Shop Solutions: Helicopters Fly High on Ceramic Bearings
If Reliance Tool & Manufacturing Co.’s research and test-cutting operations continue to progress at their current pace, the Elgin, IL shop foresees it will soon be able to cost effectively produce an entire ceramic bearing assembly, not just rollers, but also the races. Reliance is developing optimized machining processes for extremely hard ceramic materials, such as those in the Rc 80 range. These materials and processes will then be incorporated to produce ceramic bearings for testing their potential use in US military aircraft, mainly helicopters, where they can operate at much higher temperatures and speeds than a steel bearing.
Without sufficient lubrication, conventional steel bearings in a military helicopter might last about 10 minutes; while a ceramic bearing would provide up to 30 hours of operation after loss of lubrication. Thus in a battlefield situation where an aircraft’s lubrication system is damaged, ceramic bearings would provide ample time for the craft to safely return to a secure area for repairs. Plus, ceramic bearings are lighter and help reduce aircraft weight.
“We aren’t a production house,” said Richard Roberts, director of corporate development at Reliance Tool & Manufacturing. “A big order for us is 100 pieces, with most job volumes at one or two pieces. Our true forte is conducting research and developing machining processes and systems for customers, and currently our biggest customers are private Tier I suppliers to the aerospace and defense segments.”
Reliance was established in 1948, and at that time, the company was manufacturing mostly stamping dies and rubber molds for producing oil seals. Then, in an effort to reduce part-processing time, the shop perfected hard machining techniques for its metal components in the Rc 58–62 hardness range and measuring in size from 0.875 to 20" (22–508 mm) in diameter or 2 to 36" (51–914-mm) square. Typical part tolerances are around 0.0005" (0.013 mm).
Key elements in Reliance’s efforts to develop cost-effective machining processes for ceramics are special cutting inserts developed by Seco Tools Inc. (Troy, MI), innovative use of a laser mounted on an Integrex i 200-IV ST Multi-Tasking machine from Mazak Corp. (Florence, KY), and research done in conjunction with Northern Illinois University. So far, the shop has successfully turned, milled and threaded ceramic materials such as silicon nitride, zirconium and alumina. Most significantly, the shop has reduced processing times for these materials by as much as 70% in some instances, while also creating parts that were previously impossible to produce.
For example, Reliance threads silicon-nitride tubing on its special machining system. Threading ceramics is a first and will pave the way for potentially incorporating ceramic piping for use in ultra-harsh environments. Additionally, engine components such as ceramic cylinder liners, glow plugs, and other components, can now be machined more efficiently with the Reliance system. Ceramic cylinder liners are practically impervious to grit and sand in an engine, saving downtime and expensive engine block replacement.
Reliance’s achievements in machining ceramics stem from the shop’s pioneering work in hard turning heat-treated tool steels in an effort to eliminate the costly and time-consuming secondary finishing operation of diamond wheel grinding. Over 20 years ago, Reliance developed cutting techniques and determined the best tooling for the hard machining process.
For hard turning, Reliance used custom cutting inserts made from cubic boron nitride (CBN) that worked well, but then the shop advanced into using ceramic tooling, which worked even better and was more economical than CBN. However, ceramic tools could not be used to machine ceramics, so the shop’s initial testing in ceramics machining involved the use of CBN cutters, but with the added element of heat.
“When the question of machining ceramics came up, we began investigating the use of heat to improve the process,” said Jeff Staes, director of technical services at Reliance Tool. “First, we used an acetylene torch to heat the ceramic material prior to machining it, but we needed a lot more heat than the torch could produce and a way to pinpoint exactly where the heat would be applied on the material/workpiece. This was where a laser entered the equation.”
According to Staes, the positioning of the laser beam in relation to the cutting tool is critical in the process. The laser must be pinpointed in an exact area just ahead of the cutting insert to, in a sense, preheat/soften the material to a plasticized state so it can be easily cut. However, he warned that there is a finite heating level, and precise temperatures must be consistently maintained or the material could be damaged.
The process uses a 300-W laser with a built-in sensor that also incorporates a secondary laser to measure part surface temperature. A vacuum system extracts the dust/chips that result from the process and could interfere with the laser’s beam.
While CBN tooling worked in the beginning stages of developing the ceramic machining system, Staes said that insert life was quite short, so the shop decided to try polycrystalline diamond (PCD) inserts from Seco. The shop, working closely with Seco, developed special edge parameters for these inserts that boosted cutter life well beyond that of CBN.
