Vertical Mold Research Articles

Research on tracking and synchronization control of dual hydraulic cylinders based on improved active disturbance rejection control

To ensure the stability of vertical mold casting machine casting, and improve the quality of casting, for which the electro-hydraulic servo system of the traditional active disturbance rejection control(ADRC) of the nonlinear function is not smooth, a new type of nonlinear function is used. For the ADRC controller, there are too many adjustment parameters and complex engineering tuning, The snake optimization(SO) algorithm is used to adaptively tune the controller parameters, and the error can also be reduced. The simulation results show that compared with the PID controller and the traditional ADRC controller, the ADRC controller based on the Ifal function and SO has a certain jitter suppression effect as well as good tracking and synchronization performance, which can effectively improve the tracking and synchronization accuracy of the dual hydraulic cylinders of the electro-hydraulic servo system.

Numerical Simulation of Flow, Heat, Solidification, Solute Transfer and Electromagnetic Field for Vertical Mold and Curved Mold of Billet

Numerical Simulation of Flow, Heat, Solidification, Solute Transfer and Electromagnetic Field for Vertical Mold and Curved Mold of Billet

The unearthed bronze coin molds and the evolution of coin technology in the Warring States period and Qin-Han dynasties

Abstract Coin-minting models and molds can be classified into grand master patterns, master patterns, and casting molds, based on function. The archaeological data available at present show that the bronze coin molds are mainly master patterns and casting molds. This paper makes an as complete as possible collection of archaeologically unearthed bronze molds from the Warring States period to the Qin-Han dynasty, and then classifies them based on coin-minting technology and their functions and forms. After that, the ways to make the molds and to use them to mint coins, as well as the development procedure from vertical mold assembly technology to stack-casting technology are observed. Finally, the social background of the evolution of the coin-minting technology in this period is discussed.

Numerical simulation of vertical mold casting temperature field of copper anode plates

As an important raw material for refining copper by electrolysis, copper anode plates are mainly manufactured by disc casting machine. However, those copper anode plates frequently have such defects as uneven thickness, broken lugs, porosity inside plates, and low production efficiency and low yield rate, failing to meet the demands of electrolysis for the quality and quantity of anode plates. To develop a new vertical mold casting process for copper anode plates and study the influence of cooling on the life of the machine during vertical mold casting, two design schemes of cooling channels for the high-temperature working mode of copper anode plate production were put forward in this paper, and ANSYS was introduced to simulate and analyze the flow state, flow rate and temperature field of the cooling water. The results indicated that the vertical mold with the double-cycle cooling channel is about 2 °C lower than that with the single-cycle cooling channel. The temperature of the former at point A outside and point B near the lug inside the vertical mold is 20 °C–30 °C higher than that of the latter. The temperature of vertical mold casting copper anode plates with double-cycle cooling channel is below 700 °C when casting for 50 s, suggesting that the copper anode plates have more uniform temperature and higher cooling efficiency with the double-cycle cooling channel, which can prolong the service life of the casting machine. The research results lay a theoretical foundation for the manufacture of copper anode plates and the improved design of the copper vertical mold casting machine.

Determination of optimised solvent debinding parameters of injection moulded 316L stainless steel using Taguchi approach

