• Title/Summary/Keyword: IS Process

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Characteristic Analysis and Selection of Process Parameters in Direct Rolling Processes (직접압연공정의 특성해석 및 공정변수 선정)

  • 박영준;조형석;이원호;강태욱
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.384-388
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    • 1997
  • Recently,direct rolling process has been drawing increasing interests because production cost be greatly reduced by eliminating subsequent hot rolling processes. Such a process has been characterized to prosuce thin steel strip (thickness 1~5mm) directly from molten metal and to skip over the conventional hot rolling processes. However, since there are several process parameters, which affect the quality of product,and their relationship between the parametersare very complex,it is therefore very difficult to realize the process design and the quality control. To overcome these difficulties quantitative relationship between the parameters are investigated through a numerical analysis. Form these results, it is found that solidification final point is the most important paramter which is critical to quality of the strip. Also,the multiple regression model is obtianed to determine their relationship from the solidification final point and roll separating force which can be easily estimated

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A Study on Tool Monitoring for High Speed Tapping using AE Signal (AE센서를 이용한 고속 탭핑용 공구 모니터링에 관한 연구)

  • 김용규;이돈진;김선호;안중환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.315-318
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    • 1997
  • In terms of productivity, the speed of machining process has been increasing in most of engineering part. But the tapping process does not reach at enough level compared with other machining processes because of its complicate cutting mechanism. In the high speed tapping process, the one of important elements is tool monitoring system to prevent tool breakage. This paper describes tool monitoring system by acoustic emission(AE) in the tapping process. We used 2 types of AE sensors in this test. The one is commercial sensor which is used in other machining monitoring system like polishing and the other is a self-fabricated sensor for this test. In this test we purpose to find out the frequency of AE signal in tapping process and verify the possibility of applying AE sensor in in-process tapping monitoring system. Also grasp of characteristic of tapping process by AE signal is handled.

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Study of Edge Crack Growth According to Rolling Condition in Cold Rolling (냉간압연공정에서 공정변수에 따른 엣지 크랙 성장에 관한 연구)

  • Cui, X.Z.;Lee, S.H.;Lee, S.J.;Lee, J.B.;Kim, B.M.
    • Transactions of Materials Processing
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    • v.18 no.5
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    • pp.377-384
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    • 2009
  • The shape of edge cracking in rolling process generally occurred "V" shape. This cracking is successively generated at width edge of strip. The edge cracking is developed to center of strip during rolling process. In the results, the strip is occurred fracture, and the productivity is gone down because of the extensive production time. Accordingly, we need to control crack propagation during rolling process. But, the control of cracking is very difficult in rolling process. Previously the studies of edge cracking were mainly performed on hot rolling process. In this paper, the shape of the edge cracking in rolling was estimated according to process conditions such as initial edge crack size, reduction ratio and tension using FE-simulation and the simplicity experiments on cold rolling process.

A Study on the Fine Blanking Process of Stopper Part (Stopper 부품의 파인블랭킹공정에 관한 연구)

  • 김영호;손경호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.182-186
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    • 1996
  • In this work, a method is described to investigate the progressive and compound process in the coining and piercing operation for given conditions and parameters, using the FEM simulation and model experiment. The effect of the die shape on the compound process is established, and the die shape depends on the position of coining die and the width of the part coined. It is found that Progressive process is better than compound process, since material's filling into the die is not completed and the higher stress acts on the edge of the punch according to width being increased.

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Pre-Bending Analysis of Tie-Bar for Hydroforming (Hydroforming을 위한 Tie-bar의 예비굽힘성형 해석)

  • 강대철;전병희;성부용
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.255-261
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    • 2000
  • Tube bending is one of the conventional manufacturing process. Recently, tube bending was highlighted in automotive industry by hydroforming. Tube hydroforming process is divided into pre-bending process and hydroforming process. It's initial state is very important in die cavity of first hydroforming process. So tube bending is important factor of the hydroforming process. In this paper, two pre-bending simulations, by a rotary draw bending machine and a bend die. This paper presents the simulation results in pre-bending process that is used to form an automotive part, tie-bar.

