Characteristics of Aluminium Effluent
Aluminium is reactive metal and is hard to extract from its ore ( Aluminium oxide Al 2 O 3 ). Studies show that the soluble form of aluminium causes harmful effects in working environment where it can be found, such as mines and factories (Abbate et al., 2003). In the environment aluminium accumulates in plant and causes health problem for animals that consumes the plants. The concentration of aluminium appears to be highest in acidified rivers at which the number of fish and amphibians are in decline due to reaction of effluent with proteins in the gills of fish, the embryos of frogs and birds (Adakole 2000). High concentrations of effluent may also be found in acidified soil which can damage the roots of trees. Pollutants from aluminiumextrusion can be divided into three categories effluent to water, emission to air, and solid waste
In Nigalex AluminiumExtrusion Company, the Aluminium extrusions are man- ufactured by extruding or forcing heated aluminium billets at about 500˚C through a steel die. The emerged extruded section is then cooled and sized to desired length. The inherent mechanical properties of materials are then optimised using heat treat- ment. Design time, improve tolerance, and close accurate control is achieved by computer aided design. For protection and improved finish appearances, natural silver or colour anodized film, plus range of colours in polyester powder coating are used. Al-Mg-Si alloys of 6060, 6063 and 6082 gives the best combination of me- dium strength (190 - 310 MPa), good surface finish and corrosion resistance, with excellent anodising properties.
Isothermal extrusion is a process of maintaining a con- stant temperature during the extrusion process inside the deformation zone. Achieving this condition is very im- portant for the production of uniform, high-quality prod- ucts. Isothermal conditions can be achieved mechanically by adjusting the speed of the ram, initial temperature of billets and die and by carefully designing the die for each product. Based on these considerations the optimization constraint to achieve isothermal extrusion can be written as follows.
Aluminium alloy, AA6061 is one of the most used high-strength material for automotive structural components. The process of hot extrusion is a promising approach for the direct recycling of aluminium machining chips. The low productivity can however be improved through optimizing the metallurgical conditions of the alloy by applying a homogenization treatment prior to extrusion (Li et al. 2004). Understanding the state of stress, strain and the temperature of an aluminium alloy going through a die during extrusion is of great importance for running the aluminiumextrusion process, because they are closely related to the surface quality of the extruded products, throughput and scrap rate. There are certain influences of the characteristic factors in the extrusion process. On the other hand, both the state of stress and the temperature are complicatedly related to the extrusion conditions, including initial billet temperature, ram speed, reduction ratio, friction at the interfaces, deformation resistance of the billet material, die geometry, as well as thermal characteristics of the billet material and the tooling (Chanda et al. 2000). In the present work, attempts were made to explore the possibilities of using the updated Deform 3D software by a Lagrangian approach to simulate the aluminiumextrusion process in the steady state. The simulation model will be prepared and analyzed by FEM tool DEFORM-3D version 11. It was aimed at the prediction on parameter process hot extrusion of 6061 Aluminium Alloy chip by using Deform 3D simulation.
The application of appropriate lubricants to die and work piece will minimize these effects, thereby producing a product with good surface finish. Lubrication plays an important role in cold extrusion since efficient lubrication prevents direct metallic contact, with the reduction of extrusion loads and wear, and the improvement of products quality and tools life (Caminaga et al, 2006). Lubricants are vital in aluminiumextrusion as they do not only improve the surface finish of the product but could also act as a heat insulant between the billet and the die (Obi and Oyinlola, 1995), both effects tending to lengthen die life. Thus, a good lubrication is necessary to reduce detrimental effect of the high temperature and pressure on the die life as well as on other components.
The following methods have been developed at the level of the GCode standardised protocol, which is sent to the 3D Printer in real time. Object geometries were defined algorithmically, de- scribing simple generalised shapes on which to study textures and aesthetics. The 3D printer receives spatial coordinates, movement speed and extrusion rate information in a command string such as ‘G0 X10.5 Y-20.7 Z0.30 E2.33 F2000’. These methods utilised the line number error checking available in firmware to ensure commands were received by the 3D printer.
The first step was a screening experiment carried out to determine the factors that have a significant effect on the response variable. This was done in order to conserve resources and to weed out insignificant factors so that further analysis could be carried out only on the significant factors. For this screening experiment, all eight controllable parameters in the nScrypt micro-extrusion process were taken into consideration. Minitab was used to investigate possible design options for a two level eight factor experiment. Both 2 8-3 and 2 8-4 designs have a resolution of IV, which means all the main effects are only confounded with three-way interactions effects or higher. To use the least amount of resources without sacrificing the amount of information gathered from the experiments, a two level fractional factorial 2 8-4 experiment was selected. Randomization of runs would cause the pressure value to shift between its high and low levels repeatedly throughout the experiment. It has been observed that repeated cycling between low and high air pressure settings causes the formation of air pockets inside the syringe and valve body. This in turn causes non-uniform and interrupted printing. In order to incorporate randomization into the experiment, the entire system would have to be flushed and cleaned after each run, which would take an inordinate amount of time and would require excessive use of cleaning supplies leading to waste of experimental paste materials. Also, two distinct pastes were to be printed, which meant a changeover would also require a system clean up. In the interest of time and resources, the experiment was therefore not randomized. A four replicate experiment was designed to account for some of the random variability in the response variable and these replicates were printed in a single setup without changeovers.
