Shop Solutions: Mill-Turn Shines in Reducing Cycle Times 50%
People whose lives may depend on having enough light when they need it, like military and emergency personnel, rely on high-performance illumination tools from SureFire LLC (Fountain Valley, CA). SureFire is a manufacturer of flashlights, weapon-mounted lights, and other tactical equipment favored by SWAT teams and elite special-ops groups.
Users increasingly are outdoorsmen involved in hunting or fishing in need of a dependable light source. In December 2009, SureFire's Founder and President John Matthews was named one of Outdoor Life magazine's Top 25 people who have changed the face of hunting and fishing with his company's innovative products.
SureFire illumination tools are engineered for maximum performance and manufactured to precision standards to produce brilliant light beams with no rings, hot spots, or shadows. The aluminum-body lights are machined from a high-strength, aerospace-grade alloy, making them extremely resistant to damage from impact, crushing, or bending, and allowing them to be made as small and light as possible without sacrificing strength.
To machine these parts, SureFire relies on multitask milling and turning machines from Index Corp. (Nobleville, IN) to minimize cycle times and reduce the need for operator attendance.
Gustav Bonse, SureFire's executive vice president-machining operations, explains: "The reason we are so successful with the Index machines is that they drop complex parts complete. The cycle times are very fast, and the machines don't require constant operator attendance."
SureFire, which started manufacturing 11 years ago with Index machines, recently took delivery of a 65-mm barcapacity Index C200 mill-turn, an investment that is already paying dividends. The mill-turn machine allows SureFire to reduce cycle times on the parts it produces on average by 30–50%, and to replace several older machines with a single C200.
"I am constantly trying to eliminate secondary operations on each part we produce," says Bonse, "because it is too expensive to approach machining otherwise. Whatever comes off the machine has to be complete."
The C200 is equipped with 5000-rpm spindles and can run parts to 200-mm long. With three 14-position tool turrets, a 160-mm chuck, and identical, liquid-cooled main and counter spindles, the C200 is designed for fast production of medium-complexity parts turned from bar. Each of the C200's 42-tool complement can be driven. Up to three tools can be on SureFire's work simultaneously, which helps the company produce some difficult parts not only in a single setup, but with minimum cycle times.
Idle times on the C200 have been reduced greatly. Turrets are lighter, having less mass, and feature 30 m/min rapid traverse for quick positioning. And the work envelope is designed to reduce travel.
"If you want to run a part quickly, minimize indexing travel," says Bonse. "I move the tools only 0.300" [7.6 mm] in front of the part, so I have much less noncutting time than a shop, for example, that makes the turret move farther away from the part. It saves a lot of cycle time. But to do this you have to be able to be consistent in tools each time you run the part."
The toolholding system is the key to controlling indexing travel. Tools lock with only one screw and feature the Index W-serration in the base of the toolholder, an Indexspecific improved VDI interface that ensures repetitive accuracies of ±8 µm up to 100 mm from the mounting surface. "The tool is held rigidly and does not move, making setup faster because we don't have to align the holder anymore," he says.
The W-serration in the toolholders is credited with increasing tool life by 20–50%, depending on the material SureFire is cutting.
Simultaneous machining with two Y axes, one at the main spindle and one shared between the main spindle and the counter spindle—each with 70-mm travel—gives SureFire the option of dividing machining operations for optimum machining efficiency and flexibility. This freedom also is a key to reduced cycle times.
The two Y axes allow SureFire to work on both sides of a part at one time, reducing cycle times. Off-center machining can also be done simultaneously. Three tools can be at work simultaneously—driven or fixed—including backworking tools. And the counterspindle, which has a driven Z axis, can be synchronized with the travel of turret three. Counterspindle pickup from the main spindle is accomplished in 1.5 sec.
"What really works for us on the C200 are the two Y axes," Bonse says. "Many of our parts require a machine with a Y axis to machine them complete; with two Y axes, I can machine top and bottom [180° opposite] of a part simultaneously, saving cycle time. This can easily save us 50%, with circular milling, slotting, drilling, and other machining."
The turret slides move in the X and Z directions on the Index SingleSlide plate-type slide system. This system, unique to Index, permits rapids up to 60 m/min and accelerations up to 1 g with maximum rigidity. The plate-type guideway of the turret slides also means turrets glide directly on the machine bed, ensuring high stiffness and damping, resulting in longer tool life and better surface finish.
SureFire is careful to assign parts to the appropriate machine. "The C200 provides us flexibility–both processing and changeover. I can tool it up tomorrow for entirely different parts," Bonse says. "It is extremely important for us to provide what the market needs in a timely manner."
