Abstract:
To improve a metal-cutting process for machining cylindrical contours, especially eccentric cylindrical contours on a workpiece mounted to rotate about a longitudinal axis, especially with eccentric crankshaft bearings using a lathe tool, producing a finished contour that either has end measures of satisfactory surface quality or has oversize for finish machining such as grinding or dressing, so that while maintaining or enhancing surface quality and maintaining or enhancing dimensional accuracy, machining times are reduced and overall economic efficiency is raised, the invention proposes that the tools tipped with cutting inserts, especially throw-away cutting inserts, are engaged successively or even simultaneously and that at least one part of the cutting inserts is guided in relation to the workpiece at an effective cutting angle ( gamma f) between -5 DEG and +5 DEG and/or a positive tool back wedge angle ( gamma p).
Abstract:
This invention relates to a negative type throwaway tip in a square flat plate form in which each of ridges at which the upper and lower surfaces intersect four side surfaces thereof at right angles respectively is adapted to work as a primary cutter and, at one longitudinal end of each primary cutter, a secondary relief surface is formed in such manner that it increasingly largely recedes from an imaginary extended line of a primary cutter as it advances from a midpoint of a cutter toward the corner of the upper or lower surface. The ridge at which the end on the corner side of a secondary relief surface intersects a side surface works as a secondary cutter. When said throwaway tip is fixed to the tool proper so that either upper or lower surface thereof is adapted to work as an outer peripheral relief surface directed toward the outer periphery of the tool and to gradually sharply incline to the outer periphery of the tool in the radial direction as it extends from the forward end of the tool along the axial direction toward the rear end, and so that a rake angle in the axial direction of a primary cutter directed toward the rotational direction of the tool at the outer peripheral side of the tool is made negative, a front relief angle is provided to a secondary cutter continuing to the forward end of the primary cutter.
Abstract:
A tool for machining by chip removal workpiece surfaces to be dressed, such as a milling head rotatable around an axis, has several blanking dies (3) mounted on its front face (2). In order to obtain a workpiece (19) with a high quality surface with relatively long service life of the tool, each blanking die (3) has four main cutters and four dressing cutters (15, 10A). The blanking dies have each four basically trapezoidal front faces (13A, 14A; 13B, 14B) mutually inclined in pairs in relation to the side faces (9). The long edges formed by the front and side faces together are provided each with a bezel (14A, 14B), the edges of the body formed by contiguous front faces of the blanking die in the area of the bezels forming the main cutters (15). The short edges formed by the front and side faces together are convex and form the dressing cutters (10A). The corners (12A, 12B) of the side faces of the blanking dies preferably form rhomboid parallelograms.
Abstract:
An indexable cutting insert has a first corner edge (17) configured to form a front tip of a cutting edge portion (16) configured to project furthest in the direction of an axis of rotation of an end mill tool receiving the insert. A major cutting edge (18) is descending to come closer to the lower surface of the insert along its extension away from the first corner edge (17). The minor cutting edge (20) extends from the first corner edge (17) while descending from a point (40) of the cutting edge portion (16) most distant to the lower surface (8) all the way to an inner corner (23) of the insert and has a length of 80%-95% of the length of the major cutting edge (18) including a second corner edge (19) in a side elevation view of the cutting insert.
Abstract:
A double-sided milling insert (30;30') for high feed milling of metal workpieces with a trigonal basic shape and comprising upper (31) and lower (32) faces facing in opposite directions and convex clearance surfaces (33) extending between the upper (31) and lower (32) faces. Each one of the faces comprises a recessed support surface (34A,34B), the support surfaces (34A,34B) being substantially parallel to each other, and having a cavity (35) therein for receiving a fastening means. Intersections of the convex clearance surfaces (33) with the upper and lower faces (34A,34B) form convex cutting edges (37A,37B;37A',37B') when seen in a plan view (fig. 1A) and a rake face (38) is provided adjacent the convex cutting edges (37A,37B,37a',37b'). Each convex cutting edge (37A,37B,37a',37b') is concave when seen in a side view (Fig. 1B) and comprises a substantially straight cutting edge portion (39A,39B;39A',398') on each side of a curved cutting edge portion (40A,40B;40A',40B') when seen in a plan view (fig 1a). A milling tool with a plurality of such inserts and a method of high feed milling using this tool are also disclosed.