Z-axis Test Coupon Structure for Additive Manufacturing
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Solution Overview
Problem
The additive manufacturing industry lacks a standard method for producing Z-axis (vertical) tensile bar coupons, which are crucial for testing the mechanical properties of parts fabricated using processes like FDM, due to the inherent weakness of Z-axis orientation in these technologies, limiting their adoption in aerospace and other applications.
Innovation Solution
A Z-axis test coupon structure featuring a circular arrangement of tensile specimens connected by removable webs, allowing for the assessment of tensile strength and optimization of material laydown, and a method for developing consistent material allowables through statistical analysis and Design of Experiments to enhance mechanical property performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If Z-axis orientation is used in additive manufacturing, then the part can be built vertically, but the mechanical strength is reduced due to the additive nature of the process
Solution Approach 1:
The test coupon is divided into multiple tensile specimens arranged in a circular pattern, with each specimen oriented at different angles (0°, 45°, 90°, 135°) relative to the build direction. This segmentation allows independent testing of each orientation's mechanical properties while maintaining a unified test structure.
Solution Approach 2:
The test coupon employs asymmetric web structures connecting the tensile specimens at different radial distances from the center. The first webs connect specimens at a first radial distance while the second webs connect specimens at a second radial distance, creating an asymmetric configuration that accounts for varying stress distributions in different orientations.
2Reliability
If multiple tensile specimens are tested to assess Z-axis strength, then the mechanical property data becomes more comprehensive, but the testing time and complexity increase
Solution Approach 1:
Multiple tensile specimens oriented at different angles are combined into a single integrated test coupon structure. The circular arrangement with web connections allows all specimens to be manufactured and tested as one unit, reducing the time required compared to manufacturing and testing each specimen separately.
Solution Approach 2:
The test coupon structure serves multiple functions simultaneously: it provides support for all tensile specimens, enables testing of multiple orientations (0°, 45°, 90°, 135°), and allows assessment of both uniaxial tensile and flexural properties through a single standardized structure.
3Strength
If support structure is used in additive manufacturing processes, then the Z-axis orientation strength is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The test coupon design extracts and eliminates the need for separate support structures by incorporating the support function directly into the coupon's web structure. The webs themselves provide the necessary support for the tensile specimens during manufacturing, simplifying the overall process by removing the support structure step.
Solution Approach 2:
The web structure serves dual purposes: it connects the tensile specimens to each other and provides support during the additive manufacturing process. This multi-functionality eliminates the need for separate support structures, reducing manufacturing complexity while maintaining Z-axis orientation strength.
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 solution enables the production of standardized Z-axis test coupons that improve build efficiency, reduce material usage, and provide consistent mechanical property data, facilitating the selection of candidate parts and optimizing additive manufacturing processes for aerospace and other demanding applications.
Implementation Method 1
FDM is a nonlaser filament extrusion process that may utilize engineering thermoplastics, which may be heated from filament form and extruded in very fine layers to build each model from the bottom up
Implementation Method 2
The material used is fed into an extrusion head in solid wire form and then liquefied in the extrusion head and deposited through a nozzle in liquid form
Data Source
AI summary
A Z-axis test coupon structure and method for additive manufacturing process are disclosed. An example method of fabricating Z-axis test coupons for additive manufacturing processes, includes fabricating tensile specimens, the fabricating of the tensile specimens including providing a web between adjacent ones of the tensile specimens, and the fabricating of the tensile specimens including using an additive manufacturing process, removing the web from between the adjacent ones of the tensile specimens, and testing a tensile strength of one of the tensile specimens.