"Our setup times in the shop may be 1 min 30 sec to 1.5 days, depending on how many tools we have to change, and whether we have to change bar feeders. But in most cases the machines always run the same bar size, and are already tooled up to produce four to five different parts each, so all we have to do is change part programs, and setup is done in a minute or less," Bonse says.
Minimizing setup time in the shop is extremely important for not only cost, but throughput. "We make nearly 800 different parts in the plant, producing from 250,000 to 300,000 complete parts a week in stainless, aluminum, and Inconel, ready for shipment to our assembly plants. Each part will have from 8 to 35 operations. And on some new parts we will have up to 60 operations per part," Bonse says.
Index Virtual Machine allows SureFire to simulate part programs as they would run on the actual machine without any risk, maximizing production on the machine tool and keeping programming offline. The identical user software mirrors the real configuration data so SureFire can program, set up, and operate the "virtual machine" in exactly the same manner as the real machine.
The Index Virtual Machine, which contains a copy of the Siemens CNC kernel of the Sinumerik S840D control, and which can carry out a 3-D machine modeling down to the last detail in the Tecnomatix simulation system, directly executes the CNC program.
"Where Virtual Machine really has an impact on my operation is that it allows me to get a collision-free program to the machine," Bonse says. "Everything you see on the Virtual Machine screen is 1:1, exactly as it is on the machine itself. Two programmers use the virtual Machine to program our C200, Siemens-controlled machines. Into the software, we can add each one of our specific tools," Gustav adds.
The Index strategy has worked well for SureFire, helping it keep its products ahead of the competition wherever it comes from, local or offshore. The production and quality are always there, and because SureFire is consistent with Index, personnel need to be trained on only one type of machine, the same tooling system is used throughout, and spare parts can be shared.
For more information on Index Corp., go to http://www.index-werke.de/ic/englisch/index_ENU_HTML.htm or phone: 317.770.6311.
Job Shop of the Future,Today
In a changing economy with many types of parts, and even entire industries going to other countries for production, job shops have had to evolve in an upward spiral of innovation to rise to the top.
In those shops that are thriving today, three concepts emerge as common denominators: automation, sophistication, and flexibility. Of course, that's what's going on inside. Poplar Hill Machine (Conway, MA), for example, is located off a dirt road on a hillside among giant poplar trees, and just steps away from owner Michael Kurkulonis' home. Built in 2007, it's a spacious 9000 ft2 (836 m2) building.
While even a GPS might get stumped trying to find it, chances are some of the parts that relate to that device are made there. Satellite, microwave, telecommunications, and medical components are among the complex, specialized parts that Poplar Hill makes for several OEMs. You can bet they know how to find it.
Kurkulonis's business strategy has been to use the most advanced machine tools and automation to manufacture high-tech parts for specialized high-tech industries. Applying that philosophy, he quickly grew out of the garage where he had started the business.
CNC machines from Hurco, Kitamura, Brother, and Okuma do the precision machining on the shop floor. At a nearby PC station, CNC programmer John Hill uses Mastercam X4 CAD/CAM software from CNC Software Inc. (Tolland, CT) to execute prototype designs and generate efficient cutting toolpaths for the various machine tools.
Microwave radio telecommunications is one of the leading areas of new business at Poplar Hill. It's an emerging field requiring some of the most challenging parts the company makes, such as waveguides. Microwaves are electromagnetic waves with wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. Waveguides direct or channel microwaves.
Kurkulonis has produced components for his customers with as few as one waveguide, and others with hundreds. He believes that microwave radio telecommunications will replace cable-driven communications, as it brings advanced technology to remote parts of the country and the world, and plays an increasingly important role in the defense industry.
"We typically use 0.005–0.015" [0.13–0.38-mm] diam end mills to make most of these waveguide parts," says Kurkulonis. "Many of the features in these parts can't have burrs, and we're not allowed to deburr them. Wherever the electromagnetic wave for the microwave is traveling, it has to have sharp, crisp edges everywhere."
One of the problems with a former CAD/CAM software package Poplar Hill was using was that the programmer couldn't specify the entry/exit motion, where to start and stop, or how to machine certain features. It had a number of preset strategies, and when all failed, it either plunged into the part or failed completely. No one, including the developer, could relay to Hill what the formulas for these strategies were. This made programming very difficult at times.
"With Mastercam all that went away," says Hill. "I'm now able to tell the software exactly where to start and end, what entry/exit motion to use, and how to machine it."
