Shop Solutions: HSM Turbocharges 24/7 Automation
Compile a list of requirements that drive manufacturers to automate and you probably wouldn't include a company mission statement, especially one that is based on the founder's religious convictions against allowing company staff to work on Sundays.
That is precisely what has led to a commitment to automation at Turbocam Inc. (Barrington, NH) by its chairman and founder, Marian B. Noronha. His company is a global producer of complex, precision-machined turbomachinery parts with two plants in the US, one in the UK, and one in India.
Turbocam Automated Production Systems (TAPS) division relies on five-axis high-speed machining centers from Mikron (Lincolnshire, IL) to produce truck turbocharger impellers in the quantities needed and at the prices demanded by truck and automobile makers.
Turbocam's business is growing with the increased demand for the impellers, which are the key to producing turbocharger compressors, and meeting horsepower requirements and exhaust-emissions standards.
Five years ago, Turbocam was focused on relatively low-volume, high-precision five-axis machined parts. That was before some very large automotive and truck industry suppliers came looking for a solution to a growing problem.
Historically, most turbocharger impellers were cast, not machined. The parts were relatively inexpensive, around $10 in some cases. But the aluminum was a low-quality alloy and just not up to modern turbocharged engine conditions, and the higher operating temperatures and pressures required to meet stringent engine performance and emissions standards.
The situation in the highly competitive diesel truck industry was becoming critical as turbo impellers were failing early and engine performance was being compromised. The turbocharger industry began to search in earnest for alternatives to cast parts.
"When the main tier OEM impeller suppliers made visits to us to see how we would solve the problem, we saw no alternative but to machine the parts from solid," explains Noronha. "Our first price quote came in around $400 each, which naturally was cost-prohibitive."
The Turbocam price would have to come down 90% to make machining a viable alternative to casting. With the turbocharged engine stimulating significant market growth, especially in the commercial truck segment, the challenge was to make machining from the solid competitive with casting.
Intrigued by the volume and the challenge, Noronha and his team took a close look at state-of-the-art machining, automation systems, and five-axis CAM software.
"We had been automated since 1988, but now we were talking multiple part changes and running through the night and through the weekend with complete reliability. We looked at various machining systems, observed trade show demonstrations, and studied the available software," recalls Noronha. "We knew we needed total automation, speed, and five-axis machining for the nonstandard impeller shapes."
It was a monumental decision, and an investment that would make or break Turbocam as a business. In 2001, Turbocam launched its TAPS division with a three-man pilot plant capable of round-the-clock untended manufacturing of large numbers of impellers. And it worked.
TAPS division recently moved to a new world-class 100,000 ft2 (9290-m2) manufacturing and headquarters facility situated on 28 wooded acres in Barrington, NH. Turbocam's 60 five-axis machines and 225 employees specialize in making turbocharger compressor impellers for internal combustion engines, and blisks and impellers for jet engines.
The new facility is the home of 18 of 25 Mikron HSM 400U high-speed machining centers, most with pallet changers. The plant is dedicated solely to producing some 20 variations of truck turbocharger impellers in the hundreds of thousands from wrought aluminum, stainless steel, and titanium billet.
Noronha, a devout Christian and innovative technologist, believes that automation and the HSMs can provide the reliability to operate untended. "There are only two people monitoring our machines evenings and nights during the work week," Noronha explains. "On Sunday, the machines operate untended. We are a textbook lights-out operation. A lot of people talk about automation, but we are truly doing it."
The HSM decision was critical. Turbocam needed machining centers that could work full-tilt at the very extremes of their performance capabilities. "We decided Mikron had the best offering in overall machining speed and pallet changing-capabilities," says Noronha. "They had the pallet changer we needed, and were suitable for the customization we planned."
The HSM 400 U's feature a built-in standard laser measurement system that monitors the lengths and radii of tools, and a standard linear measuring system with glass scales that ensures high positional accuracy. Most important, they have very accurate and dynamic machine motion with the high accel/decel (greater than 1g) needed for fast, continuous machining of the complex, helically-shaped impellers. With constantly shifting cutting paths along all machine axes, impellers demand machines that can provide both speed and accuracy.
"Fixturing, setup, part-changing, and control are all strong features of this machine," says Andrew Hussey, TAPS engineering manager. "The Mikrons require less up-front programming and tuning—half the time versus our other systems. I attribute that to the controller and machine tool geometry."
