Gating System Research Articles

Reliability and properties enhancement of as-cast aluminum alloy through gating system design

In this work, the influence of temperature on fluidity and gating system design on the physical, and mechanical properties of as-cast AA6063-T6 aluminum alloy have been examined. The pouring temperature has been used as a controlling parameter for flowability measurement and a spiral ceramic placed in a sand mold for measuring the fluidity index of the molten alloy. A linear relationship between the casting temperature and the fluidity length was observed. These show that fluidity increases linearly with the pouring temperature. Also, an expanding systems and pressurized gating systems were experimented through sprue-runner to cross-sectional area variation. The ultimate tensile strength of the samples was not significantly affected by the in-gate system design. Meanwhile, the fracture elongation seemed to be more dependent on the melt quality than on the in-gate system design. The true stress-strain graph indicates that expanding systems are better than pressurized systems. The plot of residual against fit for regression analysis does not show random distribution about the reference point.

Calculating method of gating system parameters during die casting of thermoplastic slips for MIM-technology

Method for calculating of the die casting parameters system of a thermoplastic slip for MIM-technology is described. Three main elements of the system are considered: the central gate, the spreading channels, the intake gate. A method of analogies for choosing of the location of the supply of a thermoplastic slip to the casting is proposed.

Lean Implementation Framework: A Case of Performance Improvement of Casting Process

Globalization breeds increasing competition. In today’s dynamic climate, lean thinking has been found a promising business continuous improvement strategy for improving quality while reducing product cost and delivery time. However, its implementation has dynamic nature of challenges that varies from industry to industry and country to country, necessitating a specific framework by taking all stakeholders onboard. This study aims to propose a lean implementation framework to reduce defects and waste to improve the performance of the metal casting industry. The structure of the framework has been divided into three phases namely the lean conception phase, lean implementation phase, and lean sustainability phase. The proposed framework integrates the six sigma DMAIC methodology with lean tools and techniques to reduce defects and achieve performance improvement. A solid cast software has been used as a computer-assisted casting simulation tool to perform the analysis of defects within the casting. Further, the proposed framework is demonstrated and validated by employing a real-time case study that was manufactured using the sand casting process. The obtained results show remarkable improvements in poured metal weight (33.3%), mold weight including gating system (40%), casting yield (24.56%, rejection rate (90%), and financial saving (24.63%). As a result of analysis of percentage improvements data, the proposed framework can provide the practitioners with a standard roadmap and motivate the casting industries to implement lean for performance improvement through organizational change. Through the effective application of the lean implementation framework, quality enhancement has been demonstrated.

Performance prediction of magnetorheological fluid‐based liquid gating membrane by kriging machine learning method

AbstractA smart liquid gating membrane is a responsive structural material as a pressure‐driven system that consists of solid membrane and dynamic liquid, responding to the external field. An accurate prediction of rheological and mechanical properties is important for the designs of liquid gating membranes for various applications. However, high predicted accuracy by the traditional sequential method requires a large amount of experimental data, which is not practical in some situations. To conquer these problems, artificial intelligence has promoted the rapid development of material science in recent years, bringing hope to solve these challenges. Here we propose a Kriging machine learning model with an active candidate region, which can be smartly updated by an expected improvement probability method to increase the local accuracy near the most sensitive search region, to predict the mechanical and rheological performance of liquid gating system with an active minimal size of experimental data. Besides this, this new machine learning model can instruct our experiments with optimal size. The methods are then verified by liquid gating membrane with magnetorheological fluids, which would be of wide interest for the design of potential liquid gating applications in drug release, microfluidic logic, dynamic fluid control, and beyond.

Design of gating system for propeller casting through melt flow simulation

Design of gating system for propeller casting through melt flow simulation

Effect of feed elements of gating system on oxide spots contamination of chill aluminum castings

The effect of the feed elements of the gating system on filling rate of chill mould by the aluminum alloy is considered. An additional element of the gating system is proposed to ensure the required change in the melt rate in the feeder and to limit the flow of the first portions of the melt most contaminated by oxides into the forming cavity. The regularities of the effect of the gating system design on the maximum melt rate in the feeder, the technological yield of the suitable and the contamination of the casting by oxides are established. The area of rational use of conical funnels is shown. The use of more metal-intensive oval funnels and bowls is justified for complex geometry castings, which can create conditions for the melt to spread over the developed surfaces of the mould and, consequently, the intensive course of oxidative processes during the filling of the chill mould cavity or having a mass of 1.5 kg and above.

