From Manual Sampling to 100% Inspection

The plant, a mid-sized oral solid dosage (OSD) manufacturer supplying domestic retail and institutional markets across India, operates six packaging lines running tablet strips, blister packs, and secondary cartons. With more than 400 employees and production volumes reaching tens of thousands of units per shift, the facility had grown significantly over the years.

Yet, despite its scale, weight verification on secondary cartons was still being performed exactly as it had been when the plant first opened. Production supervisors manually sampled from each batch, weighed them on benchtop scales, recorded the values in paper logbooks, and signed off the results. Typically, only five to ten cartons were checked from batches of several thousand.

For many years, this approach had been considered sufficient under standard operating procedures. That changed during a routine regulatory inspection when inspectors requested historical weight distribution data.

The inspection highlighted a significant gap between growing regulatory expectations and the plant’s existing quality assurance process.

Following a comprehensive site audit and line-speed analysis, Kevision recommended installing Checkweigher 350 on the plant’s highest-volume production lines, with a phased rollout planned for the remaining lines.

Delivering high-speed accuracy with HBK’s FIT7A digital load cell technology

To meet the plant’s rigorous accuracy and throughput requirements, Kevision selected HBK’s FIT7A digital load cell as the foundation of the Checkweigher 350 platform.

The FIT7A enables the system to weigh every carton in real time at speeds of up to 350 products per minute while maintaining an accuracy of ±0.5 g. Unlike traditional analogue strain-gauge systems that can be affected by thermal drift and signal noise, the FIT7A combines integrated electronics directly adjacent to the sensor with active temperature compensation. This delivers highly stable, repeatable performance throughout full production shifts without requiring frequent, time-consuming recalibration.

Its exceptionally rigid mechanical design delivers fast signal response and short filter times, making it possible to perform precise measurements at high conveyor speeds without compromising reliability. As each carton passes through the weighing station, its weight is verified within milliseconds. Products that fall outside predefined upper or lower weight limits are automatically rejected, ensuring that only compliant cartons proceed further down the line.

Beyond accurate weighing, the system provides complete production visibility and traceability. Electronic batch reports are generated automatically, full 21 CFR Part 11-compliant audit trails are maintained, and seamless communication with upstream and downstream equipment is achieved via Ethernet/IP integration. Together, these capabilities eliminate the need for manual sampling while giving operators and quality teams access to comprehensive compliance and performance data for every batch produced.

The Checkweigher 350 uses a three-belt conveyor design comprising infeed, weighing, and outfeed sections.

The infeed conveyor spaces cartons so that only one product occupies the weighing platform at any one time. As each carton passes through the weighing zone, a precise weight measurement is captured within milliseconds.

Any carton that falls outside preset tolerance limits is automatically diverted into a lockable stainless-steel rejection bin. An optional rejection verification sensor confirms successful removal, providing additional assurance that non-compliant products cannot proceed downstream.

A transparent acrylic wind tunnel protects the weighing section from airflow disturbances generated by HVAC systems, helping maintain weighing stability even in demanding production environments.

The Checkweigher 350 was commissioned and validated within five working days, including IQ/OQ execution and the first batch production trial. From the first commercial batch, the results were immediate and unambiguous.
 

• Zero non-compliant batches dispatched since go-live • False rejection rate below 0.05%
• 100% of cartons weighed inline
• One-click automated PDF batch reporting 

Beyond the headline numbers, the quality team reported a fundamental shift in how weight compliance is managed. Statistical process control metrics such as mean weight, standard deviation and Cpk are now available on demand through the HMI or can be exported as PDF reports at batch close. The plant’s next scheduled regulatory inspection resulted in zero weight-related observations – the first clean inspection in this category in four years.