A better handover between purchasing and engineering

Engineering knows the application. Purchasing places the order. Between those two facts there is a handover, and it is usually a forwarded email with "please order these" on top.

What gets lost in that gap is always the same thing: which parts of the specification are constraints and which are preferences. Purchasing cannot tell from the outside, so either everything becomes negotiable or nothing does.

Six lines

Line 1 - exact model designations - One per line, with quantities. Not descriptions.

Line 2 - the constraints - The values that must not change: cylinder thread, outlet designation, service pressure, bore. Say explicitly that these are fixed.

Line 3 - the preferences - Finish, handwheel style, packaging. Say explicitly that these can flex.

Line 4 - what is still open - Anything engineering has not confirmed. Purchasing needs to know not to treat it as settled.

Line 5 - who answers technical questions - A name. Suppliers will have questions and the round trip through purchasing costs days.

Line 6 - what a substitution would require - "Any alternative model needs engineering sign-off before ordering" prevents a well-meant swap arriving as a surprise.

The line that matters most

The line that does the most work is the sixth, because substitution is where the expensive mistakes live. A supplier who cannot supply the exact model will often offer something close, and "close" is a judgement only the person who knows the application can make. Writing the rule down once means nobody has to make it under time pressure.

And one line back

Going the other way, engineering benefits from one line back: which supplier was used and what the lead time was. It is the difference between specifying something available and specifying something theoretical.