That was yesterday. Today, the productivity needed to be globally competitive requires ever increasing metal-removal rates during operations such as roughing and high-speed slotting. Process reliability is paramount, especially when working with difficult-to-machine materials. Conventional toolholders typically do not cope well with the high axial forces generated by aggressive machining, and cutter pullout can occur.

Several years ago, Haimer developed and patented an anti-pullout system, Safe-Lock, as an optional feature on its shrink-fit holders and power collet chucks. Safe-Lock employs special drive keys in the holder and mating grooves in the tool shank, ensuring positive locking in place of the cutter and preventing spinning and pullout. Unlike Weldon flats, the mating ground grooves are perfectly symmetrical, thus eliminating issues associated with unbalance and uneven side loads. The system also provides users with the ability to adjust the axial position of the cutting tool in the holder. With 14 of the largest round tool companies as official licensed partners, tools from any number of global suppliers are readily available.

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As part of the stand at Mach, the company will also be demonstrating its PCD cutting tool portfolio. The range of PCD milling tools includes 2, 3 and 4 cutting edge PCD slot drills and end mills with through-coolant that are all available with a wide variety of shank forms and tolerances, surface finishes and coatings, helix and rake angles and cutting edges.

Rego-Fix Tool Corp. (Indianapolis) markets both a friction fit and a tool locking system. The powRgrip series includes holders, collets, and automatic or manual pressing systems. The collet is pressed into the holder with up to 9 tons (8.16 t) of pressure, which Rego-Fix claims to be the highest clamping force in the industry. The compression contacts the nose of the holder and not the taper.

From a dimension perspective, the new RF 100 5 and 7 Speed are available with cutting diameters of 6, 8, 10, 12, 16 and 20 mm with a necked diameter that permits cutting depths from 20 to over 60 mm depending upon the diameter selected.

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Toolholder manufacturers have responded with a variety of rigid, highly secure systems offering anti-pullout protection. These include shrink-fit, hydraulic expansion and locking toolholders. Each features high gripping torque (clamping force) for a tight friction fit on the tool shank. Many offer proprietary locking mechanisms that can guarantee up to 100% tool retention.

Haimer is best known for its extensive line of shrink-fit toolholding. This system is a simple one-piece, highly rigid design with no moving or wearable parts. Benefits include runout accuracy up to 0.00012″ (0.00305 mm), superior repeatability, minimum vibration and chatter and excellent balance, according to the company.

For many generations, machining was a largely manual process with relatively slow speeds and shallow cutting depths. The most common toolholders were Weldon/sidelock chucks and ER collets, and, under these comparatively benign machining conditions, cutting tool slippage or pullout was not a serious issue.

The 4-flute end mills are suitable for machining steel, stainless steel, aluminium, aluminium alloys and other challenging materials. (Source: Gühring)

Drew Strauchen, vice president, marketing and business development, Haimer USA LLC (Villa Park, IL), cautioned against total reliance on the ability of friction-fit holders to provide maximum tool security. “High gripping torque by itself does not equal guaranteed pullout protection,” he said. “The incredible cutting forces generated by faster machine spindles and more aggressive toolpath strategies [like full radial engagement trochoidal milling] have exposed the limitations of even the best friction-fit clamping systems.”

An exclusive Key Grip locking mechanism provides anti-pullout protection. It is placed into the Weldon flat of the end mill shank, which is then inserted into one of the three Key Grip grooves inside the chuck. A spring functions to remove the gap between the Key Grip and the wall of the groove. Tightening a clamping nut secures the Key Grip in place, achieving dual contact between the nut and chuck body for rigidity close to that of an integral cutter.

One of BIG Kaiser’s newest products, the Mega Perfect Grip milling chuck, is designed specifically to prevent cutter failure. The high-accuracy milling chuck has fully concentric clamping and runout of less than 0.0004″ (0.0102 mm) @ 4×D. It accepts standard Weldon flat end mills and requires no special grinding of the milling cutter.

Hydraulic expansion toolholders were developed by Schunk more than 35 years ago and have been continually improved to keep pace with advancements in machine technology and carbide tooling, Krolak said. The Tendo line features a high concentric clamping force, excellent vibration dampening and runout of less than 3 µm @ 2.5×D. All commercially available tools, with Weldon, Whistle notch or cylindrical shanks, can be clamped. Micron-accurate tool changes can be made in seconds.

As machining speeds increase and more difficult-to-machines alloys are introduced, machine shops need to continually re-evaluate their toolholding options. While highly secure toolholders typically cost more than their standard counterparts, the payback—in terms of the ability to machine at higher speeds and fewer scrapped parts and tools—can be substantial.

