Adjustable Punch Assembly Shim Block for Precision Hole Alignment
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Solution Overview
Problem
Existing punch assemblies in high-speed automated punch presses face issues with punch point dullness leading to increased scrap rates and costly replacements, as well as inaccurate hole placement due to the use of urethane strippers which wear quickly and fail to maintain workpiece alignment.
Innovation Solution
A punch assembly design featuring a centrally located shank with a circular alignment ring, a steel stripper plate, and compression springs, along with a shim block and punch point member that can be adjusted using shim stock or threaded connections to accommodate metal loss during sharpening, ensuring accurate alignment and extended punch point life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If repeated sharpening is performed on the punch point, then the punch point can be reused longer, but metal is removed so it can no longer punch through the workpiece and only serves to distort the workpiece, resulting in increased scrap rate
Solution Approach 1:
The punch point member is made adjustable through a threaded connection between the shank and alignment ring, allowing the punch point position to be dynamically adjusted downward as metal is removed during sharpening. This dynamic adjustment capability enables the punch point to maintain proper engagement with the workpiece throughout its service life, resolving the contradiction between extended usage and maintained precision.
2Adaptability or versatility
If urethane strippers are used to allow punching close to non-flat workpiece surfaces, then flexibility is improved, but they are incapable of accurately holding the workpiece during punching, resulting in misalignment of the punched hole
Solution Approach 1:
The stripper material is changed from urethane to metal, fundamentally altering the physical parameters of the stripper including its rigidity, durability, and guiding capability. This material parameter change enables the stripper plate to provide both the adaptability to accommodate non-flat surfaces and the precision required for accurate hole alignment, resolving the contradiction between flexibility and precision.
3Ease of manufacture
If urethane strippers are used, then installation is simplified, but they are subject to rapid wear, requiring frequent replacement
Solution Approach 1:
The stripper plate is constructed from metal material, creating a composite structure when combined with the punch assembly components. This material substitution dramatically extends the stripper's service life while maintaining ease of installation through the same coupling mechanism, resolving the contradiction between installation simplicity and component durability.
4Duration of action of moving object
If the punch point member is made adjustable to accommodate metal loss, then punch point life is extended, but device complexity increases due to additional adjustment mechanisms
Solution Approach 1:
The adjustment mechanism is merged with the existing threaded connection structure between the shank and alignment ring. The punch point member utilizes this pre-existing threading for both structural attachment and adjustment functionality, eliminating the need for separate adjustment components. This merging approach extends punch point life while minimizing increases in device complexity.
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 solution significantly extends the life of the punch point by allowing for adjustments to compensate for metal loss and provides accurate hole placement through improved workpiece alignment, reducing scrap rates and operational costs.
Implementation Method 1
Disposed between the alignment ring and the stripper plate are a plurality of compression springs that normally urge the stripper plate away from the alignment ring
Data Source
AI summary
A punch assembly for a hydraulic punch press machine that affords the ability to compensate for punch point metal loss due to resharpening by facilitating accurate repositioning of the punch point relative to an aperture in a stripper plate through which the punch point member projects during a stamping stroke of the punch assembly.