Computer Integrated Manufacturing (CIM) Lecturer: TRAN MANH SON Instructor: Dr. Tran Manh Son Email: sontm@hcmute.vn Phone: 0919 1971 39 Rules in Class Attend at least 80% of class hours Complete all home-works and assignments (If any) Assessment Assignment (50%) After each chapter will have one assignment/homework. Final Project (50%) Student have to complete a small project and present in the class. Textbook and References [1] Hệ thống sản xuất tích hợp, Đặng Thiện Ngôn, Lê Chí Cương.
[2] Automation Production System, and Computer Integrated Manufacturing, Mikell P. Groover, 2015 Sofware: Factory_IO Contents of This course Chapter 1: Introduction Chapter 2: Life Cycle of Product Chapter 3: Elements of CIM Chapter 4: Group Technology Layout Chapter 5: Computer Aided Process Planning Chapter 6: Product Data Management Chapter 7: Quality Management and Fault Diagnosis Chapter 8: Just-in-Time Manufacturing, Lean Manufacturing, and Agile Manufacturing. Chapter 3: Elements of CIM Contents of Chapter 3 3.1 Computer aided design – CAD 3.2 Computer aided manufacturing - CAM 3.3 Numerical Control NC/CNC 3.6 Flexible Manufacturing System – FMS 3.1 Computer aided design – CAD 3.1 Computer aided design – CAD 3.1 Computer aided design – CAD Manufacturing support system: procedures and system used to manage production and solve the technical and logistics problems associated with designing the products, planning, ordering materials, controlling work in process,… => CAD/CAM If the product design is good, another question is whether the product can be proceduced at low cost? The design contribute high rate to the cost of the product.1 Computer aided design – CAD The design process 3.1 Computer aided design – CAD Recognition of need: deficiency by an engineer/new product opportunity by a saleperson Problem definition: thorough specification of the item (physical, function, cost, quality, performance) Synthesis and analysis: conceptualized, analyzed, improved, resigned, analyzed again,… Evaluation: measuring the design against the specifications including assessment performance, quality, reliability,… Presentation: documenting the design by means of drawings, material specs, assembly lists,… 3.1 Computer aided design – CAD Computer-aided design (CAD): any design activity that involves the effective use of computer systems to create, modify, analyze, optimize, and document a design engineering. Geometric modelling: the use of a CAD system to develop a mathematical description of the geometry of an object (contained in computer memory) b.
Engineering analysis: some form of engineering analysis must be performed such as stress-strain, heat transfer, or dynamic simulation. Computer-aided engineering (CAE) offer: • Mass properties analysis: computation of features of a solid object as its volume, surface area, weight, and center of gravity.1 Computer aided design – CAD • Interference checking: CAD software examines 3-D geometric models consisting of multiple components to identify interferences between components • Tolerance analysis: to assess how the tolerances may affect the product’s function and performance, to determine how tolerances may influence the ease or difficulty of assembling the product, to assess how variations in component dimensions may affect the overall size of the assembly • Kinematic and dynamic analysis: Kinematic analysis studies the operation of mechanical linkages and analyzes their motions. Dynamic analysis extends kinematic analysis by including the effects of the mass of each linkage member and the resulting acceleration forces as well as any externally applied forces 3.1 Computer aided design – CAD c. Design Evaluation and Review: CAD features that are helpful in evaluating and reviewing a proposed design: • Automatic dimensioning: determine precise distance measures between surfaces on the geometric model • Error checking: used to review the accuracy and consistency of dimensions and tolerances • Plant layout design score: some software packages are available for facilities design, that is, designing floor layout, physical arrangement of equipment.
Also provide one or more numerical scores for each plant layout design, help to choose a proper one.1 Computer aided design – CAD d. Automated Drafting: CAD systems can be used to prepare highly accurate engineering drawings, on the other hand, increases productivity in the drafting function by about fivefold over manual preparation of drawings Advantages of CAD: Increase performance, reduce the time of synthesis, analysis Improve the quality of the design process Improve the quality of the design engineering documentation. Resulting from CAD system, the drawings are more standard, error-less and easier to read Provide the ability to set up database for production such as geometric, dimension, material,.of the product 3.2 Computer-Aided Manufacturing – CAM Computer-aided manufacturing (CAM) involves the effective use of computer technology in manufacturing planning and control, and can be divided into two categories: (1) manufacturing planning and (2) manufacturing control. Manufacturing planning: are those in which the computer is used directly to support the production function, but there is no direct connection between the computer and the process.
The computer is used to provide information for the effective planning and management of production activities. Some of important applications of this category: a. Computer-aided process planning (CAPP) - hoạch định quy trình sản xuất): is concerned with the preparation of route sheets that list the sequence of operations and work center required to produce the product and its components.2 Computer-Aided Manufacturing – CAM b. CAD/CAM NC part programming c.
Computerized machinability data systems: One of the problems with operating a metal cutting machine tool is determining the speeds and feeds that should be used for a given operation. Computer programs are available to recommend the appropriate cutting conditions for different materials and operations (e. Computerized work standards: The time study department has the responsibility for setting time standards on direct labor jobs performed in the factory. Establishing standards by direct time study can be a tedious and time-consuming task.