Design of gating system for propeller casting through melt flow simulation

Design of gating system for propeller casting through melt flow simulation

Simulation and experimental analysis of re-design the faulty position of the riser to minimize shrinkage porosity defect in sand cast sprocket gear

Shrinkage porosity is known to occur when feeding is cut off due to several reasons that can cause an early solidification of the molten metal on the riser affecting the overall feeding process. Casting simulations can give a clear understanding of determining the existence of shrinkage porosity by considering variable process parameters like the improper design of a riser and faulty positioning of the riser. This research work aims to investigate and minimize the occurrence of the open shrinkage porosity resting on a sprocket gear made of Carbon steel Material. The design of the gating system was done using Modulus Methods, and 3D Model was prepared by using CATIA software. The optimization of the feeding and gating system is conducted using PROCAST software, taking into account the actual casting data from the foundry and the experiment was conducted to validate the simulation results. The analysis of PROCAST predicts that the position and feed volume of riser is the key factor for sound casting by showing porosity concentration is less and casting experimental result validates the increase weight final casting than earlier. An improvement in the overall quality of the product was observed when compared to sprocket gears produced in the foundry before.

NUMERICAL ANALYSIS OF INFUSION STRATEGIES IN VACUUM ASSISTED RESIN TRANSFER MOLDING (VARTM) PROCESS

The Liquid composite Molding (LCM) process, such as Vacuum Assisted Resin Transfer Molding (VARTM), offers a fast and high-quality production of composites laminates. In the VARTM process, the simulation tool is found beneficial to predict and solve composite manufacturing issues. The part quality is dependent on the resin mold filling stage in the VARTM process. The infiltration of resin into a porous fibrous medium is taken place during the resin mold filling stage. The permeability has a crucial role during the resin mold filling stage. In this study, simulation of resin infusion through multiple injection gates is discussed. The various infusion schemes are simulated to identify defect-free composite manufacturing. The simulation approach is applied to five different stacking sequences of reinforcements. In this transient simulation study, permeability and resin viscosity is essential inputs for the resin flow. The simulation approach found that a gating scheme plays a vital role in mold filling time and defect-free composite fabrication. It is found that the line gating system can be useful for fast mold filling over the point gating system.

Design and Prototyping of Electronic Load Controller for Pico Hydropower System

A hydroelectric power plant is an electrical energy generator that utilizes water energy to drive a water turbine coupled to a generator. The main problem in hydroelectric power plants is the frequency and voltage fluctuations in the generator due to fluctuations in consumer loads. The purpose of this research is to make a prototype of the Electronic Load Controller (ELC) system at the Pico Hydropower Plant. The main part of ELC is the frequency sensor and gating system. The first part is made by a Zero Crossing Detector, which detects the generator frequency. The gating system was developed with TRIAC. The method used is the addition of a complement load which is controlled by delaying the TRIAC. Load control is intended to maintain the stability of the electrical energy produced by the generator. The PID algorithm is used in frequency control. The results of the frequency sensor accuracy test are 99.78%, and the precision is 99.99%. The ELC system can adjust the frequency automatically by setting the firing delay on the TRIAC to distribute unused power by consumer loads to complementary loads so that the load used remains stable. The ELC is tested with increasing and decreasing load. The proposed ELC gives a stable frequency at 50Hz. Whereas at the first test, the mean voltage is 183V, and in the second test is 182.17V.

Analysis of Causes of Porosity Change of Castings under the Influence of Variable Biscuit Height in the Filling Chamber.

Quality properties of castings produced in a die casting process correlate with porosity that is conditioned by a number of factors, which range from input melt quality to setup of technological factors of the die casting, and through structural design of the gating system. One of the primary parameters conditioning the inner soundness of the casting is the liquid metal dose per single operation of die casting. This paper examines the issue of metal dose. The experiments are performed with casting a gate system of an electromotor flange. The gating system examined was die cast with a variable volume of metal dose per single operation. The metal dose was adjusted to reach the height of a biscuit of 10, 20, and 30 mm. The examination of the inner homogeneity of the castings of the individual variants of gating systems with variable height of the biscuit proved that decreasing biscuit height results in an increase of porosity share in the casting volume. The programme MagmaSoft 5.4 revealed the main causes of changes in porosity share. The simulations detected that the change in biscuit height and volume of liquid metal directly influence thermal conditions of the melt in the filling chamber, and in the mould by means of the period in which the holding pressure action is influenced. Simultaneously, the melt flow mode in the sprues and gas entrapment in the melt volume are affected as well. Correlation of the factors consequently influences the final porosity of castings.

