Intaglio Plate Laser Engraving Depth Profile Correction
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Solution Overview
Problem
Deep laser engraving of intaglio printing plates often results in deviations from specified depth profiles due to factors like non-flat material, dust, and material residues, leading to reduced power transfer and altered geometry, causing flatness issues and incomplete trapezoidal cross-section engravings.
Innovation Solution
Adapting the control engraving layers using a correction offset, which adjusts the areas to be engraved based on the target depth profile, effectively correcting for disruptive effects without requiring changes to the laser engraving device or complex post-processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If direct laser engraving is performed on intaglio printing plates, then complex three-dimensional depth profiles can be created, but the engraved depth profile deviates from specifications due to energy loss and material residue
Solution Approach 1:
The method performs preliminary cleaning of material residues and dust from the engraving area before each laser engraving pass. This preliminary action removes obstacles that would otherwise absorb or scatter laser energy, ensuring consistent power transfer to the material throughout the engraving process and maintaining depth profile accuracy.
Solution Approach 2:
The system monitors the engraving process and adjusts laser parameters based on feedback from previous passes. By analyzing the actual material removal results and environmental conditions, the system dynamically modifies energy delivery to compensate for variations caused by material residues, ensuring consistent depth profile reproduction.
2Productivity
If laser energy is increased to compensate for power loss at depth, then material removal efficiency improves, but device complexity increases due to modifications required
Solution Approach 1:
The method changes operational parameters (laser power, pulse duration, scan speed) dynamically during the engraving process based on depth and material condition. This allows optimization of material removal efficiency at different stages without requiring permanent hardware modifications, maintaining productivity while avoiding increased device complexity.
Solution Approach 2:
The system employs dynamic adjustment of laser parameters during engraving rather than static settings. Laser power, pulse frequency, and scan speed are continuously adapted to match the actual engraving conditions, enabling efficient material removal throughout the depth profile without fixed device modifications.
3Manufacturing precision
If extensive post-processing is performed to correct engraving deviations, then depth profile accuracy improves, but loss of time increases
Solution Approach 1:
The method converts the potentially harmful effect of material residues into a beneficial process feature by systematically removing them during engraving. This integrated approach eliminates the need for separate post-processing steps, achieving high depth profile accuracy while minimizing total production time.
Solution Approach 2:
The cleaning function is merged with the engraving process itself. Material residue removal is performed in-situ during each engraving pass rather than as a separate post-processing operation, combining two functions into one continuous process that saves time while maintaining precision.
4Manufacturing precision
If the laser beam is focused to increase power density, then material removal precision improves, but the focusing effect reduces power availability at edges
Solution Approach 1:
The system applies different laser parameters to different regions of the workpiece. Central areas receive higher power density for precise material removal, while edge areas receive adjusted parameters to ensure adequate power availability. This local optimization maintains precision where needed while preserving overall material removal efficiency.
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
Significantly improves the quality of laser engraving with minimal effort, reducing deviations between target and actual depth profiles, allowing for high-quality security features on security documents like banknotes and stamps.
Implementation Method 1
The surface of the blank for the intaglio printing plate is scanned in several layers using the laser to remove material layer by layer
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A method for engraving an intaglio printing plate (1) with a laser is proposed, wherein a depth profile (2) of the intaglio printing plate (1) is generated by engraving several engraving layers (3) using the laser, wherein a target engraving layer (5) is determined for each of the engraving layers (3) based on a predetermined target depth profile (4), wherein flank angles are determined for the edges (6) of the areas (7) to be engraved of the target engraving layers (5), wherein a correction offset (8) is determined for each target engraving layer (5) and each flank angle in this target engraving layer (5), wherein the areas (7) to be engraved of each target engraving layer (5) are adapted at the edges (6) by means of the respective correction offset (8) for the creation of control engraving layers (9), wherein the control engraving layers (9) are used to control the laser during the engraving of the Engraving layers (3) are used.