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Current Status of Quartz Glass for Semiconductor Process (반도체 공정용 석영유리 현황)

  • Kim, Hyeong-Jun
    • Ceramist
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    • v.22 no.4
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    • pp.429-451
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    • 2019
  • Quartz glass is a key material for making semiconductor process components because of its purity, low thermal expansion, high UV transmittance and relatively low cost. Domestic quartz glass has a market worth about 500 billion won in 2018, and the market power of Japanese materials is very high. Quartz glass for semiconductor process can be divided into general process and exposure. For general process, molten quartz glass is mainly used, but synthetic quartz glass with higher purity is preferred. Synthetic quartz glass is used as the photomask for the exposure process. Recently, as semiconductors started the sub-nm process, the transition from the transmission type using ArF ultraviolet (194 nm) to the reflection type using EUV ultraviolet (13.5 nm) began. Therefore, the characteristics required for the synthetic quartz glass substrates used so far are also rapidly changing. This article summarizes the current technical trends of quartz glass and recent technical issues. Lastly, the present situation and development possibility of quartz glass technology in Korea were diagnosed.

Finite Element Analysis of a Piercing and Trimming Process Having a Spring-Attached Die in Hot Former Forging (열간포머 단조공정중 스프링부착 금형을 가진 피어싱과 트리밍 동시공정의 유한요소해석)

  • 문호근;정재헌;전만수
    • Transactions of Materials Processing
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    • v.12 no.6
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    • pp.536-541
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    • 2003
  • In this paper, the rigid-viscoplastic finite element method is employed together with an iteratively force-balancing method to analyze a piercing and trimming process with a spring-attached die in hot former forging. An actual piercing and trimming process with a spring-attached die is investigated in detail and a generalized analysis model is proposed. A multi-stage hot former forging process is simulated under various spring constants. The analyzed results are discussed in order to investigate the effects of spring constants on the metal flow lines and the formed shapes. Then an optimal piercing and trimming process in hot former forging is devised.

A Study of the Upper Bound Analysis of Extrusion Process with Torsion (토션을 이용한 압출공정의 상계해석에 관한 연구)

  • Park, Chul-Woo
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.4
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    • pp.578-584
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    • 2008
  • In this study, a extrusion process with torsion of the bottom die is investigated to improve the forming performance of conventional extrusion process. In the experiment, plasticine is used as a model material. The results of experiments are compared with the two numerical methods, the Experiment and the Finite Element Method(FEM). An attempt is made to link programs incorporating with the process variables obtained by commercial FEM software, DEFORM-3D a useful package. Numerical result is compared with experimental one. These results show that the torsional extrusion process is very useful process because this process can obtain the homogenous deformations.

Model for Process Quality Assurance When the Fraction Nonconforming is Very Small (극소불량 공정보증을 위한 모형연구)

  • Jong-Gurl Kim
    • Proceedings of the Safety Management and Science Conference
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    • 1999.11a
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    • pp.247-257
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    • 1999
  • There are several models for process quality assurance by quality system(ISO 9000), process capability analysis, acceptance control chart and so on. When a high level process capability has been achieved, it takes a long time to monitor the process shift, so it is sometimes necessary to develop a quicker monitoring system. To achieve a quicker quality assurance model for high-reliability process, this paper presents a model for process quality assurance when the fraction nonconforming is very small. We design an acceptance control chart based on variable quality characteristic and time-censored accelerated testing. The distribution of the characteristics is assumed to be normal of lognormal with a location parameter of the distribution that is a linear function of a stress. The design parameters are sample size, control limits and sample proportions allocated to low stress. These parameters are obtained under minimization of the relative variance of the MLE of location parameter subject to APL and RPL constraints.

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An Investigative Study for the Integration of SPC and EPC (SPC와 EPC 통합에 관한 조사 연구)

  • 김종걸;정해운
    • Journal of the Korea Safety Management & Science
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    • v.4 no.3
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    • pp.107-122
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    • 2002
  • There are two approaches to process control. The one is engineering process control(EPC) which is one of the techniques very widely used in the process industry and based on control theory which aims at keeping the process on target using manipulating variable. The other is statistical process control(SPC) whose main purpose is to look for assignable causes(variability) in the process. To design an integrated or combined scheme of SPC and EPC is gaining recognition in the process experiences for hybrid industry. This paper aims to investigate recent study concerned on the integration of SPC and EPC. First, we consider the difference between SPC and EPC in simple terms and review various models of EPC for integration including evaluation of previous study. Finally, we suggest some prospective research area concerned on the integration of SPC and EPC.