part can be ground, machined, tumbled and have a surface treatment applied, the FRN basically has to come out of a mold cosmetically and dimensionally perfect.

[demoncase]

1 Why does it seem molds for casting and molding metals such as aluminum are cheaper than molds for materials such as FRN? Is it more to do with the nature of the material difficulties, like for FRN you need injection molding and such, or, what?

2 Which are more difficult and easier to design?

One reason I ask is because I have been looking at the history of hand made and factory made knives with molded and cast aluminum handles, and comparing it to the history of molded FRN and polymer, plastic handles, for knives, and I wanted some comparison.

Thank you

Not sure where you're getting that information from- High pressure casting dies for aluminium and other non-ferrous metals are generally more expensive than FRN moulds

Gravity casting can work out cheaper for non-complex parts, as you aren't having to have a gallery system for the force-injection of a thick fluid of liquid nylon mixed with chopped fibres. Fluid alloys behave more like Newtonian fluids and pour/flow more easily, hence less complex die.

It may be the data your referencing is the moulds used to make sand-dies for aluminium gravity casting- these are quite a bit cheaper than an FRN mould as they don't need all the injectors and galleries. You're just working with sand to make the forms for the final cast.

Here's a handy link for you- Not 15 miles from my front door. http://www.hcmeng.co.uk/high-pressure" onclick="window.open(this.href);return false;