Reduction of scrap percentage of cast parts by optimizing the process parameters

Casting is a widely used manufacturing process in the automotive industry. Die casting is the most popular type of casting processes. But the fact observed in many industries is the scraps or wastages occurring after the process. Thus, this thesis is primarily based on understanding the die-casting process and the factors governing them. In this study, the part to be studied is a throttle body. The raw material used for the production is AlSi9Cu3. The main concern in this part is the occurrence of defects such as bad filling, heat bubbles, and porosity. Thus, it is important to perform process optimization. Techniques or methods such as Design of Experiments, ANOVA analysis, and numerical simulations are used. This thesis also focuses on the use of brainstorming as an industrial discussion tool and the use of quality tools for process optimization. Thus, these techniques are utilized in order to eliminate the defects. The scrap after using these techniques and methods is reduced to 9% from 14% initially found. This investigation has been performed as a continuous improvement project in Sonafi and as a master thesis for “Instituto Superior de Engenharia do Porto”.A fundição é um processo de fabrico amplamente utilizado na indústria automóvel. A fundição injetada é o tipo mais popular de processos de fundição. Mas, o facto observado em muitas indústrias é o aumento de sucatas ou desperdícios que ocorrem após o processo. Assim, esta tese é baseada principalmente na compreensão do processo de fundição e nos factores que a governa. Neste estudo, a parte a ser estudada é um corpo do acelerador. A matéria-prima usada para a produção é AlSi9Cu3. A principal preocupação nesta parte é a ocorrência de defeitos como mau preenchimento, bolhas de calor e porosidade. Assim, é importante realizar a otimização do processo. São utilizadas métodologias como o Desenho de Experiências, análise ANOVA e simulações numéricas. Esta tese também se concentra no uso do brainstorming como uma ferramenta de discussão industrial e uso de ferramentas de qualidade para otimização de processos. Assim, essas técnicas são utilizadas para eliminar problemas ocorridos na produção. Esta investigação foi realizada como um projeto de melhoria contínua na Sonafi e como uma tese de mestrado para o Instituto Superior de Engenharia do Porto

Alternative cut-off and surface finishing of investment castings

The research investigates the capability of replacing the cut-off and gate-removal processes at DePuy Synthes (Ireland) with a single cutting operation. Abrasive WaterJet Cutting (AWJC), laser cutting, Electrical Discharge Machining (EDM) and plasma cutting were considered as alternatives to the current system. Custom investment castings were produced for use in A WJC experiments to determine the cutting speeds for a range of cut thickness (2 to 30 mm) for the Cobalt-Chrominum-Molybdenum (CoCrMo) alloy. Femoral and tray castings, each with different tree designs, were evaluated post knockout (vibratory shell removal). Femoral parts were undamaged by jet deflection or wear when utilising the correct set up of the A WJC nozzle. Using a traverse speed of 130 mm/min, the surface finish at the bottom of the 16 mm thick femoral gate was visually equivalent to the current surface finish obtained after gate removal (Ra of 9 μm). Thin femoral sections (3.2 mm) cut at 400 mm/min achieved an acceptable Ra of 7 μm with a cycle time of 6 minutes per tree, which was 70% lower than the current processing time of 23 minutes. Tray castings cut with a traverse speed of 60 mm/min achieved a surface roughness Ra of 10 μm. However, the process was unsuitable for trays because jet deflection below the cut caused excessive wear to the machined parts. The use of AWJC for femorals has the ergonomic benefit of eliminating all manual grinding in the foundry, as well as labour savings equivalent to a Return-On-Investment (ROI) of two years. Further development of a 3-dimensional (3-0) vision system however is required to automate the AWJC of femoral castings

Technological methods of workpieces manufacturing. Metal Casting: Manual

Manual «Technological methods of workpieces manufacturing. Castings» provides the knowledge regarding different foundry processes and their industrial importance. It is considered the modern techniques of processing raw materials by casting as an important stage of solving the tasks of designing technological processes of manufacturing the parts. Manual includes fundamentals of metal casting, the evolution of foundry industry, basic casting techniques, the metal casting operations, methods of manufacturing the cast blanks; the most rational variants of their manufacturing; equipment, tools and machining attachments for making workpieces of machine elements and parts in different process specifications and conditions. Also focused on efficient design of casting runner, riser, gating system with minimal casting defects and solidification process. Recommended for students of first (Bachelor of Science) level of higher education, 13 «Mechanical Engineering» major, 131 «Applied Mechanics» specialism, and can also be useful for engineering and technical specialists of foundry technologies in the mechanical engineering industry.INTRODUCTION...5 1. EVOLUTION OF METAL CASTING INDUSTRY...6 2. METAL CASTING AS A MANUFACTURING PROCESS...16 3. METALS AND ALLOYS USED IN METAL CASTING 4. FUNDAMENTALS OF METAL CASTING...25 4.1. Metal casting basics: molds, patterns, pattern material, cores, gating and elements of a gating system...27 4.2. The metal casting operation. Pouring, fluidity, risers, shrinkage and other defects...36 4.3. Gases in metal casting. Gases during the manufacture of a casting...43 4.4. Metal casting design. Mold and gating system design, directional solidification, and troubleshooting...45 5. EXPENDABLE MOLD CASTING 5.1. Sand casting...53 5.2. Plaster mold ...62 5.3. Ceramic mold casting...64 5.4. Shell molding...66 5.5. Vacuum casting...70 5.6. Expanded polystyrene casting...74 5.7. Investment casting...77 6. PERMANENT MOLD CASTING 6.1. Basic permanent mold casting...82 6.2. Slush casting...87 6.3. Pressure casting...92 6.4. Vacuum permanent mold casting...95 6.5. Die casting...97 6.6. Hot chamber die casting...101 6.7. Cold chamber die casting...104 6.8. True centrifugal casting...108 6.9. Semicentrifugal casting...112 6.10. Centrifuge casting...117 6.11. Ingot manufacture...122 6.12. Continuous casting...127 7. CASTING DEFECTS 7.1. Casting microstructure and defects...132 7.2. Casting defects and remedies...135 8. COMPUTER SYSTEMS FOR CASTING PROCESSES SIMULATION...149 GLOSSARY...163 REFERENCES...19

