3D Powder Bed Fusion Surface Scanning for Smoother Parts
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Solution Overview
Problem
Existing additive layering processes result in undesirable surface roughness, necessitating complex mechanical post-processing to achieve smooth surfaces, particularly on the bottom and top surfaces of manufactured objects.
Innovation Solution
A method involving multiple irradiations of surface areas before and, in some cases, after scanning the interior region during layer-by-layer solidification, using electromagnetic or particle radiation to induce local bonding through superficial melting, ensuring smoother surfaces without additional mechanical processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single irradiation is used to solidify the applied layer, then the manufacturing process is efficient and fast, but the surface quality is poor with undesirable roughness
Solution Approach 1:
The irradiation process is segmented into multiple passes: a first irradiation to solidify the applied layer, and a second irradiation specifically targeting the surface region. This segmentation allows the bulk material to be processed efficiently while the surface receives additional treatment for improved quality, resolving the contradiction between manufacturing speed and surface precision.
Solution Approach 2:
The surface region is irradiated a second time before subsequent layers are applied, ensuring that the surface quality is established in advance. This preliminary action on the surface region prevents roughness from developing in later layers, maintaining high surface quality without requiring extensive post-processing.
2Manufacturing precision
If the surface region is irradiated multiple times, then surface roughness is reduced, but the energy consumption increases
Solution Approach 1:
The second irradiation is applied selectively only to the surface region, not the entire applied layer. This localized treatment concentrates energy where it is most needed for surface smoothness while minimizing unnecessary energy consumption in the bulk material, resolving the contradiction between surface quality and energy efficiency.
3Manufacturing precision
If mechanical post-processing is applied to achieve smooth surfaces, then surface quality is improved, but the complexity and time of the manufacturing process increases
Solution Approach 1:
The patent replaces mechanical post-processing operations with an additional irradiation step during the manufacturing process. By using electromagnetic radiation to achieve surface smoothness in-situ, the need for separate mechanical polishing or finishing operations is eliminated, reducing process complexity while maintaining high surface quality.
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 method achieves significantly smoother surfaces with reduced need for mechanical post-processing, particularly noticeable on metallic objects, enhancing surface gloss and reducing roughness, especially on objects with high precious metal content.
Implementation Method 1
the powder is at least superficially melted at these locations by the heat energy introduced by the radiation
Implementation Method 2
a local temperature is induced in the area of influence of the electromagnetic or particle radiation on the build-up material, which causes a local bonding effect in the build-up material (e.g., through at least superficial melting, sintering, or similar)
Implementation Method 3
selectively solidifying the applied layer by means of electromagnetic radiation or particle radiation
Implementation Method 4
the powder is at least superficially melted at these locations by the heat energy introduced by the radiation
Implementation Method 5
the powder is at least superficially melted at these locations by the heat energy introduced by the radiation
Data Source
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AI summary
A method for producing an object (3) by means of layered compacting of a powdered starting material (11) by electromagnetic radiation or particle radiation comprises a step of applying a layer of the building material (11) to a building base (2) or an already previously applied and selectively compacted layer and a step of selectively compacting the applied layer by means of electromagnetic radiation or particle radiation, in which all of the locations in the layer that correspond to a cross section of the object (3) are scanned by means of electromagnetic radiation or particle radiation such that the powder at these locations is at least superficially melted. In this case, at least one cross section consists of an inner region (63) and a surface region (60). The step of applying a layer and the step of selectively compacting the layer are repeated as often as it takes for all the cross sections of the object to be compacted, in at least one of the selective compacting steps at least part of the surface region (60) being scanned at least twice before the beginning of the scanning of the inner region (63).