The quality of the weighing process depends on several factors, such as precise calibration and maintenance. This ensures that the equipment is working as it should, and that recorded measurements are accurate.
It’s also important to keep the work area clean and free of contaminants. This prevents errors that could occur due to dust or air currents.
Equipment
The equipment used in weighing processes includes scales, indicators, and load cells. They are used in a variety of applications from household and industrial scales to laboratory balances and precision and analytical balances. These instruments are critical to quality control in manufacturing, reducing product defects and ensuring accurate batch production.
Analytical and precision balances are used to weigh samples with high precision in chemical analysis. These instruments require a draft-free location on a stable bench and must be kept level for accurate measurements. They must be cleaned and handled with gloves or a weighing paper to avoid fingerprints that can affect the measurement.
Process weighing is used in the food, pharmaceutical, and chemical industries to automate a production line and ensure consistent results. This reduces raw material waste and increases productivity. It also eliminates human error and exposure to hazardous materials, improving quality and safety. Process weighing can include continuous monitoring of a silo or container, hopper blending, and dynamic weighing on conveyor belt systems.
Preparation
Precise weighing is critical to a wide range of analytical procedures, especially in industries such as pharmaceutical, food, plastics and chemical manufacturing, quality assurance labs and calibration laboratories. Manual weighing is often time-consuming, error-prone and susceptible to environmental fluctuations. The use of an automated weighing system allows the user to eliminate errors and save significant amounts of valuable time.
Prior to any weighing, the instrument should be inspected for proper operation and calibration. It must also be cleaned and dried to avoid the condensation of moisture or residue that can affect the weighing results.
In addition, it is a good idea to ensure that the laboratory environment is properly controlled for temperature consistency. This will help to reduce the influence of external factors that can compromise the weighing accuracy, such as air currents or heating/cooling vents. If the weighing system is located near these types of sources, a balance that utilizes a magnetic force restoration principle may experience electrostatic discharge in and around the pan, leading to erratic measurement readings.
Measurement
The measurement phase is the process of obtaining data to inform and improve future processes. This includes regularly testing and calibrating weighing equipment. This ensures that the accuracy of your measurements stays high throughout production. It also helps to reduce risks, such as product recalls or health concerns for consumers.
Powder materials must be weighed with extreme precision to ensure that they fulfill recipe specifications and quality requirements. Inaccurate weighing can result in poor-tasting or inconsistent food products.
Using a balance to measure the mass of a sample is one of the most common laboratory methods. A balance has a pair of pans that can be suspended from arms, called a beam or tron, and is used to measure the difference between an unknown mass placed in one of the pans and a standard mass added to the other. The differences in mass between the two are calculated as the position of a sliding mass along the balance’s scale.
Recording
The data your industrial scales collect – such as the weight of chlorine gas cylinders or a package’s shipping cost – must be recorded accurately. This process ensures that you have the correct measurement results in your inventory & helps reduce product waste & production time.
In manufacturing, precise weighing can help you maintain uniformity, even when your products have different attributes, such as color or taste. For example, a food factory could use quality control weighing systems to weigh each box of tablets before packaging to ensure that it contains the right number of chargers & instruction manuals.
Weighing is a vital component of pharmaceutical regulations, including USP & Ph. Eur. Both pharmacopeias define specific performance verification procedures that include calibration and routine testing activities. However, they have often not incorporated the application of underlying metrological concepts that would support this type of risk-based quality management system for weighing applications. New developments such as the inclusion of measurement uncertainty in the calibration of balances & the application of “as found” and “as left” calibrations in Ph. Eur should close this gap.