1. INTRODUCTION

A knowledge based system is a computer program that uses knowledge to solve complex problems. The knowledge’s are gain using various knowledge representation techniques rules, frames and scripts. Having this in hand, will gave user documentation of knowledge, intelligent decision support, self learning, reasoning and explanation of the system. Knowledge based systems further enhanced the expert system technology into the decision making framework. Expert system has been the tools and techniques perfected by researchers to deduce decision influences based on codification of knowledge.

There are four different system software’s needed to manufacture part (e.g. Fish Head) in the manufacturing production. First of all is Computer Aided Design (CAD). It involves the use of computer to create design drawing and product models. The CAD design is usually associated with interactive computer graphics known as CAD system. CAD is the process to create the modeling for object by using the three elements which are computer graphics, geometry modeling and design. CAD system is a powerful tool and is used in the design and geometric modeling of components and products (McMohan, C. and Browne, J. 1998). Second is the Computer Aided Process Planning (CAPP). It is a tool to simplify and improve process planning. The planning begins with engineering drawings, specifications, parts or material lists and a forecast of demand (Kalpakjian, S. and Schmid, S. 2006).

Thirdly is Computer Aided Manufacturing (CAM) which involves the use of computers to assists in all phases of manufacturing a product. Computer Aided Design and Computer Aided Manufacturing often are combined into CAD/CAM systems. This combination allows the transfer of information from the design stage into the stage of planning for manufacture without the need to reenter the data on part geometry manually. CAD/CAM software functionality is to calculate and generate tool paths and NC programs that imply a certain approach to processing based on the design compensating for the cutter's geometry, adding federate, spindle commands and others (Kalpakjian, S. and Schmid, S. 2006). Finally the CNC control software that will function as the brain to all the systems. CNC control software will read the tool paths and all the instructions given by all software for cutting the material and becoming the output known as product.

2. OBJECTIVE OF STUDY AND PROBLEM STATEMENT

1. Objective of Study

To propose CATIA software as a tool in covering CAD, CAPP and CAM process steps which include the process of generating program, designing, planning and simulating which in return, reduce the time/delay in production line. By implementing CATIA software, the time cost for process steps in CAD, CAPP and CAM can then be eliminated.

2. Problem Statement

Design, program, and simulating part (e.g. Fish Head) will require the knowledge on CAD, CAPP, CAD/CAM and CNC control. Fish Head alone will require many processes during fabrication which include designing, process planning, machining and others fabrication steps. These processes if not well manage will contribute to cost of handling, setting due to the processes involve throughout completing a project. The steps to implement the project are as in Figure 1.

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Figure 1: Step to implement the project

CATIA in the other hand offers a solution to model complex and intelligent products where it can supports multiple stages of product development, from conceptualization, design, engineering, and manufacturing. All activity conducted are as shown in Table 1.

Table 1: Activity throughout completing this project

|ITEM |ACTIVITY |
|CAD files |Research in website to get more information |
| |Sketch with hand the drawing to identify the dimension. |
| |Generate detail drawing by using the CATIA software. |
| |Give detail information about the drawing and dimension. |
| |Revised detail of drawing |
| |Finalized detail drawing |
|CAPP files |Determine the process planning and work plan |
| |Generate the setup process of product drawing |
| |Research and determine the tool used |
|CAM files |Make the simulation for machining of the product. |
| |Checking lost data transfer and discuss with team member. |
| |Generate tool path information and machine strategy. |
| |Determine the problem in machining and solve with change the CAPP processes if needed. |
| |Identifying the best processing machining for the part such the plane surface that need to machine. |

3. METHODOLOGY

1. Knowledge Acquisition and Elicitation

Knowledge acquisition is a process to gain the knowledge and information from all sources other than people. However, the knowledge elicitation is a process of obtaining the requirements of a system from user, customer and other stakeholder. Under these circumstances, both methods are required to gain knowledge and information as much as possible to insure sufficient data are collected.

