Shop Solutions: Fluid System Boosts Shop Productivity
Capital Engineering & Mfg. Co., a family-owned company located in Chicago, started 50 years ago as a military parts supplier. Today, the company has expanded to a 300,000 ft2 (27,900 m2) shop. About 100 employees produce fabricated and machined metal parts for customers in the off-road equipment, compressor, railroad, and defense industries.
Hoping to lower fluid costs and boost tool life, Capital Engineering recently decided to try a new metalworking fluid system.
The patent-pending Tri-Logic fluid system from ITW Rocol North America (Glenview, IL) treats all aspects of lubrication of the machining process as one interdependent system. The system consists of three products, which work together to prolong fluid and tool life and improve workpiece surface finishes.
For example, one of the main causes of coolant odor is contamination by tramp oils. The Tri-Logic system's slideway oil is formulated not only to resist microbial attack but to actively reinforce the antimicrobial properties of the cutting fluid.
While in the lubrication system of the machine, the oil performs as a typical slideway lubricant. However, when the product enters the cutting fluid emulsion, antimicrobial additives help eliminate destructive bacteria and fungi.
The slideway oil works with a range of specially formulated cutting fluids: Tri-Logic ML (maximum-life, general-purpose fluid); Tri-Logic EP (heavy-duty cutting fluid) and Tri-Logic AL for aluminum alloys. All three fluids offer maximum microbial resistance for a wide range of materials and machining processes.
Finally, Tri-Logic RTD is a tapping fluid suitable for some applications that reduces the availability of nutrients for bacteria and fungi and is fully emulsifiable. Rather than causing contamination problems, it mixes into the cutting fluid, and high-performance additives in the tapping fluid then improve the performance of the cutting fluid.
Capital Engineering chose Tri-Logic EP cutting fluid. It is currently running at a concentration ratio of 20:1. "Tri-Logic has been in the sump for nine months now. Before, we used a synthetic that we had to change every six months," says VP of Manufacturing Borys Jarymowycz.
Some machines with full sumps are unused for up to two weeks between jobs. According to Jarymowycz, use of the fluid system has eliminated "Monday morning odor" and coolant residue buildup in those sumps. "And, no one complains anymore about skin irritation. It was a big problem before," he adds.
Jarymowycz reports that the fluid system has also had the desired effect on metalworking productivity. "For one stainless steel job, tool life has doubled while cutting speed increased up to 400%," he says.
Racing Into Five-Axis Machining
CAM software proved critical to helping a British motorcycle racing team move successfully into five-axis machining, a change that has brought huge benefits on the track and off.
Owned and managed by motorcycle legend and triple World Championship winning rider Kenny Roberts, the Proton KR racing team has brought more of its machining work in-house, giving designers more freedom. Most of the components for the bike's frame also are machined from solid instead of being fabricated.
Proton KR is the only independent team that ran in the 2004 motorcycle Grand Prix racing season. Unlike factory-sponsored teams, Proton develops and builds its own racing designs at a manufacturing facility outside Banbury, England.
Programmer and machine operator Andy Stokes says it took a little time to take full advantage of the company's new DMG DMU 50 eVolution five-axis machining center. "With five-axis machining, you have to look at the job a bit differently," he explains. "You need to adjust your approach to fixturing and workholding to access the maximum number of features in each setup. But once you're used to it, five-axis machining makes things easier, even for parts that could be made with our three-axis machine."
The transition to five-axis was facilitated by Proton KR's choice of CAM system, PowerMill from Delcam plc (Birmingham, England). Stokes says the combination of CAM, wire EDM, and five-axis machining has enabled Proton to fabricate motorcycle frame components from solid. "Manufacturing from solid gives better structural integrity at lower weight than the equivalent fabricated parts," Stokes explains. "With our new methods, we have reduced the weight of the bike by more than 15 kg."
"In addition, the machined components are much more consistent," he says. "Previously, we always had to grind new parts to make them fit. Now, we can take spares off the shelf and know they fit straight onto the bike."
