Mitsui Seiki (USA)’s Vertex Hybrid G series of five-axis VMCs (models 55-5X, 75-5X and 100-5X) offer high speed, lights-out milling and grinding of die and mold, optical, and tooling components. The machines are capable of 0.0003" (7.5 µm) precision in 3+2 or simultaneous five-axis machining, and their main spindles rotate as fasts as 25,000 rpm. Air spindles enabling speeds ranging from 40,000 to 90,000 rpm can be changed via ATC.?
Fanuc 3D volumetric compensation features enable volumetric calibration according to ISO10320-2 standards and the use of in-process 3D (NIST) traceable measuring DCMT Insert capabilities. A part spinning process produces tangential planetary work spindle alignment, emulating the U-axis motion of jig grinding equipment. The machines can employ trochoidal dynamic power or high speed cutting strategies for tools rotating as fast as 90,000 rpm.
Key features include automatic, in-process grinding wheel dressing and size measurement and wheel calibration. Acoustic emission sensors and software-guided application strategies monitor milling and grinding process finishes.
The VMCs feature cast iron beds and a solid “box-in-box” design that contribute to rigidity, stiffness and agility. Positioning accuracy is 0.001 mm (0.000040”) in the X, Y, and Z axes, ±6 arc seconds in the A axis, and ±4 arc seconds in the C axis.
Hand-scraped guideways contribute Carbide Milling Insert to precision. A thermal compensation system facilitates size consistency, and glass scales provide a minimum resolution of 0.001 mm.
Mag offers an integrated contouring head for horizontal boring mills in 1,250 and 1,600 mm (49.1" and 63") table/pallet sizes and live-spindle horizontal machining centers in 800 to 1,600 mm (31.5" to 63") pallet size. The contouring head can produce bottle bores, valve seats, seal faces, phonographic sealing surfaces, O-ring grooves, straight/tapered threads, chamfers, external profiles and other features. It is designed for single-setup rough and finish machining for oil and Coated Inserts gas parts, or other large parts that combine bored, milled and turned features. The head is available with a Kennametal KM80 or Sandvik Coromant Capto C8 tool interface.
The contouring head has a standard tool interface and loads tools via the machine’s automatic toolchanger. An absolute positioning slide handles diameters ranging from 50 to 540 mm (2" to 21") with tools as long as 600 mm (24"). The contouring spindle’s U-axis slide stroke provides the ability to produce small- or large-diameter features without head changing or manual intervention for machining complex features in a single set up. The live boring spindle can use 50 taper tools as long as 750 mm (29.5"). An auto-coupler enables the use of feed-out tools such as programmable boring bars.
The head is designed as a drop-in Carbide Milling Inserts module that can be added during manufacture or later and removed for service without affecting the operation of the boring spindle, the company says. The contouring spindle for both boring mills and HMCs is located immediately above the machine’s main spindle but slightly offset in the Y and W/Z axes to avoid tool interference. Rated power is 56 kW/75 hp on boring mills, and 45 kW/60 hp on HMCs.
The microdrills in the CrazyDrill Flex line from Mikron Tool (Monroe, Connecticut) are designed to combine the advantages of HSS (flexibility and resistance to breakage) with those of solid carbide (precision and resistance to wear). This combination makes the drills reliable in difficult drilling situations yet very productive in holemaking capability. The Flex line covers diameters ranging from 0.1 to 1.2 mm in 0.01-mm increments. Two length categories are available for holes as deep as 20 times diameter or 30 times diameter.
According to the company, the Carbide Grooving Inserts drill’s unusual flexibility is attributable to two factors. For one, the drills are made of a new carbide alloy that is engineered to have mechanical properties that make it less brittle than other carbides and more like HSS in terms of what the company calls elasticity. For another, the geometry of the drill includes an extended neck with a reduced cross section between the shank and the fluted cutter head. As a result of these engineering concepts, the Flex drill is slightly bendable. It can flex from 0.1 to 0.6 mm from center, depending on the overall length of the neck.
