Selective Melting Support Angles for Powder Bed Fusion
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Solution Overview
Problem
The existing sintering methods for manufacturing molding elements face challenges in achieving stable support during the layer-by-layer construction, particularly for certain shapes, leading to inefficiencies and increased costs due to the need for extensive secondary elements that are later scrapped.
Innovation Solution
The method involves determining specific angles between the main element's surface portions and the support plate to optimize the use of secondary elements, allowing partial support of the main element, which reduces the need for extensive secondary elements and conserves unmelted powder for reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If joining parts with smaller thickness are used to support the molding element, then the molding element can be detached more easily, but the molding element is partially supported by unsintered powder which leads to manufacturing problems
Solution Approach 1:
The patent applies local quality by differentiating the support structure into two distinct zones: a first surface portion with a smaller angle (less than 20 degrees) that is entirely supported by secondary elements for easy detachment, and a second surface portion with a larger angle (20 degrees or more) that is partially supported by secondary elements and partially by unsintered powder for manufacturing stability. This spatial differentiation of support characteristics resolves the contradiction between ease of detachment and manufacturing reliability.
2Reliability
If extensive secondary elements are used to fully support the main element, then manufacturing stability is improved, but powder consumption increases and costs rise due to scrapping
Solution Approach 1:
The patent applies partial action by providing secondary elements that support only the first surface portion (entirely supported zone) rather than the entire lower surface of the main element. The second surface portion (partially supported zone) relies partly on unsintered powder for support. This partial support approach maintains manufacturing stability while reducing the quantity of secondary elements needed, thereby reducing powder consumption and scrapping costs.
3Ease of manufacture
If the lower surface is designed with angles less than 20 degrees, then detachment is facilitated, but support stability during manufacturing deteriorates
Solution Approach 1:
The patent segments the lower surface into two distinct angular zones: a first surface portion with an angle less than 20 degrees designed for easy detachment, and a second surface portion with an angle of 20 degrees or more designed for manufacturing stability. By segmenting the support strategy according to angular zones, the patent achieves both detachment facilitation and support stability without compromise.
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 enables efficient and cost-effective manufacturing by allowing partial support of the main element, reducing the amount of secondary elements required and enabling the reuse of unmelted powder, thus rationalizing the powder usage and improving the manufacturing process.
Implementation Method 1
a first layer of powder is spread on a support plate by a layering member. All or some of the particles of powder of this first layer of powder are then agglomerated by the laser beam according to the shape of the object that is to be obtained
Implementation Method 2
a sintering method using a laser, hereinafter referred to as a laser sintering method
Data Source
AI summary
A part obtained by selective melting of a powder on a support plate, this part comprising a main element and rigid secondary elements, these secondary elements supporting the main element between a lower surface of this main element and the support plate. Secondary elements are intended to be detached from the main element. The lower surface of the main element thus comprises a first surface portion and at least one second surface portion, and the first surface portion makes, with the support plate, an angle α1 of less than a predetermined value, and the second surface portion makes, with this support plate, an angle α2 greater than or equal to this predetermined value. The first surface portion is therefore entirely supported by the secondary elements and the second surface portion is partially supported by the secondary elements. The predetermined value is between 20° and 30°.