Abstract Metal Injection Moulding (MIM) is widely utilized in various manufacturing industries due to its ability to produce near net shaped components in high volume without compromising surface finish and mechanical properties. Debinding is one of the most crucial phases in the MIM process, as it affects the final properties of the end product. The use of 316L SS is widespread especially in the medical industry, specifically for implants and metallic biomaterials due to its favourable combination of mechanical properties and biological consistency The present work deals with utilization of the Taguchi method to investigate the influence of solvent debinding parameters on the characteristics of injection moulded 316L stainless steel (316L SS) using thermoplastic rice starch binder as one of the binder components. In this study, the 316L SS powder along with a binder system consisting of Thermoplastic Rice Starch (TPRS), Polyethylene (PE), Palm Stearin (PS) and Stearic Acid (SA) were mixed for 1 hour at a speed of 50 rev/min and at a temperature of 150°C using a Z-blade mixer. The feedstock was then injection moulded using a vertical injection moulding machine with parameters of injection pressure, injection temperature and time and holding time of 7 bar, 160°C, 10 seconds and 25 seconds respectively. , this research was done utilizing the Taguchi approach to investigate the influence of solvent debinding parameters of injection molded 316L SS The effects of three solvent debinding parameters: solvent type, debinding time and debinding temperature were investigated to obtain the highest percentage of binder removal. The interactions of the parameters were laid out using the L 9 orthogonal array. It was found through ANOVA that solvent type had the most significant effects on solvent debinding, followed by debinding temperature and debinding time. The optimized solvent debinding parameters are solvent type of methanol, debinding temperature of 80°C and debinding time of 4 hours. The confirmation experiment however did not achieve the required range of expected result with a 3.80% error due to the unstable behaviour of the optimized solvent type, methanol.

Solidification of subcooled gallium poured into a vertical cylindrical mold

The present investigation is aimed at the solidification of subcooled liquid gallium. The gallium, in its liquid state, is contained in a cylindrical shell of copper or polypropylene, and poured into the shell, which is immersed in a cold bath. The experimental degree of subcooling varied between 5°C and 45°C. The phenomena empirically observed have been simulated in four stages: subcooling of the liquid gallium down to its nucleation temperature, a rapid transfer from nucleation to the stable solidification temperature, stable solidification up to its completion and finally cooling down of the solid gallium. The conductivity of the sample shell affects the length of each stage. In the copper shell the sample loses up to 5% of its released heat along the second stage. In the polypropylene shell, the sample does not lose any heat in that stage. The entire process for initially contained liquid gallium is analyzed by formulation of heat transfer rates at each stage. The only empirical figure used in the analysis is the nucleation temperature. Matlab software is used to solve the formulations. The model presents time-dependent temperatures and melt fraction. The model agrees well with the experiments. For the flowing liquid gallium, the rate was 0.12 - 0.3 ml/s. The numerical study explored solidification of the flow of liquid gallium by a two-dimensional (axially symmetric) model, using Fluent 6.2 software. Previous investigations in our laboratory, using other flowing phase-change materials, have demonstrated that the solidified phase at the cooled boundaries adheres to the walls with irregular cavities. In the present study the flowing and solidifying gallium has formed an irregular boundary at the walls, too. However, the numerical model has closely predicted the entire process of solidification and cooling of the solid. At higher flow rates the solidification approached the behavior of a static liquid gallium.

Effect of Mold Fixture on Stress and Deformation of Composite Structures

During the process of autoclave formation of thermosetting composite structures, the temperature distribution is strongly influenced by the forming fixture, which then contributes to forming error of the composite structure. On the base of 3D thermomechanical model by the software ABAQUS effects of mold fixture on temperature, stress and deformation are investigated. Numerical simulation results of the composite structure show that the deformation in the two sides and stress in the middle are both maximum. Comparison of composite structures shows that the column mold fixture, in contrast to oblique support mold and vertical plate mold ones, manifests uniform temperature and deformation distributions during the process of autoclave formation. Therefore, from the viewpoint of controlling the deformation of the composite structure, the column mold fixture is superior to the oblique support or vertical plate mold fixtures.

Effect of Rotational Speeds on the Cast Tube During Vertical Centrifugal Casting Process on Appearance, Microstructure, and Hardness Behavior for Al-2Si Alloy

The flow of molten metal plays a crucial role in determining casting quality. During rotation of the mold, melt flow around its inner circumference determines the final configurations and properties of the cast tube. In this paper, Al-2Si alloy is cast in the vertical mold at the various rotational speeds of the mold. The uniform cylinder tube is formed at a rotational speed of 1000 rpm, while before and beyond this speed, irregular-shaped cast tube is formed. Finally, fine structured grain size with high hardness value is found in uniform cast tube compared with others.

