Extrusion Industry Research Articles

Polymeric field synergy principle: Revealing the intrinsic mechanism of screw channel optimization to enhance thermal management and process efficiency

The process efficiency and energy efficiency of extrusion equipment emerge as pivotal challenges constraining the development of the polymer extrusion industry. This article presents a new principle of polymeric field synergy to guide the solution to the low mixing efficiency and energy utilization efficiency of traditional extrusion equipment. Finite element analysis was conducted on four novel unconventional screw configurations and compared with the traditional single-thread screw. Results revealed that more complicated melt flow patterns generated in the modified novel screw configurations enhanced the stretching deformation or helical flow. The stretching or helical flows to varying degrees during the melt extrusion process thereby improved the mixing and heat transport efficiency. Among them, helical flow induced by the Maddock element exhibited the most significant impact on stretching flow and ductile deformation in the flow field. Simultaneously, the helical flow caused radial motion of the internal material, significantly promoting the synergy between the velocity field, velocity gradient field, and temperature gradient field. This enhanced radial heat and mass transport efficiency within the screw channel, subsequently improving the overall operational efficiency of the equipment. The results of the finite element analysis have substantiated the scientific validity of the polymeric field synergy principle.

Optimization of Non-Newtonian Flow through a Coat-Hanger Die Using the Adjoint Method

The use of coat-hanger dies is prevalent in the plastic film and sheet extrusion industry. The product quality and the power of the extrusion machine depend on the uniformities of the fluid velocity at the exit and the pressure drop. Die manufacturers face the challenge of producing coat-hanger dies that can extrude materials uniformly and with a minimal pressure drop. Previous studies have analyzed the die outlet’s flow homogeneity and pressure drop using various numerical simulations. However, the combination of the scheme programming language together with the Adjoint Method of Optimization has yet to be attempted. The adjoint optimization method has been demonstrated to be beneficial in addressing issues related to shape optimization problems and it may also be beneficial in optimizing the design of dies used in polymer melt extrusion. In this study, the proposed innovations involve incorporating both the Scheme programming language and Adjoint solver to examine and optimize the coat hanger’s flow homogeneity and pressure drop. Before optimization, the outlet velocity was almost 10 times higher at the die center than at the edges but after optimization, it became more uniform. The proposed optimized coat-hanger die geometry results in more uniform melt flow as demonstrated by the velocity contour plot and the outlet velocity graph in the die slit area, reducing the deviation value from 0.097 to 0.015. Additionally, the mass flux variance across the die outlet decreased by 71.6% from 0.015069 kg m−2 s−1 to 0.004281 kg m−2 s−1. Therefore, using this method reduces the amount of time wasted on trial and error or other optimization techniques that may be limited by design constraints.

Heat behavior and axial temperature distribution of a Ti-6Al-4V alloy in a superconducting induction heater with a controllable magnet structure

Ti-6Al-4V (TC4) metal billets can usually be preheated by gases, resistance furnaces, and conventional induction heater powered by alternating current. However, the disadvantages of these heating methods are long heating time and small skin depths. The novel superconducting induction heater has several advantages in terms of heating quality, heating efficiency, heating time and axial temperature control. It has gained successful commercial application in the large aluminum extrusion industry in 2021. However, no studies on TC4 heating behavior using a superconducting induction heater have been reported, and no studies on uniform and gradient temperature characteristics of TC4 in superconducting induction heater. The uniform temperature distribution of TC4 is helpful to reduce the heating residual stress of forgings. The gradient temperature distribution of TC4 billet can obtain different properties in different parts of the same TC4 billet, which is suitable for manufacturing functionally graded materials. In this study, a high-temperature superconducting (HTS) direct-current (DC) induction furnace was firstly used to perform heating experiments for TC4 metal billets of 1250 mm length and 220 mm diameter. The application of the superconducting magnet for induction heating allows for high-power and fast heating of the TC4 billet at an extremely low frequency (4 Hz). The HTS induction heater technology has the advantages of high penetration depth, high energy efficiency (>82%), high heating uniformity, and controllable temperature distribution. Additionally, it improves the metal heating quality and reduces the heating cost. The 10 identical iron pieces of superconducting magnet on both sides of the iron core can be adjusted independently. The gradient and uniform temperature distributions of the thermally optimized TC4 billets were experimentally determined using adjustable electromagnetic heating power. Subsequently, the heating behavior of TC4 billets was modeled and compared using the numerical multiphysical finite element method; the results obtained using this method are in agreement with the experimental results. An expert database has been established for the heating strategy of TC4 billets. The optimized axial temperature distribution was analyzed for three different TC4 billet diameters (Φ220, Φ300, and Φ446 mm). The obtained gradient and uniform axial temperature distributions had an error of less than ±3 °C, and the adjustable difference at two-ends temperature of TC4 billets was in the range 10–100 °C/m. Finally, the maximum thermal stress on the TC4 billet during heating also was analyzed. The results of this study will be useful of the novel HTS induction heater application for TC4 billet heating, and axial temperature control. The uniform temperature distribution control will reduce the heating residual stress of forgings. The gradient temperature distribution of TC4 billet is suitable for manufacturing functionally graded materials.

