Shop Solutions: Best Defense is Advanced Manufacturing
To a soldier on night patrol, a police officer with weapon drawn facing danger, or a firefighter entering a burning chemical plant, having the most reliable equipment may spell the difference between life and death.
In the lobby of Wilcox Industries Corp.'s (Newington, NH) facility, visitors can see wall-length murals of soldiers or law enforcement personnel with the company's products in use in the most difficult and potentially life-threatening situations.
Wilcox manufactures weapon laser designators, weapon optic mounts, trajectory sights, friend/foe systems, hybrid life-support systems, and custom products for the US military and state and local law-enforcement agencies.
The high-quality electronic targeting devices Wilcox Industries supplies for firearms are so cutting-edge that following Sept. 11, 2001, CEO James W. Teetzel decided to stop selling certain Wilcox products on the open market where they could end up in the wrong hands.
The Power Grip Multi-Aiming Device (MAD) is one of those products, available only to military or law-enforcement agencies. The Power Grip is a vertical forend grip for a combat rifle that combines a visible laser system, a Surefire Xenon flashlight, and an infrared illuminator with internal electronics that allow the operator to choose among the three modes.
Wilcox manufactures the majority of the components for its highly specialized, low-volume products. One hybrid life-support system, for example, a scuba-like breathing apparatus for working in hazardous breathing environments, can have as many as 90 different fittings.
Teetzel, who began his manufacturing career in 1982 starting and running a job shop, describes his company as "very diversified within a very specialized niche. I was 22 years old, specializing in aerospace and medical parts," he says. The company was known as UITC Aerospace, which stood for United Industrial Technologies Corp.
By the early 1990s, Teetzel faced two pressing concerns: his main customer was demanding mandatory cost reductions, while at the same time his bank was being taken over by the Federal Deposit Insurance Corporation.
"We needed to diversify," he says succinctly. A shooting sports enthusiast, Teetzel had purchased what he called an inferior laser sight for one of his handguns, and determined he could produce a better one. His subsequent design for an integrated laser sight for a handgun was featured on the cover of Guns & Ammo magazine. The US Navy saw the article, and, in Teetzel's words, "one thing led to another."
By 1993, Teetzel was operating two companies: UITC Aerospace and UITC Armaments. By 1997, he decided to pursue the armaments components business full time, and Wilcox (the W in James W. Teetzel) Industries was born.
Staying on top of production and deliveries is critical for the growing company. "Every manufacturer has a different problem, mine is capacity," Teetzel says. "Resolving capacity problems isn't simply a question of manufacturing methodology, it affects every aspect of our business."
With an engineering education and a machine-shop background, Teetzel keeps a close eye on developments in machine-tool and processing technology. He first began purchasing machines from Mazak Corp. (Florence, KY) in 1982. Although he explored combining processes with a mill-turn machine in 1988, he initially shied away from multitasking machines like Mazak's Integrex as being too complicated to set up for small runs.
As Mazak steadily added improvements, including more powerful and compact motors, higher indexing and positioning accuracy, and increased production flexibility with a lower turret, the Integrex became a high-variety workpiece production machine.
Wilcox now runs two Integrexes: the Integrex 100-III and Integrex 200-IIIS, both equipped with quick-load bar feeders for untended operation. The Integrex 100-III has a 6" (152.4-mm) chuck, 2" (50.8-mm) bar capacity, and parts catcher. The Integrex 200-III is sized for 2.5" (63.5-mm) bar capacity with two 8" (203.2-mm) chucks for the first and second spindles. Both Integrex models are equipped with 40-tool magazines and a 12,000-rpm milling spindle.
Interested in production flexibility, Teetzel was aware of the success another New England-area manufacturer, Little Enterprises (Ipswich, MA), had realized with Mazak's Palletech Manufacturing Cells. Little uses Mazak HMCs together with the Palletech automated system for prototype and volume runs for the semiconductor business. Little maximizes spindle uptime on each of its HMCs by setting up parts on offline pallets on the Palletech system for untended production.
