Four-Way Positive Cutting Insert for Small-Diameter Shoulder Milling
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Solution Overview
Problem
Current single-sided two-way indexable inserts are disadvantaged in small diameter applications due to limited indexable positions and wear issues, particularly in 90° shoulder milling operations, where four-way indexable inserts are not commonly used due to concerns about wear on cutting edges used as wipers.
Innovation Solution
A single-sided four-way indexable cutting insert with a basic square shape and specific design features, including an unground lower sub-surface, overhanging portions, and a volume ratio that minimizes material usage, allowing for four indexable positions and reduced wear, making it competitive with solid end mills in small diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If single-sided two-way indexable inserts are used for small diameter applications, then the insert structure is simple and easy to manufacture, but the number of indexable positions is limited and wear issues occur
Solution Approach 1:
The insert is designed with four distinct indexable positions instead of two, segmenting the cutting edge usage into four separate stages. This allows the same insert body to provide multiple cutting edges that can be sequentially used, effectively doubling the indexable positions while maintaining the same basic insert structure and manufacturing complexity
Solution Approach 2:
The insert design enables a single insert to perform multiple functions through four indexable positions, allowing the same hardware component to provide extended operational life and versatility. The insert can be indexed multiple times to utilize different cutting edges, making one insert equivalent to multiple inserts in terms of functional capability
2Adaptability or versatility
If four-way indexable inserts are used in 90° shoulder milling operations, then the number of indexable positions increases, but wear on cutting edges used as wipers becomes a problem
Solution Approach 1:
The insert design applies different functional qualities to different regions of the cutting edge. Specific portions of the cutting edge are optimized for main cutting operations while other portions are designed for wiper functions, allowing each region to perform its designated function with appropriate wear characteristics. This local differentiation enables four indexable positions without compromising reliability
Solution Approach 2:
The design allows the insert to be used through four indexable positions, effectively recovering and reusing the insert multiple times. After each cutting edge is worn, the insert is indexed to the next position, discarding the worn edge and activating a fresh cutting edge, thereby extending the total usable life of the insert while maintaining reliability
3Length of moving object
If solid end mills are used for small diameters, then the single integrally formed body allows milling in smaller locations, but the entire tool must be replaced after wear and material usage is higher
Solution Approach 1:
The cutting tool is segmented into two separate components: a reusable tool holder and a replaceable insert. This segmentation allows the expensive tool holder to be used repeatedly while only the cheaper insert needs replacement after wear. The insert can be indexed through four positions before replacement, effectively reducing material consumption compared to replacing the entire solid end mill
Solution Approach 2:
The design enables recovery and reuse of the tool holder body while discarding only the worn insert. The insert can be indexed through four cutting edges before replacement, maximizing the utilization of the tool holder structure and minimizing material waste compared to replacing the entire solid end mill after a single life cycle
4Loss of substance
If insert-mills are used instead of solid end mills, then replaceable inserts reduce material cost, but the tool holder structure becomes more complex
Solution Approach 1:
The tool system is segmented into a tool holder and replaceable insert, allowing the expensive material to be concentrated only in the insert rather than the entire tool. This segmentation reduces overall material cost while the tool holder provides the necessary structural support and mounting mechanism
Solution Approach 2:
The tool holder is designed as a universal component that can accommodate multiple inserts through four indexable positions. This multi-functionality allows the same tool holder structure to support various cutting operations and extend the operational life of each insert, justifying the structural complexity through enhanced versatility and cost efficiency
Data Source
AI summary
A single-sided four-way indexable cutting insert includes a positive basic shape, a rake surface, a peripheral surface including four side abutment surfaces, a base bearing surface and a screw hole connecting the rake and base bearing surfaces. The insert has an imaginary square frustum which defines a square base containing the cutting insert's base bearing surface, and further defines four isosceles trapezoid side surfaces respectively containing the cutting insert's four side abutment surfaces. A material volume VF of the cutting insert and a void volume VS of the insert fulfill the condition VS/VF≥0.25.