Part finish and accuracy are also a result of the patented, concrete polymer base of the HSM 400U, which provides rigidity, vibration dampening, and high thermal stability, resulting in workpiece surface quality and minimal tool wear.
The Barrington plant has six robotic cells served by ABB and 3-R robots, with three of the robots tied in with Mikron machining centers. Automated conveyors keep a steady stream of workpieces coming.
"The smaller impellers have run times around a half-hour," explains Hussey. "That's 150 parts feeding two machines at one-half hour per part, and you get roughly 37.5 hr of untended run time from Saturday to Monday morning. We aim for 100% total available machine uptime, and hit 80% for around 135 hours of production per week," Hussey says. "In our operation, reliability is a huge factor, and the Mikrons are reliable."
High-speed machining, the Turbocam way, requires speed in all phases of the operation. The Mikron machines use linear motor technology, the design and construction of the machines' rotary axes permit speeds up to 25 times those possible with conventional rotary tables. The spindle motors are liquid-cooled and have hybrid ceramic ball bearings to help achieve the typical speeds of 40,000 rpm for TAPS' applications.
One of the keys to Turbocam's success has been its ability to customize and write five-axis CAM software. Turbocam has five software programmers working to customize and optimize the software and process. "We have twenty people who can do five-axis programming, and all engineers must learn this when they join the company," Noronha points out. "It takes approximately two years of training to become a competent engineer/programmer at Turbocam."
In November 2000, Turbocam and a Canadian software company, CAMplete Solutions Inc. (Waterloo, ON, Canada), teamed up to create proprietary software that optimizes Turbocam's five-axis machining accuracy, speed, and quality.
The software has been so successful that Turbocam and CAMplete are marketing a version of it known as TruePath. Using C++ code, Turbocam edits and modifies toolpaths in TruePath after programming in CAMAX. (Mikron also markets CAMplete Software ).
"Our machinists use TruePath to edit and modify toolpaths for the HSM 400U operations. A virtual editing tool is the best way to explain it. TruePath helps you reduce mistakes, estimate cycle times, and figure out the optimum feed-rate and more," explains Hussey.
Today, the TAPS plant produces more than 200,000 truck turbocharger components a year. With the new plant, capacity exists for 250,000–300,000 impellers per year.
"To make a highly automated process work well, your staff has to be available to support the process whenever needed, rather than according to some rigid schedule," explains Noronha. The Turbocam staff have embraced this philosophy and made the process work. They continue to innovate and streamline the production of these highly demanding turbocharger impellers.
VMC Delivers Precision Jobs
Short-run, close-tolerance work for medical or aerospace parts is there to be had by manufacturers that can meet the performance requirements.
For KBK Tool & Manufacturing Inc. (Skokie, IL) that meant finding the right equipment to do what its conventional equipment could not do by reaming or boring, i.e. hold total tolerances of 0.0005" (0.0127 mm) on shallow bores 0.1125" (2.86-mm) deep and 0.375" (9.53-mm) diam.
Owner Ken Hedeen explains: "I really wanted to do these bores with an end mill and interpolate, but couldn't do it with our present equipment. So I began to consider new equipment to tackle this type of work."
For more than two decades, KBK has specialized in CNC milling and turning of basically any type of material, including stainless steel, carbon steel, aluminum, heat-resistant steel, titanium, and plastic. "Just about anything that's machinable," says Hedeen.
Right now, KBK's business mix is about 75% medical, 15% aerospace, 5% office equipment, and another 5% miscellaneous work. The company's capabilities extend from prototyping to volume production with the ability to meet military specs for heat treating, welding, lapping, NDT, painting, and finishing.
For its medical device customers, the company produces about 70% of the machined parts that go into medical diagnostic equipment and surgical instruments. "These kinds of customers expect and require very close tolerance, ultraprecision parts and are pretty uncompromising," says Hedeen.
KBK selected a Bridgeport 760 XP3 VMC from Hardinge Inc. (Elmira, NY) to meet the demanding machining required of it. "At the beginning of my search for a machining center, I was unaware that Bridgeport offered such high-end solutions with their XP3 line."
KBK needed the new machine right away and didn't have time to look through the manuals thoroughly to become familiar with machine capabilities. The new 760 XP3 was put to work making parts and holding the tolerances it promised.
