Sartorius AG (Germany) - Have you ever wondered how car airbags inflate during a collision? Interestingly, it involves a small —but very controlled — explosion at the precise moment of impact. The chemical reaction responsible for this uses a solid propellent that’s deposited inside the inflator module. To avoid dosing errors, integrated weighing cells  automatically verify this process during production.

In this post, we’ll talk about the different types of weigh cells, how they are integrated, and some of the interesting ways they are being used.

Accurate weighing is tied to product quality and safety:

Accurate and reproducible weighing is important in so many industries. From pharmaceuticals to battery production, using the correct amounts of components directly impacts the quality, and sometimes safety, of the final product.

Take a therapeutic drug as an example; deviating from the specified dose of the active ingredient can lead to under or overdosing, which may be dangerous for patients. Pharmaceutical manufacturers manage these risks by incorporating automated weigh checks along the production process.

OEM weigh cells are the backbone of industrial weighing:

An OEM weigh cell is a type of load cell that’s designed for use in original equipment manufacturer (OEM) applications. These devices measure force or weight and are very common in industrial weighing applications.

Load cells collect measurement in a few different ways, but electromagnetic force compensation load cells are by far the most accurate. These load cells use a magnetic field to counteract the weight of the object being weighed. The force required to balance the weight is then measured and converted into an electrical signal.

Integrated weigh cells provide continuous measurement:

Weigh cells can be integrated into a process in several ways, depending on the application. Sometimes, they are built into a piece of equipment, such as a filling machine or conveyor belt. In other cases, they are mounted on a platform and used as a standalone weighing system.

Integrated weigh cells bring a lot of efficiency, cost saving, safety, and reproducibility to industrial processes. In automated systems, weigh cells provide continuous measurement without any manual intervention. This is essential in chemical or pharmaceutical industries that work with exact amounts of active ingredients or potentially hazardous chemicals.

Modern weigh cells with data logging and connectivity also help support compliance requirements by providing accurate documentation.

Weigh cells are used in different steps of product manufacturing:

Companies use weigh cells in their production and testing process in different ways:

• Dosing: to add the correct amount of material to a product (e.g. when adding the active ingredient to a medication)
• Dispensing: to verify that the correct amount of a material is dispensed (e.g.  when injecting electrolyte, glue or gap filler during battery production )
• Counting: to count parts or other small items (e.g. when counting small components such as resistors and capacitors in electronics production)
• Statistical quality control (SQC): to monitor the weight of products and ensure that they meet specifications (e.g. when adding ingredients into the batch formulation of a pharmaceutical  )
• Check weighing: to check that a product is within a certain weight range (e.g. when dispensing tablets into a bottle with a filling machine)

Unique industrial applications of integrated weigh cells:

There are so many interesting examples of weigh cells in action. Here are a few that caught our attention:

Battery manufacturing quality control:

 We’ve written a lot about battery manufacturing lately, and weigh cells are a critical part of the quality control process. They are used throughout production to weigh raw materials (e.g. lithium), mix the slurry components, apply the correct amount of electrode coating, and check for correct assembly of the battery cell.

Czochralski crystal production:

Here’s a cool one: crystals! The Czochralski method is a way of growing single crystals of semiconductor materials, such as silicon. This process involves melting a small amount of the material in a crucible and then slowly pulling a seed crystal out of the melt while rotating it. As the crystal is pulled out, it solidifies and grows into a larger crystal. Load cells monitor the weight of the crucible and the growing crystal in real time, and the data is used to finetune growth conditions.

Sample preparation for metal analysis:

Our last example is about keeping toxic metals out of food, soil, and other organic matter. Analytical labs that do metal analysis need to prepare the sample before analysis by spectroscopy. The first step is sample digestion with sulfuric acid. Here, precise dispensing of sulfuric acid is critical—and integrated weigh cells make sure the job is done right.

High precision electromagnetic force compensation weigh cells:

Sartorius supplies a diverse selection of OEM weigh cells that easily integrate into almost any machinery or instrumentation. These cells are cut from a single block of aluminum and use electromagnetic force compensation technology for the best weighing accuracy.

Depending on the application, there are both custom solutions and standard options that cover a wide range, including micro weighing cells and explosion-proof weighing.