Solutions Come in Many Sizes and Shapes
Advanced technology helps when selecting machining centers and cells, but so does expert support
By Jim Lorincz
Manufacturers want to make parts and hit their schedules with a minimum of problems. Job shops, in particular, have their own need for a great deal of flexibility, enabling them to switch from one job to another with the minimum of wasted time. For medium volume, high mix production, manufacturers can benefit from the latest automation on multipallet single machines or in multiple machine cells. Five-axis machining centers are all the rage in the commercial airline manufacturing supply chain and medical device industry. Large energy, off highway, construction, ag, and mining equipment components fit nicely on the beds of large HMCs, vertical turning lathes and boring mills, or traveling in tightly scheduled automated FMS machining systems.
“It’s important to select the right machining technology,” said Tim Pearson, consultant and owner of Great Glen Solutions (Cleveland), “but don’t overspend on something that is too complex.” Pearson is an advocate of lean manufacturing and was its practitioner at a major health care manufacturer of Nuclear Medicine and CT devices. “Five-axis machining in the right application can provide an important competitive edge, and robots can run through the night, but the most critical factors are high quality and even flow. These decisive elements are facilitated by the process capability of the equipment, and the involvement of the working team, in order to create even flow through minimal setups and preventive maintenance.”
Technology Center Gathers Solutions Providers
Advanced machine technology can go a long way, but there are all those other ancillary areas where equally sophisticated products for fixturing, tooling, CAM programming, and gaging and measurement must be handled so as not to create unnecessary delay and downtime. “A recent technological advance at the company is the support that our Center for Multitasking & Manufacturing Excellence can provide our customers,” said Chuck Birkle, VP Marketing, Mazak Corp. (Florence, KY). “When we look at all the elements that a successful installation of one or more of our big e-vertical multitasking machines requires, for example, the role of the Mazak Technology Center facilitating communication among the various third-party technology providers is critical.”
Mazak calls these third-party suppliers, among many other things, of programming, CAD/CAM, tooling, workholding and quality monitoring devices, VIPs, or value-inspired partners. “Some of them have desks right here in our Technology Center to conduct business, shortening up the food chain going from challenge to solution,” said Birkle. “In general, our customers are trying to do more with less: reduced tools, fixtures and floorspace. If we can consolidate those processes and also have only one loading and unloading mechanism for multiple machines that becomes a big benefit. For example, in our Palletech automation, we start with a pallet clamping mechanism for one workholding surface and design it in common among different machine systems. This allows dissimilar machines to be included in the cell,” said Birkle. “As a result, a four-axis machine can do the roughing and semifinishing, sitting right next to a five-axis machine that does the finishing. Also, one machine may have tool reach and capacity advantages the machine right next to it doesn’t.”
Commercial Aircraft Spur Five-Axis Machine Demand
According to Scott Walker, president, Mitsui Seiki USA Inc. (Franklin Lakes, NJ), there is a big demand for trunnion machining centers in sizes from 1 and 2.5-m, especially for job shops looking for new business in the emerging aircraft market. “Just to meet the growing aircraft industry demand for metalcutting capacity, about 1000 new five-axis machining centers are required. The market is being driven by an estimated $4.8 trillion in new aircraft slated to be built between now and 2035,” said Walker.
“The other challenging area involves the new engine programs, like the GE LEAP, Pratt Whitney Gear Fan, and the Trent 1000. These engine programs require all new materials to burn hotter for fuel efficiency, and new spindle requirements for machining IBRs [integrally bladed rotors] and single blades, and to machine really difficult-to-machine materials like Ti Aluminides,” said Walker. “There’s a good replacement market for very high-tolerance machines in the 800–1500-mm-size range for manufacturing gear boxes and engine casings where there are enough machines to accommodate the market,” said Walker.
