Medium to large machining, fabrication build and rebuild
3611 Woodburn Avenue
Cincinnati, Ohio 45207

How to Win with the World’s Largest Machine Tools


Dynamic Industries Profile Article as published in the March 2007 issue of Shop Talk

By Chuck Lohre

Meeting customer needs amid a changing world market for large-part job shop machining is not only an ongoing challenge, it is the challenge. Cincinnati-based Dynamic Industries’ has taken on the challenge with its versatile employees and flexible machine tool selection. Nearly 20 years ago, Phil Mitchell, a machine shop owner in nearby Dayton acquired the 150,000-square-foot G. A. Gray facility building and its contents in the heart of Cincinnati. The enormous building provided space necessary to house some of the world's largest machine tools and the chance to work with global heavyweights.

"Big Parts for Big Industries"
“We do jobs for just about everybody,” explains Mitchell. With 40-foot high bays and easy truck access, Dynamic is perfect for large-scale work. Because they specialize in work beyond a 40-inch cube, they have clearly bypassed local markets vaulting onto the global stage. Big shop capability aside, Dynamic wins customers because Mitchell strives to deliver on customer expectation, not just what they asked for. That might mean recommending a different machining process. For example, should a customer bring in a piece for grinding but planing would be less expensive, Dynamic will explain its recommendation. They’re also able to help engineers. It’s no secret big shops are quickly disappearing, which has led engineers to design large-scale equipment in pieces that smaller shops can handle. Dynamic has the experience to determine if such an arrangement will produce the desired outcome.

Mitchell also works with customers to redesign fabrications with poor weld designs or ones that are twisted due to bowed tubing. Holes might need to be relocated to an area with sufficient material. There are those shops that would have done as asked and delivered a "correct" yet inadequate part for end use. Not Dynamic.

Evolving Flexibility
While one might think Dynamic’s inventory wouldn't change much, nothing could be further from the truth. The rapid change of pace must match world, not just local market conditions. Dynamic maintains a large number of machine tools – a number of which came with the facility. Among the equipment Mitchell particularly sought was one of the largest planer mills ever built; one constructed in his very shop, a Gray DH. Given the nickname “Jumbo,” it can handle nearly anything up to 40 feet long, 10 feet high, and just under 14 feet wide. “They started calling it Jumbo back in the early ‘60s when it first came into operation,” recalls Mitchell. Much fanfare surrounded the machine’s launch. Gray even brought in an elephant to stand on the machine’s table to drive home its enormous size to the delight of the employees and their families.

Since 1987 when Mitchell purchased the facility, he’s added vertical turning lathes, grinding machines and horizontal boring machines. Some were returning Gray machines. “Phil’s very fond of Gray equipment,” says Kim Richendollar, Dynamic’s office manager. “They’re very heavy, beefy machines. Very stable.”

Along the way, a few vertical boring lathes with 20-foot diameters were added to Dynamic’s machine tool selection, followed by a 10,000 sq. ft. expansion to accommodate one of the world's largest combination vertical and horizontal boring machines. “We place machines where they’re most effective," says Mitchell. "If the floor needs to drop 10 feet to compensate for efficient placement, so be it. If the end of the main bay has to be expanded, okay."

While old Gray machines occupy a special place in his heart, Mitchell’s not married to them because a changing world market demands nimbleness. Large vertical boring mills are gone now and the mix of grinders and horizontals are different, but Dynamic makes sure customers are constantly informed of its new machines and capabilities.

“Phil’s very savvy about what type of ‘iron’ to buy and when to buy it,” observes Dynamic’s Richendollar. Should there be downtime or an increase in a machine's value, some machines are sold. Keeping debt low and maintaining flexibility to purchase superior equipment when it becomes available is one of the keys to Dynamic's success. For example, machines are considered for replacement if a larger CNC or multi-axis machine becomes available.

How They Do It
Large parts require special treatment from start to finish to maintain quality. Dynamic’s recipe, for instance, relies on a number of logical steps. “Parts must sit anywhere from 24 to 48 hours before we can touch them,” explains Mitchell. That’s especially true in winter when trucked parts arrive quite chilled. “Before we can do anything, we have to be certain the parts’ and shop’s temperatures have leveled out. Metal shrinks and moves so much with temperature changes, especially when it comes to grinding.” They don’t allow open doors while grinders are in service, for example. With temperature fluctuations, Mitchell says, “Parts can bow real quick.”

Special consideration surrounds large expensive parts. While Dynamic can’t take responsibility for integrity of castings provided, they will, however, stop operations to contact its customer if too much porosity is found in the casting or excessive amounts of sand are present.

With parts this large—for example those weighing 100,000 pounds or more—there’s only one shot and Dynamic has used Virtual Gibbs since 1998 to program directly on its CNC machines. Prints come in as DXF, DWG or IGUS files and loaded into the Gibbs program where hole locations, pockets and milling depths can be adjusted. The real-time part rendering allows a machinist to see exactly what will take place before making a single chip.

How do you hold 1 to 2 “thou” on a 100,000-pound piece? Dynamic has discovered it’s all relative. Traditionally, machine tool users have not trusted their processes, which is the reason why there’s a gauge at the end to check whether the part had been machined as expected. But for Dynamic, there is no way to put parts this big on a coordinate measuring table. Rich en dollar likes to say Dynamic’s huge jobs are at the “top of the food chain.” One fairly standard job is grinding the ways for a matched bedway and column. Grinding a 15-foot bedway posed no particular challenge for the Waldrich grinder, which has a 28-foot stroke and can accommodate parts 10-feet wide and 8-feet high. Upon completion, the operator of the Waldrich took five thousandths of an inch off the top two surfaces, and ten to twelve thousandths off the verticals. After that, the column would have its corresponding ways match-machined to the work done on the bedway. Reestablishing the relationship between the two ways, keeping them flat and parallel, is a recurring and critical function at Dynamic. The relationship of the two ways needs to be exact for reassembly. “Warren Strunk, Dynamic's production manager, takes pride in the machining,” says Richendollar. “He doesn’t cut corners.”

