Extrusion Force Research Articles

Influence of Equal Channel Angular Extrusion on the Behavior of Lead Alloy

Equal Channel Angular Pressing (ECAP) is the most promising material processing technique involving severe plastic deformation, and has been extensively employed and analysed. The aim of this work is to examine the influence of ECAP on the behaviour of Lead alloy. The technique was applied to Lead alloy at room temperature using route C, at channel angles of 450, 600, 750, 900 and 1050. The materials were processed up to five ECAP passes. Hardness test, impact test, and microstructural changes of the processed materials were examined. Results show that extrusion force reduces as the strain level increases and that dynamic recrystallization and structural changes reduce the material hardness for all angles of ECAP. All the angles absorbed their least amount of energy at their 5th pass. Analysis of microstructure images also revealed that increasing the strain level leads to break down and dissolution of Antimony rich precipitate.

On recoated powder quality with a forward rotating flexible roller in laser powder bed fusion of 30 wt% 5 μm SiCp/AlSi10Mg composites

This paper proposes a new powder recoating mechanism named forward rotating flexible roller (FRFR) which aims to solve the poor powder flowability problem brought by the aggregation effect of the fine particles in the mixed 30 wt% 5 μm SiC and 55 μm AlSi10Mg powder. An initial extrusion force instead of a gap between the flexible roller and powders is used to improve the recoated powder density, while the recoated powder layer thickness is proved to be controllable. An industrial camera and a laser displacement sensor were used to estimate the recoated surface filling rate and recoated surface profile. The mixed powder was recoated with an FRFR on a baseplate at first, the achieved surface filling rate was the same as that of 55 μm AlSi10Mg recoated with a rubber blade. Then 120 layers of mixed powder were recoated continuously with FRFR, the recoated surface profile within a single layer and between multiple layers were compared with the rubber blade recoated AlSi10Mg, their difference is insignificant. Furthermore, composite parts with different shapes were successfully made with the FRFR. This technique is proved to be promisihfcang for laser powder bed fusion of fine particle ceramic and metal mixed powder.

Feasibility study of a novel multi-container extrusion method for manufacturing wide aluminium profiles with low force

Extrusion profiles are extensively used in industries and any improvement in the process could potentially have a large impact on energy and cost savings. In this study, a novel extrusion method, namely multi-container extrusion, was proposed for producing thin-walled wide aluminium components with low force. Its basic principle is to enable multiple billets to be welded and forced through die orifice simultaneously. To demonstrate its feasibility, a series of studies have been conducted including the experimental design and set-up of multi-container extrusion, microstructural and mechanical characterisations of the extruded components, and the comparison with the existing extrusion method. A three-container extrusion tooling was designed and manufactured to produce wide hollow profiles with plasticine and aluminium alloy AA6063. Optical microscopic observations and tensile tests were carried out for different positions of AA6063 extrudates. For the specimens near the extrudate front (8 mm and 23 mm away), tensile fractures occurred exactly along the distinct welds which were formed when individual billets met inside the die during extrusion. Further away from the extrudate front (83 mm, 98 mm and 113 mm), the welds were hardly observed, and the tensile fractures occurred outside the welds, indicating that good welding quality can be obtained in the multi-container extrusion process. Compared with the conventional porthole extrusion method, three-container extrusion could significantly reduce the required force to about 15 % for extruding the same profile. This study demonstrates that the proposed multi-container extrusion method can form wide profiles and greatly reduce the extrusion force requirement.

Oxidized hyaluronic acid/adipic acid dihydrazide hydrogel as cell microcarriers for tissue regeneration applications

Abstract Hyaluronic acid (HA) is a biopolymer present in various human tissues, whose degradation causes tissue damage and diseases. The oxidized hyaluronic acid/adipic acid dihydrazide (oxi-HA/ADH) hydrogels have attracted attention due to their advantages such as thermosensitivity, injectability, in situ gelation, and sterilization. However, studies are still scarce in the literature as microcarriers. In that sense, this work is a study of oxi-HA/ADH microparticles of 215.6 ± 2.7 µm obtained by high-speed shearing (18,000 rpm at pH 7) as cell microcarriers. Results showed that BALB/c 3T3 fibroblasts and adipose mesenchymal stem cells (h-AdMSC) cultured on the oxi-HA/ADH microcarriers presented a higher growth of both cells in comparison with the hydrogel. Moreover, the extrusion force of oxi-HA/ADH microparticles was reduced by 35% and 55% with the addition of 25% and 75% HA fluid, respectively, thus improving its injectability. These results showed that oxi-HA/ADH microcarriers can be a potential injectable biopolymer for tissue regeneration applications.

