Many automotive part and assembly manufacturers require permanent identification. They often need the identification code to withstand oil, gasoline, solvents, corrosion, abrasion, as well as painting and finishing operations. Indenting is considered to be the most permanent method for identification, since the mark can only be removed by destroying the surface of the product.

The following is a list of several reasons for permanent identification in the automotive parts industry and some typical applications:

Instructional Identification
Manufacturer & Product Identification
Date Coding
Traceability
Operational Marking

Instructional Identification
Many products are marked to show instruction information. This information may refer to how the product is installed, product and capacity ratings, specifications, or safety regulations.

Manufacturer & Product Identification
To ensure correct replacement parts, a mechanic or service person would rely upon the marking showing the manufacturer and part number. In most instances, this information is dictated and specified by the automotive manufacturer. A specification is provided to the part manufacturer showing the where, how and what the part number identification will be.

For most critical parts, this will be indented if the product is metal or molded if the product is plastic. In either case, this marking is considered permanent. Part number identification will appear on virtually every part assembly in the automobile, such as brackets, door frames, starters, transmission parts, water pumps, drive shafts and spark plugs.

For aftermarket parts, they will also have to include their own part numbers for these replacement parts.

Some manufacturers make an original equipment part, their own aftermarket brand. It is important for this manufacturer to have either interchangeable marking die tooling or a versatile marking machine. Matthews provides both solutions.

Date Coding
Date codes are a good way to track any changes in materials or manufacturing processes, should the need arise to study this information at a later time.

Many manufacturers offer a warranty on their replacement auto parts. Most manufactured assemblies for the automobile require permanent date code marking. There are two commonly used formats for date codes: "month, day, year" and "a year plus Julian". To apply date codes to higher production items, a manufacturer may use a stamping machine, programmable stylus marker, or a laser system.

Machine identification provides a consistent marking depth and registration when compared to hand marking. In the case of a stamping or a roll-marking machine, steel type is placed into holder and changed on a daily basis. The number of characters, as well as size of characters, may be limited based on the marking force of the machine or lens intensity in a laser.

Traceability
True traceability is the newest and most demanding product identification requirement being made by the automotive industry.

One system of traceability is the use of a serial number. It is used to treat every part as unique, so it can be traced.

Time traceability usually requires a computer-controlled marking system. Ink-jet and Laser should be considered for this application, depending on the finishing operations of the part.

Operational Marking
Operational marking is used as a form of internal quality control process. Typically, this involves a color-coded mark that distinguishes very similar parts or indicates that a certain operation has been performed.