Furthermore, the carbide alloy retains the wear resistance and hardness of typical carbides, the company says. This enables the drills to remove material faster than HSS and last longer before dulling. In addition, a 140-degree point angle and wide flutes Carbide Threading Inserts aid chip breakage and evacuation. Smooth chip flow also reduces cutting forces such as torque and feed force. This geometry is also said to prevent stringy chips from wrapping around the neck or shank.
Having HSS-like flexibility and carbide-like wear resistance makes the Flex drills suitable for situations in which holemaking equipment offers less-than-precise drill positioning. Positioning error can be caused by misalignment in the rotary indexing tables of transfer machines, the spindle drums of a multispindle lathe or drill stations in a series. Thermal expansion on a machining center can also cause misalignment. In any of these cases, the drill’s slight flex can compensate for misalignment, thus preventing excessive side forces from snapping the tool. The resulting reliability of the microdrill and its capacity for high drilling speed makes it useful for lights-out or lightly attended operations, the company says.
According to the company, the performance of these drills makes holemaking operations on these machines competitive with small-hole EDM (electrical discharge machining) and laser drilling. The company reported a test cut involving 10 holes measuring 0.5 mm in diameter and 15 mm deep. The Flex drill took 3 minutes to perform the operation versus 24.4 minutes for gundrilling and 30 minutes for EDM.
However, using this type of microdrill may require a change in CNC holemaking routines. Drills in diameter sizes at the low end must have a pilot hole produced by a CrazyDrill Flex Pilot drill of the same diameter. The pilot hole, which works best at three times the drill diameter, centers the Flex drill and stabilizes as it as it enters. Also, while holes as deep as seven times diameter can be produced in one step, drilling deeper holes (as deep as 30 times diameter) requires additional pecking cycles.
These microdrills have been used successfully to drill deep holes in aluminum, brass, copper and steel. The company reports the main applications to be micromachining of precision parts in the watch and medical industries or for machining fuel injection components.
In order to effectively machine metal, cutting tools are made of hardmaterials like PCD (polycrystalline diamond). However, hard materials are hard to machine; it can be challenging to transform these materials into cutting tools that have sharp, stable cutting edges and complex features like flutes and gashes, especially through mechanical processes like grinding. PCD can be more easily eroded via processes like electrical discharge grinding (EDG) because the diamond is held in an electrically conductive binder material such as cobalt. “The process works by using a copper electrode on the super abrasive material and binders,” explains Tom Nathan, EDG product manager at ANCA. “It uses micro sparks to erode away the binder, rather than using a wheel to mechanically grind away the material.” Use of a wheel-shaped CNC Carbide Tool Insert electrode instead of a static electrode, such as in wire or sinker EDM, gives users the ability to create the same complex geometries that five-axis grinding machines can, enabling the production of 3D features such as flutes, gashes and reliefs on all types of drills, end mills, reamers and profile tools.
But the speed of the EDG process and quality of cutting tools it can produce have been limited by factors including spark generation and erosion parameters. By expanding the power range and introducing new intelligent erosion control features, ANCA’s EDG machines are designed to help users produce better cutting tools, faster, potentially advancing the efficiency with which cutting tool makers can now produce PCD tools.
For the erosion generator in its EDG machines, ANCA turned to sister company ANCA Coated Inserts Motion to develop the SparX Erosion generator, which is designed to give users access to a wider range of power than other systems. This wider power range enables ultra-fine finishing operations that can produce parts with good surface quality. “What we've found recently with our erosion processes is that we can easily get our surface roughness to under 0.1 micron RA,” Nathan says. Good surface finish means sharper cutting edges, which enables tools to perform better and last longer. On the other end of the power spectrum, the new erosion generator can handle heavy roughing operations that increase material removal rates and decrease cycle times in cutting tool manufacturing by as much as 50%, the company says.
The EDG process is optimized for PCD, but PCD cutting tools include other materials as well. The PCD is placed along the cutting edges of the tool, while the rest of it is made up of another material, such as carbide. “If the PCD is in areas that it's not cutting, it's not doing any work, and it's more expensive than regular carbide or high speed steel to manufacture and form,” Nathan notes. In order to be able to machine multiple materials, ANCA’s EDG machines combine both traditional grinding and EDG capabilities in a single platform. “We grind all of the operations that don't require erosion, so that would be, say the fluting in a helical tool, and then we use the erosion process to do all the cutting edges,” he explains.
