Magnetic filtration can be used in almost any environment where ferrous and paramagnetic contamination of a liquid is a problem. In the metalworking and finishing world, this applies directly to the filtration of coolants and cleaning fluids. This environmentally responsible method helps fluids to retain their essential properties for extended periods and allows ferrous contamination to be collected for recycling.
This filtration can also help efforts to increase a shop’s productivity. Because fluid does not flow through filter media, flow is uninterrupted. Even when the filter is full, there is no blinding or risk of burst filters that would cause downtime. Overall, magnetic filtration can lead to longer lasting fluids and lower operating costs. But beyond these benefits, this shop also notes that the process helped attain the surface finish that customers required.
Finishing the Job
Pro Cut Tooling Ltd., located in Hull, U.K., is a manufacturer and re-conditioner of precision carbide cutting tools for woodworking, plastics and engineering industries. As part of its continuous improvement policy, the company recently turned to Eclipse Magnetics to meet its surface finish requirements on its cutting tools. Eclipse specified its Filtramag magnetic filtration system to help Pro Cut achieve high quality “mirror” finish and also provide some significant operational efficiencies.
After reviewing the filtration systems used on Pro Cut’s Walter Helitronic Power and ANCA RGX and WGX grinding machines, Eclipse engineers determined that high volumes of ferrous particles were being circulated in the oil, and the build-up of contamination was requiring excessive regular maintenance and adversely affecting the product finish.
Filtration systems with machine tools can be inadequate for ensuring a “super-finish” on a machined part. Traditional barrier filters are limited by particle size, which results in quantities of ferrous contamination remaining in the fluid circulation. These particles accumulate around the grinding wheel, causing surface damage to the part and reducing accuracy.
Filtramag FM2.5 units were fitted to enhance the existing filtration. The system features high intensity magnetic rods and is designed to ensure that fluids have maximum exposure to the rods on their flow path. The system is able to extract ferrous particles down to sub-micron size, thus ensuring the grinding contact area is kept free from contamination for longer periods. For Pro Cut, each Filtramag unit extracts 2 kg of carbide particles every week and, in doing so, ensures a “mirror” finish can be achieved. The high intensity rods ensure maximum removal, even though carbide only has 20 percent magnetic permeability compared with mild steel.
Filtramag has also been instrumental in creating several operational and cost saving benefits at the Pro Cut site. Prior to installing these cleaning units, each machine had to be cleaned on a weekly basis to remove particle build-up from the grinding wheels and polishing heads. This process caused 2 hours of downtime. The cleaning process now takes place on a monthly basis during routine maintenance. In addition, the main holding tank previously needed to be cleaned every 6 months, resulting in a full day of downtime each time. Results to date suggest that Filtramag will reduce this frequency to every 18 months.
Pro Cut has also shown a significant increase in fluid life, leading to reduced fluid costs. The company had been going through 220 liters of fluid per machine every 2 years. The company expects the same amount of fluid to last for 5 years because of maintaining fluid quality for a longer time.
In addition, the Walter Helitronic machine is fitted with a demisting extractor system. The filters on this system previously needed to be changed every week because ferrous particles would contaminate the mist. Current results show that the life of these filters has increased by as much as 10 times.
Steve Weymes, production director at Pro Cut, says, “We are delighted with our investment in Filtramag. It has provided several production efficiencies. We pride ourselves on premium quality, and the Filtramags have been vital for satisfying the high specification quality standards of the specialist sectors we serve.”
Using high performance rare earth magnetic material and pole concentrator technology, the Filtramag offers an 11,000-gauss magnetic performance. The system is capable of attracting submicron magnetic particles and can be used on inline pressure feed lines as well as gravity-fed systems. The technology is applicable for grinding, honing, lapping, boring and fine detail machining operations.
Filtramag is available in two models for maximum flow rates of as much as 500 liters per minute. Particle laden fluid is introduced via the inlet port. It then passes six high intensity magnetic rods where the particles are attracted and held, allowing clean fluid to exit via the outlet port. The system produces a dry “cake” of filtered scrap that can be easily disposed.
Even when fully saturated with contamination, the system does not build up the back pressure that causes burst socks or cartridges. The configuration of the magnetic rods ensures that pressure is always maintained.
To eliminate maintenance, the system is constructed of three separate parts (securing band clamp, lid and filter vessel) that do not move. High intensity magnetic cores of the Filtramag consistently remove sub-micron magnetic contamination, which improves surface finish, extends fluid life and increases overall component accuracy.