Other shops have tried to take on these parts because, at first glance, they appear rather simple. But the customer rejects them because of the tiny burrs and little lips and miniscule edges that they can't get out, not knowing how to machine them and not realizing that their CAM package could be limiting them by almost doing the thinking for them, instead of letting the programmer intercede.
Messrs. Hill and Kurkulonis explain: "That has been the biggest plus for Mastercam here. We have specific ways of machining, which are proprietary, that we have to do. We're not limited by some software engineer's belief that, according to the Machinist's Handbook, this is what they should be doing, so let's program it in so they don't ever make a mistake. Happily, Mastercam gives us the flexibility to machine parts our way."
The waveguide parts must come off the machine ready to be assembled, ready to be plated, and sometimes are shipped directly to inventory—bypassing the customer's quality control department. The machines of choice at Poplar Hill for this work are the Kitamura MyCenter-250s and an Okuma MA-400HA Space Center HMC with an ATC that carries 198 different tools, and an automated pallet exchanger with 12 pallets that allows operation on a 24-hr basis, every day of the week.
The Okuma was purchased in 2008 after a thorough examination of alternate machines. The Okuma's accuracy, speed, and range of functions met the criteria necessary to machine the waveguide and other fussy parts at the company. The high-speed machining package in Mastercam has complemented the inherent design of the Okuma and Kurkulonis's "lights out" operation.
For more information on Mastercam/CNC Software Inc., go to: www.mastercam.com or phone: 860.875.5006.
Tap Technology Delivers Big Savings
Cutting-tool technology is always on the move with cutting-tool manufacturers constantly developing new tooling designs to increase cutting speeds and extend tool life. Staying updated with the latest innovations can help reduce cycle times and manufacturing costs, even if the application's current production method appears adequate.
Taking this critical factor into consideration, Messrs. Mike Hickey and Mike Brzezniak, district managers with OSG Tap & Die Inc. (Glendale Heights, IL) approached FMC Technologies Subsea Services division (Houston) with OSG's Hy-Pro-HXL and Hy-Pro-VXL taps in hand, knowing that these taps could offer FMC greater tool life and cost-per-hole savings.
FMC Technologies is a global provider of technology solutions for the energy industry. FMC designs, manufactures, and services technologically sophisticated systems and products such as subsea production and processing systems, surface wellhead systems, high-pressure fluid control equipment, measurement solutions, and marine loading systems for the oil and gas industry.
FMC Technologies' Subsea Services division in Houston has approximately 2000 employees, and occupies a 390,000 ft2 (36,232 m2) manufacturing facility. The Surface Wellhead division supplies drilling, completion and production systems for onshore and offshore applications. By eliminating steps in drilling and completion operations, FMC equipment helps customers reduce rig time and improve rig-crew safety.
Prior to the introduction of OSG's Hy-Pro-HXL and Hy-Pro-VXL taps, FMC Technologies used a spiral flute tap to produce threads in surface wellheads, which are used to control pressure during drilling and monitor casing annulus pressures during production. The part that FMC Technologies machines is called the crossover valve block, a part it has been producing for more than 10 years. FMC Technologies produces approximately 10–15 parts per week. Over 1000 parts are produced each year.
Crossover valve blocks are machined from 4140 alloy steel using an HMC. Each part includes roughly 8–16 blind holes with flat bottoms. Each hole is approximately 0.875" (22 mm) in diam and 3.125" (79-mm) deep. The volume of the crossover valve block varies from 1500 to 2500 in.2.
The level of productivity was targeted at 400–500 holes with the spiral flute tap. By no means was FMC Technologies dissatisfied with these taps. However, they were willing to accept a free tooling trial offered by Messrs. Hickey and Brzezniak, because the duo claimed that OSG's Hy-Pro HXL and VXL taps could produce superior results.
The OSG Hy-Pro-HXL and Hy-Pro-VXL taps are designed to excel in applications in any industry, producing threads over 1/2" (12.7 mm) in diam. Oil, gas, and wind energy are all considered primary industries for applications of these taps, because they commonly deal with threading of large-diameter holes, often with reduced or limited machine capability, which these taps are engineered to handle.
The Hy-Pro-HXL, designed for horizontal applications, breaks chips into a manageable size that evacuate with normal coolant flow. The Hy-Pro-VXL, designed for vertical applications, produces longer, tightly wound chips that evacuate and break off away from the shank of the tap. A highlight feature of both taps is their ability to effectively control chips to eliminate "bird-nesting."
