Meet Sune Backman, Director of Engineering of Transor Filter USA.
The very first EDM machine sold in Sweden was an Agietron and the year was 1955. At that time the only dielectric oil available was one that was used in electrical transformers and it was filtered by a unique system called Transero. It was only natural that the same dielectric oil and filtering system should be applied to that first EDM machine. The result was that the very first EDM machine in Sweden was 20 years ahead of its time by being equipped with a Transor Filter. Sune Backman, Director of Engineering of Transor Filter USA, told us the interesting story of how this original transformer filter system was perfected for the EDM machine and is now "transforming" dirty EDM dielectric into crystal clear oil with a one micron clarity-all over the world- without the use of cartridges.

Sune Backman was born in the northern part of Sweden and always had an interest in anything mechanical. An avid perfectionist, he eventually owned a mechanical repair shop and expanded his interests by trying to improve any device he ever worked on. He also acquired a marketing background and the combination of these two talents laid the groundwork for a very successful, international EDM career. In 1974, he joined with a partner that was familiar with the EDM process, and they decided to purchase the filter company and to perfect it for EDM use. This took many years of hard work and determination by both partners to bring the Transor Filter to where it is today.

The Heart of the System is a Small Paper Disc.
Sune told us, "The filter element is composed of a stack of special paper discs .003" in thickness and 1-1/2" in diameter with a center hole. 9,000 of these discs are assembled on a rigid, fluted rod approximately 36" long and are compressed tightly together. The assemblies are referred to as the 'filter sticks.' Each filter vessel contains 61 of these sticks which translates into over one half million of the individual paper discs in each vessel," Sune stated.

"The way it works is - the oil flows from the O.D. to the I.D. of the filter sticks and the debris is deposited on the outside surface of the sticks (the edges of the paper discs). Referred to as edge filtration, it is highly efficient and the results are dielectric oil filtered to a one micron, (40 millions of an inch) clarity," Sune explained. "Periodically, the filter sticks are automatically cleaned by forcing compressed air through them from the I.D. to the O.D. and the dirt is blown down into a storage container where the oil is drained off. The entire unit including the filter sticks is guaranteed for one year, however the life of the sticks is approximately 15,000 working hours before they require replacement. At 40 hours/week, 50 weeks/year, this translates into 7 1/2 years, however there are many cases of the filter sticks lasting as long as 40,000 hours (20 years use) and the longest case is estimated at 60,000 hours (30 years use)! The only maintenance required is to check the level of the dielectric oil periodically and dispose of the dirt container as you would a vacuum cleaner bag, about once a month on average," Sune stated. back to top

It Sounds Too Easy
You might think that a filter system that already existed would be easy to perfect for EDM use, however that was not the case. "Compared to filtering the oil in a transformer, the dirt that is generated by an EDM Machine is totally different. It is not consistent in its type or quantity and the filter must be efficient in every case," Sune explained. "Hundreds of different materials are EDMed today which was not the case back in 1955 when the filter was first applied to EDM. Add to that the different electrode materials and dielectric oils used around the world and you come up with thousands of different filtering situations to take into account. That is why we only pursued the Scandinavian market for many years in order to be close by when the new problems surfaced. We also used this time to acquire worldwide patents on our new developments. Staying close to our home market worked out well since our new company couldn't afford extensive traveling and I couldn't speak a word of English besides hello and goodbye," Sune laughed as he told us.

The results were that we captured the Scandinavian market with 95% of the EDM machines being equipped with Transor Filters while we perfected the system. In addition, since the Swedish EDM users favor the use of graphite as an electrode material, our filter was prepared for the U.S. market where similar conditions exist, he explained. "If we had started in Germany, for instance, where copper is favored, we would have been in for an unpleasant surprise when we brought our filter to countries where graphite dominates. We see more and more graphite being used throughout the world because of its efficiency and our filter is equally efficient in coping with its use," Sune stated proudly. We would also like to say that Sune is also efficient in the language department and today he speaks perfect English along with several other languages.

Transor Filters Are Used All Over the World
"We feel that we were ahead of our time since the Transor Filter System automatically cleans and reuses the filter sticks over and over, and you only dispose of the debris. In light of the environmental concerns in every part of the world, this type of filtration is generating a great deal of interest," Sune stated.

"We work with EDM companies all over the world in different ways," Sune revealed. "For instance, ONA EDM in Spain started to build our filter under license in 1975 and they are still building them today. They in turn export their Transor equipped EDM machines to a large world market especially France, Germany, Italy and South America where they enjoy a large market. ONA was our first venture outside of Scandinavia and we estimate it resulted in more than 10,000 Transor units sent all over the world," Sune revealed. Since then, Transor has established working relationships with Mitsubishi, Hitachi, and Makino who all build the Transor system under license. "We still produce all of the filter sticks in our factory in Sweden since the composition and texture of the paper disc is so important in maintaining consistent quality and predictable filtering life," Sune explained.

In 1977 the first Transor filter was sold in the U.S. for a multiple EDM installation in Massachusetts and Transor's success has escalated year after year since then. Sune told us, "We concentrate on EDM installations of three or more machines since justification of the sale to the customer is important, and the more the machines the faster the pay-back occurs. When we make a proposal on any installation, we always estimate what the payback period will be. While the Transor substantially reduces a company's existing maintenance cost, the major advantage of the system is a general reduction in machining time when EDMing with oil filtered to one micron. Machining efficiency can be improved up to 35%. When translating this figure into dollars, many customers are surprised at how fast the payback is. They have a tendency to think we are exaggerating.
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