Peripheral coarse grain formation in AA2024 and AA6063 aluminium alloys- A comparative study

Multifaceted mechanical and physical characteristics such as light weighting, high strength to weight ratio, electrical conductivity, and ease of fabrication have helped aluminium alloys to find its application in aerospace and automobile sectors. The most famous aluminium alloy used in extrusion is AA 6063 because of its 100% extrudability. AA2024 is from the family of hard alloys which finds its applications in the strength requirements and major alloying additions comprise of Cu, Mg which contributes to age/precipitation hardening phenomena. Because of its inherent nature of high strength, it is challenging to extrude. Extrusion is one of the major metals forming processes which involve several process parameters such as, temperature, strain rate, ram speed and post forming heat treatment operations. To attain the specific mechanical properties, microstructure of the extrudate is of utmost importance and evolution of the same needs to be understood. Heat treatable aluminium alloys series of 2xxx, 6xxx or 7xxx are prone to peripheral coarse grain structure, which is responsible for the loss of mechanical and corrosion performance. To eliminate PCG entirely or to minimize it is the fundamental interest of extrusion industries and to come up with a workable solution, it is necessary to twig the microstructure evolution of AA6063 and AA2024 alloy during extrusion and after heat treatment. The present work is aimed at comparative study of the PCG formation of press quenched samples in AA6063 and heat-treated (T6) samples of AA2024.

Additive manufacturing for plastic extrusion die tooling: A numerical investigation

Additive Manufacturing (AM) has become commonplace to iterate concepts and realize products in different industries. The maturation of AM has made it a viable alternative to Subtractive Manufacturing (SM) processes, nevertheless there remain several unexplored opportunities. One of these is profile plastic extrusion tooling, which is typically produced at low volumes, can be complex in geometry, and could benefit from AM’s bottom-up process. Such manufacturing options raise the question of how one can evaluate whether AM should be considered as opposed to SM. The objective of this work is to establish a technology assessment method to evaluate which extrusion profile cases warrant consideration for AM. Results from Computational Fluid Dynamics (CFD) simulations of polymer flow through the flow channel are related to several applied parameters used by the extrusion industry. This provides a means to evaluate a tool’s design virtually before implementing in production. The technology assessment is performed on a U-Channel case, which is a common open profile shape with several product variations in industry. Results from this work indicate that there is no advantage of pursuing AM over an SM informed design for the specific U-Channel case used in this study. In addition, streamlining features alone do not necessarily lead to clear improvements, highlighting the need for technology assessment tools and methods to evaluate whether AM or SM should be implemented. This work lays the foundation for evaluating which extrusion profile cases warrant consideration for an AM process.

Impact of Micro Silica Filler Particle Size on Mechanical Properties of Polymeric Based Composite Material.

