When you use a new supplier, start new production operations, or shift your manufacturing overseas, there is often a great mismatch between your quality manufacturing expectations and your supplier. It becomes very difficult to enforce your quality leadership and Quality Management Systems on your suppliers, especially if you have hundreds of suppliers spread out in multiple locations and countries.
Managing your outsourced suppliers is about applying the right quality control tools at the right time. Here is a quick run-down on some of the tools you can use:
AQL (Acceptance Quality Limit)
A scientific method for determining the maximum number of defective units you are prepared to accept in each production batch. This tool should be used not just in the pre-shipment stage but also in the supplier’s materials selection processes. Suppliers should also have a systematized way of accepting and rejecting components and materials. The AQL consists of a table that sets out the inspection level for varying lot sizes and the maximum defect threshold.
Best applied to suppliers when you have a short-term or one-off supply relationship or you don’t really know the supplier. This inspection is usually used for simpler products that don’t have complex quality requirements.
This is the best problem prevention tool to reduce your unexpected procurement and financial losses. An audit is your opportunity to find out as much as you can about your prospective supplier before signing the purchase contract. In your audits, you should aim to get a comprehensive insight into your supplier’s financial, technical, production, quality control, personnel management, and customer handling capabilities.
Process and Line Inspections
To be used continuously if the supplier is new, or if the production volume is large, continuous, and long-term. Process or line inspections involve inspecting the product during the production process, rather than at the end. This allows defects and manufacturing problems to be detected early.
FMEA (Failure Mode Evaluation Analysis)
Best applied on new product production launched by new or existing suppliers to remove Critical to Quality and Critical to Usability problems. They can be applied at the system, subsystem, design, process, and service delivery levels. The main objective is to determine failure situations, assess their risk level, and evaluate how they can adversely affect performance.
PPAP (Production Part Approval Process)
A necessary tool when component conformity and compliance are critical in the production process. It is used mainly by the automotive and aerospace industries. PPAP defines the approval process for new or revised parts, or parts produced from new or significantly revised production methods. It essentially involves checking all the documentation, risk assessments, sample production parts, and production processes before manufacturing starts.
CAPA (Corrective Action Preventative Action)
Essential for preventing recurring quality problems or product defects. CAPA is an investigative process that looks into the root causes of a problem and the corrective actions that can be taken to prevent it from happening again.
APQP (Advanced Product Quality Planning)
The best method for ensuring quality and performance through thorough planning. Developed by the automotive industry and used mainly in advanced product manufacturing, the objective of the APQP is to produce a product quality plan that enables products that satisfy the customer to be developed. It looks into aspects such as design robustness, design testing, specification compliance, production process design, quality inspection standards, process capability, manufacturing techniques, and risk management.
SPC (Statistical Process Control)
For ensuring precise quality control in your suppliers’ production and developing continuous improvement practices. It involves using a number of statistical methods to monitor manufacturing processes for significant variability from specified parameters. Control charts are one of the most common tools used in this analysis.
The ASQ (American Society for Quality) also has a fantastic resource section where you can learn more about these quality control tools.