Laminate Molding Apparatus Displacement Correction
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Solution Overview
Problem
Laminate molding processes face challenges in achieving high accuracy due to residual stresses and displacements in metal laminate objects caused by thermal expansion and rapid cooling, leading to reduced size and shape accuracy of the final molded product.
Innovation Solution
A laminate molding apparatus that includes a laser emitting unit and a shape correction computation device to calculate and correct displacements by generating a corrected molding program based on three-dimensional shape data, ensuring accurate molding by forming sintered layers and facilitating martensitic transformation through heat treatment for carbon steel materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If uniform correction is applied to the molding program based on sintering contraction rate data, then displacement during molding is corrected, but size accuracy and shape accuracy of the obtained molded object are lowered due to additional residual stresses generated after molding
Solution Approach 1:
The patent divides the correction process into two distinct stages: (1) correction for displacement during molding based on sintering contraction rate data, and (2) correction for residual stress-induced displacement after molding based on measured actual displacement. This segmentation allows each correction to address specific sources of error independently, preventing the compounding of inaccuracies that occurs with uniform correction approaches.
Solution Approach 2:
The patent implements a feedback mechanism where the actual displacement of the molded object after molding is measured and used to generate additional correction data. This measured feedback is then applied to refine the molding program, creating a closed-loop system that continuously improves accuracy by learning from actual outcomes rather than relying solely on theoretical contraction rates.
2Ease of manufacture
If multiple sintered layers are laminated to form the molded object, then the desired laminate molded object is obtained, but residual stress is generated in the lamination direction in addition to stresses from thermal melting and rapid cooling
Solution Approach 1:
The patent applies preliminary correction to the molding program by calculating expected residual stress based on the number of sintered layers and their lamination direction. This correction is applied before molding begins, allowing the molding program to pre-compensate for the cumulative residual stress that will be generated during the lamination process, rather than attempting to correct for it after the fact.
Solution Approach 2:
The patent modifies molding parameters based on the number of sintered layers and lamination direction. By changing parameters such as laser power, scanning speed, or layer thickness in response to the specific lamination configuration, the system optimizes the molding process to minimize residual stress generation while maintaining the ability to form complex multi-layer structures.
3Productivity
If rapid cooling is performed after thermal melting to form sintered layers, then efficient molding is achieved, but tensile stress becomes residual stress in the molded object
Solution Approach 1:
The patent applies preliminary anti-action by calculating the expected tensile residual stress generated by rapid cooling and applying an opposing correction to the molding program. This pre-compensation approach counteracts the harmful tensile stress before it fully develops during the molding process, allowing rapid cooling to be maintained for efficiency while minimizing its adverse effects on final part accuracy.
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 enables high-accuracy molding by correcting displacements and residual stresses, improving working efficiency by shortening the time required for displacement completion and enhancing the precision of subsequent molded objects with the same shape.
Implementation Method 1
a laser emitting unit emits a laser beam to an emission area of a powder layer made of a metal material powder and formed on a predetermined molding part and form a sintered layer
Implementation Method 2
form a sintered layer based on a molding program corresponding to three-dimensional shape data of a molded object to be created
Implementation Method 3
facilitating martensitic transformation through heat treatment for carbon steel materials
Data Source
AI summary
A laminate molding apparatus calculates three-dimensional finished shape data after displacements occurred after molding of the initial molded object are completed based on a molding program corresponding to three-dimensional shape data of a molded object to be created, compares the three-dimensional finished shape data of the initial molded object with three-dimensional shape data to calculate a correction data of the displacement, creates a corrected molding program corresponding to corrected three-dimensional shape data in which coordinates of the surface of the molded object to be created by adding the correction data to the three-dimensional shape data, and molds a corrected molded object under the same molding conditions as when the initial molded object is molded based on the corrected molding program.