Proposes a methodology and architecture suitable for generating the process plan of machining parts.

Rahimic, Senad ; Visekruna, Vojo

Abstract: This paper proposes a methodology and architecture suitable for generating the process plan of machining parts. It is a proposal in which the peripheral processes needed for these parts are taken into account and they also enable the development of alternative process plans. The architecture supports the construction of CAPP systems from prepackaged, plug-compatible software components. The specifications of the architecture and its building blocks are defined. A prototype system is under development to prove the concept. This paper proposes a methodology and architecture suitable for generating the process plan of machining parts. It is a proposal in which the peripheral processes needed for these parts are taken into account and they also enable the development of alternative process plans.

Key words: methodology, architecture, CAPP system

1. Introduction

The manufacturing industry has been pushed to adopt more effective and efficient production strategies to meet the challenge of shorter life cycle, higher quality, lower cost, wider variety of customer demands. This increased emphasis on achieving highly adaptive manufacturing to reduce manufacturing costs and to better utilize manufacturing capacity has led to a critical focus on agile manufacturing as a strategy to achieve these goals. In manufacturing, process planning is the task that transforms the design information into the manufacturing processes and determines the operation sequence. CAPP is considered a crucial link between Computer -Aided Design (CAD) and Computer -Aided Manufacturing (CAM). Research of over 30 years in CAPP has resulted in a wealth of knowledge on CAPP and many experimental and commercial CAF'P systems have been developed as a result. Most researchers have focused on a particular aspect of process planning and very few have addressed the issue of system architecture and integration of sub-systems. The current CAPP systems are general and in a closed form, i.e., it is very difficult to modify these systems to suit a user's dynamic needs. This, along with other obstacles in CAPP research, inevitably resulted in the unsuccessful practical implementation of CAPP, particularly in manufacturing environments with constantly changing products and manufacturing resources. In this study, a novel architecture is proposed for rapid development of CAPP systems for agile manufacturing.

2. Methodology for process planning

As mentioned above, the methodology indicates the procedure adopted for determining the process plan of a part. It therefore establishes the steps to be resolved and the order they take. It also has a considerable influence on the planning system's degree of generality and flexibility (Van Houten and Van't Erve 1988). A suitable methodology will establish the functions to be performed--they should be straightforward--the degree of generality each of them must achieve, and how the plan is built up. This is a very important aspect when not only one plan is to be generated, but when there is a group of alternative plans. The requirements demanded of a methodology for developing general and flexible CAPP systems for machining parts are as follows. Take into account not only the machining processes, but also other processes closely linked to it in the final stages of part manufacture such as heat treatment, coating, cleaning and debarring operations.

Assess process plans with regard to the quality obtained in the product and the manufacturing costs, performing an in-depth study of the resources used that play a part in these factors. . Enable the generation of alternative process plans at all levels: processes, machines, fixtures, etc., assessing the production cost in each case. A process planning methodology is influenced by the input data or part data, and the output data or process plan chart data. Before the methodology proposed is discussed, we will take a look at the part and process plan data.

The proposed methodology is shown in figure 1. As mentioned above, the methodology starts from part information using machining features and its quality (Gonza'lez F.; & Rosado, P.) specifications.

[FIGURE 1 OMITTED]

Its purpose is to establish all the viable alternative process plans, organizing them as sequences of phases, set-ups and operations. The different steps of this methodology are as follows raw material. The first stage is to determine the raw material for machining the part. In a part model based on machining features, this raw material may be specified in the part model. Otherwise, this stage is responsible for specifying raw material taking into account other forming processes to obtain the pre form (molding, plastic deformation, cutting, welding, etc.). Therefore, this is a function that includes process planning for processes that are different to machining. As a result, it is placed in the context of a generic planning or a macro-plan before machining. Using the part's input model, this step consists of determining the model that the system will use to work with. This model will be based on the definition of the part with certain machining features, complying with two conditions that distinguish it from the input format. The volume of data is growing at an unprecedented rate, both in the number of features (attributes) and object (instance). For example, many data base with genetic information may contain thousands of features for large number of patients. (Ben-Arieh, D.; Gutin, G.; Penn, M.; & Zverovitch, Y.)

The first condition is that all the machining features will be simple. For this purpose, compound features will be broken down into simple features. The second condition is that the properties for each of these simple machining features include both their shape and quality specifications for manufacturing of features. It also considers the part as a whole, taking into account factors such as, for example, and its accessibility. This means moving on to a model of machining features where the definition of each feature contains individual information as well as information about the rest of the part, assignment of processes and operations.(Kusiak, A.) Using the part model obtained in the previous stage and based on simple machining features, it is possible to determine the processes that are technologically able to achieve them and the operations necessary for these processes. The strategy proposed is to assign to each feature all the processes and operations that may be applicable to the

2.1. Proposed methodology proposed for capp

Computer-assisted process planning was originated in the 1960s (Niebel 1965) and since has been a very active area of research and development. During the late 1970s, the science of computer-aided process planning (CAPP) evolved into two basic approaches: variant or generative process planning (Chang 1998). Modern approaches toward CAPP include using case-based reasoning (Ben-Arieh 1997).[3] In this paper proposed of methodology show on figure 2, which is start by geometric information about part using basic features. Target make all alternative variants process planning, as organizated by sekvence phas, scheduled and operations, this technological to steps different.

The modul devolped for searching basic mechanical features (groove revolution, slot, thread, plane, cylinder cone outer, cylinder cone inner,...etc.) must has two condations, the first conditation is all features to be simple, and make together complex features defineed rotation part. The second condation had defined features by every simple features to be individuale.

