Extrusion Dies Research Articles

Recent Trends in Nitrogen Cooling Modelling of Extrusion Dies

Nitrogen cooling has been identified as a powerful industrial solution for the hot extrusion process to remove heat in the die and in the profile. The complexity involved in the design of cooling channels depends on many factors, including the cooling path, its position with respect to the hottest zones as well as the nitrogen phase change that strongly affects the heat removal capacity. However, the industrial approach is still stuck in the empirical and based-experience practices that too often strongly limit the possibilities of obtaining a performing cooling solution. In this context, this work intends to summarize and discuss the advanced recent trends in the design of cooling channels for extrusion dies proposed by the authors based on the numerical approaches, with the final aim to propose possible solutions to fill the current gaps of the suboptimal industrial approaches.

Automated Optimum Extrusion Die Design and Profile Quality Control Based on Simulation

The paper presents the experience of development and implementation of an integrated approach of extrusion simulation with the automated design of the dies as a new way to speed up the technology development and its optimisation based on the QForm UK Extrusion simulation program and QForm Extrusion Die Designer (QExDD) design system. Bearing and prechamber optimisation types are considered for the porthole design. Welding quality and possible streaking lines in the profile are analysed for the tool construction with optimised prechamber contour.

Parametric Study for Damage Optimization in Two-Stage Cold Extrusion Dies by Implementing Taguchi Method and ANN Method in Genetic Algorithm

Parametric Study for Damage Optimization in Two-Stage Cold Extrusion Dies by Implementing Taguchi Method and ANN Method in Genetic Algorithm

Effect of Weld Seams on Corrosion Following Porthole Die Extrusion of Aluminum Tubes

Effect of Weld Seams on Corrosion Following Porthole Die Extrusion of Aluminum Tubes

The Effect of the Bridge’s Angle during Porthole Die Extrusion of Aluminum AA6082

During the porthole die extrusion, the separated metal streams are welded together in the welding chamber. The conditions under which this occurs and the integrity of weld seam in the extrudate are impacted by the design of the bridge, including features such as its shape and dimensions. In this research, the commercial finite element method (FEM) software package, DEFORM, was used to run a series of simulation experiments in order to quantitatively understand the relationship between the bridge design and the thermal mechanical history experienced by the material during welding and the impact this has on final weld seam quality. The bridge can be roughly divided into two parts: the lower part, close to the welding chamber, and the upper part, which initially split the billet into metal streams. The results showed that increasing the lower bridge angle led to slightly higher extrusion loads and higher extrudate exit temperatures. As the lower bridge angle increased, creating a streamlined profile to a blunt profile, a dead metal zone formed under the bridge that produced higher strains near the surface of the material. In contrast, changes to the geometry of the upper bridge had little effect on the porthole die extrusion process or the thermal mechanical conditions experienced by the material.

Optimization Design Method of Plastic Extrusion Die for Product Geometric Accuracy

Optimization Design Method of Plastic Extrusion Die for Product Geometric Accuracy

Knowledge Modelling for the Smart Design of Aluminium Profile Extrusion Dies

Aluminium profiles are widely used in distinct fields since their excellent physical properties, and the quality and efficiency of producing aluminium profiles are largely depending on the extrusion dies. Therefore, the design of the aluminium extrusion die is the most significant part. However, the extrusion die design is a complex process, which includes plenty of data, information, and knowledge. In production, reusing part of the previous design information and knowledge can improve design efficiency. In this case, this study has explored the way to systematically model the design knowledge generated during the aluminium extrusion die design process. Firstly, knowledge representation models have been created, acting as the schema layer of the domain knowledge graph for the aluminium extrusion die design. This knowledge graph is subsequently used as the repository of a Web-based smart design system. By providing the three key functionalities of knowledge representation, semantic retrieval and intelligent recommendation, the smart design system can help engineers effectively reuse previous design knowledge to improve design efficiency and quality.

