With the help of recently purchased software for magnetic calculations, R&D engineers Martijn Leskens at Goudsmit Magnetics use finite element or FEM methods to show product behavior in magnetic systems and quantify magnetic performance. Martijn (Martijn): 'We can effectively optimize the performance of this product through magnetic force calculations. This enables us to accurately predict magnet behavior based on magnetic field depth (known as "flux density") and the force acting on another ferromagnetic object.'

Magnet separation efficiency

We can also estimate the separation efficiency for removing steel and stainless steel particles from powdered, gaseous, or liquid product streams, as seen in the food industry. For this, we use the Comsol calculation program. It provides a very accurate estimation of real-world conditions.'

Magnetic field

The following video shows the behavior of steel and stainless steel particles in a product (in this case water, but it could also be liquid food) within a magnetic filter, and how they flow through the magnetic field and are captured. This provides insight into the effectiveness of the magnetic field, its impact on magnetic separation efficiency, and the particle sizes and flow distributions to be captured. Metal contamination must pass through the magnetic field. We demonstrate this through calculations. By comparing several videos, we can also demonstrate differences in separation efficiency due to particle size.'

Video 1 - FEM calculation of electromagnetic filter (for steel particles)

Video 2 - FEM calculation of electromagnetic filter (for stainless steel particles)

Flux density

Why is proving this separation efficiency so important? We consulted our colleague Guy Mutsaerts, an expert in magnets for the food industry. Guy: We know that to capture iron or ferrous materials, at least 155 Gauss is required, while for 304 grade stainless steel, at least 1100 Gauss is needed. Through this simulation, we can see if this is theoretically achievable. We are currently testing this theory in practice to provide a guaranteed separation assurance. These tests take a lot of time. We have set a minimum requirement of at least 300 Gauss for capturing ferrous particles. Goudsmit is the only magnet supplier in the world that uses this program for magnet calculations and can provide this guarantee.

Magnet measurement

Guy continues: 'When measuring magnetic field strength, we not only recommend the correct flux density, but cleaning and implementation are also important criteria. For example, situations where there are no stainless steel tubes around the magnets (open pole systems); they will rust, and bacteria will grow between the magnets. The distance between the rods also affects performance. These are often placed further apart to achieve greater capacity.'

This leads to gaps in the magnetic field, preventing the capture of all iron particles. To overcome this defect, I advocate including minimum flux density in the HACCP specifications for the food industry. After all, the minimum flux density value determines whether iron particles can be completely captured.'  

Finite Element Modeling (FEM)

Finite Element Modeling (FEM) is a proven method for system analysis and optimization that can significantly reduce product development time and costs. Using this modeling tool, the area of interest is divided into small elements, through which basic physical equations can be solved for each small element.

For companies working with magnetic materials like Goudsmit Magnetic Systems, it is an important tool because it can relatively accurately predict the performance of their electromagnetic systems. This article provides a more detailed overview of the FEM method currently used at Goudsmit and discusses the various applications of this method encountered at Goudsmit. This helps provide a concept of how FEM is used for the analysis and optimization of magnetic systems, as well as the diversity of industrial applications involving magnetism. For some applications, modeling only electromagnetic phenomena is insufficient; modeling other physical phenomena, especially product flow in separation applications, is also necessary.

Finite Element Modeling (FEM) is a mature method for modeling and analyzing physical systems, such as those in high-tech manufacturing, aerospace, and the (petro)chemical industry. The main driver for its use is to reduce the time and cost spent on prototyping and testing. It is used to model electromagnetic, fluid, and thermal flow phenomena and to perform mechanical strength calculations. Using the finite element method, basic physical equations in the form of partial differential or integral equations can be broken down into multiple small elements of interest, dividing the system of interest into many small elements. Although typically computationally more expensive than other methods, it can also lead to more accurate results.

Goudsmit Magnetics was founded in 1959 and is a company with approximately 140 employees, headquartered in Waalre, Netherlands. It generates (electromagnetic) magnetic systems for a.o industries such as food, automotive, and recycling. Goudsmit has been using FEM for many years to analyze and optimize its systems. The main reason is that, in addition to reducing prototyping and testing costs, using this tool allows for relatively accurate performance predictions. It has become an important means of product development and thus plays an increasingly important role in maintaining competitive advantage.

For several years, Goudsmit has used the FEM software package COMSOL [Co18], largely due to its ability to combine different physical domains. In particular, this capability allows for an extended evaluation of electromagnetic systems, for example, assessing the impact of non-magnetic phenomena on the overall performance of magnetic systems, such as heat generation in coil-related applications and the influence of flow characteristics on the efficiency of magnetic separation systems.

One of the purposes of this article is to introduce how FEM is applied in companies specializing in electromagnetics, such as Goudsmit. Another purpose is to provide an idea of the various electromagnetic applications handled by such companies. To achieve these goals, we first provide a brief introduction to FEM for electromagnetic system applications, followed by a discussion of many FEM applications encountered in daily practice. These applications represent both internal product development and optimization projects, as well as system evaluation and optimization for external customers.