Profile Extrusion Research Articles

Optimization Design of Cooling System of Vacuum Calibrator for Plastics Profile Extrusion

Plastic profile produced by extrusion die should be cooled down and calibrated by calibrator ,so the proper design of the cooling system in calibrator was very important to the profile quality .The cooling channels in calibrator were preliminarily designed according to target function, and peculiar heterotype optimum designs of the local cooling channels were carried out by means of numerical simulation , the cooling effect was improved obviously ,Based on enterprise resource planning ERP system and parallel project computer aided design/computer aided Engineering CAD/CAE intellectualized data-base network, design for the cooling system was more reasonable, and could meet the demands of customers much better.

Oral bioavailability of silymarin phytocomplex formulated as self-emulsifying pellets

The objective of this study was to develop new solid self-emulsifying pellets to deliver milk thistle extract (silymarin). These pellets were prepared via extrusion/spheronisation procedure, using a self-emulsifying system or SES (Akoline MCM®, Miglyol®, Tween 80®, soy lecithin and propylene glycol), microcrystalline cellulose and lactose monohydrate. To select the most suitable formulations for extrusion and spheronisation, an experimental design of experiences was adopted. The screening amongst formulations (13 different blends) was performed preparing pellets and evaluating extrusion profiles and quality of the spheronised extrudates. The pellets were characterised for size and shape, density, force required to crush them. Although more than one type of pellets demonstrated adequate morphological and technological characteristics, pellets prepared from formulation 7 revealed the best properties and were selected for further biopharmaceutical investigations, including in vitro dissolution and in vivo trials on rats to study serum and lymph levels after oral administration of the pellets. These preliminary technological and pharmacokinetic data demonstrated that extrusion/spheronisation is a viable technology to produce self-emulsifying pellets of good quality and able to improve in vivo oral bioavailability of main components of a phytotherapeutic extract of more than 100 times by enhancing the lymphatic route of absorption.

Effects of Lubricant Content on Extrusion Processing and Mechanical Properties of Wood Flour-High-density Polyethylene Composites

Wood plastic composite (WPC) development has been facilitated by the economical extrusion of WPC profiles for various applications. The physical and mechanical properties of WPC products can be optimized by regulating extrusion processing conditions and material formulations. Rectangular WPC profiles were produced with varied high-density polyethylene (HDPE), wood fiber (WF), and lubricant contents under different extrusion conditions in a twin-screw extruder extrusion line. Optimal tensile and flexural properties were obtained with 50 wt% WF at 7 and 3 wt% lubricant and maleated polyethylene (MAPE) contents. The apparent shear viscosity of the WPC melts decreased gradually with increased lubricant content. Hence, for practical applications, a combination of HDPE grade, WF, lubricant, and MAPE contents can provide the benefits of lower shear viscosity while maintaining the mechanical properties and surface smoothness of WPC profiles.

Extrudate swell of linear and branched polyethylenes: ALE simulations and comparison with experiments

Extrudate swell is a common phenomenon observed in the polymer extrusion industry. Accurate prediction of the dimensions of an extrudate is important for appropriate design of dies for profile extrusion applications. Prediction of extrudate swell has been challenging due to (i) difficulties associated with accurate representation of the constitutive behavior of polymer melts, and (ii) difficulties associated with the simulation of free surfaces, which requires special techniques in the traditionally used Eulerian framework. In a previous work we had argued that an Arbitrary Lagrangian Eulerian (ALE) based finite element formulation may have advantages in simulating free surface deformations such as in extrudate swell. In the present work we reinforce this argument by comparing our ALE simulations with experimental data on the extrudate swell of commercial grades of linear polyethylene (LLDPE) and branched polyethylene (LDPE). Rheological behavior of the polymers was characterized in shear and uniaxial extensional deformations, and the data was modeled using either the Phan–Thien Tanner (PTT) model or the eXtended Pom–Pom (XPP) model. Additionally, flow birefringence and pressure drop measurements were done using a 10:1 contraction–expansion (CE) slit geometry in a MultiPass Rheometer. Simulated pressure drop and contours of the principal stress difference were compared with experimental data and were found to match well. This provided an independent test for the accuracy of the ALE code and the constitutive equations for simulating a processing-like flow. The polymers were extruded from long ( L/ D = 30) and short ( L/ D = 10) capillaries dies at 190 °C. ALE simulations were performed for the same extrusion conditions and the simulated extrudate swell showed good agreement with the experimental data.

A Study on Magnesium Alloy Substitution Design and Analysis for Automotive Seat Back Frame

A magnesium alloy substitution design for an automotive seat back frame is carried out. With the magnesium extrusion profiles and the stamping panel integrated, the weight of the seat back frame is reduced by 41.3% and the lightweight goal is achieved. At the same time, the magnesium alloy stamping panel is processed warm forming analysis and verified the formability of the magnesium alloy panel. Numerical calculations comparing the original structure and the substitution design are performed with finite element software, which ensured that the performance indicators such as the mode, the strength and the stiffness defined by related regulatory requirements are all realized. At last, a magnesium alloy substitution design has been proved to be successful.

