Computer Aided Design And Manufacturing

ME8691 COMPUTER AIDED DESIGN AND MANUFACTURING

Manu Chandran Assistant professor School of mechanical engineering

UNIT I INTRODUCTION

Introduction to CAD CAM Computer Aided Drafting/Design: • Computer aided design is the technology concerned with the use of computer systems to assist the creation, modification, analysisi and optimization of design. • CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing. • CAD program/software is an electronic tool that enables you to make quick and accurate drawings with the use of a computer. • Computer drawings are neat, clean, highly presentable, and can be modified easily. • Computer-aided design (CAD) involves creating computer models defined by geometrical parameters.

• The models typically appear on a computer monitor as a threedimensional representation of a part or a system of parts, which can be readily altered by changing relevant parameters. • CAD software enables engineers and architects to design, inspect and manage engineering projects within an integrated graphical user interface. • CAD may be used to design curves and figures in two-dimensional (2D) space; or curves, surfaces, and solids in three-dimensional (3D) space. • CAD is mainly used for detailed engineering of 3D models or 2D drawings of physical components, but it is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components. • Furthermore, many CAD applications now offer advanced rendering and animation capabilities so engineers can better visualize their product designs

Computer-aided manufacturing (CAM): • Computer-aided manufacturing (CAM) uses geometrical design data to control automated machinery. • CAM systems are associated with computer numerical control (CNC) or direct numerical control (DNC) systems • Since both CAD and CAM use computer-based methods for encoding geometrical data, it is possible for the processes of design and manufacture to be highly integrated. • Computer-aided manufacturing (CAM) also known as Computer-aided Modeling or Computer-aided Machining is the use of software to control machine tools and related ones in the manufacturing of workpieces. • Its primary purpose is to create a faster production process and components and tooling with more precise dimensions and material consistency, which in some cases, uses only the required amount of raw material (thus minimizing waste), while simultaneously reducing energy consumption.

• CAM is a subsequent computer-aided process after computer-aided design (CAD) and sometimes computer-aided engineering (CAE), as the model generated in CAD and verified in CAE can be input into CAM software, which then controls the machine tool. • CAM reduces waste and energy for enhanced manufacturing and production efficiency via increased production speeds, raw material consistency and more precise tooling accuracy. • CAM also implements advanced productivity tools like simulation and optimization to leverage professional skills • CAM is often linked with CAD for more enhanced and streamlined manufacturing, efficient design and superior machinery automation. • The development of CAD and CAM and particularly the linkage between the two overcame traditional NC shortcomings in expense, ease of use, and speed by enabling the design and manufacture of a part to be undertaken using the same system of encoding geometrical data.

• CAD/CAM gave the designer much more direct control over the production process, creating the possibility of completely integrated design and manufacturing processes. Advantages: • There are also other reasons why a company might make a conversion from manual processes to CAD/CAM: – Increased productivity – Better quality – Better communication – Common database with manufacturing – Reduced prototype construction casts – Faster response to customers

• The emergence of CAD/CAM has had a major impact on manufacturing

Product cycle • The product begins with a need which is identified based on customers’ and markets’ demands. • The cycle through which the product goes from development to retirement is called product life cycle. • The product life cycle includes all activities starting from identification of product to deliver the finished product to the customer. • The product goes through two main processes from the idea conceptualization to the finished product: The design process and the manufacturing process. Design process: • The product cycle begins with the design process. • Synthesis and analysis are the two main sub processes of the design process

Synthesis: • The philosophy, functionality, and uniqueness of the product arc all determined during synthesis. • During synthesis, a design takes the form of sketches and layout drawings that show the relationship among the various product parts. These sketches and drawings can be created using a CAD/CAM system or simply hand-drawn on paper. • They are used during brainstorming discussions among various design teams and for presentation purposes. Analysis: • The analysis subprocess begins with an attempt to put the conceptual design into the context of engineering sciences to evaluate the performance of the expected product. • This requires design modeling and simulation. An important aspect of analysis is the "what if‘ questions that help us to eliminate multiple design choices and find the best solution to each design problem. • The outcome of analysis is the design documentation in the form of engineering drawings (also known as blueprints).