In this study, silica in the form of raw local natural sand was added to high-density-polyethylene (HDPE) in order to develop a composite material in the form of sheets that could have potential applications in thin film industries, such as packaging, or recycling industries, such as in 3D printing. The silica/HDPE composite sheets were developed using a melt extruder followed by using a hot press for compression molding. The impact of two different particle sizes (25 µm and 5 µm) of the silica particles on selected properties such as toughness, elastic modulus, ductility, and composite density were analyzed. A considerable increase in the toughness and elastic modulus was observed from 0 wt% to 20 wt% with a 25 µm filler size. However, a general decreasing trend was observed in the material's toughness and elastic modulus with decreasing particle size. A similar trend was observed for the ductility and the tensile strength of the sheets prepared from both filler particle sizes. In terms of the composite density, as the filler was increased from 20 wt% to 50 wt%, an increase in the composite densities was noticed for both particle sizes. Additionally, the sheets developed with 25 µm particle size had a slightly higher density than the 5 µm particle size, which is expected as the size can account for the higher weight. Results from this work aim to analyze the use of local sand as a filler material that can contribute towards maximizing the potential of such composite materials developed in extrusion industries.

Simulation of Coarse Grain Evolution during Hot Extrusion of Al-Mg-Si Alloy

Coarse grains at or near the surfaces of extruded aluminum profiles can have a major detri-mental influence on their ductility and surface quality. Thus, the extrusion industry aims to minimizecoarse grains while increasing the productivity of the process. Peripheral Coarse Grains (PCG) de-velop depending on local state variables such as temperature, strain and strain rate. Here we presenta microstructure based material model implemented into HyperXtrude™, capable of predicting thedevelopment of PCG by combining geometric Dynamic Recrystallization (gDRX) and conventionalgraingrowthmodels.Duetoitshistorydependence,themodelisimplementedtorunduringthewholetransient extrusion simulation. The first results of the predicted ram force as well as final grain distri-bution in the profile show reasonable agreement with experimental trials and electron backscattereddiffraction results.

Effect of nitriding conditions and operation temperatures on dry sliding wear properties of the aluminum extrusion die steel in the industry

Hot work tool steels are widely preferred in the hot extrusion of aluminum alloys. Nitriding of die steels in the aluminum extrusion industry is a well-accepted surface hardening method against surface wear and deformation. In this study, substrate material (DIN 1.2344 steel) is diffusion coated by salt bath nitriding method for 1 h, 2 h, and 3 h. The effect of different nitriding conditions on hardness, tensile and impact properties, wear behavior, and coefficient of friction is studied. Diffusion hardened surface is examined with different characterization techniques. The effect of nitriding time on diffusion layer thickness, tensile properties, impact energy, and wear resistance properties are investigated. It is shown that increasing nitriding time enables thicker diffusion layers that modify the adhesive's wear mechanism to abrasive. Increased nitride layer thickness resisted friction much more compared to less nitrided specimens. On the contrary of wear resistance, tensile properties are reduced due to the diffusion layer’s notch effect.

Reducing the environmental impacts of aluminum extrusion

The aluminum extrusion industry is growing rapidly; however, there has been little work on quantifying or reducing extrusion's environmental impacts. This article first derives cradle-to-gate cumulative energy demand, greenhouse gas emission, and cost models for direct aluminum extrusion using data collected from extrusion companies, life cycle inventory measurements (e.g., electricity demand) from our own case studies, and physics-based extrapolations. These models show there is significant scope for increasing both the process energy and material efficiency; however, only increasing the material efficiency will lead to significant environmental benefits and cost savings. Subsequently, an alloy-shape-application material flow analysis of the 2018 North American extrusion industry is conducted to highlight opportunities for improved material utilization throughout the supply chain. Material flow data were collated from existing academic and gray literature in addition to semi-structured interviews with North American extrusion experts. The material flow analysis reveals that around 40% of all aluminum cast into extrusion billets is scrapped before completion in a fabricated product, which increases the cost of the fabricated profile by approximately 16% and the greenhouse gas emissions and cumulative energy demand by approximately 40%. Most of this scrap is created by removing structural and surface finish extrusion defects that are inherent to the current process. Process adaptations that might reduce the material scrapped due to these defects are identified and discussed. Even a 10% reduction in extrusion process forming scrap could save the North American (U.S. and Canada) extrusion industry 270–311 million USD per year and prevent the release of 0.5–2.3 Mt.CO2eq annually.

