Cutting Insert Rake Surface Steps for Scratch-Free Chip Discharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cutting inserts can leave scratch marks on machined workpiece surfaces due to chip discharge issues, where the discharge speed and direction of chips near the corner cutting edge are similar to or lower than those near the main cutting edge, leading to contact with machined or unmachined surfaces.
Innovation Solution
A cutting insert design featuring a first step portion on the rake surface that reduces the discharge speed of chips near the corner cutting edge, altering the chip discharge direction to avoid contact with machined surfaces, and additional design features such as varying inclination angles and step portions to control chip flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the inclination angle of the rake surface is substantially constant in the extending direction of the main cutting edge, then the structure is simple and easy to manufacture, but the chip discharge speed and direction cannot be controlled, causing chips to contact machined surfaces and create scratch marks
Solution Approach 1:
The rake surface is divided into multiple segments with different inclination angles: a first rake surface portion with a first inclination angle, a second rake surface portion with a second inclination angle greater than the first, and a third rake surface portion connecting them. This segmentation allows different regions to control chip flow differently, preventing scratch marks while maintaining manufacturability.
Solution Approach 2:
Different portions of the rake surface are given different local properties (inclination angles) to achieve specific functions. The first rake surface portion has a smaller inclination angle to control chip discharge speed, while the second rake surface portion has a larger inclination angle to alter chip discharge direction, ensuring chips do not contact machined surfaces.
2Manufacturing precision
If the chip discharge speed near the corner cutting edge is similar to or lower than near the main cutting edge, then the cutting process is stable, but the chips contact machined or unmachined surfaces causing scratch marks
Solution Approach 1:
The inclination angle parameter of the rake surface is changed across different portions. The first rake surface portion has a first inclination angle that controls chip discharge speed, while the second rake surface portion has a second inclination angle (greater than the first) that alters chip discharge direction. This parameter variation ensures chips are discharged away from machined surfaces without compromising cutting stability.
3Strength
If the main cutting edge extends to intersect the reference surface, then the cutting capability is enhanced, but the corner cutting edge geometry becomes more complex requiring step portions
Solution Approach 1:
The rake surface is segmented into three distinct portions (first, second, and third rake surface portions) with different inclination angles and functions. The first rake surface portion connects to the flat drag, the second rake surface portion connects to the main cutting edge, and the third rake surface portion connects to the corner cutting edge. This segmentation manages the geometric complexity while maintaining enhanced cutting capability.
Solution Approach 2:
Different local geometries are provided for different cutting functions. The first rake surface portion has a first inclination angle for controlling chip discharge from the flat drag region, while the second rake surface portion has a second inclination angle for the main cutting edge region. This local differentiation allows the main cutting edge to extend effectively while managing overall geometric complexity.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A cutting edge has a corner cutting edge, a flat drag, and a main cutting edge. The rake surface has a first rake surface portion continuous with the flat drag, a second rake surface portion continuous with the main cutting edge, and a third rake surface portion continuous with the corner cutting edge and located between the first rake surface portion and the second rake surface portion. The first rake surface portion has a first inclined surface inclined at a first angle with respect to the reference surface. The second rake surface portion has a second inclined surface inclined at a second angle greater than the first angle with respect to the reference surface. The first end portion and the second end portion are higher than the reference surface in a direction perpendicular to the reference surface, and the main cutting edge extends so as to intersect the reference surface when viewed in a direction parallel to the reference surface. A first step portion rising from the third rake surface portion and continuous with the first rake surface portion is provided on the rake surface.