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- International Conference on Progress in Digital and Physical Manufacturing ProDPM'19 - Book of AbstractsPublication . Almeida, Henrique; Vasco, Joel; Marto, Anabela; Capela, Carlos; Freitas, Dino; Craveiro, Flávio; Bártolo, Helena; Coelho, Luís; Correia, Mário; Vieira, Milena; Ruben, RuiThe “Progress in Digital and Physical Manufacturing” book contains keynotes and papers presented at the first International Conference on Progress in Digital and Physical Manufacturing (ProDPM'19), organized by the School of Technology and Management (ESTG) of the Polytechnic Institute of Leiria (IPLeiria), from the 2nd to the 4th of October 2019. This international conference aims to provide a major international forum for the scientific exchange of multi-disciplinary and inter-organisational aspects performed by academics, researchers and industrial partners in order to exchange ideas in the field of digital and physical manufacturing and related areas. It represents a significant contribution to the current advances in industrial digital and physical manufacturing issues as it contains topical research in this field. The ProDPM'19 conference expects to foster networking and collaboration among participants to advance the knowledge and identify major trends in the field. The conference addresses to industrial challenges focused on current market demands and actual technological trends, such as mass customization, new business and industrial models or predictive engineering. Its contribution in science and technology developments leads to more suitable, effective and efficient products, materials and processes, generating added-value for the Industry and promoting the awareness of the role and importance of the digital and physical manufacturing development in the society. This book is, therefore, an essential reading for all of those working on digital and physical manufacturing, promoting better links between the academia and the industry. The conference papers will cover a wide range of important topics like additive manufacturing, biomanufacturing, advanced and smart manufacturing technologies, rapid tooling, microfabrication, virtual environments, simulation and 3D CAD and data acquisition, materials and collaborative design.
- Thermo-rheological behaviour of polymer melts in microinjection mouldingPublication . Vasco, Joel; Maia, J.M.; Pouzada, A.S.Microinjection has proven to be one of the most efficient replication methods for microcomponents and microsystems in various domains of microengineering. The use of available commercial microinjection equipment to evaluate the polymeric flow in microchannels would surely contribute to enhancing knowledge on polymeric flow at the microscale under industrial conditions. This approach is appropriate since rheological phenomena such as wall slip, surface tension, melt pressure drop and polymer flow length can be studied. These aspects are not fully dealt with in current commercial simulation software packages. In this study a micromould was designed to assess and characterize the flow in microchannels under realistic industrial conditions.
- PrefacePublication . Almeida, Henrique A.; Vasco, Joel C.The “Progress in Digital and Physical Manufacturing” book contains keynotes and papers presented at the first International Conference on Progress in Digital and Physical Manufacturing (ProDPM’19), organized by the School of Technology and Management (ESTG) of the Polytechnic Institute of Leiria (IPLeiria), from October 2 to 4, 2019. This international conference aims to provide a major international forum for the scientific exchange of multi-disciplinary and inter-organizational aspects performed by academics, researchers, and industrial partners in order to exchange ideas in the field of digital and physical manufacturing and related areas. It represents a significant contribution to the current advances in industrial digital and physical manufacturing issues as it contains topical research in this field.
- DMLS technology for automotive toolingPublication . Leal, R.; Barreiros, Fatima; Alves, M.L.; Romeiro, F.; Vasco, J.; Santos, M.; Marto, C.The automotive industry is challenged every day, with companies competing and developing new models and facelifts in short term, requiring new tools or tool reshaping. Concerning the current world economic scenario, decreasing time-for-tooling becomes as important as decreasing time-to-market. Such scenario opens up the horizons for new manufacturing approaches like additive manufacturing. In this case-study, additive manufacturing is applied for tooling up a stamping process for the production of body panels for the automotive industry. This approach enables the manufacturing of stamping tool inserts with similar high performance alloy steel as in conventional tooling, although, without any loss of tool properties and saving a significant part of the tool manufacturing time. The evaluation of the tool performance and tool life estimation was carried out based on three point bending fatigue tests using specimens manufactured by the same additive process and using the same powder material. From these data, it was possible to establish realistic scenarios for the use of additive tooling and to evaluate its feasibility on the automotive industry.
