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Shop Solutions: CNC Turning Pumps Up Business

   

The oil drilling boom has proven to be an excellent match for thermally-applied coatings and machining processes that are the specialty of Watson Grinding & Manufacturing (Houston). The 47-year-old company has built its reputation by offering turnkey manufacturing of oilfield components such as valves, pumps, and compressor parts.

The company has developed a variety of thermally-applied coating processes to solve erosion and corrosion problems plaguing industrial valves used in today's petrochemical, oil production, and manufacturing plants. During the early 1980s, Watson was heavily involved in the development of high-velocity oxygen fuel (HVOF) coatings, which later became known as "Jet Kote." In addition to HVOF coatings, Watson offers high-energy plasma, metallizing, and weld-overlay coatings.   

For industrial valves, the type of spray coating chosen depends on the application. For example, HVOF coatings are applied at supersonic velocities to critical valve components where wear and erosion are serious problems. Tungsten carbide, cobalt, nickel, and chrome matrixes and chrome carbide coatings are all applied with this process.

Other coatings, such as chrome oxide, aluminum oxide, titanium dioxide, and zirconium oxide are used where dielectrics, thermal barriers, and corrosion resistance are required.

What makes Watson Grinding & Mfg. unique is its ability to machine, spray coat, and then finish valve components (by grinding, lapping, or honing) all at one facility. This allows the company to turn parts around quickly and reliably at competitive prices.

Valve components are made from raw material or rebuilt from existing parts. Watson Grinding repairs most ball-valve components, including chrome and nickel-plated parts. With today's machine tools, the company can hold tighter tolerances and apply the coatings best suited to a particular job.   

The company has added the role of OEM to its corporate profile. In recent years, it has begun manufacturing ball valves of the company's own design, and has established a separate entity, Watson Valve Service, to manufacture this line of severe-service ball valves.

Customer demand was a major influence in Watson's decision to become an OEM. When Watson determined that the design of its new valve line should be customer-driven, management interviewed a large cross section of its customers. The list included 116 companies in the petrochemical, refining, mining, pulp and paper, and power industries.

The responses were unanimous—customers wanted a valve that could stand up to their absolute worst applications. This meant a valve that could handle abrasive and corrosive environments, harsh chemicals, and extremes of temperature, pressure, and stress.

Armed with a wealth of customer suggestions and a blank sheet of paper, Watson Valve Service designed a severe service valve that is, in their words, a real "Texas Bad Boy." The new valve was introduced to industry about five years ago, and Watson Valve Service now rivals its parent company, Watson Grinding & Mfg., in total sales. If pending contracts come in, it will easily surpass it.

Gearing up to serve this market niche required a significant investment in capital equipment and manpower. The company sought vendors that had a reputation for quality and were prepared to act quickly.

For CNC turning machines, the company selected Romi Machine Tools Ltd (Erlanger, KY). Currently Watson has six machines:

  • A G260 for higher-volume smaller work up to 17" swing x 19" turning length (432 x 483 mm).
  • A G50HT for larger production work with 26" swing x 51" turning length (660 x 1295 mm).
  • Two M27 x 80" combination lathes for valve and shaft turning up to 27" swing x 80" in length (686 x 2032 mm).
  • Two M27 x 120" (305-mm) combination lathes for longer shafts.

       

Watson Grinding was able to convert its valve turning operations to CNC in short order, and was shipping finished valves in a couple of weeks. Large-diameter parts are machined on the Romi M-Series lathes. The headstock has both a high and low-gear range, and these lathes feature rigid construction, large swing capacity, and the ability to machine tough materials. This dual-range gearbox allows the spindle motor to deliver high torque at low speeds, permitting heavier metal removal without bogging down the machine. The result is faster cycle times on large-diameter, high-alloy components.   

Higher-volume jobs are put on the G-Series slant-bed machines. With 50-hp (37-kW) spindles, these machines are also equipped for heavy-duty turning. The machines are equipped with GE Fanuc 21i controls and programmable tailstocks. A two-speed gearbox is standard on the G50HT.

