The HydroForce HT™ universal hydraulic chuck from Kennametal reportedly has among the highest levels of transmittable torque available thanks to its compact design.

Universal Chuck Prolongs Tool Life for Milling, Drilling

April 23, 2015
Kennametal hydraulic workholding tool simplifies shops’ inventory choices Maximum torque, resisting bending loads Strong connections, and high stiffness Two sizes cover all rotating tooling

The HydroForce HT universal hydraulic chuck introduced recently by Kennametal has a front-wall cross-section that is 40% thicker than previous designs, making it a cost-effective workholding device that simplifies shops’ inventory choices and maximizes tool life for milling, drilling, reaming, and other rotating applications.

With among the highest levels of transmittable torque available thanks to its compact design, HydroForce HT also provides increased rigidity necessary that improves cutting parameters. Clamping force reportedly is up to three times better than regular hydraulic chucks. With improved vibration dampening, run-out is three microns at 2X diameter overhang, according to Kennametal. Balance quality of G2.5 is achieved at speeds up to 25,000 rpm.

The performance standards achievable in the high-torque chuck means that only two sizes are required to cover all rotating tooling tasks, according to Kennametal. Direct clamping is available for 20 and 32 mm (0.75 and 1.5 in.) diameters and reducer sleeves are applied for all other diameters.

When machining tough materials (e.g., titanium), cutting speeds are relatively low due to thermal effects on cutting tools. In response, machine-tool builders have improved stiffness and dampening on spindles and machine structures to provide very high torque at low rotational speeds.

In such cases, the HydroForce HT universal chuck works directly with the Kennametal KM4XTM spindle connection to transmit higher levels of torque and maximize resistance to bending loads. In end-milling applications, where projection lengths are typically greater, the limiting factor is the spindle interface’s bending capacity.

For example, an indexable helical cutter with 250 mm (9.84 in.) projection from spindle face, 80 mm (3.15 in.) in diameter generates 4,620 Nm (3,407.5 ft. lbs.) of bending moment and less than 900 Nm (663.8 ft. lbs.) of torque. Often, bending moment boundaries are exceeded far before torque levels.

The combination of the KM4XTM system’s high clamping force and interference level promote strong connections and extremely high stiffness and bending capacity that improve performance in titanium machining. KM4X and HydroForc Ht together overcome the limitation on bending capacity found in other connections. Maximum available spindle power and torque are brought to bear every time in critical operations like milling of high-strength materials.

Kennametal's hydraulic chucks are among the world's leading toolholder systems. Other choices include BASIC-Line expansion chucks, TREND-Line, HP Line with radial tool-length adjustment, and SLIM-Line for long L to D ratios. The hydraulic chucks are characterized by low maintenance costs. All hydraulic chucks are equipped with central coolant for use with through-coolant or non-through-coolant tools, and can also be applied in minimum quantity lubrication (MQL) situations.

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