Interlace Scanning Strategies for Additive Manufacturing Heat Management
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Solution Overview
Problem
In additive manufacturing, controlling energy density and metallurgy across large-scale components is challenging, especially when forming scan regions that border each other, which can lead to excessive heat buildup and material defects like warping and porosity.
Innovation Solution
The method involves forming partially solidified portions in offset scan regions with interlocking solidification lines, where the irradiation paths intersect at a reference line parallel to the scan region boundaries, allowing for controlled energy distribution and improved metallurgical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional scanning strategies are used to form large-scale components with multiple scan regions, then build area coverage is improved, but excessive heat buildup occurs at the borders between scan regions leading to material defects
Solution Approach 1:
The build area is divided into multiple scan regions that are selectively irradiated in a sequential manner rather than all at once. This segmentation allows heat to dissipate between irradiation cycles in certain regions, preventing excessive heat buildup at scan region borders while still achieving complete coverage of the large-scale component.
Solution Approach 2:
The irradiation process employs periodic action by alternating between different scan regions across multiple build cycles. Regions that were irradiated in previous cycles are allowed to cool down before being irradiated again, creating a periodic pattern of heating and cooling that prevents thermal accumulation and associated material defects.
2Productivity
If high energy density is applied to melt powder rapidly, then build speed is improved, but thermal stress and localized non-equilibrium phases increase causing warping and porosity
Solution Approach 1:
The laser irradiation is applied in periodic cycles across different scan regions rather than continuously across the entire build area. This periodic application allows previously irradiated regions to cool and stabilize, reducing thermal stress and preventing warping and porosity while maintaining overall build speed through efficient cycle management.
Solution Approach 2:
Different scan regions receive irradiation at different times, creating local variations in thermal history. This local quality approach ensures that no single region experiences excessive cumulative heating, thereby preventing localized non-equilibrium phases and dimensional inaccuracies while maintaining high energy density where needed.
3Area of stationary object
If the laser scans across the entire build area in each cycle, then coverage is improved, but heat buildup at scan region borders increases causing material defects
Solution Approach 1:
The build area is segmented into multiple scan regions that are irradiated in alternating sequences across different build cycles. This segmentation strategy ensures that border regions between scan areas are not subjected to continuous irradiation from multiple adjacent regions, thereby reducing heat buildup at these critical interfaces while maintaining complete area coverage.
Solution Approach 2:
The scanning pattern implements periodic action by returning to previously irradiated scan regions only after other regions have been processed. This periodic revisiting allows thermal dissipation at scan region borders between cycles, preventing excessive heat accumulation and associated material defects while ensuring comprehensive coverage over time.
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 enhances the metallurgical properties and dimensional accuracy of the completed component by managing heat buildup and energy density across the build area, reducing defects and improving build efficiency.
Implementation Method 1
a laser beam to sinter or melt a fine powder
Implementation Method 2
The physical processes associated with laser sintering or laser melting include heat transfer to a powder material
Implementation Method 3
melting layers of powder successively to build an object in a metal powder
Implementation Method 4
sintering entails fusing (agglomerating) particles of a powder at a temperature below the melting point of the powder material
Data Source
AI summary
A method, apparatus, and program for additive manufacturing. In one aspect, the method comprises: forming an at least partially solidified portion within a first scan region (801), wherein the solidified portion within the first scan region (801) is formed by irradiating a build material along a first irradiation path (811). A second portion of a build material may be irradiated along a second irradiation path (813), wherein the second scan region (803) is offset with respect to the first scan region (801) thereby defining an offset region (802). The offset region (802) is at least partially solidified by the first irradiation path (811) and the second irradiation path (813) and a reference line (819) intersects the first irradiation path (811) and the second irradiation path (813) within the offset region (802), wherein the reference line (819) is substantially parallel to a side (810) of the first scan region (801).