ECAP Workpiece Machining with Radial Hammering
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Solution Overview
Problem
Existing methods for machining metallic workpieces using ECAP are limited by the length of workpieces that can be processed due to the limited stroke of the punch, and post-processing techniques like rolling often reduce mechanical properties or increase brittleness.
Innovation Solution
A method involving ECAP followed by hammering, where tools exert radial forming strokes on a rotating workpiece to achieve a permanent diameter reduction, significantly improving tensile strength and hardness while maintaining ductility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ECAP is used to machine workpieces, then mechanical strength and hardness are improved, but the length of workpieces that can be processed is limited due to punch stroke constraints
Solution Approach 1:
The invention transforms the static punch-pressing process into a dynamic continuous process by rotating the workpiece against stationary tools. The workpiece rotates around its longitudinal axis while tools exert radial forming strokes, enabling continuous processing of long workpieces beyond the original punch stroke limitation.
Solution Approach 2:
The invention adds rotational motion around the longitudinal axis to the traditional linear pressing process. This dimensional change from one-dimensional linear motion to two-dimensional rotational motion enables continuous processing and overcomes the stroke length constraint.
2Shape
If post-processing techniques like rolling are used after ECAP, then diameter reduction is achieved, but mechanical properties are reduced and brittleness increases
Solution Approach 1:
Instead of using conventional rolling that compresses the workpiece between two rollers, the invention inverts the approach by having stationary tools exert radial forming strokes on a rotating workpiece. This reversal of the processing sequence and mechanism achieves diameter reduction while preserving mechanical properties.
Solution Approach 2:
The invention employs periodic radial forming strokes applied to the rotating workpiece. The tools deliver intermittent impact loads in the radial direction during rotation, which differs from the continuous compressive loading of conventional rolling and avoids excessive brittleness.
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
This approach allows for the production of workpieces with enhanced mechanical properties, enabling longer workpieces to be processed and improving their strength and hardness without compromising ductility, making them suitable for medical implants and other applications.
Implementation Method 1
a metal workpiece is subjected to very large plastic deformation to produce an ultrafine microstructure (UFG 'ultra fine grained')
Implementation Method 2
a (permanent) diameter reduction (due to plastic deformation of the workpiece material) is achieved
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a method for machining a workpiece from a metallic material, in which the workpiece is machined by means of ECAP, characterized in that the workpiece, after the machining by means of ECAP, is post-processed by means of hammering, whereby a diameter reduction is achieved. As a result, material properties of the material of the workpiece and in particular the strength and the hardness can be considerably enhanced.