OpenHealth, one of the world’s leading providers of business and technical solutions to the dental healthcare industries, was formed by the owners of five major international dental lab groups—Aurum, Cordent, DTS, Race, and ZMC. Under the brand name of Core3D Centres, they combined to offer their respective lab and milling center services to labs, dentists, and educational institutions in 15 countries on three continents.
Core3D provides dental labs with new materials and new products through advanced manufacturing techniques—including robotic ultrasonics and conventional machine tools—that enable them to supply product, usually with 24-hr turnaround, while achieving near 24/7 untended operation and more than 15% reduction in scrap material on very expensive substrates.
OpenHealth’s Las Vegas-based Core3D facility, where Tim McKimson is worldwide director of engineering, is located near the prestigious Las Vegas Institute for Advanced Dental Studies (LVI), where restorative and cosmetic dental techniques are taught to practicing dentists and lab technicians. Here, Core3D provides a full range of CAD/CAM/CNC machining and finishing services to LVI and dental labs across the US.
Led by technical operators Mark Ferguson, Danny Palomares, and Drew Hrubes, the Core3D team prepares CAD files developed from data typically gathered with an iTero oral scanning wand, or from CAD files from scans of conventional dental impressions from the patient’s mouth. Files are then digitally captured in a dental scanner made by a company such as 3shape. CADENT and other software are typically used to image the impression and begin the process of creating the crown, bridge, abutment, coping, implant, or even full denture restoration, as required by the individual lab. 3D CADENT files are G-coded at a remote location of the parent company for transfer to the CNC machine tools at the various Core3D facilities worldwide.
The next step is translation of the digital impression to a mold, using conventional machine tools. In most cases, the required structures are designed simultaneously, then the mold with coping is introduced to a DMG Sauer ultrasonic dental machine made by DMG / Mori Seiki USA (Hoffman Estates, IL) for preparation of the final structures. This is where the most advanced substrates are processed, ranging from conventional, yet difficult-to-machine metals such as titanium and cobalt chrome, to the newest advanced materials, including glass ceramics, lithium disilicate, and zirconia. These substrates are quite expensive and require extreme care in their handling and processing to reduce scrap and control operating costs.
McKimson explains that the decision to cut with ultrasonic technology was relatively easy, given the inherent wear conditions and high cost of conventional tooling. In the ultrasonic process, a combination of electrolysis and fluid lubrication act in concert to create an ionic attraction of particles, removing material in a highly predictable and accurate manner, without the mechanical stress implicit in conventional machining techniques. As a result, the surface of even the hardest materials can be machined with the tactile smoothness required for dental implants.
The DMG Sauer ultrasonic machines located at this Las Vegas facility, fully operated by Sinumerik 840D sl CNC technology from Siemens Industry Inc., are loaded with blanks of material into a 66-position feeder station, then delivered into the cutting theater by a Motoman robotic arm equipped with Schunk pressure grippers. The Sinumerik 840D sl recognizes the code on each workpiece pallet, and each job is identified by the patient’s name to minimize the risk of error in work-product delivery. As McKimson further notes in detailing the accuracy of the ultrasonic machining technique, each tool used is obtained from the 25-position toolchanger, and its position is monitored by an integral Renishaw probe. The technicians often load three sets of the tools needed for the 66-piece runs, ensuring virtually 24/7 untended operation of the machines. Through the capability of the Siemens CNC, a remote alarm can be sent when tool breakage or some other off-normal condition occurs during production.
The extremely hard materials being machined are produced with accuracies in the 2–4-µm range, owing to the combination of ultrasonic technology and the high precision of the Sinumerik CNC, according to McKimson, who notes the reliability of this accuracy has been a significant help in reducing scrap at Core3D.
In another area of the facility, conventional mills are used to make polyurethane models. Wieland Zeno 4820 and 4030 minimilling machines are also utilized for the production of various crowns, wax/resin forms and models, veneers, inlays, and implant abutments.
