Forging Die Machining Spurs Innovation at Walker Forge

In an industry as old as forging, most wouldn’t think that technology and new ideas play an important role. However, as global competition increases, only the best survive.

At Walker Forge of Clintonville, Wisconsin, their skilled labor force is relied upon to bring new and innovative ideas to the table, helping the company stay at the crest of emerging die machining technologies and continuously shaping the way it serves its customers. By embracing new technologies, Walker Forge is able to provide customers with the highest level of quality by producing its own forging dies quickly and accurately.

“Our die shop’s only customer is our forging department, so the die machining capabilities we have directly impact Walker Forge’s overall business,” says Mike Olenski, Impression Die Shop Engineer/Supervisor. “We have to deal with lead-times often under a week – so relying on outside shops isn’t an option. We have to do it ourselves quickly, efficiently, and always to spec.”

To accomplish this task, Walker Forge has transformed itself over the years, adapting to new ways of doing business. The newest addition to this transformation is high speed die machining capabilities.

Years of Experience Pay Off

From its beginnings as a family owned forging company in 1950, Walker Forge has served all types of forging customers including the transportation, energy, agriculture, and construction industries. The majority of forgings produced are comprised of carbon alloy and stainless steel.

Walker Forge is still family owned and has grown to 300 employees, serving hundreds of customers. Since the early 1990s, the company has been designing and building its own forging dies at this Clintonville, Wisconsin location.

“What makes Walker Forge truly different is the knowledge and ingenuity that flows through every department of our facility,” says plant manager Rick Recktenwald. Walker Forge is very participatory in its style of management, with self-directed work units across its 24/7 operations.

“We’re not like most manufacturing companies, where very few make all the decisions and are tasked with creating the big ideas. Our mentality is to encourage everyone in our company to come forward with new ways for improvement and it has paid off every hour of every day.”

This mindset has led to healthy and strong engagement with the work force at Walker Forge, based on bonds of trust and respect. Management at many other companies wouldn’t consider leaving their shifts run with little direct supervision. Employees at Walker Forge are trusted to uphold the quality work for which the manufacturer has become renowned.

An employee idea: High-Speed Machining

In 2000, employee input led to a switch from graphite electrode based electric discharge machining (EDM) sinkers to high speed milling. It had become apparent to many on the shop floor that developments in high speed machining technology had advanced to the point to which milling could achieve accuracies previously held only through EDM, while increasing the speed of production.

When it came to finding a high speed milling machine for their shop, Walker Forge knew they needed something fast, accurate, and completely reliable.

“In order to operate high speed machining equipment properly we knew we would need quality, in-depth training from someone who understood die production and how to acheive the details we need to produce using a milling process. Some of our employees had been exposed to Makino’s training in the past and recommended we check it out,” says Olenski. “We decided to purchase a GF 6 vertical machining center. Makino helped us with the application set up and provided training at their Die Mold Technical Center in Auburn Hills, Michigan. Within two weeks we had trained employees making chips and producing dies. It was a pleasant change from a typical installation, which often involves us fighting installation and operational problems instead of actually learning a new machine.”

“The training at Makino’s facility was incredible,” adds Recktenwald. “After completing the training we saw noticeable differences in our programmers’ confidence, and, in turn, more efficient tool paths and desired dimensional accuracy and, most importantly, repeatability.”

Almost at once, the high-speed machining direction became obvious, as dies took a fraction of the time to produce in comparison to those still being EDMed. The superior accuracies of the machine led Walker Forge to assign its more complex die designs to the Makino.

Walker Forge decided to diversify their investment in Makino machines by adding a SP64 wire EDM to their shop floor in 2003 for difficult to machine, flat parts that required high accuracy.

“We were tired of sending out parts we couldn’t produce,” said Olenski. “The SP64 enables us to hold accuracies within a ½ thousandth, eliminating the need for many grinding and secondary operations.”

“The addition of the SP64 allowed us to use some innovative design techniques that would divide the process between the vertical mills and wire EDMs when necessary,” comments Olenski. “This new strategy, in combination with HEAT technology on our Makino wire EDM, allowed us to cut a challenging forging die with tight cavities and tight tolerances 30 percent faster than before, vastly improving the manufacturing process.”

