Condition monitoring for preventive maintenance with integrated detection

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There is a significant need to integrate many heterogeneous technologies to enable robust monitoring of structural health for preventive maintenance or to better control feedback from integrated mobile actuation mechanisms and adaptive objects.

This is also essential for moving additive manufacturing (AM) beyond cutting-edge topology optimization technologies, where it is essential to develop concepts and technologies that can facilitate these additional functionalities while maintaining versatility and reliability. flexibility at the heart of AM. .

CHAMELEON aims to support the use of developing technologies in the fabrication of metal-based 3D parts with embedded features, for example:

  • Electric and pneumatic crossings
  • Sensors
  • Actuators

It aims to achieve this using a combination of:

  • Advanced design
  • Inkjet printing (IJP)
  • AerosolJet printing (AJP)
  • Polymer casting
  • Powder bed laser fusion (L-PBF)
  • Surface post-treatment

CHAMELEON’s primary applications focus will be on markets already employing AM in production settings where users have requested additional functionalities.

Additive Manufacturing Benefits

AM is becoming increasingly central to the production of high-end components in the aeronautics, space and medical fields.

The critical needs of these industries can be met using the features available from AM, in particular AM’s capacity to produce components with complex geometries at moderate production volumes, as well as the weight reduction afforded by AM’s topology optimization.

Despite this, many AM applications are based on the manufacture of ‘passive’ elements with no functionality beyond their mechanical structure.

To continue to enhance AM’s market attractiveness, it is necessary to develop the technological foundations of new and ‘active’ AM functionalities, prompting CSEM to investigate the use of combined 3D printing and 2D printing to generate 3D compliant mechanisms with embedded sensors suitable for use in complex AM-based mechatronics devices.

Several key technology milestones have been demonstrated thus far.

It has been possible to achieve high precision and low stress stainless steel 17-4PH L-PBF manufacturing with high fatigue resistance, using this to manufacture flexure blades down to 0.1 mm and with a 45° angle.

The electrical wiring throughout the structure was also fabricated as part of this manufacturing phase.

It has also been possible to offer advanced surface polishing of the L-PBF structures down to 100 nm to ensure suitability for sensor printing.

Notable advances have been made in the 2D printing (InkJet or AerosolJet Printing) of a conductive and an insulation layer to form the strain sensor, with sensor performances currently including:

  • Gauge factor (sensitivity) greater than 2 – greater than or equivalent to a commercial thin film metal strain gauge
  • Linearity better than 99.9%
  • 100% efficiency
  • ± 15% variation in R within a batch – providing the ability to produce thermally compensated strain gauges using a Wheatstone bridge

Figure 1. Insulation and strain gauge printed by AerosolJet Printing on a flexible element 300 m thick. Image Credit: CSEM

AerosolJet Printing strain gauge performance for different printing and / or curing conditions.

Figure 2. AerosolJet Printing strain gauge performance for different printing and / or curing conditions. Image Credit: CSEM

A first demonstrator was manufactured, with a ± 5 mm stroke XY stage with a laser attached to the exit platform.

High-precision linear motion is achieved through the integration of 300 µm thick bending elements, which have integrated electrical wires. These wires feed both the laser source and provide a suitable interface for the printed strain sensors.

The overall structure represents a total volume of approximately 80x50x80 mm3, while the demonstrator is actuated by servomotors. The integration of the sensors is currently underway.

3D printed XY stage with integrated sensor and external actuator.  A laser pointer is integrated into the mobile platform to illustrate the demonstrator's ability to power a device using flexible blades.

Figure 3. 3D printed XY stage with integrated sensor and external actuator. A laser pointer is integrated into the mobile platform to illustrate the demonstrator’s ability to power a device using flexible blades. Image Credit: CSEM

A new material has also been developed via L-PBF, offering a low CTE (

Thanks

Produced from materials originally written by S. Lani, N. Hendricks, S. Zabihzadeh, G. Perruchoud, L. Kiener, F. Cosandier, N. Marjanovic, J. Disser of the Swiss Center for Electronics and Microtechnology.

This information was obtained, reviewed and adapted from documents provided by CSEM.

For more information on this source, please visit CSEM.


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