As evidence of the decidedly international nature of this emerging dental giant, all the zirconia and lithium disilicate materials are provided in the IPS e.max System from Ivoclar Vivadent, a company based in Liechtenstein. The company has branches in the US and Canada, which supply the Core3D Centres in those countries. The templates and cutting tools are closely controlled and validated by the manufacturer to ensure that the preparation of these materials in dental applications is properly executed.
McKimson notes that it was the DMG Sauer machine builder who recommended the Siemens control. "They knew we were dental technicians and engineers, not machinists, by nature. The Siemens control has been extremely easy to use and our training time from the builder was minimal. Troubleshooting is mostly done by our operators, with only occasional assistance from Siemens." Danny Palomares, one of the technical operators, agrees. "My training is in the dental lab world, not on machine tools. It was a great relief to have such a sophisticated control that operates with relatively simple language commands and cycle adjustments."
Palomares is also responsible for the translation of the lab’s incoming data files, so he is involved from start-to-finish with most of the projects done at this Core3D facility. In a single day, for example, he might use Delcam DentCAD, then hyperDENT CAM software, all translating the cutting paths from the dentist’s impression to the Siemens CNC on the DMG ultrasonic machines in this facility. As McKimson adds, "The sub-routines on the Sinumerik CNC make our job much easier to accomplish and faster to complete. Plus, when you add the upside of at least 15% reduction in the scrap that we’ve realized with the ultrasonics, it’s a real win-win situation for us."
While there are substantial differences between European and American dental labs in terms of the materials and assembly techniques used, and despite the fact that literally all projects are highly customized based on the individual needs of the patients and the preferences of the labs and those of the dentists performing the procedures, in the end, the typical project is being turned in 24 hr or less.
For Core3D Centres, using best-in-class equipment is critical. McKimson points out the "know-how" provided through their CAM-DO committee. This global technical committee conducts regular on-line meetings to discuss what’s working and what’s not in their various worldwide operations, and then optimizes and standardizes the processes. He recalls one unanimous vote of approval was voiced on the performance of the DMG Sauer ultrasonic machines with Siemens controls. Core3D currently has nine such machines in their network, all used to process the most advanced materials. ME
For more information on Siemens Industry Inc. Drive Technologies—Motion Control, go to www.usa.siemens.com/cnc, or phone 847-640-1595.
Laser Automation Builds Truck Beds
Visitors to Bradford Built (Washington, KS), a company that manufactures specialty beds for pickup trucks, are often surprised at the amount of automation in use at the metal-fabricating facility. Brad Portenier, co-owner of Bradford Built with his wife Donna, has incorporated automation wherever possible to streamline operations and increase production.
The location of the facility in a 1000-square mile (2589 km²) county with a population of less than 6000 people serves as a driving force behind its lean manufacturing approach. Bradford Built doesn’t have a huge labor pool to draw from, and must meet production goals with the people available to it. Automated systems and robotics enable the shop to meet order delivery times without additional labor, and eases the physical demands of heavy lifting for its employees. In addition to manufacturing all types of truck beds, boxes, and trailers, the company also provides welding and metal-fabrication services for repairs and component production.
The most recent automated system installed at Bradford Built is a HyperGear flying-optics laser-cutting flexible manufacturing system (FMS) from Mazak Optonics Corp. (Elgin, IL). This fully automated system basically runs untended and pumps out work at production levels greater than the combined output of four previously used laser systems.
With 45 employees, Bradford Built produces four different truck-bed styles in multiple sizes for each model. The shop works with a large amount of 7, 11, and 14-gage material and 0.125" (3.18-mm) thick tread deck plate, processing millions of pounds of material annually. Manufacturing operations at the shop include laser cutting, robotic welding, press brake bending using a robot load/unload, and CNC machining.