Strategies for making blades is going to change with one or two machines to handle all the operations, according to Walker. Technology required for machining blades like fan blades for the Boeing 777 will have to deal with an unusual combination of materials. “The big black fan blades for the 777 will be a composite prop with titanium leading and trailing edges able to withstand the impact of a bird. I’ve been asked to design bigger blade machines, one that can hold the single blade between centers and rotate it and go around the outside with a cutting tool. And if possible I can also do the root work and the tip work in that platform machine, or in a subsequent operation.”
Additive Technology Mated with Subtractive Machines
DMG MORI (Hoffman Estates, IL) has introduced the second in its line of hybrid additive/subtractive machines that integrates 3D printing technology onto its CNC machine platforms. A prototype of the Lasertec 4300 3D, which is based on the turn-mill NT4300SZ platform, will be debuted at IMTS. Production of the Lasertec 4300 3D begins later this year, with shipment expected in 2015. This marks the second of the company’s CNC machine platforms with 3D printing technology with more to follow.
The Lasertec 65, which debuted in late 2013 and begins shipping later this year, was the first hybrid additive/subtractive DMG MORI machine. The machine platform chosen was the DMU 65 monoBLOCK five-axis machining center.
The hybrid machines use a metal deposition process in which a powder nozzle sprays metallic powder into the laser beam, melting the powder in layers into the base material. DMG MORI said the process is up to 20 times faster than laser sintering in a powder bed. Most common metal powders can be processed, including steel, nickel and cobalt alloys, and brass.
The spray process builds up successive layers of different materials with wall thicknesses of 0.5–5 mm possible, depending on the laser and the nozzle geometry. Complex 3D contours can also be generated in layers without supports. The individual layers can then be accurately machined before the areas become inaccessible to a cutter or other tools due to deposited material interference.
Universal Five-Axis Machining Centers Built on Automotive Platform
GROB Systems Inc. (Bluffton, OH) has expanded its five-axis universal machining center line with the introduction of the G750 with a work envelope of 1280 diameter × 1005 mm (H) with axis travels of 1000 × 1100 × 1170 mm, table load capacity of 1500 kg while utilizing some of the highest rapid positioning rates in its size class. “The new G750, which was introduced at EMO 2013, can handle large workpieces for applications like moldmaking, aircraft parts, and general engineering,” said William Vejnovic, vice president. “Basically, GROB took their proven HMC platform, which had dominated the automotive industry, and created a new model to serve industries also demanding high precision and reliability, but in lower volumes,” said Vejnovic.
“GROB G series machines are different from other five-axis machines by their compactness that gives the end user a smaller footprint and large work cylinder, while supporting up to 500-mm long tools with no interference between the largest part and the longest tool throughput of the five-axis work envelope,” said Vejnovic. “Also a full fifth-axis capability of full work cylinder × 835 mm (H), allows the part and table to be fully inverted for machining upside down so chips just fall away from the part.”
The G750 was shown as a milling and turning machine at EMO in versions with and without pallet changer. In the milling/turning version with the HSK-T100 interface, the motor spindle delivers 306 N•m and can be used for turning. For a maximum workpiece diameter of 1280 mm, the turntable will allow a maximum speed of 500 rpm and generates a drive torque of maximum 4050 N•m.
The first machines in GROB’s line of stand-alone universal machining centers were the G350 and G550, both of which were shown at EMO with design improvements to NC axis acceleration, the addition of a nonwearing torque motor to the A axis, and the incorporation of dual Y-axis ballscrews and drives located as close to the spindle gage line as possible for improved static and dynamic rigidity.
Energy Poses Difficult-to-Machine Metals Challenge
“We approach many different markets trying to come up with better processes,” said Tim Leoni of Toyoda Machinery (Arlington Heights, IL). “We’re going after the energy sector, oil and gas, with emphasis particularly on the fracking market and have done quite a bit with product testing, and working different kinds of materials,” said Leoni.
