Renishaw’s RESOLUTE™ supports ITRI breakthrough in multi-axis rotary table design

By Niraj M Wanikar, Chief Editor, CNCTimes.com, 2015-10-15 15:12:50

The term ‘5-axis machining' typically refers to the ability of a CNC machine to move a part or tool on five separate axes at the same time. The machine tool has an indispensable role in modern industry and has recently benefited from the popularity of 5-axis machining centres that greatly enhance flexibility in product design, by enabling precise and detailed machining of complex mass-produced parts.

Everyday items such as smartphone cases and shells for tablet PCs, alongside other metal bodies for consumer electronics, are processed with these advanced machine tools. As multi-axis machine tool technology matures, demand for rotary tables with enhanced accuracy and rotational speed is rising. Taiwan Industrial Technology Research Institute (ITRI) has addressed this market trend by developing an advanced dual-axis rotary table with integrated Renishaw RESOLUTE absolute rotary encoders and Panasonic serial communication protocols for direct interfacing with Panasonic drives and controllers.

Rotary tables and machine tools

The rotary table is a key part of the machine tool, particularly for complex machine tool operations such as drilling, milling and turning. Machine tool manufacturers have adapted their product offering to suit the processing requirements of customers. Rotary tables allow scalable processing by adding a fourth or fifth axis to the traditional three axes of a CNC machining centre. Modern 3-axis machining centres require multiple setups each with its own fixturing requirements, as the workpiece is static, whereas 5-axis machines enable the user to effectively machine on five sides of a workpiece (top, front, rear, left and right) in one clamping, which significantly reduces total cycle and setup times. On-machine probing may also be applied to reduce set-up time, enhance automation and maintain the accuracy of critical components.

ITRI's senior engineer on the project, Mr Kuan-wen Chen, outlines their motivation: “Rotary tables on the market are either uniaxial or biaxial (dual-axis) and comprise a workpiece table, external housing, main bearing, servo motor and drive components, an encoder and braking system. In order to reduce costs, all of the components except the servo motor and encoder were either developed in-house or locally procured. After several years' development, the overall build cost of the current ITRI design, when compared with competing international brands, is over 50% lower and our ultimate goal now is to transfer these technologies and solutions to local manufacturers to help them develop competitive rotary tables with high cost-performance (CPI).”

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