"My programmer came up to me and told me he is holding true position of 0.001" [0.03 mm] and that he programmed the first part and it came out perfect. He'd had to make no adjustments whatsoever, and, in all his years of programming experience, he had never been able to do that," Hedeen says.
Once KBK became aware of the high-speed options of the XP3, the company was able to speed interpolation feed rate from 6 ipm (152 mm/min) to 30 ipm (762 mm/min), and reduce cycle times by one-third. "These parts are aluminum, and the cycle times had been 45 to 50 minutes," says Hedeen. "Now that time had been cut by 30%. We had run a lot of these parts and the job was just about done. I know I left a lot of money on the table on that job, but that's what happens when you buy a machine like this and have to put it to work right away, and don't have the time to really investigate all the options and capabilities. We just had to get it in and begin producing parts right away," Hedeen explains.
Gaining experience with the XP3 enabled Hedeen to develop the best machining strategy for his operation and turn jobs around quickly for KBK's customers. "We often use fixture plates on the machine, especially if we know we're going to be repeating the job," says Hedeen.
"With repeat work, we throw the fixture on, call up the program, and go. And one of things I really like, for a couple of reasons, is the 30-tool side-mounted swing-arm ATC. It's really handy because we can leave some tools in the changer, and when those jobs repeat, our setup time is negligible. The tools are already there, and the program has been loaded in the control. A job that may have taken four to eight hours to program and set up has now been replaced by putting a fixture plate on and calling up the program. The difference is time-in-cut instead of idle time."
The other thing that Hedeen likes about the Bridgeport toolchanger is that it's mounted to a fully supported shoulder on the machine's column, which is engineered to support its weight, thus eliminating the transfer of vibration into the cutter while the toolchanger is rotating.
Consistency between parts made at the beginning of the day and parts made at the end of the day has been improved by two features of the XP3 machining center: a cooling system that reduces heat in the head, and a thermal compensation system.
"The Bridgeport has allowed us to go after work we couldn't previously do," says Hedeen. "I'll be honest, I quoted jobs that I really thought I could do, but no matter what we tried, until the Bridgeport, we couldn't actually run some of these jobs."
After acquiring the Bridgeport, KBK acquired a Zeiss CMM to provide complete traceability for medical and aerospace parts, certifying the material, and any grinding or heat treating that's done to the part.
The 760XP3 has extended KBK's capacity for demanding precision machining jobs. "We're able to go after jobs we wouldn't have thought about before the Bridgeport. We're typically hitting tolerances of 0.0005" [0.0127 mm], total not plus or minus, and we hit 0.0003" [0.0076 mm] as well."
The 760XP3 has X-axis travels of 30" (762 mm) and Y, Z-axis travels of 24" (610 mm). Rapid traverse rates are 1690 ipm (43 m/min) in X, Y and 1410 ipm (36 m/min) in the Z axis. Worktable surface is 35.4 x 23.6" (899 x 599 mm) and table load is 1500 lb (680 kg). Spindle speed is 12,000 rpm with 25 hp (18.7 kW). Machine control is supplied by a Fanuc 18iMB CNC with a fourthaxis optional capability.
"We've been very pleased with the accuracy of the parts we're making and the finishes we're seeing," says Hedeen, noting that the company has had the Bridgeport 760 XP3 for just about a year without any problems.
TV American Chopper Shop Ramps Up
American Chopper is a unique slice of Americana that lets cable TV viewers look over the shoulders of the designers and machinists at Orange County Choppers (OCC) as they conceive and build one-of-a-kind chopperstyle motorcycles and accessories.
The program is shot in a machining and fabrication reality environment complete with a big mustached boss who sometimes explodes when work lags behind schedule. OCC makes just about all parts using steel and aluminum, and operates advanced manufacturing equipment that any shop would be proud of.
OCC is very high tech. They rely on a Flow waterjet system capable of cutting through ceramic, glass, even a 12" (305-mm) block of steel, with minimal heat and no distortion of the material. They use a mandrel tube bender to create unique snaking exhaust systems without leaving any ripples in the metal. Advanced CNC lathes and mills turn and cut these exotic and beautiful parts.
OCC uses Mastercam CAD/CAM software from CNC Software Inc. (Tolland, CT) to program its five CNC machines. OCC seamlessly imports designs from SolidWorks, IGES, or other CAD files into the Mastercam CAM program, and translates them into programs for its Haas machines.