There are several commercially available computer packages for setting work standards. These computer programs use standard time data that have been developed for basic work elements that comprise any manual task. The program sums the times for the individual elements required to perform a new job in order to calculate the standard time for the job.2 Computer-Aided Manufacturing – CAM e. Cost estimating: The computer is programmed to apply the appropriate labor and overhead rates to the sequence of planned operations for the components of new products.
The program then adds up the individual component costs from the engineering bill of materials to determine the overall product cost f. Production and inventory planning: The production and inventory planning functions include maintenance of inventory records, automatic reordering of stock items when inventory is depleted, production scheduling, maintaining current priorities for the different production orders, material requirements planning, and capacity planning 3.2 Computer-Aided Manufacturing – CAM g. Computer-aided line balancing: Finding the best allocation of work elements among stations on an assembly line is a large and difficult problem if the line is of significant size 2. Manufacturing control: concerned with computer systems to control and manage the physical operations in the factory a.
Process monitoring and control: concerned with observing and regulating the production equipment and manufacturing processes in the plant b. Quality control: Quality control includes a variety of approaches to ensure the highest possible quality levels in the manufactured product 3.2 Computer-Aided Manufacturing – CAM c. Shop floor control: “Shop floor control” refers to production management techniques for collecting data from factory operations and using the data to help control production and inventory in the factory d. Inventory control: Inventory control is concerned with maintaining the most appropriate levels of inventory in the face of two opposing objectives: minimizing the investment and storage costs of holding inventory, and maximizing service to customers e.
Just-in-time production systems: Just-in-time (JIT) refers to a production system that is organized to deliver exactly the right number of each component to downstream workstations in the manufacturing sequence just at the time when that component is needed. JIT is one of the pillars of lean production 3.2 Computer-Aided Manufacturing – CAM Planning Control CAM Computer-aided Process monitoring process planning control CAD/CAM NC programing Quality control Computerized Shop floor control machinability data Computerized work Inventory control standards Cost estimating Just-in-time production Production and inventory planning Computer-aided line balancing 3.3 Computer Numerical Control (NC/CNC) 3.3 CNC Numerical control (NC): • Form of programmable automation in which mechanical actions of a machine tool or other equipment are controlled by a program containing coded alphanumeric data Application of NC: • Machine tool applications: drilling, milling, turning, and other metal working • Other applications: assembly, rapid prototyping, and inspection 3.1 Basic components: Part program is the set of detailed step-by-step commands that direct the actions of the processing equipment Machine control unit (MCU) is a Processing equipment: microcomputer storing the program of instructions and executes it by converting each command into mechanical actions of the processing equipment, one command at a time.3 CNC The CNC Machine Control Unit 3.3 CNC Controls for Machine Tool Axes and Spindle Speed: • Control the position and velocity (feed rate) of each machine axis • The rotational speed of the machine tool spindle Sequence Controls for Other Machine Tool Functions: • Coolant • Fixture clamping • Tool changer • Interlocks • emergency warnings 3.3 CNC Basic structure of CNC: 3.3 CNC Basic structure of CNC: 3.2 NC Coordinate Systems 3.2 NC Coordinate Systems • To program the NC processing equipment must define a standard axis system (the work head to the work part) Two axis systems used in NC: • Flat work parts • rotational parts. Coordinate systems are based on the Cartesian coordinates 3.2 NC Coordinate Systems Three linear axes (x, y, z) x- and y-axes are used to move and position the worktable z-axis is used to con- trol the vertical position of the cutting tool • Three rotational axes (a, b, c) • a-, b-, and c-rotational axes specify angular positions about the x-, y-, and z-axes 3.3 Motion Control Systems Motion Control Continuous Point-to-Point path 3.3 CNC Absolute Positioning the work head locations are always defined with respect to the origin of the axis system Incremental Positioning The next work head position is defined relative to the present location 3.4 CNC Software: interpret the NC part programs and generate the corresponding control signals CNC Software to drive the machine tool axes operating system software operate the communication machine interface soft- link between the CPU ware and the machine tool application software the NC part programs that are written for machining (or other) applications 3.5 Distributed Numerical Control 3.6 Machine Tool Applications Machining Operations and NC Machine Tools. Machining: manufacturing process in which the geometry of the work is produced by removing excess material Create a wide variety of shapes and surface finishes Relatively high production rates to yield Highly accurate parts Relatively low cost.6 Machine Tool Applications Four common types of machining operations: (a) turning (b) drilling 3.6 Machine Tool Applications Four common types of machining operations: (c) peripheral milling (d) surface grinding.6 Machine Tool Applications 3.6 Machine Tool Applications NC for Other Metalworking Processes (besides machining) Punch presses for sheet metal hole punching (đục) Presses for sheet metal bending (uốn) Welding machines Thermal cutting machines, such as oxy-fuel cutting, laser cutting, and plasma arc cutting Wire EDM: Electric discharge wire cutting operates 3.7 Advantages and Disadvantages of NC Advantages of NC.
• Nonproductive time is reduced • Greater accuracy and repeatability. • Inspection requirements are reduced. • More complex part geometries are possible. • Shorter manufacturing lead times • Reduced parts inventory.
• Less floor space. • Operator skill requirements are reduced.7 Advantages and Disadvantages of NC Disadvantages of NC. • Higher investment cost. • Higher maintenance effort.8 ANALYSIS OF POSITIONING SYSTEMS 3.8 ANALYSIS OF POSITIONING SYSTEMS Open-loop positioning system