An analytical model for predicting the extrusion force for the torsion extrusion process of metals

Torsion extrusion (TE) method as a severe plastic deformation (SPD) process can effectively refine the microstructures and improve the mechanical properties of materials. Accurate and rapid prediction of the extrusion force in the process of TE is an important problem in industry. This paper proposed an analytical model using upper bound method (UBM) for predicting the extrusion force in the TE process. The kinematically admissible velocity field is established based on a continuous spherical extrusion velocity field coupled with a torsional velocity field constrained in a conical die. The torsional angular velocities along the radial and axial directions are assumed with quadratic and cubic function, respectively, due to the radial and axial nonlinearity of torsional velocity in the deformation zone. In addition, considering its complexity, the shape of the deformation zone is mapped to a rectangular zone. By establishing the torsional velocity field in the mapped zone, the torsional velocity field of the deformation zone is obtained according to the mapping relation. The UBM model is validated by comparing the predicted extrusion force with the simulation results obtained from the finite-element method (FEM). Moreover, the influences of the friction factor, reduction ratio and die angle on the extrusion force were investigated as well.

Development of a multi-container extrusion method for extruding lightweight wide plates and sheets

Extrusion of wide plates and sheets of light alloys has been studied over a long period of time, yet the extrudable width of the material is still limited due to high extrusion force requirement. To overcome this drawback, a new multi-container extrusion process is proposed in the research, which allows the production of lightweight plates and sheets with less force compared to that of existing extrusion methods. A lab scale feasibility study system with three containers has been designed and built and tested for AA1060 billets. Experimental work has been carried out with the extrusion temperature of 450°C and extrusion speed of 0.5 mm/s. Optical microscopy observation and tensile tests have been performed for the extruded materials at different positions to investigate the extrusion welding quality between the three extrusion billets. The test results show that the welding quality improves as extrusion progresses and the overall welding quality is stable. This study demonstrates the feasibility of the new multi-container extrusion method.

Optimal Parameters Selection in Advanced Multi-Metallic Co-Extrusion Based on Independent MCDM Analytical Approaches and Numerical Simulation

Multi-material co-extrusion is a complex thermo-mechanical forming process used to obtain bimetallic billets. Its complexity is due to the combination of diffusion phenomena in the interface of both materials together with the high temperature and pressure generated and the different flow stress characteristics created by the joining of dissimilar materials. Accordingly, the selection of optimal process parameters becomes key to ensure process feasibility. In this work, a comparison among different multi-criteria decision making (MCDM) methodologies, together with different weighting methods, were applied to the simulation results by using DEFORM3D© software to select the optimal combination of process parameters to fulfil the criteria of minimum damage, extrusion force, and tool wear, together with the maximum reduction in the average grain size.

Process parameters and system responses in friction extrusion

Friction extrusion is an emerging manufacturing process that imparts improved properties and unique microstructures to materials. In this study, the effects of die features (i.e., the absence or presence of die face scrolling) and process parameters (i.e., die rotational speeds and feed rates) on response variables (e.g., extrusion force, torque, power, and temperature) were investigated. During this work, wires with good integrity and similar geometries were extruded over a range of experimental trials with different rotational speeds and feed rates at a constant extrusion ratio. The extrusion force linearly varies with die advance per revolution, which is the ratio of feed rate and rotational speed. The extrusion energy per kilogram mass of extrudate varies non-linearly and asymptotically such that energy consumption is highest at the lowest feed rate and lowest at the highest feed rate. Relationships among other variables (i.e., die advance per revolution, torque, power heat input, and temperature) also were evaluated to elucidate their interdependences.