“In the energy sector, we’ve been working with different cutting tool manufacturers, looking for heavy metal removal whether you start with a big block of 4140 steel, or stainless for the fracking applications. Components like pumps wear out fast so the market is trying different materials to make pumps last longer before they need to be replaced,” said Leoni.
“For another customer we’re trying to partner with another machine tool builder to combine our two types of machines into a single process using our 1250-mm 450 SW HMC for roughing and the other builder’s facing machine for contour finishing,” said Leoni. “Again in the energy field, there are a lot of five-axis machining opportunities for drill bits, which we have always done on our horizontal machining centers. We’re integrating floor-mounted robot loading into the process.”
Complete Lines of Machines for Tougher Metals
SMTCL-Americas (City of Industry, CA) is a subsidiary of the Shenyang Machine Tool Group (SYMG) companies. SYMG, which builds 80,000 machine tools annually, has established a three-pronged product development system with R&D and design engineering in Germany, and manufacturing in Germany and China. SMTCL manufactures a complete line of CNC milling, boring, turning, and drilling machines for the aerospace, defense, medical, energy, construction, and consumer products industries, among others.
To meet its customers’ requirements, SMTCL-Americas has been creating automated cells and continues to develop the cutting data for machining difficult-to-machine materials like those being used extensively in the aerospace industry. “For aerospace parts machining, the challenge is to be able to machine more titanium, more Waspaloy, more very hard metals,” said Jerry McCarty, COO. “The quantities aren’t necessarily the largest, but machine technology must be flexible to handle parts in different sizes and materials. Other product focus for our machine technology includes aerospace fasteners, medical components, and consumer electronic products. In R&D, we continue to work on macines and controls that are more reliable, more economical, and more productive.”
“We have been working with FANUC to create cells in which turning centers fed by bar feeders are unloaded by a robot and parts are then put into a tapping center,” said McCarty. The SMTCL model line-up includes a VMC, VTC, and Viva Turn 4 horizontal turning center. Designed in Germany and built in China, the Viva Turn 4 features a turning diameter of 260 mm, machining length of 800 mm and spindle with bar capacity diameter of 66 mm.
To address the need for trained replacement manufacturing talent, SMTCL-Americas has entered into an agreement with California State Polytechnic University (Pomona, CA) to supply equipment to establish a Machine Lab for its engineering students. SMTCL-Americas will train a Cal Poly intern in CNC machining and engineering each year.
New KIWA Horizontal Machining Centers Offer Many Benefits
Bernie Otto, KIWA product manager at Methods Machine Tools Inc. (Sudbury, MA) sees an industry trend for cost-effective horizontal machining center (HMC) solutions. “Although traditionally more expensive up-front, horizontal machining centers are viewed by many manufacturers as an alternative to vertical machining centers, for several reasons. Benefits from HMCs include accessible three-side machining, the capability of having multiple parts on a fixture, and multipallet pools that provide many advantages, including reduced setup times, longer run times, greater spindle uptimes and the potential of lights-out manufacturing,” said Otto.
At its Metal Storm 2014 open house event in June, Methods Machine Tools introduced a newly expanded line of KIWA HMCs. The new KIWA KMH series has pallet sizes ranging from 300 to 1250 mm, a 30 and 40-taper 300-mm pallet machine, and a 40-taper 500-mm model. The new machines include the KMH-300 series, offering dual 300-mm pallets, a 15-hp (11-kW), 15,000 rpm direct drive 30-taper spindle, an integrated full rotary B axis, and a FANUC Oi-MD control. “The KMH-300 series offers excellent chip evacuation and easy access for setup/maintenance,” said Otto. “With the introduction of the KMH Series, we now offer our customers an affordable, entry solution for horizontal machining with the dependability and consistency they expect from a KIWA machine and Methods Machine Tools.” ME
This article was first published in the July 2014 edition of Manufacturing Engineering magazine. Click here for PDF.
Published Date : 7/1/2014