From physics class Cutting Tool Inserts we learned that the linear velocity at the center of a spinning disc is zero, while maximum speed occurs at points around the disc’s perimeter. What that means for a drilling operation is the drill’s point remains stationary while its outer cutting edges rotate at high speed. The resulting pressure on the point can cause it to chip if the drill’s substrate doesn’t have sufficient toughness. However, the substrate must also provide adequate hardness to prevent premature wearing of the fast-moving cutting edges. Therefore, drills made from a single carbide grade must find a happy medium between toughness and hardness.
ATI Stellram (LaVergne, Tennessee) has developed a dual-carbide-grade drill technology called HardCore that is said to possess both of these attributes. These drills have a core made of a micro-grain carbide grade blended to provide toughness and shock resistance WNMG Insert at low rotational speeds. This hinders chipping at the drill’s point. Surrounding the core is a second carbide grade that provides sufficient hardness for wear resistance at the outer edges. According to the company, this dual-carbide technology can provide four times the life of other drill designs and cut drilling operation times in half.
The drills feature a 140-degree point geometry, TiAlN coating and open flute profile to assist in chip evacuation. They are available in diameters ranging from 3 to 16 mm (0.118 to 0.63 inch) and maximum length-to-diameter (L:D) ratio of 5:1 for cutting steel and cast iron. Coolant-through versions with L:D ratios as high as 8:1 will soon be available. The drills are suitable for use with minimum quantity lubrication (MQL), although, the company recommends using coolant-through models for stainless and heat-treated steels.
HardCore technology is currently available in drill versions for iron, steel and titanium with hardness as high as 50 HRc. The models for drilling titanium have a more positive geometry with smaller defined edge preparation. The company says it is developing drills using dual-carbide, replaceable tips in addition to other types of cutting tools.
Sandvik Coromant offers several turning and auxiliary digital machining products to help manufacturers improve cycle times, increase parts per run, decrease machine downtime, and eliminate duplicate work and scrapping of expensive materials.
Turning Reinvented includes CNC Inserts the Y-Axis Parting product and the PrimeTurning solution. Designed to improve stability, the CoroCut QD part?-off blade feeds in the Y direction to realign cutting forces and reduce noise levels. The top face of the insert is now placed parallel to the end of the blade, rotating the insert seat 90 degrees counterclockwise. The blade cuts into the workpiece with its front end, which roughly aligns the resultant vector of cutting forces with the longitudinal axis of the blade.
PrimeTurning includes two CoroTurn Prime tools and the PrimeTurning code generator, which supplies optimized programming codes Carbide Grooving Inserts and techniques. CoroTurn Prime inserts have three edges per corner for longitudinal, facing and profiling operations, respectively. This construction distributes wear over a longer edge and not just the insert tip. It also moves heat away from the cutting zone, increasing insert life.
Digital solutions include CoroPlus ToolGuide and CoroPlus ToolLibrary, which recommend and organize tools, respectively. CoroPlus Process Control includes CoroPlus Collision Detector, CoroPlus ToolGuard and CoroPlus Machine Health Inspector.
When Hardinge Inc. (Elmira, New York) designed its new “flagship” line of multitasking CNC turning centers, it paid particular attention to the turret tooling top plate. On this type of machine, the top plate plays such a critical role that it can be either a weak link or major strong point. Well aware of this, the company chose a turret style that features a self-aligning top-plate configuration. This turret top plate system is integrated on the RS-Series of multitasking turning centers with a “collet-ready” spindle and is available on the SR-Series multitasking turning centers for universal chuck and bar work.
What made the designers so conscious of the top plate’s importance was the experience of the firm that developed this turret design. That firm, Eppinger GmbH, is a German tooling manufacturer originally founded as a maker of static toolholders for lathes. During the last 20 years, the company shifted its focus to live tooling for CNC turning centers. Along the way, Eppinger acquired several Super-Precision Quest turning centers from Hardinge to do hard turning. The turning centers were equipped with VDI tooling top plates, which are commonly found on this type of machine. According to Uwe Eppinger, company president, this application was quite successful.
However, the company discovered that, as effective and flexible as VDI-style tooling is, something more was needed to take machining of hardened materials to the next level of precision and productivity. The VDI system, which is based on a standard that defines a tool shank and matching machined pocket, did not lend itself to extreme hard-milling and hard-turning applications with live tooling in a multitasking environment. Greater rigidity and more precise alignment were called for.