Seco’s PCD 30M multi-micrograin inserts, which were new at the onset of Reliance’s research, are used for the ceramic machining system. The inserts incorporate two different grain sizes, as opposed to just one. For the PCD 30M inserts, grain sizes are 30 and 2 μm. In combination, they provide levels of both toughness and wear-resistance unlike any other PCD grade, CBN or carbide insert.
Michael Shea, technical specialist at Seco, said the development of the PCD 30M technology was the first time the cutting tool provider combined grain sizes inside an insert’s tip.
Seco engineers from the company’s manufacturing headquarters in Sweden and from its North American headquarters in Troy, MI, travelled to Reliance and worked with the shop in testing the cutters. Seco mocked-up inserts specifically for this purpose, providing Reliance with different edge preps and lead angles to test. However, the basic standard PCD 30M geometry proved the most effective running with the laser and on ceramics.
Reliance’s ceramic system requires a high-accuracy machine tool and one that allows for the laser head to be easily mounted and precisely positioned ahead of the cutting insert. To fulfill these requirements, the shop’s Integrex i 200-IV ST Multi-Tasking Machine is equipped with twin turning spindles as well as an upper and lower turret. The machine’s configuration provides the flexibility for various types of machining and for adapting the different fixturing needed to mount the laser head.
Currently, Reliance is getting about 30 minutes of cut time per PCD 30M insert edge when taking a 0.040-ipr (1 mm/rev) depth-of-cut for a 6" (152-mm) long cut. Prior to incorporating the laser system, the insert edge would have failed instantly on making contact with the ceramic material. Reliance developed its own cutting parameters as far as speeds and feeds. As for the laser, positioning and heat levels are the proprietary specifications of Reliance’s ceramic machining system.
“Basically, we went from a zero ceramic cutting capability to 30 minutes with the Seco inserts,” said Staes. “And while that amount of machining time may not seem like much, as compared to the extensive time and cost involved with diamond wheel grinding, it is a very significant accomplishment.” ME
For more information from Mazak Corp., go to
www.mazakusa.com, or phone 859-342-1700; from
Seco Tools Inc., go to www.secotools.com/us,
or phone 248-528-5200.
Aerospace Shop Gets Five-Axis CAM Boost
Blue Force Technologies Inc. (Morrisville, NC) opened its doors in 2011 with a mission to provide specialized composites manufacturing services to customers who need access to high levels of engineering and manufacturing expertise with a fast turnaround time. The AS9100C-certified aerospace structure design and development shop specializes in helping large companies develop efficient composite manufacturing processes, and providing smaller companies with structures that they would not be able to take on themselves. Typical assignments include component design and manufacturing for commercial aerospace, military aviation, unmanned aerial vehicles, and military vehicles.
Soon the company was presented with an unanticipated problem, or as President Scott Bledsoe would rather say, an opportunity. The original Blue Force business model called for subcontracting tooling for composites manufacturing from qualified local shops. However, frequent design changes from customers, along with the need to produce tooling rapidly for urgent projects, was making it difficult to meet aggressive delivery requests that Blue Force wanted to accommodate.
Bledsoe had assembled a lean team of engineers and technicians with deep experience in component design and manufacturing for commercial aerospace, military aviation, unmanned aerial vehicles, military ground vehicles and complete aircraft prototyping. “Blue Force” was incorporated into the name because many in the company’s target markets would recognize it as a term denoting friendly forces that can be mobilized quickly to overcome imminent obstacles.
As a result of immediate customer response, the company decided to acquire its own CNC manufacturing equipment to incorporate CNC machining of foam tooling board, aluminum, and cured composites into its fabricating processes. In February 2012, it took delivery of a CMS Ares 4818 five-axis machining center from CMS North America Inc. (Caledonia, MI) with a large 15.8 × 5.9 × 3.9' (4.8 × 1.8 × 1.2 m) work envelope. The midsized moving bridge machining center is designed for machining small to midsized workpieces made from light alloys, composite materials, reinforced plastics, tooling board and wood.
Like everything else in this fast-paced industry, Blue Force needed to get up to speed with its CNC manufacturing capability as quickly as possible. It selected Mastercam X6 Mill Level 3 and Multi-Axis software from Mastercam/CNC Software Inc. (Tolland, CT) to enable it to substantially reduce tool manufacturing leadtimes and project delivery cycles. The conventional approach would have been to hire an experienced Mastercam programmer and train him or her in the intricacies of composite tool manufacturing. Blue Force decided to go in an entirely different direction by making Mastercam programming the responsibility of its highly experienced design engineer, Blain Echols.
