The Generation of Machining Process Plans Using a Haptic Virtual Reality System

Author(s):  
C. A. Fletcher ◽  
J. M. Ritchie ◽  
T. Lim

Computer Aided Process Planning (CAPP) links the design and manufacture of a machined product defining how the product itself will be manufactured. Decisions made during this phase can have a significant impact on product cost, quality and build time; therefore, it is important that process planners have intuitive tools to aid them in effectively creating process plans. However, in spite of being a strong research area, the actual application of CAPP systems in industry is limited and new modern 3D digital tools in this area have not been researched to any real degree. Traditional process planning is carried out either manually or via a CAPP interface and, from this activity, a set of instructions are generated for the shop floor. However, these CAPP processes can be time consuming and subject to inconsistencies. Current research seeks to automate the generation of work instructions by using previous designs and/or artificial intelligence. However, due to the complexity of manufacturing a wide range of products, the limited range of tools available and differing skills of the workforce, it is difficult to reach a generic solution for practical application. The novel pilot study given in this paper presents one of the first pieces of research comparing and contrasting a traditional manual approach to machined part process planning with an alternative haptic virtual environment. Within this, an operator can simulate the machining of a simple part using a virtual drilling and milling process via a haptic routing interface. All of the operator input is logged in the background with the system automatically generating shop floor instructions from this log file. Findings show that users found the virtual system to be more intuitive and required less mental workload than traditional manual methods. Also their perceptions for the future were that they would need less support for learning and would progress to final planning solutions more quickly.

1994 ◽  
Vol 116 (1) ◽  
pp. 108-116 ◽  
Author(s):  
H. Cho ◽  
A. Derebail ◽  
T. Hale ◽  
R. A. Wysk

A formal approach for integrating Computer-Aided Design (CAD), Computer-Aided Process Planning (CAPP), and shop floor control for rotational components is presented in this paper. It is assumed that this approach will be implemented within the framework of a three level hierarchical CIM architecture that consists of the following levels in the hierarchy: shop floor, workstation and equipment (Joshi et al., 1991). Our approach to CAPP consists of machining feature identification, definition, classification, representation, and reasoning, provided through a CAD model of a product. Geometric entities are identified from a Drawing Exchange Format (DXF) file. The identified entities form the basis for the construction of primitive manufacturing features. The primitive features are assembled together based upon the precedence among features, into a graph, called a feature graph. However, the primitive features may or may not be manufacturable in terms of depth of cut, tool geometry, surface finish, and material handling required. Hence it is necessary to convert the feature graph into a manufacturing task graph, which consists of specifications of alternative functional tasks that are manufacturable. The task graph may be converted into a hierarchical set of process plans, based on the planning criteria at each level in the control hierachy, to reflect the processing requirements at each level. The shop planning function decomposes the task graph into a set of workstation level plans. Each workstation level plan is aggregated into a set of equipment level process plans by the workstation planning function. The equipment level plan is converted into a unique task sequence by the equipment planning function. This sequence is then executed according to specifications by the equipment level execution function. Provision of alternative routes in process plans provides for flexible means of on-line planning and control.


Author(s):  
Nikolaos A. Fountas ◽  
Constantinos I. Stergiou ◽  
Nikolaos M. Vaxevanidis

Despite the fast development and the continuous evolution of computer-aided systems for product design, analysis and manufacturing, an unlinked gap appears between the interfaces of computer-aided design (CAD) and computer-aided process planning (CAPP) modules. Various CAPP systems have been built to address this problem and forward a “passage” to link the design phase and the planning of manufacturing processes; hence, providing precise technical instructions in the shop-floor. To support the manufacturing trends and contribute to the research efforts for the realization of precise, reliable and efficient process plans, a set of programmable support functions are presented in the form of an object-oriented software application that enable process planners to produce accurate process plans for aircraft parts and components.