The combination of PowerMill and five-axis machining has also been used for R&D work on the team's new 990-cm3, V-5 engine. "We have machined many different port designs to try and obtain the optimum engine performance," Stokes says. "PowerMill has the flexibility needed for this work. It has done everything I've asked it to."
Another area where continuous five-axis machining has proved useful is in the manufacture of tooling for carbon-fiber composite parts and in trimming the composite components.
Stokes predicts even better results from the DMG machine in the future. "The designers now realize what it can do, so they're changing the way they think," he explains. "With the three-axis machine, I often had to ask for designs to be simplified to make them manufacturable. Now, I can normally manufacture anything the designers ask for"
Versatile Tools Speed Turning
Established in 1999 by Josef and Susan Kaltenegger, their two sons Hans and Jeff, and son-in-law Nico Morowat, Kaltech Mfg. (Delta, British Columbia) specializes in white-iron machining and other tough, quick-turnaround jobs for local pulp-and-paper industries and other applications.
One of the shop's most difficult jobs involves threading of large bolts used to secure heavy cables on hydroelectric dams. The operation requires removal of a lot of material to produce the 460 X 14-mm trapezoidal threads.
For turning, the shop was searching for a tool that could handle roughing of the entire workpiece, then finishing the thread root. "We were ordering an insert from Sweden, and it just wasn't convenient or cost-effective," operations manager Hans Kaltenegger recalls. "We didn't think there were any inserts in North America that could do the job."
Then a tooling rep introduced Kaltech to the A4 groove and turn tooling system from Kennametal Inc. (Latrobe, PA). Designed for high productivity on machines with limited tool positions, the system is rigid enough to provide stable cutting even with high machining pressures and relatively long overhangs. Secure clamping and bottom-V seating of the insert enable higher feed rates and depths-of-cut.
Although the A4 system was engineered for turn, face, profile, OD and ID groove, bore, and cutoff applications, Kaltech uses it in 95% of its production of large external square threads. Used for primary roughing, the system cuts finishing time by removing the bulk of the material before finish passes are made with a threading insert. "The tooling enables our machinists to precut the coarse thread on very large bolts," Hans Kaltenegger says.
According to Kaltenegger, Kaltech was able to push the tool to accommodate a thread feed rate of 50 ipm (1.3 m/min) at 88 rpm. Machinists are now threading eight pieces per A4 edge, helping to reduce production time by 70%.
"The bolts are machined from large amounts of material, and we often have a lot of overhang, which usually causes chatter," Kaltenegger explains. "The tools minimize chatter and leave a very good finish."
Used to machine 50 bolts, A4 tooling saved Kaltech roughly 25% in costs. Kaltech saved approximately 20% per part in labor costs and approximately $300 per part in insert costs. Hans Kaltenegger estimates a competitor's tool would have taken five inserts per part to complete the job.
Grinding Supports Gage Precision
Manufacturers worldwide depend on pin gages from Meyer Gage Inc. (S. Windsor, CT) to verify the quality of their parts. To maintain its competitive edge, Meyer has recently transitioned from labor-intensive production to more automated processes. The update includes two centerless grinders, which are used for finishing operations on standard gage pins in diameters from 0.061 to 1.020"(1.55 - 25.9-mm) diam in 0.1" (2.54-mm) increments.
Pin gages are precision metal plugs used to determine the acceptability of diameters and depths of drilled or machined holes, for checking hole location and distance, and as masters to calibrate measuring equipment. Because they are used as standards, the gages must be manufactured to exacting tolerances. Depending upon the class, gage pins may have a tolerance of from 0.0002" (5 µm) to as tight as 0.00004" (1 µm).
Considering the different pin tolerance classes, English and metric dimensions, and various pin combinations, Meyer offers some 90 different pin gage sets consisting of hundreds of part numbers. It can take weeks to manufacture all of the part numbers in a given set, so batches of up to 20,000 pieces of an individual pins are processed at a time.