"The spiral flute taps we used were expensive but they rarely have any problems," says Joe Sotelo, FMC Technologies' manufacturing supervisor. "However, the test trial showed the superiority of OSG's Hy-Pro-HXL taps. They could do more holes and cost less. So, we requested our on-site integrator [Groves/DGI] to replace the German spiral flute taps with HXL."
The spiral flute taps FMC Technologies previously used were capable of generating 400.500 holes per tap. Running at the same speed at 50 fpm (15.2 m\min), OSG's 1"-8 Hy-Pro-HXL and Hy-Pro-VXL taps were making 3000 holes per tap. The price of OSG's Hy-Pro taps are approximately 10.20% lower than the spiral flute taps that FMC Technologies previously used.
For more information on OSG Tap & Die, go to www.osgtool.com, or phone: 630.790.1400.
Fixturing Removes Production Bottleneck
Bombardier Aerospace in Wichita, KS, produces Bombardier Learjet Models 40, 45 and 60 business jets. When Drew Hanus, methods engineer, was assigned a project that required increasing productivity, he turned to Advanced Machine & Engineering (AME; Rockford, IL) for assistance. Hanus was already familiar with AME's products from previous experience with the company.
Bombardier was running 240 different parts through a cell comprising four horizontal, four-axis machines with a 28-pallet system and one vertical, five-axis machine with an eightpallet system. The bottleneck was obvious to Dietmar Goellner, AME CEO, Alvin Goellner, fixturing group product manager, and Jim Park, AME's representative, when they visited the Wichita facility.
The setup would often paralyze production where dedicated fixturing had been used for years to make the individual components on standalone machines or smaller workcells. Having determined they wanted to utilize as much legacy equipment as possible, Bombardier was confronted with excessive changeover and setup times.
The contact with AME was made to explore other possibilities for fixturing, using standard or semicustom modular devices. AME's team of experts demonstrated the advantages of subplates with hardened precision bushings and hardened threaded inserts on a 2" (51-mm) grid system. Because Hanus and his team at the Wichita facility needed to change parts quickly from one setup to the next, AME demonstrated how gridded tombstones and plates, along with modular components, would allow them to locate and align very accurately and quickly on a 2" precision grid system.
Bombardier purchased several full-grid tombstones to be used with their palletized system along with various subplates, components, and precision dowel screws, which could be used for locating fixture plates onto tombstones or their pallets for quick changeover.
Advanced Machine & Engineering manufactures workholding fixtures, tombstones, and components, and provides design/build services for CNC HMCs and VMCs, and other CNC machines. All products are designed to handle workholding projects from CAD/CAM, to build, to ship. Their North American facilities feature five different types of machinery, multiple grinding departments, temperature-controlled CMMs, an extensive inventory of replacement parts, and complete design/build and technical-consulting services.
Precision grid bases can typically be made by AME in any size and shape to a customer's exact specifications to fit any CNC machines. All grid bases are available in four styles:
- Type NH—no holes
- Type TH—tapped holes
- Type BT—bored and tapped holes
- Type S.A.F.E.—precision hardened bushings and hardened-steel threaded inserts
Precision S.A.F.E. Lock Plates will mount on any of the grid bases, and are not limited to use with cubes, double angles, single angles, etc. Mounting horizontally or vertically for quick-change dedicated machining, they locate accurately by using any two of the four precision hardened bushing holes with our precision dowel screws.
The last option, the Type S.A.F.E. grid base, was determined to be the best-suited to Bombardier's specific requirements. Bombardier's pallets were shipped to AME, where the manufacturer incorporated bushings and threaded inserts along with locating and mounting holes. A 2" grid system was integrated into the customer's pallets, and all were inspected with AME's CMM machine, one of the largest in the industry. Calibration blocks were added to check the probe for repeatability of the machines. These show when and where adjustments were needed to hold 0.0002" (0.01 mm) accuracy. A rotary axis check was also done on the fourth-axis rotary table to ensure accuracy.
Today, 800 different parts are being run through two cells at the Bombardier plant in Wichita. Monolithic parts are run on one setup. Currently, Bombardier enjoys 91% savings on setup time and a total saving of 81% on cycle time when compared to the old dedicated system, according to company management. A future project will involve additional modular components for the system.
"The new system played a major role in allowing us to achieve our six-sigma goals for this segment of our fabrication process," says Hanus. "We now have improved setup time, we are producing better-quality parts, and we're saving money."
For more information about Advanced Machine & Engineering, go to www.ame.com, or phone: 815.962.6076.
This article was first published in the March 2010 edition of Manufacturing Engineering magazine.