"What really made me go in this direction was Scott Little and his experience at Little Enterprises," Teetzel says. "Many people would initially look at Palletech systems and consider them expensive and complicated. But in reality, with a Palletech you're buying real estate. With a twotier pallet system, we've saved more than 500 hours of setup time, and we can shelve, archive, and retrieve jobs virtually automatically."
Now Teetzel runs not one but two Palletech systems, with a third on order. One consists of two Mazak PFH-4800 HMCs integrated with a two-level pallet-stocking system with 52 pallets and two load/unload stations. The second consists of three PFH-4800 HMCs with a 72-pallet, two-level Palletech system with two load/unload stations.
"We have complete kits on the Palletech systems," Teetzel says. "Conventional machine shops like we used to be have to constantly amortize setup costs. With our Palletechs, when you've paid for an initial setup, it no longer becomes price-sensitive. In addition, our Palletech systems give us inventory contingency, so we can remove setup and inventory considerations from our equations. We gain a tremendous amount of flexibility."
Wilcox manufactures parts for its Power Grip MAD (multi-aiming device) on the Mazak PFH-4800 HMC in the Palletech system. Dan Desrosiers, Wilcox vice presidentmanufacturing, describes the manufacturing process for a particular chassis part that begins with a first operation in which stock is cut and 12 pieces are loaded on each tombstone.
"We then rough-mill the top and length, and rough-contour the pin slot and pockets. To finish the operation, we drill, countersink, and tap four holes. In a second operation, 12 pieces are loaded on each tombstone. We then rough-mill weight-reduction pockets, and drill, countersink, and tap three holes," Desrosiers says.
Process time for these operations totals 26 min per part on the PFH 4800 HMC. "This process saves us 24 min per piece (or 4 hr and 48 min per tombstone), and all parts are retrievable from the Palletech," Desrosiers says. "A further savings of 5.5 hr is achieved per run after the second lot run because machine setup is no longer required. In addition, this process has allowed us to add an unmanned third shift to our operation, enabling us to increase overall manufacturing capacity by 50%."
People are another factor. "Setup people are key to a machine-shop's success, but hard to come by," says Teetzel. "We want to maximize the skills of the people we have. By virtue of having jobs set up in advance, we maximize our people's time and talents and service the customer more efficiently."
Wilcox Industries completes part production with Mazak Nexus VMCs and Nexus Quick Turn CNC turning centers. Teetzel sees Mazak as a close partner not only in his company's growth, but also in growing a culture of world-class manufacturing. By design, Wilcox Industries is continually moving forward in production innovation. "After all," Teetzel says with a smile, "where would I be had I put everything in Warner & Swasey?"
Ford Solves Crankshaft-Drilling Bottleneck
Few things stall a high-volume CNC automotive operation like premature drill failure.
Even when the probe identifies a broken drill right away, the unscheduled shutdown reduces throughput, requires extra labor, and runs up tooling expenditures. Worse yet, when the failure is just chipping of the tool's edge, which the probe misses, scrap and rework rates can run up as well.
Ford Motor Co. machines 220,000 crankshafts a year at its Essex Engine Plant (Windsor, ON, Canada). The plant makes the 5.4- L Triton engine that goes into Ford SUVs, F-series trucks, and other large vehicles.
Drilling, which originally represented just three of 15 CNC operations on the crankshafts, accounted for the majority of the stoppages. Most of the drills didn't even make it to reconditioning time. Ford process engineers figured that the premature failure rates with solid-carbide drills was just plain unacceptable.
The most severe problem was in drilling balancing holes, largely because of an unavoidably unstable workholding setup. The crankshafts are suspended between centers, so they can be spun, much as in wheel balancing. In crankshaft balancing, though, lightening holes are drilled into the heavy side rather than weights being added to the light side.
Ford runs two identical balancing machines. Each first rough-drills one to four balancing holes depending on the out-of-balance condition and follows with shallower finishing passes at the same feed rate.
