Laminate Molding Powder Evaluation Using Shear-Test Adhesive Force
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Solution Overview
Problem
The measurement of fluidity using JIS Z 2502 is unstable for lamination shaping powders, making it difficult to evaluate fine powders and ensuring consistent evaluation criteria, as slight changes in the measurement environment can prevent the measurement of powders that are potentially usable for lamination shaping.
Innovation Solution
The method evaluates the flowability of lamination shaping powders using the adhesive force calculated from a shear test, providing a stable criterion by measuring shearing stress and determining the failure envelope, which is more reliable than traditional flow rate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fluidity measurement using JIS Z 2502 is performed, then flowability evaluation is provided, but measurement stability deteriorates due to environmental sensitivity and inability to measure fine powders
Solution Approach 1:
The invention changes the measurement parameter from flow rate (JIS Z 2502) to adhesive force derived from shear test data. This parameter transformation enables stable measurement of fine powders that cannot be measured by traditional flow rate methods, and eliminates environmental sensitivity issues while maintaining evaluation accuracy
Solution Approach 2:
The invention replaces the mechanical flow rate measurement system with a shear test-based adhesive force measurement system. This substitution uses shear stress measurements and failure envelope analysis to evaluate powder flowability, providing reliable results for fine powders regardless of environmental conditions
2Device complexity
If traditional flow rate measurement is used, then evaluation process is simple, but evaluation reliability deteriorates for lamination shaping powders
Solution Approach 1:
The invention transforms the evaluation parameter from flow rate to adhesive force, maintaining relatively simple measurement procedures while dramatically improving reliability for lamination shaping powder evaluation. The shear test methodology remains straightforward but provides scientifically superior evaluation criteria
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 allows for stable evaluation of lamination shaping powders, enabling the identification of suitable powders for uniform layer formation and ensuring high-density, homogeneous products with improved flowability and reduced defects.
Implementation Method 1
the adhesive force of the powder calculated from a failure envelope obtained by a shear test
Data Source
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AI summary
This invention relates to a method of evaluating powder for lamination shaping by stable criteria. In this method, it is evaluated whether powder for lamination shaping can be spread into a uniform powder layer in the lamination shaping, wherein the powder is evaluated using, as a flowability of the powder, an adhesive force of the powder calculated from a failure envelope obtained by a shear test.. The shear test is conducted by a powder rheometer, and the adhesive force is obtained from the relationship between a normal stress and a shearing stress at the powder rheometer. If the adhesive force is 0.450 kPa or less, the powder is evaluated to be spread into a uniform powder layer in the lamination shaping. Furthermore, if at least one of that the 50% particle size of the powder obtained by a laser diffraction method is 3 to 250 µm and that the apparent density of the powder is 3.5 g/cm3 or more is satisfied, the powder is evaluated to be spread into a uniform powder layer in the lamination shaping.