For high production tapping, the Speedsynchro tap holder features a programmable integrated transmission of 1:4.412 to optimize thread production on CNC machines with synchronous spindles. Combined with Softsynchro’s minimum length compensation, this allows high cutting speeds at a relatively low synchronous machine tool speed, compensating for synchronization errors during the threading process. Thread production cycle time is reduced by up to 40%, and the lower spindle speed can result in significant savings in energy costs.

For maximum tool security, the Pin-Lock Collet system is available as an option. This feature works with any Weldon shank tool and guarantees pullout protection.

The aerospace industry in particular has a big stake in secure toolholding, notes Jack Burley, vice president, sales and engineering for BIG Kaiser Precision Tooling Inc. (Hoffman Estates, IL). “A number of critical components are made from titanium, which is expensive and difficult to machine. If a cutting tool slips or pulls out, the results are extremely costly, in terms of both downtime and material loss,” Burley said.

Shops should be aware that heavy-duty machining is not the only cause of tool pullout, said Ryan Krolak, technical sales specialist for Schunk Inc. (Morrisville, NC): “It can also be the result of toolholders that do not offer concentric clamping,” Krolak said. “This often causes excessive runout, creating an uneven chip load on the cutter and premature tool failure. This shouldn’t have to be said, but it is important to make sure that all the running parameters are within the range of the material and the cutting tool being used.”'

”After more than four years, there have been no documented cases of a tool pullout with a secuRgrip holder,” said Chris Herdman, technical field support engineer for Rego-Fix. “The only mode of failure is that of the cutting tool itself.” Unlike other systems, secuRgrip does not require purchase of specially modified end mills, but rather can accept standard 0.5–1″ (12.7–25.4-mm) carbide or HSS end mills. The system maintains 0.0001″ runout and allows users to preset tool heights.

The new RF100 Sharp demonstrates smooth cutting action and chip removal and it is also a flexible end mill suitable for slotting, ramping, roughing, helical milling, finishing and trochoidal cutting. The smooth cutting action combined with the potential to be used in a wide variety of applications makes the new RF100 Sharp ideal for challenging material types.

From its extensive milling portfolio, the company will be giving a Mach show debut to the new RF100 Sharp Series of high-performance end mills — and this range will be put through its paces on the Grob to emphasise the performance characteristics of the end mills. Designed to address the issue of machining soft, tough and high-alloyed materials that create an issue with swarf clearance, the new RF100 Sharp Series is the manufacturer’s sharpest solid carbide milling tool to date.

The 4-flute end mills are suitable for machining steel, stainless steel, aluminium, aluminium alloys and other challenging materials. Available in three versions, an extra-long design long (DIN+) that is an extension on the long (DIN) version but has an even longer cutting edge and there is also a standard length end mill. The RF100 Sharp is offered in all common sizes up to 20 mm diameter. Depending upon the chosen diameter, the RF100 Sharp is supplied with an overall length from 50 to 104 mm with a flute length from 3 to 41 mm.

The RF100 Micro Diver Series is suitable for cutting materials up to 48HRC at depths up to 5XD. With a 40° helix angle to evacuate chips from the work area when conducting high-speed machining, the Series is available with a cutting diameter from 0.79 mm to 3.175 mm with a multitude of dimensional increments available.

From the 4th to the 8th of April, Guhring will return to the Mach exhibition at the Birmingham NEC. In Hall 19 on Stand 210, the cutting tool manufacturer will be introducing new product lines alongside established industry-leading ranges.

The Tendo holder contains an internal clamping piston that compresses hydraulic fluid into the oil chamber. The piston is manually actuated by an external clamping screw turned to a dead stop by an Allen key. A flexible sleeve immediately expands evenly against the tool shank, first centering the tool, then powerfully gripping it on the full surface. A length-setting screw can be actuated radially or axially for tool presetting.

As well as demonstrating an extensive range of innovative solid carbide tooling solutions, Guhring engineers will be on hand at Mach to discuss the scope of special tooling solutions that can be designed, developed, manufactured and trialled at the facility in Birmingham. Guhring UK has a team of expert engineers that can create productivity, cost, inventory and cycle time savings for UK manufacturers.

The Guhring stand at this year's Mach will showcase a complete range of threading, turning, drilling and milling tools, many of which will be live cutting at the trade fair on a Grob 5-axis machining centre that will be on the stand.

The optimal cutting conditions for the RF 100 5-Speed is applications on all tough materials up to 1200 N/mm2 and where a ramping angle of up to 10° is required. The solution is also perfect for slotting with cutting depths up to 1XD and helical milling. Whilst the RF 100 7-Speed is also the perfect choice for tough materials up to 1400 N/mm2, the seven fluted variant is also ideal for helical milling at in-feeds of up to 0.05XD ap per cycle.