Effect of Punch Surface Microtexture on the Microextrudability of AA6063 Micro Backward Extrusion

To apply conventional forming processes to microscale processing, the influence of size effects caused by material properties and friction effects must be considered. Herein, the effects of tool surface properties, such as punch surface texture, on microextrusion properties, such as extrusion force, product shape, and product microstructure, were investigated using AA6063 billets as test pieces. Millimeter-scale, microscale, and nanoscale textures were fabricated on the punch surfaces. Punch texturing was conducted by electrical discharge machining or polishing or using a laser process. The extrusion force increased rapidly as the stroke progressed for all punch textures. Comparing the product shapes, the smaller the texture size, the lower the adhesion and the longer the backward extrusion length. The results of material analysis using electron backscatter diffraction show that material flowability is improved, and more strain is uniformly applied when a nanoscale-textured punch is used. By contrast, when a mirror punch was used, material flowability decreased, and strain was applied non-uniformly. Therefore, by changing the surface properties of the punch, the tribology between the tool and material can be controlled, and formability can be improved.

Quantification of orthodontic loads on teeth in the correction of canine overeruption using different archwire designs

This study quantifies the effects of material, size of the continuous archwires, and level of overeruption on the loads on teeth in the correction of overerupted canines. An orthodontic force test (OFT) was used to measure the 3-dimensional loads delivered by the archwires to the brackets attached to the maxillary right incisors, canine, and premolars. Dentoforms simulating canine overeruptions at the 0.5 mm and 1 mm levels were made from computerized tomography scans. Archwires with 2 types of material (stainless steel [SS] and nickel-titanium [NiTi]) and 2 sizes (0.014-in and 0.016-in) were tested, respectively, on the 0.022 × 0.028-in brackets through elastomeric ligatures. The forces were dominantly intrusive on the canines and extrusive on the first premolars and lateral incisors. The magnitudes of the extrusive forces were about 74% and 52% that of intrusive force on the canines, which range from -0.48 ± 0.01 N to -5.70 ± 0.14 N depending on the wire material, size, and severity of overeruption (P<0.01). The canine intrusive forces created by SS wires were about 3 times higher than that of NiTi wires with the same sizes, 0.016-in archwires were about twice higher than that of 0.014-in with the same materials, and 1 mm overeruption level doubled with respect to 0.5 mm. Significant second-order moment as coupled with the intrusive or extrusive forces. The intrusive and extrusive forces on teeth in the correction of canine overeruption can be quantified by the invitro orthodontic force test, and the effects of the 3 factors significantly affect the loads on the teeth.

Study on the relationship between welding force and defects in bobbin tool friction stir welding

In this paper, the characteristics of traverse force (Fx), lateral force (Fy), and axial force (Fz) in bobbin tool friction stir welding (BTFSW) and their relationship with welding defects were studied. Fx, Fy, and Fz showed periodic oscillations and had sinusoidal waveforms in defect-free joints. Defect formation strongly influenced the variation of welding force, and Fy increased most noticeably in defective joints. The average value of Fy determined whether defects occurred in the weld. The material flow behavior during defect formation was analyzed and it was demonstrated that an increase in Fy was due to severe material deposition on the retreating side (RS), which significantly increased the extrusion force between the pin and the workpiece. Due to the good correlation between welding force and defects, a decision tree model based on the force features in the time and frequency domain was built to predict the welding defects. The accuracy of this model in predicting defects reached 95.3 %. Furthermore, the prediction results showed that Fy was the most sensitive force to the generation of defects, and the average value of Fy was the key feature in predicting whether defects occurred.

CCRobot-IV: An Obstacle-Free Split-Type Quad-Ducted Propeller-Driven Bridge Stay Cable-Climbing Robot

This letter presents CCRobot-IV, the fourth version of a climbing robot designed for bridge cable-inspection tasks. CCRobot-IV inherits design features from the previous CCRobot series, and has improved capability for crossing cables with obstacles such as helical ribs, small metal accessories, and various other obstacles. CCRobot-IV consists of a quad-ducted propeller-driven climbing precursor and an affiliated payload-carrying body. Because a quad-ducted propeller does not depend on friction generated by mutual contact and extrusion, the precursor’s locomotion is decoupled from the surface of the bridge cable and the obstacles on it. When the precursor climbs up to reach the set position, it uses its gripper’s self-locking palms to grasp the bridge cable, which creates a fixed anchor point that allows the payload-carrying body to pull itself up using wires and two winches (which are a type of driving wheel that do not require extrusion force on the cable to produce adhesion and friction). Therefore, the robot’s payload capacity is also decoupled from adhesion to the cable surface, and thus the entire system has obstacle-free operation. Experimental tests and field tests have demonstrated CCRobot-IV’s climbing performance, payload capacity, and potential application utility.

