Joel Oliveira Correia Vasco

Bio: Joel Oliveira Correia Vasco is an academic researcher from Polytechnic Institute of Leiria. The author has contributed to research in topics: Melt flow index & Injection moulding. The author has an hindex of 5, co-authored 22 publications receiving 198 citations. Previous affiliations of Joel Oliveira Correia Vasco include University of Minho.

Additive manufacturing tooling for the automotive industry

Abstract: Automotive industry faces new challenges every day, new design trends and technological deployments from research push companies to develop new models and facelifts in short term, requiring new tools or tool reshaping. Concerning the current world economic scenario, decreasing time for tooling up becomes as important as decreasing time-to-market. Such scenario opens up the horizons for new manufacturing approaches like additive manufacturing, in this case, applied for tooling up a stamping process on the automotive industry for the production of body panels. This approach enables the manufacturing of stamping inserts using similar high performance alloy steel as in conventional tooling, therefore, without losing tool mechanical properties. The stamping tools produced were tested by an automotive company in order to determine tool behaviour under real operating conditions, considering the high level demands of the stamping process. The results obtained enabled to conclude that metal additive manufacturing provided tools for the stamping process with excellent performance with a significant decrease on time-to-tooling.

History of Additive Manufacturing

Abstract: COPYRIGHT © 2016 1 WOHLERS ASSOCIATES, INC. History of additive manufacturing by Terry Wohlers and Tim Gornet This 38-page document is a part of Wohlers Report 2016 and was created for its readers. The document chronicles the history of additive manufacturing (AM) and 3D printing, beginning with the initial commercialization of stereolithography in 1987 to April 2015. Developments from April 2015 through March 2016 are available in the complete version of the report. An analysis of AM, from the earliest inventions in the 1960s to the 1990s, is included in the final several pages of this document. The commercial use of AM first emerged in 1987 with stereolithography (SL) from 3D Systems, a process that solidifies thin layers of ultraviolet (UV) light-sensitive liquid polymer using a laser. The SLA-1, as a beta test system, was the first commercially available AM machine in the world and was the precursor of the once popular SLA 250 machine. (SLA stands for StereoLithography Apparatus.) The Viper SLA product from 3D Systems replaced the SLA 250 many years ago. In 1988, 3D Systems and Ciba-Geigy partnered in SL materials development and commercialized the first-generation acrylate resins. DuPont’s Somos stereolithography machine and materials were developed the same year. Loctite also entered the SL resin business in the late 1980s, but remained in the industry only until 1993. After 3D Systems commercialized SL in the U.S., Japan’s NTT Data CMET and Sony/D-MEC commercialized versions of stereolithography in 1988 and 1989, respectively. NTT Data CMET (now a part of Teijin Seiki, a subsidiary of Nabtesco) called its system Solid Object Ultraviolet Plotter (SOUP), while Sony/D-MEC (now D-MEC) called its product Solid Creation System (SCS). Sony stopped manufacturing SL systems for D-MEC in 2007. In 1988, Asahi Denka Kogyo introduced the first epoxy resin for the CMET SL machine. The following year, Japan Synthetic Rubber (now JSR Corp.) and DSM Desotech began to offer resins for the Sony/D-MEC machines. In 1990, Electro Optical Systems (EOS) of Germany sold its first Stereos stereolithography system. The same year, Quadrax introduced the Mark 1000 SL system, which used visible light resin. The following year, Imperial Chemical Industries introduced a visible light resin product for use with the Mark 1000. ICI stopped selling its resin about one year later when Quadrax dissolved due to a legal conflict with 3D Systems.