"Tool breakage was out of control," says Glen Margerison of Ingersoll Cutting Tools (Rockford, IL) who assisted Ford process engineers in solving the problem. "They couldn't keep drills in the machine," says Margerison. "A drill snapped at least once every shift. No solid-carbide drill lasted long enough to be sent out for reconditioning." The resulting downtime for changes reduced throughput to an unacceptable level.
The inherent instability of the unsupported setup let vibration creep in, which can be deadly to brittle solidcarbide drills. A few indexable-type drills with tougher alloy steel bodies that could better handle the vibration were tried. This worked to a point. Tool life improved with the switch to one type of indexable drill, but only incrementally. So the search for a better solution continued.
Margerison recommended Ingersoll's Qwik-Twist replaceable-point drill as a drop-in replacement. The impact was immediate. Drill life improved from 1000 to 7000 hits/tip for rough balancing and from 6000 to 15,000 for finish balancing.
On that basis, Ford engineers standardized on the Qwik-Twist drill and realized annual savings in the mid-six figures. The move saved substantially in both tool costs and downtime. Over both balancing machines, the reduction in downtime translated to production of an additional 415 crankshafts/year.
Qwik-Twist drill edges didn't chip under the same conditions that caused both solid-carbide drills and other indexable drills to fail. Ford could depend on the tool to last through to its entire scheduled service interval. Unscheduled shutdowns caused by drill failure simply went away.
The Qwik-Twist drill's performance results from the design of the carbide tip, and the repeatability to datum from tip to tip. Axial repeatability is within 0.002" (0.05 mm), eliminating the need for touch-off or re-zeroing with each tip change.
Based on success in the rebalancing operation, Ford engineers and Ingersoll teamed up to improve another drilling operation earlier in the crankshaft-production cycle. That earlier process involved 13 drilling, boring, and tapping operations in all. The parts are done two-up on three identical Grob BZ 600 single-spindle CNC machines. Together they convert 300 steel forgings into finished crankshafts every shift.
The bottleneck drilling operation in this sequence was to open a post end hole in three steps:
- Drill a 14.75 x 22-mm diam counterbore and pilot for the tap hole,
- Drill a 60° chamfer, and
- Drill a 10.50-mm diam tap hole 27-mm deep.
All three operations suffered from premature failure of the solid-carbide drills, though not as severely as in the balancing operation. None of the holes was especially deep, and the setup was much more stable than for balancing. Nevertheless, the solidcarbide drills lasted only 500 hits for the pilot holes and just 1000 for the tap holes.
Although these applications were milder than balancing-hole drilling, the switch to the Qwik-Twist drill produced a much larger dollar saving. Tip life improved from 500 to 2500 hits for the larger hole and from 500 to 2000 hits for the smaller. A substantial contributor to the labor saving was elimination of deburring, a consequence of the edge chipping that plagued the original process.
After running the step drill for about a year, Ford engineers considered adding the 60° chamfer to impart a feature to the hole that required an additional operation and an extra tool. Ingersoll created the custom tool, resulting in an 11-sec cycle time saving for every two cranks (they're done two-up), and removing one tool from the operation. The additional chamfer not only eliminated the separate operation, it also outlasted the original chamfering tool by 5:1.
"These savings don't include eliminating the reconditioning merry go round that inevitably accompanies solid-carbide drills in high-volume operations," says Margerison. "Given the typical 4–15 week turnaround time for reconditioning solid-carbide tools, a plant would need to inventory three to six drills for every one in active service. And with the premature and unpredictable failures at Ford, that number would have to be much higher. With a replaceable-point drill, by contrast, you need just a couple of alloy steel shanks and a supply of replaceable points."
Introduced in 2000 by Ingersoll, the Qwik-Twist drill has made the greatest impact replacing solid-carbide drills in high-volume drilling operations such as Ford-Windsor's. Users report dramatic reductions in tool inventory and reconditioning costs. The reusable drill body is fluted alloy steel for toughness, and shock and impact-resistance. Only the replaceable point is coated carbide.