But eroding the area where the PCD and carbide binder meet can pose a challenge. Nathan explains that there’s usually a 0.6 mm layer of PCD with a 1 mm layer of carbide underneath. “The bit where they meet is called the undercut, and the reason it's called the undercut is, traditionally, when you erode from PCD to carbide, the system wants to over-erode the carbide because it's much more conductive, so you get a lot of undercut at the carbide-PCD border.” He says the result is similar to digging underneath a footpath. It’s easier to dig below the footpath than it is to dig through the footpath, but if you dig underneath it deep enough, the footpath will collapse in because there’s nothing below to support it.
In order to solve this problem, ANCA has developed a feature called Adaptive Spark Control (ASC). “It can sense what substrate it's eroding (PCD or carbide), and it can change the spark profile to be optimized for each material,” Nathan explains. It does this by gaging the voltage, current and resistance of the sparks it’s generating. The system uses this data to determine if it’s eroding carbide or PCD and adjusts itself accordingly. By optimizing the sparking for each material, the undercut is reduced, which increases the strength of the tool so it’s less prone to chipping, which in turn increases tool life. As an example, Nathan described one of ANCA’s customers, which was producing drills for carbon fiber-reinforced plastics. Using its previous tool grinding system, the company was getting 3 or 4 holes per drill point. After implementing Adaptive Spark Control, the number of holes per drill increase to 44. “It was a huge increase in productivity and effectiveness of those tools from that one feature,” he says.
Figuring out feed rates can also be a challenge for users of EDG. “If you have a ‘dumb’ process, which is just using the erosion parameters, it's moving forward at a set feed rate,” Nathan says. “In many instances, it will be traveling too slowly, and you're just wasting time. In other instances, you will be traveling too quickly, and you will risk actually hitting into the PCD material, which is also not good.” And when the electrode moves in five axes, as it does in EDG, determining feed rates becomes even more complicated.
In order to help optimize feed rates and speed up the EDG process, ANCA developed a featured called Intelligent Adaptive Control (IAC). “It reduces the airtime when you're not actually eroding anything because the erosion gap’s too wide,” Nathan explains. According to the company, this can reduce air time by as much as 30%. It also helps prevent contact between the wheel and part, which can damage both. “It's really essentially important for creating micro tools, because if the wheel contacts the tool, it will snap the tool,” he adds.
Micro-tools (tools than are less than 0.5 mm) are a major application for ANCA’s EDG systems, Nathan says. The company is currently seeing high demand for these capabilities in Asian markets. “They use a lot of ceramics in their Printed Circuit Boards (PCBs), and ceramics are very aggressive,” he says. “Because of that, markets are moving more towards PCD-type tools.” He adds that the company is also seeing inquiries from European and American markets for micro-tools for medical and aluminum applications as well.
Sumitomo’s SMD 12×D replaceable head drills allow for deep-hole making at a lower cost. SMD users buy just one drill body to fit up to five head sizes.
Featuring an original radial serration coupling design, SMD drill heads or tips are designed for high-precision, stable drilling. A polished flute ensures good chip evacuation.
The SMD’s nickel-plated body provides longer tool life than conventional replaceable tip drill bodies. A tough carbide substrate with patented DEX coating offers excellent wear-resistance at the cutting edge. A rigid serration coupling system affixes the replaceable carbide tips to the drill face, improving drill accuracy and repeatability.
Cemented Carbide Inserts Sumitomo offers a range of drill tip styles to improve performance in a variety of materials. The SMDT-MTL drill tip excels in steel applications, while the SMDT-C has a chamfered edge to eliminate breakout in cast iron applications. The SMDT-MEL machines super alloys, stainless steels and cast iron proficiently.
Along with the new 12×D, Sumitomo’s SMD line APKT Insertincludes 3×D, 5×D and 8×D replaceable carbide tip drills.