The shop produces about 20 beds a day with the production goal of completing jobs as quickly as possible. At any given time, there can be at least 200 completed truck beds in inventory, but they don’t stay there long, because the majority of them are usually already sold.
Raw sheetmetal, mostly 5 x 10' (1.5 x 3-m) sheets, enters the shop and moves directly into the laser FMS stocker. All bed-manufacturing operations depend on the laser process. Bradford Built doesn’t use extrusions or rollings, but instead builds everything it needs for the beds. Originally, Bradford Built would plasma-cut raw sheet material for production preparations. However, it was impossible to consistently generate perfectly round, accurately positioned holes for assembly of mating parts, or holes that could be used for self-tapping screws. For these reasons, the shop turned to laser cutting.
From the laser, parts move to a robotic press-brake operation. Parts are then restocked and are ready to move to assembly lines. Four or five workers assemble products with the help of automated welding systems. Once beds are fabricated, chips and burrs are removed, and the components are washed and powder-coated.
The shop first installed one hybrid-style 2-D Mazak Optonics Super Turbo-X MK II series laser system, which cured all of the hole problems associated with plasma cutting. When production levels increased, however, the shop had a difficult time keeping up with the higher production demands with only one laser system.
According to Portenier, the good news was that, for the first time in the shop’s history, it was producing perfectly round holes and cutting at better overall accuracies with the Mazak laser system. To keep up with production, Bradford Built added four more Super Turbo-X MK II laser-cutting systems from Mazak Optonics. Four of the lasers were part of an FMS, and one was kept as a standalone used for custom jobs. Unfortunately, the shop would often have to tab thin parts to keep them from moving, and would have to reduce rapid-traverse speeds when moving from one cut to the next.
In the fall of 2010, Bradford Built made a significant investment in its laser-cutting processes. Going beyond its older standard mid-range machines, the shop incorporated the latest in laser-cutting technology. It acquired a fast, linear-motor-driven, fully automated Mazak HyperGear laser-cutting FMS. The 2-D flying optics laser cutting system, with a two-pallet changer, features full hybrid linear motors in all five machine axes for 3g acceleration, high-speed cutting, and superior positioning accuracy.
The HyperGear positions at accuracies of ±0.0004"/19.7" (0.01/500.4 mm) in X and Y axes and ±0.0004"/3.94" (0.01/100 mm) in the Z axis. Repeatability for all three axes is ±0.0002" (0.005 mm).
"We ramped up our rapid-traverse capability to 5000 ipm [127 m/min] with the HyperGear," says Portenier. "And what is even more impressive is that the one machine puts out the same amount of work that we were getting out of our four older standard, mid-range systems combined, and in a shorter amount of time."
Bradford Built ran its four standard model FMSs during day shifts, while the new flying optics FMS worked practically 24/7 at the shop. Eventually, the new system opened up a lot of shop-floor real estate for Portenier. He was able to sell four of the five older systems, retaining one with load/unload automation for working on custom orders.
A 10-drawer FMS feeds the HyperGear system. The FMS accommodates all of the different materials, material thicknesses, and sheet dimensions that the shop runs, and features a series of intelligent functions that accelerate machine performance.
"The one thing that really drew us to Mazak Optonics was its automation. On the HyperGear, we opted for all the extra automation, such as Mazak Optonics’ Intelligent Torch Changer and Intelligent Nozzle Changer, which lets us automatically change laser nozzles and torches. We also added a nitrogen generator to eliminate any oxide layers on cut edges," says Portenier.
Mazak Optonics’ approach to laser system safety allows Porenier to run the HyperGear practically untended in lights-out operation with no risk of injuries. Instead of safety curtains and pressure-sensitive pads, Mazak Optonics uses caging and redundant switches that are extremely difficult to bypass.
"Higher-end technology and automation are making their way into fabrication shops. There will always be the repair shops where the need for this equipment really doesn’t apply, but in my opinion, shops that embrace technology and automation will be the ones that continue to advance and be profitable," comments Portenier.
