FR Series of machines to manufacture gears for robots

These new products, marketed as the ‘FR Series’, respond to the rapidly growing need for highly precise and efficient manufacturing of precision reduction gears for robots. The full-fledged launch will begin in August 2020, with the unveiling at an online seminar scheduled for September.

The name ‘FR Series’ is derived from Fine Pitch for Robot, Reducer. The market expansion for industrial and life support robots in recent years has led to a sharp rise in demand for the high precision, small module gears inside the precision reduction gears used in the joints of these robots. Two types of gears are used in these reduction gears (an external tooth gear and an internal tooth gear), and MHI Machine Tool has added to its lineup a hobbing machine to create the external gear, and a shaping machine to make the internal gear.

In contrast with conventional mass-production gears typically used in the automotive industry, which have modules (gear tooth sizes) of 1 to 4 and accuracy requirements of ISO class 8 or 9, gears for robots require greater precision, with modules of 1 or below, and an ISO class of 3 to 6. The FR Series was specifically designed to meet these demands.

MHI Machine Tool's hobbing machines utilise direct-drive motors for both the main spindle to which the cutting tool (hob) is attached and the work table spindle holding the workpiece, along with advanced control technology. By limiting the machine tool error to the greatest extent possible, this system achieves a pitch error of just one micrometer.

Compared with precision gear cutting, accuracy has been raised three classes (from around ISO 6 to ISO 3). Also, the fast cutting speed with up to 8,000rpm (revolutions per minute) shortens the processing time by around a third, contributing to greater productivity.

The shaping machines utilise high precision worm gears for the cutter head and work table that comprise the core components. Further, strict management values in the machine's assembly precision have raised the precision class for the gear working by two levels (from around ISO 7 to ISO 5), providing high gear precision.

MHI Machine Tool is utilising its strength in manufacturing both gear cutting machines and cutting tools to not only offer machines to manufacture the high-precision gears used in precision reduction gears for robots, but with its comprehensive solutions for gear machining, including cutting tools to ensure optimal cutting, processing know-how, and automated systems, is contributing to the manufacturing of high-precision gears.