Shape Optimization for Temperature Regulation in Extrusion Dies Using Microstructures

Abstract Plastic profile extrusion—a manufacturing process for continuous profiles with fixed cross section—requires a complex and iterative design process to prevent deformations and residual stresses in the final product. The central task is to ensure a uniform material velocity at the outlet. To this end, not only the geometry of the flow decisively influences the quality of the outflow but also the temperature profile along the flow channel wall. It is exactly here that this work contributes by presenting a novel design approach for extrusion dies that will allow for optimal temperature profiles. The core of this approach is the composition of the extrusion die through microstructures. The optimal shape and distribution of these microstructures is determined via shape optimization. The corresponding optimization procedure is the main topic of this article. Special emphasis is placed on the definition of a suitable, low-dimensional shape parameterization. The proposed design-framework is then applied to two numerical test cases with varying complexity.

Influence of Operating Temperature on the Service Life of Aluminum Extrusion Dies.

sThe article investigates the effect of temperature and annealing time on the surface quality of WNLV nitrided steel used for the production of dies for extrusion of aluminum alloys. Eight annealing variants were tested, differing in the total annealing time at temperatures of 460 °C and 590 °C. The results show the effect of the annealing time on the width of the diffusion layer, which increased with the increasing length of the annealing time. The hardness decreased as the annealing time increased. It was found that annealing of the steel causes its oxidation. The oxide layer formed consisted of two layers, more specifically, an Fe2O3 oxide layer and a lower Fe3O4 oxide layer adhering to the steel surface. The surface of sections pressed on oxidized matrices was tested. The roughness of the surface of the oxide layers was also tested. The research revealed that an increase in the surface roughness of the oxides deposited on the matrices causes an increase in the roughness of the extruded sections. These results can potentially be used to improve the efficiency of the extrusion process and the quality of the extruded sections.

Derivation of a Qualitative Model for the Spatial Characteristic Wavelength of Extrusion Flow Instabilities: Investigation of a Polybutadiene Rubber through Capillary, Slit and Complex Geometry Extrusion Dies

AbstractThe extrusion flow instabilities of commercial polybutadiene (PBD) are investigated as a function of the different extrusion die geometries, such as round capillary, slit, and complex cross‐section profile slit dies via capillary rheology. Qualitative models are used to fit the experimental data for the spatial characteristic wavelength (λ) of the appearing extrusion flow instabilities. A new qualitative model for the slit die geometry, rectangular cross‐section, is derived based on the theoretical concept of the “two layers” extrudate and the force balance at the die exit region. The proposed qualitative model for the slit die geometry is used to predict the spatial characteristic wavelength (λ) for extrudates obtained by complex cross‐section profile slit die geometries similar to industrial manufacturing. Correlation between the ratio of the extensional (Ys) and shear (σx) stress at the die exit area and the characteristic dimension, height H for slit dies and diameter D for round capillary dies, is presented. Moreover, a geometry‐dependent model is used to predict the spatial characteristic wavelength (λ) of the extrusion flow instabilities from a round capillary die to a slit die and vice versa.

Assessment of the Optimization Strategy for Nitrogen Cooling Channel Design in Extrusion Dies

Aluminum extrusion is an efficient industrial process. However, one of the main problems is related to the temperatures developed during the process that can detrimentally affect the achievable productivity, profile quality and/or die life. Cooling of the die with liquid nitrogen represents an efficient solution to overcome this limit but a further issue arises lying in the number of process and design variables that need to be managed in order to set-up of an efficient system. In this context, a 3D FE model of the extrusion process, coupled with a 1D model of the cooling channel, previously proposed by the authors, has been integrated in an optimization platform in order to iteratively and automatically adjusts the channel geometry and the process variables gaining to a final optimal solution in terms of thermal balance, cooling efficiency and nitrogen consumption. The original channel design used during the extrusion of industrial hollow AA6060 profile guaranteed an efficient but unbalanced cooling with a maximum temperature deviation of 60 °C registered by the thermocouple positioned around the bearings. The optimized designs showed temperature deviations below the 16 °C as well as the reduction of 50% in terms of nitrogen consuming.