Experimental investigation of 2D-SnS2 hexagonal nanosheets as lubricating additive in the microextrusion process

Micro parts have become inevitable nowadays for a large number of applications in the areas such as space technology, medical science, nano technology, and electronics. This creates a significant need to develop new techniques, and machine tools for micro manufacturing. In the micromanufacturing process, the interfacial friction between the forming tool and the workpiece is uncertain. It has a significant impact on process workability, which is a key factor in material formability. In the current work microtribological behavior of hexagonal 2D-SnS2 nanosheets as lubricating additives is investigated. Upon the usage of nanoadditive lubricant in the extrusion of micro stepped pin, the extrusion force reduced significantly. Due to the presence of nanoadditives an increased surface quality in the extrudates was observed and it was further justified in the surface roughness results. The raise in temperature leads to more uniform hardness, with a significant reduction of coefficient of variation along with improved material formability. This research work provides a deeper understanding of the characteristics of nanoadditive lubricant and its tribological behavior in the microextrusion process.

The Impact of Syringe Age Prior to Filling on Migration of Subvisible Silicone-Oil Particles into Drug Product

Silicone oil is often applied to the inner surface of glass syringes and cartridges to reduce friction between the glass surface and elastomeric plunger stopper. This oil can appear as intrinsic and non-proteinaceous particles in the ejected fluid or drug product. Limited data is available to understand the impact of age (time between syringe manufacture and filling) on silicone oil migration into the drug product. This study compares subvisible particle count and extrusion force of siliconized syringes from two different manufacturers stored at ambient condition for 2-3 (fresh syringes) and 13-14 (aged syringes) months then filled and placed at 40°C for an additional three months. The fresh syringes exhibit a 2.5-fold increase in subvisible particle count compared to those aged ones. Moreover, the fresh syringes exhibit up to a 2-fold increase in extrusion force. These findings suggest the degree and amount of silicone oil migration is influenced by the time in storage of the glass syringe prior to filling. This rapid communication highlights syringe storage time prior to filling as a factor to be considered during development.

Semi-analytical models for non-Newtonian fluids in tapered and cylindrical ducts, applied to the extrusion-based additive manufacturing

In this paper, mathematical models aiming at describing the fluid flow of non-Newtonian fluids inside ducts with both convergent and cylindrical sections have been formulated. The theory has been implemented for the description of industrially interesting fluids such as moisture-cured silicones and thermoplastics, which are well described by the Carreau and Cross-Williams-Landel-Ferry (Cross-WLF) rheological models, respectively. The viscous flow in a die has been considered, comparing the results with Computational Fluid Dynamics (CFD) solutions extracted through the Finite Element Method (FEM) software Comsol Multiphysics. The agreement with numerical data is very good, showing the potential for next experimental applications in predicting some very important and useful quantities, such as the extrusion force, which is critical for a wide range of 3D printing processes. The novelty relies in the general applicability of the theoretical models to viscous flows, no matter what its rheological behaviour is.

Conoid extrusion regulates glideosome assembly to control motility and invasion in Apicomplexa.

Members of Apicomplexa are defined by apical cytoskeletal structures and secretory organelles, tailored for motility, invasion and egress. Gliding is powered by actomyosin-dependent rearward translocation of apically secreted transmembrane adhesins. In the human parasite Toxoplasma gondii, the conoid, composed of tubulin fibres and preconoidal rings (PCRs), is a dynamic organelle of undefined function. Here, using ultrastructure expansion microscopy, we established that PCRs serve as a hub for glideosome components including Formin1. We also identified components of the PCRs conserved in Apicomplexa, Pcr4 and Pcr5, that contain B-box zinc-finger domains, assemble in heterodimer and are essential for the formation of the structure. The fitness conferring Pcr6 tethers the PCRs to the cone of tubulin fibres. F-actin produced by Formin1 is used by Myosin H to generate the force for conoid extrusion which directs the flux of F-actin to the pellicular space, serving as gatekeeper to control parasite motility.

