EWT of Rockford, Illinois, is a company that specializes in EDM and other precision machining techniques. Recently, they celebrated their 25th year in business, accomplishing some of the most challenging work ever done by Wire EDM. We recently visited EWT and spoke with Don Busehros, the company's President, and asked how they got started in business. He explained that after serving a four year, 8000 hour Tool & Die apprenticeship, he worked at several different tool shops in the Rockford area, gaining a variety of experience that would eventually prove to be extremely valuable.

As he progressed on the various jobs, he eventually found himself coordinating a large tooling project, from the beginning to the finished product, for a well known international company. During a visit to a shop that was involved in the project, he saw one of the first Wire EDMs in the U.S,, that had just been delivered. Watching it run, he couldn't believe his eyes, and he was immediately convinced that this process would revolutionize the entire Toolmaking Industry.

Coincidentally, that same night, a friend of Don's showed him a brochure for the very same Wire EDM he had seen that day. They both agreed that they had to have one, and that they should start a business in order to do it. The serious problem facing them was, that 25 years ago, the price of the EDM machine was $106,000, which in today's dollars was well over $1,000,000. And back then, the machine was NC tape controlled, without linear & circular interpolation, and it cut at the rate of only one square inch per hour.

Buying The Wire EDM

Since, at the time, Wire EDM was so radically different, very few tool shops wanted to invest in a machine for their own shop. However, to be a shareholder in a machine, and to have their work done for them by skilled Tool & Diemakers, proved to be an excellent low-risk method to learn if the process would be successful. This shared arrangement worked so well, that within one year, EWT had three Wire EDMs that were kept constantly busy. Since the Rockford tool shops were doing work for customers all over the country, the word was spread that Wire EDM was the way of the future - and was here to stay.

Wire EDM vs. Jig Grinding EWT has been doing both Jig Grinding and Wire EDMing for many years, and has become expert in both machining technologies, Determining which process was the best one for a specific job was an easy decision for EWT The parts stacked in front of the Wire EDM are an example of a long running, high precision project that was once considered a Jig Grinding fob by the end user - that is, until they visited EWT Today, the job is being accomplished day after day by the Wire EDM, faster, more accurately, and requiting no inspection by either the EDM operator, or the end user.

For about ten years, EWT continued to do the Wire EDM work for many of their original customers. However, one by one, most of them purchased their own Wire Machines and did their work in-house. In retrospect, EWT was largely responsible for a nationwide acceptance of the process, and for a great number of the Wire EDM machines being sold.

EWT Today

25 years ago, EWT did mostly stamping dies, which is ideal work for Wire EDM, and relatively easy. However, when Diemaking shops all started buying their own Wire EDMs, the type of work changed to a wide variety of more challenging, high risk jobs, such as cutting details into very tall, and very expensive finished gears.

Don explained that they find it rather easy to stay busy, mainly because they have a tendency to take on difficult jobs that other shops shy away from. Many of these jobs have high risk factors, however, by successfully completing them, they maintain their reputation as a shop that can be depended upon. Don pointed out one job that was running that required details to be EDMed into some very tall, and very expensive parts.

Highly accurate gauges (shown in the fore ground) are being produced with the use of an Imperial Newbould precision indexing fixture, mounted in a Wire EDM. The part requires 21 equal indexes (17 deg., 8 min., 34 sec.). The fixture has a unique internal mechanism, capable of indexing to one second. It was invented by R. J. Newbould, and has been displayed in the Smithsonian Institute in Washington DC.

He told us that at first they did mostly stamping die work, which is relatively easy, with flat die blocks, strippers, punches, etc. As the die shops bought their own machines, the only work available to them became much more challenging and difficult, but very interesting and educational. Over the years, EWT has taken on, and accomplished jobs that were considered impossible to do by Wire EDM, and some are still considered much too difficult to take on by other shops. Don explained that there are a large number of Wire EDM shops that compete for the easy work, however, competition falls away rapidly as the work becomes more difficult.

Jig Grinding vs. Wire EDM

Don explained his reasoning to us about the Wire EDM being able to do a job more accurately than Jig Grinding. First, whenever there is a wear factor in a machining process, an inspection must be performed. In almost all machining methods, there is wear on the tool that could show up in the finished product, however, not with Wire EDM. And the cutting tool, the wire, is accurate to a few millionths of an inch. Heat is also a detrimental factor on Jig Grinding, yet on a submerged Wire EDM with temperature controlled water, heat is not a factor. He also said that today's EDM machines are extremely stable and accurate, and the absence of machining pressures in Wire EDM, insure that the parts reflect the builtin accuracy of the machine. This long running job turned out to be a complete success, with no inspection necessary by EWT or the end user, other than the use of one functional pin gauge.