Processes like protocol analysis, flow diagram and past design are all taken into consideration when conducting knowledge gathering. Other than that, interviews, and observation for evaluation are conducted to gain information as recommended by knowledge elicitation approaches. Knowledge from external experts are also required by cooperating them with the internal expert to reduce the inaccessibility, insufficient knowledge on elicitation and as an in depth explanation on intelligence system deployment.

2. Knowledge Representation

The production rules method has been deployed to represent the knowledge in forward reasoning strategies. It is used due to its advantages to their user. By conducting rule in the process, it can guide the user for further action. Developers and users can also modify part of the rule without breaking the entire system. Collected information can also be incorporated into the system simply by adding new rules without any concern on how it will fit into the overall knowledge base and finally to the overall process.

3. Verification and Validation

Verification is the process of checking the model and the corresponding program to ascertain that they performed as intended. However, validation is the process of determining whether the model, as a conceptualization or an abstraction is meaningful and accurately represented to the real system. The main purposes of verification and validation process are to produce a model that represent true system behavior close enough for the model to be fit in for the real system and to maintain the credibility of a simulation model. 4. Implementation

The implementation phase for the product was not much differ to the conventional process because each process consists of normal procedure in manufacturing process and it is conducted using same parameters setting just that process of re-setting for different process are neglected. However, knowledge on using expert system is required and familiarity of the overall system is a must before moving towards expert system. All management staff should also trained in order to ensure the overall process are well understood where they became more alert on the system where it require access and on gathering knowledge and information on the product including for further analysis and maintenance.

5. Maintenance

It is important to have an organized tree structure which gives ease for navigation of the features when any modification takes place. The machining body features are grouped under one body and base block features in another and so on with appropriate feature operations. It is also important in structuring the reference and construction element so that the design intent is transparently achieved.

Renaming features within the design becomes mandatory as it will be useful for the end users to by far identify things for modification. Doing this will ease identification of features and bodies in specification tree. User will also able to use search command effectively to find features and any modification of features will becomes easier.

Any external data that are to be handled in the model can be grouped under a geometrical set called input data which can be used in the model when situation demands. By grouping the foreign elements in a separate geometrical set it is easy to identify them in the specification tree. No more mixing up of Model features with input data. The dependency can easily trace. Some input data like planes can be reverted back to parametric geometries and easy identification of Foreign Elements.

It is also advisable that dimensioning and constraining the sketches are in a logical manner and the global parameters offset plane dimensions are declare which will drive the whole Geometry in terms of position.

4. CONCLUSION AND DISCUSSION

CATIA facilitates collaborative engineering across disciplines, including surfacing and shape design, mechanical engineering, equipment and systems engineering. It provides a suite of surfacing, reverse engineering, and visualization solutions to create, modify, and validate complex innovative shapes. From subdivision, styling, and Class A surface to mechanical functional surfaces. CATIA enables the creation of 3D parts, from 3D sketches, sheet metal, composites, mold, forged or tooling parts up to the definition of mechanical assemblies.

Implementing advanced concepts and practices in CNC machining by using the CATIA software that are advanced computer programming of CNC turning (turn/mill) with specific processes such as facing, profile turning, boring, grooving and threading will further enhance productivity due to lower setup time for designing, process planning, machining and others fabrication steps. Using CATIA software as the main tool especially to generate program, designing, planning and simulating the product is a must in order to ensure the productivity of a product that can met business target and customer demand. CATIA offers a solution to model complex and intelligent products through the system engineering approach. It covers the systems architecture, the behavior modeling and the virtual product.

5. REFERENCES

[1] Chang, T.C, Richard A. W, Hsu-Pin Wang. (2006). “Computer-Aided Manufacturing, 2nd Edition”. Prentice Hall.

[2] Kalpakjian, S. and Schmid, S. (2006). “Manufacturing Engineering and Technology, fifth edition” Singapore: Prentice Hall, pp.1203-1206.

[3] McMohan, C. and Browne, J. (1998). “CAD/CAM Principles, Practice and Manufacturing Management” Prentice Hall, p. 166-167.

[4] http://en.wikipedia.org/wiki/Verification_and_validation

[5] http://www.comp.nus.edu.sg/~teoym/cs6205/9900/L4/sld003.htm