Metal Mold Research Articles

Investigation of properties of mortar containing pyrogenic silica-added supplementary cementitious materials

This study investigated the effect of supplementary cementitious materials (SCMs) with pozzolanic nature fly-ash (FA), silica fume (SF), and ground granulated blast furnace slag (GGBFS) on the properties of cement mortar with pyrogenic silica addition. First, standard reference (SR) samples were prepared using CEM I 42.5 R-type cement. Pyrogenic silica was added to cement (0.5% by weight) to prepare another group of reference (PR) mortar samples. Cement in PR mortars was replaced with FA, SF, and GGBFS up to 10, 20, and 30%. The mortar samples were placed in 40x40x160 mm metal molds using a vibrating table. The following day the samples were removed from the molds and water cured for 7, 28, and 90 days. The results showed that increases in curing times helped improve the mechanical properties of the mortars. Moreover, the physical properties of PR mortars were affected more positively than the SR mortars. SF-substituted mortars had highest compressive strength, followed by GGBFS- and FA- substituted mortars. In conclusion, pyrogenic silica contributed to some extent to early strength, followed by a decrease.

A study of process optimization of carburetor die casting process

Die-casting is a multipurpose practice for casting metallic components in high volume by pouring metal at high pressure into metal molds. In the present study, zinc based alloys having high ductility, impact strength and can be easily plated, are used to cast the carburetor. Zinc based alloys are also easy to cast, economical for small parts, good die life and low melting point. Defects arising in castings are mainly depends upon the solidification process and the intermediate temperature profiles, as the temperature gradients inside the casting will decide that a section in solidification stage has availability to necessary quantity of higher temperature molten metal. The consequences of die casting process parameters has not been deliberated widely to minimise the defects like tear out & misrun. The present work has been carried out to minimize the rejection rate due to these casting defects in die casting process of zinc alloy by adjusting parameters, molten metal temperature and time needed for solidification. During analyzing the previous data of production of castings, it was noticed that the Mixing Chamber Body of carburetors had a rejection rate of about 14–15%, but with the use of design of experiments using Taguchi method this rejection rate is reduced to 6.7%. ANOVA is used to specify the significant factors and solidification time has 92.5% contribution to minimize the defects. Confirmatory test performed at these optimal settings concluded that within 95% confidence interval casting defects were minimum. As the solidification time increases number of casting rejection rate decreases rapidly and at 6 s performed better result with lesser no. of defects and hence more effective.

Effect of different chloride environments on corrosion behavior of secondary AlSi7Mg0.6 cast alloy with higher Fe content

Secondary aluminum alloys are materials with higher Fe content. There are currently several studies on the corrosion behavior of casts from metal molds, but sand casts are being forgotten despite being still primarily used in gravity casting. Secondary Al-alloys have exceptional benefits as they are made from scrap and can be cast as thin-walled, which has a positive effect on the lightening of constructions, and on environmental impact. Unfortunately, the Fe is a common impurity but in higher content decrease properties of aluminum casts. The removal of the Fe content is very expensive, and therefore the effect of Fe content in a larger amount is monitored. This work is focused on the corrosion behavior of the heat-hardening aluminum alloys commonly used to produce castings AlSi7Mg0.6 for automotive. The experimental alloy was intentionally contaminated with Fe for reaching the critical amount of Fe in aluminum casts. Metallographic analysis (using optical and scanning electron microscopy, energy dispersive X-ray analysis) was used before corrosion tests. The microstructure of experimental alloys with higher content of Fe contains large Fe-rich phases in the form of needles. These changes in microstructure lead to the formation of a higher amount and size of porosity but the α-phase was not affected. Corrosion properties were examined by three basic corrosion tests: immersion test, potentiodynamic test, and Audi test. Corrosion characteristics of materials were evaluated using a stereo and optical microscope. Corrosion evaluation of the alloys shows the presence of pitting corrosion, which increases with increasing Fe content.

