Material flow during the extrusion of simple and complex cross-sections using FEM

This paper deals with the extrusion of rod and shape sections and uses a 3D finite element model analysis (FEM) to predict the effect of die geometry on maximum extrusion load. A description of material flow in the container is considered in more detail for rod and shape sections in order to fully comprehend the transient conditions occurring during the process cycle. A comparison with experiments is made to assess the relative importance of some extrusion parameters in the extrusion process and to ensure that the numerical discretisation yields a realistic simulation of the process. The usefulness and the limitation of FEM are discussed when modelling complex shapes. Results are presented for velocity contours and shear stress distribution during the extrusion process. It is shown that for most of the shapes investigated, the material making up the extrudate cross-sections originates from differing regions of virgin material within the billet. The outside surface of the extrudate originates from the material moving along the dead metal zone (DMZ) and the core of the extrudate from the central deformation zone. The FE program appears to predict all the major characteristics of the flow observed macroscopically

Material flow during the extrusion of simple and complex cross-sections using FEM

This paper deals with the extrusion of rod and shape sections and uses a 3D finite element model analysis (FEM) to predict the effect of die geometry on maximum extrusion load. A description of material flow in the container is considered in more detail for rod and shape sections in order to fully comprehend the transient conditions occurring during the process cycle. A comparison with experiments is made to assess the relative importance of some extrusion parameters in the extrusion process and to ensure that the numerical discretisation yields a realistic simulation of the process. The usefulness and the limitation of FEM are discussed when modelling complex shapes. Results are presented for velocity contours and shear stress distribution during the extrusion process. It is shown that for most of the shapes investigated, the material making up the extrudate cross-sections originates from differing regions of virgin material within the billet. The outside surface of the extrudate originates from the material moving along the dead metal zone (DMZ) and the core of the extrudate from the central deformation zone. The FE program appears to predict all the major characteristics of the flow observed macroscopically

On Regularity and Integrated DFM Metrics

Transistor geometries are well into the nanometer regime, keeping with Moore's Law. With this scaling in geometry, problems not significant in the larger geometries have come to the fore. These problems, collectively termed variability, stem from second-order effects due to the small geometries themselves and engineering limitations in creating the small geometries. The engineering obstacles have a few solutions which are yet to be widely adopted due to cost limitations in deploying them. Addressing and mitigating variability due to second-order effects comes largely under the purview of device engineers and to a smaller extent, design practices. Passive layout measures that ease these manufacturing limitations by regularizing the different layout pitches have been explored in the past. However, the question of the best design practice to combat systematic variations is still open. In this work we explore considerations for the regular layout of the exclusive-OR gate, the half-adder and full-adder cells implemented with varying degrees of regularity. Tradeoffs like complete interconnect unidirectionality, and the inevitable introduction of vias are qualitatively analyzed and some factors affecting the analysis are presented. Finally, results from the Calibre Critical Feature Analysis (CFA) of the cells are used to evaluate the qualitative analysis

Analysis of Critical Factors for Automatic Measurement of OEE

The increasing digitalization of industry provides means to automatically acquire and analyze manufacturing data. As a consequence, companies are investing in Manufacturing Execution Systems (MES) where the measurement of Overall Equipment Effectiveness (OEE) often is a central part and important reason for the investment. The purpose of this study is to identify critical factors and potential pitfalls when operating automatic measurement of OEE. It is accomplished by analyzing raw data used for OEE calculation acquired from a large data set; 23 different companies and 884 machines. The average OEE was calculated to 65%. Almost half of the recorded OEE losses could not be classified since the loss categories were either lacking or had poor descriptions. In addition, 90% of the stop time that was classified could be directly related to supporting activities performed by operators and not the automatic process itself. The findings and recommendations of this study can be incorporated to fully utilize the potential of automatic data acquisition systems and to derive accurate OEE measures that can be used to improve manufacturing performance

Real-Time data-driven average active period method for bottleneck detection

Prioritising improvement and maintenance activities is an important part of the production management and development process. Companies need to direct their efforts to the production constraints (bottlenecks) to achieve higher productivity. The first step is to identify the bottlenecks in the production system. A majority of the current bottleneck detection techniques can be classified into two categories, based on the methods used to develop the techniques: Analytical and simulation based. Analytical methods are difficult to use in more complex multi-stepped production systems, and simulation-based approaches are time-consuming and less flexible with regard to changes in the production system. This research paper introduces a real-Time, data-driven algorithm, which examines the average active period of the machines (the time when the machine is not waiting) to identify the bottlenecks based on real-Time shop floor data captured by Manufacturing Execution Systems (MES). The method utilises machine state information and the corresponding time stamps of those states as recorded by MES. The algorithm has been tested on a real-Time MES data set from a manufacturing company. The advantage of this algorithm is that it works for all kinds of production systems, including flow-oriented layouts and parallel-systems, and does not require a simulation model of the production system

