A review on integrated process planning and scheduling <s> Closed-Loop Process Planning <s> Automated process planning (APP) has received a considerable amount of attention in recent years. This has mainly been due to APP allowing for the bridging of the gap between design and manufacturing, and for its automation of the related tedious human task. While there have been several efforts in developing interfaces between computer-aided design (CAD) and APP, little attention has been given to the integration of APP and scheduling, which is likely to be of even higher importance. This paper addresses the basic issues involved in the integration of the two functions, demonstrates a methodology and the potential benefits of the integrated approach by an example, and presents directions for future research. <s> BIB001 </s> A review on integrated process planning and scheduling <s> Closed-Loop Process Planning <s> Abstract Dynamic process planning is concerned with the integration of process planning with scheduling. This paper presents the computer-aided process planning (CAPP) system, PARIS, that is meant to be integrated with a scheduling system. The approach to dynamic process planning implemented divides the planning tasks into the two phases: static and dynamic planning. This paper discusses the overall approach and focusing on the details of the implementation of the static phase. An example is used to illustrate the concepts presented. <s> BIB002 </s> A review on integrated process planning and scheduling <s> Closed-Loop Process Planning <s> Abstract To meet the competitive demands of modern manufacturing, it is necessary to reduce design times and enrich decision making by integrating process planning into the design activity using Concurrent Engineering principles. Although this is traditionally done through the interaction between designers and process planners, it is perhaps more desirable for a CAD system to have the functionality necessary to automatically advise the designer of the shop floor implications of design decisions. Cutting tool selection is an essential thread linking feature-based design of machined parts to process planning. Thus, the implementation of tooling considerations into design is an important requirement for an integrated CAD/CAPP system. This paper defines an architecture to enable the vertical integration of tooling considerations from early design to process planning and scheduling. The architecture is based on a five-level tool selection procedure which is mapped to a time-phased aggregate, management and detailed process planning framework. This paper draws on literature and the results of an industrial survey to identify the tooling methods suitable for integration within a CAD system and categorises them into the five levels of tool selection. The functions are then placed on a time-dependent framework that covers the progression of a product from design to process planning. The new functionality is being implemented as an object-oriented application called VITool, which is being developed so that it can be fully integrated within an existing CAD system. <s> BIB003 </s> A review on integrated process planning and scheduling <s> Closed-Loop Process Planning <s> Real time machine tool control and the planning activities which precede manufacture are usually interfaced through a low level language which allows little more than position, feed, and speed information to be passed between the two systems. The higher level systems used to describe geometry and tool paths also lack an adequate capability to describe manufacturing processes. The authors discuss the provision of a much richer interface between the planning and control activities which both facilitates the identification and scheduling of suitable monitoring tasks and allows the updating of process plan data from real time measurements. The result of such integration is an improvement in the efficiency of real time optimisation, and perhaps most importantly the possibility of quasi real time process planning. A system that is able to perform both initial process planning and plan refinement based upon low level feedback must also encompass the path generation activity, such a system is referred to by the authors as a dynamic process planning system. The paper describes the fundamentals of the process models, identification algorithms, control strategies, and low level process plan generation used within such an integrated system. <s> BIB004 </s> A review on integrated process planning and scheduling <s> Closed-Loop Process Planning <s> This paper introduces a dynamic facilitating mechan is m for the integration of process planning and scheduling in a batch-manufacturi ng environment. This integration is essential for the optimum use of production resources and generation of realistic process plans that can be readily executed with little or no modification. In this paper, integration is modeled in two le vels, viz., process planning and scheduling, which are linked by an intelligent facilitator. The process planning module employs an optimization approach in whi ch the entire plan solution space is first generated and a search algorithm is t hen used to find the optimal plan. Based on the result of scheduling module an u nsatisfactory performance parameter is fed back to the facilitator, which then i dentifies a particular job and issues a change to its process plan solution spac e to obtain a satisfactory schedule. <s> BIB005 </s> A review on integrated process planning and scheduling <s> Closed-Loop Process Planning <s> A unique method for the integration of process planning and scheduling in a batch-manufacturing environment is reported. This integration is essential for the optimum use of production resources and for the generation of realistic process plans that can be readily executed with little modification. The integration problem is modelled at two levels: process planning and scheduling, which are linked by an intelligent facilitator. The process-planning module employs an optimization approach in which the whole plan solution space in terms of available machines, tools, tool accessibility and precedence constraints is first generated and a search algorithm is then used to find the optimal plan. For a given set of jobs, the scheduling module takes the optimal plans for each job and generates a schedule based on a given criterion, as well as the performance parameters (machine utilization and number of tardy jobs). An unsatisfied performance parameter is fed back to the facilitator, which then identifies a partic... <s> BIB006 </s> A review on integrated process planning and scheduling <s> Closed-Loop Process Planning <s> Abstract Computer aided process planning (CAPP) and scheduling are two major activities in a modern manufacturing system. The existing CAPP systems have not taken account of shop floor conditions while developing process plans. This paper discusses the importance of integration of scheduling and CAPP and proposes a method for the same. There can be several methods to machine a part and several machines capable of performing the process required to complete the part. Based on this concept, this paper suggests a method of scheduling and its integration with CAPP, so that on-line process plan can be generated taking into account the availability of machines and alternative routes. A scheduling factor for an operation and machine combination has been defined taking into consideration the actual working conditions and capabilities of the machines. Finally operation–machine assignment is made on the basis of these actual scheduling factors. This helps in generating more realistic process plans and helps in improving the efficiency of the manufacturing system as a whole. <s> BIB007
The methodology of CLPP is using a dynamic process-planning system with a feedback mechanism. CLPP can be used to generate real-time process plans by means of a dynamic feedback from production scheduling system. The process-planning mechanism generates process plans based on available resources. Production scheduling provides the information about which machines are available on the shop floor for an incoming job to process planning, so that every plan is feasible and respects to the current availability of production facilities. This dynamic simulation system can enhance the real-time, intuition and manipulability of process-planning system and also enhance the utilisation of alternative process plans. CLPP can also be called as dynamic process planning or online process planning. The basic flow chart of CLPP is shown in Figure 2 . CLPP can bring the IPPS to a real integration system very well. BIB001 developed an automated planning environment to treat the process planning and scheduling as a unified whole. This method could use time window to control the planning quantity in every stage. BIB002 divided the dynamic process planning to the static phase and the dynamic phase. BIB003 defined architecture to enable the vertical integration of tooling considerations from early design to process planning and scheduling. The architecture was based on a five-level tool selection procedure, which was mapped to a time-phased aggregate, management and detailed process-planning framework. BIB004 presented a dynamic process-planning system, which could give the process plans based on the feedback of scheduling system. BIB005 and BIB006 introduced a dynamic facilitating mechanism for IPPS in a batch manufacturing environment. BIB007 introduced a method of scheduling and its integration with CAPP, so that online process plan could be generated taking into account the availability of machines and alternative routes.  introduced a kind of dynamic CAPP system integration model and used the Back Propagation (BP)-based neural network and relevant algorithm to make machine decision. And, the process plans from this dynamic CAPP system could accord with the production situation and the requirements of the job shop scheduling.