Good laboratory practices and quality weighing equipment are critical for accurate mass measurements. Errors can occur due to a number of factors.
Whether you’re a chef perfecting a recipe or a healthcare professional ensuring patient safety, precise weighing is key. This article will cover the steps necessary to accurately conduct a weighing process.
Weight Measurement
Weighing is the process of measuring an object or substance’s weight, which is a measure of its force due to gravity. The term “weight” is also used to describe an individual’s body mass, which is the total amount of matter in their body.
A spring scale measures an object’s weight by observing how far the object pushes a spring. This is different from a balance scale, which compares the force exerted on an object to a standard reference weight.
A weighing system’s accuracy depends on the quality of its components. It’s essential that the load cell—also known as a sensor or transducer—can support the entire load to be measured. The load cells send a signal proportional to the load through a junction box and to a weight controller. The weight controller converts the signal into a readout on a display or digital panel. The junction box and weight controller must be located away from the load to avoid interference from vibrations, pulsations and other forces.
Calibration
Scales that are used for more complex tasks or in higher sensitivity applications may require specialist calibration. This includes pharmaceutical, aerospace, and manufacturing scales as well as hanging scales, industrial and truck scales and other larger scale equipment. LotusWorks offers a tailored balance calibration service using mobile teams and an ISO 17025 2017 accredited laboratory.
Calibration is the process of testing a weighing instrument to establish a relationship between the measurement technique and known values. This teaches the instrument to provide more accurate results when samples of unknown value are tested.
It is essential to select the correct calibration weights and perform a few pre-tests before starting the full calibration process. Ensure the calibration environment is stable and free from drafts, vibrations or temperature fluctuations. Lastly, it is important to tare the weighing instrument with an empty weighing pan to set the display to zero. Depending on the calibration procedure, the scale will then be tested with increasing and decreasing test loads.
Traceability
Traceability relates to the fact that a measurement can be traced back to a defined standard. This is a key element in the overall quality of your weighing process.
The National Institute of Standards and Technology (NIST) is the keeper of the ultimate definition of a pound, as well as other measurement units like inches, seconds and volts. They ensure that every scale has an unbroken chain of calibrations to the underlying standard, giving you confidence in your results.
When weighed materials are processed, they can be subject to many contaminants that may be introduced during handling and transfer. Adding a small amount of water to your weighing container helps dissolve and loosen any remaining solids or other liquids that are trapped in the container, making for a cleaner process. In addition, this practice promotes lean manufacturing and continuous improvement. It can also help prevent costly product recalls.
Automation
Weighing automation is a crucial step to achieving efficient, reliable, and cost-effective production. However, this does not negate the need for human oversight. Rather, it allows you to shift your workforce to duties that require more hands-on attention.
Precise weighing ensures the order of ingredients in a mixture, maintaining product consistency and quality. This is especially important for food and pharmaceutical manufacturing where errors could be costly.
Streamlined inventory management helps reduce unnecessary expenses by providing instant access to information about products and their origins, as well as previous weighment records. This enables you to track inventory and detect any potential problems, such as under- or over-loading trucks.
Smart weighing systems are integrated into industrial automation networks using a protocol known as Industrial Ethernet (IE). This makes it easy to transfer time-critical and deterministic process control data, as well as business intelligence data between OT and IT systems. This enables you to optimize your overall production and make faster decisions about your business operations.