The new all-electric HTA hone from Sunnen brings increased part capacity and stroker torque to applications such as bore resurfacing of hydraulic cylinders, extruder barrels and die casting shot tubes or manufacture of gas flow meter tubes and repair of actuators for construction, mining, farming and forestry equipment. The machine is available in two standard model sizes: the HTA-2100 for 6.9-foot (2.1 m) part lengths and the HTA-4100 for 13.5-foot (4.1 m) part lengths, accommodating true 2- or 4-meter parts. Both models handle parts with bore ID of 2.5 to 21 inches (63.5 - 533 mm) and maximum part OD of 24 inches (610 mm), and part weights to 8000 pounds (3628.7 kg). The HTA can also be custom-configured for part lengths up to 65.6 feet (20 m), or with a powered section only for unhindered part lengths. Stroker torque capability has been increased by 35 percent over the previous HTA model via a heavy-duty stroker drive gearbox. Width of the steel-impregnated polyurethane belt has been increased from 0.9 inches to 1.9 inches (22 mm to 50 mm), providing a 20:1 safety factor. "The new HTA takes what was already an excellent machine platform and makes it even more robust without raising the cost," said Phil Hanna, machinery production manager for Sunnen. "With installations in the U.S., Europe, South America, Australia, and Africa, this machine has proven to be popular all over the world, accounting for nearly 60 sales since its introduction in mid-2009, and it has been chosen as the primary tube hone for Caterpillar's Dealer Services network worldwide."
The HTA hone is suitable for resurfacing and repair work where light-duty stock removal up to 0.030 inches (0.76 mm) is needed to oversize deeply scratched bores. It is designed for optimum performance with Sunnen ANR275 tooling and abrasives, sold with matching coolants and gauging as part of the machine package. An electronically controlled, 3-hp (2.24 kW), AC gear motor powers the spindle at 20-300 rpm, while the servo-driven stroking system has a speed range of 5‑90 ft/min (1.52-27.4 m/min). The all-electric machine eliminates the noise, leaks, valve adjustments and performance variability inherent to hydraulic systems. Utilized for flow-tube weld cleanup, the HTA hone is ergonomically designed with a moveable operator station and a modular work holding system for rapid setups. It includes a 55-gallon (208 L) coolant reservoir and paper-media coolant filtration unit for better coolant management. Set on casters for easy maintenance, the coolant tank tucks under the machine frame to conserve floor space.
The HTA system includes high-end features, such as Siemens drives and PLC-control with touch-screen HMI for setting all machine parameters, including stroke reversal point, spindle/stroking speeds and crosshatch angle calculation. The control features a digital load meter to determine areas of bore tightness, with capability for dwelling the tool in multiple areas to correct part geometry. Other advanced features include automatic tool tensioning, set through the PLC.