Another significant advantage of the HyperGear for Bradford Built is that it can run material unclamped, because the machine’s laser moves instead of its worktable. This is a critical factor in how the shop runs material. Rather than cutting deck-plate material tread-side up, the shop cuts it tread-side down, so that it can use automated material-handling systems with suction cups to move parts from the laser to press brakes. This capability, according to Portenier, required only a small amount of software work on the part of Mazak Optonics engineers.
Bradford Built gets about 87% sheet-material utilization, and the HyperGear laser-cutting FMS, along with automation, plays a key role in accomplishing that.
"We hope to bury the HyperGear in so much work that we’ll have to add another one," says Portenier. And he sees that happening in the very near future if business continues to grow at its current pace. ME
For more information on Mazak Optonics Corp. go to www.mazakusa.com, or phone 847-252-4500.
a Shop’s Business
When Cast Technologies (Peoria, IL) opened its doors over 120 years ago, the foundry and machine shop was in the business of making various brass plumbing products. Currently working on its fifth generation as a family owned-and-operated business, Cast Technologies has repeatedly moved with the times and adopted the latest technology to remain competitive.
From its earliest days, machining had always been part of Cast Technologies’ manufacturing process, starting operations with just two steam-powered VMCs and later one CNC machine. Today, the company employs about 150, primarily machining aluminum and brass components for diesel engine, transmission, and earth-moving applications. Components include air-intake elbows, turbos, bearing carriers, oil pans, and housings for diverse industry applications, including construction and agricultural equipment.
As the economy took a turn for the worse a few years ago, the operators and owners of Cast Technologies were feeling market pressure for better productivity, quality and flexibility, shorter lead-times and competitive part costs, the management knew they would need to do something to stay competitive, particularly as they watched the pool of skilled machine operators dwindle over time.
"As we started to look for ways to improve our business, one equipment innovation, the potential of automation, in particular, caught our eye," says Tim Sommer, machine shop plant manager. As a result, in 2008 Cast Technologies incorporated mixed part-type automation capability into its machining process by installing an enhanced pallet-management system, the Makino Machining Complex (MMC2), with three a61 HMCs from Makino (Mason, OH). The machining cell consists of 40 pallets and three Makino a61 HMCs, designed for automated and cellular manufacturing applications that require maximum throughput and reliability. The MMC2 is capable of running multiple jobs concurrently and doing the work of six stand-alone HMCs.
"We did our homework, running simulation after simulation. In the end, we simply couldn’t argue with the cost versus benefit of the system," explains President Clay Canterbury. "Automated systems inherently work harder than standalones, and therefore undergo additional stresses. If an automated system were to go down, it would be the equivalent of six standalones going down at the same time, and this is simply not an option for us," explains Canterbury. "Given the nature of these systems and the need for little to no downtime, it was critical to choose the right machine manufacturer. Our research resulted in great confidence that Makino is the right partner for our business."
As a result of investment in the MMC2, Cast Technologies has seen firsthand the many benefits of automated systems, including reduced manufacturing costs and less need for manual intervention, improved quality and flexibility, and increased throughput. And, with expanded capacity and the economic advantages afforded by the flexible pallet automation system, they have chosen to use this fast, efficient system to quote new business and win new additional business.
"With the MMC2, we have been able to go from 12 operators to eight, which has minimized cost and streamlined our process," adds Sommer. "We were also able to then redeploy and reutilize the additional manpower, training them in our other important machining areas and increasing our overall success as a company." With a 33% reduction in labor, combined with the flexibility of smaller batch sizes resulting in reduced work in progress (WIP) and scrap, the benefits of the system affect the business on multiple levels.
One primary area of growth can be found in spindle and equipment utilization. Cast Technologies has seen a 25–30% improvement in spindle-utilization rates compared to their standalones, and management is expecting this rate to increase as they ramp up production rates and focus more heavily on their cellular technology. A key component to their increase in equipment utilization has been their ability to virtually eliminate setup time and increase efficiency by reducing part load/unload times, as well as part and tool changeover time.
