Cutting insert, cutting tool including same, and method for manufacturing machined product

An insert, comprising:

• a first face;
• a second face located opposite to the first face;
• a third face located between the first face and the second face;
• and
• a cutting edge located on an intersection of the first face and the third face, wherein
• the first face comprises:
• a first region inclined so as be close to the second face as being separated away from the cutting edge;
• and
• a second region that is located on an inner side with respect to the first region and inclined so as to be separated away from the second face as being separated away from the first region,
• a virtual straight line orthogonal to the cutting edge is set as a first virtual straight line in a front view of the first face,
• a ten-point average of roughness of the first region in a direction along the first virtual straight line is expressed by Rz1a and a ten-point average of roughness of the first region in a direction along the cutting edge is expressed by Rz1b,
• the Rz1a is larger than the Rz1b,
• a ten-point average of roughness of the second region in the direction along the first virtual straight line is expressed by Rz2a and a ten-point average of roughness of the second region in the direction along the cutting edge is expressed by Rz2b, and
• the Rz2a is larger than the Rz2b, and
• the Rz2b is smaller than the Rz1b.

An insert, comprising:

• a first face;
• a second face located opposite to the first face;
• a third face located between the first face and the second face;
• and
• a cutting edge located on an intersection of the first face and the third face, wherein
• the first face comprises a first region inclined so as be close to the second face as being separated away from the cutting edge, a virtual straight line orthogonal to the cutting edge is set as a first virtual straight line in a front view of the first face,
• a ten-point average of roughness of the first region in a direction along the first virtual straight line is expressed by Rz1a and a ten-point average of roughness of the first region in a direction along the cutting edge is expressed by Rz1b,
• the Rz1a is larger than the Rz1b,
• a virtual straight line orthogonal to the cutting edge is set as a second virtual straight line in a front view of the third face,
• a ten-point average of roughness of the third face in a direction along the second virtual straight line is expressed by Rz4a, and
• the Rz4a is smaller than the Rz1a.