[FIGURE 2 OMITTED]

Whole part considerationed, searching from plans simple features which made complex rotation part, with their individual informations possibled define proces and commission technolgy for resumption destitute operations for to do any assignment basic features. stage enactive all features, all process and operations which can to be applicabled for make with acceptable declaration qulity.

3. An object-oriented knowledge representation scheme

We propose an appropriate knowledge representation scheme which attems to address various facets of the process planning task. We recommendanobject-oriented approach for describing process planning related entities and the relations among them, and for development of automated process planning systems. The objectoriented approach object which during process planning exchange messages figure 3.

Each object carries data that identify it through a set of attributes, functions that define its behaviour thriugh appropriate methods, and links to other object through associations with other objects. Each kind of object is represented as a hierarchy with realationship is-a between them and instance at the bottom level.

[FIGURE 3 OMITTED]

Lower objects in the hierarchy inherit common attributes and/or their values from higher level objects. Taxonomies of features, processes, machines and tools exist in the sematic network.

Inheritance is used to infer attributes and behaviour of more specific object. (Hang-Wai, L.; & Hon-Yuen, T.) a number of represent manufacturing capabilities and reasoning in process planning. Now we will explain some of these taxonomies and relations in more detailusually, an automatic process planner should be able to reason about manufacturing features that may be machined in a single opration and/or with s single tool and/or on a single machine. The set of frames is usually obtained through the interface between process planning and design, show on figure 4. (Visekruna, V.; Petkovic, D. & Rahimic, S.)

[FIGURE 4 OMITTED]

3.1. Example of application

The showed rotation part on figure 7 which consisted by anymore basic features, which enabled devolpin altarnative plan variant process planing and search its variant which enabled less cost process planing. The part dimension based on define feautures beginning material with corect dimension and type materala by make part sowed in figure 5. The basic features made by coding: Groove revolution: GRO1, GRO2. ., slot: SLO1, SLO2, SLO3..., thread: THR1..., plane: OD1, OD3, OD5, OD7, OD10, cylinder cone outher: OD2, OD4, OD6, OD8, OD9, cylinder cone inner: HO1.

[FIGURE 5 OMITTED]

4. Object-linking and embedding with excel

VBA (Visual Basic for Applications) within Excel, your dimensions to cell contents within an Excel worksheet. The Excel file can then be embedded within a Solid Works document to create a stand-in application which links to the Solid Works API (Application Programming Interface). We will creation the application shown in figure 6.

[FIGURE 6 OMITTED]

On figure 7, showed programming VBA routine in connection, between Solid Works and Microsoft applications. This has been s fairly simple example, and very little of MS Access power and the Solid Works API has been shown here. With a little more effort, rule-of-thumb design can be incorporated into models as design intent using Access and Solid Works API functions. This exercise has used some of the same procedures you would use to create an application with Visual Basic or Active X

[FIGURE 7 OMITTED]

5. Conclusion

In this paper proposed a methodology and architecture suitable for generating the process plan of machining parts. It is a proposal in which the peripheral processes needed for these parts are taken into account and they also enable the development of alternative process plans. These characteristics enable standardized CAPP systems for general application in industry. These characteristics are largely based on the methodology proposed, the functional structure, the use of general information models and the general functional procedures. All these factors working together give the system its qualities. The development of the CAPP system based on this proposal has demonstrated the system's feasibility and its optimal qualities. The process plans offered by the system constitute all of the alternatives for the sequence of phases, guaranteed by a high degree of optimization with regard to cost and number of phases. These alternatives explicitly include feasible alternatives for machines and, as a consequence, alternative processes for operations (depending on the type of machine for each phase). Using different alternatives at phase level leaves the solution open in a passive way at lower resource levels (fixtures and tools), yet also, in an active way, since the extreme capacities of fixtures and tool resources have been taken into account in the machine capacities.

4. References

Ben-Arieh, D.; Gutin, G.; Penn, M.; & Zverovitch, Y.; Process planning for rotational parts using the generalized travelling salesman problem, int. j. prod. res., 2003, vol. 41, no. 11, 2581-2596

Gonzalez, F.; & Rosado, P.; General and flexible methodology and architecture for CAPP: GF-CAPP system, int. j. prod. res., 2003, vol. 41, no. 12, 2643-2662

Hang-Wai, L.; & Hon-Yuen, T.; Object-oriented analysis and design of computer aided process planning system, Int. Journal CIM--vol 13, 2000.g.,

Kusiak, A.; Decomposition in Data Minning: An Industrial Case Study, IEEE Transactions on electronics packagin manufacturing, 2000

Visekruna, V.; Petkovic, D. & Rahimic, S. (2004). A contri-bution of the generative gt-system in the filed of forging industry, Proceedings of 4th International Symposium on Intelligent manufacturing system--IMS Sakarya, Turkey

Authors' data: Mr. Sc. Rahimic S.[enad], Prof. Dr. Sc. Visekruna V.[ojo], Faculty of Mechanical engineering Mostar, Bosnia and Herzegovina, senad.rahimic@unmo.ba, vojo.visekruna@sve-mo.ba

This Publication has to be referred as: Rahimic, S. & Visekruna, V. (2006). Proposes a Methodology and Architecture Suitable for Generating the Process Plan of Machining Parts, Chapter 41 in DAAAM International Scientific Book 2006, B. Katalinic (Ed.), Published by DAAAM International, ISBN 3-901509-47-X, ISSN 1726-9687, Vienna, Austria

DOI: 10.2507/daaam.scibook.2006.41