"Our entire system was disrupted when we would start and stop a job on the standalones, sometimes taking a few hours to make changes," says Sommer. "This is not the case with the MMC2. Its setup takes only a few minutes, ultimately enhancing our process efficiencies." Operators can now load the castings, pull up the appropriate program for the job and let the automated system take it from there. Makino’s MAS-A5 Cell Controller works dynamically using priorities set for pallets, part programs, process sequences, and production orders, maximizing the utilization of the shop’s investment.
With the MMC2, Cast Technologies has also been able to increase their overall productivity, shortening their production lead-times and improving their competitive position in the marketplace. "In the past, we would receive eight-week lead times. In today’s manufacturing environment, our average lead times are typically down to four weeks or even less," explains Sommer. "The operational consolidation afforded by machining automation allows us to make quicker deliveries and meet these expedited customer needs."
The company is also reporting faster cut times, improved machine tool efficiency and production increases, and a significant reduction in cycle times compared to their stand-alone machines. "Without optimizing any programs, we have already seen a drastic reduction in cycle times since installing the MMC2," explains Supervisor Jeff Peters. "And by taking advantage of the full performance of Makino’s a61, we will be able to reduce our cycle times even further." With each a61 housing a 219-tool magazine (they average 10 tools used per part), they are currently running 100 different part numbers across their system. This ability to have a mix of product helps them to increase capacity and adapt quickly to customers’ order requirements and changes in part volume.
Cast Technologies has significantly reduced their supply of WIP and finished goods inventory. In the past, the company would run large economic order quantities, machine in advance for their customers, and house a substantial finished-goods inventory. If the specs of a part changed, the inventory would be rendered useless, creating a loss for their business. The previous approach also caused them to invest a large amount of time and money in surplus inventory that wasn’t yet needed, resulting in non-value-added machining time.
"For years, we had been stockpiling inventory to keep up with customer demands and shortened lead times," explains Sommer. "But building inventory has a number of pitfalls, and was costing us a significant amount of money. In using the MMC2, we quickly realized that there is a more efficient way to successfully manage shorter lead times." Cast Technologies now engages in just in-time (JIT) machining to better maintain inventory levels. They also have trucks going to the customer daily.
The Makino MMC2 has also afforded Cast Technologies additional flexibility in their operations, giving them the ability to produce parts very quickly. Being able to implement dynamic scheduling with the automated system’s MAS-A5 cell control software enables them to easily produce fast-priority changeovers by simply loading the raw stock, calling up the program, and then running the parts required. "If a customer calls because they have additional part needs the same day, we can establish a priority job in the system, verify that the tools needed are available in the program, run the part, and send it over to the customer in about an hour or two. Without the MMC2, we would have to tear down one of the stand-alone HMCs, go through setup for the job, and run multiple pieces, creating additional inventory and disrupting production of other jobs," says Sommer. "Now we can produce the parts on the same day."
Cast Technologies has also benefited from the additional control and timely information management capabilities that the a61 tool monitoring and Makino MAS-A5 software provide. With the Makino software, they are able to manage their machines, tools, fixtures, production schedule requirements, programs, and program changes. Its tool-resource management feature notifies the operator when required tools have exceeded their estimated life, and its tool-life monitoring function informs the operator of how many spare tools are required to finish the current project.
The software also offers efficient, single-point operation of multiple machines, orders, products and maintenance requirements, and provides system monitoring as well as historical data, trending, analysis, and tracking. With this software, Cast Technologies has been able to cut back on fixture upkeep and machine maintenance, all while saving on costs.