Modification of a bituminous binder using waste products from the polymer industry

In this paper, we have investigated the possibilities of the modification of bituminous mixtures using recycled plastic. Waste from enterprises that process plastic is a serious danger to the environment, which is why the need to develop technologies for their processing is not in doubt. The economic advantages of using such additives are that the modifier used is the total waste of industrial enterprises that manufacture products from thermoplastics. Thus, it is possible to solve several problems at once: reducing the cost of production of bitumen; improvement of their physical and chemical characteristics and recycling of non-recycled waste. Patent information on the use of thermoplastics as a bitumen modifier was analyzed. During the work, waste from the extrusion industry of high-pressure polyethylene (LDPE) used. The influence of additives on the basic physical parameters of bitumen is shown. In the course of research, it was found that the addition of 2-3% polymers to the original formulation allows us to obtain bitumen, the main physical parameters of which (penetration, ductility, softening) meet the existing requirements. With this method of bitumen modification, the cost of their production is reduced without deterioration of the properties of the finished product. We also investigated the possibility of introducing up to 25% modifiers into the formulation, for maximum utilization of polymer waste. The bitumen obtained in this way can be used in regions with a hot climate. An important fact is the unification of the method of introducing additives into the existing technology, which does not require its change. The results of the study showed that thanks to the results obtained, it is possible to significantly reduce the cost of producing asphalt and bitumen products, expand the technological properties of finished road surfaces, and solve the problem of recycling plastic waste.

A Quantitative Occupational Risk Assessment Methodology Based on TOPSIS-Sort with its Application in Aluminum Extrusion Industry

The metal products industry, including the aluminum extrusion industry, is one of the sectors with high risk in terms of occupational health and safety (OHS). Considering this fact and the increasing trend of occupational accidents in the sector, the need to enhance occupational safety becomes clear. Therefore, this study proposes a quantitative occupational risk assessment by a sorting-based technique for order performance by similarity to ideal solution (TOPSIS-Sort) methodology to manage risks in the aluminum extrusion industry. The methodology has been demonstrated by evaluating 28 potential hazards under three risk parameters (probability, severity and frequency). The assessed hazards are divided into five risk clusters (Very high risk, High risk, Substantial risk, Possible risk, and Risk) and control measures that will initiate the reduction of risks have been determined. Results of the study show that while one hazard has been placed in the Very high risk cluster, 3 in the High risk cluster, 23 in the Substantial risk cluster and one in the Possible risk cluster.

Heating Characteristics of TC4 Titanium Alloy in an HTS DC Induction Heater

Titanium andits alloyscan be heated using heavy oils, gases, resistance furnaces, liquid media, and conventional alternating current (AC) induction heaters. However, the novel superconducting direct current (DC) induction heater has several advantages over its AC counterpart in terms of heating time, efficiency, and heating quality. Therefore, it has gained remarkable success in the aluminum extrusion industry. The superconducting DC induction heaters can achieve efficiency by up to 90%, which is significantly higher than the AC induction heater (40-50%). In this study, experiments on the heating of Ti-6AL-4V (TC4) billets (Φ = 220 mm × L = 1,250 mm) using a high-temperature superconductor (HTS) induction heater were performed. A numerical 3D finite element method (FEM) model was developed to analyze the heating behavior of TC4 billets. The results from the simulation and experiments show a good agreement. Further, the radial temperature profile, heating power, and heating time were studied using the developed model. The results show that the penetration of the heating power decreases with the rotation speed. Hence a low radial temperature difference was achieved by applying an exceptionally low rotational speed on the DC induction heater, 100-500 rpm (corresponding to 1.7-8.3 Hz). We also found that heating power increased rapidly with the diameter of the TC4 billet. Therefore, the heating time could be substantially minimized by increasing the magnetic flux density and rotational speed, especially for a large billet with a diameter exceeding 300 mm. The results obtained in this study will be useful for industrial applications of Ti alloy pre-heating.