Fluidity Test of Al-Si Alloy Using by Computer Simulation

Fluidity is the basic foundry property. The fluidity of AlSi alloy in real condition with computer simulation were compared. In this test was used two types of molds: horizontal molds with tree canals and vertical molds with six canals wich had different diameter (4,5; 6,5; 8,5; 10,5; 12 and 14 mm). As experimental material was used AlSi10MgMn (EN 1706) alloy. Range of pouring temperature was between 605°C to 830°C. NovaFlow&Solid soft commercial software package was used for numerically simulating the fluid flow of molten metal. The model of fluidity test was created by CAD system CATIA V5 R19. Measurement systems analysis (MSA), the analysis of the variance (ANOVA), t-test and the analysis of correlation were used for the evaluation. Youden plot was used for evaluation of the impact of operators on the errors. Values of fluidity for each temperature level obtained by the horizontal mold have a high degree of agreement with those obtained by computer simulation. On the contrary, the values, obtained by the vertical mold are more sensitive to the operator. This fact caused the match between the simulation and a practical experiment is only partial.

Influence of Casting Direction on the Mechanical Properties of Cementitious Fiber Reinforced Composites

This paper is focused on behavior of fiber reinforced cement composites (FRC) and ultrahigh-performance fiber reinforced cement composites (UHPFRC) in dependence on the direction of casting. Almost fifty prismatic samples of size of 400 x 100 x 100 mm were cast into horizontal and vertical moulds. Forty of them with most corresponding results were used in this paper – twenty for FRC and twenty for UHPFRC. In each mixture three samples of both series were cast in the common horizontal direction and the other three in the vertical way. It was found that specific fracture energy of horizontally cast prisms was approximately four and half times higher for both materials than the vertically cast ones. The peak loads of FRC were very similar for both ways of casting. On the other hand the UHPFRC behaved differently, the peak load of horizontally cast prisms was approximately three times higher than the vertically cast ones. It was demonstrated that these differences are caused by the way of casting and vibration.

Investigation of Biomechanical and Biosafety of Injection Moulded Implant Materials

This paper presents the attempt to manufacture metallic implant using medical grade 316L stainless steel alloy powder by MIM process. The powder with the median particle size of 15 μm and a binder consisting of palm stearin and poly ethylene were mixed at 160°C using a sigma-blade mixer for one hour to prepare the feedstock of the test bar. The rheological properties of the feedstock was tested using capillary rheometer. The test bar was injection moulded using vertical injection moulding machine with the nozzle temperature of 200°C. Prior to sintering, the specimens were debound using a combination of solvent extraction and thermal pyrolysis method. The specimens were then sintered under vacuum at the temperature between 1300oC to 1360oC. The properties of the sintered bar such as physical appearance and densities were presented and discussed. The biocompatibility including toxicity properties of the implant also been presented. The results showed that physical and mechanical properties of the sintered sample complied with the international standard

Production of 415-ton ingots for backup rolls in the conditions of PJSC 'Energomashspetsstal'

The paper gives the results of work on melting, pouring, forging and heat treatment of 415-ton 45H3M1F steel ingots as semiproducts for manufacturing large backup rolls at the request of 'Severstal' Company. For the production of rollers, a new grade of steel based on 0.45%C and 3%Cr, additionally alloyed by Mo and V, was developed in PJSC 'Energomashspetsstal' and applied in industry. Steel of bainite class provides the best combination of strength and plasticity properties. Metal was prepared by melting 7 heats in arc steel-melting furnaces with the capacity of 100 and 50 tons with subsequent out-of-furnace treatment on ladle - furnace and ladle - degassing units. The pouring of steel was carried out from four steel-pouring ladles into a vertical mould under vacuum through a tundish ladle with the protection of stream by argon. The forging of ingots was conducted on the automated 150MN forging system. The obtained billets were exposed to primary heat treatment which consisted of heating for recrystallization, isothermal soaking, in order to provide the removal of residual stresses, additional dehydrogenization to give the material lower hardness and controlled cooling for the prevention of snowflake formation. Heating of ingots for forging and preliminary heat treatment was carried out in heat treatment furnaces with the carrying capacity of up to 500 tons. For the heat treatment of the backup roll, a horizontal sprayer unit was applied. The tooling of the backup roll was executed on a lathe with one pace-plate and the final mechanical treatment was conducted on the machine-tool of Hercules NWD 1500×18000 CNC. Finished products with 225-ton mass of the following dimensions: a barrel with a diameter and a length of 2,360 mm and 4,800 mm, respectively, at a general length of 10,650 mm were obtained.

