How to prepare a product for manufacturing

Create one controlled technical package

Give every file a part number and revision. The bill of materials, drawings and CAD must refer to the same configuration. Separate approved information from reference material so an old sample cannot silently become the production standard.

• 3D CAD in the supplier’s agreed exchange format, plus native files where required.
• 2D drawings for critical dimensions, interfaces and inspection datums.
• Bill of materials with exact grades, finishes and bought-in components.
• Assembly sequence, joining methods and any required fixtures.
• Appearance references for colour, texture, logos and visible surfaces.
• Validation plan, acceptance criteria and an open-issues register.

Design around the selected process

A printable shape may be difficult to mould. An injection-moulded part needs a reviewed strategy for wall sections, draft, parting line, gates and ejection. Ask the toolmaker to identify the process constraints on your specific geometry before release.

For a machined or formed product, the relevant questions differ: access, stock, fixturing, bending or joining may dominate. A DFM review should produce explicit proposed changes and decisions, not just an unexplained “OK to manufacture” stamp.

Spend precision where it protects function

Do not put the tightest possible tolerance on every dimension. Identify the interfaces whose variation can cause failure, then review the complete stack of mating parts. Discuss what can be measured reliably and how.

For a lid and housing, checking each component independently is not enough. Define clearance, alignment and the assembled result. A supplier needs to know whether the priority is a visually even gap, sealing performance or a force-controlled snap fit; those requirements may compete.

Make quality observable

Replace “premium finish” with a reference sample and documented viewing conditions. Distinguish critical functional defects from cosmetic issues and agree how both will be evaluated. For colour, name the reference and the approval method rather than sending only a screen image.

Inspection should be feasible at the intended production rate. If a critical dimension requires a fixture or a functional gauge, include its design, ownership and acceptance in the scope. Sample quantities and test methods should be agreed for the product’s risk and markets.

Run a pilot and release deliberately

A pilot checks the combination of parts, assembly, people and process. Record rejects, rework, assembly time and recurring defects. A hand-built prototype does not show whether a production operator can consistently reach the same result.

Before release, close critical issues, approve the production-intent sample and record the frozen revision. Define how changes after release will be requested, priced, tested and documented. Keep a copy of the approved package outside the supplier’s systems so the product remains maintainable.