Following the success of the Diver Series of end mills, Guhring has now extended this series to the micromachining sector with the new RF100 Micro Diver. The new micro-precision milling range is a universal tool for every material and application. Providing plunging and milling in a single tool, the new RF100 Micro Diver permits extreme cutting values with very highly cutting depths. Available in two variants, the 6808 and 6809, the RF100 Micro Diver features a symmetrical drilling face for stability when ramping and drilling, a new transition geometry to improve rigidity and an innovative flute form that further enhances rigidity and eliminates vibration.

TIR is less than 0.0001″ (0.0025 mm) even after thousands of tool changes, and powRgrip’s rigidity and high mass minimizes harmonics, extending tool life and reducing consumable costs, according to the company. The system has five sizes, resulting in only five machine inserts the operator would ever need to use every holder, and eliminating the need to purchase machine taper mounts.

Engineers at Rego-Fix agree that even with the highest clamping forces available, there are applications that require additional cutter retention measures. At IMTS 2012, Rego-Fix introduced the secuRgrip anti-pullout system, available for powRgrip, ER collet holders and milling chucks. A small, profiled steel locking key insert is installed in the ground flat of standard Weldon-shank cutting tools, locking the tool to the collet. A threaded friction bearing cap secures the collet in the holder and provides increased clamping force to prevent the collet from spinning.

Shrink-fit is based on the thermal expansion and contraction of metal, and uses an induction heating unit for assembly. The bore of the holder is initially slightly smaller than the outside diameter of the tool shank. When heated, the holder expands sufficiently to allow tool insertion. After cooling, contraction of the holder grips the cutting tool with up to 10,000 lb (4536 kg) of force. Tools can be changed in seconds, and operator training is minimal. As noted above, the Safe-Lock feature can be incorporated into Haimer shrink-fit toolholders.

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Also, on show at Mach will be the Ratio line of roughing end mills. With flat crested geometry and an optimised roughing profile that demonstrates 60 percent longer service life, the Ratio high-performance roughing cutter has several geometry adjustments aimed at providing performance. The Ratio increases material removal rates with its asymmetrical cutting flutes that reduce cutting pressure compared to smooth cutters.

In addition to the characteristics inherent the hydraulic expansion design, the Aviation toolholder employs a locking mechanism. A cutting tool with a standard Weldon shank is inserted into a special sleeve with a ball lock. The tool/sleeve assembly is then locked into place via set screws in the base of the toolholder. Finally, the holder is hydraulically actuated. As with other Tendo models, this process can be accomplished in seconds.

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Appearing alongside the new ranges will be established lines like the RF100 5-Speed and RF100 7-Speed solid carbide end mills. Developed for the machining of very tough materials, the RF100 5-Speed and RF100 7-Speed solid carbide end mills take cutting speeds and process reliability to a new level. The increased tooth number of the five-fluted 5-Speed and seven-fluted 7-Speed generate high metal removal rates with stable process reliability, even when processing the most difficult-to-machine materials. As part of the highly dynamic Guhring Trochoidal Cutting (GTC) series, the new RF100 5-Speed and RF100 7-Speed are perfect for machining tough stainless steels, special alloys and a wide variety of steel and cast-iron grades.

There are secure toolholders for a variety of cutting operations, including milling, drilling and tapping. For example, Emuge Corp. (West Boylston, MA) offers its highly rigid FPC Mill/Drill Chuck with three tons of traction force to hold a tool securely. This is the world’s only chuck with a 1:16 wormgear, according to Emuge. The collet-cone assembly absorbs virtually all vibration, for maximum vibration dampening. With a 3×D tool length, variation in concentricity is less than 3 µm, which extends tool life and substantially improves workpiece surface finishes. All models are balanced to G2.5, 20,000 rpm. In a speed comparison with four competing chuck designs, the FPC chuck enabled the feed rate to be increased by 30% with no loss in performance.

Krolak agreed that machining aerospace parts is particularly challenging. “Aircraft manufacturers have many applications with materials costing thousands of dollars and individual part cycle times exceeding 12 hours,” he said. “With this much invested in each machined component, tool failure is absolutely not an option.” To meet this need, Schunk recently introduced the Tendo Aviation toolholder for applications that require a secure tool that will not pull out.

Emuge also produces an extensive line of tapping toolholders. The Softsynchro rigid tap holder, with minimal length compensation, is said to reduce axial force to a fraction of that required in typical tapping applications, improving thread quality and extending tool life by up to 300%. Patented elastomer springs separate the spindle from the tap, absorbing excessive axial forces and providing the tap with a significant boost in tool life and performance. Torque from the spindle is transferred to the tap via ball bearings in precision-ground grooves, promoting precision micro-correction of lead errors in a rigid tapping cycle. The modular system is adaptable to any application requiring a length adjustment screw and interchangeability for different size taps.