Pilot production

Pilot production (also a pilot run, pre-production run or pre-series production; European companies often say zero series) is the first limited batch of products made with production tooling, production material and the production process before full series production begins. Unlike prototypes, it does not validate the product design but whether the product can be made repeatedly at the required quality, rate and cost. Terminology varies between companies and industries: some distinguish a pre-series build, in which parts of the process are not yet production-intent, from a pilot run under fully production-representative conditions. In consumer electronics, the same stage is often called PVT (production validation test).

A pilot run validates the entire production chain: molds and tools, machine setup and process parameters, assembly fixtures and procedures, inspection gauges and measurement methods, packaging, logistics and the quality of purchased parts. The parts go to dimensional inspection with measurement reports, functional and durability testing and certification testing, and often also serve as first samples for the customer or for field trials.

The size of a pilot run depends on what needs to be validated, usually tens to hundreds of units, or more in high-volume production. The batch must be large enough to reveal process variation, not just one well-tuned part, so a preliminary process capability study (the Ppk index) is often evaluated for critical dimensions. In the automotive industry, this trial production is part of formal part and process approval, for example PPAP (Production Part Approval Process) according to AIAG or PPF according to VDA Volume 2.

Only a pilot run reveals the real shrinkage and warpage of molded parts, flash, differences between the cavities of a multi-cavity mold, actual assembly times and problems that never show up on hand-built prototypes. It is the last stage in which mistakes are still relatively cheap to fix.

Plan a pilot run whenever production starts on new tooling or a new line, when a new supplier takes over manufacturing or assembly, and whenever a defect in production would be costly (warranty claims, rework of thousands of units, a product recall). It typically follows the debugging and approval of samples from a new injection mold and precedes the first large shipment to the customer or the market launch.

Parts from pilot production are also well suited for certification testing, because the test lab then tests a product identical to the production version. For simple parts made with a proven process, such as machined components built to a revised drawing, a first article inspection is usually enough.

A common mistake is to build the pilot run with temporary parts, a mold that has not been fully debugged or hand-reworked pieces, and then declare the process validated. The results are not representative, and the problems only surface in series production. Insist on production tooling, production material and production conditions (takt time, operators, shifts), with inspection according to the control plan.

Agree with the supplier in advance on the quantity, on who pays for the pilot run and what happens to the parts (delivery to the customer, testing, scrapping), on the criteria for release to series production and on who signs off that release. Record the findings and carry design or process corrections into the documentation under a new revision, otherwise the problems you found will repeat in production.