Composite Cemented Carbide Rotary Tools with Internal Cooling
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Solution Overview
Problem
Monolithic cemented carbide rotary tools experience uneven wear and short service life due to variations in cutting speeds from the center to the periphery, leading to frequent regrinding and downtime, and there is a need for tools with composite construction and coolant channels for improved performance and versatility.
Innovation Solution
A method of forming composite rotary tools by injecting two composite materials with differing cemented carbide grades and binder compositions into a mold, creating regions with varying properties and incorporating internal coolant channels, such as helical channels, to achieve uniform wear and enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If monolithic cemented carbide construction is used, then manufacturing simplicity is maintained, but uniform wear and service life are compromised due to cutting speed variations from center to periphery
Solution Approach 1:
The patent applies local quality by creating a composite tool construction with different cemented carbide grades in different regions. The first grade with higher cobalt content is placed in the center region where cutting speeds are lower, providing greater toughness. The second grade with lower cobalt content is placed in the outer region where cutting speeds are higher, providing greater wear resistance. This regional differentiation of material properties resolves the contradiction by matching local material characteristics to local operating conditions.
Solution Approach 2:
The patent employs composite materials by combining two different cemented carbide grades in a single tool construction. Each grade has distinct compositional characteristics (different cobalt percentages) that provide complementary properties. This composite approach allows the tool to simultaneously achieve the toughness needed for center regions and the wear resistance needed for outer regions, resolving the uniform wear problem while maintaining manufacturing feasibility through injection molding.
2Reliability
If composite construction with different cemented carbide grades is implemented, then uniform wear and service life are improved, but device complexity increases
Solution Approach 1:
The patent merges the manufacturing of multiple material zones and coolant channels into a single injection molding operation. By incorporating the mold cavity design that simultaneously forms both cemented carbide grade regions and internal coolant channels in one process step, the patent reduces overall device complexity despite using composite materials. The mold cavity geometry directly translates to the final tool structure, eliminating the need for separate manufacturing and assembly operations.
Solution Approach 2:
The patent applies preliminary action by pre-forming the complex composite structure and coolant channels during the injection molding process itself. The mold cavity is designed to create the multi-grade cemented carbide construction and internal channels in advance, before sintering. This preliminary formation of complex features during molding eliminates the need for subsequent complex machining or assembly operations, thereby reducing overall device complexity while achieving the desired composite construction.
3Reliability
If internal coolant channels are incorporated, then cooling efficiency and chip ejection are improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the formation of coolant channels with the formation of the cemented carbide tool body in a single injection molding process. The mold cavity includes features that directly form internal coolant channels within the tool structure during molding, before sintering. This integrated approach eliminates the need for separate drilling, machining, or assembly operations to create coolant passages, thereby reducing manufacturing complexity while achieving effective internal cooling and chip ejection capabilities.
4Reliability
If frequent regrinding is performed to address uneven wear, then tool functionality is maintained, but productivity decreases due to downtime
Solution Approach 1:
The patent applies local quality by matching different cemented carbide grades to different operational zones of the tool. The outer region experiences higher cutting speeds and greater wear, so it is made from a grade with lower cobalt content and higher wear resistance. The center region experiences lower cutting speeds and is made from a grade with higher cobalt content and greater toughness. This localized optimization ensures uniform wear across the entire cutting surface, eliminating the need for frequent regrinding and maintaining productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method allows for the creation of rotary tools with tailored properties and extended service life by ensuring uniform wear across the cutting surface and efficient cooling, reducing downtime and improving machining efficiency.
Implementation Method 1
The present invention is generally directed to methods of forming articles, such as tool blanks and other injection molded articles, having a composite construction
Implementation Method 2
The compact is then sintered to form a cylindrical tool blank having a solid monolithic construction
Implementation Method 3
The coolant may enter the channel at the shank end and exit at the drill point. The coolant cools the rotary tool and work piece
Data Source
AI summary
A method of forming a composite article by injecting at least two composite materials comprising metal carbides into a mold to form a green compact is disclosed. The composite materials may be metal powders comprising a binder metal, a hard particle. The composite material may further comprise a plastic binder. The two different composite materials are injected into the mold to form the green compact. Additionally, the composite materials may be injected through a die before entering the mold. In a specific embodiment, the die forms at least one internal channel within the green compact.