Lab experiments on the innovative rapid thick strip casting process

Rapid thick strip casting (RTSC) by Anton Hulek, Inventmetall®, is an innovative concept for the production of hot strips with a final as-cast thickness of about 25 mm before rolling. The innovation of the mechanism consists in a vertical mould performing a caterpillar motion. This moving mould has an unconventional parallelogram-shaped cross-section. The conventional rectangular shape is formed in the shaping machine, which is placed straight below the mould. Further elements of the technology are state-of-the-art. For the investigation of this new casting system theoretical calculations were complemented with practical experiments. The investigation focused mainly on two key aspects: the characteristics of the mould and the shaping process. For the practical analysis a static mould with three pairs of elements in laboratory scale was developed and commissioned by the Dept. of Ferrous Metallurgy @ RWTH Aachen University. The shaping experiments were carried out in model scale with two different materials and in variable boundary conditions. The results of these experiments delivered important mechanical as well as thermal informations about the casting system.

Induction Steel: Inclusion Content and Mechanical Properties of Reinforcing Bars Produced from Pencil Ingots and Continuously Cast Billets

In Bangladesh, most of the reinforcing bars are produced by rolling steel produced by melting scrap in induction furnaces. In many plants the molten steel is directly cast in vertical moulds into what are usually called ‘pencil ingots’. In some plants the molten steel is tapped into large ladles, taken to continuous casting machines and cast into continuous billets. In some cases the molten steel is refined in ladles (purged with nitrogen or argon) before casting into continuous billets. This investigation aims at a comparison of the inclusion content and resultant mechanical properties of reinforcing bars produced through these different routes. The samples for this study were collected from the process streams of a steel plant. The inclusion content was determined by direct measurement of inclusions on metallographic specimens and the mechanical properties were determined by using a universal tensile testing machine. Reinforcing bars produced by rolling ladle refined continuously cast billets have the lowest content of inclusion and the best mechanical (yield strength, ultimate tensile strength, percentage elongation, etc.) properties. The highest inclusion content and the worst properties were obtained in the pencil ingots.

Fabrication of 2D silicon nano-mold based on sidewall transfer

A method based on the sidewall transfer technique for fabricating two-dimensional (2D) nano-mold on a silicon substrate was developed. Instead of using expensive nanolithography, the authors fabricated 2D silicon nano-mold using standard ultraviolet lithography, conformal deposition of gold by radio frequency sputtering, argon sputter etching and deep reactive ion etching (DRIE). This technique enables the generation of very fine geometries with nanoscale dimensions without the electron-beam (e-beam) lithography equipment or other additional lithography techniques. Based on SF 6 , O 2 and C 4 F 8 plasmas, a vertical mold profile and a minimum scallop size of 30 nm were obtained by optimising DRIE parameters. For smooth mold surfaces, the authors report and demonstrate a new mechanism of removing grass obtained during inductively coupled plasma etching. With this technique, very uniform 2D silicon nano-molds consisting of 200 nm wide, 200 nm high and 4.3 mm long bar arrays have been successfully fabricated.

The Effects of Nodularity Distribution on Vertical Configuration Mould for Automotive Ductile Iron Casting

Mechanical properties of ductile iron casting are strongly inclined with metal matrix microstructure, graphite elements presence and impurities rate. Increasing in the number of graphite elements near to sphere shape (nodule), more superior mechanical properties will be realized. Automotive castings normally produced in mass production due to high demand; vertical moulding configuration is one of the best options for producing mass quantity automotive castings. This study aim to discover either the vertical moulding configuration will affects the nodularity properties distribution for different cavity position in the mold. In this study, ductile iron disc brake castings have been produced by in-mold Mg treatment using vertical parted molding method. Samples from different cavity position were taken and analyzed their nodularity distribution. Image processing computer procedure-Lieca was used to characterize the graphite morphology of the samples. The result shows that the different cavity position of vertical orientation disc brake casting produced dissimilar distribution of graphite. Higher position of cavity has higher nodule count and round graphite.

