What a complete manufacturing package includes

A contract manufacturer builds exactly what your files say. When the files are incomplete or disagree with each other, the build stops while someone asks questions, or worse, it continues while someone guesses. Quotes come back with assumptions buried in them, and two manufacturers quoting the same project end up quoting different products.

A complete manufacturing package fixes that. It is the set of files that lets a board fab and an assembler quote, build, program, test, and ship your product with no information that lives only in an engineer’s head. This article covers what goes in it, the gaps that cause the most trouble, and how to release it so it stays consistent. For the wider move from prototypes to volume, see From prototype to production.

What goes in the package

• Board fabrication

  • Gerber X2, ODB++, or IPC-2581
  • Drill files
  • Stackup and impedance
  • Fabrication drawing and notes
  • Test netlist

• Assembly

  • BOM with part numbers and alternates
  • Pick-and-place data
  • Assembly drawing
  • DNP and polarity notes
  • Paste layers

• Design reference

  • Schematic PDF
  • Board 3D model
  • Known deviations

• Mechanical and box build

  • Enclosure drawings and models
  • Cable and harness drawings
  • Box-build steps
  • Hardware and torque

• Firmware and programming

  • Release images with checksums
  • Programming procedure
  • Serial numbers and keys

• Test

  • Test specification
  • Fixture requirements
  • Pass and fail limits
  • Records to keep

• Labels and packaging

  • Label artwork and placement
  • Serial number format
  • Packaging and contents

• Revision control

  • One revision for the release
  • Revision history
  • Change process

Board fabrication

The board fab needs to know exactly what to make:

• Layer data, as Gerber X2, ODB++, or IPC-2581. Older Gerber files (RS-274X without attributes) still work, but they carry no layer function, so the fab has to work out which file is which. The newer formats carry more of the design intent with them.
• Drill files, with plated and non-plated holes clearly separated. The common Excellon drill format has no field for plating, so it is usually handled with separate files.
• Stackup and impedance requirements: layer count, copper weights, dielectric thicknesses or total thickness, and which traces need controlled impedance, with target values, tolerances, and reference layers, and whether the fab may adjust trace widths to hit them.
• A fabrication drawing or notes: material, finish, solder mask and silkscreen colors, the IPC performance class (IPC-6012 for rigid boards, IPC-6013 for flex), board outline tolerances, and anything unusual such as via filling, edge plating, or castellations.
• A test netlist in IPC-D-356 if you send Gerbers, so the fab can electrically test the bare boards against your design rather than against its own reading of the copper. ODB++ and IPC-2581 already include the netlist.
• Panel requirements: whether you supply the panel design or the fab and assembler create it, plus fiducials, tooling holes, and how boards break out (tabs or V-score).

Assembly

The assembler needs to know what goes where, and which way around:

• The bill of materials (BOM), with reference designators, quantities, the manufacturer and manufacturer part number for every line, and approved alternates. A distributor’s stock number on its own is not enough; distributors change their numbering and stock, and the assembler may buy elsewhere.
• Pick-and-place (centroid) data: position, rotation, and side for every part, in the same units and origin as the board data.
• Solder paste layers and any stencil requirements: stencil thickness, step stencils, or aperture changes for fine-pitch parts and thermal pads, if the default openings will not do.
• Process and material requirements: lead-free (RoHS) or leaded assembly, and any moisture-sensitive parts that need special handling.
• An assembly drawing showing part locations, polarity marks, pin 1, and anything the machine data does not cover: hand-soldered parts, adhesive, conformal coating keep-outs, or heat sinks.
• Do-not-populate (DNP) handling that agrees everywhere. A part that is DNP in the BOM but present in the pick-and-place file can easily get placed.
• Polarity and orientation notes for diodes, electrolytic and tantalum capacitors, LEDs, connectors, and any part whose pin 1 marking varies between vendors.
• The IPC-A-610 acceptance class you expect, so inspection is held to a stated standard.

