25:
135:
82:
538:", "with the holes not yet drilled", "intentionally oversize by 0.01 mm (0.00039 in)", or any of countless other modifications. The intent is usually that the feature in question (such as holes not yet drilled, or paint not yet sprayed) will be added at a higher assembly level; or that maintenance workers in the field will choose from a kit of undersize and oversize parts (such as bushings) in order to achieve a certain fit (sliding fit, light press fit, etc.).
554:, such as the fuselages and wings of aircraft, the hulls of ships and boats, and the bodies of cars and trucks, require matched pairs of parts that are identical, or nearly identical, except for being mirror images of each other. (For example, the left and right wings of an airplane, or the left and right fenders or doors of a car.) Often these related parts are designated
627:
Although this "blending" of part designs could happen very informally in a non-mass-production environment (such as an engineering lab, home business, or prototyping toolroom), it requires more forethought when the concerns are more thoroughly separated (such as when some production is outsourced to vendors). In the latter case, a new part definition, termed a
631:(because its definition synthesizes features from various other parts), is created. Ideally it is then formally defined with a new drawing; but often in the imperfect reality of the business world, to save time and expense, an improvised TPD will be prepared for it consisting of several existing drawings and some notes about which features to synthesize.
122:, pan head, Phillips". In this example, "HSC0424PP" is the part number. It may be prefixed in database fields as "PN HSC0424PP" or "P/N HSC0424PP". The "Part Number" term is often used loosely to refer to items or components (assemblies or parts), and it's equivalent to "Item Number", and overlaps with other terms like
343:, that is usually used; but the word "dash" is firmly established in the spoken and written usage of the engineering and manufacturing professions; "dash number", not "hyphen number", is the standard term. This comes from the era before computers, when most typographical laypeople did not need to differentiate the
622:
that often exists in production, in which the maker of each part (whether an in-house department or a vendor) does not have all the information needed to decide whether any particular small variation is acceptable or not (that is, "whether the part will still work" or "whether it will still fit into
626:
However, a challenge to this paradigm (of perfectly frozen part definition) is that sometimes it is necessary to obtain a part that is "mostly like" part A but that also incorporates some of the features of parts B and C. For example, a new variant of model of next-higher assembly may require this.
362:
Another widespread tradition is using the drawing number as the root (or stem) of the part number; in this tradition, the various dash-number parts usually appear as views on the self-same drawing. For example, drawing number 12345 may show an assembly, P/N 12345-1, which comprises detail parts -2
526:
It is a common concept in many corporations to add certain suffixes beyond, or in place of, the regular dash numbers, in order to designate a part that is mostly in conformance with the part design (that is, mostly "to print"), but intentionally lacks certain features. The suffixes are usually
162:
of that part design. In other words, a part number identifies any particular (physical) part as being made to that one unique design; a serial number, when used, identifies a particular (physical) part (one physical instance), as differentiated from the next unit that was stamped, machined, or
574:, or -LH and -RH part number suffixes. It is also not uncommon to show only one of them on the drawing, and to define the symmetrical counterpart simply by stating that it is "opposite". Common notations include "left-hand shown, right-hand opposite" or "-1, LH (shown); -2, RH (opposite)".
311:, which normally includes digits and dashes, and is operated one-handed, leaving the other hand free. Other benefits: people find numbers easier; in a warehouse, one can store products in numeric order (for example, in an aisle, numbers can increase from one end to the other).
306:
Non-significant part numbers are easier to assign and manage. They can still have some structure, such as a numeric category followed by a sequential number. Eg: 231-1002 (2=Hardware 3=Screw 1=Phillips, 1002 = sequential number). This enables more efficient data entry, using a
195:
of that part do. This is especially common for catalog hardware, because the same or similar part design (say, a screw with a certain standard thread, of a certain length) might be made by many corporations (as opposed to unique part designs, made by only one or a few).
113:
of a particular part design or material used in a particular industry. Its purpose is to simplify reference that item. A part number unambiguously identifies a part design within a single corporation, sometimes across several corporations. For example, when specifying a
293:
In a non-significant part numbering system, part numbers are assigned in some other fashion, such as sequentially or arbitrarily. For example, a screw may have the part number "1002", which may not tell the user anything about its thread size, shank length, or
623:
the assembly" interchangeably). The sizes of fillets and edge breaks are common examples of such details where production staff must say, "it may easily be trivial, but it could possibly matter, and we're not the ones who can tell which is true in this case".
324:, and they are a common way of logically associating a set of detail parts or subassemblies that belong to a common assembly or part family. For example, the part numbers 12345-1, 12345-2, and 12345-3 are three different dash numbers of the same part family.
244:
The U.S. government, and most especially its
Department of Defense, has standardized various part numbering systems over the decades for it and its suppliers to use, such as the AN (Army-Navy) and MS (Military Standard) hardware classification and numbering
213:
The business using such a screw may buy screws from any of those manufacturers, 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
302:
In a company, significant numbering systems help identify an item from its code rather than from a long description. However, variations can arise when codes are used by other companies, which may be your distributors, and can cause confusion.
371:
Some corporations make no attempt to encode part numbers and drawing numbers with common encoding; they are paired arbitrarily. In other numbering schemes there is no separate drawing number, the drawing simply reuses the part number.
