A Step-by-Step Guide to Quality Inspection Across the Supply Chain

Quality inspection is a structured quality control process designed to verify that products meet defined specifications, regulatory requirements, and customer expectations throughout the manufacturing and shipping lifecycle.

By applying inspection at key production stages, manufacturers, importers, and brand owners can reduce defect rates, prevent shipment disputes, and maintain consistent product quality.

This guide explains the four main types of quality inspection:

• Pre-Production Inspection (PPI)
• During Production Inspection (DPI or DUPRO)
• Pre-Shipment Inspection (PSI)
• Container Loading Inspection (CLI)

and how each supports an effective quality control strategy.

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1. Pre-Production Inspection (PPI)

Purpose

To verify raw materials, components, and production readiness before mass manufacturing begins.

When to Conduct

Before production starts or during the initial production phase.

What Inspectors Check

• Quality and specifications of raw materials and components
• Production equipment setup and workflow readiness
• Supplier capability and process consistency

Example

In textile manufacturing, inspectors may verify fabric color consistency, material composition, and measurement accuracy before cutting and sewing begin. Early detection of material issues helps prevent costly rework and production delays.

Key Benefits

• Identifies quality risks before production starts
• Confirms supplier preparedness
• Reduces waste caused by defective materials

Related Service: Pre-Production Inspection

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2. During Production Inspection (DPI)

Purpose

To monitor manufacturing quality while production is in progress and detect issues early.

When to Conduct

Typically when 20% to 60% of production is completed, depending on product complexity and risk level.

What Inspectors Check

• Sampling of semi-finished and finished products
• Assembly accuracy and workmanship quality
• Color consistency, labeling, and functionality

Example

For leather goods manufacturing, inspectors assess stitching uniformity, material quality, and finishing standards. Any deviations can be corrected before large volumes are produced.

Key Benefits

• Prevents widespread defects during mass production
• Ensures ongoing compliance with specifications
• Reduces rework and rejection costs

Related Service: During Production Inspection (DUPRO)

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3. Pre-Shipment Inspection (PSI)

Purpose

To verify finished products before shipment to ensure they meet quality, quantity, and packaging requirements.

When to Conduct

After production is fully completed and before shipment or container sealing.

What Inspectors Check

• Visual appearance and functional performance
• Product labeling and packaging compliance
• Quantity verification and carton condition

Example

Inspectors typically use the AQL (Acceptable Quality Limit) sampling method to evaluate defect levels against agreed quality thresholds.

Key Benefits

• Confirms shipment quality before dispatch
• Prevents defective products from reaching customers
• Reduces complaints, returns, and warranty claims

Related Service: Pre-Shipment Inspection

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4. Container Loading Inspection (CLI)

Purpose

To ensure goods are properly loaded, protected, and documented during the container loading process.

When to Conduct

During container loading, before sealing and transportation.

What Inspectors Check

• Quantity and product matching with packing lists
• Carton condition, stacking method, and palletization
• Container cleanliness, sealing, and load security

Example

Inspectors verify correct stacking patterns, adequate protective materials, and proper container sealing to minimize transit damage.

Key Benefits

• Reduces damage during transportation
• Confirms correct shipment quantities
• Ensures secure and compliant loading practices

Related Service: Container Loading Supervision

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Why Quality Inspection Matters

Quality inspection safeguards your brand reputation and ensures compliance with international standards. Conducting all four inspection stages helps identify issues early, maintain supplier accountability, and ensure consistent delivery performance.

According to industry benchmarks, companies that implement full-cycle inspection can reduce defect rates by 10–20% and improve supplier reliability significantly.

Explore ECQA’s full inspection solutions:

• Pre-Production Inspection
  
• During Production Inspection (DUPRO)
  
• Pre-Shipment Inspection
  
• Container Loading Supervision
  

Not sure which inspection stage fits your current production progress? Use our Inspection Selector Tool to get a recommended inspection type based on your manufacturing stage.