Influence of modification with highly dispersed silicon carbide on the casting properties of the secondary alloy of the Al-Si system

One of the main areas of application of aluminum is the aerospace and transport industries, which are constantly increasing the requirements for the properties of cast products. The use of aluminum as the main material for the manufacture of various parts of vehicles can significantly reduce their weight, which leads to a decrease in fuel consumption. In order to meet the requirements of the modern world, the work considers studies to improve the quality and increase the properties of products from the secondary aluminum alloy AlSi12. Modern technologies for processing liquid aluminum alloy are analyzed. According to the results of an analytical review, it was found that modifiers that affect the size of the primary grain and the shape of inclusions of eutectic silicon are of the greatest interest. It was found that the modification processes do not change the chemical composition of the alloy, but rather contribute to a change in the size and shape of the structural components of the alloy. The paper considers the influence of an ultradispersed SiC modifier with a particle size of up to 200 nm on the casting properties of secondary aluminum alloys: fluidity, linear and volumetric shrinkage. The fluidity was studied in green sand and metal mould. It was found that the addition of 0.1 % SiC improves the fluidity of the secondary alloy from 560 to 630 mm for green sand mould and from 230 to 295 mm for a metal mould due to cleaning from non-metallic inclusions. A further increase in the SiC content to 0.2 % does not lead to an obvious increase in fluidity. The study of linear shrinkage found that increasing the content of the modifier to 0.2 % contributes to its decrease. At the same time, an increase in the pouring temperature of the alloy promotes an increase in the total linear shrinkage, which is associated with the long residence time of the metal in the liquid state. As a result of the rapid crystallization of the melt with additional nucleation centers in the role of which are particles of the ultradispersed modifier, the coefficient of volumetric shrinkage decreases from 28 to 20 %. The proposed technical solutions for the modification of alloys of the secondary alloy AlSi12 can be used in processes that will improve the quality of cast metal products with the economical use of energy resources and materials for its production.

Analysis of Material Characteristics of Cast Metal Molds and Related Heat Treatment Process

This paper focuses on the analysis of the classification and characteristics of casting metal mold materials, and systematically studies the material heat treatment process and related processing technology of casting metal molds, providing horizontal reference for the integrative improvement of the thermal processing technology level of metal molds and the comprehensive utilization rate of metallic materials.

Study on metal/ceramics composite particle by the dry impact blending method for metal additive manufacturing

Metal matrix composites (MMCs) show a unique improvement in metal materials properties such as high specific strength enabling their use in various applications. Additive manufacturing (AM) allows production of complex or customized parts directly from the design without the need for expensive tooling or forms such metal molds and reduces the need for traditional MMCs processing method. Uniform mixed powder is important for producing MMCs. Although ball mills have been used in previous studies, there are problems with the length of the mixing time and the uniformity of the powder, and it is necessary to study the mixing method. Therefore, this study investigated the production of SUS316L/Al2O3 mixed powder for L-PBF using the dry impact blending method that is a method in which material powder is dispersed in a high-speed air flow and the powder is mixed by mechanical impact force. A composite powder was produced with a mixing time of 60-900 seconds for SUS316L powder weight : Al2O3 powder weight were 1 : 0.4 as a theoretical compounding weight and 1 : 0.4 as a theoretical compounding weight of 25%. As a result, it was found that a powder suitable for L-PBF with a single peak particle size distribution was produced in performed for 300 seconds or more with a theoretical composition of 25%.

Quantitative and qualitative surface analysis of three resin composites after polishing - An in vitro study.

Aim:The study aims to measure the surface roughness (Ra) of three resin composites subsequent to polishing with diamond-impregnated polishing paste.Materials and Methods:Sixty specimens (10 mm × 2 mm) were prepared in metal molds using three nanocomposites: GC Sculpt, Filtek Z350 XT, and Tetric N Ceram. Specimens were then subjected to baseline roughening with #600 grit sandpaper and were polished with DirectDia paste according to the manufacturer's instructions. After polishing, the Ra of resin composites of all the specimens was measured using profilometer and the surfaces were seen under scanning electron microscope.Results:Tetric N Ceram specimens were significantly smoother and had the least Ra value compared to other groups.Conclusion:Among the three resin composites tested, Tetric N Ceram exhibited the least Ra value owing to the small size of inorganic filler particles.

Formation of ideally ordered porous Ga oxide by anodization of pretextured Ga

An ideally ordered nanohole array of Ga oxide was formed by anodizing pretextured Ga. Prior to anodization, an ideally ordered array of concaves was formed on the Ga surface by nanoimprinting using a metal mold. The anodization of the pretextured Ga was carried out in a phosphoric acid solution. During anodization, each concave acted as a starting point of hole generation, resulting in the formation of the ideally ordered porous Ga oxide. The present process is expected to be applied to fabricate a light energy conversion device, such as a hydrogen formation device.