In just 20 sec, often right in the spindle, the operator locks a new point in place with a key tool much like an Allen wrench. The points lock in place with ±0.002" (±0.05-mm) axial-length repeatability, eliminating the need for touching off after each point change.
Points are self-centering and available in geometries for either general-purpose or cast-iron drilling. Diameters cover the range from 0.268 to 1.020" (6.8–C25.9 mm), in 0.004" (0.1-mm) increments. Bodies are available in 3:1, 5:1, and 8:1 length-to-diam (L/D) ratios, all with through-the-tool coolant delivery. To further reduce tooling inventories, one body can accommodate up to ten different-size tips.
Sourcing Prototype Parts for IRL Testing
In IRL IndyCar Series racing, there's a very delicate balance of design and manufacturing, speed, aerodynamics and driver skill to produce a winner. If you ask one of the US suppliers of IRL chassis to identify a single pivotal aspect, they'll tell you testing, testing, and more testing. The challenge is finding suppliers to manufacture the one or two-off parts critical to that testing.
Michael Koenigs, aerodynamicist with Elan Motorsports Technologies (EMT; Braselton, GA) spends a lot of time testing Panoz IRL cars. Not on the track, but at the Penske Technology Group's wind tunnel in Mooresville, NC. "We test once a month, and what we learn in the tunnel program directly impacts the final configuration of these race cars, which routinely average in excess of 200 mph [322 km/hr] on the course," says Koenigs.
EMT-produced chassis have won several Indianapolis 500 races and are branded as Panoz, after the company's owner, Don Panoz.
Koenigs says that all race cars are designed and built in-house, including the Panoz IRL chassis, the America LeMans entry, which is the Esparante GTLM car based on Panoz Auto Development's Esparante production road car, the Star Mazda cars, and a number of NASCAR simulators that you see in shopping malls.
For the IRL program Elan manufactures the entire car, front to back, minus the engine—the hand layup and molding of composite tubs, all of the carbon bodywork, the fabrication of radiators, pipes, and ducting. "For the Panoz IRL cars we deliver a rolling chassis to the various teams, and they install their own engines from Chevrolet, Honda, or Toyota."
It takes about two weeks to turn around a standard IRL car, says Koenigs, and that's from start to finished rolling chassis. Critical to the overall design process is wind-tunnel testing. "Our wind-tunnel model is an exact 50% reproduction of the IRL race car. Everything is scaled down, including a representative transmission and engine, the wheels, the uprights, the suspension, and all of the aerodynamic surfaces." Koenigs says that they may go into the wind tunnel on a Monday, test all week, return to Elan on the following Monday, and implement on the actual race car the nuances in design that they've learned through testing.
While the actual production cars are manufactured in-house by Elan, many of the parts and components for the wind tunnel models are outsourced. "When the model shop opened in the US in January 2004, the primary process for sourcing parts was to generate drawings and hand them off to our purchasing department to find suppliers to quote the item, and then generate an order. This was not the most efficient process for the models due to the time-critical nature of most parts, and the controls required to produce acceptable parts."
Koenigs took charge of the quoting process "to gain more control over scheduling as well as cost and quality." Through searching for alternative suppliers other than current local vendors used in the full-scale race cars, Koenigs came across Mfg.com, an interactive web service enabling manufacturers to buy and sell custom manufacturing services. Buyers post RFQs at no cost; suppliers quote for business that meets their expertise and capacity.
"This has proved to be the best solution to what we were looking for," says Koenigs. "We are now able to source our three-axis and five-axis CNC jobs in days—jobs that would normally take two, three, or four months just to find a decent supplier. Using Mfg.com, we can send out RFQs across the country, as well as Canada, and locate the right suppliers in a shorter period."
This article was first published in the January 2007 edition of Manufacturing Engineering magazine.
Published Date : 1/1/2007