Since then, Walker Forge has continued to invest in Makino with purchases of a second GF 6 in 2004 and S56 vertical machining center and MCC 2013 horizontal machining center in 2007.

“The high speed milling of our Makinos has completely changed the way our shop operates,” says Olenski. “At one point, mills were used purely for roughing and graphite electrode production, but today they are critical in every application, especially in hardened dies approaching the 60 Rockwell range.”

“Our best turn-around times have gone from several weeks to one week or less, and sometimes even as short as a few days,” adds Olenski. “This also creates the added benefit of increasing our capacity, or in other words, our forging dies per man-hour.  In some cases, one highly skilled operator can run as many as 4 machines at a time.”

“The shop floor here looks completely different today. Less than a decade ago our floor was covered with tracers, sinkers and grinding benches…today we only have one of each,” says Olenski. “We keep them around mainly for forging dies and features that can’t be made any other way. Our selection of milling machines, however, continues to grow since our purchase of the first Makino. The forging dies we’re making today are much more complex and would be difficult or, maybe even impossible, on anything but our high speed machining centers.”

The Forging Dies Now Being Made

Walker Forge’s switch to high speed milling led to increased dimensional capability and repeatability, as well as an increase in forging die manufacturing capacity. With skilled labor becoming more difficult to find, the increased capacity to build complex forging dies allowed Walker Forge to support its overall growth strategy without the need for additional skilled labor in the tool room. Complex impression dies, ranging from six inches to two feet, requiring smooth, consistent surfaces with no transition lines make the rigidity of the Makinos a necessary feature for high volume, high quality forging die production.

“Using high speed milling has saved us a lot of time and greatly simplifies and speeds up our process,” says Olenski. “We’re creating forging dies faster now, with lead times reduced, in some cases, by as much as 75%, and the dies we’re making are of a much higher quality, according to our design engineers.”

“Our engineers also tell us that the forging die life has been increased, which is a huge savings for our production as a whole,” says Recktenwald. “Add the overall cycle time savings and that means that, not only are we producing better products, but we’re doing so at a lower cost. These improvements have helped us offset the enormous increase in the cost of hot work tool steel, thereby shielding our customers from some of the economics of the steel industry.”

Flexible Die Machining

The Makino MCC 2013 provides capabilities to Walker Forge that go beyond precision die sinking. Its ability to handle large forging press components helps keep maintenance, repair and overhaul timing to a minimum. Mechanical press parts are customized pieces and the skilled repair personnel provide critical sizing requirements to the machinist. The on site communication helps advance first time quality of the components and keeps the inherent cost of logistics timing at the absolute minimum. Machine repair is all about knowledge, effort and lead times and the MCC2013 gives us a much better chance to positively impact the results.

“We found that we’re very competitive… whether it’s die machining or repairing press parts, and that’s without applying the cost associated with zero defect quality, freight and timing.” says Olenski. “We’ve had limited success outsourcing due to other people not knowing the business of forging itself.  We’ve never run across a piece of equipment that can one day cut amazingly accurate dies for production, and the next save you from going down for weeks by repairing another machine’s giant parts. It’s an added benefit we didn’t expect, but have come to rely on.”

In addition to the machine being flexible, its fourth-axis allows Walker Forge to machine dies it was incapable of manufacturing before. And because it’s a horizontal machining center, the huge amounts of material removed from large dies aren’t an issue.

“We’re really a vertical shop, but the horizontal has added a whole new bag of tricks as to what we’re capable of,” adds Olenski. “We’re really just discovering the capabilities of this type of production, and have hopes that it will be our next step forward in the company’s transformation.”

Better parts, faster

With shorter lead times and more forging consistencies, Walker Forge can produce better parts, faster, and is competing more aggressively in an industry that is being bombarded with global competitors.

“Thanks to the motivated and innovative minds of our people, and a more participatory working environment, we’ve been able to retain and grow long time forging customers, all while bringing in new forging and machining customers” says Recktenwald. “We will continue to stay on top of new and emerging technologies like high performance, high speed machining and use these technologies to continually advance our company by providing the best service to our customers.”