Analysis of the Influence of Boundary Condition on Simulation Accuracy of Solidification Thermokinetics Model

For a sample steel casting of a cylindrical shape that was cast in a metallic cylindrical mould, the analysis of influence and importance of the main boundary condition on the simulation accuracy of the temperature field in the system of casting-mould-environment was performed. For this system, the influence of the boundary condition on the frame of the mould, on the bottom of the mould, on the top of the casting, and on the casting-mould interface was analysed. As a comparing quantity for accuracy, the time-dependent temperature field (by means of isotherms) of the casting and of the mould and the total solidification time were selected. When the simulation considers the boundary conditions of one of these boundaries of the system, the heat transfer coefficient on the remaining three boundaries of the system is equal zero. The resultant heat flow along the axis is zero always. The conclusions can be used for fine-tuning of solidification models as well as for other applications; e.g. analysis and solution of inverse heat transfer problems.

Effect of Treated Zirconium Oxide (ZrO2) Nanoparticles on the Color and Surface Properties of Interim Fixed Prostheses.

ABSTRACTObjective:Zirconium oxide (ZrO2) nanoparticles addition to interim fixed prostheses (IFPs) was suggested to improve the mechanical properties. However, the effect of ZrO2 on the color and surface properties of IFP was neglected. Therefore, this study aimed to investigate the effect of ZrO2 on the color, hardness, and surface roughness of IFP.Materials and Methods:Customized split-press metal molds were used for the fabrication of forty disk-shaped acrylics (10 mm × 1.5 mm). The salinized ZrO2 particles were weighed using an electronic balance and added in concentrations of 1wt %, 2.5wt %, and 5wt % of auto-polymerized acrylic polymer powder. Based on ZrO2 concentrations, specimens were divided into one control group without ZrO2 and three ZrO2 study groups 1 ZrO2, 2.5 ZrO2, and 5 ZrO2, respectively. A double beam ultraviolet-visible reflection spectrophotometer was the instrument used for recording the color measurements (CIEDE2000). The Microhardness and surface roughness (Ra, μm) of all samples were tested. ANOVA test was used for data analysis (α = 0.05)Results:Notable changes were seen between the group containing 1% and the other two groups in Δa*, ΔΕab, and ΔΕ00 parameters. Statistically significant differences were observed among the three groups for the ΔL* parameter. No notable changes were seen between the group containing 1% and the group containing 5% for the Δb* parameter. The 1% group showed a statistically significant difference in hardness in comparison to the 5% group. For surface roughness, the 2.5% group presented statistically significant higher surface roughness as opposed to the 0% control group.Conclusions:The addition of ZrO2 in high concentrations resulted in a noticeable color change in IFP. However, the surface properties did not change hardness and roughness with ZrO2 addition except roughness increased with 2.5% ZrO2. Low ZrO2 addition did not result in a change in color and surface properties of IFP.

Comparative evaluation of net setting time and radiopacity in Fuji II (GC-Japan) restorative glass ionomer and Iranian glass ionomer

Comparing the net setting time and radiopacity of an Iranian glass ionomer cement (GIC) and Fuji II (GC, Japan) according to ISO 9917-1:2007 standard.In this experimental/in vitro study, for both tests, we prepared 20 samples of Fuji II glass ionomer (self-cure restorative glass ionomer, batch number: 1608031, GC Corporation, Tokyo, Japan) and Iranian glass ionomer (Ava Tajhiz Dandan-Iran) at P/L of 2/7:1. Then, to determine the net setting time, we prepared a metal mold with dimensions of 10 mm in length, 8 mm in width, and 5 mm in height. Ninety seconds after mixing, the surface of the sample was subjected to the indenter, and the net setting time was recorded as the time elapsed between the end of the mixing and the time needle stopped making a complete circular indentation. To determine radiopacity, the specimens were poured into a mold with a diameter of 15 mm and thickness of 1 mm. Samples and a step wedge were irradiated with X-rays. Particle size analysis and Energy-dispersive X-ray spectroscopy (EDS) analysis were also done for both cements. Test results were investigated with SPSS and through independent t-test (P < 0.05).The mean value of net setting time for Fuji II was 4.83 min and for the Iranian Glass ionomer was 3.83 min (P < 0.05). The mean value of radiopacity for Fuji II was 2.3 mmAL and for Iranian Glass ionomer was 1.9 mmAl (P < 0.05).Net setting time and radiopacity of the glass ionomers were within the range of ISO 9917-1:2007. If all properties of the Iranian cement are set appropriately in future investigations, we propose to use it instead of Fuji II GIC. This has the additional benefit of being cost-efficient as Iranian cement costs less than Fuji II cement.

