Pilot batch: what to check before you say yes to mass production

Between approved samples and mass production there is a run of a few hundred units called the pilot batch. It is made on the production line, by the production staff, with the production tooling. It is the first time the product is made the way it will be made for years. It is also the last time a change is cheap.

Here is what we check before we sign off a pilot batch. Our Shanghai team does this on site; the list is the same anywhere.

Parts

• Dimensions against the drawing. Every toleranced dimension on a sample of parts, not one golden unit. We want to see the spread, not the best one.
• Cosmetics against the approved sample. Colour, gloss, texture and sink marks compared under the same light as the signed reference. Keep the signed reference at the factory in a box with a date on it.
• Material certificates. The resin, the alloy, the coating. A pilot batch is the moment to confirm that what was quoted is what is being used.

Assembly

• Time per unit. The pilot run gives the first real assembly time. If it is far above the estimate, the unit price is about to change, and better to know now.
• Operator notes. The people on the line will tell you which step is awkward. Those steps become the scrap and warranty problems later. Fix the design or the jig before the main run.
• Fastener and adhesive torque and cure. Written down, with the tool settings.

Function

• Every unit powered on and exercised, not a sample, if the product has electronics. Pilot quantities are small enough.
• Mechanisms cycled. A fold, a hinge, a click: a defined number of cycles on a defined number of units.
• The abuse the product will actually get. For a bar object, a dishwasher. For a medical instrument, the autoclave. For a sensor, the vibration the datasheet promises.

Packaging and shipping

• Drop test the packed product. Then open it and check the cosmetics again.
• Labels, manuals, inserts. Correct language, correct version, correct barcode. These are the cheapest things to get wrong and the most embarrassing.
• Carton and pallet dimensions against the shipping quote.

Documents

• A signed inspection report with photos, measurements and a list of deviations, each marked accept, rework or reject.
• An updated bill of materials with every substitution the factory made during the pilot. There are always some.
• A list of changes for mass production, agreed with the factory, with a date for each.

When to say no

If the pilot batch has a defect that would be a warranty return, the main run waits. Delaying a container by three weeks costs less than the first thousand returns. Every client agrees with this in principle. The pilot batch is where it gets tested in practice, usually against a launch date.

Our advice: put the pilot batch in the schedule from the start, with time after it for one round of changes. A pilot batch that is only a formality is not a pilot batch.