Cutting Surface Shot Peening and Grinding for Longer Knife Life
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Solution Overview
Problem
Existing methods for treating rotary knives and cutting pieces, such as ultrasonic cold forging technology, only double the number of coils that can be cut, which is not sufficient to extend their lifetime significantly.
Innovation Solution
A two-step method involving ultrasonic shot peening to create shot impacts on the cutting surface, followed by grinding to a chosen thickness, which increases the hardness and extends the lifetime of cutting pieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If ultrasonic cold forging technology is used to treat cutting pieces, then the number of coils that can be cut is doubled, but the lifetime extension is still not sufficient
Solution Approach 1:
The patent changes the treatment parameters by using ultrasonic shot peening instead of ultrasonic cold forging, applying shots with specific diameter (0.5-5mm) and weight (0.1-500g) to create controlled impacts that modify surface hardness and microstructure, achieving significantly extended lifetime
Solution Approach 2:
The patent applies preliminary ultrasonic shot peening treatment to the cutting surface before grinding, creating shot impacts that pre-harden the surface and induce beneficial residual stresses, which are then optimized by subsequent grinding to achieve the final required surface finish and hardness
2Strength
If the cutting surface is subjected to ultrasonic shot peening to create shot impacts, then the hardness is increased, but the surface roughness increases
Solution Approach 1:
The patent segments the treatment process into two distinct steps: first ultrasonic shot peening to increase hardness, then separate grinding to restore surface finish. This segmentation allows each process to optimize for its specific function without compromising the other
Solution Approach 2:
The patent extracts the surface layer affected by shot peening through controlled grinding, removing the roughened surface while preserving the hardened subsurface layer, thereby separating the hardening function from the surface finish requirement
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 significantly increases the hardness and lifetime of cutting pieces, allowing for the cutting of over 12270 tons of metal strip, equivalent to 380 km, compared to 75 km with traditional methods, thereby multiplying the length of metal strip that can be cut without defects.
Implementation Method 1
a first step in which a cutting surface of this cutting piece is subjected to shots thrown by an ultrasonic shot peening apparatus to become a cutting surface with shot impacts
Implementation Method 2
uses ultrasonic vibratory energy as a source and by which several tens of thousands of strikes per second are applied to the material surface at constant pressure
Implementation Method 3
a second step in which said cutting surface with shot impacts is grinded over a chosen thickness to become a treated cutting surface
Data Source
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AI summary
The invention relates to a method of treatment of a cutting piece (2). This method comprises a first step in which a cutting surface (5) of this cutting piece (2) is subjected to shots thrown by an ultrasonic shot peening apparatus (10) to become a cutting surface (5) with shot impacts, and a second step in which the cutting surface (5) with shot impacts is grinded over a chosen thickness to become a treated cutting surface (5).