1988 ◽  
Vol 4 (03) ◽  
pp. 197-215
Author(s):  
Richard L. DeVries

The use of computers to improve the productivity of U.S. shipyards has never been as successful as hoped for by the designers. Many applications were simply the conversion of an existing process to a computerized process. The manufacturing database required for the successful application of computer-aided process planning (CAPP) to the shipyard environment requires a "back-to-basics" approach, one that can lead to control of the processes occurring in the fabrication and assembly shops of a shipyard. The manufacturing database will not provide management feedback designed for the financial segment of the shipyard (although it can be converted to be fully applicable): it provides "real-time" manufacturing data that the shop floor manager can utilize in his day-to-day decisions, not historical data on how his shop did last week or last month. The computer is only a tool to be used to organize the mountains of manufacturing data into useful information for today's shop manager on a "real time" basis. The use of group technology to collect similar products, the use of parameters to clearly identify work content, the use of real-time efficiency rates to project capacity and realistic schedules, and the use of bar codes to input "real time" data are all tools that are part of the process—tools for the shop floor manager of tomorrow.


1992 ◽  
Vol 114 (1) ◽  
pp. 31-40 ◽  
Author(s):  
U. P. Korde ◽  
B. C. Bora ◽  
K. A. Stelson ◽  
D. R. Riley

Research on generative computer-aided process planning (CAPP) for turned parts using combined fundamental and heuristic principles is presented. The rationale for the process planning approach is that many preconditions of machining processes can be expressed as a small number of domain principles. The domain is defined by processes and the part description as features for simple turned parts. The motivation is to detect faulty designs early on in the design process. Preliminary designs defined by features are first evaluated using manufacturability rules in a rule-based expert system, developed in LISP. Manufacturability rules are based on feature properties such as accessibility, stability, and critical material thickness. The rules were acquired from design and manufacturing personnel from industry through interviews. Parts that satisfy the manufacturability checks are used to generate all feasible process plans. A search algorithm selects the “best” process plan from the feasible set. Process plans are generated and subsequently optimized using two distinct sets of feasibility and optimality criteria which may be either fundamental or heuristic in nature. The presently incorporated criteria successfully restrict the set of plans to a small number without missing any apparently feasible process plans. Manufacturability evaluation, feasible process plans, and optimal process plans for actual industrial parts have been obtained and compared.


2012 ◽  
Vol 472-475 ◽  
pp. 2100-2106 ◽  
Author(s):  
Zhuang Yao ◽  
Dong Yu ◽  
Jun Feng Tian ◽  
Liao Mo Zheng ◽  
Yi Hu

With manufacturing industry tending to high-mix low-volume production, the turn-mill machining technology has recently received much attention. This research proposes the programming method using process planning and kinematic based on the existing problems during the course of the programming for the mill-turn machine. Firstly, through computing the volume of removal shape on the cylindrical blank shape, dividing the machining process for the spindles. Then recognizing the turning and milling process and computing their removal shape for obtaining tool path. According to complex configuration of the mill-turn machine, the machine kinematic chain is created to convert cutter location data generated into the NC data. Finally the effectiveness of the programming method is confirmed by machining experiment.


Author(s):  
Quanwei Hu ◽  
Lihong Qiao ◽  
Guanwei Peng

Computer-aided process planning is an important component for linking design and manufacturing in computer-aided design/computer-aided process planning/computer-aided manufacturing integrated manufacturing systems. Operation sequencing in computer-aided process planning is one of the most essential tasks. To solve the problem and acquire optimal process plans, operation sequencing is modeled as a combinatorial optimization problem with various constraints, and a novel modified ant colony optimization algorithm is developed to solve it. To ensure the feasibility of process plans, constrained relationships considered among operations are classified into two categories called precedence constraint relationships and clustering constraint relationships. Operation precedence graph based on constrained relationships is formed to get visual representation. To ensure good manufacturing economy, in the mathematical model for optimization, total weighted production cost or weighted resource transformation time related to machine changes, setup changes, tool changes, machines and tools is utilized as the evaluation criterion. To avoid local optimum and enhance global search ability, adaptive updating method and local search mechanism are embedded into the optimization algorithm. Case studies of three parts are carried out to demonstrate the feasibility and robustness of the modified ant colony optimization algorithm, and some comparisons between the modified ant colony optimization algorithm and previous genetic algorithm, simulated annealing algorithm, tabu search and particle swarm optimization algorithm are discussed. The results show that the modified ant colony optimization algorithm performs well in the operation sequencing problem.


