Ultrasound Tomography for Spatially Resolved Melt Temperature Measurements in Injection Moulding ProcessesHopmann C and Wipperfürth J*
Institute of Plastics Processing (IKV), RWTH Aachen University, Seffenter Weg 201, 52074 Aachen, NRW, Germany
- *Corresponding Author:
- Jens Wipperfürth
Institute of Plastics Processing (IKV), RWTH Aachen University
Seffenter Weg 201, 52074 Aachen, NRW
Tel: +49 241 80 28364
E-mail: [email protected]
Received date: March 08, 2017; Accepted date: May 22, 2017; Published date: May 26, 2017
Citation: Hopmann C, WipperfÃ¼rth J (2017) Ultrasound Tomography for Spatially Resolved Melt Temperature Measurements in Injection Moulding Processes. J Appl Mech Eng 6: 264. doi: 10.4172/2168-9873.1000264
Copyright: © 2017 Hopmann C, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
In injection moulding processes, the measurement of the temperature distribution is very important for the validation of models used for simulative part design due to the high influence on shrinkage and warpage of the moulded part, but is also very challenging to measure. During the injection moulding process high mould pressures occur and the cavity is not easily accessible. Therefore, contact sensors cannot be used since they induce shear stress into the melt, which changes the flow behaviour of the melt and thus the temperature field. In this work, we present a method for the contactless determination of the temperature distribution of a moulded part during injection moulding using ultrasound tomography. With time-of-flight ultrasound measurements from different directions it is possible to reconstruct the distribution of ultrasound velocity in the cross-section of a moulded part. With this distribution, the temperature field can be calculated using additional material characteristic properties. Based on this concept, an injection mould was designed, that allows performing ultrasound tomography with 20 ultrasound transducers radially arranged around a cylindrical shaped cavity. This allows the temperature determination under real process conditions with a spatial resolution of 3.5 mm2. A highly parallelised measurement device allows recording of several complete datasets before no more signals can be detected due to shrinkage of the moulded part. During several injections moulding-cycles all sensor positions were able to detect noticeable signals. Due to internal signal processing of the measurement device, it is not yet possible to calculate arrival times of the ultrasound signal but amplitude-scans show the general feasibility of ultrasound tomography during injection moulding..