How Stickers Are Inspected Before Shipment: A Factory Explains IQC, IPQC and OQC

Many first-time buyers ask: how do you make sure the stickers are right? The answer separates real factories from traders. A trader says we have strict quality control; a factory can tell you exactly which process checks what, and at what defect rate. This article breaks down the three gates.

1. IQC — Incoming Material Check: Roll and Adhesive First

The substrate of a foam sticker is foamed PVC roll, with adhesive laminated later. Skip this gate and a whole batch of 3D stickers can fail. Before each roll goes on the machine we check thickness uniformity, surface speckles, and whether the adhesive is evenly tacky.

2. IPQC — In-Process Check: Watched During HF Welding

HF welding is the key forming step for foam stickers. Operators sample every few dozen sheets: is the 3D height enough, is the emboss even, any bubbles or missing adhesive. Flaws caught here are pulled on the spot and never flow to the next stage.

3. OQC — Outgoing Check: Full or Sampling, Depends on Destination

At outgoing inspection, regular orders are sampled by AQL; orders for brands, gifts or e-commerce shelf placement get full inspection. Defect rate is bad-count over total-checked, normally under 3 per mille. Reworkable flaws (e.g. a few with weak adhesive) are pulled and re-glued; crushed or delaminated sheets are scrapped and redone.

So when a buyer asks how we guarantee no mistakes, the real answer is not a slogan but three traceable gates. Put your acceptable defect rate in the contract and the factory inspects to it — far easier than arguing afterward. For sampling and confirmed standards on custom artwork, use our customization flow.