Omer Cloutier, operations manager, explains: "Previously, making a large pump shaft on our manual lathes would take 20 hr. Now the shaft takes 11 hr on the Romi M27 due to the ability to program all the profiles on the shafts with a single tool. The need for a programmer is eliminated, because the machinist programs the part as he goes."

The Romi M-Series lathe can be operated in both manual and CNC modes. "After a short time, the operator will only use the CNC side of the control," Cloutier says.

Typically, one Romi M Series will replace up to three manual machines. Also, both the M27s and the G50 HTs have exactly the same control and conversational programming system.

       

Custom Tools Lower Cost-Per-Part

When Buck Buchenroth says that what really sets West Ohio Tool Co. (Russells Point, OH) apart is the relationships the company has built with its employees, its customers, and its vendors, you might be tempted to roll your eyes.   

Until you consider that:

  • President Kerry Buchenroth spends most of his time at the customer's spindle, not at West Ohio, and not in the purchasing manager's office.
  • West Ohio specializes in custom drills, reamers, and step tools, and rarely touches end mills.
  • Solutions generally manage to lower both cost-per-part and tool cost.
  • West Ohio doesn't compete on fast delivery or price, which doesn't mean they're slow or expensive, but they work with customers on big improvements, not quick fixes or shaving pennies.

Kerry Buchenroth started machining at Clark Equipment, making big equipment like drag lines and cranes, trying to solve specific manufacturing problems through tool grinding. When Clark shut down, Kerry helped a few other companies with their tool-grinding needs. Kerry joined Honda as a production supervisor in the Marysville, OH, assembly plant in 1983 and was part of the group that started the new engine plant near Anna, OH.

Both tooling and machining fell under him, and he later combined the knowledge he had gained in both disciplines when he moved to Honda Engineering to design and build production lines. Now, he's often supplying tools to run on the same equipment he built for Honda during the 1980s and 1990s.

Kerry started West Ohio Tool Co. in 1989 in the back of his garage. He was still full-time with Honda, but back in production and concentrating on tooling. Oddly, his new tool company found its first niche grinding carbide saw blades and chain saws, but Kerry dreamed of getting a Cincinnati Monoset and grinding metalworking tools. Scouring the used machine and auction listings eventually yielded some opportunities. He and his wife, Kim, found a Monoset in a Pennsylvania backcountry grind shop.   

After doubling the room in the garage, Kerry rebuilt a 28 x 32' (8.5 x 9.8-m) barn and moved his machines there. The Buchenroths still had beef cows on the property, so "we needed a new barn anyway," Kerry chuckles. Kim says the FedEx driver wouldn't deliver their packages—because he was afraid of the horse flies. "He'd stay in the truck and pitch our stuff." But horseflies or not, Kerry's dream was starting to flourish. He had two Monosets and was grinding metalworking tools.

By 1993 he quit Honda, and in 1994 it was clear they needed yet another building, so they ordered a 60 x 80' (18 x 24.4-m) steel barn kit. Kerry and Kim would grind all day and build the barn at night. Their son, Buck, joined the company in August 1996 and the building was finished by Thanksgiving. Daughter Kaci joined the team in January 1998 to take care of the accounting and tax work. By 2000 it was apparent they needed more room and the "barn behind the house" image did not match the quality of their tools, so planning began for their 21,000 ft2 (1951 m2) production facility in an industrial park. West Ohio has been "off the farm" since 2001.

Kerry has an eye for new technology and today the company has a full array of advanced tool grinders and inspection and measuring machines from Walter Grinders Inc. (Fredericksburg, VA). "We've been loyal to Walter," adds Buck, "and I have to say, a lot of the business we've had over the years has been from Walter contacts. That's just part of the relationship."

West Ohio Tool purchased a Walter Helitronic Power CNC tool grinder, which was delivered in January 1997. A second one was acquired in mid-1998 and later that year West Ohio entered the world of PCD tools with an EWAG RS 15 manual machine. By year-end they had their third Helitronic Power CNC machine. A Walter noncontact measuring machine enabled West Ohio to begin certifying their tools with micron-level accuracy and repeatability. In 2002 they became the first company in the US to get a Walter Helitronic Power Diamond, a CNC machine that both grinds and erodes PCD cutting tools.   

These days, Kerry never touches a machine. Instead, he's constantly visiting manufacturing engineers at the spindle, helping them solve machining challenges. West Ohio's goal is not to make the same tool at a lower cost, although they are very efficient at what they do. Instead, they strive to both lower customer tool cost (perhaps by lengthening the duty cycle) and to slash the total cost-perpart by speeding the production rates. This typically means redesigning the tool based on West Ohio's experience with cutting tool geometries and materials, and how they affect the machining of a variety of metals.

Kerry explains: "Sometimes it's just a case of taking two or three tools and combining them into one to save cycle time. Sometimes it's a matter of changing from a straight to a helical, or changing the number of flutes, or changing feeds and speeds. Sometimes it's a case of me bringing a tool back and finding Buck has already been thinking about a redesign, because he sees the regrinds coming through every week."   

Buck is probably among the first in the US to use Walter's new Tool Studio software to vary the helix angle from front to back within a single drill (these days it's more common in endmill design). He explains the process: "With Tool Studio, I created a helical flute on the pilot and a straight flute on the body. So it changes gears right there at the intersection. But it's not for the faint of heart."

One customer wanted to hire a tooling engineer and asked for advice on what to look for. "Turns out they couldn't find anybody like that. So they asked Buck and me if we would be their tooling engineer. So we said 'yeah, we'll help you out.' That's how you build relationships," Kerry says.

Meeting delivery times is another way to maintain those relationships. Every tool moving through West Ohio is bar coded and scanned as it completes the intended operation at each station. It all feeds into a central computer that can track where every job is. About 95–98% of their business is within the 4–6 week delivery window, but they do offer faster service at a premium. Their basic philosophy is to partner with the customer to make tool improvements and then to keep them out of crisis mode. If a crisis does occur, West Ohio maintains an inventory of raw bar stock and can cut and prep blanks in-house.     

       

Presetting Boosts Production

Walking around a shop full of CNC mills, lathes, centerless grinders, a metrology lab, and special metal-treating equipment, it's obvious that engine valves are not a commodity item in the NASCAR, NHRA, and F1 worlds.  

Xceldyne Technologies (Thomasville, NC) is arguably the world leader in high-performance valve train part production, and in the machining of other racing components. It has invested significantly in manufacturing equipment to produce titanium valves for these high-performance applications, producing hundreds of valves per day, every day.

For Nextel Cup engines, valves are changed out after every race, every weekend. Valve-train parts include titanium valve locks, valve seats, retainers, guides, and other ancillary products that support the valve. Other parts produced by Xceldyne are fuel pumps, cam drives, and various prismatic engine and suspension components. They are machined on vertical and horizontal milling centers in a production environment, and by CNC milling in the R&D department.

In the last three years, the plant has expanded to 35,000 ft2 (3252 m2), and all the equipment on the floor is less than four years old. In all, the company is operating 55 CNC machines to accomplish its work, supported by a state-of-the-art metrology lab.

With that kind of demand for its products, Xceldyne sought a way to get more production out of its machining centers. One of the bottlenecks it identified was measuring or touching-off tools on the machining centers to measure offsets. When the machines were doing that, they were not making chips.

Production time was lost, Xceldyne estimated, perhaps as much as 10% of the machine time. Ten percent of a two-shift day could be up to two hr of machine time.

"We went to the IMTS show with the intent of finding ways to improve the efficiencies on the job-shop side of our business," says Eric Gale, milling group leader. At IMTS, Xceldyne visited Zoller Inc. (Ann Arbor, MI) and learned about its smile tool presetter.

A few months later, taking delivery of the Zoller smile, Xceldyne decided to install it right next to the machining center cell where it could support the shop's production milling. Zoller came to the shop to train the crew for several days on-site.

The smile is a universal, noncontact, vision-based presetter and measuring machine that is designed to be quick to learn. It can handle tool diameters to 600 mm and lengths to 800 mm. Measurements are repeatable to ±0.002 mm, with a display accuracy on the 12" (305-mm) TFT color display of 0.001 mm—which is a big help when the crew at Xceldyne is inspecting insert edges for damage and wear.

The smile is provided with Zoller saturn set software, which is designed for the small to midsized shop and can store data on 300 different tools. An intuitive GUI helps the operator through the measuring process. The software provides automatic edge recognition in all four monitor quadrants, and can measure length, diameter, radius, and two angles on each tool.   

In operation, the operator puts the holder in the high-precision spindle and can index it in 90° increments. It's clamped through a membrane keyboard. Zoller provides adapters for all toolholding systems, although Xceldyne uses mostly CAT-taper tooling. A one-hand operating handle lets the operator slide the camera into position to view the tool.

Most of the tools on the machining centers at Xceldyne need to be preset to 0.020–0.030" (0.51–0.76 mm) to start, and some jobs require a 30-tool complement to complete a part. The company soon found that once it set each tool, and each tool was dead-on, much less time was required to set up each job—an additional time savings beyond eliminating the on-machine tool setting.

The presetter is a particular help in setting a boring tool. Previously, the company would adjust a boring tool and touch-off, then make trial cuts, then reset it. According to Gale, "With the Zoller smile, a preset tool will cut within 0.001" [0.03 mm] of the preset dimension," says Gale. "When we need to make a change, the offset is available from the Zoller, and can be downloaded to the machine tool directly and accurately.

"The thing I like about it above the other benefits is that it gives us the ability to make setup sheets off it," Gale states. "You can detail your tools very accurately, include setup notes, and include type of toolholder used and tool lengths. So when we re-run a job, we already have the tooling detail, making setup much quicker. That really helps us keep up with demand for our parts. And we can duplicate the parts every time."

       

Laser Calibration Ensures Tie-Bar Accuracy

Calibration of lathes is crucial for positioning when turning tie bars for the clamping systems of plastic injection-molding machines and die-casting equipment.

"Turning tie bars is no small matter," explains Larry Green, plant engineer, Kelm Acubar (Benton Harbor, MI). "Tie bars can be up to 16" [406 mm] in diam, 20–35 [6–10.6-m] long and weigh as much as 32,000 lb [14,515 kg]. Often, customers specify tie bar tolerances of ±0.002" [0.05 mm] over 100" [2.54 m] or more," says Green.

"Holding precise tolerances is fairly routine now; we haven't had a reject in years," says Green. "Ten years ago, we were making tie bars with buttress grooves for a customer, but there were many discrepancies between what we measured and what our customer measured. Basically, there was no way to position or measure the buttress grooves as accurately as they wanted them. As many as 60 grooves could be specified and at that time we had difficulty measuring to determine if we were meeting the tolerances of 0.002" [0.05 mm] over 65" [1.65 m] on a set of four tie bars. The customer couldn't find anybody else who was doing better, and tried some of our competitors. They were unable to meet the specifications," Green says.

Tie bars, usually a set of four, apply force to the platen. If the clamping system is out of tolerance, the pressure exerted on the tie bars and platen will be unbalanced, and will cause one or more to carry an excessively high load. This situation causes many problems, including bar fracture. There are many tie-bar system designs; one is a multiple buttress-groove system composed of 50–100 (or more) buttress grooves extending sometimes in excess of 100" (2.54 m).

Green had looked at buying a laser-calibration system even before the tie-bar accuracy issue arrived, but its price tag was too high. Instead they opted to pay an outside service to calibrate and compensate the lathe. Yet the calibration and compensation service had no effect on the lathe's ability to hold tolerances.

"We heard about a laser calibration system from Optodyne Inc. [Rancho Dominguez, CA] that cost significantly less than other systems, and decided to see a demonstration," says Green. "The Optodyne rep set up the equipment in about five min. We took a 15-min warm-up break, and four min later the rep said the lathe had been compensated from the wrong side."

Green says that the only question Kelm Acubar had at that point was: "Would compensation from the correct side allow the lathe to hold the tolerances we needed to satisfy our customers?"

Optodyne's laser calibration system requires only two optics, a laser head and a retro reflector, which are mounted on the machine. This makes it easier to align, and therefore much faster to set up than other systems.  

The Optodyne laser meets NIST traceability requirements and features a stability check of better than 0.1 ppm, accuracy of 1.0 ppm, and resolution to 1 µin. (0.00003 mm). Additionally, the system can automatically compensate for environmental factors, including barometric pressure, air temperature, and material temperature, to compensate for thermal expansion.   

Based on Optodyne's patented Laser Doppler Displacement Meter (LDDM) technology, the system works by reflecting a modulated laser beam off a target. The beam is detected and processed for displacement information.

The reading head is sent to the home position, and the operator specifies the measurement increment. When the system is activated, it automatically senses movement, and after an operator-defined interval, data collection is automatically triggered after the table stops. The process continues by stepping through multiple measurements along the full length of the lathe.

The deviations between the scale and the positions measured by the laser are determined, allowing calculation of a compensation table. In some cases, a single linear correction factor is used. In others, a nonlinear incremental correction can be applied.

"We bought the Optodyne system," says Green. "I compensated the lathe and then refined the measurements over a period of time. The lathe became extremely accurate, and our customers could no longer refute our findings. Typically we would send out a set of four bars having a tolerance of ±0.001" [0.03 mm]. Of course, that stretched into other applications, and we calibrated our other CNC and manual machines. Our products got better and better, and we bought a second laser."

According to Green, he checked the two lasers against each other, and they were right on. Still a little doubtful, he thought they needed a NIST traceable standard (National Institute of Standards and Technology); a 10' (3-m) long Invar bar calibrated to ±0.0002" (0.005 mm) seemed to be ideal. He presented the concept to a NIST metroloty engineer who told him that it would cost a half-million dollars to calibrate such a bar, and that nobody in the industry would be maintaining (or even measuring) to the tolerances being achieved by Kelm Acubar.

"We have not had any measurement problems since we started using the Optodyne laser system," says Green. "When we run these programs that do long tie bars and other long bar applications, we put temperature compensation in the programs. The system allows us to input the temperature of the machine and the bar into the program. It puts in a correction to a millionth of an inch. Now, we're working on coming up with a laser function for other applications."       

        

Work Hard And Deliver Quality Tooling

A California shop owner Ron Storf spends most of his waking hours (and some non-waking) in his shop, getting the work out. Storf is a tough guy to catch. He's like a blur in the 4000 ft2 (371-m2) shop that is RSR Tooling & Manufacturing LLC (Santa Ana, CA).       

The five guys who work with him know he's there, but they're just not sure at the moment exactly where. "What this shop has is me!" says Storf, to everyone and to no one in particular, but loudly enough for those not otherwise preoccupied to be reassured who runs things around here.

Storf started as a mechanical engineering student. While a student, he began designing, primarily progressive dies and stamping tools, and started working for his father and a partner who had been designing tooling, primarily aerospace tooling and progressive dies. "By the time I was 17 or 18, I was a pretty decent designer. And then I never stopped— designing, that is. Between my dad's contacts and my contacts and the ones I've made since, I know a tremendous number of people in many different companies and industries. I had a solid customer base when I was ready—prototyping, reverse engineering, tool design, but no production work, thank you. Production just isn't very compatible with precision tooling."

Storf started RSR with a three-axis CNC conversion mill with a control, a manual mill, and a manual lathe. He quickly added a CNC engine lathe to allow CNC turning, and that was enough to start making smaller tooling, and to get things started.   

"My goal at the time was, and still is, not to go into debt to the point where I would have to take work just to pay down debt," Storf says. "I had enough work to completely fill my capacity and beyond, so what I've been doing ever since the early days has been buying equipment and hiring help to increase my capacity and growth. My problem isn't getting work; my problem is being able to do more work."

RSR's mix of work is about 60% aerospace tooling, a lot of assembly weld fixtures, and production tooling for line work "The balance is a little of this and little of that," Storf says. For example, RSR does supercharger brackets for a company that builds aftermarket supercharger kits for Chrysler Hemi automobiles. He does a lot of prototyping for various engineering consulting companies, which involves a lot of time collaborating on design, followed by frantic work to make one to five intricate components.

"When I was in the market for a vertical machine, perhaps a lease trade-in, something along those lines, a friend mentioned GBI Cincinnati Inc. (Cincinnati) and Kevin Bevan, the company president. GBI was bringing in the line of Feeler VMCs, HMCs, turning centers and boring mills. At any rate, GBI was looking for people who might be interested in being early adopters, to get machines out in the field and seed the ground for future growth. Nothing uncommon about that; all the builders and distributors do that. So the result was GBI and Bevan were pretty accommodating. Basically we got a Feeler for quite a good price; plus, it allowed us to get a relatively larger machine than we'd planned."

What Storf bought was a Feeler FV-1600, a 40-taper, 20-hp (14.9-kW), 8000-rpm VMC with 63 x 32 x 32" (1600 x 812 x 812-mm) travel (X, Y, Z) with linear-guide ways. Table size is 66 x 32" (1676 x 812 mm) with a 2200-lb (998-kg) load capacity. Rapids: 708 ipm (18 m/min) (X, Y) and 590 ipm (15 m/min) (Z); positioning accuracy of ±0.0004" (0.01 mm) and repeatability of ±0.00012" (0.003 mm). The 22-tool carousel has a tool-to-tool change of 7 sec.

"When you're doing tooling work," Storf says, "it's better to have a larger rather than a smaller machine. It's a rare occurrence when I do more than ten of something; most of what I do is one of a kind. A larger work envelope has more possibilities to do a different variety of jobs. Sometimes the parts are long; sometimes they're multiple setups; and sometimes the added Z height is most useful. It allows us to work a much larger part than we otherwise would be able to do.

In his shop Storf has vertical milling, manual milling, multiple CNC turning, manual turning, cylindrical grinding, and surface grinding. "You name it," Storf says, "You have to be able to do a little bit of everything in-house. The only thing I don't have now, and I'm planning to buy before the end of the year, is wire EDM. Again, it's primarily for my convenience, just so I don't have to send the work out. It likely will sit idle 90% of the time, but that's fine. The 10% of the time I do need it, I'll not be dependent on another shop's scheduling, which is a killer in the kind of work I do."

RSR machines all the more common aluminum alloys, 6061 and 2024, 7075 aluminum, and A2 and D2 tool steels, CPM metals, some titanium, nickel-based alloys, 4130, 4340, and stainless. "We're a tool shop," Storf says, "we run everything. And the Feeler's up to it. My big things are reliability and versatility. I need an accurate machine that will be reliable long-term, and that's what I've gotten so far from the Feeler FV-1600, Chinese or not."

A lot of the success with any machine, Storf says, is in the programming and the tooling. "I don't program the Feeler the same way I would a 50-taper machine with box ways," he says. "The Feeler has linear ways, and I'm familiar with the position some people argue—they knock linear guide way machines as lighter-duty and somehow inadequate. But I consider the Feeler to be a medium-duty machine with a lot of iron in it. It's got good vibration dampening, and I have no issues with it. I do tool steels all the time, and I do a bit of hard milling, also, and the Feeler takes them on without so much as a shiver."

With the larger work envelope, the Feeler has allowed Storf to take on other work. "Like I mentioned earlier, my problem isn't finding work. I provide tools that work. There's a lot of value added in what I do. I provide a service, working tools with pretty ridiculous tolerances like 0.0005" [0.013-mm] true position between multiple features on various planes on a relatively large tool. It's not easy, but the Feeler allows me to build that kind of tool, over and over again."

 

This article was first published in the September 2007 edition of Manufacturing Engineering magazine. 


Published Date : 9/1/2007

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