A rotatable cutting tool for machining of a honeycomb core includes a front end; a rear end; a peripheral surface extending between the front and rear ends; a set of helical flutes formed in the peripheral surface at a first helix angle 45°≤α≤65°, having a first depth; and a set of helical ridges. At least one helical groove formed in the peripheral surface at a second helix angle 90°<β≤100°, has a second depth, which is smaller than the first depth. The at least one helical groove intersects the helical ridges so that a plurality of cutting teeth are formed on each helical ridge. Each cutting tooth includes a second ridge formed in a transition between two lands, a cutting edge and a clearance edge join in a tooth tip constituting the radially outermost point of the cutting tooth.

In an aspect, a rotating tool includes a main body having a rod shape and extending along a rotation axis. The main body includes a first end, a second end, a twisted cutting edge located at a side of the first end, a twisted flute, a reverse twisted cutting edge located closer to the second end than the twisted cutting edge, and a reverse twisted flute. The reverse twisted flute is connected to the twisted flute. The twisted cutting edge includes a first part having a length from the rotation axis decreasing as approaching toward the second end.

A tool for the rotary and cutting machining of workpieces includes a plurality of blades arranged on the tool body and arranged in blade arrangements, and having a securing element that secures the blade arrangements to the tool body so that the blades cannot detach from the tool body during operation. The tool body is produced from plastic. The blades are incorporated into the tool body and the securing element provides a securing strip that is incorporated into the tool body and partially encloses the blade arrangements.

Disclosed is a helical milling tool with forward-backward feeding, the tool including a cutting portion, a neck portion and a handle portion, which are successively connected to each other; wherein the cutting portion includes a front-end cutting section, a circumferential cutting section and a back-end cutting section, which are connected successively to each other; the front-end cutting section is of an end milling cutter structure or a drill bit structure; the circumferential cutting section is of a cylindrical shape and is of a circumferential milling cutter structure; and the back-end cutting section is of a frustum-shaped. The tool can avoid defects such as layering and tearing, which go beyond processing requirements in a composite material, improve the processing quality, save on costs, simplify the processing process, improve the production efficiency and prolong the service life of the tool.

Disclosed is a method for helical milling with forward-backward feeding, including the following steps: determining the aperture D1 of a pre-processing hole; according to a final aperture D of a through-hole to-be-processed and the aperture D1 of the pre-processing hole, selecting a suitable tool; clamping the workpiece to-be-processed and the tool; the tool processes the pre-processing hole with forward feeding with aperture D1, D1<D, until the back-end cutting section of a cutting portion of the tool extends out of an outlet side; adjusting eccentricity of the tool one or more times, backward feeding from the outlet side, and using the back-end cutting section of the cutting portion of the tool to helical mill a through-hole with the aperture D. The present disclosure can avoid defects such as the delamination and tearing of a composite beyond processing requirements, improve the processing quality, save costs, simplify the processing process, increase the production efficiency of the tool and prolong the service life of the tool.

A high frequency vibration spindle system with non-contact power transmission and a method for manufacturing a restraining member used therein are disclosed. The high frequency vibration spindle system comprises: an electric power transmission device including a first induction module and a second induction module, wherein the second induction module is disposed at either a spindle or a toolholder and is adapted to receive an electric power from the first induction module in a non-contact electromagnetic induction manner; a transducer adapted to vibrate the tool and disposed at the toolholder and electrically connected with the second induction module to receive the electric power; and-a restraining member located between the first induction module and the second induction module. With the restraining member, the structural strength and stability of the second induction module can be improved, thereby increasing the maximum rotational speed of the high frequency vibration spindle system.

The present invention provides a material for built up edge formation having a resin block containing a high molecular weight compound having a weight average molecular weight of 5×10.sup.4 or higher and 1×10.sup.6 or lower, a medium molecular weight compound having a weight average molecular weight of 1×10.sup.3 or higher and lower than 5×10.sup.4, and a carbon.

The present invention is aimed to provide a carbon fiber reinforced resin processed product which is almost free from the problems described above on a processed surface subjected to cutting or the like and has an end surface where generation of a burr is suppressed, has favorable surface properties, and surface nature, and particularly smoothness is excellent; and provides a carbon fiber reinforced resin processed product having an end surface which has fibers and a resin, wherein the end surface has a surface roughness (Rz) within a range from 5 μm to 50 μm.

A rotating tool according to one aspect includes a body that extends from a first end to a second end, and the body includes a second helical cutting edge, a second helical flute, a first helical cutting edge, and a first helical flute. The body further includes a reversely-helical cutting edge and a reversely-helical flute from the second helical flute. The reversely-helical cutting edge and the reversely-helical flute are helical reversely to the second helical flute from the second helical flute to the second end, and the reversely-helical flute extends along the reversely-helical cutting edge. The reversely-helical cutting edge is positioned intersecting with an extended line of a trace of the first helical cutting edge and not intersecting with an extended line of a trace of the second helical cutting edge.

A rotary cutting tool includes a main body and a shank. The main body has a tip end. The shank is continuous with the main body on the side opposite to the tip end. The main body is provided with a first cutting edge having a positive twist angle, and a second cutting edge having a negative twist angle and separated from the first cutting edge. Each of the first cutting edge and the second cutting edge extends continuously from the tip end to the shank.