A macroscopic approach towards the finite element simulation of tapping and thread milling of continuously reinforced extrusions

The Finite Element Analysis (FEA) is a suitable tool for the process design and the determination of technical failure. Within this paper, the FEA is used for simulating and analyzing the thread milling process and the tapping process for reinforced lightweight extrusion profiles. Two different finite element models are developed to simulate both processes. An elastic material behavior is implemented in the simulation. For the tapping process, the computed stresses during the process as well as the geometrical displacements are considerably higher than the stresses computed for the thread milling operation. This is caused by the lower mechanical loads occurring in the thread milling process. The results can be used to identify areas of high stresses which may cause material failure. Moreover, both processes can be analyzed with respect to their influence on the workpiece. The simulation results are compared to experiments.

Design, optimization, and manufacturing of a multiple‐thickness profile extrusion die with a cross flow

AbstractThis article presents a procedure to achieve a uniform outlet flow of molten polymer for a complex die profile with various thicknesses in die outlet cross section. According to a specific optimization methodology, the die was optimized based on varying die land length. The scope of this article includes: 3D flow simulation, optimization of the die velocity outputs based on the results of simulation process, and comparison of numerical predictions with the experimental data. Finally a significant result obtained by this work indicates higher ratio of the land length to the height of the zone with cross flow rather than the zones that are directly fed by the extruder. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers.

Control Model for an Elastomer Extrusion Process Obtained via a Comparative Analysis of Data Mining and Artificial Intelligence Techniques

Some elastomer profile extrusion processes in the automotive industry are still hard to control, generally because they are open loop systems with continual changes in manufacturing conditions. It is at the start-up stage that most time and raw materials are lost. This article describes the development of a dynamic extruder velocity control model that is capable of learning from good start-ups in earlier in manufacturing processes. The process of creating the model focuses on selecting the best technique from a set of data mining (DM) and artificial intelligence (AI) algorithms, which are put to the test with a database containing historical data on the start-up processes that have reached the steady state most quickly in the past. With the new models obtained, the process can be automated, and the time required for start-up in profile manufacturing can be reduced. This will result in increased output, higher quality, less faulty material and lower stress levels among production workers.

Processing properties of polypropylene with a minor addition of silicone oil

AbstractProcessing‐related properties of a polypropylene (PP)/silicone oil blend were investigated. It was found that an addition of a small amount (∼2 wt%) of silicone oil, a low molecular weight linear poly(dimethyl siloxane) (PDMS), drastically changed the rheological properties of PP. The PDMS seemed to work both as an internal lubricant and an external lubricant in the blend system. In particular, the apparent viscosity of the blend in capillary rheometry was approximately 10 times lower than that of virgin PP. The local minima in the viscosity versus shear rate curve in capillary rheometry and the gap‐dependency of viscosity in parallel‐plate rheometry implied the existence of a slip wall condition, caused by the formation of a thin lubricant layer at die walls. Thermal analyses and mechanical tests showed that the thermal and mechanical properties of the blend were nearly unaffected by the minor addition of silicone oil. The blend was tested in a profile extrusion process, and a significant reduction in die swell and profile distortion was achieved. The jet stretchability or spinnability in fiber spinning was also greatly improved with the minor addition of silicone oil. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers

Towards the flexible and near-net-shape production of three-dimensionally curved extrusion profiles

The present paper describes the new developments in continuous extrusion of curved profiles by a flexible production method which is composed of a short process chain starting with the extrusion press, a deflection tool, one robot for the flying cutting of the profile and another robot for supporting and handling the profile. Because of the flexibility of this complete system according to the profile curvature it is convenient for small-volume production. In order to reach high profile accuracy all kinematic systems in the process chain have to be synchronized with the profile speed caused by the extrusion process. The results of the investigation of different existing synchronization methods identify the need for an additional measuring system to compensate the large deviation of the cut profile length. By adjusting parameters of the synchronization the accuracy of the profile length could be strongly improved. Furthermore influencing parameters like die deformation during the extrusion process are measured and combined with the results of the cut profile length over the process time.