Development of a new magnesium oxychloride cement board by recycling of waste wood, rice husk ash and flue gas desulfurization gypsum

Recycling construction waste wood to produce magnesium oxychloride cement board (MOCB) is an eco-friendly and high-value strategy. The effects of extrusion force, admixtures, wood fiber content and size on the physical and mechanical properties of MOCB were systematically investigated in this study. The results show that an appropriate increase in the wood fiber content in MOCB can not only reduce the density but also increase its flexural strength, but the pulling force decreases due to the reduction of compactness. Meanwhile, the small-sized wood fiber is beneficial to the increase of density and pulling force of MOCB, and the appropriate increase of wood fiber size can improve its flexural strength and water resistance. Increasing the extrusion force can also enhance the flexural strength and pulling force by increasing the compactness of the sample, but it is detrimental to the development of water resistance. Appropriate amount of rice husk ash (RHA) can improve the mechanical properties and water resistance of MOCB. The incorporation of flue gas desulfurization gypsum (FG) reduces the strength of MOCB, but its water resistance is improved. In addition, RHA and FG-modified MOCBs indicate better environmental benefits and performance indicators (Thickness swelling and water absorption) compared to conventional resin-based particleboard and Portland cement-based particleboard. This study provides not only strategies for recycling waste wood, but also technical parameters for producing eco-friendly cement composite boards.

Investigation of Cold Extrusion of Aluminum AA 2024 Alloy using Finite Element Analysis

In recent years, the interest in modeling extrusion processes has resulted in the development of several analytical and numerical methodologies. The present work optimizes cold extrusion process variables (Die angle (DA), Ram speed (RS), Coefficient of friction (CoF)) on extrusion force, displacement, damage and time for the Aluminum AA 2024 alloy material. DEFORMTM-3D software is used to carry out numerical simulations and to study the behavior of the Aluminum AA 2024 billet during the plastic deformation over the conical die. The die/ container and ram (top die) are considered as rigid bodies and the room temperature is maintained during the extrusion process. The simulations are conducted as per L27 Taguchi orthogonal array. The obtained results are analyzed in ANOVA. An optimization using multiple variables is performed by grey relational analysis (GRA). The highest grey relational grade (GRG) is obtained for experiments conducted at DA level 2, RS level 2, and CoF level 3 (minimum extrusion force, damage and time) and (maximum displacement) is achieved by GRA. Systematically, the influence of the ram speed, coefficient of friction, and die angle are examined. The damage factor is considerable at 30° DA under the ram speed of 3mm/min.

FEM simulation on forward extrusion of bi-metal rod

This study proposes FEM simulation on forward extrusion of bi-metal rod comprised of Aluminum (Core) and Copper (Sleeve). A Deform-2D commercial software with constant shear friction is used to explore the forming characteristics, such as the effective stress, the effective strain, the velocity field, the extrusion force, the die stress, the ratio of inner diameter to outer diameter at exit after the deformation (the aspect ratio). Besides the extrusion forces and the aspect ratio after the deformation obtained by FEM 2D can be compared with the upper bound method (UBM) and the experiment from Hwang [13]. It notes that the results are in a good agreement among three methods. Therefore the results from FEM 2D can be verified to be feasible from the experiment and UBM.

Numerical study of starch-gluten dough: Deformation and extrusion

Numerical investigation of starch-gluten model was conducted using composite micromechanics approach, which considered starch as circular filler embedded/surrounded by gluten matrix. The model developed was then compared with different starch-gluten models reported in literatures. The starch-gluten circular filler model simulations with different starch-filler diameters showed consistent results with the dough microstructure model, which suggested that the model can be used for dough process simulation, such as extrusion-based printing. Using similar approach, the extrusion model was then developed using billet representing starch-gluten dough being forced through the barrel with dies at different entry angles and ram extrusion speeds. Reducing the entry angles increased the extrusion force due to viscoelastic behaviour of dough. Likewise, a similar increased force results were obtained when the extrusion speeds were increased. • Starch-gluten model results is consistent with the dough microstructure model. • Extrusion speed and nozzle entry angle are important in dough 3D printing process. • The shape of different starch influenced the stress-strain behaviour of dough.