3D printed mechanical testing device for micro-scale material specimens
Inventors
Kang, Wonmo • Rudolf, Christopher
Assignees
Publication Number
US-11609084-B2
Publication Date
2023-03-21
Expiration Date
2041-02-24
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Abstract
A system for mechanical testing a specimen includes a 3D printed mechanical testing fixture; a linear actuator having an axis of movement; a controller configured to control the linear actuator; two cameras; a data-acquisition system configured to acquire data from the linear actuator, the controller, and the two cameras; and the specimen. The specimen is marked in two locations with tracking markers to provide indication to the data acquisition system via at least one camera of movement and change in length of the specimen. The fixture includes force-sensing beams extending perpendicular to the axis of force.
Core Innovation
The invention described is a system for mechanical testing of micro-scale specimens using a 3D printed mechanical testing fixture combined with a linear actuator, a controller, two cameras, and a data-acquisition system. The specimen is marked with tracking markers at two locations to provide movement and change in length data via at least one camera. The mechanical testing fixture includes force-sensing beams extending perpendicular to the axis of force, and the system is capable of tuning the force range dynamically for different sample strengths.
This invention addresses problems found in conventional mechanical testing systems for micro-/nano-scale specimens, which typically either use expensive, proprietary software reliant, mm-scale systems or costly and time-consuming microelectromechanical systems (MEMS)-based fabrication or machining methods such as waterjet or wire electro discharge machining. These conventional methods are expensive, time-intensive, and lack flexibility for sample-specific needs. The invention leverages rapid 3D printing methods for low-cost fabrication allowing rapid customization of beam geometries to achieve prescribed force-displacement ranges and enables the acquisition of stress-strain curves within an uncommon force range, highlighting high throughput analysis capability for different material conditions.
Claims Coverage
The patent contains two independent claims covering a system for mechanical testing a specimen and a mechanical testing fixture. Each claim introduces inventive features related to configuration, components, and customization capabilities.
Mechanical testing system with 3D printed fixture and synchronized data acquisition
The system includes a 3D printed mechanical testing fixture, a linear actuator along an axis of movement controlled by a controller, and two cameras. A data-acquisition system collects data from the actuator, controller, and cameras. The specimen is marked at two locations with tracking markers allowing the data-acquisition system to detect movement and length change via at least one camera.
Mechanical testing fixture with force sensing beams and thickened base
The fixture comprises first and second sides with a testing axis extending between them, each side configured to hold specimen ends. The first side includes force sensing beams extending perpendicular to the axis and has a base portion thickened relative to the beams to increase rigidity. The fixture is 3D printed and constructed with parameters ensuring coherence of force sensing beams tightly integrated with a relatively stiff support structure. The second side contains support beams soft in the pulling direction but stiff in other directions. Beams are designed for a target sensor deflection between 20-120 μm and targeted force sensing capability between 5 mN and 35 mN. The force range is configurable by altering stiffness of force sensing beams by changing length, thickness, or material.
The claims collectively cover a system and fixture for micro-scale mechanical testing employing a 3D printed fixture with integrated force sensing beams, a controlled actuator, dual-camera tracking for specimen displacement and strain, and customizable mechanical properties to provide precise and low-cost testing within micro-scale force ranges.
Stated Advantages
Low-cost and rapid fabrication of micro-scale mechanical testing devices using 3D printing, enabling sample-specific customization of force-displacement ranges.
Capability to obtain stress-strain curves for micro-scale systems in an uncommon force range (5 mN to 35 mN) which has traditionally been neglected.
The fixture design with force sensing beams integrated reduces overall device cost by eliminating the need for expensive external high sensitivity force sensors.
The vertical mounting of the testing device provides self-alignment of the specimen and reduces undesirable loads during handling.
High throughput analysis capability for comparison of different material conditions is facilitated by the design.
Documented Applications
Mechanical tensile testing of micro-scale specimens including wires fixed in series between fixture sides.
Mechanical testing in bending modes, including 3-point bending and 4-point bending tests using configured testing fixtures applying compressive bending forces.
Compression testing using dedicated compression test fixtures applying compressive forces in a controlled manner.
Testing inside scanning electron microscopes (SEM) for increased deformation characterization under ambient or specialized conditions.
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