Lamination Shaping Powder Evaluation Using Shear-Test Adhesive Force
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Solution Overview
Problem
The measurement of fluidity using JIS Z 2502 for lamination shaping powders is unstable, making it difficult to evaluate fine powders and ensuring consistent criteria for their evaluation.
Innovation Solution
Evaluating the flowability of lamination shaping powders using the adhesive force calculated from a shear test, which provides stable measurement results and is combined with other evaluation targets to assess their suitability for uniform layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fluidity measurement complying with JIS Z 2502 is used for evaluating lamination shaping powder, then the evaluation can be performed using a standard method, but the measurement results are unstable and cannot reliably evaluate fine powders
Solution Approach 1:
The patent changes the measurement parameter from fluidity (JIS Z 2502) to adhesive force measured by shear test. This parameter change enables stable evaluation of fine powders that cannot be properly evaluated by conventional fluidity measurement, resolving the contradiction between measurement stability and evaluation reliability.
2Ease of manufacture
If conventional fluidity measurement is used, then the measurement process is simple and standardized, but fine powders cannot be measured or results vary with slight environmental changes
Solution Approach 1:
The patent transitions from measuring fluidity to measuring adhesive force through shear test. This parameter change maintains measurement simplicity while achieving consistent results for fine powders, resolving the contradiction between ease of measurement and measurement consistency.
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 method allows for stable evaluation of lamination shaping powders, ensuring that only powders with sufficient squeegeeing properties are used, leading to high-density, homogeneous products with improved flowability and reduced defects.
Implementation Method 1
a shearing stress measurement unit 200 for measuring a shearing stress
Data Source
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.