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Productivity spurs
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Multiple edges and functions are key thrusts. By James A Lorincz
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 Heligrip systems have the ability to perform a variety of turning operations. |
At Iscar's headquarters, research into ways to improve its own patents and designs for carbide and ceramic tooling and inserts is supported annually by 10% of its resources. The company holds about 3000 patents which range from innovations in the development and finishing of metal alloys and sinters to the design of inserts and toolholders. Not surprisingly, the company acknowledges that a significant part of research and product development takes place in the factories of the world where manufacturers define--with their problems and needs--future trends in product development.
To Iscar, metalcutting productivity begins with a metal chip, the residue of the work of precision tools and inserts cutting into a piece of solid metal. Each type fits into a specific profile for the two main parts of a cutting tool: the insert, or small cutting element that is made from carbide or ceramic, and the toolholder.
The continuing challenge is how best to increase the productivity in metal-removal applications including turning, threading, grooving, parting, drilling, and milling through the right combination of material and geometry for metalcutting tools. Iscar's cutting tools, for example, are widely used in the automotive, aviation and aerospace industries, electronics and communications, defense industries, and by medical and dental device manufacturers.
Following is an edited version of a presentation by Prof-Dr-ing R Wertheim on The Development of New Insert Geometries in Metal Cutting and a commentary on Iscar products designed to meet today's manufacturing and productivity requirements.
"The development of insert geometries for the various metalcutting processes is aimed to improve the performance, chip control, and economy, as well as to optimize the use of modern machine tools. In the past, the producer and user distinguished very clearly between insert geometry for turning, threading, grooving, parting, drilling, and milling operations. The shape of most of the inserts was defined by standard ISO, ANSI, or DIN specifications, especially in the range of turning, threading, and milling. The ISO standard defined insert shape and size, clearance angle, corner radius, clamping systems, and gave some suggestions on the chipbreaker shapes.
"For operations like grooving, parting, and drilling, no real standards for indexable inserts and tools were commonly used. For these purposes every producer had his own shape, size, and clamping system.
"During the last few years different tendencies in the range of tool geometries have been observed. In addition to the ISO range of inserts more and more unique inserts shapes and clamping ideas have been developed. Instead of the standard pinlock clamp, top-clamp, wedge-clamp, or the central, simple screw for clamping, new ideas like self-clamping, prismatic clamping, resilient jaw clamping, and others have been developed.
"Due to the development of near-net shape production processes, an increased requirement for smaller inserts with a more universal shape for small depths of cut and low feeds can be observed. The clamping of these small inserts no longer can be done with the relatively large pinlock, central screws, or clamp option. The requirement to penetrate into narrow slots and to perform in multidirections accelerated the development of multifunction resilient tools which can machine in various directions.
"The use of automatic, CNC, and robotic controlled machine tools requires chip control in all machining conditions for various workpiece materials. Therefore, the optimization design of chipformers for processes like turning, threading, grooving, and parting, face grooving, and internal turning as well as optional chip control in milling and drilling are some of the main targets in R&D and production.
"For turning applications, standard ISO toolholders and inserts today still cover most of industry's requirements. The share of exchangeable heads, nonstandard tools, and inserts is gaining step-wise volume due to the above-mentioned tendencies in metalcutting. One of the main and probably most important developments was the introduction of the multifunction tool which can machine in various directions without the necessity to use different toolholders for radial machining and axial right and left machining."
New Line products
Taking precision tooling and inserts to the next level in metal removal is widely seen as the key to meeting demand by users for continuing productivity improvements, explains Bradley Teets, East division manager for its US-based arm, Iscar Metals Inc, Arlington Hts, TX. This evolutionary process in cutting tool development has challenged Iscar to continually develop new lines of tools since the introduction of its Self-Grip system in 1976, resulting in the subsequent development of the Iscar New Line inserts, such as Cut-Grip, Heligrip, and Do-Grip products.
 QNMG inserts have eight cutting corners for shoulder turning. |
When Iscar launched three new lines of products last year--one line each for multifunction turning, for standard ISO turning, and for milling applications--the products were marked by their ability to provide more functions by each edge or by the higher number of cutting edges or cutting edge corners available.
"Our three product innovations are designed to improve machining performance, to simplify use, and to reduce stocking requirements--three key bottom line considerations for productivity-conscious metalworking manufacturers," explains Mr Teets.
The three lines include:
*The Heligrip system with the ability to perform a variety of turning operations with a single insert;
*The QNMG inserts with eight cutting corners for shoulder turning; and
*Heliocto tools which increase the number of effective cutting edges to eight in milling operations.
Multifunction turning. The Heligrip insert system takes multifunctionality to new depths of cutting, says Mr Teets. The concept is based on a single, double-ended, twisted insert that can be used for at least eight different operations. Most important, the unique twisted design of the double-ended Grip insert body makes it possible to machine to depths much larger than the length of the insert itself. As the insert penetrates the workpiece due to its slanted rear angle in relation to the frontal edge, it avoids "back side" contact with the side-machined surfaces. Available in 4, 5, and 6 mm widths, the Grip inserts simplify and improve machining to 1.5创 depths for face machining and external machining, and for larger depths in grooving, parting, and recessing mounted on standard DGFH blades. The same insert, when mounted on external, internal, and face machining toolholders, can carry out any combined operation without the need for several different standard or special turning inserts. Generally, insert design provides chip control, surface quality, high removal rate, the ability to machine in any direction, and improved tool life under a wide range of machining conditions, says Mr Teets.
