A PRODUCTION COMPANY'S COMPETITIVE EDGE QUICKLY BECOMES ITS NEXT HOT TICKET ITEM.
Nagel multiple-spindle machining centers reduce changeover times and keep production runs on the go.
This side view shows a part in mid-cycle. The Nagel machine handles various materials in shapes and sizes up to 6.3 in.
A pick-and-place gripper arm grabs material blanks off loading cassettes for an efficient operation.
Most companies like to k e e p their internal activities secret, especially when they are using a product or process that puts them ahead of the competition. Not true for Nagel Maschinenbau GmbH, a German production company. This company designed and produced its own multiple spindle CNC machine to acquire a competitive production advantage. But the company's throughput gains soon aroused the curiosity of its own customers, and after some of them saw the machine in action, they wanted one — or more — for themselves. Although Peter Nagel, president and machine design engineer at Nagel, originally intended to improve only the efficiencies of his own manufacturing firm, he inadvertently designed a production solution suitable for many customers with various applications. So Nagel, realizing the opportunity at hand, quickly turned his proprietary machine into a readily available product for sale.
A great deal of the allure of this machine is that, despite a footprint of only 14 88 ft, it replaces two lathes and two milling centers. Essentially, Nagel machines combine the technologies of a turning machine and a horizontal/vertical machining center. They perform unattended, 6-sided machining, maintain tight tolerances, and achieve a standard repeatability of 0.0002 in.
All machine slide-ways are aligned to within 2 microns. Both the X and Z axes move in positive and negative directions, while the Y axis moves on vertical slides. In addition to these capabilities, the C-axis chuck provides even more flexibility. Because the chuck moves along the axes, Nagel's single and double production machines can perform work on angles anywhere from -3° to 93° at 360° rotation of the workpiece. Plus, off-center clamping and offcenter machining capabilities reduce work handling and operator involvement, making the machines even more appealing.
The compartments that house all moving components are pressurized with filtered air, which keeps components contaminate-free. Consequently, the machines work well in harsh environments.
As far as programming and controls are concerned, machine operators have several options. They can switch between Windows 98 and CNC mode. Operators can also write programs during production runs using a variety of applications. They can then send the programs back to the machine via a network direct-cable connection, phone lines, or email. The monitor can display part prints, preset drawings, production and maintenance records, and more — all while the machine is running.
The two-spindle machine follows a smooth operation process. First the pick-and-place grippers grab a material blank from a loading cassette and place it in the main spindle collet or chuck, which then moves to one of the two 12 or 16-position turrets. After machining is complete on the first side of the workpiece, the chucks interface and transfer the part. The second turret then begins work on the other side of the part, while the first chuck returns to loading position. Consequently, the machine possesses a full 10-axis capability — simultaneous 5-axis machining on two parts (or four parts with the double production machine).
Part changeovers are simple. Operators just exchange chuck jaws, pick and place grippers, and loader cassettes. The machine easily handles material blanks of any shape or size up to 6.3 in.
Sauter turrets, from ITI Tooling, Ramsey, N.J., offer bi-directional indexing, 30-sec toolchanges, repeatability to 0.0002 in., and live-tooling spindles. These live-tooling spindles are capable of 18,000 rpm, although Nagel limits them to 15,000 rpm for additional bearing life. According to the company, the machine's live-tooling capabilities increase production volumes and reduce processing time.
The main spindles are longer than most comparable machines and easily handle working forces up to 3,000 kg. According to the manufacturer, this rigidity adds to the long life and accuracy of the machines.
Before machine delivery, Nagel performs production efficiency tests. It examines each machining step independently and then tests the machine as a complete entity. Additionally, Nagel incorporates a modem into each machine so that it can track process compliance and troubleshoot from remote locations. If the machine's production efficiency ever drops below 90%, Nagel will intervene and correct the problem, returning the process to the more common 93 to 99% efficiency range.
New territory
The machines have been quite successful in Europe, and are now making their way into the American market. Nagel USA, based in Ft. Lauderdale, Fla., offers U.S. customers the complete line of Nagel multiple-spindle machines as well as service, support, and spare parts.
Quality Plus Precision Products in Rochester, N.Y., was Nagel USA's first customer. The company installed a two-spindle machine in late January and has been running it 24 hr a day — practically operator-free — ever since.
Quality Plus produces high-volume components — as many as 5 1 /2 to 6 million a month — for air conditioning and hydraulic systems. The Nagel machine pumps out many of these components easily, consistently, and accurately, reports John Nolan, president of Quality Plus. "On average, we only have to devote 2 man-hours a day to the Nagel machine, and that includes material stocking, routine maintenance, adding or checking cutting fluid, and tool verification or changes. We have uptimes in the range of 93%."
Quality Plus granted Nagel open Internet access to the machine for the first six months of operation. Consequently, Nagel has smoothed out the inevitable initial bumps in the road and has been providing the company with analyses and reports to help it optimize production runs, tool changes, cutting fluid management, and more.
"The versatility of the machine is one of its best features," adds Nolan. "We do 6-sided machining, as well as run a variety of blanks, including saw-cut, impacted, cast, and cold-headed blanks. Basically, it lets us do whatever we want within the size constraints."
Quality Plus operators also like the machine's control. They can write programs in many word processing applications, avoiding the complicated processes involved with many other control systems. The Nagel control also has monitors that tell operators when to change tools, perform scheduled maintenance, and so forth.
Says Nolan, "This machine works well on parts that don't re-ally have an appropriate fit on any other machine. For example, we would have to run five milling centers just to keep up with the equivalent output of the Nagel machine, and the manual labor involved would be onerous. But the Nagel machine fills a void in the high-volume machining industry that eliminates the need for several machines and operators. We intend to build a full department of Nagel machines in order to exploit this technology."
Ron Cappellini, manufacturing engineer at Baldwin Hardware, Reading, Pa., is equally pleased with the recent addition of a twin-spindle Nagel machine at his plant. "We're currently machining two parts simultaneously every 15 sec, which means a cycle time of 7.5 sec per part. Previously, we were machining these parts on conventional screw machines at a cycle time of 9 sec per piece. In addition to better cycle times, the Nagel machine also offers faster changeover times. Screw machine changeovers took up to 8 hr, while the Nagel machine, which only requires software changes, lets us switch from part to part in just minutes."
The Nagel machine has also eliminated the need for big wash tanks and wash systems because it dry machines. "The parts go straight from machining to polishing," says Cappellini.
Besides reducing changeover times and eliminating wash systems, Cappellini reports that the service has been exceptional. "We have had some minor glitches, and Marc Poehner, director of operations at Nagel USA, has personally responded to every one of our needs within 24 hours."
Pat White, president of Nagel USA, concludes that the caliber of her staff is of upmost importance. "Our foundation rests upon the quality of our associates, who, with their experience and skills, offer excellent service and support."