Effects of Mold Side Wall Profile on Demolding Characteristics

Silicon molds with various taper angles are fabricated and demolding forces are examined for the thermal imprinting of poly(methyl methacrylate) (PMMA) films on a silicon substrate. The silicon mold patterns are fabricated by a switching process, which consists of sequentially alternating etching and deposition steps. The side wall angle of mold trenches is controlled by adjusting deposition step time. The demolding force for the vertical mold is 0.35 MPa. The demolding forces for the inverse taper mold angle (taper angle, 92°) and the normal taper angle (taper angle, 83°) are 1.0 and 0.2 MPa, respectively. The residual PMMA thickness is not uniform. The surface profile of the PMMA film is also curved. Both the nonuniform residual PMMA thickness and the curved profile of the PMMA surface are caused by silicon wafer deformation. It is confirmed that the variation of PMMA surface height is proportional to the residual resist thickness.

Spatial variation of heat flux at the metal–mold interface due to mold filling effects in gravity die-casting

Most of the research work pertaining to metal–mold heat transfer in casting solidification either assumes no spatial variation in the air gap formation or limits the study to only those experimental systems in which air gap formation is uniform. However, in gravity die-casting, filling effects induce variation in thermal field in the mold and casting regions. In this paper, we show that this thermal field variation greatly influences the time of air gap initiation along a vertical mold wall, which subsequently leads to the spatial variation of air gap and in turn, the heat flux at the metal–mold interface. In order to study the spatial variation of heat flux at the metal–mold interface, an experimental setup that involved mold filling was devised. A Serial-IHCP (inverse heat conduction problem) algorithm was used to estimate the multiple heat flux transients along the metal–mold interface. The analysis indicates that the fluxes at different mold segments (bottom, middle, and top) of the metal–mold interface reaches the peak value at different time steps, which shows that the initiation of air gap differs along the mold wall. The experimental and numerical results show that the heat transfer in the mold is two-dimensional during the entire period of phase change, which is initially caused by the filling effects and further enhanced by the spatial variation of the air gap at the metal–mold interface.

Estudio de la resistencia a la tracción y deformación de fundición esferoidal de pequeño espesor

El presente trabajo analiza las propiedades mecánicas de placas de fundición nodular con espesores que varían entre 1.5 y 4 mm, coladas en moldes de arena con modelos de disposición vertical y horizontal. Se realizaron coladas con distintos carbonos equivalentes, obteniéndose conteos nodulares en el rango de 900 a 2200 nod/mm2. Todas las probetas ensayadas fueron sometidas previamente a un tratamiento de ferritizado, a fin de evitar la influencia de los distintos microconstituyentes. Se obtuvieron resultados de alargamiento a la rotura que superan lo estipulado por la norma ASTM A536, lográndose valores de hasta 32%, en placas de 4 mm de espesor coladas en molde vertical. Se establecieron las influencias que el Carbono Equivalente (CE), el conteo nodular y la composición química ejercen sobre las propiedades mecánicas.

Gating system design to cast thin wall ductile iron plates

The present study describes the development of a horizontal and a vertical mould designed to produce thin ductile iron plates of 1·5–4 mm thickness. Both moulds used a non-pressurised configuration. The horizontal mould design was based on empirical rules, while the vertical mould was based on numerical simulations of fluid flow and thermal field, carried out using the software NovaFlow&Solid. The aim of both designs was to produce sound ductile iron plates that were large enough to make tensile test samples. The results show that the adoption of empirical rules and a non-pressurised configuration were not enough to guarantee proper filling. An optimised design was obtained through the use of mathematical modelling.