"Repeatability is extremely important to our business," says Sommer. "We don’t want our parts to run from one end of the spectrum to the other. We want them to be right down the middle each and every time, and the MMC2 and a61s help us to do that." Makino’s MAS-A5 software has the ability to implement the same work programs and offsets, following the job no matter which machine it goes to, allowing for identically produced parts on each machine without discrepancies. ME
For more information on Makino, go to www.makino.com, or phone 513-573-7200.
Laser Measuring Ensures
Jet Engine Quality
When your car develops engine problems, you simply pull over and wait for a mechanic to come and solve the problem. Not so if you’re flying at 30,000' (9144 m) and a jet engine fails, putting the lives of several hundred people at risk. That’s why the quality of aircraft engines is of critical importance to leading European aerospace engine manufacturer MTU Aero Engines (Munich, Germany).
"At MTU, we attach the highest priority to quality in manufacturing for all of our components," explains Walter Strohmeir, user-support representative for NC engineering with MTU Aero Engines. In addition to supporting machine operators with virtually every aspect of NC machining, his responsibilities include programming CNC routines, and procuring machines and the peripherals that go with them. "All of our engine components must satisfy the close tolerances which we specify—often to within just a few hundredths of a millimeter."
To meet the exacting production engineering demands of aero-engine manufacturing, MTU uses the LaserControl NT noncontact measuring system from Blum-Novotest (Gruenkraut, Germany; Erlanger, KY) to provide process stability in manufacturing aerospace engine components. MTU relies on the LaserControl NT optical measuring system for toolsetting and tool monitoring. The optical system provides basic tool-breakage detection and captures data including tool length, radius, wear, cutting-edge bursts, and spindle and tool-carrier accuracy at nominal spindle speed. The system also compensates for spindle displacement at high speed, and can detect and correct tool-clamping errors.
MTU Aero Engines first selected LaserControl NT back in the mid-'90s. After purchasing its first laser system, existing machines were gradually upgraded, and subsequently new machines were acquired with LaserControl NT already installed. Today, MTU Aero Engines has more than 100 Blum laser systems in use across the company. Around 300 to 350 MTU employees work with the system in three shifts. A number of machines are also equipped with Blum tactile touch probes for blisk measurement and automatic workpiece corrdinate setup.
The Blum systems are used to provide quality assurance for the manufacture of all MTU engines. They include the new GP7000 family of aero engines, which the company produces together with industry partners. MTU has responsibility for the low-pressure turbine, the intermediate turbine casings, and high-pressure turbine components. The GP7000 family of aero engines is used in the long-haul sector, including scheduled services of the Airbus A380 since August 2008. In its class, the GP7000 is a benchmark in terms of reliability, fuel consumption, and noise emissions.
A major role in aero-engine manufacturing is played by machining of blisks, a term that blends the words blade and disk. Blisks are designed to marry maximum performance to minimum weight. The process involves integral rotor construction in which disk and blade form a one-piece component, rendering blade roots and disk grooves superfluous. "The chief advantages of blisks are their substantial weight savings, increased service life, decrease in the number of components through higher stage loading, and the reduction in the amount of maintenance required. Most parts are made from titanium. For toolsetting and monitoring, we deploy LaserControl NT throughout the entire blisk production line," explains Heinz Baumgartner, blisk production team leader for the medium-pressure compressor for the TP400 engine program. He supervises virtually all of the machining operations that are involved in "blisking." Almost half of his team of 19 work with the Blum systems.
It takes between 15 and 60 hr to make one blisk workpiece, depending on the size of the component and the type of machining that is required. The parts are worth between 30,000 and 60,000 Euros. This makes the constant monitoring of the tools used to machine them vital. If there is a problem in the production process, because of a faulty, worn, or incorrectly fitted tool and the work is scrapped, things can quickly get very expensive. Each component can require the use of about ten different tools, from twist drills to expensive special-purpose tools. At MTU in Munich, there was the odd occasion when the wrong tool was fitted in error, resulting in substantial losses. With the laser, MTU management can now be confident that such mistakes can’t happen again.
