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Why do companies create their own part numbers for electronic components?

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philby:
I’ve worked at a few Electronics companies and, with the exception of my current company, they have always created their own unique part numbers for components. For Example, a 1k resistor might be assigned the code RES001K0 as opposed to the manufacturers code of XHE0010TJNM862.

What is the logic behind assigning new part numbers that are unique to your company to the electronic parts you buy and use in your designs?  I’m thinking about putting forward a proposal that we change over to using an internal numbering scheme.

My reasons
-Part numbers can be made shorter, logically grouped together depending on component type and easier to remember.
-If a component has supply problems or is made obsolete, the manufacturers part number is not trapped in BOM’s and need to be updated in multiple locations.
-If a component is made obsolete the old part numbers are not trapped in the schematic component parameters.
-Makes specifying multiple sources easier.

Any other reasons anyone can think of? I'm open to criticisms of the reasons I've listed. Can anyone recommend a good (interesting if possible) book on inventory management?

miguelvp:

--- Quote ----Makes specifying multiple sources easier

--- End quote ---

This, but usually you can still search by manufacturer's part number, specially nowadays since if they didn't they wouldn't show up on google searches and all those spider crawlers or whatever they are called now.

Dago:

--- Quote from: philby on June 10, 2015, 09:41:17 am ---I’ve worked at a few Electronics companies and, with the exception of my current company, they have always created their own unique part numbers for components. For Example, a 1k resistor might be assigned the code RES001K0 as opposed to the manufacturers code of XHE0010TJNM862.

What is the logic behind assigning new part numbers that are unique to your company to the electronic parts you buy and use in your designs?  I’m thinking about putting forward a proposal that we change over to using an internal numbering scheme.

My reasons
-Part numbers can be made shorter, logically grouped together depending on component type and easier to remember.
-If a component has supply problems or is made obsolete, the manufacturers part number is not trapped in BOM’s and need to be updated in multiple locations.
-If a component is made obsolete the old part numbers are not trapped in the schematic component parameters.
-Makes specifying multiple sources easier.

Any other reasons anyone can think of? I'm open to criticisms of the reasons I've listed. Can anyone recommend a good (interesting if possible) book on inventory management?

--- End quote ---

What if there are identical manufacturers codes since there is no guarantee they are unique? With your own internal codes you can guarantee the codes are unique.

philby:

--- Quote from: Dago on June 10, 2015, 10:39:13 am ---What if there are identical manufacturers codes since there is no guarantee they are unique? With your own internal codes you can guarantee the codes are unique.

--- End quote ---

That's a good one thanks.

Tandy:
The reasons we use our own numbers are...

The part numbers help easily identify the category of the product, i.e semiconductors starting with 276 and resistors 271. Back when there were Tandy stores that meant that those products could be found on a particular display stand in the store. We use this same method for locating parts in our stock rooms. Part numbers like PIC16F232C and ATMEGA328P give no indication of where they are stored and to a non electronics engineer/enthusiast gives them no clue what the part is. So they would have to look on the computer to see what bin, tray or shelf the item is in. It is easier to know that (276-006) 276 is the semiconductor section 006 is near the beginning of the rack of semiconductors and 276-9000 somewhere near the end. (Example random made up part numbers not actual parts.).

Partly we have maintained the same scheme for historic reasons as the part numbers being used from as far back as the 1970s means that there are a lot of projects and even books (Forrest Mims for example) that reference Tandy/Radio Shack part numbers so people are using those part numbers to find parts.

A standardised part number makes printing barcode labels easier as the part number has a fixed maximum length so that we can be sure that it fits on a standard sized label.

The large distributors that act as agents for manufacturers for example stocking the same 2N2222A transistor from 6 different semiconductor manufacturers each with their own part numbers for example ON semiconductor P2N2222AG and Fairchild PN2222ATA are functionally the same part. We do the opposite however, in that we stock only 1 2N2222A TO-92 type transistor (276-2009) that could be from a number of different manufacturers. It might sound strange to an experienced person but people are often bamboozled by doing a search and being given 20 variations of the same part, not quite sure if there is some reason that they should choose one of them and what if they choose the wrong one. Instead if someone builds a circuit using our part number 276-2009 they can always build the same circuit even if the manufacturers change part numbers. A classic example is that many manufacturers changed their part numbers to indicate a change to RoHS compliant versions. Obviously that was important to engineers who had to be certain that they were including RoHS compliant parts in their designs but the change in part number just added confusion to most hobbyists. So we just continue to use the same 276-2009 number for the RoHS version so that the hobbyist doesn't need to worry about it.

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