According to the present disclosure, a cutting insert includes an upper surface having a polygonal shape and includes a corner, a side surface adjacent to the upper surface, a cutting edge and a protrusion. The cutting edge is located at a ridge part in which the upper surface intersects with the side surface and includes a corner part located at the corner. The protrusion is located on the upper surface. The protrusion includes a first protrusion on a bisector of the corner in a top view. The protrusion further includes a second protrusion adjacent to the first protrusion in a direction orthogonal to the bisector. The second protrusion is closer to the corner than the first protrusion in the top view.

The invention relates to a drill head comprising at least one surface, with a number of structural elements, wherein the structural elements are manufactured by an additive or primary forming manufacturing method. The invention further relates to a method for manufacturing such a drill head.

The invention relates to a drill head comprising at least one surface, with a number of structural elements, wherein the structural elements are manufactured by an additive or primary forming manufacturing method. The invention further relates to a method for manufacturing such a drill head.

A vibration cutting insert includes a top surface having a rake face and a breaker face, a first side surface, a second side surface, and a bottom surface. In a cross section which includes a bisector of an angle formed between a first ridgeline and a second ridgeline when viewed in a direction from the top surface toward the bottom surface, and which is parallel to the direction from the top surface toward the bottom surface, a rake angle formed between the rake face and a plane parallel to the bottom surface has a positive angle. The angle formed between the first ridgeline and the second ridgeline is an acute angle. The rake face constitutes a cylindrical surface. The breaker face constitutes a flat surface.

This invention provides a machine tool that, in addition to sequentially separating a chip generated from a workpiece in a reliable manner, improves the roundness of the finished workpiece and improves the visual appearance and roughness of a machined surface of the workpiece, and a control apparatus of the machine tool. A machine tool or a control apparatus thereof includes a vibration frequency setting unit for setting vibration frequency of the reciprocal vibration with respect to one relative rotation when machining a workpiece so that the intersections of paths of a cutting tool during forward movement and backward movement are dispersed on a circumferential surface of the workpiece.

This invention provides a machine tool that, in addition to sequentially separating a chip generated from a workpiece in a reliable manner, improves the roundness of the finished workpiece and improves the visual appearance and roughness of a machined surface of the workpiece, and a control apparatus of the machine tool. A machine tool or a control apparatus thereof includes a vibration frequency setting unit for setting vibration frequency of the reciprocal vibration with respect to one relative rotation when machining a workpiece so that the intersections of paths of a cutting tool during forward movement and backward movement are dispersed on a circumferential surface of the workpiece.

A cutting insert according includes a first surface and a cutting edge. The first surface includes a first inclined surface and a projection. The first inclined surface includes a first region located close to a first corner portion, a second region located close to a second corner portion, and a third region located between the first region and the second region. The projection includes a first projection located close to the first corner portion and a second projection located close to the second corner portion. A first top portion of the first projection is located closer to the first corner portion than a first boundary portion between the first region and the third region, and a second top portion of the second projection is located closer to the second corner portion than a second boundary portion between the second region and the third region.

A cutting insert according includes a first surface and a cutting edge. The first surface includes a first inclined surface and a projection. The first inclined surface includes a first region located close to a first corner portion, a second region located close to a second corner portion, and a third region located between the first region and the second region. The projection includes a first projection located close to the first corner portion and a second projection located close to the second corner portion. A first top portion of the first projection is located closer to the first corner portion than a first boundary portion between the first region and the third region, and a second top portion of the second projection is located closer to the second corner portion than a second boundary portion between the second region and the third region.

A controller controls a machine tool, which performs thread cutting for a workpiece, according to a machining program. The controller analyzes operating conditions of a cutting-up/cutting-in motion commanded in the machining program and inserts a cutting-up/cutting-in motion created based on the analyzed operating conditions into the thread cutting. In the insertion of the cutting-up/cutting-in motion into the thread cutting, a cycle including a cutting-in operation, a cutting-up operation for separating chips by raising the cutting tool for cutting in the radial direction of the workpiece, and an operation to cause the cutting tool to approach a start position of an immediately preceding cutting-up operation so as not to interfere with the workpiece is repeatedly performed.

A controller controls a machine tool, which performs thread cutting for a workpiece, according to a machining program. The controller analyzes operating conditions of a cutting-up/cutting-in motion commanded in the machining program and inserts a cutting-up/cutting-in motion created based on the analyzed operating conditions into the thread cutting. In the insertion of the cutting-up/cutting-in motion into the thread cutting, a cycle including a cutting-in operation, a cutting-up operation for separating chips by raising the cutting tool for cutting in the radial direction of the workpiece, and an operation to cause the cutting tool to approach a start position of an immediately preceding cutting-up operation so as not to interfere with the workpiece is repeatedly performed.