The laser systems also maximize machine utilization. In modern production facilities like MTU where manning levels are low, there isn’t an operator on every machine all of the time. One operator is often responsible for several machining centers. Without a reliable monitoring system, if there is a problem with a tool it can take a long time for the fault to be found. The tool may be broken, it may be worn, or its cutting edge may have burst, ruining the surface of the component. This is particularly true on weekends when running machines untended is essential, because of the manufacturing costs of the products.
"Our ultimate goal of achieving the greatest possible machine utilization means working toward the industry standard of 5000 hr per year. The longer the machines run, the more we can keep costs down. This can only be achieved by working unmanned weekends," Baumgartner explains. MTU Aero Engines plans to take a different approach to tool breakage in the future, one in which the laser measuring system will again take center stage. What is proposed is to interpret the error message, a function built into the Blum measuring cycles, so that if the laser detects a broken tool, a sister tool will be fitted automatically. This degree of automation will further enhance machine utilization by keeping unnecessary stoppages to an absolute minimum.
In addition, most of the machines equipped with LaserControl NT no longer require devices for tool presetting. Some machining centers operate in parallel, but MTU’s objective is to dispense with tool presetters altogether in future, so when the machines are fitted with new tools, the laser will capture the tool data to the nearest µm directly on the machine. This will eliminate human error like keying errors and transposed numbers when operators manually enter tool data that have first been logged on the presetter. Measuring directly on the machine is, in any case, much more accurate, as the data are recorded in the actual clamping situation and at working speed. All kinds of tools are measured with the laser-measuring systems. The smallest has a diameter of just 1.2 mm, while the largest cutter head is currently 250 mm in diam.
The LaserControl NT technology has completely eliminated occasional problems previously caused by coolant. "On this basis, we can now theoretically move to the laser with the tool dripping with coolant, and it still works. Together with the tool cleaning jets, which were installed a few years ago, this solution represents a quantum leap in process reliability. The good direct contact, which we have established over the years with Blum, is a major contributing factor. The same goes for the custom cycle which Blum has written to allow special-purpose tools with their nonstandard profiles to be measured," says Strohmeir.
MTU has also been able to use LaserControl to help solve a problem that occurs in day-to-day practice. Because of the long operating hours, the machines can experience thermal growth—which can adversely affect machining quality. LaserControl compensates for this effect by calibrating between machining steps. This means that the thermal growth in the machine axes or spindle that is found by calibration is stored in the controller as an additive zero offset.
"For us, it’s the process reliability that LaserControl NT offers that is its most important feature. The excellent cooperation with Blum is another vital factor for our business, because they understand what we want and can deliver it quickly. They are always giving us useful hints, like how we can measure the tools even faster. Above all, however, the laser measuring systems give us the reliability and confidence we need for our machining processes," Strohmeier concludes. ME
For more information from Blum LMT, go to www.blumlmt.com,
or phone 859-344-6789.
MAG HMC Fast Tracks Rail Components
At one time, best known for its products that can slow railcars down, Wabtec Corp. (Wilmerding, PA) has put manufacturing operations at its Spartanburg, SC, Passenger Transit Div. plant on the fast track to improved productivity with a dual-pallet HMC for machining two-piece railcar drawbars. The machining center selected to meet the increased demand for its products was an HMC 1600 from MAG (Fond du Lac, WI).
Spartanburg with 350 employees is one of 50 Wabtec manufacturing plants worldwide with a total of 7000 employees. Wabtec was formed in 1999 with the merger of Westinghouse Air Brake (WABCO) and Motive Power Industries, a rebuilder of locomotives for US railroads since the early 1970s. WABCO traced its origins back nearly 140 years to George Westinghouse’s invention of the first straight air brake system that revolutionized the railroad industry. The company designs, manufactures, and assembles a broad range of passenger and freight railway equipment and related components, power generation, industrial, and off-highway equipment.