Технології виробництва заготовок литтям

У навчальному посібнику «Технології виробництва заготовок литтям» розглянуто еволюцію ливарного виробництва, сучасні методи одержання литих заготовок, класифікацію способів виробництва заготовок литтям, їх переваги та недоліки. Подано фундаментальні основи сучасного виробництва литих заготовок, раціональні варіанти їх виготовлення; обладнання, інструменти та технологічне оснащення для різних технологічних режимів і умов. Для перевірки отриманих знань запропоновано тестові завдання з кожного розділу посібника. Начальний посібник рекомендовано для здобувачів вищої освіти галузі знань 13 «Механічна інженерія», а також для інженерно-технічних працівників ливарної промисловостіThe manual «Technologies of Workpieces Manufacturing by Castings» provides knowledge regarding different foundry processes and their industrial importance. It is considered the modern techniques of processing raw materials by casting as an important stage of solving the tasks of designing technological processes for manufacturing the parts. The manual includes fundamentals of metal casting, the evolution of the foundry industry, basic casting techniques, the metal casting operations, methods of manufacturing the cast blanks; the most rational variants of their manufacturing; equipment, tools and machining attachments for making workpieces of machine elements and parts in different process specifications and conditions. Also focused on efficient design of casting runner, riser and gating system with minimal casting defects and solidification process. Multiple choice questions from each section of the manual are offered to test the acquired knowledge. Recommended for higher education seekers in 13 «Mechanical Engineering» majors, and can also be useful for engineering and technical specialists of foundry technologies in the mechanical engineering industryINTRODUCTION...7 1. EVOLUTION OF THE METAL CASTING INDUSTRY...8 Multiple Choice Questions...18 2. METAL CASTING AS A MANUFACTURING PROCESS...22 Multiple Choice Questions...33 3. METALS AND ALLOYS USED IN METAL CASTING...38 Multiple Choice Questions...54 4. CLASSIFICATION OF METAL CASTING PROCESSES...58 Multiple Choice Questions...62 5. FUNDAMENTALS OF METAL CASTING 5.1. Metal casting basics...64 5.2. Metal casting operations...73 5.3. Gases in metal casting...80 5.4. Metal casting design...82 Multiple Choice Questions...90 6. EXPENDABLE MOLD CASTING 6.1. Sand casting...129 6.2. Plaster mold casting...140 6.3. Ceramic mold casting...143 6.4. Shell molding...146 6.5. Vacuum casting...152 6.6. Expanded polystyrene casting...158 6.7. Investment casting Multiple ...162 Choice Questions...169 7. PERMANENT MOLD CASTING 7.1. Basic permanent mold casting...204 7.2. Vacuum permanent mold casting...213 7.3. Slush casting...216 7.4. Die casting...223 7.4.1. Hot chamber die casting...233 7.4.2. Cold chamber die casting...240 7.5. Pressure die casting...248 7.5.1. Low pressure die casting...253 7.5.2. High pressure die casting...260 7.5.3. Gravity die casting...270 7.6. Centrifugal casting...276 7.6.1. True centrifugal casting...283 7.6.2. Semi-centrifugal casting...288 7.6.3. Centrifuge casting...294 7.7. Squeeze casting...299 7.8. Continuous casting...307 7.9. Evaporative pattern casting...314 7.9.1. Lost foam casting...325 7.9.2. Full mold casting...331 7.10. Stir casting...337 7.11. Ingot casting manufacture...341 Multiple Choice Questions...346 8. CASTING DEFECTS 8.1. Casting microstructure...411 8.2. Casting defects and remedies... Multiple Choice Questions...427 9. COMPUTER SYSTEMS FOR CASTING PROCESSES SIMULATION...433 GLOSSARY...446 REFERENCES...48

