A quality weighing process relies on more than just the right balance or scale. It also requires the proper procedure, equipment maintenance and a full audit trail.
Pharmaceutical and chemical industries often work with highly sensitive substances that require high accuracy. For this reason, weighing by difference is the preferred method for these applications.
Accuracy
The accuracy of your weighing process is critical to ensuring that your product meets the set standards needed for quality control and regulatory compliance. It’s important to understand what can affect the accuracy of your scale so you can make adjustments accordingly.
The first step to achieving accurate weighing results is to ensure that your weighing system has the right components and is in the right environment. One of the main components is your weighing load cell, which takes a mechanical force (such as you placing a weight on the scale) and converts it into an electrical signal. Moisture, temperature, and wire resistance can all cause interference in this signal.
It’s also important to make sure that your weighing scale is as stable as possible. This means ensuring that the floor or structure under it is strong enough to support the weight of your scale and other equipment without flexing. You can also reduce interference by using a draft shield on your Adam semi-micro or analytical balance and cleaning it regularly to eliminate any potential contaminants that can cause readings to drift.
Efficiency
Accurate weighing equipment can help your manufacturing business run lean and eliminate waste. This means less over-processing and fewer reworks to meet consumer demands.
Weighing raw materials, batch ingredients and final products is vital for meeting specifications, controlling costs and maintaining quality. Inaccurate weighing and inaccurate records can lead to out-of-specification results, which cost money and time to correct. Using best practices for your weighing system, such as calibration and preventative maintenance, can ensure peak performance and accuracy.
Efficient weighing processes can also increase your productivity by eliminating manual data entry and allowing you to make informed decisions that drive efficiency. Integrating your weighing instruments into your manufacturing software or ERP system allows data to trigger automation like opening valves or adjusting feed rates, which can optimize production and reduce waste. Choosing equipment designed to withstand your manufacturing environment and use conditions can further enhance efficiency. You can also improve efficiency by connecting weighing instrumentation to your plant controls, making it possible to share weights instantly to avoid rework or delays.
Safety
While weighing error is not entirely avoidable due to scale sensibility and calibration and technological limitations, it can be significantly reduced through weighing best practices. For example, hygroscopic samples that absorb moisture from the air can cause inaccurate measurements. It is also important to use clean hands and only touch the weights with a dry spatula to minimize any hand grease that could affect readings.
The weighing process is especially critical in hazardous industrial environments where a single spark might cause an explosion. In chemical, petrochemical, pharmaceutical and port areas that work with volatile chemicals and materials, safety standards like ATEX govern the operation of weighing equipment. A risk assessment, proper training and choosing technology designed for explosive environments are key to eliminating potential hazards.
For example, explosion-proof balances provide a safe working environment by allowing for electronic calibration to eliminate the need to bring test weights into the hazardous area. Integrated diagnostics allow system troubleshooting from the control room to further reduce the risk of bringing foreign material into an explosive atmosphere.
Reliability
Weighing is a common technique for measuring dry bulk material quantities and flowrates. It doesn’t require contact with the material, making it suitable for corrosive applications and operating in hazardous environments. It also eliminates measurement errors from the density of the material, allowing the user to focus on other factors that may influence batch quality.
Load cells are the basis of 99% of process weighing systems and must be selected with care from the outset to ensure accuracy, especially in hazardous areas. Load cells sense the load of a weigh vessel or platform and transmit an electrical signal via a junction box to a weight controller.
A weighing system that’s frequently used should be checked on a regular basis for issues such as vibrations, temperature and air currents that can affect readings. Keeping the balances in a stable environment and having them regularly calibrated with calibration weights will help to reduce these disturbances.