Predictive Maintenance in Injection Molding Process

ChulSoon Park,DugHee Moon 한국산업경영시스템학회 2014 한국산업경영시스템학회 학술대회 Vol.2014 No.춘계

In this research, we are developing a predictive maintenance model of the injection molding machines based on the prediction of trend of injection molding parameters. At first, we developed an interface method to directly monitor the real-time injection molding parameter data from injection molding machine controller. Second, we identified the principal injection parameters which mainly affect the quality of injection molding products and need to be monitored for maintenance. Third, based on the time series analysis, we developed the prediction models of the principal injection molding parameters, which are identified by previous statistical model to forecast its future patterns/trends and schedule its maintenance point in time. We adopted Nelson’s rules to identify abnormal patterns in predicted data. Finally, we used FTA (fault tree analysis) to relate the injection molding parameters to the parts of the injection molding machine, find out the equipment or parts to be corrected.

Logistics Allocation and Monitoring System based on Map and GPS Information

Chulsoon Park,Larsson Bajracharya 한국산업경영시스템학회 2018 한국산업경영시스템학회지 Vol.41 No.4

In the field of optimization, many studies have been performed on various types of Vehicle Routing Problem (VRP) for a long time. A variety of models have been derived to extend the basic VRP model, to consider multiple truck terminal, multiple pickup and delivery, and time windows characteristics. A lot of research has been performed to find better solutions in a reasonable time for these models with heuristic approaches. In this paper, by considering realtime traffic characteristics in Map Navigation environment, we proposed a method to manage realistic optimal path allocation for the logistics trucks and cargoes, which are dispersed, in order to realize the realistic cargo mixing allowance and time constraint enforcement which were required as the most important points for an online logistics brokerage service company. Then we developed a prototype system that can support above functionality together with delivery status monitoring on Map Navigation environment. First, through Map Navigation system, we derived information such as navigation-based travel time required for logistics allocation scheduling based on multiple terminal multiple pickup and delivery models with time constraints. Especially, the travel time can be actually obtained by using the Map Navigation system by reflecting the road situation and traffic. Second, we made a mathematical model for optimal path allocation using the derived information, and solved it using an optimization solver. Third, we constructed the prototype system to provide the proposed method together with realtime logistics monitoring by arranging the allocation results in the Map Navigation environment.

Measuring a Value of Contract Flexibility in the Third-Party Warehousing

Chulsoon Park,Bowon Kim 한국경영과학회 2009 Management Science and Financial Engineering Vol.15 No.1

This paper considers the value of warehousing contract under probabilistic demands. We consider a supply chain consisting of a supplier, a retailer and its third-party warehousing partner who provides the warehousing service to the retailer through an outsourcing contract. A typical contract is specified by initial space commitment and modification schedule. The retailer decides the order quantity for the supplier and space commitment for the outsourcing contract. Since there is close relationship between order quantity and space commitment to minimize the total cost including ordering cost, inventory carrying cost, shortage cost, and warehousing cost, we develop an analytical model under probabilistic demands, where the retailer can determine the optimal order size and space commitment level jointly. We found the closed-form optimum for a single-period case and the optimal conditions for a two-period case. To evaluate the value of contract flexibility for the twoperiod case, we compared the total cost under two policies; one with modification, under which the base commitment can be changed at the start of each period and the other without modification. From results of our numerical analysis, we showed that the modification policy is more cost-effective as the variability of demand increases.

A predictive maintenance approach based on real-time internal parameter monitoring

Park, Chulsoon,Moon, Dughee,Do, Namchul,Bae, Sung Moon Springer-Verlag 2016 INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TE Vol.85 No.1

<P>Since continuous real-time components or equipment condition monitoring is not available for injection molding machines, we propose a predictive maintenance approach that uses injection molding process parameters instead of machine components to evaluate the condition of equipment. In the proposed approach, maintenance decisions are made based on the statistical process control technique with real-time data monitoring of injection molding process parameters. First, machine components or equipment of injection molding machines, which require maintenance, is identified and then injection molding process parameters, which may be affected by malfunctioning of the previously identified components, are identified. Second, regression analysis is performed to select the process parameters that significantly affect the quality of the lens and require a high degree of attention. By analyzing the patterns of real-time monitored data series of process parameters, we can diagnose the status of the components or equipment because the process parameters are affected by machine components or equipment. Third, statistical predictive models for the selected process parameters are developed to apply statistical analysis techniques to the monitored data series of parameters, in order to identify abnormal trends. Fourth, when abnormal trends or patterns are found based on statistical process control techniques, maintenance information for related components or equipment is notified to maintenance workers. Finally, a prototype system is developed to show feasibility in a LabVIEWA (R) environment and an experiment is performed to validate the proposed approach.</P>