The point of one-off chopper building is to make an artistic statement, not flood the market with loads of look-alike bikes. So in 1999, when veteran machinist and biker Paul Teutul became serious about the business (moving it out of his basement), he thought production would probably max out at three choppers a year.
When the Discovery Channel caught up with him in 2001, production was somewhat higher because he had two people working with him. Later, as OCC bikes were seen by millions of TV viewers, the roof would blow off.
In the beginning, OCC used a lot of standard parts and components purchased from other manufacturers. Today, the entire bike is what lead engineer Jim Quinn calls an open canvas. In other words, most of what is visible on the bike is designed and manufactured by OCC.
In six frenetic years, Discovery Channel viewers have watched OCC grow from three employees to 60 (including the boss's two sons, Mike and Paul Jr.), and boost its production to 80 commissioned custom choppers in 2005.
With millions of viewers following the exploits of American Chopper, OCC is poised to make some of the company's merchandise available to loyal fans who cannot afford custom choppers that range upwards from $40,000.
The first step will be a move into a new 100,000 ft2 (9290 m2) facility. This plant will allow OCC to ramp up production to the point where it can produce a small line of limited-edition bikes, and boost overall production to 120 bikes in 2006 and as many as 200 in 2007.
The old 30,000 ft.2 (2790 m2) plant will become the CNC production shop. Quinn said that OCC will have to streamline its manufacturing procedures to achieve output targets, and will use Mastercam to refine or redesign tooling and fixtures for increased productivity.
For example, an adjustable jig used to fabricate custom bike frames will be redesigned for production of limited-edition vehicles. The custom jig makes it possible to adjust the bike's rise and stretch to make each bike's dimensions proportional to the measurements and/or tastes of the person who will be riding it most often. It has been a great timesaver in building custom bikes.
The adjustable frame jig is an idea being worked on by OCC employee and frame welder Craig Chapman. Craig made initial sketches of the concept, which then were further designed and implemented in three dimensions using Mastercam.
"Once we are ready to make hundreds of bikes with the same rake and stretch specifications, we already have that jig designed in Mastercam," explains Quinn. "It will be quite easy to go back in and duplicate the dimensions we need, take out a lot of the adjustability, and generate the CNC programs to make our production jig." The same concept also holds for other tooling and fixtures that will need to be transitioned from a custom to a semiproduction manufacturing environment.
Along with building limited-edition bikes, OCC intends to cherry-pick its custom part, accessory, and wheel designs to identify the ones that would be most appealing to fans. It will manufacture these signature parts on a production basis. The Nasty Wheel, the engraved OCC logo air cleaner cover, and the OCC Dagger Shield coil cover will be among the first made in production runs. The latter is the company's signature accessory, which they have used repeatedly on the custom bikes. The CNC machining process for the Dagger Shield has already been significantly streamlined.
The full 3-D Dagger Shield part consists of a highly detailed sword against the background of a rounded shield with rounded edges. The workpiece is precision-cut by waterjet from a standard 2.5 x 12 x 72" (63.5 mm x 305 mm x 1.8-m) aluminum billet, reducing the cost compared to using a custom-forged workpiece. Precise nesting of the part on the billet maximizes the number of parts that can be taken from a single billet, and minimizes the excess stock removal to only 0.030–0.040" (0.76–1-mm) around the outer edges of the shield. Quinn explains that to create enough space to hold wiring and other components within the cover, the walls had to be kept to about 0.100" (2.54 mm). This made workholding a challenge.
The part was designed in Solid-Works and imported into Mastercam. "Because the workpiece is already cut to near-net shape with only light cuts required around the perimeter of the shield, the part can be cut at higher speed with less tooling force for a faster production cycle and better surface finish," Quinn explains.
"I use the 3-D surfacing toolpath capability in Mastercam to get the detail of that dagger on the part, pulling a parallel plane, machining in two different directions first using an 1/8" (3.175-mm) ball mill and then a 1/16" (1.5875-mm) ball mill. The part comes out pretty near polished. The polishing that we have to do on it to get it ready for chroming is very minimal. Our chromer loves it. The dagger holds its detail standing up off that shield in chrome, and everything else is nice and smooth," Quinn says. The first couple of times this part was made on a prototype basis, the complete process took about six hours. Now, after tweaking the various steps, they have the time down to 1½ hr. The part is production-ready.
This article was first published in the September 2006 edition of Manufacturing Engineering magazine.