An analytical approach for the design optimization of bearing land in the metal extrusion of shaped sections

Bearing region plays an important role in controlling material flow and its optimal design could lead to high quality extruded products. On the other hand, too much of bearing causes the process load to increase. Thus, there must be an optimum point where the bearing lands and the extrusion pressure are just the right values. Determining the proper bearing length is often performed using trial and error methods in the extrusion industry and numerical analysis. The aim of this study is to optimize the bearing length in forward extrusion dies using upper bound method for non-axisymmetric sections. A generalized kinematically admissible velocity field is employed to obtain uniform velocity at the exit surface of the die. Dead metal zone and bearing region define the geometry of the deformation zone. The multi-objective optimization using response surface methodology was applied to optimize the relative extrusion pressure and the deviation of the mean value for the velocity at die exit. Using this method, the proper bearing length is determined. Optimization of bearing land is performed for extrusion of rectangular and L-shaped profiles. The proposed analytical method was verified by physical modelling experiments and numerical simulations. A unique answer for the bearing design could be obtained using the suggested method in a few seconds opposing to numerical method which required many timely and costly trials. This method would be useful for die designers to get the appropriate bearing land and at the same time not to increase the process load excessively.

Innovative aluminium extrusion: increased productivity through simulation

This research has developed a new approach to increase productivity and competitiveness of the Australian aluminium extrusion industry in collaboration with Capral Ltd. The innovative approach comprised optimisation of extrusion dies design coupled with subsequent optimisation of extrusion parameters such as extrusion ratio, ram speed, lubrication using customised finite element (FE) simulation software QFORM7. To accommodate the modelling to specific alloys, the aluminium alloys used by the industrial partner were characterised and parameters of developed model derived, which results in establishment of the database of materials incorporated into the commercial FE software. Based on experiments and simulation forming limit diagrams for a range of aluminium alloys used by Capral Ltd were developed. The earlier developed model for predicting the extrusion defects based on damage accumulation was also incorporated in the commercial FE software QFORM7. This model was instrumental in assessment of die failure and optimisation of die design. The economic benefits of the developed approach and models in terms of increased productivity rate and extrusion die life was proven.

A new method for bearing design in the metal extrusion of profiled sections

Bearing design is a major issue in controlling material flow and producing high-quality extruded products. Adjusting the bearing length is often performed using costly trial and error approaches in the extrusion industry. This is true even when using finite element analysis. The purpose of this study is to optimize the bearing length of forward extrusion dies using an analytical approach for metal extruded sections. This method is based on a generalized kinematically admissible velocity field to obtain uniform velocity at the die exit. The deformation zone contains the dead metal zone (DMZ) and bearing channel which is assumed to be non-linear. Based on this assumption, a new formulation was developed to define the geometry of the deformation zone. The response surface methodology was employed to optimize the relative extrusion pressure, deviation of the mean value for the velocity at die exit, and subsequently the bearing length for the extrusion die. Using this theoretical method, extrusion of rectangular and L and T-shaped sections was investigated and compared to previous work. Physical modelling experiments and finite element simulations were carried out to validate the suggested analytical method. The proposed analytical method gave a unique answer for the required bearing design in a few seconds contrary to finite element method which required many timely and costly trials. This method would be useful for die designers to get the appropriate bearing length.