Biodegradable polymers green synthesis of nanoparticle – An overview

Green nanotechnology disclosures can change over a wide scope of existing cycles and objects to work on ecological quality, work on the climate, and save the normal and non-renewable assets. Metal nanoparticles and nanocomposites are utilized in an assortment of synergist applications, hardware, science and clinical applications, material science, physical science, ecological remediation, and interdisciplinary fields, and their harmfulness is to a great extent dictated by underlying elements like size, shape, creation, and surface chemistry. Furthermore, it is basic to pick harmless to the ecosystem, nontoxic, and straightforward settling specialists and Functionalization pathways to expand the existence of metal nanoparticles and keep away from unfortunate impacts like accumulation in fluid arrangements and natural solvents, just as to stay away from ecological defilement and to reuse nanoparticles. Metal nanoparticles adjustment and surface Functionalization have become 'greener' lately, with biocompatible settling specialists, for instance, Biodegradable polymers and compounds, for instance, have been presented. These specialists had the option to make a wide scope of the especially stable circular, bar, and bloom molded metal nanoparticles, opening up additional opportunities for their application and large-scale manufacturing. The present status of the workmanship in the usage of biocompatible and biodegradable homo-and copolymers, just as compounds, to deliver stable, biologically harmless, particular, and dynamic metal nanoparticles for wanted applications is summed up in this review paper.

Preparation and Assessment of Antimicrobial Property of Resin Based Composites Impregnated with Proanthocyanidin and Titanium Dioxide

OBJECTIVE: To synthesize three experimental resin based composites (RBCs) out of a commercial preperation (Control) by impregnating into each a fixed weight (0.01%) of titanium dioxide (TiO2) and three different weight % (0.01, 0.02 and 0.03) of proanthocyanidin (PA) and to compare antibacterial property, from the zones of inhibition of streptococcus mutans (S. mutans), of the specimen restorations made in the experimental and control RBCs. METHODOLOGY: In the first phase, Streptococcus mutans were isolated and identified from the oral cavity of patients and identified on the basis of morphogenic appearance of colonies and confirmed through catalase test and microscopic examination. Isolates were then incubated and cultured for sensitivity. Specimens for control and experimental RBCs were made through a metallic mold having 2mm thickness and 5mm diameter for all the 4 groups. Specimen restorations made in the commercial as supplied RBC acted as the control (Group A). Specimen restorations in the Group B, C, and D were made in each of the experimental RBCs modified with 0.01% proanthocyanidin (PA) and 0.01% titanium dioxide (TiO2), 0.02% PA and 0.01% TiO2 and 0.03% PA and 0.01% TiO2. The antimicrobial property of all the specimen restorations in all the groups was evaluated by Bauer-Kirby (Disc Diffusion) method through the formation of zones of inhibition of S. mutans colonies on blood agar plates. Data were computed using SPSS version 21 for descriptive statistics and analyzed using one-way ANOVA with p value 0.05 taken as significant. RESULTS: The range of the zone of inhibition for specimen RBC restorations (N= 12) containing PA and TiO2 was 0.00 for Group A, 10-12mm for Group B, 12-14mm for Group C and 9-10mm for Group D. The mean inhibition zone for the experimental restoration specimens was 11±2mm for Group B, 12.7±1mm for Group C and 9.7±1mm for Group D compared to no inhibition zones (0.00 mm) with the control RBC Group A. The order of the inhibition zones from maximum to minimum was Group C &gt; Group B &gt; Group D &gt; Group A. The differences between the mean values for the control and the experimental RBC restoration specimens were significant (p &lt; 0.000). The specimen restorations in the Group D appeared under cured and could impact on their mechanical properties. CONCLUSION: Irrespective of the mentioned concentrations, impregnating PA and TiO2 rendered the RBC antimicrobial. RBC restorations made with the experimental RBC with 0.02% PA and 0.01% TiO2 proved relatively more effective in terms of antimicrobial effect. KEY WORDS: dental materials, resin based dental restorations, antibacterial resin based composite, proanthocyanidin, titanium dioxide.