Manufacturing Process: • The manufacturing process begins with the process planning and ends with the actual product. • Process planning is considered the backbone or the manufacturing process since it attempts to determine the most efficient sequence in which to produce the product. • A process planner must be aware of the various aspects of manufacturing to plan properly. • The planner typically works with the blueprints and may communicate with the design team to clarify or request changes in the design to fit manufacturing requirements. • The outcome of the process planning is a production plan, tools procurement, material order, and machine programming. • Other special manufacturing needs such as design or jigs and fixtures or inspection gages are planned

Design process • Design is the human power to conceive, plan and realize products that serve human being in the accomplishment of any individual or collective purpose. • Design refers to the process of originating and developing a plan for a product, structure, sysytem or component. • The design progress is is a step by step manner from identification of need for the problem, a search for solution and development of chosen solution to manufacture and test. • The design process includes series of steps that engineers apply in making functional products and processes • The parts of the process often need to be repeated many times before production of a product can start. • The parts that get iterated and the number of such design cycles in any given project can be highly changeable.

Shingley Model: • It involves six steps

1. Recognition of need • Realization of problem exists in the design or in the product • Identification of some defect in a current machine design • New product opportunity 2. Definition of problem • Specification of the item to be designed • Functional characteristics, cost, quality, performance, etc. 3. Synthesis • Preliminary ideas are developed through research of similar product or designs in use 4. Analysis and Optimization • Suitability for the specified design constraints • If not suitable or design fails to satisfy the constraints • Then redesign or modified iteration continues until the proposed design meet the specifications (or) until feasibility is achieved

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Then components, sub-assemblies or sub-systems are then synthesized into the final overall system in a similar iterative manner. 5. Evaluation • Prototyping • Testing • Quality • Reliability testing 6. Presentation • Documentation of the design through drawings, material specifications, assembly lists, etc. Pahl and Beitz Model: 1. Clarification of the task: Collection of information, constraints on the design. 2. Conceptual design: establishment of the functions to be included in the design, 3. Embodiment design: problems are resolved and weak aspects are eliminated 4. Detail design: The dimensions, tolerance, materials and form of individual components of the design are specified in design for subsequent manufacturing

Sequential Engineering • Sequential engineering is the term used to explain the method of production in a linear system. • The various steps are done one after another, with all attention and resources focused on that single task. • Sequential engineering is a system by which a group within an organization works sequentially to create new products and services. • The sequential engineering is a linear product design process during which all stages of manufacturing operate in serial. • Both process and product design run in serial and take place in the different time • Process and Product are not matched to attain optimal matching • Decision making done by only group of experts

Sequential enginnerinng

Concurrent Engineering • In concurrent engineering, various tasks are handled at the same time, and not essentially in the standard order • This means that info found out later in the course can be added to earlier parts, improving them, and also saving time

• Concurrent engineering is a method by which several groups within an organization work simultaneously to create new products and services. • The concurrent engineering is a non- linear product design process during which all stages of manufacturing operate at the same time • Both product and process design run in parallel and take place in the same time. • Process and Product are coordinated to attain optimal matching of requirements for effective quality and delivery • Decision making involves full team involvement • It decreases product development time and also the time to market, leading to improved productivity and reduced costs. • Though initial implementation can be challenging, the competitive advantage means it is beneficial in the long term. • It removes the need to have multiple design reworks, by creating an environment for designing a product right the first time round.

Computer aided design • CAD is the intersection of Computer Graphics, Geometric modeling and Design tools • The concepts of computer graphics and geometric modeling and must be used innovatively to serve the design process • CAD is the function of computer systems to support in the creation, modification, analysis, or optimization of a design

• CAD software for design uses either vector-based graphics to explain the objects of traditional drafting, or may also develop raster graphics showing the overall look of designed objects. • During the manual drafting of engineering drawings, the output of CAD must convey information, like dimensions, materials, processes, and tolerances. • CAD is a significant industrial art used in many purposes, including industrial and architectural design, shipbuilding, automotive, and aerospace industries, and many more. • CAD is also extensively used to create computer animation for special effects in movies, and technical manuals, frequently called as Digital Content Creation. • CAD software packages provide the designer with a multi window environment with animation which is regularly used in Digital Content Creation. • The animations using wire frame modeling helps the designer to see into the interior of object and to observe the behaviors of the inner components of the assembly during the motion.

