Signature Plastics Parts Numbers

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Revision as of 14:08, 11 September 2012 by Mkawa (talk | contribs) (Keycap Families)
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Signature Plastics (SP) keycaps are each designated by an "intelligent part number". These part numbers have historically only been used internally, but for the good of the community, we will be helping Signature Plastics externally document their usage and interpretation, so that orders can be more clearly and unambiguously stated by both parties.

For information on designing legends that are compatible with SP's production processes, see: Signature Plastics Legends

This is a demonstration page to show how the information might potentially be displayed. The markup language is the same as wikipedia (as it runs on the same software). Tables, including CSV tab-delimited tables can be expressed as well as larger more graphical elements.

Inventory Part Numbers

Signature Plastics keeps some number of typically blank keycaps in inventory. These keycaps have 6 digit part numbers.

Part Numbers for 2-Shot Legended Keycaps

Doubleshot keycaps are designated with part numbers by signature plastics in the following way:

  • 14 digit Engineering Part Number (EPU)
  • color codes for part
  • n-digit legend code

EPUs Explained

Example EPU

The 14-digit prefix of an SP 2-shot part number indicates all characteristics needed for SP to select a mold for the second shot of the keycap. That is, the mold for the keycap and mounting stem itself (the initial shot is the legend). These characteristics are (in order) as follows:

  • Keycap family type (DCS, SPH, SA, ...)
  • Mount style (MX, Alps)
  • External description (optional external mold subfamily identifier)
  • Internal description (optional internal mold subfamily identifier)
  • Dimensional description (required mold size identifier in arbitrary units)
  • Row number (refer to row profiles for each family here)
  • Mount description (typically A for 'all mounts for this mold')
  • Mount spacing code (specifies distance between mounts for this mold)

EPU Encoding

Keycap Families

External Description

The 2-digit external descriptor describes the mold subfamily within the keycap family.

Example external and dimensional descriptors

Dimensional Descriptions

The 2-digit dimensional descriptor describes the the number of keycap units in every dimension, fully describing the keytop polygon for a given keycap family and internal and external descriptor set.

Row Numbers

Color Coding

SP's color codes are straightforward 2-3 digit identifiers that specify a very specific colored plastic. Sample chips of these plastics with their corresponding color codes can be ordered from SP. Do not order custom keysets from SP without first ordering a set of color chips for the material that you plan on producing parts in. Color matching in photos is near impossible, so SP cannot provide you with color accurate photos of a material before it is produced.

  • Note that color codes are reused between materials. Hence, there exists both an BFN encoded ABS material as well as a BFN encoded PBT material. However, these two materials are not the same color!

Legend Encoding

SP has an exceedingly large number of legend codes. For the sanity of their sales staff, we will only deal with and recommend dealing with legends that are covered in Signature Plastics Legends.


Consider the following part number: 104U0000A12C00*NN/WA- Q838 - Meaning to production: 10(DCS ABS Family), 4U (Cherry MX Mount), 00 (no additional external information), 00 (no additional internal information), A1 (single space key), 2 (row 2), C (center mount), 00 (no mount spacing required), NN/WA - (Black 2nd shot/keycap body and White 1st Shot/legend), Q838 (legend number for the Q 0.187" tall located in the upper left corner of the keycap). We have over 500,000 legends in our legend library and sadly for me they are not cataloged on the computer, so I have no way of providing you this information 'preorder'. It would however, be exponentially helpful if from here on out I gave you our work orders containing these intelligent part number so re-orders or new orders with the same legends are the same - specifically from a legend standpoint.