Ceramic-Carbide Milling Cutter Structure for Deep Pocket Stability
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Solution Overview
Problem
Current milling tools face challenges in achieving high toughness and hardness simultaneously, especially when cutting deep pockets in heat-resistant super alloys, leading to issues like tool breakage and vibration during high-speed machining, while also being cost-effective and having predictable tool life.
Innovation Solution
A milling device with a ceramic front part and a cemented carbide rear part, bonded by a strong joint, which enhances bending resistance and reduces vibration, allowing for longer tool life and lower production costs by using less expensive materials and minimizing the risk of chatter marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a monolithic ceramic milling tool is used to achieve high hardness and heat resistance, then the tool can withstand high cutting speeds and temperatures, but the tool becomes more brittle and has lower toughness leading to increased risk of breakage
Solution Approach 1:
The milling tool is divided into two separate parts: a ceramic front part containing the cutting edges and a cemented carbide rear part forming the tool body. This segmentation allows each part to be made from material optimized for its specific function - ceramic for heat resistance at the cutting edge and cemented carbide for toughness and vibration resistance in the tool body.
Solution Approach 2:
The tool combines two different materials (ceramic and cemented carbide) into a single composite structure. The ceramic front part provides high hardness and heat resistance for cutting, while the cemented carbide rear part provides high toughness and damping capacity, creating a composite tool that exhibits properties superior to either material alone.
2Duration of action of moving object
If ceramic material is used for the entire milling tool to achieve high hardness, then the tool life at high cutting speed is improved, but the production cost increases due to the expensive ceramic material
Solution Approach 1:
The tool applies ceramic material only where it is most needed - at the front part containing the cutting edges that experience high temperatures and wear. The rear part of the tool, which does not require the same heat resistance, is made from less expensive cemented carbide. This local application of expensive material optimizes tool life where critical while minimizing overall production cost.
3Length of moving object
If a long and slender milling tool is used to cut deep pockets, then the tool can reach deep cavities in work pieces, but the tool is more prone to vibrations and chatter marks during high-speed machining
Solution Approach 1:
The cemented carbide rear part of the tool provides high damping capacity and mass, which effectively suppresses vibrations and chatter in long, slender tool configurations. This composite structure allows the tool to maintain stability during high-speed machining of deep pockets without compromising the heat resistance at the cutting edges.
4Device complexity
If the cutting edges are located close to the joint between ceramic and cemented carbide parts, then the tool structure is more compact, but the joint is exposed to high temperatures leading to potential failure
Solution Approach 1:
The tool design features an asymmetric distribution of the cutting edges relative to the joint, with the cutting edges positioned at a distance from the joint between the ceramic and cemented carbide parts. This asymmetric positioning ensures that the joint is not exposed to the extreme temperatures at the cutting zone, protecting the joint integrity while maintaining a compact overall structure.
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 milling device achieves improved tool life, reduced vibration, and lower production costs by leveraging the toughness of cemented carbide and the hardness of ceramic, while maintaining high precision and reducing material costs.
Implementation Method 1
The ceramic front part and the cemented carbide rear part are permanently bonded or brazed to each other by a joint
Implementation Method 2
The joint may also be glue, which can be used to achieve to permanent bond
Data Source
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AI summary
The invention relates to a milling device (1), rotatable in one direction around a longitudinal center axis (A) defining a forward direction and an opposite rearward direction, comprising a front part (3) and a rear part (2). The front part (3) comprising cutting edges (4, 4') each having a longitudinal extension, the front part (3) comprising chip flutes (5, 5') each having a longitudinal extension, the front part (3) is made of a monolithic piece of ceramic. The rear part (2) is configured to be fixed in a rotatable tool body or a rotatable chuck. The rear part (2) is made of a monolithic piece of cemented carbide. A front end surface of the rear part (2) having a smaller area than a rear end surface of the front part (3), the front end surface of the rear part (2) and a rear end surface of the front part (3) being permanently bonded or brazed to each other by a joint.