Additive manufacturing for the automotive industry

Abstract: The automotive industry is one of the most competitive industries worldwide. New market and design trends emerge continuously, requiring new manufacturing approaches to comply with the automotive industry. Additive manufacturing (AM) provides an important competitive edge to this industrial domain, acting as a disruptive approach by shortening products design and development, delivering flexibility on production, and producing optimized automotive components and customized vehicle products upon request. Automotive production benefits from the use of AM on soft assembly tools or specialized tools to produce vehicle components. The freeform capacity offered by AM enables the design and direct production of optimized automotive components, focused on vehicles performance as well as customized assembly tools to enhance productivity. Another related AM technical advantage is the possibility of producing lightweight components, supported by generative design algorithms. Last but not least, the time-to-market on AM parts decreased significantly, enabling the concept of mass customization. The strong trend on energy consumption decrease poses new challenges regarding vehicles design, performance, and regulations compliance. AM is the key-enabling technology for new vehicles considering the actual paradigm shift from the common combustion engine to alternate motion systems. This chapter presents an overview on AM applications on the automotive industry, focused on the technical and economic impact provided by this manufacturing technology.

Laser micromachining for mould manufacturing: I. The influence of operating parameters

Abstract: Purpose – Laser milling is a recent process in mould making, providing several advantages over traditional mould making technologies by reducing manufacturing time, shortening the number of machining operations and avoiding expensive electrodes. This paper investigates the influence of the operating conditions on both the surface quality and material removal for two types of materials commonly used in mould making.Design/methodology/approach – Laser scanning strategies and operating parameters like scanning speed and laser frequency and power were tested, regarding surface quality and material removal rate. The most representative parameter of the real surface quality, Rk, the core roughness parameter, is used to characterise the surface finishing on all cavities.Findings – The findings of this research work suggest that it is possible to significantly reduce processing time by increasing the hatch spacing up to a value close to the laser beam spot diameter, without compromising surface quality. Lower pul...

Thermo-rheological behaviour of polymer melts in microinjection moulding

Abstract: 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.

FDM-Based 3D Printing of Polymer and Associated Composite: A Review on Mechanical Properties, Defects and Treatments.

Abstract: Fused deposition modelling (FDM) is one of the fastest-growing additive manufacturing methods used in printing fibre-reinforced composites (FRC). The performances of the resulting printed parts are limited compared to those by other manufacturing methods due to their inherent defects. Hence, the effort to develop treatment methods to overcome these drawbacks has accelerated during the past few years. The main focus of this study is to review the impact of those defects on the mechanical performance of FRC and therefore to discuss the available treatment methods to eliminate or minimize them in order to enhance the functional properties of the printed parts. As FRC is a combination of polymer matrix material and continuous or short reinforcing fibres, this review will thoroughly discuss both thermoplastic polymers and FRCs printed via FDM technology, including the effect of printing parameters such as layer thickness, infill pattern, raster angle and fibre orientation. The most common defects on printed parts, in particular, the void formation, surface roughness and poor bonding between fibre and matrix, are explored. An inclusive discussion on the effectiveness of chemical, laser, heat and ultrasound treatments to minimize these drawbacks is provided by this review.

Rapid Prototyping for Soft‐Matter Electronics

Abstract: A series of rapid and inexpensive methods to produce elastically soft sensors and circuits in minutes using a CO2 laser (10.6 μm wavelength) are introduced. These soft-matter electronics are composed of laser-patterned films of conductive poly(dimethylsiloxane) (cPDMS) and liquid-phase gallium–indium (GaIn) alloy embedded in a thin sheet of soft silicone elastomer. Direct laser patterning eliminates the need for photolithography, replica molding, and customized inkjet or microcontact (μCP) printing, and allows conductive traces of cPDMS and liquid GaIn to be rapidly integrated into a single soft-matter circuit. The versatility of this fabrication method is demonstrated by the production of a variety of electrically functional soft-matter sensors and circuit elements that contain features with >150 μm planar dimensions. It is postulate that in the case of GaIn alloy patterning occurs when the recoil force of the escaping vapor exceeds the liquid's surface tension. This mechanism exploits the unique “moldability” of liquid GaIn alloy, which forms a surface oxide of Ga2O3 that allows the patterned film to maintain its shape.

In-Plane Deformation Mechanics for Highly Stretchable Electronics.

Abstract: Scissoring in thick bars suppresses buckling behavior in serpentine traces that have thicknesses greater than their widths, as detailed in a systematic set of analytical and experimental studies. Scissoring in thick copper traces enables elastic stretchability as large as ≈350%, corresponding to a sixfold improvement over previously reported values for thin geometries (≈60%).