CAD-DFM
INTEGRATION
BY
SURIYADEV K
2022291010
FEATURES IN CAD-DFM INTEGRATION
• The fundamental approach with existing CAD systems is that they are geometricallyoriented.
• They possess little or no ability to store nongeometrical information which also has a
significant influence on design.
• It is only the human designer's interpretation of these symbols, according to certain
conventions, which makes them meaningful.
EXAMPLE
• Consider a simple hole drilled in a cube of metal. In a drafting system this would be
represented as a circle within a square. This is all the understanding of the part that
the computer has.
• It is only the human designer's interpretation of these symbols, according to certain
conventions, which makes them meaningful.
• The two basic approaches in which features can be used are:
Design Approach
1. Design by features
2. Feature recognition
FEATURE REPRESENTATION METHODOLOGIES
• In the design and manufacturing environment a part can be described in a number of
ways, typical methods being engineering drawings (20), physical models,
• Group Technology (GT) codes, symbolic representations and the modem computerbased geometric representations: wire frame, surface and solid models.
• In prototype realisations of this architecture, a parametric feature-based CAD system
was chosen as the sample CAD system within DEFMAT as it combines both solid
modelling and feature-based design.
ADVANTAGES OF GROUP TECHNOLOGY:
• Group Technology is used to improve the production design by using
computerized design. this is done by using the coding system.
• We can find the required part by entering the code of part this saves the
time and improves in accuracy.
• By using the setups they can reduce the time because similar parts are
used to processed on them.
• Material handling is more effective in this.
• The work done is automated by this time, cost planning is reduced.
• By this the defects identification on parts is very fast.
• It enhances the quality of production.
• Obtain a better control over the process.
CLASSIFICATION OF FEATURES
• A general structure for the definition and implementation of design and manufacturing
features, was developed within which several classes of features were defined :
1. Design feature
2. Manufacturing feature
3. Assembly feature
DESIGN FEATURE
• A parameterised geometrical entity used for building the CAD model.
Several levels of complexity exist :
a) Functional: complex geometry, with a specific function for a product
family.
b) Compound: complex geometry, with no specific function.
c) Basic: the simplest geometrical entities for describing the part.
MANUFACTURING FEATURE
• A parameterised entity linked with one or several alternative
manufacturing methods. It is the link between the
manufacturing knowledge and the designed product.
ASSEMBLY FEATURE
• A parameterised entity linked with one or several assembly
methods. Typically it consists of one or more design features in
the same or several piece parts, belonging to a specific
assembly.
HIERARCHICAL STRUCTURE OF THE FEATURES
• The structure of the features has been split into several areas:
1.
Generic knowledge and data for a wide variety of products. This type of feature
typically represents the basic or compound features as they are usable for all types of
designs.
2.
2. Specific knowledge and data for a product family. Within a product family, specific
functions are defined. This functionality is clearly linked with the functional design
features.
3.
3. Specific information for a process model.
• The set of available manufacturing features is defined by the chosen
Process model. Therefore the description of the product in terms of
manufacturing features will depend on the actual type of process analysed.
• An identical set of design features allows different sets of manufacturing
features. The structure is based on definitions made in CAM-I and ISOSTEP feature classifications.
GENERAL STRUCTURE OF THE DESIGN AND
MANUFACTURING FEATURES
THANK YOU