Blind Hole Shearing With Variable Punch Speed for Surface Integrity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for creating blind holes in metallic workpieces, especially those with curved surfaces, often result in suboptimal surface quality and structural integrity due to limitations in shearing processes.
Innovation Solution
A method combining high-speed and conventional shearing using a negative form with a recess and punch guide, where the punch moves at different velocities to achieve adiabatic shearing and subsequent compacting, ensuring a clean parting surface and spot welding for enhanced surface quality and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional shearing is used to create a blind hole, then the material can be displaced into the workpiece, but the surface quality and structural integrity are suboptimal
Solution Approach 1:
The shearing process is divided into two distinct stages: high-speed shearing for initial material separation and conventional shearing for final shaping and compaction. This segmentation allows each stage to optimize for its specific function, resulting in superior surface quality and structural integrity
Solution Approach 2:
The punch velocity is dynamically adjusted during the shearing process, transitioning from high speed in the first stage to lower speed in the second stage. This dynamic velocity change enables optimal material flow control and surface finish achievement
2Manufacturing precision
If high-speed shearing is used, then a clean parting surface is achieved, but the material may flow away causing destruction of the negative form
Solution Approach 1:
The negative form is preliminarily designed with a recess that anticipates the material displacement during high-speed shearing. This preliminary structural preparation prevents material flow away and potential destruction of the negative form
Solution Approach 2:
The punch velocity parameter is changed between two stages: high velocity in the first stage for clean parting surface creation, and reduced velocity in the second stage for controlled material compaction without excessive flow
3Manufacturing precision
If the punch velocity is reduced in the second movement section, then material flows into the recess for high surface quality, but the shearing process takes longer
Solution Approach 1:
The shearing process uses periodic action with two distinct velocity phases: a fast initial phase for material separation and a slower second phase for surface quality optimization. This periodic velocity variation balances productivity and precision
4Strength
If the punch compacts the material in the region of the recess, then structural integrity is enhanced through spot welding, but the punch experiences wear
Solution Approach 1:
The punch velocity parameter is reduced in the second movement section, allowing controlled material compaction and spot welding formation without excessive friction and wear on the punch
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 produces blind holes with exceptional surface quality and structural integrity by employing two-stage shearing with varying velocities, reducing wear on the punch and maintaining the blind hole bottom through compression and spot welding.
Implementation Method 1
the material encountered by the punch in the first movement section B1 is sheared in an adiabatic state (high-speed shearing)
Implementation Method 2
the material encountered by the punch in the second movement section B2 is sheared and compacted on an annular step formed by the different diameters of the recess (inner diameter) and the punch (outer diameter)
Implementation Method 3
Thanks to the shearing, furthermore, a spot welding can occur in the structure, so that the blind hole has an especially advantageous configuration due to its fabrication
Data Source
AI summary
A method for making a blind hole may include arranging a workpiece in a negative form with a first portion and a second portion. The first portion may include a recess. The second portion may include a guide for a punch. The recess may be arranged substantially coaxially to the guide. The method may also include displacing a material of the workpiece into the recess via pressing the punch into the workpiece. Additionally, the method may include pressing the punch into the workpiece in a first movement section with a first velocity. The method may further include further pressing the punch into the workpiece in a second movement section with a second velocity such that the material is sheared and is partly extruded into the recess. The method may include moving the first portion relative to the second portion and shearing off the material displaced within the recess.