380:
Often more than one version of a part design will be specified on one drawing. This allows for easy updating of one drawing that covers a family of parts, and it keeps the specifications for similar parts on one drawing. For example:
232:
There are also some national and industry-association 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:
363:("dash two"), -3, -4, -8, and -11. Even drawings for which there is currently only one part definition existing will often designate that part with a part number comprising drawing number plus -1 ("dash one"). This is to provide
319:
There is a strong tradition in part numbering practice, in use across many corporations, to use suffixes consisting of a "dash" followed by a number comprising 1 or 2 digits (occasionally more). These suffixes are called
541:
Sometimes the terms "engineering part number" and "manufacturing part number" are used to differentiate the "normal" or "basic" part number (engineering PN) from the modification-suffixed part number (manufacturing PN).
276:, and thus they give 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:
367:
of the part numbering system, in anticipation of a day when it might be desired to add another part definition to the family, which can then become -2 ("dash two"), followed by -3 ("dash three"), and so on.
534:
An example of such a design modification suffix is adding "V" or "Z" to the end of the part number to designate the variant of the part that is purchased "less paint", "less
175:
of P/N 12345 today, and another muffler of P/N 12345 next
Tuesday, you have bought "two copies of the same part", or "two parts", depending on the
268:
In general, there are two types of part numbering systems: significant (a.k.a. "intelligent") and non-significant (a.k.a. "non-intelligent").
259:
provides a codification of fastener specifications in B18.24 Part
Identifying Number (PIN) Code System Standard for B18 Fastener Products.
229:
Therefore, the user devises its own part numbering system. In such a system, the user may use the part number "HSC0424PP" for that screw.
667:) take pains to codify the most advantageous combinations of machine-readable information (MRI) and human-readable information (HRI).
639:
It is common today for part numbers (as well as serial numbers or other information) to be marked on the part in ways that facilitate
586:
is sometimes used to describe a series of parts that collectively make up an assembly or subassembly. This concept is helpful in the
354:
Some companies follow a convention of circling the dash numbers on a drawing, such as in view designators and subpart callouts.
606:
It is common in the engineering of parts, subassemblies, and higher assemblies to treat the definition of a certain part as a
531:, although the encoding systems are usually corporation-specific (and thus cryptic, and of little use, to outsiders).
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maintains the NAS system (National
Aerospace Standards), which is gradually replacing the AN and MS systems.
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applications) when it is useful to think of a certain combination of subparts as "one part" (and thus one
451:
A common application of tabulation of part families is multiple dimensions within a general design, e.g.
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681:
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In a significant part numbering system, the part numbers are assigned intelligently, according to an
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171:, and particular instantiations of those designs, by the same word, "part(s)". Thus if you buy a
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For example, when referring to a "Hardware, screw, machine, 4-40, 3/4" long, Phillips":
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Parametric families of parts, and tabulations of part numbers with parameter values
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it would imply that one manufacturer is acceptable and the other ones aren't, and,
663:. Current revisions of major part marking standards (such as the U.S. military's
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is a 16 digit code to codify the products in a nationally unified manner.
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The
Iranian national classification and codification system known as
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using a part will often use a different part number than the various
695:(European designation and registration system for electronic parts)
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extruded right after it. This distinction is not always clear, as
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well-defined concept, with every last detail controlled by the
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570:) parts. It is a common practice to give them sequential
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User part numbers versus manufacturing part numbers (MPN)
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Manufacturer B uses part number "100-440-0.750-3434-A".
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Manufacturer A uses part number "4-40-3/4"-pan-phil",
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Identifier of a particular part design in engineering
598:) for ordering, production, or billing purposes.
225:for the part numbers of all of the parts it uses.
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358:Relationship of part numbers to drawing numbers
264:Significant versus non-significant part numbers
85:Example of a part number for a microcontroller
167:blurs it by typically referring to both part
142:As a part number is an identifier of a part
209:Manufacturer C uses part number "TSR-1002".
130:The part design versus instantiations of it
590:of engineering and production (such as in
69:Learn how and when to remove this message
618:(TPD). This is necessary because of the
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32:This article includes a list of general
730:"Common Support Data Dictionary (CSDD)"
138:Parts marked with assigned part numbers
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527:"intelligent", that is, they use an
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250:Aerospace Industries Association
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635:Machine-readable part marking
651:. Today's advanced state of
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160:a particular instantiation
682:Manufacturer model number
285:C0424 = "4-40, 3/4" long"
687:Global Trade Item Number
335:terms, it is actually a
772:Product classifications
592:product data management
288:PP = "Panhead Phillips"
53:more precise citations.
699:RETMA tube designation
620:separation of concerns
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126:(Stock Keeping Unit).
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550:Many assemblies with
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614:or its accompanying
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282:S = "Machine Screw"
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665:MIL-STD-130
515:10 mm
464:Dash number
400:Thread size
394:Dash number
351:precisely.
327:In precise
91:part number
51:introducing
756:Categories
741:2021-07-07
716:References
643:, such as
564:right-hand
512:12 mm
509:10 mm
501:8 mm
498:12 mm
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487:8 mm
484:10 mm
481:10 mm
439:20 mm
425:15 mm
411:10 mm
345:characters
296:drive type
111:identifier
34:references
767:Encodings
582:The term
556:left-hand
179:implied.
671:See also
649:QR codes
645:barcodes
445:Philips
431:Philips
417:Philips
339:, not a
245:systems.
239:Irancode
189:business
109:) is an
103:part no.
777:Numbers
536:plating
453:bushing
173:muffler
169:designs
47:improve
689:(GTIN)
562:) and
467:Length
397:Length
349:glyphs
337:hyphen
309:keypad
223:format
144:design
107:part #
36:, but
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177:sense
154:is a
150:), a
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105:, or
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341:dash
331:and
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