Object Detection and Tracking in Cooperative Multi-Robot Transportation

Contemporary manufacturing systems imply the utilization of autonomous robotic systems, mainly for the execution of manipulation and transportation tasks. With a goal to reduce transportation and manipulation time, improve efficiency, and achieve flexibility of intelligent manufacturing systems, two or more intelligent mobile robots can be exploited. Such multi-robot systems require coordination and some level of communication between heterogeneous or homogeneous robotic systems. In this paper, we propose the utilization of two heterogeneous robotic systems, original intelligent mobile robots RAICO (Robot with Artificial Intelligence based COgnition) and DOMINO (Deep learning-based Omnidirectional Mobile robot with Intelligent cOntrol), for transportation tasks within a laboratory model of a manufacturing environment. In order to reach an adequate cooperation level and avoid collision while moving along predefined paths, our own developed intelligent mobile robots RAICO and DOMINO will communicate their current poses, and object detection and tracking system is developed. A stereo vision system equipped with two parallelly placed industrial-grade cameras is used for image acquisition, while convolutional neural networks are utilized for object detection, classification, and tracking. The proposed object detection and tracking system enables real-time tracking of another mobile robot within the same manufacturing environment. Furthermore, continuous information about mobile robot poses and the size of the bounding box generated by the convolutional neural network in the process of detection of another mobile robot is used for estimation of object movement and collision avoidance. Mobile robot localization through time is performed based on kinematic models of two intelligent mobile robots, and conducted experiments within a laboratory model of manufacturing environment confirm the applicability of the proposed framework for object detection and collision avoidance

A study on twin-screw rheo-diecasting of AZ91D Mg-alloy

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.A newly developed one-step semisolid process by BCAST for semisolid processing of magnesium alloy was studied in this thesis - the Twin-Screw Rheo-Diecasting (RDC) of AZ91D Mg-alloy. The RDC process is an innovative process which combines the dispersive mixing power of the Twin-Screw Slurry Maker (TSSM) for creation of high quality semisolid slurry and the existing cold chamber High-Pressure Die-Casting (HPDC) process for component shaping. Magnesium alloys, due to their low density and superior strength/weight ratio, offer distinct advantages in weight savings, and are gaining increasing interests in applications. The research on the new RDC technology aimed to eliminate the limitations of the conventional HPDC and to meet the requirements from extensive application of Mg-alloys. In this thesis, the major tasks were to optimise of the RDC technology, to evaluate the microstructure and mechanical properties of RDC AZ91D Mg-alloy in both as-cast and heat treated conditions, and to understand the solidification process in the TSSM. The results of the RDC as-cast state indicated that the microstructure of primary a-Mg particles had a fine size (around 40μm), extremely spherical morphology and uniform distribution throughout the entire castings; the RDC AZ91D samples had extremely low levels of porosity. Due to the unique microstructure and much reduced level of defects, the RDC AZ91D alloy exhibited a substantial improvement in mechanical properties. In addition, a traditional full heat treatment was performed for RDC AZ91D alloy. Compared with HPDC alloy, the RDC AZ91D alloy was found to exhibit an accelerated dissolution of ß-Mg17A112during solution treatment, and a faster age-hardening kinetics of the ß-phase during subsequent ageing. The microstructural investigations showed that under intensive forced convection, heterogeneous nucleation occurred continuously throughout the entire volume of the solidifying melt and the nuclei grew spherically. Ostwald ripening took place by dissolution of the smaller particles but at a very slow coarsening rate. Increasing the intensity of forced convection enhanced nucleation and reduced volume fraction of primary phase solidified in the slurry maker. This study has demonstrated that the novel RDC process possesses a number of advantages and it is suitable for production of high integrity Mg-alloy components

An examination of the feasibility and design limitations of laminate tooling for pressure die-casting.

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN049978 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Potential of Rapid Tooling in Rapid Heat Cycle Molding:A Review

Rapid tooling (RT) and additive manufacturing (AM) are currently being used in several parts of industry, particularly in the development of new products. The demand for timely deliveries of low-cost products in a variety of geometrical patterns is continuing to increase year by year. Increased demand for low-cost materials and tooling, including RT, is driving the demand for plastic and rubber products, along with engineering and product manufacturers. The development of AM and RT technologies has led to significant improvements in the technologies, especially in testing performance for newly developed products prior to the fabrication of hard tooling and low-volume production. On the other hand, the rapid heating cycle molding (RHCM) injection method can be implemented to overcome product surface defects generated by conventional injection molding (CIM), since the surface gloss of the parts is significantly improved, and surface marks such as flow marks and weld marks are eliminated. The most important RHCM technique is rapid heating and cooling of the cavity surface, which somewhat improves part quality while also maximizing production efficiencies. RT is not just about making molds quickly; it also improves molding productivity. Therefore, as RT can also be used to produce products with low-volume production, there is a good potential to explore RHCM in RT. This paper reviews the implementation of RHCM in the molding industry, which has been well established and undergone improvement on the basis of different heating technologies. Lastly, this review also introduces future research opportunities regarding the potential of RT in the RHCM technique