User Part numbers or Mfr part nummbers?

[Chuck Hackett]

When working with OpenPnP is it better to work with "Mfr Part Numbers" or "User Part Numbers"?

In the past, my process with the old Quad IVc PnP software (Windows 98!) was to load the Quad with User Part Numbers ("MRSxxxx") because its "Part Number" field was quite limited.

I have a large Excel Workbook that holds all my parts purchases, calculates parts used in a board along with Cost of Good Sold, etc.  It also holds a Mfr Number to User Number cross-ref and additional part meta-data.

I have a C# program that, among other things, takes the BOM and substitutes User Part Numbers for the Mfr Part Numbers in the file.  The output of this gets imported to OpnePnP.

OpenPnP does not have the limitation on Part Numbers so I'm rethinking my approach.

Keeping in mind that multiple Mfr Part Numbers can map onto a given User Part Number (e.g.: there are LOTS of Mfr Part Numbers for an 0805 1k, 1% resistor).  This would indicate that User Number would be best, but ...

When looking at the machine, in addition to the Part Number, it would be nice to have a bit more like "0805 1k, 1% resistor" to know at a glance what is being referred to.

This led me to thinking that maybe the concatenation of User Number and info such as:

"MRS0456 0805 1k, 1% resistor" might be best, or, if i generate the "Board" file I could put the meta-data in the "Comments" (I can't figure out how to get placement "comments" in through the OpenPnP "Import" process).

What approach is best in your experience, and why?

Regards,

Chuck

[Toby Dickenson]

> Keeping in mind that multiple Mfr Part Numbers can map onto a given User Part Number (e.g.: there are LOTS of Mfr Part Numbers for an 0805 1k, 1% resistor). This would indicate that User Number would be best,

We do this.

I can't really imagine any other way. You have some requirements for
what parts get fitted. You come up with some scheme to control those
requirements. You give those requirements a name, called a "User Part
Number". Why would you bother inventing such a scheme then not use it
in openpnp.

> When looking at the machine, in addition to the Part Number, it would be nice to have a bit more like "0805 1k, 1% resistor" to know at a glance what is being referred to.

Our approach is to use a distinct category of "user part number" for
ordinary generic resistors and capacitors. That is, not precision
resistors, not high power, not safety critical, normal tolerance,
where any manufacturer will do. Your example would be part number
R-0805-1k which we use in openpnp and in stock control, and we have
generic baseline requirements to be considered during purchasing of
generic passive components.

All the safety critical resistors etc get a cryptic part number, and
the database records the specific requirements.

Toby

[cdh...@gmail.com]

Toby,

Thank You, you have confirmed my suspicions.

Chuck

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