Drawing on its firsthand understanding of these machining challenges, the company developed a new concept for tool-turret design. Rather than relying on the machined tool pockets to position the toolholder body, the design uses a zero-clearance key system. Each of the turret’s 12 stations has a key used to move it along Y axis for a virtually perfect alignment with the centerline of the main spindle. In turn, each toolholder body is positioned with a keyway that is pulled against the key on the top plate. The key makes contact with only one side of the keyway so that key and keyway clearance is not a factor in positioning accuracy. A pushbutton on the top plate activates the gripper retention knob for “hands-free” tool installation. The four bolts that attach the toolholder body to the backplate’s ground surface provide rigidity while tightly locking in the precise positioning, the company says
The toolholder bodies are designed to interface with the company’s modular tooling system. Called Preci-Flex (for precision flexibility), this system features interchangeable components. In each toolholder body, the spindle-collet seats have a ground spindle nose with four threads. The spindle of the toolholder body accepts either a traditional ER collet or an SNMG Insert adapter with a cone-face contact that is the same shape as a collet. The adapter is bolted down under the spindle and sits in the ER seat, so it has contact with the ground spindle nose. According to the company, this results in high repeatability and a very rigid connection between the adapter and the spindle.
With the adapter, the cutting tool can be clamped and preset outside the machine while the toolholder body remains attached to the top plate. Cutting tools and adapter assemblies can be exchanged quickly and still achieve highly repeatable positioning with low runout. Precise alignment of the toolholder bodies combined with the low runout of the adapters prolongs tool life because cutting conditions are highly consistent whether turning or milling hardened materials, the company says. In addition, each station can be equipped with a driven tool for cross or end milling/tungsten carbide insertsdrilling operations.
As a Hardinge customer, Eppinger was eager to share its new turret technology with the machine tool builder. Because of the system’s apparent advantages, Hardinge was equally interested in integrating this turret design on its new CNC turning centers. The Eppinger Self Alignment (ESA) turret is supplied on an exclusive basis as a standard feature for the RS-Series and as an option on the SR-Series.
The two companies concur that the ESA turret complements the capabilities of the new Hardinge multitasking turning centers for which it was designed. The RS-Series machines are intended for hard milling and hard turning complex workpieces in one setup. They feature a collet-ready ground spindle and linear guideways. The series comprises two ranges: three Super-Precision models with overall axis repeatability of 0.00003 inch/0.76 micron, and three general precision models with overall axis repeatability of 0.00005 inch/1.27 micron. Available in two sizes, the SR-Series machines are positioned as heavy-duty “chuck-and-bar” turning centers. The design includes roller guideways and oversized ballscrews. Featuring a 150- or 200-mm three-jaw chuck for applications requiring high horsepower (as much as 30 hp) and high torque (as much as 270 foot-pounds), the models mark the company’s entry into the market for chucking machines in this size range.
The Carbide Inserts Website: https://www.estoolcarbide.com/tungsten-carbide-inserts/vbmt-insert/
Shops that continually follow and integrate the latest metalworking technologies will produce parts with increasing speed and quality. The same is true for savvy shops that apply proven technologies in new, innovative ways. Harmonic Drive LLC offers an interesting example of the latter scenario. The manufacturer’s efforts to reduce setup times for machined components led it to adopt a modular, quick-change tooling system for all of its CNC lathes. In doing so, it discovered it could use the same modular interface as a universal workholding coupling, speeding workpiece change-overs for components that travel across multiple pieces of equipment.
This Peabody, Massachusetts, manufacturer produces harmonic drives used for precision motion control and mechanical power transmission applications in nuclear power and aerospace industries, among others. According to Steve Foley, shop supervisor, 50 percent of his machine operators’ time is dedicated to job change-overs. That fact, combined with lot sizes that typically range from two to 25 workpieces, means that reducing setup times in this short-run, JIT production environment is paramount.
Years back, the company adopted rod peeling inserts block-style tooling to allow faster tool changes on its lathes. It has since modified all its lathes to accept the Capto modular tooling interface from Sandvik (Fair Lawn, New Jersey). According to Mr. Foley, one of the reasons for the switch was that the Capto interface offered improved rigidity versus the block-style tooling, especially for ID turning operations.
However, there was still work to be done to speed part fixturing time. Some workpieces traveled across different types of machines, and the workpiece would have to be indicated to each machine. It dawned on Mr. Foley that the modular tooling interface he used for quick tool changes could also be applied to workholding. Now, equipment such as lathes, gear hobbers and inspection devices uses the Capto interface as a workholding device so that lengthy indicating Carbide Insert for Cast Iron time is eliminated.
The Capto modular tooling system has been available for a number of years, and it can be used for milling, drilling and turning (static and rotational) operations. The system consists of a cutting unit (part of the toolholder) that couples with a clamping unit installed in a lathe’s turret or machine’s spindle. Its tapered, three-sided polygon coupling centers and aligns the toolholder in the clamping unit, providing 0.0001- to 0.0002-inch runout, according to Mr. Foley.
To use the Capto coupling as a workholding interface for his lathes, Mr. Foley installs a receiving clamping unit on a faceplate mounted in the lathe’s spindle. Custom toolholders are made from boring bar blanks that have the Capto C6-sized coupling (this is the largest available coupling size). The boring bar blank is machined to accept the different types of parts the company machines. According to Mr. Foley, the Capto system reduced part change-over time from 5 minutes (using a straight shank tool that requires indicating) to 30 seconds.
