Recessed Laser-Marked Metal Identifiers for Shot Blast Readability
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Solution Overview
Problem
Metal castings are prone to identification errors due to manipulation between the die-casting and identification stations, leading to potential misidentification and compromised tracking accuracy, especially when shot blasting can damage or erase existing identifiers.
Innovation Solution
Laser-marking shot-blast resistant identifiers on metal workpieces by creating recesses with specific dimensions in dark cells, ensuring the identifiers remain readable after shot blasting through a method that involves laser-removing metal from the surface only at the center portion of dark cells, leaving a recess bounded by a peripheral wall, which provides resistance to shot blasting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If identifiers are marked on metal castings before shot blasting, then identification can occur early in the production line, but the identifiers may be damaged or erased by shot blasting
Solution Approach 1:
The patent applies local quality by creating recesses with specific dimensional characteristics (depth, width, shape) only in the dark cells of the identifier, while leaving bright cells unaffected. This localized structural modification ensures that the dark cells maintain their optical properties after shot blasting, resolving the contradiction between early identification and identifier durability.
Solution Approach 2:
The patent implements preliminary action by laser-marking the identifier with recessed dark cells before the shot blasting process. The recesses are pre-formed to a specific depth and configuration that protects them from being eroded by shot blasting, allowing identification to occur early while ensuring the identifier survives the subsequent shot blasting operation.
2Measurement precision
If laser-marking removes metal from the entire dark cell area, then the identifier appears dark and readable, but shot blasting can erode the surface and compromise readability
Solution Approach 1:
The patent applies local quality by creating recesses with specific dimensional characteristics (depth, width, shape) only in the dark cells of the identifier, while leaving bright cells unaffected. This localized structural modification ensures that the dark cells maintain their optical properties after shot blasting, resolving the contradiction between early identification and identifier durability.
Solution Approach 2:
The patent implements beforehand cushioning by pre-forming recesses in the dark cells that act as a protective buffer against shot blasting erosion. The recess depth and configuration are specifically designed to absorb the impact of shot blasting particles, protecting the underlying dark cell structure from being completely eroded and maintaining identifier readability.
3Reliability
If recess depth is increased to improve shot blast resistance, then identifier durability improves, but manufacturing complexity and time increase
Solution Approach 1:
The patent applies parameter changes by optimizing the recess dimensions (depth, width, shape) to specific ranges that provide adequate shot blast resistance while maintaining manufacturing efficiency. The recess depth is set to a specific range (e.g., 10-50 micrometers) that balances protection against erosion with reasonable laser-marking time and process 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 allows for early and accurate identification of metal castings along the production line, maintaining identifier readability even after shot blasting, thereby reducing errors and ensuring traceability.
Implementation Method 1
laser-removing, for each one of the plurality of dark cells, metal from the surface of the metal workpiece only at a center portion of the corresponding dark cell
Data Source
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AI summary
There is described a metal workpiece generally having a surface and an identifier marked on said surface. The identifier has cells each having a corresponding cell size, including bright cells corresponding to a first binary value and dark cells corresponding to a second binary value different from the first binary value. The dark cells include a center portion being recessed relative to the surface thereby leaving a recess bounded by a peripheral wall in the corresponding dark cell, the recess having a depth of at least 100 microns and having an opening with a width ranging between 400 microns and 1750 microns and representing between 30 percent and 99 percent of the corresponding cell size such that the corresponding dark cell appears dark to an optical reader. The depth, the width and the cell size of the dark cells provide a shot blast resistance to the laser-marked identifier.