Volumes of production

The process of incremental sheet-metal forming is increasingly well known and is attractive because it offers the possibility of economic production of small batches. It has been used for manufacturing prototype products, including a prototype car made by Toyota. Other applications such as dental prosthetics, where each product must be unique, are also emerging.

Unit price vs. capital investment

The obvious advantage of this process lies in the fact that it allows low-volume production with extremely low tooling and setup costs.

Speed

Typical feed-rates can be up to 2 inches per second, and a typical part will take between 20 minutes and an hour, depending on the surface quality required.

Surface

Depends on the step size between successive passes of the tool. A step size of around 1/250 inch per pass gives an A-class surface, as rated by a car body maker. The surface can also be enhanced by the use of molds.

Types/complexity of shape

Depends on whether or not a die is used, but the parts will always be shell-shaped—although, in the near future, machines will be built with upper and lower indentor tools to get around this.

Scale

While typical components are approximately ¼–½ inch square with an average thickness of 1/25 inch, researchers in Japan are capable of forming parts that range from a fraction of an inch in length up to sheets that are 6½ feet long.

Tolerances

Depend on whether or not a die is used. First-time geometric accuracy can be poor (out by 1/12–1/5 inch), even if the tool path is only creating simple contours from a CAD model. This can be improved, but it involves trial and error. Accuracy is obviously much greater if a die is used.

Relevant materials

A wide range of materials, including a selection of aluminum and steel alloys, stainless steel, pure titanium, brass, and copper.

Typical products

Several applications exploit the potential of this process for one-off production, including the manufacture and repair of car body panels, tailored medical devices and prosthetics, and architectural panels.

Similar methods

Incremental sheet-metal forming has its roots in metal spinning (p.56), but obviously has far greater advantages in terms of rapid prototyping and flexible manufacturing. Another closely linked process is press forming (see metal cutting, p.59).

Sustainability issues

The process eliminates the need for specialized tooling for each component produced, and dramatically reduces material use in mold manufacture and subsequent energy use. Faulty sheets can simply be reworked rather than reprocessed or scrapped, which further minimizes energy use and also allows for easy modification of pre-formed parts. In terms of batch production and prototyping, processing speeds and energy use can be more efficient than in competitive techniques.

Further information

www.ifm.eng.cam.ac.uk/sustainability/projects

8: Finishing Techniques

Sublimation Dye Printing

Vacuum Metalizing

Flocking

Acid Etching

Laser Engraving

Screen Printing

Electropolishing

Tampo Printing

Suede Coating

Hot Foil Blocking

Over-Molding

Sandblasting

i-SD System

In-Mold Decoration

Self-healing Coating

Liquid-Repellent Coatings

Ceramic Coating

Powder Coating

Phosphate Coatings

Thermal Spray

Case Hardening

High-Temperature Coatings

Thick-Film Metalizing

Protective Coatings

Shot Peening

Plasma-Arc Spraying

Galvanizing

Deburring

Chemical Polishing

Vapor Metalizing

Decalization

Pickling

Nonstick Coating (organic)

Nonstick Coating (inorganic)

Chrome Plating

Anodizing

Shrink-Wrap Sleeve

Dip Coating

Ceramic Glazing

Vitreous Enameling