Effect of Magnesium Powder Application on the Microstructure and Properties of Rods Extruded by the Forward-Backward Rotating Die Extrusion Method.

The effects of severe plastic deformation (SPD) with a forward-backward rotating die (KOBO extrusion) on pure magnesium, in the form of cold-compacted powder, sintered powder, or cast ingots as reference, were examined. This method is known to reinforce metals, but the role of the initial form of magnesium applied in the fabrication of metal-based rods, as well as related phenomena, has not been characterized until now. The problem is important in the potential processing of commercial metal powders, the recycling of metal shavings, and the fabrication of metal matrix composites with discontinuous reinforcing phases. In the presented experiments, rods of 8 mm in diameter and 400 mm in length were obtained, and the structural effects induced by KOBO that occurred on a macro- and microscale on the surface and cross sections were characterized. Changes in the size and orientation of α-Mg crystallites were determined by XRD. The porosity, hardness, tensile strength, and compressive strength were measured, and the mechanisms of decohesion dependent on starting metal form were analyzed. After KOBO extrusion, significant differences were observed in the microstructure and properties between the materials derived from cold-compacted powder, sintered powder, and reference cast magnesium. Due to the application of KOBO, apart from α-Mg grain refinement, the MgO derived from the initial powder’s surface was refined to fine regular particles surrounded by magnesium. Their bands curved in the perpendicular plane and were oriented with the extrusion direction of the formed network, which augmented some mechanical properties and changed the decohesion mechanism. The conducted experiments revealed that before extrusion by KOBO, the magnesium powder required sintering under pressure.

Study the Effect of Extrusion Speed and Die Angle on Relative Extrusion Pressure of Aluminum Alloy AA6061

Theoretical and experimental study of die angle, and extrusion speed effect on relative extrusion pressure of annealed AA6061 aluminum alloy have been carried out in this research. Two theoretical fields have been employed, rigid-plastic field and mixed field, to predict the relative extrusion pressure. A FORTRAN program has been developed to calculate the relative extrusion pressure and its compounds. The tests have been conducted with various, die angle (30°,60°,90°,120°,150°) and various extrusion speed (10,7,3) mm/min.The results showed an increase in shear power and friction power with increasing die angle, while no effect was observed on the internal power of deformation. It was also found that the relative extrusion pressure, the inhomogeneous strain, and the shear strain across the section increase as the die angle and extrusion speed increase. Experimental tests showed that the optimum die angle was 60° while the optimum die angle was between 35°-90° and 46° according to the mixed field and the rigid- plastic field respectively.

An Improvement on Design of Sheet Extrusion Dies

Abstract On the basis of the method of representative values and the flow pattern, that is, the position of the isobars parallels to the die orifice (PIPDO), the design of dies for the sheet and annular parisons is improved in the present paper. Since this pattern includes the effects of the sloped manifold and the die design for the circular manifold are independent of flow rate and the polymer viscosity, the distribution system of a die gives better uniformity of flow. In the previous study [1] a defect is found, that is, the calculated position of the path of the island area lags behind actual position. This defect is eliminated, and the modified equation is obtained. Another flow pattern, the pressure loss on all flow path is equal (PLFPE), is introduced. The equivalency of the above two flow patterns is proved theoretically. Although the flow uniformity isn’t perfect in the simplified analytical design of dies proposed in the previous paper, this simplified design is still of advantages. Therefore, its design criterion is put forward in this paper.

UDDEHOLM QRO 90 SUPREME

Abstract Uddeholm QRO 90 Supreme is a high-performance chromium-molybdenum-vanadium alloy hot-work tool steel. The combination of high temperature strength, temper resistance and thermal conductivity exhibited by Uddeholm QRO 90 Supreme is unparalleled. Thus Uddeholm QRO 90 Supreme exhibits improved service life in die casting and extrusion of nonferrous metals, and in forging and extrusion of steel. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on heat treating and machining. Filing Code: TS-825. Producer or source: Uddeholms AB.