Wabtec’s Spartanburg Passenger Transit Div. plant manufactures products for virtually every major intercity passenger transit system in North America, as well as for OEMs, like Alstom, Bombardier, and Kawasaki. Product lines include pneumatic, hydraulic, and electro-pneumatic brake equipment, car couplers and current collectors, as well as a full range of high-performance electronic and pneumatic transit door mechanisms. The company recently received the IRIS (International Railway Industry Standard) certification from the Union of European Railway Industries, which is based on ISO 9001, adding railway-specific requirements.
When demand for its products increased, there was a need for greater productivity in the drawbar-machining operation in Spartanburg. Wabtec previously machined the 181 kg, mild-steel drawbars on a single-pallet horizontal spindle machine with limited reach, resulting in the need for another machine to cut features deep inside the parts.
"We identified setup reduction and machine speed as two areas of opportunity for improvement, and we found solutions to both with the dual-pallet MAG HMC 1600," explains Dale Simms, Passenger Transit Div. manufacturing engineer, "We were looking for a machine with long spindle extension that would allow us to eliminate a second machine and two hours of cycle time, which had been needed to cut hard-to-reach pads on these parts," says Simms. "So, before we purchased a new machine, we ran tests at MAG’s Fond du Lac [WI] plant with the spindle extended 10, 15 and 20" [254, 381, 508 mm]. The machine performed very well, and its twin-pallet design is inherently more productive."
The HMC 1600 features dual 1600 × 1250-mm pallets and 360,000-position contouring table, which allows Wabtec to machine the drawbars as a set. The machine’s hydrostatic table provides a rigid platform. The wormgear drive with clamp securely holds axis position, enabling precision four-axis machining of a variety of part geometries. Full Z-axis reach to 800 mm allows high-precision deep-cavity milling, using shorter, more rigid tools. MAG’s exclusive Z-axis thermal compensation software, standard on the live spindle, dynamically offsets spindle growth to maintain the ±0.0254-mm tolerance required on the drawbars.
The key factor in reducing cycle time is the HMC 1600’s 35 m/min rapid traverse rate. "It is remarkably fast for a large machine," Simms adds. Heavy-duty hardened and ground roller guideways enable high acc/dec rates and provide a wear life nearly 10× greater than ball-type ways. A 75-sec pallet-change and 15-sec tool change also improve cycle time. The machine’s 31.5" (800-mm) live-spindle reach has eliminated a second machine and setup. At the same time, the machine’s capacity has allowed engineers to add the third major component of the drawbar assembly, the yoke, on the pallet as well, freeing up another machine in the process.
Wabtec uses a wide variety of tools to produce the drawbars and other railway components, including thread mills, boring bars, and some customized tooling. "We have two 50-tool pallets set up in a 100-tool magazine for the drawbar work, and we bought an extra 50-tool cart for some of the smaller jobs we run on the machine," says Simms. The HMC 1600 is available with tool cassettes capable of carrying up to 300 tools with a maximum length of 650 mm, and weighing up to 40 kg. A chain magazine with a tool capacity of 50 kg is also available. Maximum tool diam is 125 mm in a full magazine, and 300 mm with an empty-adjacent position.
Wabtec’s HMC 1600 is equipped with Renishaw probes and software, used to align castings on the fixture and to conduct preliminary checks on part features, before all parts get final inspection on a CMM.
Productivity improvement has been significant. The dual-pallet HMC 1600 with long-reach live spindle has increased productivity 66% on the two-piece railcar drawbars. "Once we put the job on the MAG machining center, our production jumped from 4.5 parts per day to 7.5 parts per day," says Simms. "We realized a nice bonus, too, when we were able to add the third component of the assembly onto the pallet, which freed up another machine for other work." ME
For more information on MAG, go to: www.mag-ias.com,
or phone: 920-906-2860.
This article was first published in the May 2011 edition of Manufacturing Engineering magazine. Click here for PDF.