The weighing process is an integral part of many production processes. It is used to determine a material’s true value and ensure that a product meets its quality standards.
Despite the importance of the weighing process, there are many factors that can affect accuracy and reliability. This article discusses several of these factors and how you can reduce errors in your weighing process.
Accuracy
The accuracy of a weighing process refers to how close the results are to their true value. It can also be defined as the level of precision a measurement system shows.
This is important because it allows you to accurately predict the weight of a product or material. Accuracy is affected by a number of factors, including environmental forces and the way you load your weighing vessel.
When a weighing system is not properly installed, it can have an effect on accuracy. For example, if the system is located outdoors or near a windmill, it could be exposed to air movement that affects the load cells and creates inaccuracies.
To avoid this, ensure that all load cells in the weighing vessel support all of the weight to be measured. This will prevent side loads from affecting the load cells, which can cause system binding. You can also add cross bracing to the legs of your weighing vessel to strengthen its structure and preserve weighing accuracy.
Reliability
The reliability of a weighing process refers to the accuracy and consistency of results. This means that the measurements of a sample will be within acceptable limits and satisfy quality requirements.
Accurate weighing is essential in manufacturing processes to ensure product quality and fulfillment of regulatory requirements. This requires accurate and fast transfer of measurement data to controller and I/O devices for monitoring and real-time adjustment.
Another important part of the weighing process is checkweighing, which prevents wrong materials from being used and enables real-time corrections of deviations. In addition, weighing solutions provide material ID points that can help manufacturers fulfill regulatory requirements and meet safety and quality standards.
Reliability can also be improved by limiting human subjectivity and asking more precise questions. For example, if you ask people how long they expect to be out of work after surgery, the results may not be as reliable as if you asked them to rate their recovery time in a numerical scale or as a percentage.
Safety
A reliable weighing process is essential in ensuring that all processes are performed to the highest standards, reducing production costs and improving efficiency. It is also important to keep the weighing equipment and its environment safe.
To do this, a risk analysis must be conducted to determine the probability and impact of a wrong measurement on the product being weighed. This can help establish a regular routine of testing and inspection.
In addition to a good weighing process, the scales themselves can be tested to ensure that they are functioning properly and meet accuracy requirements. Scales that fail to perform can result in out-of-spec products that may harm people or cause damage to the products being weighed.
Keeping the weighing environment clean and safe reduces the chance of contamination and allows the scales to operate at their maximum potential. In addition, proper cleaning methods prevent rust, pitting and other environmental damages from affecting the weighing results.
Calibration
Calibration is the comparison of a measuring instrument or process with a known value (a standard). It establishes an understanding of how a device behaves and explains its error.
To calibrate a weighing scale, a certified technician uses a reference weight or known weights and adjusts the scale’s response. The resulting calibration should result in output results that are within specified tolerances and have negligible error.
A traceable calibration of a weighing instrument is the only way to know whether it is measuring accurately. This is done by comparing the instrument with a primary standard and documenting the comparison.
The primary standard may be a national or international measurement standard, or a certified reference material. A calibration laboratory will transfer the traceability from one standard to another, through an unbroken chain of comparisons in which all uncertainties are indicated.
If you are going to have a calibration done, make sure it is performed by a highly experienced and certified team. Look for a CWT (Certified Weighing Technician) who has years of experience in scale calibration, formal NIST H-44 training and re-certification every five years.