Good thing because a typical three-axis machine tool has more than 20 potential sources of inaccuracy. Then there are the workholding elements— fixtures, clamps, chucks, vises and jaws—that present even more pitfalls. Since many of Dynamic's parts are unique, setups are as much an obstacle as the actual machining process.

“Jumbo is great for rough cuts. It can take stock off like nobody’s business,” Mitchell explains. “We might put a large part over on Jumbo to finish all of the linear geometry then move it down to the Scheiss or the Mitsubishi (CNC horizontal boring mills), better suited workcenters because their CNC capabilities can complete all other features such as holes, bores or keyways.” The Scheiss is no small fry either with 44 feet of horizontal travel, 16 feet in the vertical and a nearly 7-foot Z axis. Like the Mitsubishi Boring Mill, the Scheiss melds well with the shop’s philosophy, which is to accommodate large parts with minimal set-ups and changeovers. The Mitsubishi CNC Floor Type Boring Mill has 49 feet of horizontal travel, 13 feet of vertical travel and an 8-foot stroke.

Dynamic likes to think outside the box. Consider Strunk who developed tooling along with Carboloy to use plunge cutting to remove 60,000 lbs. of material from a 127,000-pound forging. Plunge cutting took 12 minutes per cut and 8 hours to do the job, versus milling which would have taken 41 minutes per cut and two days for completion.

Every step is taken to ensure that the customer ultimately gets what they need, a philosophy that carries through to delivery of the job. Nothing leaves the plant that isn’t tied down and tarped. A single highway stone can ruin a perfectly ground or painted finish. Since the road is fraught with hazards it’s the reason Dynamic recommends dedicated point-to-point carriers. Sure, it’s probably less expensive to ship loose pieces with a common carrier, but considering these will likely repeatedly be transferred, the potential for damage increases each time a part is moved.

The Secret Ingredient: Qualified and Versatile Employees.
"Our niche is handling large parts with a high degree of accuracy,” says Mitchell. “To run these kind of machines, you have to have operators with extensive experience. They’re really hard to find. You can’t pick them off the street.” Mitchell explains most come to Dynamic either by recommendation from another large-part shop. And all have large part machining experience. “Even then,” Mitchell continues, “They still have to be trained for at least six weeks.”

The level of experience that is typical of a Dynamic employee usually requires many years of in-depth work on a particular machine. The dedicated operator of one of the shop’s two Waldrich Coburg grinders is extremely familiar with the idiosyncrasies of his particular charge. One operator has been running one of its Waldrich grinders since 1996. When asked which machine he worked on before that he says with a grin, “the other Waldrich.”

The 25 employees that make up Dynamic, from the machinists to the people that debur, work as a team and are part of a family. The 150,000-square-foot shop has only three maintenance personnel. With a 16-year average employment and 80 percent with at least 10-years experience, operators are assigned a workcenter and are completely responsible for its operation and performance. Moreover, 45 percent of the employees are cross-trained allowing them to move, for example, from a milling machine to a planer, grinder to a milling machine

Scheduled to Succeed
Scheduling is centrally focused on the main bay, which is 660-feet-long by 115-feet-wide by nearly 40-feet-high. Side bays focus on more normal over-size machines, such as grinders and planer mills, that don’t require heavy cranes. Bottlenecks aren't hard to eliminate when you're removing thousands of pounds off of several pieces on one machine.

When there are only a dozen jobs going through the shop at any one time: delivery, machine capabilities and customer loyalty are all taken into consideration while making scheduling decisions.

Operator flexibility also helps with scheduling since jobs can last from one to 10 days. It takes an intuitive operator to switch from working on a 10-foot-long, 60,000-pound part to a 40-foot-long, 6000-pound part. The Scheiss and the Mitsubishi can do just about anything (mill, drill, bore and tap) and these are the flagship CNC machines. The manual Gray DH can complete these tasks as well, and even though it takes too long for drilling, it's a great for rough and finish milling. A lot of material can be hogged off and sent to the Ingersoll Master Head or Scheiss to drill holes or other intricate features. A Dynamic employee could be working on a 60,000-pound bolster for a press, then to a rail system for the aerospace industry and proceed to broach components for the automotive industry all within a week to 10 days. Dynamic employees run parts for many industries; including the rebuild industry, petrochemical, machine tool manufacturing, automotive, aerospace and basically any capital goods industry needing their services.

Dynamic’s formula for success is simple. Hard work, a trained and qualified staff and ingenuity makes for a powerful mix in the large machine tool market. Another measure of success? Just how easy they make that hard work look.


Gray DH large planer millGray DH large planer mill with a 40-foot stroke, 14-foot width and 10-foot height. Notice the operator in the bucket at the end of the double arm.
Waldrich-Coburg Grinder,Waldrich-Coburg Grinder, X - Stroke 21' 91/2", Y - Width 9' 3", Z - Height 8' 2".
Mitsubishi CNC Floor Type Boring MillMitsubishi CNC Floor Type Boring Mill, X - L/R 590", Y - U/D 158", Z - I/O 95" with 75 HP, ANSI No. 50 taper spindle. Heavy-duty right angle head, universal head, extension support, slender right angle head.
Ingersoll CNC Planer MillIngersoll CNC Planer Mill: X - Stroke 28', Y - Width 180", Z - Height 39" with 98" x 138" worktables, 98" x 305" joined together. 154 ton table load capacity. 21" x 25" ram size. 120 HP vertical head motor. Fanuc control 16 IM.