 Heliocto milling cutters increase the number of effective cutting edges to eight. |
90 deg shoulder machining. The new QNMG square insert widens the ISO standard range. This negative/positive insert has eight cutting edges to machine 90 deg shoulders in longitudinal and face turning directions. The slightly curved cutting edge design makes possible side turning next to shoulder to a depth nearly equal to the complete cutting edge length. The insert's mounting position eliminates contact between the rear corner and the workpiece. When mounted on face turning holders, similar machining advantages apply in the face-turning direction. Facing diameter is unlimited due to the very small clearance between the rear-cutting edge and the workpiece.
The new QNMG insert (eight cutting edges) represents another step in the evolution of the popular Trigon 80 deg axial and face-turning corner of the WNMG insert (six cutting edges) and the CNMG insert (four cutting edges), which cover most industrial needs. For shops that haven't made the transition from the widely used CNMG insert to Trigon inserts, the QNMG insert with eight cutting edges will cut by half about a third of the dollars spent for their turning requirement, Mr Teets points out.
Parts such as longer tube-type workpieces, stepped shafts, discs, and bushings can be machined with much higher efficiency and economy than with standard 80 deg and Trigon-shaped inserts. For automotive, tube, bearing, and hydraulics producers, the production advantage is obvious, says Mr Teets. Also new is the QCMT, a positive, square insert with four cutting corners to replace traditional CCMT insert with only two cutting corners. The design includes a small 7 deg relief flank necessary to guarantee the clearance in the horizontal positioning of the insert, below a negative flank surface for improved positioning and to guarantee repeatability with increased stability.
Multiple milling edges. The new Heliocto OEMT insert with eight cutting edges is designed for more economical facing, shouldering, slotting, recessing, and chamfering. The new insert meets the demand to machine smaller workpiece oversizes with less stock removal. The high positive rake and grooved rake face design result in a cutting tool that is well-suited for low-powered milling machines.
The combination of Iscar's unique helical cutting edge configuration enabling a large heli-angle with a new rake design offers a self-balanced, stable solution for cost reduction and high performance in many systems. The special wiper flat design on each of the eight cutting edges offers good surface finish on ductile materials as well. The rake face of the new insert is equipped with a sequence of depressions to reduce the contact area between the chip and insert for lower heat conductivity into the insert, less friction, and longer tool life. The positive rake angle in combination with these depressions reduces cutting forces and machining power, improves chip flow, and extends tool life.
The new inserts OEMT 060405 AER-76 are mounted on F45KT milling cutters with Weldon shanks or for arbor mounting in the range of 11/4创 to 5创 (32 to 125 mm) dia. The pocket design ensures true positioning of insert and high repeatability. For smaller depths of cut up to 3/32创 (2.4mm), eight cutting edges can be used; for depths of cut up to 5/32创 (3.7mm), seven cutting edges can be used; and up to 9/32创 (7.4mm), the actual number of usable cutting edges is four. Heliocto inserts are available in PVD-coated IC 328 for general use on carbon steel and steel alloys and in very tough, uncoated IC28 for high temperature alloys.
For more information from Iscar Metals Inc, Arlington Hts, TX, circle 230; http://www.iscar.com
Vision in the hills of Galilee
Less than five miles from the hills of southern Lebanon on a hilltop in Tefen in the Western Galilee of Israel, cutting tools and inserts are designed and produced for the world metalworking market by Iscar Ltd, the flagship for a group of endeavors that go far beyond metalworking. There are education, culture, regional development, and entrepreneurship nurtured. The guiding vision is that of Stef Wertheimer, founder and chairman of the Iscar Group.
"The word employment should be replaced by the word creativity," he says. At Iscar, industry is "a beautiful word" and the source of what Stef Wertheimer envisions as "the peace benefit." The Wertheimer family (his Harvard-educated son, Eitan, is president of the Iscar Group) has built a model of success in industry, education, cultural activities and regional development that they believe can serve as a model for financial security for Israel and her neighbors. The secret lies in exporting--95% of Iscar's metalcutting tooling production is exported to countries around the world. The entrepreneurial industrial parts that Stef Wertheimer has sponsored and personally built at Tefen and at two other Israeli locations are incubators for fledgling businesses in consumer and industrial markets-- again for export. The vision that Stef Wertheimer communicates to anyone who will listen is at heart an entrepreneurial approach to solving the region's problems:
"Progressively managed industry brings people together, focuses on common objectives, links education directly to work and provides stable financial and social security.
"If the region moves beyond the outmoded, bitter conflicts over land and water and chooses to make money instead of war, bridges will be built--of hope and friendship--leading to an improved quality of life for the entire region."
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