CAD/CAM: Computer-Aided Design and Manufacturing

• Computer-Aided Design and Computer-Aided Manufacturing (CAD/CAM) involves using digital computers to perform design and manufacturing functions
• CAD/CAM aims at fully automating the factory of the future by integrating design and manufacturing

Role of Computers in Manufacturing

• Products have characteristics that relate to customer requirements
• Quality is related to the lifecycle loss caused by a product to society
• Optimizing product design is important for production improvement, cost and achieving scheduled delivery times
• Computers should be used in industrial manufacturing
  • Pre-processing support
  • Monitoring and controlling the manufacturing process
  • Post-processing support

CAD

• CAD is a design process using computer graphics and software packages
• CAD aids in analytical, development, costing, and ergonomic design issues
• The stages of a CAD process
  • Geometric model definition
  • Translator definition
  • Interface algorithms
  • Design and analysis algorithms
  • Drafting and detailing
  • Documentation

CAM

• CAM involves using computer systems to plan, manage, and control manufacturing
• CAM uses direct or indirect computer interface with production resources
• The CAD process generates the geometric model that forms the basis for CAM
• CAM activities use different types of data from the CAD process
  • Interface algorithms
  • NC programming
  • Tool ordering
  • Fixtures
  • Computer-aided quality control software

Product Lifecycle

• The product cycle begins with a concept that is refined into a design engineering plan
• Conventional product lifecycle stages
  • Design
  • Part print preparation
  • Tool ordering
  • Machine ordering
  • Material ordering
  • Tool layout
  • Production scheduling
  • Manufacturing operations
  • Standard work establishment
  • Quality control
  • Production

Computer-Aided Manufacturing Environment

• The product lifecycle starts with identifying a need based on market and customer demands
• From inception to completion, the product goes through the design and manufacturing processes
• Synthesis determines the product's philosophy, functionality, and uniqueness
• Analysis puts the conceptual design in the context of engineering sciences to evaluate performance

Manufacturing Industries

• Manufacturing industries can be classified according to:
  • Quantity of product made
  • Arrangement of physical facilities
  • Manufacturing automation

Types of Production

• Production activities classified by product quantity
  • Job shop production
  • Batch production
  • Mass production of discrete products
  • Continuous flow process

Job Shop Production

• Low-volume production
• Small manufacturing lot sizes
• Equipment is flexible and general-purpose
• Examples
  • Machine tools
  • Space vehicles
  • Aircraft

Batch Production

• Manufacturing of products in medium lots either once or at intervals
• Equipment is general purpose but designed for higher production rates
• Machine shops
  • Casting foundries
  • Plastic molding factories
  • Press working shops

Mass Production

• High volume production
• Equipment is dedicated to a particular product
• High demand rates
• Examples
  • Automobiles
  • Household appliances

Continuous Flow Production

• Continuous bulk manufacturing of large amounts of a product
• Examples
  • Chemical plants
  • Oil refineries

Types of Plant Layout

• Plant layout is the arrangement of physical facilities
• Three layout types:
  • Fixed position layout
  • Process layout
  • Product flow layout

Fixed Position Layout

• The product remains at one location due to size and weight
• Equipment and machinery are brought to the product
• Examples
  • Aircraft assembly
  • Shipbuilding

Process Layout

• Production machines are grouped by manufacturing process type
• Used in job shop and batch production

Product Flow Layout

• Plant facilities are arranged to produce one product or class of product in large volumes

Types of Automation

• Automation uses mechanical, electrical, electronic, and computer-based systems for production
• Three types
  • Fixed
  • Programmable
  • Flexible

Fixed Automation

• Sequence of processing operations is fixed by the equipment configuration
• High initial investment in custom-engineered equipment
• High production rates
• Limited flexibility
• Examples
  • Mechanized assembly lines
  • Machining transfer lines

Programmable Automation

• Production machinery can change its operation sequence for different products
• Operation sequence is controlled by a program
• High initial investment in general-purpose equipment
• Low production rates
• Flexibility to accommodate product changes
• Suited for batch production

Flexible Automation

• Can manufacture a variety of products or parts
• Features:
  • High initial investment for custom-engineered equipment
  • Continuous production of variable mixtures
  • Flexibility to accommodate changes
  • Suited for mass production

Applications of CAD/CAM

• CAD/CAM is vital in qualitative manufacturing
  • Geometric modeling
  • Design engineering analysis
  • Design evaluation and review
  • Manufacturing database creation
  • Computer-aided process planning (CAPP)
  • Interactive graphics NC part programming
  • Refined production planning
  • Material requirements planning (MRP)
  • Shop floor control
  • Computer-aided inspection and quality control