“Customers like us because we are fast. But our tool development process was like a duck’s feet under the water,” said Bledsoe. “From what the customer saw, we were pretty fast and smooth. When we looked under the water, we were always frantically trying to move tooling blocks around to get people to machine them. Inevitably, you can’t communicate with a guy two hours away as well as you can with someone who is 20 feet away at the machine. Little details would get lost. Our tooling would come back missing a scribe line or something. Or a customer would throw a late change at us. We realized that there was an opportunity for us to shorten our cycle even more, which is what people really want to pay us for.”
“Blain is a talented structural designer who is proficient in both CATIA and SolidWorks. We thought it would be far easier for him to learn and become efficient in programming our new CNC equipment than to teach an experienced Mastercam programmer everything he would have to know about the art of composites manufacturing. Blain already knew what the end product needed to look like. He just had to learn how to interface with the machine using Mastercam,” said Bledsoe.
Blain received initial help from its Mastercam Reseller, Barefoot CNC (Morganton, NC), in terms of a three-day, five-axis training course along with as-needed technical support, in person, over the phone and via the internet. “With this help, Blain went from zero knowledge in March to doing some pretty fancy five-axis machining in a matter of a few months. By May, we were shipping production tooling manufactured on our own equipment to a company in California,” said Bledsoe.
Blain estimates that he spends a third to a half of his day using Mastercam. These days he only calls Barefoot CNC for pointers about once a month. Some of the most helpful things he has learned include how Mastercam simulation features, Backplot and Verify, allow automatic visualization of toolpaths to make sure they are interference free and for assuring that material removal is exact. He uses these features for nearly every part so that he can machine it right the first time, reducing rework and scrap, which may be a considerable cost when you consider that a large block of structural foam can cost as much as $5000.
Overlaying new geometry function makes it possible to revise an existing program to accommodate design changes without having to reprogram an entirely new part.
2-D Toolpaths + 3-D Positioning allows Blain to present the tool to the part at the most advantageous angle for difficult to access features while using the shortest possible tool for optimal rigidity. Being able to readily adapt presentation of the tool makes it possible to machine very tall workpieces within his machine’s 4' (1.2-m) Z axis. When Blue Force isn’t using the full table of the CNC machining center for a single part, it can create programs that allow three or four different projects to be staged on the machine at the same time.
The addition of five-axis CNC machining has improved the spectrum of value Blue Force offers its customers. For example, the company can do post-machining of composite tools to further tighten up tolerances on critical surfaces. This is something the company would never do if it were outsourcing its machining.
“In aerospace everything is about risk reduction,” Bledsoe said. “The only way to get to risk reduction is to build something and test it. The faster we can get out these parts and tools into our customers hands for testing, the more cost-effective our customers can be. Fast turns save our customers a ton of money.”
Recently, an aerospace customer wanted to convert a legacy metallic structure to composite. They had ideas on how they wanted to do it and they needed to demonstrate it. They sent Blue Force Technologies bare bones information about what they wanted to do and Blue Force jumped into its development process, creating several parts each with different tools so its customer could evaluate them. But Blue Force did more than just ship the customer some parts.
“There are a lot of small shops out there that can build things quickly, but we are very good at knowing what we built, Bledsoe said. “When we build something and our customer likes it, we can tell them what was different about it from other parts so they are better able to implement these ideas in their own plant. We can do this because we maintain tight control of our own manufacturing processes.”
It seems that aerospace customers like Blue Force Technologies products and services a lot. The company’s orders have quadrupled in the past 12 months. ME
For more information from Mastercam/CNC Software Inc., go to www.mastercam.com, or
phone 860-875-5006; from CMS North America Inc., go to www.smsna.com, or phone 800-881-0574.
Shaping Tool Management Today
Shape Corp. (Grand Haven, MI) is a supplier to global automakers who depend upon Shape and its sister company NetShapes to design, develop and produce cutting-edge energy management components to meet required regulations and standards. Energy management systems are components that work together to manage energy during an impact, protecting passengers while reducing damage to the vehicle. Products consist of high-energy efficiency bumpers and bumper energy absorbers for passenger vehicles and light trucks, pedestrian impact energy absorber systems, lightweight bumper beams and energy management modules that integrate impact and other structural functionalities into a single finished part.