- A study on microinjection moulding using moulding blocks by additive micromanufacturingPublication . J C Vasco; Pouzada, A. S.Microinjection moulding is one of the most efficient replication methods for polymeric components in microsystems. The manufacturing of moulding blocks for complex geometries is resorting increasingly to the techniques of rapid prototyping. This development on the use of additive microtechnologies can promote the massification of microsystems within a shorter tooling development cycle time. However, the microinjection moulding process itself has mechanical and thermal demands that must be addressed and require specific consideration of the selection of the tool material. This constrains the selection of the best-suited additive manufacturing process. The current state of the art of additive manufacturing technologies at the micrometric scale favours laser sources to process layer by layer the media contained in a vat. The media type, the laser power and the laser spot size are parameters that can influence the replication tool tolerances and physical properties. This work explores the possibilities of two additive technology tooling approaches for microinjection moulding, using different materials. The research parameters included replication detailing onto the plastic part, surface roughness, microtool integrity and wear. The evaluation of these parameters was carried out using both optical and hybrid microscopy, a laser perthometer as a non-contact solution for surface roughness evaluation, scanning electron microscopy and X-ray spec-troscopy. The results of this research work showed that the processed material and technology play an important role both on surface quality and tool life, enabling criteria definition for technology selection.
- Optimisation of Shrinkage and Strength on Thick Plate Part Using Recycled LDPE MaterialsPublication . Roslan, Norshahira; Rahim, Shayfull Zamree Abd; Abdellah, Abdellah El-hadj; Abdullah, Mohd Mustafa Al Bakri; Błoch, Katarzyna; Pietrusiewicz, Paweł; Nabiałek, Marcin; Szmidla, Janusz; Kwiatkowski, Dariusz; Vasco, Joel Oliveira Correia; Saad, Mohd Nasir Mat; Ghazali, Mohd FathullahAchieving good quality of products from plastic injection moulding processes is very challenging, since the process comprises many affecting parameters. Common defects such as warpage are hard to avoid, and the defective parts will eventually go to waste, leading to unnecessary costs to the manufacturer. The use of recycled material from postindustrial waste has been studied by a few researchers. However, the application of an optimisation method by which to optimise processing parameters to mould parts using recycled materials remains lacking. In this study, Response Surface Methodology (RSM) and Particle Swarm Optimisation (PSO) methods were conducted on thick plate parts moulded using virgin and recycled low-density polyethylene (LDPE) materials (100:0, 70:30, 60:40 and 50:50; virgin to recycle material ratios) to find the optimal input parameters for each of the material ratios. Shrinkage in the x and y directions increased in correlation with the recycled ratio, compared to virgin material. Meanwhile, the tensile strength of the thick plate part continued to decrease when the recycled ratio increased. R30 (70:30) had the optimum shrinkage in the x direction with respect to R0 (100:0) material where the shrinkage increased by 24.49% (RSM) and 33.20% (PSO). On the other hand, the shrinkage in the y direction for R30 material increased by 4.48% (RSM) and decreased by 2.67% (PSO), while the tensile strength of R30 (70:30) material decreased by 0.51% (RSM) and 2.68% (PSO) as compared to R0 (100:0) material. Validation tests indicated that the optimal setting of processing parameter suggested by PSO and RSM for R0 (100:0), R30 (70:30), R40 (60:40) and R50 (50:50) was less than 10%.