Schematic and design reference

Include the schematic as a PDF. Assemblers and test engineers use it to diagnose failures and answer their own questions. A 3D model of the assembled board helps the mechanical and box-build side. List any known deviations, such as rework, patch wires, or parts that differ from the schematic, so nobody discovers them on the line.

Mechanical and box build

If the manufacturer builds more than the board, it needs enclosure drawings and models, cable and harness drawings, every piece of hardware with its part number, torque values where they matter, and step-by-step box-build instructions with photos or exploded views. Gaskets, labels, and light pipes are easy to leave out of the BOM because nobody draws them on the schematic.

Firmware and programming

Provide the released firmware images, named with their version and a checksum, and a written programming procedure: which tool, which connector, what order if there are several processors, any fuse, option-byte, or read-protection settings, and how to confirm the load worked. If each unit gets a serial number, a MAC address, calibration data, or security keys, say where they come from and how they are recorded. Keys and credentials need their own secure process. See Designing connected products for EU and UK cybersecurity rules.

Test

A test specification tells the manufacturer what “working” means: what to test, the pass and fail limits, and what records to keep for each unit. If a test fixture is needed, describe it: test points, power, the interfaces it drives, and the software it runs. Test points designed in early make this much easier, which is one of the things a design review should check. Designing for production test covers the board, firmware, and process side.

Labels and packaging

Include label artwork and placement, the serial number and date code format, regulatory markings, and packaging: box, inserts, what ships in the box, and how units are packed for shipping.

Revision control and changes

Every file in the package carries a revision, and the package as a whole has one. Include a short revision history, and agree with the manufacturer on how changes will be made: a written engineering change order (ECO) that says what changed, why, which units it applies to, and what happens to stock and work in progress.

Common gaps

These are the problems that most often hold up a quote or a build:

• Files at different revisions. The BOM is from last week, the Gerbers from today. The manufacturer cannot know which one is right.
• BOM lines with no manufacturer part number, or values only (“10k, 0402”) with no tolerance, voltage rating, or dielectric.
• No approved alternates, so every shortage becomes a phone call and a delay.
• Pick-and-place data that does not match the BOM: missing parts, extra parts, DNP parts left in, or rotations that disagree with the footprint library.
• Impedance requirements implied but not stated, so the fab builds a standard stackup.
• Fab notes that contradict the files, such as a thickness or finish that disagrees with the stackup.
• Missing programming or test instructions, so the boards are built but cannot be finished.
• Changes sent as email attachments rather than as a new release, so nobody is sure what the current design is.

Many of these also show up on a first prototype build. Before your first board spin covers getting that first order right.

How to package it

Release the package as one versioned set: a single archive or folder, named with the product and the release revision, holding every file listed above. Every file inside carries that same revision, in its title block, file name, or both. Include a short readme that lists the contents and states the revision, the date, and who to ask.

Keep the released set read-only. If something needs to change, issue a new revision with a note on what changed, rather than replacing a file inside the old one.

Make it repeatable

A package assembled by hand before each release tends to drift: an output setting changes, a file gets regenerated from the wrong revision, a DNP list gets edited in one place but not another. Good tooling and a defined release process remove most of that risk:

• Generate the outputs with a script from the design tool, so every release uses the same settings and comes from the same tagged source revision.
• Run checks before release: design rule and electrical rule checks pass, the BOM and pick-and-place data agree, every BOM line has a manufacturer part number, revisions match across files, and parts are still active and available.
• Keep the design in version control and tie each release to a tag, so you can always rebuild exactly what the manufacturer has, including years later, when a part reaches end of life or a field problem needs a fix.

Ask your manufacturer to review the package before the first build, too. Their questions will show you what is missing while it is still cheap to fix.

The release to manufacturing checklist is a printable list of what to include and confirm.

If you want help building a manufacturing package or a release process for your product, get in touch.