Additive Manufacturing Multi-Spot Beam Control for Narrow-Area Precision
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Solution Overview
Problem
Existing three-dimensional modeling apparatuses face issues with dimensional accuracy due to unintended fusion of modeling material in narrow non-writing areas, caused by thermal diffusion and light quantity variations at the boundaries of writing areas, leading to degradation of the modeled object's precision.
Innovation Solution
A three-dimensional modeling apparatus that includes a control system to suppress light emission onto narrow non-writing areas and adjust light intensity in adjacent areas, using a multi-spot beam with controlled light patterns based on design data to prevent unintended fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser beam is scanned on resin powder to fuse and solidify the modeling material for three-dimensional modeling, then the modeled object is formed through layer-by-layer solidification, but unintended fusion occurs in narrow non-writing areas due to thermal diffusion and light quantity variations at boundaries, degrading dimensional accuracy
Solution Approach 1:
The patent applies local quality by differentiating the treatment of writing areas and non-writing areas. The control unit selectively modulates the laser beam to emit light only in writing areas while suppressing light emission in non-writing areas, including narrow non-writing areas. This localized control prevents unintended fusion in specific regions while maintaining necessary fusion in designated areas, thereby resolving the contradiction between achieving complete fusion where needed and preventing unwanted fusion where not needed.
Solution Approach 2:
The patent implements preliminary anti-action by proactively suppressing light emission in non-writing areas before unintended fusion can occur. The control unit identifies narrow non-writing areas based on size criteria and pre-emptively prevents laser exposure in these regions, counteracting the potential harmful thermal diffusion and light quantity variations at boundaries before they can cause unwanted fusion.
2Productivity
If resin powder is heated to a predetermined preheating temperature lower than melting point by several °C to ten several °C and laser beam is emitted, then the laser beam effectively fuses the resin powder, but the temperature in areas around the writing area increases due to thermal diffusion, causing fusion contrary to intention in narrow non-writing areas
Solution Approach 1:
The patent applies local quality by implementing spatially selective laser emission. The control unit modulates the laser beam based on position, allowing effective fusion in writing areas while suppressing emission in non-writing areas. This localized control enables the preheating temperature to be maintained without causing unwanted fusion, as the laser energy is selectively applied only where intended, preventing thermal diffusion from causing dimensional inaccuracies.
Solution Approach 2:
The control unit acts as an intermediary between the laser beam and the resin powder. It selectively modulates the laser beam to allow passage of light in writing areas while blocking or suppressing light in non-writing areas. This intermediary control mechanism enables effective fusion where needed while preventing unwanted fusion caused by thermal diffusion, thus maintaining both productivity and dimensional accuracy.
3Manufacturing precision
If new resin powder is supplied onto the already-written layer and laser beam is emitted immediately above the writing area, then the pattern is written on the new layer, but the temperature above the writing area and surrounding area in the already-written layer becomes higher than preheating temperature, causing fusion contrary to intention
Solution Approach 1:
The patent applies local quality by implementing layer-specific and area-specific laser control. When writing on a new layer, the control unit suppresses laser emission not only in non-writing areas of the current layer but also in corresponding areas of the underlying layer where temperature is already elevated. This localized control prevents contrary intention fusion in the underlying layer while maintaining pattern accuracy in the current layer being written.
Solution Approach 2:
The patent implements preliminary action by anticipating and preventing contrary intention fusion before it occurs. The control unit identifies areas in the already-written layer that are at elevated temperature and pre-emptively suppresses laser emission in these regions during writing of the new layer. This preliminary prevention avoids the need for corrective actions and ensures pattern accuracy without causing unwanted fusion in underlying areas.
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 apparatus achieves high accuracy in forming modeled objects by preventing unintended fusion in narrow non-writing areas, maintaining precise dimensions and improving the overall quality of the modeled structure.
Implementation Method 1
the resin powder on the construction platform is heated to a predetermined preheating temperature lower than a melting point of the resin powder by several °C to ten several °C
Implementation Method 2
a laser beam is scanned on a layer of the resin powder by a galvano mirror or the like, to thereby fuse the resin powder in an irradiation area of the laser beam
Implementation Method 3
a temperature of the irradiation area of the laser beam (i.e., writing area) increases and thermal diffusion is caused toward a non-writing area around the writing area
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
In a three-dimensional modeling apparatus (1), a control part (5) controls a material holding part (3) and an optical head (2) on the basis of design data of a modeled object to supply a modeling material (91) onto a stage (341) and scan a multi spot beam in a predetermined scan direction on a writing target layer (92) which is a surface layer of the supplied modeling material (91), to thereby repeat fusing the modeling material (91) in an area on which light is emitted and writing of a pattern. A non-writing area on which writing is not instructed by the above-described design data includes a narrow non-writing area whose size in the scan direction is not larger than a correction threshold value. Then, with a control by the control part, emission of light onto a narrow-portion adjacent area adjacent to the narrow non-writing area in a writing area on which writing is instructed by the design data is suppressed. It is thereby possible to form a modeled object with high accuracy.