Pre-Production Sample Approval Process: What QC Inspectors Actually Check

Last month, I rejected a pre-production sample batch that had already passed the supplier's internal quality check. The stainless steel bottles looked perfect—flawless laser engraving, smooth powder coating, tight-fitting lids. But when I measured the vacuum insulation performance, the thermal retention fell 15% short of specification. The supplier was baffled because they'd never tested actual heat retention time; they only verified that the vacuum seal held pressure.

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