3D Printing Double-Pass Coating for Uniform Sintering
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Solution Overview
Problem
Existing methods for producing three-dimensional objects by layer-wise solidification of powder materials face challenges in achieving uniform temperature distribution and quality, particularly in rapid prototyping and additive manufacturing, where selective laser sintering or melting techniques often result in incomplete solidification and temperature inhomogeneities.
Innovation Solution
A method and device that coordinate the motion of an application device and an irradiation device to apply and solidify powder layers in a way that the application device moves twice over an area without energy introduction and the irradiation device moves twice over an area without new material application, allowing for double coating and double exposure, which enhances temperature homogenization and complete solidification by separating the energy required into two sub-exposures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If selective laser sintering or melting is used to produce three-dimensional objects layer by layer, then rapid prototyping and additive manufacturing capabilities are achieved, but incomplete solidification and temperature inhomogeneities occur in the produced objects
Solution Approach 1:
The patent divides a single powder layer application and irradiation step into multiple sub-steps: the powder layer is applied in multiple passes (at least two) by the application device, and the irradiation device also performs multiple passes (at least two) over the same area. This segmentation allows each pass to contribute partially to solidification, ensuring complete and uniform solidification across the entire layer without compromising production speed.
Solution Approach 2:
The patent implements periodic action by repeating the application and irradiation cycles multiple times. The application device moves back and forth over the powder area in periodic passes, and the irradiation device similarly performs periodic irradiation passes. This periodic repetition ensures that each region receives sufficient energy input for complete solidification while maintaining a controlled rhythm that prevents temperature inhomogeneities.
2Speed
If energy is introduced continuously during powder layer application, then solidification speed increases, but temperature distribution becomes inhomogeneous and quality decreases
Solution Approach 1:
The irradiation process is segmented into multiple separate passes rather than one continuous irradiation. Each pass irradiates a portion of the powder layer, and the cumulative effect of multiple passes achieves complete solidification. This segmentation distributes the energy input over time and space, preventing localized overheating while ensuring uniform temperature distribution across the entire layer.
Solution Approach 2:
The application device performs multiple passes to apply the powder layer completely before the irradiation device begins its irradiation passes. This preliminary complete application ensures that the entire powder layer is in place and ready for uniform irradiation, preventing situations where some regions receive energy before powder is fully applied, which would cause temperature inhomogeneities.
3Productivity
If the application device and irradiation device operate simultaneously at different positions, then process speed increases and production time decreases, but coordination complexity increases
Solution Approach 1:
The simultaneous operation is segmented into discrete, repeatable cycles where both devices perform multiple passes over the same area. Each device operates independently in its own passes, but the segmented structure allows for straightforward coordination through simple cycle repetition. This segmentation reduces coordination complexity compared to attempting continuous simultaneous operation across the entire area in a single pass.
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 improves the mechanical properties and surface quality of the produced objects by ensuring complete solidification and reducing production time, while also allowing for simultaneous operation of the application and irradiation devices, increasing process speed and reducing production costs.
Implementation Method 1
selective irradiation with a laser beam
Implementation Method 2
DE 10 2012 212 587 describes a device and a method for producing a three-dimensional object layer by layer by laser sintering
Implementation Method 3
An example of such a method is known by the name 'selective laser sintering or laser melting'
Data Source
AI summary
A method for producing a three-dimensional object by layer-wise applying and selectively solidifying a building material in powder form includes the steps of applying a layer of the building material over a working plane and selectively solidifying the layer at positions that correspond to a cross-section of the object to be produced by introducing energy and repeating the steps of applying and selectively solidifying until the object is completed. By doing so, the application step is carried out such that the application device moves at least twice over an area to be coated without an intermediate irradiation, and the step of selectively solidifying is carried out with an irradiation device that emits a radiation suited to solidify the building material.