Development of an Experimental Setup to Investigate Influences on Component Distortion in Gravity Die Casting and a First Variation of Temperature Control Strategy

Distortion (1), residual stresses and hot cracks can facilitate significant decreases in quality characteristics of casting products. Their reduction by a suitable component design (2) and process control is therefore desirable. In the casting process, these characteristics are assumed as a result of the combination of solidification shrinkage paired with the local self-feeding and the geometric constraints imposed on the component by the mold. In gravity die casting (3) of aluminum (4) with thermally well conducting and rigid metal molds, the control of solidification through a localized adjustment of the heat balance (5) appears to be a suitable approach to minimize these effects. The development of an experimental setup for the assessment of the interdependencies of the alloy, casting geometry and cooling are described in this work. A first series of experiments with A356 aluminum alloy and the introduction to the different methods of evaluation are presented. Furthermore, an approach to improve the understanding of the underlying mechanisms is outlined.

Anti-adherent Molds Yield Hydraulic Concrete Samples Suitable for Assessments of Surface and Water Absorption

To assess several quality parameters of hydraulic concrete, cubic samples of this material are commonly assembled in engineering laboratories using molds. It is ubiquitous the use of cubic metallic molds of volume 125 cm3; these molds require the application of demolding substances (such as oils) on their surfaces to avoid the adhesion of the final hardened concrete sample to the molds. Despite this common practice suitable for evaluating mechanical traits of the materials, the use of a demolding agent spoils the concrete samples for the assessment of surface and water absorption parameters. To overcome this difficulty, we propose a new anti-adherent cubic mold that requires no demolding agent. The construction of the new mold based on anti-adherent polytetrafluoroethene (PTFE, Teflon®) is described with its use. To assess the claimed advantages of the new anti-adherent molds in testing surface and water diffusion traits of concrete samples, experiments on water contact angles, rates of water absorption and drying were performed on concrete specimens obtained with the classic and the new PTFE molds. It was proved the advantage of the anti-adherent mold over common metallic molds. The use of an oil as demolding agent in the concrete samples assembled in metallic molds produced conspicuous differences of water contact angles and absorption in comparison to clean concrete samples produced with PTFE molds.

Thermal specification of 3D printed injection moulds made from PA12GB

This paper deals with the usage of the injection mould made from the plastic material. This technology is rapidly decreasing the time, necessary to the production of the prototype. This attribute takes nowadays a key role in the industry, especially in the automotive. Technology of using injection moulds from the plastic material (produced by additive technologies) has advantages in the decreasing of the time demands and cost reduction during the production of the prototype part. Unfortunately, plastic moulds have worse surface quality, lower lifetime of the mould (measured in number of produced parts) and more difficulties of moulding process regulation with respect to the metal moulds. This paper is focused on the injection process and it is describing the thermal distribution and specification of the comparable plastic specimen during injection into the metal and plastic mould. The results are the temperature and cycle-times comparisons. The effectivity of cooling is also compared in this work. It is obvious, that the plastic mould has worse results compared to the metal mould. However, this is clearly balanced by the speed of production and price of plastic mould. The prototype of the plastic mould was made from the material PA12GB with usage of 3D printer HP MJF4200

Epoxy tooling: Technologies, developments, sustainability and future interest to industry 4.0

The technology of epoxy tooling, at present under continuous development, is used for the rapid manufacture of cost-effective tools for small batch production. It is a valid alternative with no need for expensive investment in metallic moulds for the development of new products. Current investigations are focused on improvements to the production system, improved tool performance, the cost reduction of moulds and tool manufacturing sustainability. In this paper, both the advantages and the disadvantages of epoxy tooling in injection moulding, wax injection, metal stamping and hot embossing are compared with conventional techniques. Following a brief introduction of rapid tooling technologies, the latest advances of epoxy tooling and their implementation in different manufacturing processes are all analysed. These developments refer to the production of new ad-hoc epoxy composites, increased productivity using conformal cooling channels, the reduction of the tooling manufacturing costs through waste reuse and the emerging industry 4.0 technologies for smart manufacturing and tooling. The main objective is to identify both the challenges facing epoxy tooling techniques and future research directions.

