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Current industrial applications
The DiAMon Plus™ dielectric cure monitoring system and sensors have been implemented to a series of composites manufacturing methods, such as RTM, RTI (in autoclave) and pultrusion. For each manufacturing environment, there are appropriate sensor housing adaptations and wiring configurations. The length of wires connecting the sensor to the measurement unit ranges from 0.5 m to 22 m in the current applications. The sensor mounts are vacuum tight and their pressure resistance is up to 20 bar.

i. RTM Installation
The dielectric sensor elements are mounted in cylindrical housings for adaptation to the RTM mould. The sensors are equipped with O-ring near the active surface and with screw nut at the rear side for convenience of extraction rom the mould. The installation has been performed with success at several manufacturing sites. The sensors showed excellent survivability (>50 mould fillings) given the proper maintenance, cleaning and release according to the current tool preparation practice.
 
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System installation in RTM (left) and integrated sensor for flow and cure monitoring (right)
 
ii. RTI Installation
For the operation of the dielectric monitoring system in RTI processing, the tool inside the autoclave is instrumented with dielectric sensors while the autoclave inlet ports are modified to accommodate glands for passing coaxial high temperature wiring through the shell.
The sensor operation in RTI processing provides real-time information to the operator concerning the time of resin arrival on the sensor, the viscosity changes during tool filling, the onset of reaction during tool heating, the gelation point and finally the end-cure point. Additional modelling of the resin system is utilised to measure in real-time the degree of cure and Tg of the resin, thus allowing the determination of the final properties of the resin during processing.
 
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1: INASCO monitoring system in front of autoclave, 2: tool mounted sensor,
3: underside, 4: inside and 5: outside of autoclave
 
iii. Pultrusion Installation
For the operation of the dielectric monitoring system in pultrusion processing, a highly abrasive resistant sensor element was developed.  The sensor was adapted to the die exit via a special mounting mechanism to allow the sensor to stay in contact with the profile as it exits the die while the sensor is not disturbed by vibrations caused by the pullers and cutters.
The industrial installation to pultrusion line involves a series of dielectric sensors to the corresponding dies, a console with temperature controllers and line speed recording, the dedicated software for data acquisition and storage, and the material modelling for the direct continuous measurement of the resin viscosity in the bath and the profile Tg at the die exit. The complete system installation has been certified for use in aerospace grade manufacturing of composites via pultrusion. 
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1: INASCO control system next to pultrusion line, 2: mounted sensor,
3: sensor adapted to die exit, 4: DiAMon plusTM software and 5: multiple sensors

iv. Sensor Installation in resin pot/bath
For the operation of the dielectric monitoring system in resin containers, a specific air tight sensor mounting has been developed. The sensor is immersed in the resin container and continuously monitors the resin resistivity and temperature. For each resin system there is a master curve correlating the resin electrical properties to viscosity. Such a curve is defined at lab scale tests. The DiAMon Plus™ system provides real-time viscosity information, which can be extremely significant for a range of Liquid Composite Moulding processes. For example, in pultrusion the resin bath sensor indicates when the resin needs to be replenished or to be slightly heated in order to reduce viscosity and facilitate fibre wetting before entering the die. Also in RTM or RTI processing, the resin pot sensor qualifies the resin condition for a successful injection. This is accomplished by establishing a limiting viscosity value that the resin can reach in the mould without preventing complete wetting of the fabric or of the preform. The dielectric sensors are integrated in RTM resin pots in collaboration with injection control equipment manufacturers (i.e. ISOJET Equipement).
 
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