Statistical Process Control Transition Rules for Skip Lot Qualification
Transitioning to skip-lot sampling demands a proven Cpk of 1.33 across consecutive lots and contract rules that force instant reversion to full inspection upon any defect.
CTQ Features
Meaning
Critical characteristics of a product that directly impact its performance or compliance with regulatory requirements. Identifying ctq features is a mandatory step in the design for manufacturing process within Chinese export sectors. These attributes are the specific dimensions or material properties that a buyer will test during a quality audit.
If any of these parameters fail to meet the specification, the product is deemed unfit for its intended use.
Quality Priority
Focus on a limited set of variables ensures that inspection resources are directed toward the most influential aspects of the assembly. Manufacturers document these ctq features in the quality control plan to guide the production floor staff. This documentation becomes part of the technical file submitted to the China Quality Certification Centre for product approval.
Regulatory Compliance
Statutory requirements for safety and environmental protection often dictate which measurements are non-negotiable. Mandatory standards like the China Compulsory Certificate specify the ctq features that must be verified for electrical or automotive goods. Failure to maintain these specific standards can result in the revocation of the business license or heavy administrative fines.
Contractual Obligation
Supply agreements usually list these critical points to define the scope of the warranty. If the supplier changes a manufacturing step that alters the ctq features without prior approval, the buyer may terminate the contract. This protection ensures that the final assembly performs as designed across different production batches.