Weighing is an accurate measurement of mass. To make a weighing measurement the weighing instrument needs to be correctly configured.
For example, if the process involves filling, the system must be designed to weigh a full supply hopper. It must also be able to handle large temperature changes. The latter affect load cell output, requiring the system to be recalibrated.
Types of Weighings
Almost every industry uses some type of weighing device to obtain precise quantifications of matter. These quantifications can be used to measure the quantity of ingredients in a recipe, determine shipping costs, or even ensure that products meet certain government regulations for safety and quality control.
The most common weighing devices are mechanical, electronic, and industrial weighing scales. Mechanical scales use springs to measure weight, while electronic and industrial weighing scales utilize advanced sensors for more accurate measurements.
Counting scales are another popular weighing device, which can measure the amount of identical parts or items. This is useful in food production, as it allows for efficient measurement of small batches. There are also specialized weighing devices for specific applications. These include analytical balances, which can measure very small quantities of chemical substances. In these cases, it is important to know how to correctly use these types of weighing instruments so that the results will be valid and reliable.
Calibration
Calibration is essential in many labs for accurate measurements and reliable results. It is particularly important in laboratories that work with hazardous materials, electric currents or volatile chemicals. Even small inaccuracies can cause safety hazards. This is why it is important to work with a calibration company that offers certified professionals and streamlined processes.
A calibration process is an exacting comparison of a measuring instrument with reference standards. These are typically transfer standards (certified reference material), primary standards held by a national metrology institute or derived from natural physical constants.
In addition to calibrating instruments, it is also important to properly document the calibration procedure. This includes details about the technician, measurement values and adjustments made. It is also helpful to capture information about the instrument itself, such as its make and model. This can be a valuable asset for future compliance audits. Calibration can also be facilitated by using software tools that allow for efficient task management and record-keeping.
Materials
In industries where quality and safety are paramount, such as pharmaceuticals or food production, the correct order of ingredients can make the difference between a safe medication and a harmful one. Proper weighing ensures that the right amount of each ingredient is used to maintain product consistency and ensure the highest quality for consumers.
A weighing system that can accurately measure multiple batches of a product reduces human error and produces more consistent results. This streamlined weighing process can also increase productivity and efficiency while reducing costs.
The first step to ensuring accurate weighing is to select a top-quality load cell. This is a piece of machined metal that bends under the force of the load, converting the mechanical force into an electrical signal that is measured by strain gauges bonded at points on the cell. It is important that the load cell and the surrounding work area be clean, as dust can affect the weighing result.
Errors
Errors in the weighing process can occur from a variety of reasons. Good laboratory techniques and equipment, along with accurate standards and balances, are essential for obtaining precise mass measurements.
Mechanical errors include vibration, air currents, lack of thermal equilibrium, and electrostatic charges. Choosing high quality components that have best-case specifications and ensuring proper installation and use will minimize these errors.
Electrical noise from RFI (radio-frequency interference) and EMI can throw weight readings by interfering with the load cell low-voltage signal sent to the controller. This can be caused by sources such as lightning, portable two-way radios, large power lines, static electricity, and solenoids.
Keeping the weighing platform clean can also reduce error. This includes assessing the settling time and ensuring that all components, including the weights, are dry and free of dust and corrosive contaminants. Handling tare weights and sample containers correctly can help avoid contamination, too. For example, avoiding touching the tare weights with bare hands eliminates finger grease that could add to their mass.