Mastering The Art Of During Production Inspection (dupro) For Unstoppable Manufacturing

By Author: TIC
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You've secured the perfect factory, verified the raw materials with a solid Pre-Production Inspection (PPI), and mass production has finally begun. Everything is running smoothly, right?
Not necessarily.

The production phase is the longest and arguably the most volatile stage of the manufacturing cycle. This is where subtle problems—like machine drift, inconsistent worker training, material substitutions, or fatigue—can creep in and turn a perfect start into a disastrous finish.

Relying solely on a final check (Pre-Shipment Inspection, or PSI) is a gamble. By the time a PSI fails, the entire order is finished, defects are locked in, and your only options are costly rework or devastating delays.

This is why the During Production Inspection (DUPRO), performed by experts like The Inspection Company (TIC), is an absolute best practice for sophisticated sourcing operations. The DUPRO is the proactive quality check that ensures your standards are maintained, not just at the start, but throughout the manufacturing process.

What is a During Production Inspection (DUPRO)?

A DUPRO, sometimes ...
... called an In-Line Inspection, typically occurs when 10% to 20% of your order is completed, or when a high-risk process is underway.

It is a comprehensive physical inspection that involves:

✅ Checking the partially completed goods to catch recurring defects early.

✅ Reviewing the production line processes to ensure the factory is following approved methods.

✅ Verifying material and component usage against the approved Golden Sample and PPI report.

✅ Confirming packaging and labeling accuracy on the finished 10-20% of the goods.

The DUPRO is your mid-course correction, ensuring the quality standards established during the PPI are actively and consistently maintained.

10 Best Practices for Executing a High-Impact DUPRO

To ensure your DUPRO delivers maximum value, it must be performed strategically and comprehensively. Here are the 10 best practices deployed by The Inspection Company that elevate the DUPRO from a simple check to a powerful management tool:

1. Timing the Inspection for Maximum Impact

Best Practice: The DUPRO should ideally be scheduled when 10% to 20% of the total order quantity has been completed and packaged.

Why It Works: This window is critical. It allows enough time for any initial production mistakes or ambiguities to surface and provides the factory with enough time—and enough un-produced quantity remaining—to implement corrective actions without stopping the line or causing major delays. Scheduling too early yields little data; scheduling too late leaves too little time for rework.

2. Focusing on High-Risk and Critical-to-Quality (CTQ) Points

Best Practice: The inspector's focus must shift from a general check to a laser focus on critical quality points and any known high-risk processes unique to the product.

Why It Works: Based on the PPI findings, or the product's history, certain elements are known to be riskier (e.g., complex electronics assembly, heat treatment steps, printing registration, or intricate stitching). The TIC inspector prioritizes these CTQ areas, spending more time verifying that high-risk processes are consistently under control, ensuring potential failures are preempted.

3. Verification Against the Approved Golden Sample and PPI Report

Best Practice: The DUPRO must be a direct comparison against the approved Golden Sample (established during the PPI) and the specific checkpoints agreed upon in the initial inspection report.

Why It Works: This prevents the factory from changing specs mid-run. The DUPRO verifies that the production line is sticking to the approved materials, colors, dimensions, and functional requirements. If the PPI report highlighted a specific packaging issue, the DUPRO verifies the corrective action has been implemented successfully.

4. Comprehensive On-Site Functional and Performance Testing

Best Practice: The DUPRO must include rigorous on-site functional and performance testing to ensure products perform as expected.

Why It Works: While the final PSI tests the packaged product, the DUPRO tests the product in action. This includes stress tests, load-bearing checks, power-up tests for electronics, zipper cycle tests, or light fastness checks. Catching a functional failure at the 30% mark prevents 70% of the production from being unusable.

5. Applying the AQL Standard to Statistical Sampling

Best Practice: Defects are assessed using the internationally recognized Acceptable Quality Limit (AQL) standards (e.g., ANSI/ASQ Z1.4).

Why It Works: A DUPRO is not an exhaustive check of every single unit. Using AQL ensures a statistically valid and efficient inspection. The inspector randomly selects a sample size (based on Lot Size and Inspection Level) from the completed 10-20% and classifies defects as Critical, Major, or Minor. This scientific approach provides an objective snapshot of the entire batch's quality level.

6. Thorough Process Audit and Environment Check

Best Practice: The inspector evaluates the manufacturing processes and the factory environment in addition to the product itself.

Why It Works: Process integrity equals product integrity. The inspector verifies:

✅ Work Instructions: Are correct work instructions displayed and followed by all workers?

✅ Material Flow: Is there proper segregation of good materials, defective parts, and finished goods?

✅ Housekeeping: Is the area clean, which is crucial for sensitive items (like electronics or food-contact materials)? Poor housekeeping often leads to contamination and damage.

7. Immediate Communication of Corrective and Preventive Actions (CAPA)

Best Practice: Any non-compliance found during the DUPRO must trigger an immediate demand for Corrective and Preventive Actions (CAPA).

Why It Works: The advantage of the DUPRO is immediacy. The TIC inspector immediately communicates the findings to the factory management and works with them to create an actionable plan to fix the existing defects (Corrective) and prevent them from recurring on the rest of the order (Preventive). This fast-tracked action saves days, if not weeks.

8. Verification of Packaging and Labelling Accuracy

Best Practice: The DUPRO checks that the correct inner and outer packaging materials, markings, and labels are being applied to the completed units.

Why It Works: Packaging mistakes are often final and costly. Incorrect barcodes, missing compliance marks (like CE or FCC), or wrong assembly instructions will cause customs issues or retail chargebacks. Checking this at the DUPRO stage ensures the factory gets the packaging right for the remaining 60-80% of the order.

9. Providing Detailed, Real-Time Reporting with Visual Evidence

Best Practice: The report must be delivered quickly (ideally within 24 hours) with extensive photographic and video evidence.

Why It Works: You need actionable intelligence instantly. A TIC DUPRO report provides a clear Pass/Fail/Hold status, a detailed breakdown of defect rates against the AQL, and precise photos of the defects and the production process. This visual evidence enables you to make swift decisions on the remaining production run from anywhere in the world.

10. Follow-Up and Accountability for Rework

Best Practice: The inspection company must track the implementation of the required CAPA and confirm any necessary rework is done before the final PSI.

Why It Works: A DUPRO's effectiveness is measured by the follow-through. If the factory promised to fix a mold error, the inspector ensures that the mold has been fixed, and the reworked products meet the standard. This final layer of accountability protects your entire investment.

Conclusion

The During Production Inspection is the quality checkpoint that empowers you to maintain control when your supply chain is moving at full speed. It transforms your approach from reactive damage control to proactive quality assurance.

By integrating the TIC DUPRO Best Practices into your sourcing strategy, you ensure:

✅ Consistency: Every unit adheres to the Golden Sample.

✅ Speed: You avoid costly rework and subsequent shipping delays.

✅ Confidence: You know the final PSI is highly likely to pass, leading to immediate shipment authorization.

Don't let your quality standards slip once production starts. Keep your project on track, on time, and on quality.

Ready to achieve unstoppable manufacturing quality? Contact The Inspection Company today to schedule your next During Production Inspection and secure the integrity of your entire production run.