Production injection moulds with additive technology by the HP MJF 4200 printer

This paper is focused on the production plastic parts. It is describing two technologies-injection moulding and additive technology. The production process of the metal mould for the new parts takes about ten weeks. It is necessary to make some reductions after the mould is produced. It is increasing the time which is necessary for the prototype of products. This time (from the initial design of mould to the prototype of product) can take about six months. Additive technologies can be used for decreasing this time and for cost reduction. Moulds produced by the additive technology are mostly special inserts which can be implemented in the universal design of mould. It is also possible to produce whole moulds from plastic material. These moulds can have integrated cooling channels. There are high demands on the material of the mould with respect to the thermal resistivity, toughness and surface quality. There are really often used SLA technologies, which are considering the High Temp Resin and Material Jetting Digital ABS. Other options used in the factories are Somos PerFORM and Digital ABS Plus. This paper deals with the possibility of usage of the HP Jet Fusion technology with the material PA12 GB for the production of mould inserts and it is evaluating this process and repeatability of process.

Preventing Accidental Overdoses by Innovating a Restrictive Prescription Pill Dispenser Vial (RPPDV)

Abstract: Rather than attempting to prevent all overdoses, the Prescription Pill Dispenser Vial (RPPDV) aims to prevent accidental overdoses by controlling how many pills a user can access within a twenty-four hour period. The RPPDV is much like a traditional pill vial. The body is similar to a conventional pill vial; however, it is modified to prevent the cap's opening without a special screw. The cap is heavily modified and uses a CR2032 or CR2025 coin cell battery to power a gate and the unlocking of the pill cap. The RPPDV works first when the user clicks the red button on the cap of the RPPDV, which opens the pill gate and opens space into a pill container section. This section is large enough for only one pill (or two if multiple pills are required simultaneously). Once a tablet has entered the pill container section, the button must be pressed again to close the pill gate. The user cannot open the lid to the pill container section until the pill gate is closed (see Fig 1.4.1). The RPPDV is similar to an escrow service, with the pill holder section acting as a middleman. The size of the pill holder container prevents access to multiple pills at the same time. The number of times the user presses the button is recorded and timed with a 555 timer set for twenty-four hours. For example, if a drug has a maximum dose of three pills per day, the button could be capped at four cycles or eight total pushes (to allow a grace cycle if a tablet is broken or stuck). Similarly, the gate cannot be opened unless the lid to the pill container section is closed. The production price of the RPPDV is significantly higher than a traditional pill vial and can get higher depending on the additional features added to the RPPDV. The necessary components to function include CR2032 or CR2025 lithium batteries, a 555 timer, and a coin battery holder, along with plastic and metal molds. The base model alone produces an estimated average cost per unit of $1.33 USD (see Fig 4.2.1). Additional features include adding a Bluetooth Low Energy (Bluetooth LE) component to customize the number of unlocks per day and RFIDs for storage and tracking. Prices vary depending on the specifications of the RPPDV.

Molds with Advanced Materials for Carbon Fiber Manufacturing with 3D Printing Technology.

Fused Deposition Modeling (FDM) 3D printing is the most widespread technology in additive manufacturing worldwide that thanks to its low costs, finished component applications, and the production process of other parts. The need for lighter and higher-performance components has led to an increased usage of polymeric matrix composites in many fields ranging from automotive to aerospace. The molds used to manufacture these components are made with different technologies, depending on the number of pieces to be made. Usually, they are fiberglass molds with a thin layer of gelcoat to lower the surface roughness and obtain a smooth final surface of the component. Alternatively, they are made from metal, thus making a single carbon fiber prototype very expensive due to the mold build. Making the mold using FDM technology can be a smart solution to reduce costs, but due to the layer deposition process, the roughness is quite high. The surface can be improved by reducing the layer height, but it is still not possible to reach the same degree of surface finish of metallic or gelcoat molds without the use of fillers. Thermoplastic polymers, also used in the FDM process, are generally soluble in specific solvents. This aspect can be exploited to perform chemical smoothing of the external surface of a component. The combination of FDM and chemical smoothing can be a solution to produce low-cost molds with a very good surface finish.