- Polymer flow dynamics in microimpressions: An experimental approachPublication . Zhiltsova, T.V.; Oliveira, M.S.A.; Ferreira, J.A.; J C Vasco; Pouzada, A.S.; Pontes, A.J.The melt flow dynamics of acrylonitrile-butadiene-styrene (ABS) and polypropylene (PP) in a variable thickness microimpression was assessed by monitoring cavity temperature and pressure as relevant process parameters. A micromoulding block with a variable thickness cavity was designed, manufactured and instrumented with pressure and temperature sensors, acting as monitoring devices as well as flow position markers during filling. A full factorial design of experiment (DOE) was carried to optimize the filling of the microimpression. This study with ABS and PP suggests that mould temperature is the more important parameter for the entire micromoulding thickness range under analysis. Nevertheless, the influence of the melt temperature and the injection speed were found to depend on the micromoulding thickness and the polymer type.
- Binder system for fused deposition of metalsPublication . Cruz, N.; Santos, L.; Vasco, Joel; Barreiros, F. M.Fused Deposition of Metals (FDMe) is a technique developed to produce metallic components, based on the extrusion of metal/binder filaments to form layer by layer three dimensional objects. Filament materials must contain a high content of metallic powder to prevent shrinkage on thermal treatments like debinding and sintering, without compromising adequate rheological properties during the extrusion process. This research aims developing an FDMe system using metal/binder feedstocks in pellet/granule instead of filaments. The present work is focused on establishing a suitable binder system for fused deposition of carbonyl iron feedstocks. Binder systems based on Polyethylene Wax (PEW) or Paraffin Wax (PW), Polyethylene Glycol (PEG) and Polypropylene (PP) were investigated concerning their thermal and rheological properties. The rheological data showed that the binder systems containing PW presents lower viscosity than those having PEW. Thus, a binder system based on the former component was selected to assure appropriate rheological properties of carbonyl iron feedstocks with high content of solids for FDMe.
- Design of Pyrolysis System to Convert Waste Plastic to FuelsPublication . Oliveira, Nelson S.; Pardo, Michael; Capela, Carlos; Gaspar, Marcelo; Vasco, Joel; Heleno, LizeteThe conventional recycling technology to process waste plastic, mechanical recycling, is not suitable to recycle waste thermoplastic with high content of contamination. Pyrolysis is a promising technology since it can convert into valuable products, such as fuels and monomers. This study focused on the design of the pyrolysis equipment for waste plastic based on polyolefins. The feeder of waste plastic is a worm screw conveyor that will be in a pre-heating system. The batch reactor has support for catalyzer and can operate between 300 up to 600 ºC with attached induction system for heating. The output flows into condenser in series to separate two liquid phases and gases, depending on its boiling point. The 3D model was done with SolidWorks, control system modelled in CADe SIMU and particle simulation with FloXpress.
- Layer Thickness Evaluation Between Medical Imaging and Additive ManufacturingPublication . Almeida, Henrique A.; Vasco, Joel; Correia, Mário Simões; Ruben, Rui; Ruben, RuiAdditive manufacturing (AM) applied to the orthopaedic and surgical domains provided access to newer solutions for customised implants, customised scaffolds or even organ printing. These solutions are based on imagological data, gathered from CT-scans and/or MRI-scans. The compromise between patient’s radiation exposition and resolution along the focus direction plays an important role for the successful production of biological products. Scan detail can be increased with a thinner scanning thickness to obtain the required biological features for replication. On the other hand, a thinner scan thickness requires more scanning slices and therefore, higher exposition time to radiation. Literature shows that a maximum amount of radiation is admissible for humans, requiring an optimized approach concerning the acquisition of internal details of the human body tissues. State-of-the-art scans offer focus resolution in the range of 100 to 200 µm, although such resolution is not used for the patient’s protection. In fact, in clinical practice distance between slices are in the range of 1 to 6 mm. Concerning the AM processes that are able to use biocompatible materials, different layer thicknesses are available upon the final application in spite of the digital layer thickness that was applied during the medical imaging exam. The layer thickness during production also details the mechanical properties of the implant, with an additional aspect that the geometric data is based on information of a different layer thickness. This study intends to discuss the layer thickness used in medical imaging, the layer thickness used in AM systems providing public awareness of the operating gap between medical imaging systems and AM systems. A brief description of the accumulated errors is also presented.