An automation of a customer’s manual weighing process can be highly beneficial. In this case study, Grand Rapids Metrology explains how it automated a manual process in a manufacturing environment. A global manufacturer of analytical instruments faced a manual weighing process that was time consuming and inaccurate. Additionally, the scale used by this company was outdated, and therefore, not suited to the customer’s specific application. A new automated system eliminated this challenge.
When a weighing process is used to measure the concentration of a compound, it’s important to remember that different substances have different levels of accuracy. In addition, materials with stratified layers will have different dielectric constants. This means that materials with poor reflectivity and conductive materials will not affect the weight of the compound. Furthermore, weighing processes do not produce contamination, so a process that involves the use of caustic materials can be damaging to a weighing system.
Manual weighing processes are still indispensable in many facilities. The human factor in manual weighing adds flexibility and allows for low-cost adaptation to changing market conditions. However, manual weighing does have gaps in its efficiency. The ICS series of scales from Mettler Toledo minimize these variables and preserve the flexibility of manual processes. For example, weighing a batch of raw materials can be done quickly and accurately without the need for manual zeroing. Furthermore, it eliminates tare weights and keystrokes.
Another method of weighing a substance is direct weighing. This method involves placing the substance to be weighed on a clean weighing paper and then weighing it again. The difference between the first and second readings is then used to determine the mass of the substance. It is important to use a clean spatula when placing the sample onto the balance. The use of butter paper is another option, but it introduces errors. While butter paper weighing is effective in some applications, it is not recommended in other situations.
In the absence of a tare machine, the most convenient way to weigh chemicals is to use a taring balance. This type of balance automatically weighs by difference, and the mass of the substance being weighed is displayed on the weighing pan. It is a convenient and accurate way of weighing chemicals. The only drawback to this method is that it introduces another source of inaccuracy: the weight of the container. Furthermore, this method cancels out the initial reading errors and is more accurate than weighing by difference.
The accuracy of a weighing system depends on several factors, including its components. A typical weighing system includes a load cell, a junction box, and a weight controller. The load is transmitted to the load cells, which in turn emit an electrical signal proportional to the weight. The signals from the load cells are then combined and converted to a weight reading. This method requires high accuracy, so the weight of a material is crucial to the process.
Despite the importance of accurate sample weighing, the weighing process can be complex. It may not be possible to manage all sample cases, and weighing one sample at a time can become a laborious and time-consuming process. Using LIMS software for sample management will allow a streamlined sample weighing process, automated guidance for operators, and an audit trail of operations. It will also ensure that sample cases are accurate and up-to-date.
In addition to being accurate, load cells have a number of other properties that can impact their performance. For example, improperly applied loads can cause strain gauges within a load cell to change their signals proportionally to the amount of twisting the load applies. By understanding these characteristics, load cell accuracy will improve. With these characteristics in mind, the next step is a comprehensive analysis of load cells. And, as always, make sure you use the correct type of load cell and instrumentation to ensure the accuracy of your weighing process.
A traditional scale consists of two plates or bowls suspended at equal distances from a fulcrum. One plate holds an unknown mass, while the other is weighed and added. When the masses on both plates are equal, the weighing process has reached static equilibrium. A perfect scale would rest in the neutral position. Spring scales, on the other hand, use a spring of known stiffness. Any mass suspended over the spring will stretch the spring a certain distance, which increases with the mass. This process is known as Hooke’s law.
In the bulk weighing industry, a bulk weighing system is used to measure loose grain. This system involves a weigh hopper and load cells, which generate an electrical signal proportional to the weight of the grain. Then, a scale indicator records the tared output from each load cell and displays the net weight of the grain. The scale control computer is responsible for operating the gates, allowing the product to flow into the weigh hopper sequentially or in a continuous manner.