Processing Behaviour of High-cis Polybutadiene in Rubber Compounds

Compounding and extrusion are critical steps in the production of rubber compounds of a reliable quality within a given timeframe and hence at a reasonable cost. The materials used - including the rubber types -are varied in order to obtain improvements in product performance. One of the most important of the synthetic rubbers is neodymium polybutadiene (NdBR) which, because of its exceptional microstructure and macrostructure, offers outstanding properties. Through the use of high-cis NdBR, marked improvements have been obtained in end products in terms of dynamic performance and good fatigue and wear characteristics. At the same time, however, the processing behaviour of this type of rubber requires adjustments to be made at the compounding and extrusion stage. This can lead to problems in the handling of the milled sheet and profiles, resulting for example in severe surface roughness or die swell. In extreme cases the benefits of NdBR can be masked altogether if no adjustments are made to the processing stages. This paper presents countermeasures to improve the processability of NdBR by adapting the compounding and extrusion conditions to its specific requirements. The ratio of viscosity and elasticity is specific to each type of rubber and therefore requires individual adjustment of the processing conditions. We show that under appropriately adjusted conditions, even using NdBR grades with the highest molecular weights (e.g. Buna CB22), short compounding times and smooth milled sheets and extrusion profiles with a glossy surface can be obtained. Under these conditions neodymium polybutadiene rubbers provide a basis for an ideal combination of excellent material properties and improved processing behaviour. The positive characteristics of NdBR are retained when it is used in blended rubbers such as an SSBR/BR blend. The rules regarding the optimisation of process conditions for pure NdBR systems apply here too.

Understanding metal flow in aluminium extrusion by means of emptying diagrams

Use of emptying diagrams is a useful approach to fully understand the implications of differences in the characteristics of metal flow in metal extrusion processes. The concept of back-calculation of straight transverse lines inside the final extrusion back to their location at earlier stages of extrusion was early developed. When this principle is used to back-calculate a full grid pattern inside an extruded rod back to the initial stage in the unextruded billet; a so-called emptying diagram is obtained. Today such back-calculation is precise, straight-forward and fast by help of FEA. It is shown what kind of information regarding metal flow that can be obtained from emptying diagrams in extrusion processes like forward, backward and hollow profile extrusion.

Sensitivity analysis for the design of profile extrusion dies

This paper proposes a procedure for design sensitivity analysis using the direct differentiation method which can be easily included into a finite element code. By a reformulation of the governing equations, it is shown that the derivatives necessary to evaluate the sensitivity of a given performance measure corresponding to the current design configuration can be obtained through a post-processing step by the same finite element solver used to solve the discrete state equations. The procedure is illustrated for some examples with known analytical expression of the sensitivity and then applied to several practical problems in the design of an extrusion process.

Numerical Investigation of Viscoelastic Flow and Swell Behaviors of Polymer Melts in the Hollow Profile Extrusion Process

The viscoelastic flow and swell behaviors of polymer melts in the profile extrusion process can significantly influence the performance and dimension of the final products. In the study, the viscoelastic flow pattern of a commercial low density polyethylene (LDPE) extruded through out of the hollow profiled extrusion die is investigated by means of finite element simulation. The mathematical model of three-dimensional viscoelastic flow and swell of polymer melts is established with a differential Phan-Thien and Tanner (PTT) constitutive model. A penalty method is employed to solve the non-linear problem with a decoupled algorithm. The computation stability is improved by using the discrete elastic-viscous split stress (DEVSS) algorithm with the inconsistent streamline-upwind (SU) scheme. A streamface-streamline method is introduced to adjust the swelling free surface of the extrudate. The essential viscoelastic flow characteristics of LDPE flowing through out of the hollow profile extrusion die is investigated based on the proposed numerical scheme. Both the redistribution of flow velocity and the release of stress are found to be the reasons for the swell phenomenon.

Finite Volume Simulation and Multi Parameters Optimization on Extrusion of Complex Aluminum Profile

In this paper, finite volume method (FVM) is adopted to simulate complex irregular aluminum profile extrusion process. The basic theory of FVM, the materials model, friction model, and a computer aided optimization (CAO) model based on orthographic experiments, artificial neural network (ANN) and genetic algorithm (GA) are presented. A complex aluminum profile extrusion is simulated and optimized. The results show FVM simulation is a good way for the description of material flow, and mesh distortion could be avoided effectively. Optimal values of multi parameters are also obtained. Experiment shows good fit among the simulation, optimization and the experimental results.

FVM Simulation of Large Deformational Aluminum Extrusion Process and Die Bearing Optimization

The mathematic model of three-dimensional aluminum profile extrusion processes using finite volume method (FVM) was established in this paper. Basic theory and key technologies of this model were researched and built. Non-orthogonal blocked structured girds were used to fit complex geometries. Volume of Fluid (VOF) scheme was used to capture the free surface of the deforming materials. A program AE-FVM was written according to the above theories and equations. A thin walled aluminum profile extrusion process was simulated and optimized using AE-FVM. The simulation results were also compared with that simulated by Deform-3D and SuperForge in the same conditions. The feasibility of the mathematic model built in this paper was demonstrated by the simulation results comparison.

