FRIESS FMF 420/3 Magnetic Filter: Flux Density Comparison

A rolled-profile manufacturer uses approximately 4,000 litres of emulsion to lubricate and cool its rolls. Cold rolling generates extremely fine metallic wear particles, often below 10 µm, which conventional belt filters usually cannot capture. A magnetic filter previously purchased for a smaller emulsion system had delivered disappointing performance.

The Problem

After reading about FRIESS magnetic filtration, a maintenance employee arranged an on-site meeting. The operators were understandably sceptical because their existing filter had performed poorly. Inspection showed that it was unnecessarily difficult and time-consuming to clean.

Complex Cleaning

Cleaning the magnetic rods of a FRIESS FMF magnetic filter during routine maintenance

Dirt accumulated not only on the outer tubes but also on the magnets inside them, making disassembly, cleaning and reassembly very time-consuming.

A Weak Magnetic Field of Only 1,500 Gauss

Low-flux magnetic-filter rod with limited capture of fine metal particles

Because the poor separation result was unusual, the magnets were measured. Their flux density was extremely low at only 1,500 gauss.

Low-cost hard ferrite magnets had been used instead of more powerful neodymium magnets. This made the filter inexpensive, but its separation performance was inadequate.

The Solution: FRIESS FMF 420/3 Magnetic Filter

After a FRIESS FMF 420/3 fitted with magnetic rods delivering approximately 10,800 gauss was installed, emulsion cleanliness improved visibly.

Product view of a FRIESS FMF 240/1 HT high-temperature magnetic filter

High Magnetic Flux Density

High-flux-density magnetic rods in a FRIESS FMF filter for capturing fine metal particles

High flux density of approximately 10,800 gauss.

Dirt Simply Wipes Off

Metal contamination captured from coolant emulsion on FRIESS FMF 420/3 magnetic rods

The supplied cleaning tool removes contamination from the magnetic rods quickly and easily.

Results

In just one week, the FRIESS FMF 420/3 removed as much contamination as the previous filter had collected in twelve months. The comparison demonstrates that actual flux density at the outside of the magnetic rods is decisive for filtration performance. High-performance neodymium magnets cost more than conventional hard ferrite magnets, but their far greater separation efficiency makes them the better choice.

When comparing magnetic filtration systems from different manufacturers, always compare the actual flux density as well as the purchase price.

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