Author(s):  
Jhy-Cherng Tsai ◽  
Weirong Tsai

Abstract This paper presents a knowledge-base approach that assists a designer to evaluate possible process plans and associated costs based on tolerancing specifications of the designed part. It is an effort to take dimensional tolerances into computer-aided process planning (CAPP) for cylindrical parts through the usage of databases and knowledge bases. Geometric features with tolerancing specifications in a CAD system are first used to determine possible machining operations that can achieve the specified tolerances based on data from the machining feature database, the process precision grade database, and the precision grade database. Process plans are then generated based on rules and knowledge from process sequence knowledge base and the machining feature database. Possible process plans are further organized as a graph. Optimal process plan with least cost is then selected by searching through the graph. This is achieved based on machine set-up and operation costs that are derived from the machine tool resource database, the process parameter database, and the machine set-up and operation cost database. A CAPP software prototype supporting tolerance design on the AutoCAD platform is also demonstrated with examples to illustrate this approach.


Author(s):  
Debaslsh Dutta ◽  
Yong Se Kim ◽  
Youngjin Kim ◽  
Eric Wang ◽  
Derek Yip-Hoi

Abstract An integrated system to support both product and manufacturing process design should be such that (1) the part design can be evaluated and redesigned based on manufacturability analysis and (2) the manufacturing processes can be selected efficiently and flexibly exploiting product information provided by part design representations. In this paper, we describe the collaborative research of the University of Illinois at Urbana-Champaign (UIUC) and the University of Michigan (UM) in computer-aided process planning for mill-turn machining. The UIUC geometric reasoning system based on convex decomposition identifies the machining features and maps the negative feature volumes to machining process methods, and generates geometry-based machining precedence relations. The UM process planning system based on genetic algorithm determines machining process sequences and assignment to multiple spindles and turrets.


2014 ◽  
Vol 1036 ◽  
pp. 897-902 ◽  
Author(s):  
Cezary Grabowik ◽  
Krzysztof Kalinowski ◽  
Iwona Paprocka ◽  
Wojciech Kempa

The need of integration of all engineering activities starting from a designing stage finishing on manufacturing implies the necessity of application of a new software solution. Among them CAPP systems seem to be the best and the most promising integration tool. There are the two basic methods of the computer aided process planning it is the variant and generative methods. These CAPP modelling methods are based on the different principles. The variant method is based, in general, on the ideas of the design similarity and group technology whilst the generative one mainly on the basis of utilization of the manufacturing knowledge store and the automatic process synthesis. It is a well-known fact that the variant process planning approach is based on the hypothesis that similar parts would have similar process plans. In a CAPP variant process planning system it is necessary to look for similarities between parts. Process plans formerly prepared and stored in the CAPP system manufacturing database are used for planning of new manufacturing processes for new parts similar to those recorded in system database. In the variant system working out of the classification schema and similarity measures is essential. In this paper an attempt to application of chain codes for a design similarity evaluation is presented. The proposed procedure is based on application of the chain codes for description of the parts selected longitudinal cross sections. The proposed chain code structure is created in similar way to this used for the Freeman code formation but unlike classic Freeman chain code the parts cross section is discretized in more than the 8 cardinal directions. The characteristic feature of the proposed profile coding method is the approach for the code starting point selection. In each case the part design chain code is created starting from the a priori selected upper left corner of a product. The idea of products similarity evaluation bases on the parts profile codes and application of the minimum edit distance definitions. In the paper the Levenshtein and Hamming distance for code chains similarity comparison are proposed At the current stage of research this method is used for similarity evaluation of rotational symmetric parts. The choice of the minimum edit distance measure in the proposed solution depends on product pins number.


2017 ◽  
Vol 11 (2) ◽  
pp. 242-250 ◽  
Author(s):  
Kenta Koremura ◽  
◽  
Yuki Inoue ◽  
Keiichi Nakamoto

In the manufacturing industry, there is an urgent need to shorten the manufacturing lead time of products. Therefore, optimizing process planning is essential to realize high efficiency machining. In this study, in order to develop a computer aided process planning (CAPP) system using previously proposed machining features, a prediction method for some process evaluation indices is proposed. Many candidates for the machining process exist, depending on the recognized machining features in a previous study. Therefore, by using these indices, operators can select a suitable process from among these candidates according to their ideas. Case studies of process planning are conducted to confirm that the operator’s strategy affects the selection of the machining process candidates. From the case study results, it is found that the proposed process evaluation indices have potential use in determining the machining process utilized, and are suitable for a flexible CAPP system of multi-tasking machine tools.


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