“We pride ourselves on listening to client pain points–and then developing customized, cost-effective solutions that enable them to be significantly more productive and profitable,” said Wes Griffes, group leader-process improvement and a 16-year veteran of the company that also specializes in advanced roll-forming expertise.
“From concept through design, in-house testing in our lab, and final production, we can develop a single part or a complex assembly. But we also knew we could improve our efficiencies with more attention paid to our tool management activities,” said Griffes. The company decided that it needed some management support of its own to take its reputation for making exceptional products and delivering them on-time to the next level.
Prior to 2009, Shape used cabinets to house and keep track of its tool usage in the firm’s toolroom during the manufacture of bumpers, pedestrian bars, which prevent pedestrians from being thrown under a vehicle if struck by that vehicle, and various other products. Shape-NetShape provides ultra-high-strength steel and injection-molded bumper systems.
Griffes and his superiors, however, never truly had an accurate read on tool consumption, either for parts produced or materials machined on Shape’s six Bridgeport mills, Haas and Mazak CNC units, four grinders, and various drill presses, cut-off saws, and other lathes. Materials that are machined include primarily A2, D2, M2, 4140, prehardened, and cold-rolled steels; plus plastics and nylon.
“We knew a vending machine would be a wise investment because we had heard how much time and money had been saved by others with similar tool-tracking issues,” said Griffes. Shape, which has been a multiple winner of General Motors’ coveted Supplier-of-the-Year award, requested demonstrations and quotes from leading vending providers, and after a lengthy review process made its choice.
“We went with MSC Industrial Supply (Melville, NY) because their dispenser was so easy to learn and operate. It’s simply intuitive in so many ways, including its automatic tool-reorder feature and its ability to limit access to certain costly tools to only those who actually require those tools,” said Griffes. But there was more to the MSC package than just a new piece of tool-repository equipment.
“Installation and implementation were painless because there was extensive pre-planning by both companies,” said Griffes. “MSC was with us every step of the way to fully train us and to ensure that ideal transfer of what was within our cabinets into our new single-bay machine, and our high-dollar items were given priority space.”
Overall savings came quickly. “Within nine months, we realized a reduction of $55,000 in disposable tool costs. This was a direct result of our dispenser that showed me, in its highly detailed daily reports, exactly who took what to do what and our total tooling cost. These documents also proved that we had been so focused on not running out of key tools that we simply over-ordered on most occasions creating excess inventory and the need for someone to regularly supervise our toolroom,” said Griffes.
But Shape did more than improve its bottom line. It enhanced its workforce, too. After seeing the reports that showed how much tooling was actually needed versus what was thought to be needed at any given point, Griffes began to use the vending dispenser as a training tool for shop leaders to teach machine operators how to produce their work more efficiently.
“We showed our machinists how the vending unit was a drastic improvement over our previous tool-replenishment methods and how it helped make everyone constantly aware of our corporate goal to run a leaner plant,” said Griffes. “Since the MSC vending machine has literally become my eyes of tool management, I now have far more time to do other more pressing duties throughout our shop,” said Griffes. “For example, I can more closely identify and track other training opportunities, including those in some of our other facilities.”
Support for the vending service from MSC has been “exceptional,” said Griffes. “MSC assigned us a vending specialist, Matt Dutkiewicz, who works closely with our local MSC rep, Lola Brophy. This tandem regularly visits together to ensure our machine is functioning as expected and that the tooling drawers are loaded with the best MSC brands that will deliver optimum performance for whatever it is we are set to machine.”
The result is that Shape delivers on-time, cost-effective, custom solutions to its customers, and MSC is credited through its vending dispenser and vast toolbox of metalworking brands with providing the exact same value and support to Shape Corp. ME
For more information from MSC Industrial Supply Co., go to www.mscdirect.com, or phone 516-812-1484.
Five-Axis Design for Demanding Applications
When Moore Tool Co. (Bridgeport, CT) set out to build a true five-axis, high-speed machining center for use in the production of critical components for the most demanding industrial applications, the challenges were many. The machine was targeted to serve critical needs in the turbo machinery, mold and die, scroll compressor and medical markets. In particular, this new equipment was needed to produce a wide variety of precision aerospace components such as blisks (bladed disks) and IBRs (integrally bladed rotors), plus impellers and other complex contoured parts.