Assessment of the suitability of a gate design modification compared to the change in pressing velocity considering the distribution of gases in the casting volume

The qualitative properties of high pressure die castings are closely correlated with their internal structure, which is directly conditioned by the gas entrapment in the melt volume during the casting cycle. It is known that the gas entrapment in the volume of the melt and their subsequent distribution into the cast can be reduced by changing the technological parameters of the casting cycle or by the modification of the gating system design. The contribution addresses the issue of which variant of the gas content reduction is more efficient regarding the gas entrapment and the nature of the melt flow in the runners. The experiments are based on a real casting process. The established design solution of the gating system and the technological parameters setting are considered as a referential. Different gating system modifications were designed where the design modification is connected with the cross-section of a gate, in which the final acceleration of the melt flow occurs. The observed melt velocity in the gate is considered as a correlation factor, based on which the modification in the piston velocity is determined. The assessed parameter is the gas entrapment in the cast volume at the end of the filling phase. Assessment of the casting cycle and evaluation of experiments is performed using simulation program Magmasoft. Based on the performed analyses, it can be stated that the gate design modification will affect the filling regime of the die cavity by changing the melt velocity in gate, but the nature of the melt flow in runners remains unchanged. Modification of the piston velocity affects the filling regime of the die cavity, and also the nature of the melt flow as it passes through the runners, thereby promoting the gas entrapment in the melt volume. Therefore, it is necessary to pay an increased attention to the design of the gating system and only after debugging the design to proceed to the optimization of technological parameters.

Numerical Simulation and Experimental Validation of Melt Flow in the Naturally Pressurized Gating System

The main problem during the production of castings from aluminium alloys is the presence of the reoxidation, which negatively affects the final casting quality. Liquid metal surface reacts with the surrounding atmosphere and oxide layer of Al2O3 is formed on its surface. The problem occurs when the oxide layer is entrained to the internal volume of the melt by turbulence and double oxide layers are formed, also known as “bifilms”. Its formation is related to the melt velocity and gating system design. In paper, naturally pressurized gating system was calculated and designed. Effect of the filter media and vortex element on the melt velocity, amount of oxides, mechanical properties, and porosity were observed. Designs with 10 ppi and 20 ppi foam filters and vortex element were compared with design without filters to prove the positive (or negative) effect of filter media on melt velocity and thus on final casting quality. The melt velocity and amount of oxides were observed with the aid of simulation software. Mechanical properties, quantity of pores, bifilm index and EDX analysis were evaluated after experimental casts. It was proven that by using 20 ppi foam filter in combination with vortex element, the best results were achieved.

Performance Evaluation of Visual Guidance Patient-Controlled Respiratory Gating System for Respiratory-Gated Magnetic-Resonance Image-Guided Radiation Therapy

To evaluate the performance of visual guidance patient-controlled (VG-PC) respiratory gating system for respiratory-gated magnetic-resonance image-guided radiation therapy (MR-IGRT) and to investigate the relationship between patient specific factors and the performance of the system.The VG-PC respiratory gating system consists of a beam projector in the treatment room to project the near-real-time cine planar MR images inside the bore of the system in order for patients to monitor the images during treatment. With the visual information, patients voluntarily control their respiration to put the target volume into the gating boundary (gating window). A total of 15 patients with lung or liver tumors who were scheduled for stereotactic ablative radiotherapy (SABR) were selected for the study. A comprehensive instruction about the VG-PC gating system was given to patients before the first treatment. Some of the fractions were treated with the respiratory-gated MR-IGRT combined with the VG-PC gating system, while the remainder of the treatment was performed without the VG-PC gating system (free-breathing). For each fraction the total treatment time, beam-off time owing to the respiratory gating, and number of beam-off events during whole treatment session were analyzed.The average beam-off times due to respiratory gating with and without the VG-PC gating system were 806.0 ± 531.46 s and 1163.7 ± 773.9 s respectively (P < 0.05). Consequently, the average total treatment time was reduced from 2033.5 ± 928.0 s to 1674.7 ± 727.7 s by using the VG-PC gating system (P < 0.05). The average number of beam-off events during whole treatment session was reduced from 395 ± 213 times to 196 ± 127 times by using the VG-PC gating system (P < 0.001). The percent decrease in the average beam-off times due to respiratory gating, the average total treatment time, and the average number of beam-off events for patients with lung cancer are 22.5%, 37.6%, and 51.2% respectively and 3.5%, 6.9% and 47.2% respectively for patients with liver cancer.The VG-PC gating system could improve treatment efficiency when performing respiratory gated MR-IGRT for patients with lung or liver cancer. However, there were no evidences to suggest that other factors including patient's sex, age, and the exact location of the tumor have effect on the performance of the VG-PC gating system.H. Choun: None. H. An: None. H.Jin: None. J. Kim: None. C. Choi: None. J. Park: None.