An algorithm for data-driven shifting bottleneck detection

Manufacturing companies continuously capture shop floor information using sensors technologies, Manufacturing Execution Systems (MES), Enterprise Resource Planning systems. The volumes of data collected by these technologies are growing and the pace of that growth is accelerating. Manufacturing data is constantly changing but immediately relevant. Collecting and analysing them on a real-time basis can lead to increased productivity. Particularly, prioritising improvement activities such as cycle time improvement, setup time reduction and maintenance activities on bottleneck machines is an important part of the operations management process on the shop floor to improve productivity. The first step in that process is the identification of bottlenecks. This paper introduces a purely data-driven shifting bottleneck detection algorithm to identify the bottlenecks from the real-time data of the machines as captured by MES. The developed algorithm detects the current bottleneck at any given time, the average and the non-bottlenecks over a time interval. The algorithm has been tested over real-world MES data sets of two manufacturing companies, identifying the potentials and the prerequisites of the data-driven method. The main prerequisite of the proposed data-driven method is that all the states of the machine should be monitored by MES during the production run

Materials selection analysis for vibration isolator pads

Isolator pads which also called as vibration pads are used in many applications to isolate vibration, extend machine life, reduce maintenance costs and reduce excessive wear. It is the process of isolating objects such as equipment from harmful vibration sources. In this study, two types of isolator pad materials; neoprene and sorbothone were analyzed in order to be used for stackable washing and dryer machine. In this case, the stackable washing and dryer machine together with the isolator pads were simplified into two degree of freedom system, where the first and the second natural frequencies for each material of isolator pad were determined by using matrix iteration method, in which later were validated by a modern tool such as Matlab. For neoprene material, the first natural frequency obtained was 44.2 rad/s and the second natural frequency is 107.7 rad/s. By contrast, sorbothone material shows slightly higher for both first and second natural frequencies compared to neoprene, which were 57.9 rad/s and 141.0 rad/s respectively. From this result, it shows that neoprene is suitable to be used as the coupling (spring) material since it has lower natural frequency value compared to sorbothone, besides the second natural frequency of sorbothone material is near to the forcing frequency 140 rad/s, thus could amplified the vibration due to resonance

The effect of fertilization and spacing on the yield and composition of soybeans

Among the agricultural crops of the United States soybeans, Glycine max. rank fourth in value. The response of this crop to direct fertilization and spacing between rows is inconsistent. The reasons for the lack of response are frequently not known. It has been suggested that one of the important phases of research on soybean nutrition might be to study the relationships between spacing and the nutrient needs of the crop. One phase of this study pertained to the response of soybean yield components to varying fertilizer application and different spacings between rows. Soybeans generally respond to lime applied to acid soils. These responses are in part related to the availability and uptake of other nutrients. A greenhouse experiment to determine the influence of lime and potash on the growth and composition of soybean plants was conducted

Street Dance in Temples of Perambalur District and its Impact

Developing a rural area is good for a city. Villages are places where civilization and culture are recreated. The family members feel happy and proud when close relatives visit their house. The villagers keep praying to the gods to protect the happiness of their family. During the worship people of various ethnicities unite and they organize many programs. Various cultural arts events and games are performed in these festivals. Artists participates and show off their skills in the events. At these times artists are given gifts and appreciation. Thus, the street dancers receive friendship and love from the audience as they express their artistic skills with various techniques. Although there are many events that can happen during the festival season, the one event that can impress the audience are street dance. The narrative element of the story acts as a bridge between the performers and the audience. The plot of the story is about the glory of the ancient leaders and the history of the deities. All these performances are done with the hope that it will influence the minds of the country people and guide them in their lives

Comparison of Target-Controlled Infusion vs. Manual Infusion of Propofol on Postoperative Recovery in Gynecological Endoscopic Procedures: An Open-Label Randomized Controlled Trial

Background: TIVA with propofol using a manually controlled infusion technique may cause delayed recovery or awareness due to overdosing or underdosing of an anaesthetic. However, TCI can optimally deliver anaesthetic by adjusting the infusion rates based on the pharmacokinetic profile of propofol. This study aimed to compare the recovery time after termination of propofol infusion in TCI with that of the manual infusion technique in patients undergoing gynaecological endoscopic procedures. Methods: In this randomized trial, 100 female patients (18–65 years, American Society of Anesthesiologists (ASA - I/II) undergoing gynaecological endoscopic procedures were assigned to Manual or TCI propofol infusion. The Manual group (n=50) received propofol using the Bristol formula, while the TCI group (n=50) received a pump targeting 4 mcg/ml (Marsh model). Recovery time, total propofol dose, and post-induction MAP changes were measured with target BIS value of 40–60. Results: The demographic data were comparable between the groups. The recovery time was faster with the TCI group (478.4±52.76 seconds) than the manual group (505.8±65.15 seconds) (p=0.0229). No significant difference was observed in total propofol consumption (p=0.199), with mean values of 14.47±1.24 mg/kg/hr in Group T and 14.12±1.46 mg/kg/hr in Group M. Patients in manual infusion group had better haemodynamic parameters than TCI group with less fall in mean arterial pressure post-induction. A significant difference was found in the percentage change in MAP (p=0.0003), with Group T showing a mean change of 9.18±2.6% and Group M 11.2±2.8%. Conclusion: TCI offers significantly shorter recovery time and better post-induction haemodynamic parameters than manual propofol infusion in patients undergoing gynaecological endoscopic procedures