Papers by Keyword: Mould

Abstract: 3D printing has been recognized to be such a game-changer in manufacturing that it has now permeated virtually every aspect of the industry, including mould and die casting. A thorough examination of 3D printing's past, present and future in the business is provided here. Casting procedures may be enhanced or drastically altered by 3D printing. The design of goods, assemblies, and parts will be transformed by 3D printing, which is more than just a manufacturing technology. With the aid of 3D printing, sand casting is a technique that can make complex components out of almost any metal alloy at a reasonable cost. Using this integration, producers may build massive components in the least amount of time. It has also established a distinctive place in other casting elements; Examples include the ceramic shell, sand mould sand core, and wax pattern, we'll learn more about sand casting and 3D printing this week.

Abstract: The investment casting into a ceramic shell of magnesium alloys brings several difficulties, one of which is the high reactivity of some magnesium alloys with the often-used ceramic shells. In the group of these potentially problematic alloys belong the AZ91 magnesium alloy too. This paper aims to describe the interaction of magnesium melt with ceramic shell, especially from the point of view of manufacturing problems on the surface of emerging defects with reduced corrosion resistance. Samples of AZ91 magnesium alloy castings in as-cast and heat-treated were microstructurally evaluated. Surface defects were analysed using light and scanning electron microscopy, including their EDX chemical microanalysis.

Abstract: Price and time are two major concerns in the industry which encourages the development and manufacturing of new dies for sheet metal forming applications. Additive manufacturing (AM) and rapid tooling (RT) are now emerging techniques for producing cost-effective and fast production of sheet metal forming dies with excellent mechanical and wear resistance properties. The paper gives an insight into AM processes that were implemented in the tooling industry to enhance moulding efficiency and sheet metal forming processes. The advantages and challenges observed in using AM are highlighted and discussed as opposed to traditional tooling. The RT processes used in moulding and sheet metal formation are addressed, and their limitations are highlighted. The paper also discusses several possible application areas in which AM technologies can be used further to enhance the efficiency of the devices. Finally, discussion on current issues related to the use of AM in tooling has been presented.

Abstract: Microbial growth often thrives in humid conditions, at high relative humidity. Moulds are complex organisms; many types of mould are able to survive strong variations in humidity and temperature, such as those on building façades. For some building materials a critical relative humidity is determined, which functions as a theoretical threshold; at this (or lower) relative humidity microbial growth will likely not occur. Hemp-lime is a building material that consists of hemp shiv (the woody core parts of the hemp stem) and building lime. It is a material that can be used for walls, and even though it has been used for more than 20 years, thusfar little is known about its critical moisture levels for microbial growth. The aim of this research was therefore to determine at what relative humidity microbial growth occurs on carbonated hemp-lime material, and to study if there is a protective influence of a carbonated lime binder on the hemp shiv. The objective was to study microbial growth on hemp shiv, hemp-lime and on hemp with a thin layer of lime at three relative humidity (75 %, 85 % and 95 %) and at two different temperatures (15°C and 23°C); conditions that could occur naturally in a hemp-lime façade exposed to high rain loads in a northern European climate. Hemp shiv seems to have a relatively low resistance to microbial growth, similar to that of wood. However, because the hemp is protected by lime it can withstand much higher relative humidity without microbial growth occurring on the material. The critical moisture level for hemp-lime seemed to occur between 75 and 85 % RH, while the material was completely without microbial growth at 75 % RH. The lime had a protective effect on the hemp and acted as a mould inhibitor, both over time and with varying temperature and humidity.

Abstract: Laser cladding technology is widely used in the surface modification of parts due to its excellent properties such as high hardness, high wear resistance and corrosion resistance. Extends the life of these parts under normal use conditions, greatly reducing production costs. In this paper, the influence of different parameters such as laser cladding process parameters—laser power and scanning speed, and their interaction on the performance of mold cladding layer is discussed, and the future development direction of laser cladding technology in mold is prospected.