The Capto interface is especially effective working in conjunction with a nifty “lollipop” workholding method used to secure small, bell-shaped workpieces for lathe work, spline machining and OD inspection. The part, called a flexspline, begins as a 15-5PH stainless steel forging. Its ID is machined to leave a wall thickness of approximately 0.06 inch. A final wall thickness of 0.01 inch is attained through OD turning.
The OD turning is easier said than done, though, because the flexspline’s shape and thin wall present unusual workholding challenges. The part by itself can not be clamped in a lathe’s chuck because the very thin walls would not provide adequate support during the turning operation. Mr. Foley mounts the part on an arbor machined from a Capto boring bar blank. However, because of the bell-like internal profile, voids exist between the arbor and workpiece inner surface. To fill these voids, a low-melt-temperature alloy is poured through a bore that is machined down the center of the toolholder. Once the alloy solidifies, then the part and arbor bond together to become one. The alloy provides the wall support required to machine the part to the desired 0.01-inch wall thickness.
Once the part’s OD has been turned, the part becomes concentric to the arbor and Capto coupling, and succeeding operations no longer require indicating. For the flexspline, the next operation is machining a spline around the perimeter of the part’s “bell mouth.” Similar to the lathes, the gear hobber uses a Capto clamping unit attached to a faceplate installed in the machine. Once the hobbing operation is completed, the part is delivered to an inspection device to perform rotating concentricity runout checks. Mr. Foley topped a precision grinding head with a Capto clamping unit, having confidence that the Capto interface would not adversely affect runout inspection. Once machining and inspection are completed, the flexspline is removed from the arbor by simply heating and melting away the low-melt-temperature alloy. It is then ready for assembly.
Remote Machining melds two seemingly antithetical concepts—control and freedom—so that shops can do some reconnaissance work or tweak parameters on their own terms. The manufacturer’s self-titled, all-hardware interface grants real-time access to all CNC functions via the Internet so that shop personnel can manipulate the process, regardless of their proximity to the actual machine.
Operators can edit programs, check cut progression or troubleshoot from any PC—be it in a hotel lobby or a home office—as long as there is Internet connectivity. The interface assuages logistical concerns for the user without taxing the machine’s brainpower. It consists of an adapter and a centralized controller, which are completely independent of software, operating system or controller type. The virtual “spy” does not encumber the CNC. Rather, it gains access by splicing into the I/O from the controller side. In essence, the machine is not even cognizant of this “spy.”
“The product is piggybacking, not taxing the control with extra functions,” explains Tim Zott, president of Remote Machining (West RCMX Insert Bloomfield, Michigan).
The product is compatible with machining centers, grinding machines, lasers, lathes, plasma cutters, waterjets, EDMs and other CNC-controlled machines. Thus far, it has been predominantly adopted in EDMs because they are generally run unattended more frequently than other machines. Makino offers the interface as a third-party option for its wire and ram EDMs.
Basic shopfloor requirements are at least one PC with Internet connectivity in the building and a LAN connection (within cabling distance) to the machine. Shop personnel can log on to their company’s own internal infrastructure to tinker with certain parameters and functions, but in such a way that does not interfere with the integrity of the process. All modifications must be in accordance with OSHA regulations, which stipulate that axes cannot TNGG Insert move without an interlock system. Thus, Mr. Zott says, users can’t execute changes that cause direct movement of the cutting axes outside of what is specified in the loaded program. They can, however, check in periodically to see if alarms have been triggered or to gauge overall machining efficiencies and possibly make adjustments.
“With EDMs, for instance, the shop could modify cutting parameters remotely,” explains Brian Pfluger, Makino senior applications engineer. “Although it can’t start the machine, the shop could edit the speeds and feeds and power elements, as well as halt production.”
From an application support standpoint, the product can better equip engineers to bridge the gap between perceptions of what is going on with the reality of what is actually occurring at the machine. Mr. Pfluger says the system is beneficial when providing technical assistance and when training new users, especially during the first year of machine ownership.
“This often helps us make machining adjustments so that the customer’s part is running more efficiently,” he comments.
This first year of ownership, Mr. Zott says, typically represents the highest incurrence of costs related to technical services and support as well as machine downtime. This product can ease some of those expenses.
“Now, a 15-minute conversation might suffice instead of the lengthy and often frequent exchanges between the application engineers and new machine users,” he says. “The manufacturer’s engineer need only log-in through a secure access port to view the CNC screen and adjust parameters—all of this can be done live with the machine operator logged on as well.”
The Carbide Inserts Website: https://www.estoolcarbide.com/product/vcmt-cemented-carbide-turning-inserts-use-for-steel-cutting-p-1206/