The application of FEA for optimization of die design

The use of finite element analysis (FEA) to predict material flow and die deflection is well implemented in the scientific community but it is still new in the extrusion industry or for die makers. This paper deals with the advantages and limitations of FE-analysis to predict material flow and to optimize die design from an industrial point of view. For this study two software packages, HyperXtrude® and PF-Extrude®, have been used to predict the material flow in two applications, the optimization of a heat sink profile and the filling process of a porthole die

Effect of Corporate Social Responsibility on Marketing Performance of a Nigerian Manufacturing Company

This study examined the effect of corporate social responsibility (CSR) on marketing performance (MP) of a manufacturing company-Aluminum Extrusion (ALEX) Industries PLC Nigeria. Data were generated from the company's internal and annual reports from 2009 to 2015. Using SPSS version 21, stated hypotheses were tested with linear regression analysis. The findings revealed that CSR only has a strong positive relationship with one variable of MP-Market Share. The other two variables (Financial Performance and Sales Growth) were all negatively associated with CSR. Based on these, the study concludes that the negative effect CSR has on profitability and sales growth of the company is as a result of the inconsistent practice of CSR by the company. Therefore, the study recommends among others, that firms should be consistent in the implementation of their CSR projects in other to really understand its effect on the company’s marketing performance.

Comparative Impact Of Corporate Social Responsibility On Marketing Performance: A Study Of ABC PLC And ALEX Industries PLC, Imo State Nigeria.

The broad aim of this study was to compare the Impact of Corporate Social Responsibility (CSR) on Marketing Performance of a transportation company-Associated Bus Company (ABC) PLC and that of a manufacturing firm- Aluminum Extrusion (ALEX) Industries PLC, all in Imo State. Data were generated from the two companies' internal and annual reports from 2009 to 2015. Using SPSS version 20 and 21, stated hypotheses were tested with paired sample t-test and simple linear regression. The findings revealed that a significant difference exists on the market share and sales growth of the two firms judging from their corporate social responsibility activities, while no significant difference exists on their financial performance. Again, while CSR exerts positive impact on the market share and sales growth of ABC PLC, the impact on the company’s financial performance was very weak. On ALEX Industries, the findings show that CSR only has positive impact on the company’s market share, the impact on financial performance and sales growth were all negative. With these, the study concluded that the impact of CSR on marketing performance of these two companies differs and recommended among others,that Companies should be consistent in the implementation of their CSR projects because of its positive impact on marketing performance and that CSR should be measured based on its long run effect and not just the short run.

Materials and Manufacturing of Container and Stem Forgings for the Extrusion Industry

Extrusion tools, such as containers and stems, are expensive components, and it is important to use the most suitable materials to gain a long service life. It has to be pointed out, however, that not only the applied materials determine the life time of these tools, but also melting and forging techniques as well as heat treatment have an essential impact. For many years, Bohler Special Steel Open Die Forge has been a supplier of forged high-quality components for the extrusion industry, e. g. mantels, liner, liner holder, stems, and accessories for containers. This paper reports on the experiences and research activities in the fabrication of forged components for containers and stems for the extrusion industry and covers material selection up to achieved mechanical properties and ultrasonic test results. Moreover, heating and Finite Element Method (FEM) modelling of stress distributions in the container during the extrusion process in order to optimize and predict the lifetime of these components are discussed. From the material side, the focus is set on the classical 5% chromium steel class, up to the high-alloyed and sophisticated Maraging steels for stem application, mainly in indirect extrusion processes, with the highest compressive stresses required.

Technical-economic evaluation of severe plastic deformation processing technologies—methodology and use case of lever-arm-shaped aircraft lightweight components

This paper presents an innovative methodology for integrated technical-economic evaluations of extrusion technologies and aims to show potentials of severe plastic deformation (SPD) technologies. Extrusion technologies and processes such as SPD have a strong influence on properties of aluminium-based lightweight materials. Hence, research and development regarding such processes may contribute to gain competitive advantages for companies as they can differentiate from competitors by offering or processing materials with distinctive properties (e.g. light weight and high yield strength) causing customer’s benefit. Consequently, it is of great importance for companies of the aluminium extrusion industry to select technologies that are promising from both a technical and an economic point of view. Using the integrated methodology, selected SPD technologies are analysed. The application to the use case of lever-arm-shaped aircraft components shows that these technologies bear technical as well as considerable economic potentials: extrusion at room temperature can increase yield strength by 25% compared to commercial extrusion at a similar level of manufacturing costs and the monetary appraisal of the benefits of lower weight for the users of aircraft components indicates a significant economic potential of extrusion at room temperature.