A machine tool comprises first and second support arms, and a rigid structure which couples the first support arm to the second support arm. A first rotary drive is operable to rotate the first support arm and the rigid structure relative to each other about a first rotational reference axis, and a second rotary drive is operable to rotate the second support arm and the rigid structure relative to each other about a second rotational reference axis, wherein the first and second rotational reference axes are parallel and spaced apart by a fixed distance. A control arrangement is configured to control the first and second rotary drives such that a workpiece mount carried by the second support arm follows a predetermined path relative to a tool mount carried by the first support arm in a plane perpendicular to the rotational reference axes.

A machine tool comprises first and second support arms, and a rigid structure which couples the first support arm to the second support arm. A first rotary drive is operable to rotate the first support arm and the rigid structure relative to each other about a first rotational reference axis, and a second rotary drive is operable to rotate the second support arm and the rigid structure relative to each other about a second rotational reference axis, wherein the first and second rotational reference axes are parallel and spaced apart by a fixed distance. A control arrangement is configured to control the first and second rotary drives such that a workpiece mount carried by the second support arm follows a predetermined path relative to a tool mount carried by the first support arm in a plane perpendicular to the rotational reference axes.

An abrasive article includes a first abrasive element, a second abrasive element, a resilient element having first and second major surfaces, and a carrier. The first element and the second abrasive element each comprises a first major surface and a second major surface. At least the first major surfaces of the first and second abrasive elements comprise a plurality of precisely shaped features. The abrasive elements comprise substantially inorganic, monolithic structures.

An abrasive article includes a first abrasive element, a second abrasive element, a resilient element having first and second major surfaces, and a carrier. The first element and the second abrasive element each comprises a first major surface and a second major surface. At least the first major surfaces of the first and second abrasive elements comprise a plurality of precisely shaped features. The abrasive elements comprise substantially inorganic, monolithic structures.

A gear-grinding multilayer grindstone includes: a first thread-shaped grindstone and a second thread-shaped grindstone that are fixed to each other, such that the first and second thread-shaped grindstones have a rotational axis that is common to the first and second thread-shaped grindstones; and a thread-shaped groove that is provided in a first outer circumferential surface of the first thread-shaped grindstone and a second outer circumferential surface of the second thread-shaped grindstone. The thread-shaped groove extends continuously over the first outer circumferential surface and the second outer circumferential surface. The second thread-shaped grindstone is constituted by abrasive cloths that are laminated on each other, and has a higher elasticity than the first thread-shaped grindstone.

A combined grinding wheel for ultrasonic machining and the determine method thereof. The combined grinding wheel for ultrasonic machining comprises: an outer grinding ring, an upper end thereof having a center taper hole and a plurality of outer grinding ring water holes located in a circumferential outer side of the center taper hole; a connecting taper shank, the upper end thereof having a taper shank extending into an outer grinding ring cavity from the center taper hole and matching the tapered surface of the center taper hole; a connecting flange, located outside the shank portion and fixed on the inner wall of the upper end of the outer grinding ring cavity, and having a center tapered through hole; and an inner vibration unit, having a tapered surface matching the tapered surface of the center tapered through hole and a center hole connected with the connecting taper shank by means of a screw.

A combined grinding wheel for ultrasonic machining and the determine method thereof. The combined grinding wheel for ultrasonic machining comprises: an outer grinding ring, an upper end thereof having a center taper hole and a plurality of outer grinding ring water holes located in a circumferential outer side of the center taper hole; a connecting taper shank, the upper end thereof having a taper shank extending into an outer grinding ring cavity from the center taper hole and matching the tapered surface of the center taper hole; a connecting flange, located outside the shank portion and fixed on the inner wall of the upper end of the outer grinding ring cavity, and having a center tapered through hole; and an inner vibration unit, having a tapered surface matching the tapered surface of the center tapered through hole and a center hole connected with the connecting taper shank by means of a screw.

A bonded abrasive wheel is disclosed comprising a plurality of abrasive particles disposed in a binder, a first grinding surface, a second surface opposing the first grinding surface, and an outer circumference. The wheel comprises a rotational axis extending through a central hub and a circuit configured as a Radio Frequency Identification (RFID) unit coupled to the abrasive wheel. The circuit comprises an antenna configured to communicate with one or more external devices and comprising a first end and a second end, wherein antenna has a radius of curvature about an axis along at least a portion thereof such that the first end is disposed adjacent to but is spaced from the second end, and an integrated circuit (IC) operably coupled to the antenna and configured to store at least a first data.

A bonded abrasive wheel is disclosed comprising a plurality of abrasive particles disposed in a binder, a first grinding surface, a second surface opposing the first grinding surface, and an outer circumference. The wheel comprises a rotational axis extending through a central hub and a circuit configured as a Radio Frequency Identification (RFID) unit coupled to the abrasive wheel. The circuit comprises an antenna configured to communicate with one or more external devices and comprising a first end and a second end, wherein antenna has a radius of curvature about an axis along at least a portion thereof such that the first end is disposed adjacent to but is spaced from the second end, and an integrated circuit (IC) operably coupled to the antenna and configured to store at least a first data.

A high-rotational speed cup-shaped grinding wheel includes an annular base, several blades and a flow splitting structure. The blades are fixed on a side of the base at an interval in a circumferential direction to form a blade ring. The side of the blade ring away from the base forms an annular working surface, and two adjacent blades are spaced apart from each other to form a water passage channel for delivering cooling water to the working surface. The flow splitting structure is fixed on the blade ring and splits the cooling water into two branches, where a first branch delivers the cooling water to an outer area of the working surface, and a second branch delivers the cooling water to an inner area of the working surface, and then delivers the cooling water from an inner area of the working surface to an outer side area thereof.