Computer Aided Design Yrd.Doç. e mail: azsenalp@gyte.edu.tr Makine Mühendisliği Bölümü Gebze Yüksek Teknoloji Enstitüsü
Design 2
Integrating The Design and Manufacturing Process Through a Common Datase A Scenario Example: Audio system cabinet design Goals: Better quality Lower cost Quick delivery Design description: 4 spaces are needed in the cabinet 1. CD player 2. Cassette player 3. Reciever 4. Storage compartment of CD s 3
Integrating The Design and Manufacturing Process Through a Common Datase A Scenario Preliminary Design: The designer can draw a lot of design concepts. During this phase, according to the need can make 2 or 3 dimensional models Photorealistic images of preliminary designs can be created. Preliminary designs submitted to acceptance: The design concept is sent to the market via e mail to measure the response Selection of the model that should be designed and feasibility study: Most admired model that collects the most sales potential will be the selected model. When the design concept is completed, data is stored to the database: furniture fiction: The amount of shelf, the information such where to use which shelf are categorised and saved to database and in need can be recalled from the database and changed accordingly. 4
Integrating The Design and Manufacturing Process Through a Common Datase A Scenario Determining the dimensions of the cabinet: Its overall size should be determined so that each space within it can accommodate various models of the audio components on the market. Thus it is necessary to obtain information on the sizes of the audio components available. This information may be obtained from catalogs or retrieved from manufacturers' or distributors' databases. Determining the material to be used for the cabinet: The designer could specify natural oak, natural pine, particle board, steel sheet, or some other material. However, in the case of products that operate under severe conditions, such as mechanical assemblies, the designer must be guided by the material's properties. The database is useful in this phase also because properties of many materials can be stored in it for later retrieval and use. 5
Integrating The Design and Manufacturing Process Through a Common Datase A Scenario determining the thickness of each shelf and door and the side walls: The thickness of the shelves must be sufficient to avoid deflection caused by the weight of the audio components. However, in mechanical assemblies requiring high accuracy or a structure supporting heavy loads, dimensions such as thickness must be determined to avoid excessive deformation. The finite element method is generally used to calculate the deformation of a structure. By evaluating the deflection of the shelves while varying the thickness of the shelves, the designer can determine the proper thickness of the shelves and store that information in the database. In addition acoustic analysis may be necessary. Assembly technique: Assembly technique is determined by an expert system. 6
Integrating The Design and Manufacturing Process Through a Common Datase A Scenario Cabinet details: When the design conceptualization, analysis, and optimization phases have been completed, the designer moves on to design documentation to specify the details of the cabinet. The part drawings of the shelves, doors, and side walls are generated by using computer aided drafting. In this phase, the designer can add more details for aesthetic purposes. 7
Integrating The Design and Manufacturing Process Through a Common Datase A Scenario To make the cabinet, each part shape is arranged on the raw material, in this case sheets of wood, and cut out with a saw. Waste can be reduced by arranging the parts efficiently on the wood sheets. The designer can try various parts layouts on the com puter screen until obtaining a layout with minimum waste. The computer program can facilitate this process by calculating the amount of waste for each layout. Also a nesting program that automatically provides the most economic layout can be used. Furthermore, software tools may be used to design the jigs and fixtures for this cutting process and to pro gram the materials handling systems. These systems may be conveyor belts or robots that transfer the raw material and the cut parts to and from the saw. 8
Integrating The Design and Manufacturing Process Through a Common Datase A Scenario Once prepared, the parts have to be assembled. Ideally, the assembly process can also be carried out by robots that are programmed automatically from the descriptions of the final product and its parts that are stored in the database. The jigs and fixtures for the assembly process can also be designed simultaneously. In addition, a robot can be programmed to paint the cabinet after it has been assembled. This scenario is summarized in figure given in next page. It shows how the CAD, CAM, and CAE activities are integrated through the database, which is the objective of CIM. 9
CAD, CAM and CAE Integration Through the Database 10
Part Model 11
Finite Element Mesh 12
Applying Boundary Conditions 13
Results:Displacement 14
Results:Equivalent Stress 15
Pressure Vessel Analysis Geometric model 16
Pressure Vessel Analysis Finite element model 17
Pressure Vessel Analysis Boundary conditions 18
Pressure Vessel Analysis Equivalent stress distributions 19
Example Part Solid Model 20
Finite Element Analysis 21
Flow Analysis 22
Die Design 23
CNC Cutter Locations 24