Quality control in manufacturing: keeping an overseas order to spec

Quality control and quality assurance

ASQ (the American Society for Quality) separates the two terms: while quality assurance concerns how a product is made, quality control is more the inspection aspect of quality management^[1].

For a brand that buys from factories, the split is practical. The factory's quality assurance is its own system: incoming material checks, trained operators, calibrated equipment, and its own quality control on the line. You judge that system before you order, with a factory audit. Quality control is what you do on each order: checking that the goods made for you match what you agreed. A good system makes good orders more likely, but it does not replace checking the order.

Write the standard before anyone makes anything

Nobody can control quality against a standard that only exists in your head. Before production, the factory should hold:

• a spec sheet or tech pack with every dimension, material and color, and a tolerance for each measurement;
• an approved pre-production sample, signed and kept by both sides as the reference;
• a defect list sorted into critical, major and minor, with photos where you can;
• the acceptance level for each defect class, as an AQL, and the inspection level;
• packing, labeling and carton marking instructions;
• the lab tests the goods must pass, and who pays for them.

Some tolerances are set by law, not by you. For a textile product made of more than one fiber, the label is not misbranded as to fiber percentages if each fiber's actual share differs from the label figure by no more than 3 percent of the total fiber weight of the product^[2]. But where representations are made to the effect that a textile fiber product is composed wholly of one fiber^[2], that tolerance does not apply, except for permissive ornamentation when the label says the product is one fiber exclusive of ornamentation. A shirt labeled as all cotton has to be all cotton, so a fiber content test belongs in the plan for any clothing order.

Checks through the order

Book the first-units check and the finished-goods inspection when you place the order, not when the factory says the goods are ready. An inspection that happens after the balance is paid has little leverage behind it.

The legal floor: when testing is not optional

Under the Consumer Product Safety Act, a manufacturer means any person who manufactures or imports a consumer product^[3]. If you import the goods, the manufacturer's testing and reporting duties are yours, whoever ran the production line. For a product made outside the US that needs a certificate, the importer is the finished product certifier that must issue a finished product certificate^[4], unless a specific rule, ban, standard or regulation enforced by the Consumer Product Safety Commission provides otherwise.

For children's products, meaning a consumer product designed or intended primarily for children 12 years of age or younger^[3], the rules set a schedule. By default, periodic testing, conducted by a third party conformity assessment body^[5], is required at least once a year^[5]. Other routes stretch the interval, such as testing at least once every two years^[5] under a production testing plan, which may use control charts, statistical process control programs, or failure modes and effects analyses (FMEAs)^[5], or at least once every three years^[5] when the continuing tests use a laboratory accredited to the international standard for testing laboratories that the rule names. And when a children's product undergoes a material change in product design or manufacturing process, including the sourcing of component parts^[6] that could affect compliance, the manufacturer must submit a sufficient number of samples of the materially changed children's product for testing by a third party conformity assessment body and issue a new Children's Product Certificate^[6]. A factory that quietly switches its zipper or paint supplier has made exactly that kind of change, so write "no substitution of materials or components without written approval" into every purchase order for toys and children's goods.

For any consumer product, a firm that obtains information which reasonably supports the conclusion that its product fails to comply with a safety rule or voluntary safety standard, contains a defect which could create a substantial risk of injury, or creates an unreasonable risk of serious injury or death should report to the Consumer Product Safety Commission within 24 hours^[7]. Keep inspection and test records where you can find them quickly.

When a lot fails

A failed inspection is the start of a negotiation, and the order terms decide how strong your position is.

1. Hold the balance payment. Tie the balance to a passed final inspection in the purchase order.
2. Agree the fix. Sorting, rework or remaking, depending on the defect, with a date for the goods to be ready again.
3. Re-inspect, at the factory's cost. Put that cost rule in the order before production starts.
4. Find the cause. Ask for a short written corrective action: what went wrong, and what changes on the line.
5. Record it. Keep the reports by supplier and defect type, so a pattern shows up before your next order.

What quality control costs on an order

Quality control on an order of 4,000 units

Line	Amount
Order value, 4,000 units at $6.20	$24,800
Material and component test reports	$180
First-units check at the factory	$320
Final inspection before shipment	$320
Lab testing for the product	$450
Quality control cost	$1,270
Quality control cost per unit	$0.32
For comparison: 120 defective units reaching customers at $14 each in refunds, return shipping and lost stock	$1,680

Illustrative figures, not a quote. Real prices depend on the spec, quantity and factory.

A sampling plan lowers the chance that a lot with that many defects ships, but it does not remove it, which is why the stages before the final inspection matter. The comparison line also leaves out the reviews and repeat customers a bad batch costs, which can be the larger bill. Checks cost the same whether a lot passes or fails, so treat them as part of the unit price when you compare quotes.

Getting quotes

Send us your spec, your tolerances and the quality terms you want written into the order, and we introduce you to manufacturers that fit, overseas first, each one named; if none fits, we tell you. It is free for brands, and we are not a party to the sale: the manufacturers quote you directly against that spec, and the order, with the quality terms in it, is between you and the one you choose. Ask each quote to state its shipping terms and the inspection and retest terms it accepts.