Tibbetts and Ting-Yung  proposed a mathematical model based on the physical phenomena of the extrusion process.The model was based on axisymmetric extrusion, from circular billet to round rods. The model contained the following equations and functions: project temperature state, ram position, ram speed, heat conduction, boundary heat loss, advection, heat generation, extrudate temperature, extrusion load, maximum strain rate. In this model, the boundary heat loss terms and the heat generation terms could not be given by the assumptions. The boundary heat loss terms could be formed by three gradient functions: the container wall, the die face, and the dummy pad. The heat generation terms are also composed of three functions: deformation, friction, and shearing sources. Therefore, the model had coefficients cf and ch, where cf represents the magnitude of the boundary conditions and ch represents the scaling of the flow stress about deformation, friction and shearing source. They assumed the flow stress kept a constant. The cf and ch could be identified by process data. They used this model to develop parameter identification and open-loop control methods. They also proved that parametric and control variables enter the model equations, making open-loop optimization problems and identification convenient to deal with. An example of factory test data was provided. They chose a specific objective function for the open-loop design.
The solid dispersion approach to reduce particle size and therefore increase the dissolution rate and absorption of drugs was first recognised in 1961, by the melting (fusion) method, solvent method, or fusion solvent-method. Novel techniques include rapid precipitation by freeze drying, usage of supercritical fluids, spray drying and melt extrusion. The most commonly used hydrophilic carriers for solid dispersions include polyvinylpyrrolidone, polyethylene glycols, Plasdone-S630. Many a time surfactants may also be used in the formation of solid dispersion. Hot Melt Extrusion (HME): Melt extrusion was used as a manufacturing tool in the pharmaceutical industry as early as 1971. It has been reported that melt extrusion of miscible components results in amorphous solid solution formation, whereas extrusion of an immiscible component leads to amorphous drug dispersed in crystalline excipient. The process has been useful in the preparation of solid dispersions in a single step 2 . HME is an efficient technique for producing solid molecular dispersions with considerable advantages over solvent based process. HME can be broadly defined as the process of embedding drug in polymeric carrier under controlled conditions of temperature, shear, & pressure to generate wide variety of finished products. Extrusion involves conversion of raw materials in to products of uniform shape & density by forcing through a die under controlled conditions. HME differs from simple extrusion in that, polymer, drug and excipient blends are mixed thoroughly in the molten state in this process, needing no solvents for granulation. The molten polymer serves as the thermal binder. Simple extrusion process uses aqueous or organic solvents for wetting the powder blend for granulation 12 . It is a time consuming process since drying step is critical. Use of solvents in this process may degrade the drug and residual solvents may be present after drying.
In J.Z. Gronostajski et al Discuses in their research on Direct recycling of aluminium chips into extruded products method of direct convertion of aluminium and its alloys chips into final products. The chips were comminuted in cutting device, and for the future processing the granulated chips larger than 5 mm in length were eliminated. Such prepared chips were pre-pressed with the pressure of 210 MPa and hot extruded for final products. High density and good properties of products can be obtained at high extrusion temperature 1 extrusion rates which give the time for diffusional transport of matter. In Raviraj Shetty, et al in their research on Experimental and Analytical Study on Chip Formation Mechanism in Machining of Dracs study experimental work and finite element analysis to investigate the mechanism of chip formation during machining of DRACs. Focus on understanding the influence of different cutting parameters on mechanism of machining. Chips generated experimentally and by finite element modeling during orthogonal machining of DRACs were used for this purpose In J.Z. Gronostajsk in their research describes the experience obtained with the chips of Al and its alloy with addition of small amount of tungsten powder directly converted into the final product by hot extrusion process. The mechanical and physical properties of Al and AlCu4 based composites are presented. The effect of tungsten contents and heat treatment on the properties is described. Direct conversion method do not harmfully affect an environment and produced material can be used as a final product or can be further processed by another plastic working methods like forging or rolling. Over the last two decades, aluminum recycling has grown rapidly in terms of both size and importance to the U.S. economy. Between 1950 and 1974, recycled aluminum constituted only about 5% of the total domestic aluminum market. Since then, both the fraction
Molten metal is fed into a converging cavity set by two internally cooled, counter-rotating rolls. The process relies on the heat transfer between the solidifying (& compressed) melt and the roll surfaces to solidify the aluminium which results in very high cooling rates. Because of this, conventional twin roll casters have a limited alloy/ product range - short freezing range alloys for fin, foil & building sheet.