Abstract: The purpose of this paper is to present the influence of the casting parameters in the process of producing aluminium alloy components of gearbox housing type in automotive industry. The project has as objectives the minimization of the most common casting defects met in casting of gearbox housings through adjusting the parameters of the process. In order to minimize these defects, it was studied the casting speeds in phases I and II, multiplication pressure of phase III and the mould temperature that is influenced by both the cooling channels inside the mould and the spraying process of the mould (lubrication/cooling) that helps regulate the optimum temperature. The experimental results showed that the casting defects such as pores, cast in stages, shrinkage cavities, gas holes and tightness are significantly reduced by periodically controlling and correcting the specific casting parameters.

Abstract: Mould risk is an increasing problem in current housing branch. Mould is considered to be one of the most important features of Sick Building Syndrome. In most cases it is caused by the increased moisture of building barriers and improper humidity of indoor air. In old buildings it is caused by improper raising techniques, lack of isolation against moisture and insufficient building materials applied for construction. Modern housing also suffers problem of mould risk which is connected to introducing of the new materials and technologies for external envelopes of the buildings. These often increase the tightness of the buildings and cause improper performance of natural ventilation systems, which makes suitable conditions for mould to grow.In the paper there is proposed an attempt to evaluate mould risk in the buildings using e-nose, being a gas sensors array which consists of eight metal oxide semiconductor (MOS) gas sensors. This device is commonly applied for air quality assessment in environmental research. First part of the article is a description of e-nose technology and its possible applications in constructions. The second part shows the exemplary e-nose readouts of indoor air sampled in clean reference rooms and threatened with mould development. Obtained multivariate data are processed and visualized using a Principal Component Analysis (PCA).

Abstract: In the fast moving technological world, few researchers are trying to formulate systems with automatic mould design processes in order to reduce mould design and development time and produce a consistent mould's quality. Currently, no commercial software are able to generate core and cavity without user intervention during the process. Thus, an algorithm is proposed in this research to automatically generate core and cavity of moulds by using slicing and Boolean-based approach. A 3D moulded part in a standard CAD file format is used as an input for the algorithm and the output is presented as a set of core and cavity in 3D model. Two criteria to define the best generated core and cavity are considered at this stage which is undercut and floating lump.

Abstract: Currently it is under pressure to reduce the energy consumption of the buildings. The pressure is noticeably reflected in the current way of building designing, in general. Therefore, essential part of these objects become air-conditioning (ventilation) systems, mainly due to possibilities of heat recovery and controlled ventilation. This contribution focuses on ventilation systems, low energy houses, which aims to highlight the issue of purity of these systems on the microbial level. Evaluate the impact of external and internal environment following the condition of HVAC systems in time, in the real objects. The purpose (aim) of this all is to remind that there are other aspects that have to be considered in the design and subsequently, in the use of the systems, such as the impact of the nature of the building use on the purity of air-conditioning systems. It is necessary to point out that the presented ventilation systems have a significant impact on the creation of the internal environment, and equally they can harm, instead to be beneficial.

Abstract: Not only in Austria but also in EU and worldwide is the problem concerning restoration of old buildings very present. In the soaked massive brick walls are very often, moist caused, low thermal resistance and very low surface temperature, especially in the walls corner. At the Research Centre of Building Physics, TU Vienna, was an investigation carried out, which should act solution to this problem. To compensate thermal deficits of a cold wall corner (thermal bridge) area a linear heating component has been studied in the form of a pipe-in-pipe system, which raises the temperature of the wall corner and prevents the condensation. Through a targeted local heat supply, the necessary heating power is registered, within the temperature doesn’t fall below the critical value, at which it can come to building of condense water or to formation of mould. The calculations performed with a COMSOL program were carried out using tests on a real object. Thus, the calculated and the measured values could be compared. The first results can be seen as promising in terms of heating power saving, where you don’t need to heat the whole room to a high temperature. Through the selective heat power supply in the corner area thermal bridge effect will be eliminated.