Sensor Integration in Castings Made of Aluminum - New Approaches for Direct Sensor Integration in Aluminum High Pressure Die Casting

Abstract

The use of sensors for detection, measurement and evaluation of mechanical and thermal loads is well known and essential for the implementation of »Structural Health Monitoring« (SHM). For this, sensors are mainly used for condition monitoring of mechanical loads and their impact to the castings state, which is a decisive advantage for safety-related components. The use of sensors on the surface of metallic components, in particular of cast metal components made of aluminum, is still limited to the use of strain gauges. They are usually applied on the surface of the cast metal components and get fixed by adhesives. The idea is, to integrate the sensors directly during the aluminum casting process. Since integrated sensors are naturally protected against chemical and mechanical influences, furthermore the load can be measured directly at the point of interest inside the component. Measurement data can be recorded and provide a good data basis for future calculations and dimensioning of components, which is known as »Data Mining« or »Industrial Data Space«. New technology and material combinations, which allow the fabrication of sensors capable of withstanding force and temperature during the integration process in aluminum casting, are investigated.In this paper, the design and fabrication of a strain gauge printed on an aluminum sheet is shown. These sensor sheets get integrated in aluminum during high pressure die casting (HPDC) in a way that a specimen is build up. The specimen is characterized in a fatigue bending test and the sensor data was read permanently during this test. It is shown that the new approach with printed thick film sensors on aluminum substrate sheets works properly to withstand the heavy thermal conditions during high pressure die casting. The fabricated sensor is able to sense the mechanical tiredness and detects the fatigue of the metal matrix. This a first step to use such material integrated sensors in structural health monitoring applications.

Sensor-integrated structures in mechanical engineering: challenges and opportunities for mechanical joining processes

“…The molten metal is injected under pressure into a mold cavity. The pressure is maintained until complete solidification is reached [12]. In the field of the sensor embedding into die-cast parts, they present an approach whereby thickfilm strain gauge transducers are integrated into aluminium die casted parts using the high-pressure die-casting process (HPDC).…”

“…In the field of the sensor embedding into die-cast parts, they present an approach whereby thickfilm strain gauge transducers are integrated into aluminium die casted parts using the high-pressure die-casting process (HPDC). To protect the sensing element from the high casting temperature and pressure of the HPDC machine, the thick film sensors are covered with several protective layers and with a high temperature silicone film [12], as in Fig. 3.…”

“…Thermal insulation covers the thick-film strain gauge sensor (left). Sensor after integration (right) [12] Fig. 4 a Percentage concentration profile of fiber core composition and b optical microscope image of a fiber cross-section [21].…”

In-process calibration of smart structures produced by incremental forming

“…The combination of a highly enriched thermoplastic polymer with piezo ceramic powder and thin metal sheets by combining extrusion and rolling [3] or the embedding of FBG sensors in civil engineering structures based on various technologies [4] are further examples of research work within this field. Other investigations center around the integration of piezoelectric transducers [5] and strain gauge-based sensors [6] into metallic structures by high pressure die casting, or around the integration of fiber optics on metallic structures by TIG welding [7].…”

Thick Film Sensor Manufacturing Techniques for Realization of Smart Components via Low Pressure Die Casting

“…Related studies on integration of thick film sensors in high pressure die casting (HPDC) of aluminum alloys have previously been performed by our working groups [3] [4] [6]. In this process, roughly ¾ of the sensors survived the casting process.…”