Design of gating system for radiator die castings based on FLOW-3D software

According to the structural characteristics of the radiator, two different gate structures were designed. The filling process of metal liquid in different gate structures was simulated by using the simulation software FLOW-3D, the size and location of possible defects in die casting were predicted, and the best design scheme of gate and overflow trough was put forward. The results show that under the conditions of pouring temperature of 680°C, preheating temperature of mold of 220°C and pouring speed of 60m/s, the most reasonable design scheme is that the whole casting can be filled with molten metal evenly and the concentration of surface defects is low.

First experimental results of gated proton imaging using x-ray fluoroscopy to detect a fiducial marker

Increasing numbers of proton imaging research studies are being conducted for accurate proton range determination in proton therapy treatment planning. However, there is no proton imaging system that deals with motion artifacts. In this study, a gated proton imaging system was developed and the first experimental results of proton radiography (pRG) were obtained for a moving object without motion artifacts. A motion management system using dual x-ray fluoroscopy for detecting a spherical gold fiducial marker was introduced and the proton beam was gated in accordance with the motion of the object. To demonstrate the performance of the gated proton imaging system, gated pRG images of a moving phantom were acquired experimentally, and the motion artifacts clearly were diminished. Also, the factors causing image deteriorations were evaluated focusing on the new gating system developed here, and the main factor was identified as the latency (with a maximum value of 93 ms) between the ideal gating signal according to the actual marker position and the actual gating signal. The possible deterioration due to the latency of the proton imaging system and proton beam irradiation was small owing to appropriate setting of the time structure.

Calculation and Simulation of Aluminium Alloy Flange Reducer Cast Using Resin Sand Mold

One of the causes of defects in casting is due to poor gating system design. In conventional casting methods, the gating system design process is carried out by trial and error to find the best design results. Computer modeling and simulation offer process design in a much faster time, and at much less cost, compared to conventional methods. The gating system design approach with a combination of well calibrated simulation software can avoid defect before casting. Casting simulation helps to visualize the phenomena of filling, molten metal solidification, and shrinkage porosity. The resulting casting simulation can be displayed in graph variants at specific nodes with line graphs or numerical numbers manually. This study discusses the simulation of casting a flange reducer from aluminum alloy material using a resin sand mold. The initial dimensions of the gating system used are sprue of 14.5 x 8.4 x 180 mm, runner 147 x 10 x 5.5 mm, ingate 80 x 10 x 5.5 mm with a bottom gate channel system. Total of dominant porosity that occurs using the initial gating system is 65.31 % and show the undirectional solidificiation behavior. After modifying the gating system and increasing the riser size, the simulation results show directional solidification behavior starting from the thinnest part to the thickest part and ending at the riser. The shrinkage porosity can compensate with the total of porosity is 57.60 % at the riser . Modification of the channel system is required to obtain a sound casting or porosity free.

Photothermally induced liquid gate with navigation control of the fluid transport

The ability to control multiphase flows is essential for applications such as microvalves, chemical analyses, microreactors, and multiphase separators. Furthermore, more specific controls, including the positional navigation control of fluids under steady-state pressures, will improve the development of these applications. Here, we present a fundamentally new photothermally induced liquid gating system that allows light-controlled contactless fluid transport and gas/liquid separations at designated locations, with seconds response times, under constant pressures. Experiments and theoretical calculations demonstrate the stability of our system and its novel regulation mechanism, which is based on a photothermally induced liquid-reconfigurable gate with a change in the surface/interfacial tension and Marangoni flow redistribution of the gating liquid at the illuminated location. This regulation mechanism with positional navigation properties requires neither mechanical parts nor complex accessories and can further enable the miniaturization and integration of various engineering processes. Our application demonstrations confirm the potential of this system in fields of smart valves, multiphase separations, multiphase microreactors, and beyond.