Machine design criteria required that the machining center have the capability to provide superior high-speed five-axis machining when milling materials ranging from aluminum to hardened steel and titanium. The machine needed 30,000–40,000-rpm high-speed cutting capability, dynamic response, superior stability, on-board cooling, vibration damping and automation adaptability. In addition it had to present a user-friendly Windows working environment with substantial on-board memory in a CNC without external devices for downloading complex programs and, above all, high precision.
However, when the company was founded by a man, Richard Moore, who is credited with “adding a decimal place to the precision of the machining industry,” that last requirement is practically a given. Moore took a “from the ground up” approach in developing its five-sided precision (FSP) line of machining centers. They reviewed all the cutting parameters of their prime markets. Speed and accuracy were considered carefully when evaluating the needs of working in different materials along with the differing requirements of production and part accuracy. After all, the requirements of machining aluminum and titanium with high production rates can differ when compared to the intricate contours and features of mold components produced directly in hardened steel. When you add in requirements for efficient graphite machining, the challenges are quite significant.
The need for a combination of high-precision and high material removal rates was obvious. Plus, the complex contour surface profiling on leading and trailing edges of blades and especially blisks and IBRs, where pocket profiling is most challenging, made a high-speed processor essential to maintain acceptable feed rates. The machine configuration, especially as it relates to the position and configuration of the rotary tables and spindle, would be a key to both the high production and precision needs of Moore’s customers.
The FSP300X five-axis machining center became the showcase member of this line, bringing together all of the designs elements required for its precision machining requirements. The FSP300X has acceleration to 1.7 G in five-axis mode and features 24 and 44-position toolchangers with laser toolsetter, precision spindle with HSK40E taper and a Siemens Sinumerik 840D CNC to handle all the particular needs of its key markets for precision component manufacture in a high-production environment. Plus, the FSP300X offers the flexibility to perform highly complex operations on one-off runs at a cost competitive level.
In order to achieve the maximum machine performance, Siemens performed a detailed dynamic analysis of the complete machine, control and servodrive system with its Mechatronics service. Data gathered during the Mechatronics process is used to optimize the complete machine concept, allowing the machine builder to push their machine designs to the absolute performance limits with predictable accuracy and part finish results.
In highly complex blade contour and finishing operations, the Siemens Sinumerik 840D CNC provides an advanced aerospace-specific software feature, COMPCAD, by which the control’s compressor function smooths point-to-point programming. The real benefit of the control is realized when processing the part using NURBS (Non-Rational Uniform B-Splines), which takes the machine to the most advanced level of smooth contouring and chatter elimination. This is achieved by using splines in an axis-specific tolerance window. Contour violations are thus avoided, plus the efficiency of acceleration/deceleration curves is increased, while slowdowns/speed-ups at block transitions are eliminated. These are absolutely critical factors in the machining of aerospace surfaces.
In programming, according to Moore engineers, the open architecture of the CNC, along with its high-speed, user-defined macros and flexible block search capabilities, made it an ideal choice for the FSP300X. The ability of the 840D to handle very large programs typical for intricate mold-and-die applications without “drip feed” was also of utmost importance.
Options for heightened aerospace, mold and die, medical and other high-precision uses of this machine include high-frequency spindle options up to 80,000 rpm; a variety of robotic part loaders all designed and built by Moore Tool with all control parameters incorporated onto the host CNC; a graphite machining package; laser toolsetter with measurement and compensation standards, plus other custom configurations.
Moore Tool further enhances the machine dynamics on its FSP300X by use of Siemens Simodrive 611D drive packages. Other features of the FSP300X include XYZ travels of 420 × 320 × 310 mm, B-axis travel of 230°, infinite C-axis travel, a table load capacity of 25 kg and maximum swing (C-axis rotary) of 300 mm. Standard features includes a 10-kW spindle power and 20 m/min contouring federate. The machine delivers geometric straightness on the XYZ axes of 0.005 mm and geometric squareness on the XY/XZ/YZ axes of 0.0076 mm.
Moore Tool, which is a member of the PMT Group, designs, engineers and builds its machines, in conjunction with sister company, Producto, in a 200,000 ft2 (18,581-m2) facility with approximately 200 employees. Moore Tool is a member of The PMT Group. ME
For more information from Moore Tool, go to www.mooretool.com, or phone 203-366-3224; for more information from Siemens Industry Inc., go to www.usa.siemens.com/cnc, or phone 847-640-1595.
This article was first published in the March 2013 edition of Manufacturing Engineering magazine. Click here for PDF.