Volumes of production

High volumes, typically more than 25,000 units.

Unit price vs. capital investment

This high-volume production process is expensive, partly because of the need for two sets of dies. Large volumes are needed to produce economical components.

Speed

Depending on the setup and the component size, extremely high speeds are possible.

Surface

Good surface, which does not need secondary processing such as heat treating.

Types/complexity of shape

The process is capable of producing complex shapes. Powder forging can accommodate a high degree of varying wall thicknesses, which can be as low as 1/25 inch. Undercuts are not possible.

Scale

Similar to drop forging and press forging (for both, see forging, p.187)—think of a spanner or a gear (around 8 inches in diameter) for reference.

Tolerances

Part of the advantage of powder forging is its ability to produce parts with higher tolerances than other forging methods.

Relevant materials

Most ferrous and nonferrous metals. A large number of powder forgings use iron with small amounts of copper and carbon.

Typical products

Engineering components for a range of industries, including automotive parts, connecting rods, cams, hand tools, and transmission components.

Similar methods

Drop forging and press forging (p.187) and compression molding (p.174).

Sustainability issues

Powder forging offers greater precision and less excess material than conventional forging, so requires only minor secondary processing to make more efficient use of energy. It still requires high temperatures to create material flow and this has a large impact on energy consumption and emissions. In addition, over several hundred runs the intense impact pressure between the die and the substrate material can result in greater maintenance requirements.

Further information

www.mpif.org

www.gknsintermetals.com

www.ascosintering.com

Precise-Cast Prototyping (pcPRO^®)

Product	sample components
Materials	polymer resin
Manufacturer	Fraunhofer Institute
Country	Germany
Date	2004

These sample components, shown from both the top and underside surfaces, are an example of the machined CAD-cut details. The cutting lines on the surface are visible, as is the flat cast side.

The Fraunhofer Institute in Germany is one of the world’s biggest research organizations concerned with materials and manufacturing. One method of production that has recently been developed by the institute is precise-cast prototyping.

Precise-cast prototyping (or pcPRO^®) is a method for rapid prototyping that combines casting and milling operations in a single machine. It is a two-stage process, with the first stage involving a milling machine (see p.20) cutting a mold into an aluminum block using information from a CAD file. This mold is filled with a polymer resin. Once the resin has hardened, the same milling machine cuts it to a precise final shape. The essence of this process is that it allows for one side of a product (the molded side) to be replicated exactly each time the mold is filled, but the top (milled) side may be adapted according to the information contained in the CAD file.

A product prototype usually requires numerous adjustments before it is optimized, forcing the modelmaker to start from scratch each time. With precise-cast prototyping, however, changes are only ever made in the CAD data. The main advantage is that for components such as housings for various electrical products, which have one side where the shape needs to be fine-tuned, multiples can be cast using the mold, with only one side being altered with CAD files.

–  Permits the combination of automated and shape-specific manufacturing.

–  Time- and cost-effective.

–  High-quality finish.

–  Limited number of manufacturers offer this method.