Part number

A part number (or Part#) is an identifier of a particular part design used in a particular industry. Its purpose is to simplify referencing to that part. A part number unambiguously defines a part within a single manufacturer.

For example, when specifying a screw, it is easier to refer to "HSC0424PP" than saying "Hardware, screw, machine, 4-40, 3/4" long, panhead, Phillips".

User Part Numbers vs. Manufacturing Part Numbers (MPN)

A business using a part will often use a different part number than the various manufacturers of that part do.

For example, when referring to a "Hardware, screw, machine, 4-40, 3/4" long, panhead, Phillips":

• Manufacturer A uses part number "4-40-3/4"-pan-phil",
• Manufacturer B uses part number "100-440-0.750-3434-A".
• Manufacturer C uses part number "TSR-1002".

The business using such a screw may buy screws from any of those manufacturer, because each supplier manufactures the parts to the same specification. To identify such screws, the user doesn't want to use any of those manufacturer's part numbers, because

• it would imply that one manufacturer is acceptable and the other ones aren't, and,
• it wishes to use a consistent format for the part numbers of all of the parts it uses.

Therefore, the user devises its own part numbering system. In such a system, the user may use the part number "HSC0424PP" for that screw.

There are also some national initiatives which help producers and consumers codify the product based on a unified scheme to establish a common language between industrial and commercial sectors. For example, Iranian national classification and codification system known as Irancode is a 16 digit code to codify the products in a nationally unified manner.

Significant vs. non-significant part numbers

In general, there are two types of part numbering systems: significant (a.k.a.: Intelligent) and non-significant (a.k.a.: non-Intelligent).

• In a Significant Part Numbering System, the part numbers are assigned intelligently and are an indication of salient characteristics of the component. For example, a screw may have the part number "HSC0424PP".

In this case, the letters indicate characteristics of the component:

• H = "Hardware"
• S = "Machine Screw"
• C0424 = "4-40, 3/4" long"
• PP = "Panhead Phillips"

• In a Non-Significant Part Numbering System, part numbers are assigned in some other fashion, such as sequentially. For example, a screw may have the part number "1002".

Significant part numbering systems are easier to use if you are trying to identify an item though the use of its code inside your company rather than a long description, however many variations can start to appear when the code is used by other companies which may be your distibutors and then people can become confused. Non-significant part numbers are easier to assign and manage. You can still create a structure where you can have a category and then a sequential number e.g. 231-1002 (2=Hardware 3=Screw 1=Phillips then the unique number 1002) This is also more efficient for data entry where using numbers and dashes are part of a normal keypad which means you don't have to use both hands on a keyboard. One other bonus is that people usually understand numbers easier and when you store products in a warehouse you can put items in numerical order. Lower number at one end of an aisle and as you continue the number increases.

Phantom part

The term phantom part is sometimes used to describe a series of parts that collectively make up an assembly or sub-assemby.

See also

• Global Trade Item Number (GTIN)
• Stock Keeping Unit (SKU)

References

• partnumber.com Significant Part Number assignment utility
• Design Chain Associates and BPIC Arguing against intelligent part numbering systems

External links

• Part Number Database
• part-numbering.com Customizable part numbering software for both significant and non-significant systems.