Don Busekros, President of EWT (on the left) has a conversation with Richard Raucci, owner of Mid-States Machine Tool, the dealership responsible for Fanuc EDM in that area, along with several other high quality machine tool lines.

Don pointed out that not only does the Wire EDM offer the best accuracy, it also retains it. That is, if the parameters don't change - conductivity levels, flushing pressure, speeds and feeds, etc. - then the machine will duplicate the work hour after hour, day after day, week after week. If normal Wire machine maintenance is performed on a timely basis, the job should just continue to run without the need for inspection of the results.

Engineering The Job

Over the years, EWT has taken on projects that require a great deal of engineering before any tooling or hardware can be designed and built. Engineering the job has always been Don's strong suit, and he confessed that it's the part of the job he enjoys the most. He showed us several different gearing projects EWT had completed, that required the development of eccentric, elliptical or specially configured gears, along with the necessary tooth shapes. Several of these examples are pictured here, to give the reader some idea of how valuable the Wire EDM is in developing and building special gearing.

Another unusual project we saw during our visit to EWT, was machine used to trim window blinds to size. This is used by all the major department and hardware stores that sell window blinds. Don explained that the machines were being assembled by a company that used temporary workers, and the component parts were being produced by random shops at the lowest possible cost. EWT was one of several places that was contacted and asked if they wanted the job of assembling the units. After inspecting one of the machines, Don said they would take on the project only if they could also build all of the parts. He reasoned that, if EWT built the components themselves, then they would spend two hours assembling a two hour job, not ten hours on a two hour job.

Five years ago, an opportunity presented itself to EWT, where they were able to take over the complete manufacturing of the popular window blind cutting machine, pictured here. So far, they have built over 5,000 of the units that are in use by the majority of department and hardware stores all over the country. EWT is also taking on the job of rebuilding the older models already in use.

A Question Of Recast

Having been in the Wire EDM business for 25 years, Don has had to deal with the subject of recast in many instances. As EDM technology advanced, it became less of an issue, however, where critical applications are concerned, such as parts used in aerospace equipment, recast is still a valid factor and must be addressed.

Don explained that they do a great deal of prototype work, such as engineering projects for one particular company heavily involved in aerospace work. That company has a stipulation that any EDM work, if it goes into an aircraft part, must have no recast whatsoever, with a guaranteed 3X metal removal of the thickness of the recast layer. However, many times Wire EDM is used as a last resort, because there is no other way to produce the part, and no positive way to remove the recast layer. And if laps are used, there is no way of knowing if more material is removed from one side or the other.

Recently, EWT received a project, and Don explained to the company that he could not guarantee removal of the recast layer according to their stipulation. However, he suggested trial EDM machined parts, with the absolute minimum of recast, then cut apart and checked by the end user's metallurgy department. The trial parts were cut on one of EWT's Wire machines that incorporates full time AC circuitry. They employed several skim cuts that would insure the best results possible, and sent the parts off for metallurgical testing. The test results showed NO recast layer, and they got the job. Don commented that it would seem improbable that EDM could cut with no recast whatsoever, however, if metallurgical experts say so, it must be true.

In Retrospect

We asked Don to sum up his 25 years in the Wire EDM business. Among other things, he spoke of all the improvements made in the equipment in both speed and accuracy, and saiJ that what they accomplish with 18 machines today, would take at least 90 of the original models. He also said that using today's EDMs, he has never had to turn down a job because of the capability of his EDM machines, and they have always performed exactly as needed.

Designing and building special gearing is a favorite project of Don Busekros, and the elliptical gears shown here in their different positions, are a typical job he has accomplished. Can you imagine how difficult it would be to do a job like this without Wire EDM?

Looking to the future, he recently changed the structure of the company by adding two partners. Long range plans include his gradual retirement with no particular deadline in mind. He will concentrate on training people to take over his duties, and also bring on a full time salesperson with the intention of getting into new areas and new product lines. A great deal of growth is expected, which should result in new larger quarters for the company.

Another example of speciality configured gears engineered by EWT, and built using Wire EDM.

During our visit, Don showed us so many innovative applications for EDM, that space constraints prevent us from showing and explaining them all. We promise that, in the future, we will pay another visit to EWT, and I am certain that they will again show us more than we have room for. When we wonder how the EDM process became so successful, we realize that it's largely because of companies like EWT and people like Don Busekros, accepting challenges and applying the equipment in ways that even the machine manufacturers never dreamed of.

This article brought to you with the permission of EDM Publications, Inc., publisher of EDM Today, with offices at 230 West Parkway, Unit 3-1, Pompton Plains, New Jersey 07444. Copyright © 2000 by EDM Publications, Inc. Our thanks to the staff of EDM Today for their assistance. -MMS