Component-specific scale for inline quality assurance of spatially curved extrusion profiles

Spatially curved Al-extrusion profiles are often used for lightweight frame structures in vehicle manufacturing. Within the Collaborative Research Centre SFB/Transregio 10, an automated product-flexible process chain is established in order to produce and machine such profiles and to join them into frame structures. One of the biggest challenges of this process chain consists in handling, clamping and machining variably formed profiles with precision and without having to change the mechanical system. For this, both the contour of the profile and the position and orientation of the profile during the process have to be determined. In order to have this information provided from inside the process chain, a component-specific scale was developed and realised for the contour detection and precision positioning of multi-dimensionally curved extrusion profiles. The scale is applied onto the surface of the profile by a laser. To determine the contour, the scale is scanned using digital image processing and the profile is measured by a laser triangulation sensor. This establishes the relation between component scale and profile contour. If required, the position of the profile can be readjusted by scanning individual markings again during machining. It is not necessary to re-measure the entire profile contour. The process can be used for different profile contours and profile lengths without having to change the mechanical system. The first section of this article describes the approach for contour detection and precision positioning and its validation for straight profiles, 2D curved profiles and 3D curved profiles with a test rig. Then, the implementation of the validated process into a process chain is described, including the inline application of the scale, the inline profile measuring and the precision positioning of spatially curved profiles during machining.

熱可塑性エラストマーの今そして未来 高溶融張力エチレン系エラストマーＨＭＳ ＰＯＥ及びオレフィンブロック共重合体ＯＢＣの特徴と適用事例

Novel polyolefin elastomers, HMS POE and OBC were introduced. HMS POE is a high melt strength ethylene-α-olefin random copolymer with certain level of long chain branches and high molecular weight which have provided unique rheological properties such as higher melt strength, higher melt elasticity, shear shining property under a given shear and strain hardening. These rheological attributes have enabled higher through-put for extrusion profile, thermoforming sheet without any tear and webbing and stable parison retention for blow molding. Moreover, OBC is a multi-block copolymer consisting of hard- and soft-blocks covalently bonded together. Due to the presence of crystalline hard blocks, it provides heat resistant elastomer, faster crystallization rate leading to cycle time reduction and comparable compression set property to that of cross-linked TPV products.

Wood Polymer Composites Technology Supporting the Recovery and Protection of Tropical Forests: The Amazonian Phoenix Project

The Amazon Rain Forest has attracted worldwide attention due its large scale services to climate and also due to the green house gas emissions arising from deforestation. Contributing to the later and detrimental to the former, timber logging in the region has very low efficiency (only 16% in the production chain). Such timber extraction, often referred to as selective logging, has been claimed as a sustainable extractive industry, because the forest is said to restore itself through regenerative growth. But forest regeneration in the Amazon occurs naturally only in a very limited scale, resulting that large scale, low efficiency logging poses a big treat to the functional integrity of the biome, supplying to the market only a fraction of what it could if done differently. So, instead of extracting big centennial logs from the forests, the Amazonian Phoenix project proposes that large expanses of degraded lands be reforested using pioneer plants species from the forest itself. These plants have the capacity to heal gaps in the canopy, being able to grow and produce woody biomass in very extreme conditions. The idea is to mimic the regenerative dynamics of the natural ecosystem in short cycle agrosilvicultural production areas, utilizing a variety of technologies to transform raw fibers from these fast growth native plants into a variety of materials with high aggregated value. This communication presents the research on natural fibers by the Polymeric Composites Group within the Amazonian Phoenix Project. Sustainable technologies employing materials with good and responsible ecological footprints are important and necessary stimulus for a change in the destructive economical activities present in the Amazon frontiers. The relatively well established wood polymer composites technology, for example, is a good candidate solution. Two research and development fields are proposed: the first one considers production systems with simple and cheap machinery, to facilitate technology assimilation by rural communities in the Amazon. The second one aims at developing composite materials with advanced production technology, like profile and sheet extrusion and injection molding. The source of the fibers would be both the short cycle agrosilviculture with softwood species, on already deforested lands, and the hardwood residues from operating sawmills. Preliminary results show that softwood fibers act as potentially important reinforcement for synthetic plastics.

Moisture movement in wood polypropylene composites

Moisture movement in an extruded wood polypropylene composite was evaluated by exposure to high humidity and immersion of the material in both fresh and seawater. The saturation moisture content was approximately 20 and 19% when exposed to distilled water and seawater, respectively. The moisture diffusion coefficient (Dm) of thin specimens exposed to high humidity was 3.4 × 10−8 cm2\( / \)s. The Dm of small cubic specimens with extruded surfaces removed submerged in distilled water and seawater were estimated to be 3.1 and 2.3 × 10−8 cm2\( / \)s, respectively. Use of these diffusion coefficients overestimates the rate of moisture movement in larger extrusion profiles indicating the role of transport phenomenon other than diffusion.