Performance Evaluation and Certification for Checkweighing Equipment

Performance evaluation and certification for checkweighing equipment is a critical process for ensuring product quality, legal compliance, and operational efficiency. Unlike static scales, checkweighers weigh products in motion, which introduces unique variables that must be carefully managed. A comprehensive evaluation and certification process ensures the system is not only accurate but also reliable under real-world production conditions.

Key Components of Performance Evaluation

1. Initial Assessment and Mechanical Inspection

Before any tests begin, a thorough physical inspection is necessary. This step ensures the checkweigher's fundamental components are in good working order and not causing any measurement errors.

• Visual Check: Inspect the conveyor belts, weigh platform, and frame for any signs of damage, wear, or debris. The weigh platform must be free-floating and not touching any surrounding parts.

• Component Integrity: Check for loose bolts, screws, or wiring. The load cell, which is the heart of the weighing system, must be secure and undamaged.

• Environmental Factors: The checkweigher's performance is sensitive to its environment. Factors like vibration from other machinery, temperature, and humidity can all affect accuracy. Technicians assess these conditions to ensure they are within the manufacturer's specifications.

2. Calibration and Verification

Calibration is the process of adjusting the checkweigher to ensure it measures weight correctly. Verification, on the other hand, is the act of confirming that the system is performing accurately and consistently.

• Static Calibration: This is a preliminary step where the checkweigher is calibrated with certified test weights while the conveyor is stopped. It establishes a baseline of accuracy.

• Dynamic Calibration: This is the most crucial part for a checkweigher. A known, stable product (or a test weight) is passed over the moving conveyor multiple times. This test confirms the system's ability to accurately weigh products in motion.

• Repeatability Test: To check consistency, a single product of known weight is run through the checkweigher multiple times (e.g., 10-20 times). The recorded weights should fall within a very tight tolerance, typically within a few standard deviations, to prove the machine's repeatability.

• Corner Load Test: For static calibration, a weight is placed at different corners of the weigh platform to ensure the system measures accurately regardless of where the product is positioned. This verifies the performance of all load cells.

Specifications: