Grinding shop steps up to CNC machining

Rob Murnyack had been turning his professional life upside down in a quest to use CNC machining at his shop. He'd been working for his father for more than 20 years in what had become a successful grinding operation. However, Mr. Murnyack wanted to take the company to the next level--using CNC machining.

"We couldn't gather a powerful enough argument to nudge my father over the line," Mr. Murnyack says. "I can't blame him. He's 65 and has built a solid business around manual operations, and for him to invest $150,000 to $200,000 to move in a new direction was a tough sell."

Mr. Murnyack worked out a deal with his father, setting up a kind of "beta site" operation. He took several of his father's employees, a number of established customers and four manual grinding machines and began Absolute Grinding (Mentor, Ohio) in May 1994. Then, 4 months later, he found himself in Chicago, Illinois at the International Manufacturing Technology Show (IMTS).

"I wasn't making a salary at this point," he says. "Here I was looking at machines that cost $200,000 and more. I thought I was nuts. But at the same time, I realized I needed to make the investment if I wanted to shift gears to CNC."
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Obviously, a lot rode on his first plunge into CNC machining. He chose a Studer S35cnc universal cylindrical grinding machine from United Grinding Technologies (Miamisburg, Ohio). It had a choice of a straight or angular infeed with the grinding wheel mounted left or right; wheel dressing and profiling with continuous path control; automatic grinding and dressing cycles; automatic change-over from external to internal grinding; and an automatic swiveling wheelhead. It also allows the use of up to three grinding wheels in a single workpiece program, as well as a special workhead with a C axis that permits form and thread grinding.

Mr. Murnyack notes that none of his employees were familiar with CNC, so in that respect, the new machine had to be easy to learn. "We literally self-taught ourselves," he says. "The programming was that easy."

Three years after he entered the CNC arena, Mr. Murnyack added an S36cnc, a universal cylindrical grinding machine for medium-sized workpieces. His objective was to find a quality machine that could do internal and external grinding for less than $250,000.

One of the bonuses of the grinding machine, according to Mr. Murnyack, was that it allowed the company to do random wheel shapes and more intricate configurations of the grinding wheel and of the grinding cycle. In general, it gave Absolute the ability to tackle complicated projects.

The latest addition to the company's fleet of Studers is the S31 cnc purchased in 2001. Mr. Murnyack thought he should investigate the new generation of CNC machines, which are more flexible than their predecessors and would allow the company to handle a wider variety of parts with a reduction in setup time. The S31 took care of this, with a drive-spindle power of 10 hp, grinding wheels with a maximum diameter of 20 inches, a width of 3.15 inches and an infinite B axis. It permits grinding ID, OD and tapered ID's on one machine.

"We do four or five setups a day," he explains. "This is a job shop. We can't spend 4 hours on a setup. My guys can switch from an ID operation to an OD operation on a different part in an hour with the S31. With other machines, I hear from people in the field that they might spend 4 hours just writing the program. It takes us just 5 minutes to write these programs on the CNC machines."

Because of the significant time savings the company has discovered when using CNC machines, Mr. Murnyack and his shop employees understand what a difference they can make in a shop's efficiency. Not only are these machines easy to operate, but they also provide quality machining to complicated projects. They also allow one machine to perform many tasks, rather than wasting time using several machines.

Orscheln's Screw Machine Division Installs Two New CNC Lathes

Orscheln's Screw Machine Division (formerly known as Qualico Precision Products), Moberly, Missouri has recently installed two new CNC lathes.

This Orscheln location offers screw machine products, plating and coatings and is a QS9000 registered company.

The two new lathes, EmcoTurn 420MC plus models, feature two spindles with two sub-spindles and auto bar-feeders.

"These lathes represent the newest technology available," stated Orscheln's Plant Superintendent Daryl Duchesne. "They will replace several manual screw machines as well as secondary equipment since they produce finished parts. This will improve our efficiency and help lower our costs, especially on machining-intensive parts."

The company has 35 other screw machines (single and multispindle) and various secondary equipment. It specializes in high volume, long run, precision screw machine components, but is capable of low volume orders as well.

The screw machine operation works with steel, brass, aluminum, copper, stainless steel and plastics up to 1.25" diameter in round, hex, tube and square stock.
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Over 20 variations of plating are offered at Orscheln. Its plating lines utilize barrels 36" in length and 16" in diameter.

Coatings offered include dipspin Magni-Coating, Elisha's EMC (Electrolitic Mineral Coat) process and powder coating.

The company serves a diverse range of customers in such industries as: automotive, off-highway, furniture, computer, marine, aircraft, military, lawn & garden, heavy truck, recreation, construction and agriculture.

Efficient CNC flexible system transfer saves time and money

Since its organization in 1994, American Axle & Manufacturing (AAM) (Detroit, Michigan) has been proving to the industry that a U.S. manufacturer can be competitive on cost and quality. The company attributes its success to its investment in manufacturing technology and training.

To meet quality and volume requirements from a customer who hoped to increase the torque and load-bearing capabilities of its full-size pickup trucks and SUVs, AAM engineers developed a process to produce a new rear differential gear carrier. It was the largest the company had ever produced, at 118 pounds.

The process initially used a series of large horizontal machining centers (HMCs) to meet the demand for the 11.5-inch carrier. Then, using the same process, fixtures and tooling, AAM ramped up using a CNC Flexible System Transfer (FST) line from Heller Machine Tools (Troy, Michigan) when volumes went from 35,000 to 240,000 parts annually. The process and the equipment permitted the plant to respond quickly and cost-effectively to the change in demand while consistently achieving quality goals.

In developing the carrier design, AAM paid special attention to details that would positively affect the part's perceived noise, vibration or harshness characteristics, and would thereby provide an advantage to customers in the pickup truck and SUV market.
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Once the parts were designed, the company conducted simultaneous engineering programs with three machine tool companies to evaluate each vendor's approach to its manufacturing challenge. In each case, AAM was interested in flexible manufacturing cells to handle relatively low initial production volumes. The company also looked for machine tool vendors that used Hirth couplings on their rotary tables, which AAM felt would help it meet critical tolerances. The purpose was to prove that the critical dimensions could be consistent on a machining center.

Carrier housings and differential case housings are two important axle components, which AAM machines and supplies to its customers. These parts have been produced by a number of different machining processes: for example, carrier housings were machined on single-spindle horizontal machining centers and dedicated transfer lines, as well as CNC lilt-and-carry transfer lines. The differential case housing was produced on single-spindle HMCs and lathes.

Rather than using 11 to 12 HMCs to produce the housings, AAM invested in a single Heller EST. In the experience of its Three Rivers facility, the FST has proven to be a reliable high production system and to be more cost-effective than HMCs. According to AAM, the FST has the benefits of using less floor space (in this case, about 30 percent less) and has capital costs of up to 25 percent less than conventional transfer lines.

The facility uses the 14-station FST to machine the 11.5-inch carrier housings. These operations include face milling, drilling pan holes, and machining pads for end-cap seating and rough-boring the axle tube bores. The FST then completes the boring process, maintaining the perpendicularity of bores in the carrier. Each bore is completed in three passes. Once the part is finished, it is unloaded and put on a conveyor to a robot-loaded machining center cell, where the remaining holes are drilled and tapped in the carriers. Empty fixtures in the FST are returned via an overhead conveyor to a washer and then back to the load station.

Six Heller MCP-H250 HMCs are also incorporated at Three Rivers. All the machines have HSK 100 spindles, making it possible to use the same tooling in both types of machines when necessary. A hydraulic workholding system uses swivel pads and locator points on the casting to ensure repeatable clamping. The HMCs are also capable of being retooled and refixtured for other components or to supplement production of the FST.

The FST concept uses predesigned modular units mounted on standardized bases with independently controlled stations. Three basic pre-engineered machine sizes cover component dimension, power and technology applications. System components can be combined to create the system best suited to the application. Because all interfaces between the units are standardized, engineering time is reduced and assembly is accomplished quickly, the company says.

The FST was fully assembled and run off on the Heller assembly floor in Troy prior to the delivery to the company. This allowed the FST to be fully operational and on the plant floor in a third less time than a transfer line usually demands.

CNC grinding machine

The company has released its OpenCNC grinder for CNC ID, OD and centerless grinders. The grinder consists of hardware, software and documentation and has been engineered to meet the needs of machine builders, integrators, end-users and retrofitters who specialize in CNC grinding machines, the company says.

The grinder maintains the flexibility and power of open architecture, while providing ease of use and built-in features of a standard package, the company says. It is said to allow machine builders and end-users to easily upgrade or interchange machine hardware, software and peripheral components without having to re-engineer their existing machine logic.

The part programming features include: 11 wheel dressing routines, eight grinding sequences, advanced grinding wheel offset tools and an online help system. Each part program can contain as many as 20 grinding sequences.

The hardware/software package comes with wiring diagrams, documentation and pro-written PLC logic that allows machine builders or integrators to complete a control retrofit without having to spend weeks writing and debugging special machine logic, the company says.

CNC features important for lathes used on oil valves

Kimray, Inc. (Oklahoma City, Oklahoma), a manufacturer of control valves and related equipment for oil-and gas-producing companies, reports a 40 to 50 percent increase in its machining efficiency, achieved largely as the result of CNC-based production equipment. Control features that simplify programming and setup on the company's latest CNC lathes contribute to this productivity trend.

Founded in 1948, Kimray operates a 125,000 square-foot facility and employs more than 250 people to serve its expanding customer base. The company machines iron, steel, aluminum and thermoplastic materials to build its line of control valves, thermostats, energy-exchange glycol pumps, gas-operated pilots and other control devices. Its products are used to control vessel and lead line temperatures, the liquid level inside pressurized vessels, pressure drops and liquid/gas flow.

The company maintains a turnkey manufacturing facility that includes dozens of lathes, grinders, turning, milling, sawing and bore finishing honing machine tools, almost all with CNC systems on board. The newest arrivals are Emco Maier Emcoturn 420 MC Pills and Hyperturn 665 MC Plus lathes, each equipped with Sinumerik 840D CNCs and Simodrive 611D drive packages from Siemens (Elk Grove Village, Illinois). Kimray operates a host system for file storage and backup on all part production data.
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The company has been especially pleased with the CNCs. One operator explains that with the Sinumerik 840D, programming and cut and paste operations are possible even while the machine is running.

"Each screen allows you to be very detailed about what you're doing, such as separating your mains from your subs with your part and workpiece programs,' he says. "I use the Siemens CNC for axis and spindle movements on both machines. My programs and data can be accessed easily and transferred back to the machines [from the company's main host system] as needed."

He can run operations, such as milling and stenciling, out of the sub programs, he adds. "I use the parts program as my way to transfer files and folders to the main system and back again."

He commented further on the controls. "On a typical setup, I like the sensitivity. Being able to move the axis only a ten thousandth at a time to a hundred thousandth at a time comes in bandy. I also like the program test feature, especially on new programs. Each tool has its own geometry page and up to four offsets, making things less complicated."

Kimray typically machines barstock of 303, 304, 310, 316 and 17-4 stainless steel, as well as D-2 tool steel, 6061-T6 aluminum, brass and Teflon. Cast iron, ductile, steel, stainless steel and aluminum are also machined by the company.

The 665 Hyperturn machine enables four-axis machining plus full C-axis capability on both the main and counter spindles. The 665 uses some of the same programming features, plus the same digital drive systems as the 420, but in a larger package.