manufacturing_handoff v1.0.0

name: manufacturing_handoff description: "Hand a finished design to a manufacturer so the first production run matches the drawing: build the handoff package with a controlled BOM and approved alternates, run a drawing and tolerance review that catches ambiguous callouts and failing stack-ups, issue an RFQ that forces comparable bids, compare bids on landed cost after a compliance pass, and agree a first article inspection plan with acceptance criteria before parts arrive. Use when releasing a design to a shop or contract manufacturer, preparing an RFQ package, reviewing supplier quotes, or setting up first article or PPAP approval for a new or revised part."

Manufacturing Handoff

Purpose

Move a design from the designer's files to a manufacturer's floor with no gap between what was designed, what was quoted, and what gets inspected. The handoff controls four failure points that cause most first run disasters: a BOM a buyer cannot order from without guessing, a drawing two competent shops would read two ways, bids that price different parts and get compared as if they were the same, and acceptance criteria argued about after parts arrive instead of agreed before they are made.

The method draws on ASME Y14.5 for dimensioning and tolerancing, AS9102 practice for first article inspection structure, AIAG PPAP where automotive programs require it, and ISO 9001 design output and production control discipline. Scale the paperwork to the risk. A bracket for internal use needs the same checks in shorter form, not a different logic.

Workflow

1. Freeze the design at a named revision. One revision governs the drawing, the model, the BOM, and every quote. State in writing which governs if the model and the drawing disagree. Nothing quotes, cuts, or inspects against an unnamed or mixed revision.
2. Build the package manifest. List part number, revision, governing standard with its edition, units, quantity, and every file with its revision. Run bin/handoff.py check on the manifest and clear every error before the package leaves. Template fields are in the manifest example at assets/examples/manifest-good.json.
3. Complete the BOM. Every line carries item, description with the controlling specification, quantity, source (manufacturer part number for bought parts, drawing and revision for made parts), and a critical flag where a wrong part stops the build. Rules in references/bom-and-rfq.md.
4. Settle alternates before quoting. Each alternate gets a recorded status from someone with design authority: approved, approved for a named use, pending, or rejected, with fit, form, function, material, and compliance checked. An alternate with no status does not ship and does not get quoted as equivalent.
5. Run the drawing and tolerance review. Work the full checklist in references/drawing-review.md: governing standard and edition, completeness, measurability, GD&T frame and datum sanity, general tolerance coverage, and an ambiguity pass that reads the drawing as a stranger who gets paid per part.
6. Run every closing stack-up at worst case. List each chain that closes a gap, fit, seal, or clearance. Run bin/handoff.py stackup with the requirement as --require-min or --require-max. A worst case failure is a design failure: fix the drawing, reissue at a new revision, and only then quote. The worked catch is in references/worked-handoff.md.
7. Issue one RFQ package to every bidder. Same files, same day, same response form (assets/rfq-response-form.md), with an exceptions field that forces every deviation, exclusion, and assumption into the open. Answer bidder questions in one written addendum to all bidders. A drawing error found during quoting gets fixed and reissued to everyone at a new revision.
8. Compare bids in two passes. Compliance first: set aside any bid on the wrong revision, material, finish, or an unapproved alternate. Money second: run bin/handoff.py bids to rank landed cost per unit, with tooling, shipping, and other one time charges spread over the quoted quantity. Then weigh lead time, exceptions, included inspection evidence, payment terms, and tooling ownership, and record the decision in one paragraph attached to the purchase order.
9. Agree the first article plan before production. Use assets/fai-plan-template.md and references/fai-plan.md. State sample count, how samples are picked from a real production run, the characteristic list (default: every design characteristic, including drawing notes), material and process evidence, acceptance criteria, deviation authority, and whether production holds until approval. Where AS9102 applies, use its three form structure. Where a customer requires PPAP, build that package instead and do not substitute one for the other without written customer agreement.
10. Close the handoff with a record. File the manifest check output, stack-up CSVs and results, the bid comparison and decision paragraph, the winning quote, and the approved FAI plan with the purchase order. On any later design, process, tooling, source, or location change, reopen the affected steps and agree a delta FAI before the changed process ships parts.

Output Contract

• Package manifest: part number, revision, governing standard with edition, units, quantity, file list with revisions, BOM lines, completed checks, and FAI plan summary. bin/handoff.py check reports zero errors.
• Drawing review record: every finding marked on a drawing copy, its resolution, and the revision it landed in. Open findings block release.
• Stack-up record: one CSV per closing chain with nominal, worst case minimum and maximum, and the requirement verdict. A failing worst case has a design fix attached, never a waiver by optimism.
• Bid comparison: compliance result per bid, landed cost per unit at the order quantity from bin/handoff.py bids, exceptions listed, and a decision paragraph naming the winner and why the others lost.
• FAI plan: sample count and selection method, characteristic list, evidence required, acceptance criteria, deviation authority, and hold or interim approval terms, agreed in writing before parts arrive.
• Purchase order trail: the order references the winning quote, the drawing and BOM revision, the FAI requirement, and the delivery terms, so receiving inspection compares parts against documents, not memories.

Operating Rules

• One revision rules the whole package. Mixed revisions are the single most common handoff defect, and the manifest check exists to catch them.
• Worst case decides. A statistical stack view can support a recorded risk decision on a measured, high volume process. It never overrules a worst case interference on its own.
• A low bid for a different part is a bid for a different part. Compliance against revision, material, finish, and approved alternates comes before any price ranking.
• Headline unit price never wins alone. Tooling, shipping, and one time charges are part of the price, spread over the real order quantity.
• Alternates are design decisions. No silent swaps for price, availability, or shop preference, on any line, critical lines least of all.
• Acceptance criteria exist before parts exist. Sample count, characteristics, evidence, and deviation authority are agreed in writing while there is still time to change them cheaply.
• First article samples come from the production process: production tooling, settings, operators, and documentation. A hand finished sample validates nothing about production.
• Report every measurement taken. Remeasuring until a part passes and reporting only the last value turns inspection into fiction.
• A failed FAI or a process change triggers a delta FAI on the affected characteristics. Installing a fix is not the same as proving it.
• Verbal clarifications do not change drawings, quotes, or criteria. If it matters, it goes in writing to every affected party at a stated revision.