Optimization of Shrinkage Porosity in Grinding Media Balls by Casting Design Modification and Simulation Technique

Shrinkage porosity or cavity are associated with the solidification of the metal either due to gas/air entrapment or when the shrinkage occurring during solidification is not entirely compensated by the riser. Shrinkage cavities occurring in the casting reduces its strength which leads to unfulfillment of the desired serviceability. In this paper, casting design has been modified using the DISA manual to achieve directional solidification which directly relates to improvement of casting quality. The running of metal from pouring basin into casting along with solidification has been analysed through PROCAST which is a casting simulation software based on Finite Element Method and CAFE (Cellular Automata Finite Element) Model. The feeding system of the casting has been modified in terms of shape and volume to minimize air aspiration effect and promote directional solidification. The model used is of grinding media balls casting of high chromium cast iron. The feeding pattern, feeding velocity and solidification with respect to pouring temperature, pouring rate, ambient temperature and film coefficient has been analysed. The final optimum range of all parameters with corresponding minimum shrinkage porosity in casting was obtained. Main aim was to minimize shrinkage porosity in the main casting, ignoring gating and feeding system. The actual minimization of shrinkage porosity comes out around 56 %.

PO-1986 Early toxicity with stereotactic body radiation therapy for prostate cancer

Purpose or Objective: Stereotactic body radiotherapy (SBRT) has proven to be a new option for localized prostate cancer. SBRT specific indications has been transformed due to SARS-2-COVID19 scenario. This communication shows our data about acute toxicity in patients treated with SBRT during the last sixteen months. Materials and Methods: This retrospective and observational study was performed on prostate cancer patients admitted into our radiotherapy department for SBRT between October 2019 until January 2021. SBRT treatment at our institution has been standardized as an IGRT technique using VMAT radiation therapy due to deliver total doses of 36.25 or 40 Gy in 5 fractions. The following variables were recorded: age, past medical history, previous treatment with anticoagulant or antiplatelet drugs, Performance Status (PS), ACE-27 score, IPSS score, Gleason score, Prostate Volume, Tumor Stage, PSA levels, Risk group following NCCN, Hormonotherapy, Radiation Area, RT Doses as well as different toxicity types depending on Genitourinary (GU) or Gastrointestinal (GI) location. Toxicity review was recorded (after RT, six month and 12 months) according to Common Terminology Criteria for Adverse Events (CTCAE). For the descriptive analysis, analytical variables were represented using absolute and relative frequencies. All statistical analysis were conducted using software from SPSS (version 25.0, Chicago, IL). The hypothesis of our study is SBRT technique will reduce radiotherapy sessions with a low rate of toxicity. Results: A total of 47 patients were included, with a median age of 71 years, performance status 0-1, including high risk prostate cancer (25 patients with Gleason score 6, 17 with score 7, 4 with score 8 and 1 with score 9), all of them without seminal vesicles affected. Related to NCCN risk group, 57.4 % of the patient had very low risk, low risk and favorable intermediate risk and 42.6% were unfavorable intermediate, high and very high risk. Androgen deprivation was associated in 40.4% of the cases with a median of treatment in six months (RI:6-24). Image Guided Radiotherapy was performed by matching of fiducial markers on kvCBCT images that were acquired prior to treatment, for positioning, and during treatment, for intrafraction movement control in 74.5% of the patients. The remaining 25.5% were treated by means of a gating system guided by continuous transperineal ultrasound scanning (Clarity ®system). Acute toxicity grade 1 and 2 after RT was greater at GU (51.1%/21,3%) than GI (12.8%/4.3%) location. During subsequent follow-up no patient developed acute GU or GI toxicity greater than or equal to grade 2. At 6 and 12 months evaluation GU toxicity was greater than GI, 31.7% Vs. 17.1% and 12%Vs.4%, respectively. Conclusion: Evaluation of toxicity during the early phase SBRT has proven to be a well tolerated treatment for prostate cancer in our series.