Serial Production Is Its Own Project

A medical device that works in the lab is perhaps 60 percent of the way to a device you can sell. The remaining 40 percent is proving that a factory, with different operators on different shifts using different lots of material, produces units identical to the one that passed verification.

That proof is design transfer, and it is a formal requirement, not an operational courtesy. FDA's design controls regulation states plainly that the device design must be correctly translated into production specifications. In practice it consumes six to fourteen months and $150,000 to $800,000 for a moderately complex Class II device, and first-time teams routinely leave it out of both the schedule and the raise.

What Design Transfer Actually Means

Transfer is not sending the factory a folder of STEP files. It is converting design outputs into a complete, unambiguous manufacturing package and then demonstrating that the package produces conforming product.

  • Fully dimensioned drawings with datums, geometric tolerancing where it matters, critical-to-quality characteristics identified, and inspection methods named for each. A STEP file plus a verbal tolerance is the most common transfer defect.
  • A released, controlled bill of materials with approved suppliers and part numbers, not "equivalent" placeholders.
  • Work instructions written at the level of the operator who will actually build it, with photographs, torque values, cure times, and reject criteria.
  • An inspection plan with sampling scheme, gauges, and acceptance limits, including gauge capability studies where measurement error is significant relative to the tolerance.
  • Device master record assembling all of it as the definitive build recipe, kept under change control.
  • Labeling and packaging specifications, including the UDI carrier and the sterile barrier system.

The regulatory framing for all of this is in FDA design controls, and the manufacturing-side obligations in FDA QSR and GMP requirements.

Process Validation: IQ, OQ, PQ

Any manufacturing process whose output you cannot fully verify by inspecting the finished product must be validated. That covers sterilization, sealing, welding, bonding, coating, cleaning, and in practice most molding of critical parts. The standard sequence:

Installation Qualification documents that the equipment is installed to specification, calibrated, and running under defined utilities and software revisions. Typically two to six weeks per process.

Operational Qualification establishes the process window by running deliberately at the edges of each parameter, not just at nominal. This is where you learn that seal integrity fails at the low end of your dwell-time range. Four to twelve weeks, and the phase most often shortened to the program's later cost.

Performance Qualification runs three consecutive production lots at nominal settings with production operators and production materials, demonstrating consistent conforming output. Four to ten weeks.

Two practical rules. First, validate the process you will actually run, on the actual equipment, at the actual site: a validated process at the prototype vendor transfers to nobody. Second, understand the difference between proving the design is right and proving the build is right, which is laid out in verification vs validation. Sterile products carry an additional package covering the barrier system, described in sterile packaging validation.

The Quality System Has to Exist First

You cannot transfer a design into a facility with no quality system. Before the first validation lot runs, the site needs document and record control, training records for every operator on every operation, calibration and preventive maintenance programs, nonconforming product handling, CAPA, complaint handling, and traceability from finished unit back to component lot. Those elements are the substance of ISO 13485.

For a startup the practical question is whether to build this in-house or use a contract manufacturer that already holds it. A qualified medical CM costs 20 to 40 percent more per unit and saves twelve to eighteen months and a great deal of capital. Building your own line makes sense when volumes are high, the process is proprietary, or the margin cannot absorb the CM markup.

Qualifying Suppliers and Subcontractors

Every supplier touching a critical component becomes part of your quality system. Qualification means an audit or documented assessment, a quality agreement specifying notification of any process or material change, agreed incoming acceptance criteria, and first article approval before production shipments. Skipping the change-notification clause is how a molder switches resin grades for cost reasons and invalidates your biocompatibility file without telling anyone.

Molded parts for sterile or patient-contact devices usually add environmental controls, and the practicalities are covered in cleanroom injection molding. On the mechanical side, insist on a formal first article inspection report against every drawing dimension before approving the first lot.

Pilot Build First, Then Full Rate

Run a pilot lot of 50 to 500 units on production tooling with production operators before committing to volume. The pilot has three jobs: generate the units for performance qualification, expose the assembly problems that only appear when someone builds the hundredth unit, and produce real cost and cycle-time data to replace the estimate in your business plan. The general mechanics are in the pilot production run.

Expect the pilot to generate a change list. Handle it through formal change control with an impact assessment against verification, validation, and the risk file, since a change that looks cosmetic can invalidate a completed test. Only after that list is closed and PQ lots pass do you release full-rate production.

Plan Transfer Before You Freeze the Design

Projects House takes medical devices from verified design into qualified production: manufacturing package, supplier qualification, validation protocols, pilot build, and the documentation trail an auditor expects. Send your device class and current development stage through our contact form.