Body in white (BIW) is the stage in

automobile manufacturing The automotive industry comprises a wide range of companies and organizations involved in the design, development, manufacturing, marketing, and selling of motor vehicles. It is one of the world's largest industries by revenue (from 16 % such ...

in which a car body's frame has been joined together, that is before painting and before the motor, chassis sub-assemblies, or trim (glass, door locks/handles, seats, upholstery, electronics, etc.) have been integrated into the structure. Assembly involves different techniques such as

welding Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as b ...

(spot, MIG/MAG),

riveting A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite to the head is called the ''tail''. On installation, the rivet is placed in a punched o ...

clinching In metalworking, clinching or press-joining is a bulk sheet metal forming process aimed at joining thin metal sheets without additional components, using special tools to plastically form an interlock between two or more sheets. The process is ...

, bonding and laser

brazing Brazing is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal. Brazing differs from ...

. The term derives from manufacturing practices before steel unibody

monocoque Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, ...

s — when automobile bodies were made by outside firms on a separate chassis with an engine, suspension, and bumpers attached. The manufacturers built or purchased wooden bodies (with thin, non-structural metal sheets on the outside) to bolt onto the frame. The bodies were painted white prior to the final color. A

folk etymology Folk etymology (also known as popular etymology, analogical reformation, reanalysis, morphological reanalysis or etymological reinterpretation) is a change in a word or phrase resulting from the replacement of an unfamiliar form by a more famili ...

for "body in white" is the appearance of a car body after it is dipped into a white bath of

primer Primer may refer to: Arts, entertainment, and media Films * ''Primer'' (film), a 2004 feature film written and directed by Shane Carruth * ''Primer'' (video), a documentary about the funk band Living Colour Literature * Primer (textbook), a te ...

(undercoat paint)— despite the primer's actual gray color. BIW could also refer to when car bodywork would be made of timber - all timber products, furniture, etc., are considered to be "in the white" when at the stage of raw timber before finishing or varnishing. In car design, the "body in white" phase is where the final contours of the car body are worked out, in preparation for the ordering of the expensive production stamping die. Extensive computer simulations of crash-worthiness, manufacturability, and

automotive aerodynamics Automotive aerodynamics is the study of the aerodynamics of road vehicles. Its main goals are reducing drag and wind noise, minimizing noise emission, and preventing undesired lift forces and other causes of aerodynamic instability at high spee ...

are required before a clay model from the design studio can be converted into a body in white ready for production. Factories may offer BIW cars to racers, who then may replace up to 90% of the car with aftermarket parts, and niche manufacturers like

Ruf Automobile Ruf Automobile GmbH (stylized as RUF) is a German car manufacturer. Formerly using Porsche bodies in white to build cars, today they build vehicles on their own bodies and chassis. They also manufacture performance parts for various Porsche m ...

start their cars with BIWs from other makers.

Related terms

A related term in the automotive industry is "body in black". This can refer to a car body that is formed of alternate materials such as composites rather than conventional metal; these composite materials, such as carbon fiber, are black rather than white. "Body in black" can also refer to a step in the design process in which a mock-up of a new car skin is built, in order to perform exacting measurements during the design and pre-production processes.

References

External links

Images and information on body-in-white, Cambridge University
{{DEFAULTSORT:Body In White Automotive engineering This image is from Suzuki Motor Corp vehicle that was displayed in the Australian Motor Show in 2010.