Contour-Based Hatch Layout for Crack-Resistant Metal AM
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Solution Overview
Problem
Additive manufacturing (AM) processes, particularly direct metal laser melting (DMLM), face challenges in minimizing microcrack formation in fabricated parts due to conventional fixed-angle laser hatch lines that do not account for the geometry of the part, leading to reduced quality, especially in thin or narrow regions.
Innovation Solution
The method involves generating contour-based hatching patterns where laser hatch lines are oriented normal to the part's contours, with each layer's hatch pattern determined by its inner and outer contours, and incorporating techniques like spline smoothing and inter-layer hatch angle rotation to minimize crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fixed-angle laser hatch lines are used, then the manufacturing process is simple, but the quality of the fabricated part deteriorates due to microcrack formation
Solution Approach 1:
The hatching pattern dynamically adapts to the local geometry of the part by calculating the contour angle at each point and orienting the hatch lines perpendicular to the contour. This transforms the static fixed-angle approach into a dynamic geometry-aware process that automatically adjusts hatch orientation based on the part's shape, thereby preventing microcracks in thin or narrow regions while maintaining process simplicity through automated calculation.
Solution Approach 2:
The hatching process applies different hatch orientations to different regions of the part based on local geometry characteristics. By evaluating the contour angle at each point and setting the hatch angle perpendicular to the local contour, the system ensures that each region receives optimized hatching tailored to its specific shape, preventing microcracks in critical areas while maintaining overall part quality.
2Reliability
If fixed-angle laser hatching is used, then the process is easy to implement, but the reliability of the part deteriorates due to crack formation in thin regions
Solution Approach 1:
The system implements a dynamic hatching algorithm that calculates the contour angle at each point along the part geometry and automatically determines the optimal hatch orientation perpendicular to the local contour. This dynamic adaptation ensures that hatch lines are always oriented to minimize stress concentration and prevent microcrack formation, thereby improving part reliability while the automated calculation keeps the implementation manageable.
Solution Approach 2:
The patent replaces the simple mechanical approach of fixed-angle hatching with a computational geometry-based system that automatically calculates optimal hatch orientations. By substituting the mechanical fixed-angle method with an algorithmic contour-analysis system, the patent achieves improved reliability through geometry-aware hatching while managing complexity through automated computation rather than manual intervention.
3Manufacturing precision
If laser hatch lines are oriented at fixed angles, then the manufacturing process is straightforward, but the manufacturing precision deteriorates due to improper hatch alignment with part geometry
Solution Approach 1:
The hatching system dynamically adjusts the hatch angle at each point based on the local contour angle of the part. By continuously calculating the contour angle and setting the hatch angle perpendicular to it, the system achieves precise hatch alignment with the part geometry throughout, ensuring optimal manufacturing precision while the automated calculation process manages the complexity of determining appropriate hatch orientations.
Solution Approach 2:
The patent applies local quality optimization by determining the contour angle at each specific point along the part geometry and orienting the hatch lines perpendicular to the local contour at that point. This point-by-point optimization ensures that each region receives hatching precisely aligned with its local geometry, maximizing manufacturing precision while the systematic approach to local determination keeps the overall process manageable.
Data Source
AI summary
A system and method including receiving a data model representation of a part, the data model representation including at least one layer of the part and inner and outer contours for the at least one layer; determining a hatch pattern for each layer of the at least one layer of the part, the hatch pattern for each layer being dependent on the inner and outer contours for each respective layer; generating a record of the determined hatch pattern for each layer, the record including locations for the hatch pattern for each layer; and saving the record of the determined hatch pattern for each layer of the part. In some aspects, the record of the determined hatch pattern for each layer of the part may be used in an additive manufacturing process.