Cutting insert, cutting tool, and method of manufacturing machined product

Abstract

A cutting insert of an embodiment includes an upper surface including a first upper cutting edge and a second upper cutting edge, a lower surface including a first lower cutting edge and a second lower cutting edge, and a side surface. The side surface includes a first surface extending from the second upper cutting edge, a second surface extending from the first lower cutting edge, a third surface extending from the first upper cutting edge, and a fourth surface extending from the second lower cutting edge. The first surface and the fourth surface are parallel to a central axis. The second surface is inclined so as to depart from the central axis as going from the lower surface toward the upper surface. The third surface is inclined so as to depart from the central axis as going from the upper surface toward the lower surface.

1 . A cutting insert comprising:
 an upper surface comprising a first side part and a second side part;   a lower surface comprising a third side part and a fourth side part;   a first lateral surface located between the first side part and the third side part;   a second lateral surface located between the second side part and the fourth side part;   an upper edge located at the first side part and comprising a first upper edge and a second upper edge; and   a lower edge being located at the third side part and comprising a first lower edge and a second lower edge, wherein a central axis is an imaginary line through a center of the upper surface and a center of the lower surface,   the first lower edge is located below the second upper edge and the second lower edge is located below the first upper edge,   the first lateral surface comprises:
 a first region angled in a first direction relative to the central axis, and 
 a second region angled in a second direction relative to the central axis, 
   the second direction is different from the first direction, and   the second lateral surface comprises a flat region parallel to the central axis.   
     
     
         2 . The cutting insert according to  claim 1 , wherein
 the first region is separated from the third side part, and the second region is separated from the first side part.   
     
     
         3 . The cutting insert according to  claim 1 , wherein
 the lateral surface further comprises:
 a third region angled relative to the first region, and 
 a fourth region angled relative to the second region, and 
   the first region is located between the second region and the third region,   the second region is located between the first region and the fourth region.   
     
     
         4 . The cutting insert according to  claim 3 , wherein
 the third region and the fourth region are parallel to the central axis.   
     
     
         5 . The cutting insert according to  claim 3 , wherein
 the third region and the fourth region are connected to the upper surface and the lower surface.   
     
     
         6 . The cutting insert according to  claim 3 , wherein
 each of the first region, the second region, the third region and the fourth region comprises a flat surface.   
     
     
         7 . The cutting insert according to  claim 3 , wherein
 the first region and the second region are directly adjacent to the third region and the fourth region.   
     
     
         8 . A cutting insert comprising:
 an upper surface comprising a first side part;   a lower surface comprising a second side part;   a lateral surface located between the first side part and the third side part;   an upper edge located at the first side part and comprising a first upper edge and a second upper edge; and   a lower edge being located at the second side part and comprising a first lower edge and a second lower edge, wherein   a central axis is an imaginary line through a center of the upper surface and a center of the lower surface,   the first lower edge is located below the second upper edge and the second lower edge is located below the first upper edge,   the lateral surface comprises:
 a first region, 
 a second region, 
 a third region located between the first region and the second region, and angled relative to the first region, and 
 a fourth region located between the third region and the second region, and angled relative to the second region, 
   the third region is angled in a first direction relative to the central axis,   the fourth region is angled in a second direction relative to the central axis, and   the second direction is different from the first direction.   
     
     
         9 . The cutting insert according to  claim 8 , wherein
 the third region is separated from the second side part, and the fourth region is separated from the first side part.   
     
     
         10 . The cutting insert according to  claim 8 , wherein
 the first region and the second region are parallel to the central axis.   
     
     
         11 . The cutting insert according to  claim 8 , wherein
 the first region and the second region are connected to the upper surface and the lower surface.   
     
     
         12 . The cutting insert according to  claim 8 , wherein each of the first region, the second region, the third region and the fourth region comprises a flat surface. 
     
     
         13 . The cutting insert according to  claim 8 , wherein
 the third region and the fourth region are directly adjacent to the first region and the second region.   
     
     
         14 . A cutting insert comprising:
 an upper surface comprising a first side part;   a lower surface comprising a second side part;   a lateral surface located between the first side part and the third side part;   an upper edge located at the first side part and comprising a first upper edge and a second upper edge; and   a lower edge being located at the second side part and comprising a first lower edge and a second lower edge, wherein   a central axis is an imaginary line through a center of the upper surface and a center of the lower surface,   the first lower edge is located below the second upper edge and the second lower edge is located below the first upper edge,   the lateral surface comprises:
 a first region angled in a first direction relative to the central axis, and 
 a second region angled in a second direction relative to the central axis, 
   the second direction is different from the first direction, and   an upper end of the second region is closer to the first side part than an upper end of the first region.   
     
     
         15 . The cutting insert according to  claim 14 , wherein
 the second region is separated from the second side part, and the first region is separated from the first side part.   
     
     
         16 . The cutting insert according to  claim 14 , wherein
 the lateral surface further comprises:
 a third region angled relative to the first region, and 
 a fourth region angled relative to the second region, and 
   the first region is located between the second region and the third region,   the second region is located between the first region and the fourth region.   
     
     
         17 . The cutting insert according to  claim 16 , wherein
 the third region and the fourth region are parallel to the central axis.   
     
     
         18 . The cutting insert according to  claim 16 , wherein
 the third region and the fourth region are connected to the upper surface and the lower surface.   
     
     
         19 . The cutting insert according to  claim 16 , wherein each of the first region, the second region, the third region and the fourth region comprises a flat surface. 
     
     
         20 . The cutting insert according to  claim 16 , wherein
 the first region and the second region are directly adjacent to the third region and the fourth region.