All the pins are manufactured using a through-feed centerless grinding operation. The parts start as a long 52100 alloy steel bar that is cut into 2" (51-mm) lengths. After deburring and heat treating, pins are rough ground to bring them closer to size. Finish grinding takes place on one of two RK model 220-8 centerless grinders from Cincinnati Landis (Waynesboro, PA).
The finishing operation removes a maximum of 0.001" (0.025 mm) of material. After surface grinding to smooth the pin ends, each pin is etched with size and serial number identification.
The centerless grinders have 20-hp (15-kW) main drive motors and are fitted with aluminum oxide grinding wheels. The machines use cam-type antifriction profile truing with a servomotor diamond axis.
"The ability of the RK centerless grinders to consistently hold roundness on these parts is a real benefit to us," says VP James Meyer. "That enables us to take a 0.0002" tolerance Class ZZ gage pin and work the part down in a lapping machine to produce more precision parts such as Class X or XX pins."
Productivity at Meyer Gage has also improved. Each RK centerless grinder replaced two or three older non-CNC machines. Fewer through-feed passes are now required, stock removal is better, and geometry is improved with reduced wheel dressing frequency.
According to Meyer engineers, the machines' fixed grinding wheel position improves rigidity and speeds setups. An upper/lower slide arrangement under the regulating wheel and workrest requires only a single adjustment for rapid, accurate correction of taper or wheel contact.
EDMs Spark Silicon Valley Success
Ron Witherspoon Inc. (RWI) is located in the Silicon Valley, probably the most competitive high-tech manufacturing region of the US. Founded more than 25 years ago, the company employs over 120 people and operates from two locations. The 18,000 ft2 (1675 m2) Campbell facility houses RWI's Engineering and Prototype Division; Castroville is home to the company's 87,000 ft2 (8100 m2) Production Division.
RWI specializes primarily in the fabrication of high-precision, intricate components for the medical industry. The company is a large producer of components for collimators, which filter radiation beams used in cancer treatment and other medical applications.
Much of the work is done using electrical discharge machining, and the department is anchored by machines supplied by Mitsubishi EDM (Wood Dale, IL). EDM equipment includes four Mitsubishi FA-10P wire EDMs, which cut collimator components around the clock, according to EDM department manager Brian Pagano. The department also employs sinker machines from Mitsubishi.
A true test of the machines' capabilities came when another customer approached RWI with a very specific request. "We were asked to produce a 3" [76-mm] tall triangular-shaped carbide mandrel with straightness and form tolerances of 0.0001" [2.5 µm] or better," Pagano recalls. A Mitsubishi machine produced a prototype with the finish, speed, and accuracy required by the customer.
After a short production run of the part, design specifications changed. The new design required the same tolerances to be held for a 3" tall round carbide mandrel 0.063" (1.6 mm) in diameter. Part prototype and production were completed on a Mitsubishi VA-10P sinker EDM with small-hole option and SP circuit.
"With an eager customer and long-term production opportunity, we purchased a second VA-10P, fully loaded with options," Pagano explains. "The speed and accuracy cut production time in half." The two Mitsubishi sinkers are housed in a separate, temperature-controlled room.
RWI has a very aggressive capital equipment turnover program, upgrading its machines every few years to keep pace with advancements in EDM technology. The company is currently producing experimental microwave and RF devices, which will be coupled with imaging devices and applied to homeland security equipment in the future.
The US government grant program is a new frontier for a machine shop, according to Pagano. "Previously, machine tools weren't considered capable of producing the required micron-level precision that they now can," he says.
Pagano says such EDM features as corner control, fast auto-threading, and table isolation allow the machines to hold micron-level dimensional tolerances and very fine workpiece surface finishes. RWI can micro-EDM holes as small as 0.001" (0.025 mm) in diameter. The company's conventional high-speed machining centers, with spindle speeds up to 30,000 rpm, allow the company to meet fast turnaround requirements. According to Pagano, RWI's strategy of investing in high-tech, high-quality equipment and turning it over quickly gives the company a consistent advantage over the competition.
This article was first published in the February 2005 edition of Manufacturing Engineering magazine.