Laser Sintering Method for Thin Walls with Localized Solidification
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Solution Overview
Problem
Existing methods for manufacturing objects with thin walls and complex shapes using laser sintering face challenges such as residual stresses, deformations, and unwanted solidification in undercut areas, leading to structural defects like burrs and weakened walls due to differences in thermal conductivity between powder and solidified material.
Innovation Solution
The method involves creating a second solidified area with lower mechanical resistance around the object's constituent parts, using reduced thermal energy or higher scanning speed to minimize thermal conductivity differences, and optionally employing multiple lasers or different powders to produce areas that support the main walls without inducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser is used to rapidly solidify powder areas to form thin walls, then the manufacturing capability for thin walls and complex shapes is improved, but residual stresses and local deformations occur due to significant local temperature rise
Solution Approach 1:
The patent applies different thermal treatments to different areas: the first area receives high-energy laser treatment for complete solidification to form the thin wall, while the second area receives lower-energy treatment for partial solidification. This creates local quality differences where the first area has high mechanical resistance and the second area has lower mechanical resistance, resolving the contradiction by localizing the high precision treatment only where needed.
Solution Approach 2:
The patent segments the solidification process into two distinct areas with different solidification conditions. The first area is completely solidified with high mechanical resistance, while the second area is partially solidified with lower mechanical resistance. This segmentation allows the thin wall to be formed with high precision while the surrounding area provides stress relief, preventing residual stresses and deformations.
2Manufacturing precision
If laser beam works on powder to sinter the area forming the wall, then the wall is solidified, but temperature rise in adjacent undercut areas causes unplanned solidification and deformations
Solution Approach 1:
The patent creates a localized thermal field where the first area (wall region) receives high-energy laser treatment for complete solidification, while the second area (undercut region) receives lower-energy treatment for partial solidification. This local quality differentiation prevents harmful unplanned solidification in undercut areas by controlling the thermal energy distribution spatially.
Solution Approach 2:
The patent converts the harmful effect of thermal radiation to undercut areas into a beneficial partial solidification. By intentionally allowing partial solidification in the second area with lower mechanical resistance, the patent prevents complete unplanned solidification that would cause deformations, while still utilizing the thermal energy to provide support structure.
3Strength
If powder areas are completely solidified to form strong walls, then mechanical resistance is improved, but thermal conductivity differences between powder and solidified material cause deformations
Solution Approach 1:
The patent creates local quality differences in solidification: the first area is completely solidified with high mechanical resistance matching the solidified material's thermal conductivity, while the second area is partially solidified with lower mechanical resistance. This localized approach allows strong walls where needed while managing thermal conductivity transitions to prevent deformations.
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
This approach prevents deformations and structural defects by ensuring the second solidified areas are sufficiently strong to support the main walls, maintaining controlled thermal conductivity and allowing for the production of objects with thin walls and complex shapes without defects.
Implementation Method 1
a laser to supply, locally and rapidly, the energy required to solidify the area intended to form the wall of the object
Implementation Method 2
solidifying by melting under the effect of the thermal energy provided by a laser
Implementation Method 3
a temperature rise, due to radiation, of the powder in the area adjacent to that undergoing sintering occurs
Data Source
AI summary
This process for manufacturing an object by solidifying a powder (P) includes steps of: a) depositing a powder layer (P) on a working zone (Z); b) compacting this layer; c) solidifying a first zone (7) of the compacted layer using a laser; d) solidifying at least one second zone (11, 12, 13) of the compact layer, this second zone (11, 12, 13) making contact with the zone (7) solidified in step c), under solidifying conditions chosen so that this second solidified zone (11, 12, 13) is less strong than the first solidified zone (7); e) repeating steps a) to d) until the object (1) is obtained; and f), after step e) and when the object (1) is finished, removing the second zones (11, 12) with respect to the first zones (7).