The Foe: Ferrous Metal

Small ferrous and nonferrous particles (those below 10 microns in size) are among the most damaging contaminants in the machining industry, and therefore must be removed.

Situation: Ferrous metal particles below 10 microns in size remain in fluids and damage equipment.

Industry research states that iron and steel particles below 10 microns in size are among the most damaging contaminants to the machining industry.

Fluid contamination reduces the operational life of components such as cutting tools and pumps. It also produces subquality finished parts. Another significant and costly problem associated with this contamination is reduced cutting and cooling fluid life. Bacteria lives off iron particles under 10 microns, creating a smelly, degraded cutting cooling fluid.

It also should be noted that when components are machined, coolant can be contaminated with metals at submicron levels and embed into parts and the machine.

The other serious issue in the production process occurs during part washing. The wash solution can become contaminated with the same fine ferrous metals (under 10 microns), which stay attached to the parts after cleaning and are sent off to the customer. The products are then assembled, for example, into complete engines and gearboxes, bringing wear contamination with them. This decreases the product’s life.

It also degrades the parts-washing solution, reducing its operational life. Most parts washers employ bag filtration to remove contaminants, but many are efficient to only 40 microns, missing all the particles under this size.

Depth media filters and bag filters typically are made of paper, polymer, or fiberglass, which enables “worm holing” and “channeling” to occur. This happens when metal contaminants cut holes through the filter media and the rest of the residual contamination follows the path of least resistance, traveling through the hole and reducing the filter’s efficiency.

Traditional ceramic magnetic filtration does not have the ability to filter contaminants smaller than 10 microns with any efficiency because of the magnet’s relatively weak magnetic field strength. Ceramic magnetic filtration also is susceptible to vibration and temperature fluctuation, which can cause the ceramic to crack and distribute fine, very hard ceramic particles throughout the system.

Resolution: Rare-earth magnetic filtration removes particles under 10 microns.

One Eye Industries, Calgary, designs and manufactures rare-earth magnetic filtration units that use a powerful magnetic radial field to remove ferrous and nonferrous submicron contamination with minimal flow restriction.

Nonferrous contaminants also are attracted to the magnetic field through static adhesion. This dual filtration design comprises a stainless cloth depth media filter element and magnetic filter for coolant and cutting fluid applications.

Case 1: Rejected Parts

Linex Manufacturing, Guelph, Ont., was having parts rejected because of inadequate cleanness, even after they were passed through three washing systems. Hydra-Fab Fluid Power, Mississauga, Ont., suggested installing a magnetic filter (scrubber) before the existing filtration system.

Before the unit was installed, the company was reporting 22 mg on the patch. After it implemented the new magnetic separation unit, the contamination count was reduced to 9 mg. Since the installation of the scrubber, the life of the element has been extended to more than two months from three weeks, and product rejection has been eliminated.

Case 2: Contaminated Parts Washer

Linamar, Guelph, Ont., determined that its Hotsy® parts-washing station was contaminated with fine ferrous particles (under 10 microns in size). This posed a problem because the company’s nominal filter bag was rated to only 40 microns. The company considered a secondary washer to meet its specifications, but eventually decided on enhancing its existing filtration system by installing a magnetic filter inside the filter bag.

The new setup traps wear particles— even at submicron sizes— eliminating the need for a secondary washer. This made the need for a new machine redundant. The parts washer is now achieving cleanness levels beyond specifications.

Case 3: Dirty Coolant

A missing drum filter caused Husky Injection Molding Systems to select a magnetic scrubber system for removing significant amounts of metal contamination from its 700-GPM coolant/ cutting fluid distribution system.

One Eye Industries suggested using its environmentally friendly filtration system, which eliminated the need for large roll-out cloth filters. This saved space in the manufacturing facility and reduced the time required to clean the filter.

With contamination removed, even at submicron levels, the coolant and cutting fluids are cleaner, resulting in the retention of the fluids’ ability to cool and lubricate and extending their life.

www.oneeyeindustries.com