개방형 혁신 네트워크의 동태적 모형

박철순(Chulsoon Park) 한국경영과학회 2015 한국경영과학회지 Vol.40 No.1

Literatures on open innovation have two major limitations. First, either on a firm level or on an industry level did they analyze the open innovation issues. The results of a firm’s innovation can be diffused through the whole network and the firm can learn back from the network knowledge. Prior literatures did not consider the feedback loop among firms and network in which the firms are involved. Second, most open innovation research had a static perspective on firm’s innovation performance. Since the diffusion, spill-over and learning among network members are involved over time, the open innovation is intrinsically dynamic. From the dynamic perspective, we can appreciate the fundamental attributes of the open innovation network which involves diverse firms, research institutes, and universities. In order to overcome the limitations, we suggest a dynamic model for open innovation network. We build an agent-based model which consists of heterogeneous firms. The firms are connected through a scale-free network which is formed by preferential attachment. Through the diverse scenario of simulation, we collect massive data on the firm level and analyze them both on firm and industry level. From the analysis, we found that, on industry level, the overall performance of open innovation increases as the internal research capability, absorptive capacity, and learning curve coefficient increase. Noticeably, as the deprecation rate of knowledge increases, the variability of knowledge increases. From the firm level analysis, we found that the industry-level variables had a significant effect on the firm’s innovation performance lasting through all the time, whereas the firm-level variables had only on the early phase of innovation.

대형 항공부품용 5축 가공기에서의 예측정비에 관한 연구

박철순(Chulsoon Park),배성문(Sungmoon Bae) 한국산업경영시스템학회 2020 한국산업경영시스템학회지 Vol.43 No.4

In the process of cutting large aircraft parts, the tool may be abnormally worn or damaged due to various factors such as mechanical vibration, disturbances such as chips, and physical properties of the workpiece, which may result in deterioration of the surface quality of the workpiece. Because workpieces used for large aircrafts parts are expensive and require strict processing quality, a maintenance plan is required to minimize the deterioration of the workpiece quality that can be caused by unexpected abnormalities of the tool and take maintenance measures at an earlier stage that does not adversely affect the machining. In this paper, we propose a method to indirectly monitor the tool condition that can affect the machining quality of large aircraft parts through real-time monitoring of the current signal applied to the spindle motor during machining by comparing whether the monitored current shows an abnormal pattern during actual machining by using this as a reference pattern. First, 30 types of tools are used for machining large aircraft parts, and three tools with relatively frequent breakages among these tools were selected as monitoring targets by reflecting the opinions of processing experts in the field. Second, when creating the CNC machining program, the M code, which is a CNC auxiliary function, is inserted at the starting and ending positions of the tool to be monitored using the editing tool, so that monitoring start and end times can be notified. Third, the monitoring program was run with the M code signal notified from the CNC controller by using the DAQ (Data Acquisition) device, and the machine learning algorithms for detecting abnormality of the current signal received in real time could be used to determine whether there was an abnormality. Fourth, through the implementation of the prototype system, the feasibility of the method proposed in this paper was shown and verified through an actual example.

기업 간 협업 네트워크의 창발

박철순(Chulsoon Park) 한국경영과학회 2015 한국경영과학회지 Vol.40 No.4

This paper proposes relational capability as a main driver of constructing inter-organizational collaboration networks. Based on social network theory and relational view literature, three components of relational capability are constructed and implemented by an agent-based model. The components include organizational capability, structural capability, and trust between a partner and a focal firm. These three components are updated by two micro mechanisms: structural mechanism and relational mechanism. Structural mechanism is a feedback loop in which the relational capability increases structural capability and vice versa. Relational mechanism is a learning-by-doing process in which a focal firm experiences success or failure of collaboration and the experience increases or decreases cumulative trust in a partner firm. Result of agent-based simulation shows that a collaboration network emerges through interactions of firm’s relational capabilities and the characteristics of emerged networks vary with the contribution of structural capability and trust to relational capability. Specifically, in case structural capability contributes more to relational capability, the average degree centrality and collaboration proportion increases as time passes and enters into an equilibrium state. In that case, almost every firms participated in the network collaborates each other so that the emerged network becomes highly cohesive. In case trust contributes more to relational capability, the results are reversed. In an equilibrium state, the balance of contribution between structural capability and trust makes an emerged network larger and maximizes average degree centrality of the network.

