How Lot and In-Shift Inspections Contribute to a Closed-Loop Quality System

Consistently meeting customer’s requirements requires a commitment to excellence. A closed-loop quality system is crucial to consistently produce high-quality parts and demonstrates that commitment. The system continuously monitors and adjusts process parameters to maintain product specifications within acceptable limits. Lot and in-shift inspections play a significant role in this process by providing real-time feedback on part quality.

Data-Driven Feedback Loops

Feedback loops are used throughout the process at Noble Plastics to help engineers and technicians make data-driven decisions. From product evaluations until customer receipt of the products, we use the feedback to ensure we are on track or to drive changes to improve quality.

  • Project Evaluation – With our systems engineering approach, we capture all performance requirements, implement methods for achieving them, and prove we have met them. We start with discovery and design and then receive feedback in the testing and validation phases.
  • Product Onboarding – We take a scientific approach to product onboarding. Capabilities studies, done when we take over tooling, provide feedback that demonstrates if the tooling will consistently deliver quality parts. From scientific process development to statistical process control, we use feedback data we receive to make decisions that support our quality objectives or provide information on how we should improve.
  • Production – We seek feedback from our technicians, equipment, and the parts themselves throughout the production process. For example, robots at Noble Plastics can perform advanced vision inspection and even provide analog measurements if needed. Lot inspections and shift inspections play a critical role in the feedback loop.

Importance of Inspections in a Closed Loop Quality System

A closed-loop quality system that continuously monitors and adjusts process parameters as needed is vital for ensuring products meet customer specifications consistently. Lot and shift inspections play a significant role in this process by providing real-time feedback on part quality.

Lot inspections involve periodically sampling parts from the production line and testing them against critical quality attributes, such as dimensional accuracy or surface finish. The results of these tests are used to further refine the closed-loop control system.

The number of samples tested per lot is based on Acceptable Quality Limit (AQL) tables provided in ISO 2859-2. The table considers the number of pieces per lot and the number of defects the customer can tolerate to determine the number of products to be tested per lot. The lot will be rejected if the number of defects exceeds the maximum number allowed.

Similarly, in-shift inspections aim to catch defects before they become an issue. In-shift visual inspection could happen several times on a shift, depending on the product requirements.

Lot and in-shift inspections are critical feedback loops within the closed-loop quality system. By providing real-time data on part quality, these inspections allow more informed adjustments to process parameters to be made. This helps ensure that the system effectively responds to actual quality deviations rather than relying solely on theoretical models.

In addition to providing real-time feedback, lot inspections can also be used to identify trends in process performance and predict potential quality issues before they occur. For example, if a particular measurement is moving towards the edges of the acceptable tolerance, changes can be made before the parts become unacceptable. This proactive approach can help further reduce scrap and rework and ensure high-quality parts are consistently produced.

To reiterate, lot and in-shift inspections offer many benefits, including:

  • Improved product quality — Continuously monitoring products by lot and shift ensures that products meet or exceed customer specifications.
  • Reduced scrap — By preventing defects from occurring in the first place, scrap is reduced, saving time and money.
  • Increased production efficiency — Inspections can increase production efficiency by minimizing downtime and improving product quality when trends detect issues before they become defects.
  • Enhanced customer satisfaction — Consistent production of high-quality products increases customer satisfaction and loyalty.

Noble Plastics Unwavering Commitment to Quality

At Noble Plastics, quality is integrated into everything we do. From the moment a new customer onboards until the product is shipped out the door, our quality processes, including comprehensive inspections, ensure our customers’ quality expectations are met consistently.

Take the first step: contact us for a quote and experience for yourself the high-quality products of Noble Plastics.


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