Long Cutting Knife Structure for Preventing Edge Plastic Deformation
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Solution Overview
Problem
Conventional long cutting knives experience plastic deformation due to heavy loads during the cutting process, especially when encountering curved or bent portions of wood, and using high-strength steel materials to prevent this deformation is costly.
Innovation Solution
A long cutting knife design featuring a blade metal with a cutting edge and a base metal joined to it, where the base metal is made of quenched steel with a yield point of 305 N/mm² or more, allowing for elastic deformation to absorb heavy loads and prevent plastic deformation of the cutting edge, while using less expensive materials like carbon steel or alloy steel for machine structural use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-strength alloy tool steel or high-speed tool steel is used for the entire cutting knife, then plastic deformation of the cutting edge is prevented, but manufacturing cost increases significantly
Solution Approach 1:
The cutting knife is divided into two distinct parts: a blade metal portion containing the cutting edge and a base metal portion providing structural support. This segmentation allows each part to be made from materials optimized for its specific function, with the blade metal using expensive high-strength steel only where needed at the cutting edge, while the base metal uses more economical materials.
Solution Approach 2:
Different material properties are assigned to different regions of the cutting knife. The blade metal portion requires high strength and wear resistance for cutting, while the base metal portion requires sufficient strength to prevent plastic deformation under heavy loads but can use more cost-effective materials. This local differentiation of material quality resolves the contradiction between performance and cost.
2Ease of manufacture
If the base metal uses inexpensive soft steel, then manufacturing cost is reduced, but the cutting edge becomes susceptible to plastic deformation under heavy loads
Solution Approach 1:
The cutting knife uses a composite structure combining blade metal and base metal with different mechanical properties. The blade metal provides cutting functionality while the base metal, though made from more economical materials, is designed with sufficient strength to prevent plastic deformation of the entire knife structure under heavy loads during rounding operations.
3Productivity
If the cutting edge cuts curved or bent portions of wood at high feed rate, then productivity is improved, but the cutting edge is subjected to heavy load causing plastic deformation
Solution Approach 1:
The base metal is designed and manufactured with predetermined strength characteristics before the cutting operation begins. This preliminary preparation ensures that when high feed rate cutting of curved wood portions occurs, the base metal is already positioned to absorb heavy loads and prevent plastic deformation of the cutting edge, allowing high productivity without compromising reliability.
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 design effectively prevents plastic deformation of the cutting edge by allowing the base metal to elastically deform, maintaining knife performance and reducing production costs.
Implementation Method 1
the base metal is a quenched steel material, and the yield point of the steel material before quenching is 305 N/mm 2 or more. Therefore, the steel material constituting the base metal has a wide stress range for elastic deformation. Consequently, the base metal may elastically deform even when heavy load is applied to the cutting edge during cutting.
Data Source
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AI summary
A long cutting knife (1) is used to cut wood (W) along an outer surface (W1) of the wood (W) to obtain a veneer. The long cutting knife (1) includes a blade metal (3) having a cutting edge (3a) at a tip end and a flank face (3c) on a rear face (3d). The long cutting knife (1) further includes a base metal (2) to which the rear face (3d) of the blade metal (3) is joined. The base metal (2) is a quenched steel material, and the yield point of the steel material before quenching is 305 N/mm2 or more.