중소 제조업의 개방형 혁신이 혁신 성과에 미치는 영향

박철순(Chulsoon Park) 한국생산관리학회 2012 한국생산관리학회지 Vol.23 No.3

본 연구는 중소 제조업의 개방형 혁신 노력이 혁신 성과에 미치는 영향을 살펴보았다. 특히, 개방형 혁신 노력과 혁신 성과 간의 관계를 개방형 혁신 파트너의 만족도가 조절하는지 2009년 중소기업 기술통계조사 자료를 바탕으로 실증하였다. 그 결과, 기업의 내부 혁신 노력과 개방형 혁신 노력 모두 혁신 성과에 긍정적 영향을 주는 것으로 나타났으며, 혁신 파트너와의 만족 수준에 따라서 개방형 혁신 노력이 혁신 성과에 미치는 영향은 다르게 나타났다. 특히 대학과 외국 기업과의 협력 만족도가 유의한 조절 효과를 가졌다. 또, 기업 수명 주기에 따라서 혁신 파트너의 조절 효과는 다른 것으로 확인됐다. 수명 주기의 네 단계 중 성장기와 구조조정기에서만 혁신 파트너의 조절 효과가 유효한 것으로 나타났다. Based on large-sample survey data of small- and medium-sized Korean manufacturing firms, we investigate the relationship between open innovation effort and innovation performance. Specifically, we address a research question whether there exist the moderating role of satisfaction of innovation partners on the relationship. Empirical findings using hierarchical moderated regression analyses suggest that both internal and open innovation effort increase innovation performance. In addition, we find that satisfaction with innovation partners moderates the relationship between the open innovation efforts and innovation performance. We further find that according to the corporate life cycle there is different significance of the moderating role of innovation partners satisfaction. Only at growth and decline stages, the satisfaction of innovation partners significantly moderates the relationship between open innovation efforts and innovation performance.

자동차 산업 공급 네트워크의 상류와 하류 구성 동인의 비교

박철순(Chulsoon Park) 한국생산관리학회 2024 한국생산관리학회지 Vol.35 No.1

Modern industry is a competition between supply networks. Knowing and managing the supply network well is an essential survival requirement for a company. There is a difference in orientation between the upstream and downstream of the supply network, which causes structural differences between the upstream and downstream. This study aims to reveal the differences in the configuration drivers of the upstream and downstream automotive supply networks. Using transaction data from the automotive industry, we compared the drivers that constitute supply networks and create upstream and downstream links. The Exponential Random Graph Models (ERGMs) were used to evaluate the significance of configuration drivers, including company attributes, dyadic attributes, and structural characteristics. As a result, the age of supplier, size of the purchaser, sales of the purchaser, asset of the purchaser, transitivity, and activity were found to be common drivers of upstream and downstream. On the other hand, the age of the purchaser, the difference in sales between the two companies, and popularity were found to be significant drivers only in the downstream network. These research results are the first to empirically compare the upstream and downstream supply networks, and have academic contribution as the first step in finding the cause of the differences in network structure between the upstream and downstream networks. 현대의 산업은 공급 네트워크 간 경쟁이다. 공급 네트워크를 잘 알고 관리하는 것은 기업의 필수 생존 요건이다. 공급 네트워크의 상류와 하류는 지향점에 있어 차이가 있고 이는 상류와 하류의 구조적 차이를 일으킨다. 본 연구는 자동차 공급 네트워크 상류와 하류의 구성 동인의 공통점과 차이점을 밝히고자 한다. 자동차 산업의 거래 데이터를 이용하여 공급 네트워크를 구성하고 상류와 하류의 링크를 만드는 구성 동인을 비교했다. Exponential Random Graph Model(ERGM)을 활용하여 기업의 속성, 양자 간 속성, 구조적 특성을 포함하여 구성 동인들의 유의성을 평가하였다. 그 결과, 공급처의 업력, 구매처의 규모, 구매처의 매출액, 구매처의 자산규모, 이행성, 활동성이 상류와 하류의 공통적인 구성 동인으로 밝혀졌다. 반면, 구매처의 업력, 양자 간 매출액 차이, 스타성은 하류 네트워크에서만 유의한 구성 동인으로 밝혀졌다. 이러한 연구 결과는 공급 네트워크의 상류와 하류를 처음으로 실증 비교한 것이며, 상류와 하류의 네트워크 구조 차이의 원인을 찾아내는 첫걸음이라는 학술적 의의가 있다.

보완적 혁신의 확산

박철순(Chulsoon Park),박상선(Sangsun Park) 한국경영학회 2014 經營學硏究 Vol.43 No.6