Designing Porthole Aluminium Extrusion Dies on the Basis of Explainable Artificial Intelligence

Designing Porthole Aluminium Extrusion Dies on the Basis of Explainable Artificial Intelligence

Effect of Extrusion Ratio on Mechanical Properties of TCP/PLA Bone Fixation Screw Molded by Extrusion Die Forging

Metal bone fixation devices are used in the treatment of bone fractures. However, metallic materials cause inflammation in the body. In this study, we focused on bioabsorbable composite material of poly(lactic acid) (PLA) and tricalcium phosphate (TCP). However, the mechanical properties of TCP/PLA composites are lower than those of metal materials. In order to improve the mechanical properties of TCP/PLA bone fixation screws, molecular orientation by extrusion die forging was focused under various extrusion ratios (ER) and TCP contents. The orientation of molecular chains depends on the forging conditions. The purpus of this study is investigation effect of forging condition on mechanical properties of TCP/PLA scres. Then, screws were formed by extrusion die forging at ER 1.3, 4 and 8, and shear strengthe of the screws was measured. As a result, the shear strength increased with ER, and the maximum shear strength was observed at ER 4.

Reduced Flow Model for Plastics Melt Inside an Extrusion Die

AbstractIn this work, we study the application of Model Order Reduction (MOR) to the flow of plastics melt in an extrusion die. The process is described with a non‐linear model consisting of the Stokes equations in combination with a shear‐thinning material model. The reduction is performed through a Proper Orthogonal Decomposition (POD) approach with subsequent projection. We perform an a‐posteriori error analysis for a quantity of interest, based on the full‐ and reduced‐order solutions. Finally, we explore the computational speedup to prove the aptitude of the reduced model in the context of many‐query scenarios.

Microstructure and Its Influence on the Welding Quality of 6063 Aluminum Alloy Porthole Die Extrusion.

Extrusion experiments and 3D numerical modeling were conducted to investigate the dynamic recrystallization and welding quality of a 6063 aluminum alloy hollow square tube extruded by a porthole die at the ram speeds of 3 mm/s, 7 mm/s, 9 mm/s and 11 mm/s. The results showed that average grain size of hollow square tube extruded at the ram speed of 7 mm/s was the smallest. The profile extruded at the ram speed of 3 mm/s exhibited the highest expansion ratio. Dynamic recrystallization (DRX) fractions were highly variable at different ram speeds. DRX fractions in the matrix zones were higher than those in the welding zones, resulting in smaller grain sizes in the matrix zones. Mechanical properties in the welding zones and matrix zones was different. A local strain concentration would occurred during expansion, which would affect the welding quality. Finally, it was found that the uniform microstructure near the welding line would also affect the welding quality.

A Multi-Rheology Design Method of Sheeting Polymer Extrusion Dies Based on Flow Network and the Winter-Fritz Design Equation.

In the polymer sheet processing industry, the primary objective when designing a coat-hanger die is to achieve a uniform velocity distribution at the exit of the extrusion die outlet. This velocity distribution depends on the internal flow channels of the die, rheological parameters and extrusion process conditions. As a result, coat-hanger dies are often designed for each polymer based on its individual rheological data and other conditions. A multi-rheology method based on a flow network model and the Winter–Fritz equation is proposed and implemented for the calculation, design and optimization of flat sheeting polymer extrusion dies. This method provides a fast and accurate algorithm to obtain die design geometries with constant wall-shear rates and optimal outlet velocity distributions. The geometric design when complemented and validated with fluid flow simulations could be applied for multi-rheological fluid models such as the power-law, Carreau–Yasuda and Cross. This method is applied to sheet dies with both circular- and rectangular-shaped manifolds for several rheological fluids. The designed geometrical parameters are obtained, and the associated fluid simulations are performed to demonstrate its favorable applicability without being limited to only the power-law rheology. The two such designed dies exhibit 32.9 and 21.5 percent improvement in flow uniformity compared to the previous methods for dies with circular and rectangular manifolds, respectively.