Another aim of the paper was to verify whether Lame’s theory can accurately determine the elastic deformation of the extrusion dies. The results for the radial displacement of the inner die wall obtained by FEM and analytically by substituting the experimental values for the radial stress in Lame’s formula differ significantly. This can be explained by the failure of Lame’s equation to take into account different parameters such as variable die geometry and material hardness effect. Hence, it can be concluded that this solution is best applied in cases where the die has a simple geometry (uniform inner section profile) and uniform distribution of radial stress along the die wall, while for dies having complex shapes a more accurate theoretical model or different techniques like FEM are needed. Loss of tolerance due to the die elastic deformation may reach IT11 grade.
They combine the unique Aztec fluid handling system with the latest electronics platform, featuring Windows menu-driven software, to create a range of analyzers simple-to-operate and maintain; capable of measuring up to three sample streams. The Aztec 600 Aluminium analyzer has been designed specifically for the measurement of aluminium in potable water applications. It offers reliable, and accurate, on-line analysis of aluminium up to 2 ppm.
Because of the high temperatures involved, the thermal CVD methods are not usable for aluminium. But the chemical reactions can also be activated by a discharge method instead of the high temperature. By this method the temperature can be lowered to 100-800°C which will be acceptable for some aluminium types. These so called plasma CVD processes are not yet fully developed for tribological purposes, but a lot of effort is given by research
Auto-spermatophore extrusion Spermatophore extrusion normally occurs when cavity hairs in the epiphallus are stimulated with the copulatory papilla of the female during genital coupling (Sakai et al., 1991). It can occur, however, in different ways without genital coupling: pseudo-copulation, abortion and self-cycle renewal (Beck, 1974; Sakai et al., 1991). The spermatophore is also ejected in association with grooming when the genitalia are soiled or injured (Sakai et al., 1991). Recently, we encountered another type of spermatophore extrusion, named auto- spermatophore extrusion. This occurs following spermatophore preparation, without any prior courtship, in males that had been treated by cooling the thorax and/or abdomen (Ureshi and Sakai, 2001). Initially, auto- spermatophore extrusion was thought to be an artificially produced abnormal behaviour. However, we found that intact males paired with a female naturally exhibited auto- spermatophore extrusion with the SPaSE comparable to their own RS2 measured by the calling song. This fact reveals that auto- spermatophore extrusion is not totally an artificially produced phenomenon. It is, rather, one of the various types of spermatophore extrusion without genital coupling. Functionally, auto-spermatophore extrusion might serve to cancel the ongoing reproductive schedule when the male’s physical condition is not sufficient for reproduction. Thus, it would safely prevent the male from performing energy-consuming stridulation when the spermatophore matures.
Resin manufacturers go to extreme measures to produce a reproducible, high- quality, and useful polymer that is ready for final conversion to a product. Every time these polymers are passed through an extruder, however, the polymer has the potential to degrade, changing the chemical and physical properties of the resin. Degradation processes can often be the cause of extrusion problems. Chapter 2 begins with an introduction to how polymers are produced from the perspective of the type of chemical bonds that are important in different polymer families. It is beyond the scope of this book to discuss polymer production processes in detail. The discussion of polymerization is intended to aid the reader with a basic under- standing on how the polymer is formed from its monomer. Knowing how the poly- mer was produced from its monomers will provide the engineer with the knowledge of how the extrusion process interacts with the polymer. This basic understanding will help in troubleshooting situations where the problem is the effect of the extru- sion process on the stability of the polymer being extruded.
The temperature control in plastic extrusion machine is an important factor to produce high quality products. The extrusion consists of large barrel divided into three temperature zones namely barrel, adapter and die zone respectively. The temperature zone uses more number of heaters in order to provide different temperature ranges. In the temperature response control rapid temperature rise and precise stable value instable state mode is required. The temperature system has non linearity, long delay time, and large time constant and undetermined system. Under poor thermal conditions, several Processing problems can occur, e.g. thermal degradation, output surging, poor mechanical properties, dimensional instability, poor surface finish and poor optical clarity . Die melt temperature homogeneity depends on the selection of processing conditions, machine geometry and materials properties.The quality of extrudates depends on uniform temperature distribution, physical property of raw material, and so forth. High efficient plastic extrudates can be obtained only when temperature in all the zones is precisely controlled. The temperature section of PVC extrusion Plant is shown in Figure 3.