Sustainable injection moulding: The impact of materials selection and gate location on part warpage and injection pressure

This paper presents an approach of how warpage (i.e. part deflection) and injection pressure of an intricate geometry could be minimised by selecting an optimal thermoplastic material and injection gate location (through which the molten plastic flows into the cavity). The numerical analyses for mould filling considered four gate locations along with a PP (polypropylene), PS (polystyrene) and a fibre-filled PP material (each had different shrinkage characteristics, mechanical property and viscosity). Results of the cavity filling simulations indicated that (on average) the largest and smallest warpage was predicted with the PP and PS respectively. The warpage of the fibre-filled PP showed the most gate location dependent behaviour. In addition, the lowest injection pressure was associated with the fibre-filled PP. For reduced pressure, the best and second best solutions for gate location were the top and middle ones. In addition, specific attention was paid to differential fibre orientation, as one of the most important factors responsible for part warpage. In an attempt to maximise the part stiffness, the fibre-filled PP was selected. It became clear that the gate location affected the melt flow evolution and therefore the fibre orientation. Simulation results showed that bidirectional flow and asymmetrical fibre distribution was achieved with the gate positioned at the mid-section of the part. Unidirectional flow and therefore symmetrical fibre distribution could be achieved by placing the gate at the top section of the part. The injection moulding experimental utilised the fibre-filled PP along with the two aforementioned gate locations. It was discovered that warpage was present when the middle gate was applied, but it was successfully eliminated using the top gate location. It can be stated that differential fibre orientation did not cause warpage, but the asymmetrical distribution of fibre orientation did. The information discussed in the paper may be particularly useful in the early mould/part design stages when any modification can still be easily and cost-effectively implemented. An important finding is that the final gate location should only be chosen after the thermoplastic material properties and melt flow direction have been taken into account. The successful reduction of warpage and injection pressure may help to reduce the amount of production waste and energy consumption, ensuring defect-free sustainable manufacturing

Efficacy of 3D visualization in mobile apps for patient education regarding orthognathic surgery

‘Sur-face’ is an interactive mobile app illustrating different orthognathic surgeries and their potential complications. This study aimed to evaluate the efficacy of Sur-face by comparing two methods of delivering patient information on orthognathic surgeries and their related potential complications: a mobile app with interactive 3D animations and a voice recording containing verbal instructions only. For each method, the participants’ acquired knowledge was assessed using a custom-designed questionnaire. Participants in the ‘app’ group performed significantly better (P<0.0034) than those in the ‘voice’ group and retained more knowledge, suggesting that interactive visualizations play a key role in improving understanding of the orthognathic surgical procedure and its associated complications. This study emphasizes the impact of 3D visualizations in delivering information regarding orthognathic surgery and highlights the advantage of delivering validated patient information through mobile apps

Structural sustainability appraisal in BIM

The provision of Application Programming Interface (API) in BIM-enable tools can contribute to facilitating BIM-related research. APIs are useful links for running plug-ins and external programmes but they are yet to be fully exploited in expanding the BIM scope. The modelling of n-Dimensional (nD) building performance measures can potentially benefit from BIM extension through API implementations. Sustainability is one such measure associated with buildings. For the structural engineer, recent design criteria have put great emphasis on the sustainability credentials as part of the traditional criteria of structural integrity, constructability and cost. This paper examines the utilization of API in BIM extension and presents a demonstration of an API application to embed sustainability issues into the appraisal process of structural conceptual design options in BIM. It concludes that API implementations are useful in expanding the BIM scope. Also, the approach including process modelling, algorithms and object-based instantiations demonstrated in the API implementation can be applicable to other nD building performance measures as may be relevant to the various professional platforms in the construction domain

Streamlining Digital Modeling and Building Information Modelling (BIM) Uses for the Oil and Gas Projects

The oil and gas industry is a technology-driven industry. Over the last two decades, it has heavily made use of digital modeling and associated technologies (DMAT) to enhance its commercial capability. Meanwhile, the Building Information Modelling (BIM) has grown at an exponential rate in the built environment sector. It is not only a digital representation of physical and functional characteristics of a facility, but it has also made an impact on the management processes of building project lifecycle. It is apparent that there are many similarities between BIM and DMAT usability in the aspect of physical modeling and functionality. The aim of this study is to streamline the usage of both DMAT and BIM whilst discovering valuable practices for performance improvement in the oil and gas projects. To achieve this, 28 BIM guidelines, 83 DMAT academic publications and 101 DMAT vendor case studies were selected for review. The findings uncover (a) 38 BIM uses; (b) 32 DMAT uses and; (c) 36 both DMAT and BIM uses. The synergy between DMAT and BIM uses would render insightful references into managing efficient oil and gas’s projects. It also helps project stakeholders to recognise future investment or potential development areas of BIM and DMAT uses in their projects

Automated Planning of Concrete Joint Layouts with 4D-BIM

Concrete pouring represents a major critical path activity that is often affected by design limitations, structural considerations and on-site operational constraints. As such, meticulous planning is required to ensure that both the aesthetic and structural integrity of joints between cast in-situ components is achieved. Failure to adequately plan concrete pouring could lead to structural defects, construction rework or structural instability, all having major financial implications. Given the inherent complexity of large-scale construction projects, the ‘manual planning’ of concrete pouring is a challenging task and prone to human errors. Against this backdrop, this study developed 4D Building Information Management (BIM) approach to facilitate automated concrete joint positioning solution (as a proof of concept) for design professionals and contractors. The study first developed structural model in Revit, then extracted spatial information regarding all construction joints and linked them to dynamic Microsoft (MS) Excel and Matlab spreadsheets using integration facilitated by Dynamo software. Midspan points of each beam as well as floor perimeter information were gathered via codes developed in MS Excel macros. Based on the Excel outputs, Matlab programming was used to determine best concreating starting points and directions, and daily allowed concrete volume, considering limitations due to cold joints. These information were then pushed back to Revit via Dynamo in order to develop daily concrete scheduling. The developed automated programme framework offers a cost-effective and accurate methodology to address the limitations and inefficiencies of traditional methods of designing construction joints and planning pours. This framework extends the body of knowledge by introducing innovative solutions to integrate structural design considerations, constructional procedures and operational aspects for mitigating human error, and providing a novel, yet technically sound, basis for further application of BIM in structural engineering