CAD Tools: • The CAD tools are mainly using for graphics applications and modeling. • Aids such a color, grids, geometric modifiers and group facilitate structural geometric models. • Visualization is achieved through shaded components and animation which focus design conceptualization, communication and interference detection. • Adding tolerances, tolerance analysis and investigating the effect of manufacturing on the design can perform by utilizing CAD tools. Uses of CAD: • CAD is one of the tools used by designers and engineers and is used in different ways depending on the profession of the customer and the type of software. • CAD is one of the Digital Product Development activities within the Product Lifecycle Management practices with other tools, which are either integrated modules or individual

• CAD is also used for the development of photo simulations that are frequently necessary in the preparation of Environmental Impact Reports • Parameters and constraints can be used to get the size, shape, and other properties of the modeling elements. • The features of the CAD system can be used for the several tools for measurement; such as yield strength, tensile strength and electrical or electro-magnetic properties CAD system architecture: • Computer architecture is a pattern describing how a group of software and hardware technolog standards relate to form a computer system. • In general, computer architecture refers to how a computer is designed and what technologies it is compatible with. • Computer architecture is likened to the art of shaping the needs of the technology, and developing a logical design and standards based on needs

• Computer architecture is a pattern describing how a group of software and hardware technology standards relate to form a computer system • Computer architecture is likened to the art of shaping the needs of the technology, and developing a logical design and standards based on needs. • it describes the capabilities of a computer and its programming method in a summary way, and how the internal organization of the system is designed and executed to meet the specified facilities. • Computer architecture engages different aspects, including instruction set architecture design, logic design, and implementation • An instruction set architecture is the interface between the software and hardware and also can be observed as the programmer's view of the machine • Computers do not understand high level languages, if any, language elements that translate directly into a machine's native op codes

Computer graphics • Computer Graphics is defined as creation, storage, and manipulation of pictures and drawings by means of a digital computer • It is an extremely effective medium for communication between people and computers • Computer graphics studies the manipulation of visual and geometric information using computational techniques • It focuses on the mathematical and computational foundations of image generation and processing rather than purely aesthetic issues

• In Interactive Computer Graphics (ICG) the user interacts with the compute and comprises the following important functions

• Modeling, which is concerned with the description of an object in terms of its spatial coordinates, lines, areas, edges, surfaces, and volume • Storage, which is concerned with the storage of the model in the memory of the computer • Manipulation, which is used in the construction of the model from basic primitives in combination with Boolean algebra

• Viewing, in the case the computer is used to look at the model from a specific angle and presents on its screen what it sees

Advantages: • The object drawing can be denoted by its geometric model in three dimensions. • Accurate drawings can be made • Sectional drawings can be easily created • Modification of geometric model is easy • Drawings can be reused Applications: • Illustration or design programs • Presentation graphics software • Animation software • Cad software • Image processing

Co-ordinate systems • Coordinate systems play an essential role in the graphics pipeline. • In general there are two types of coordinate systems such as cartesion and polar coordinate system. • In cartesian coordinate system the axis are represented by linear distances x,y,z and in polar coodinate sysytem uses angles. • In a 2-D coordinate system the X axis generally points from left to right, and the Y axis generally points from bottom to top. ( Although some windowing systems will have their Y coordinates going from top to bottom. ) • When we add the third coordinate, Z, we have a choice as to whether the Z-axis points into the screen or out of the screen:

Left and right handed coordinate system:

• Right Hand Coordinate System (RHS) Z is coming out of the page Counterclockwise rotations are positive if we rotate about the X axis : the rotation Y->Z is positive if we rotate about the Y axis : the rotation Z->X is positive if we rotate about the Z axis : the rotation X->Y is positive

• Left Hand Coordinate System (LHS) Z is going into the page Clockwise rotations are positive if we rotate about the X axis : the rotation Y->Z is positive if we rotate about the Y axis : the rotation Z->X is positive if we rotate about the Z axis : the rotation X->Y is positive • The important thing to note is what coordinate system is being used by the package you are working with, both for the creation of models and the displaying of them • Multiple Coordinate System: • In a typical graphics program, we may need to deal with a number of different coordinate systems, and a good part of the work ( and the cause of many headaches ) is the conversion of coordinates from one system to another.

• World Coordinate System - Also known as the "universe" or sometimes "model" coordinate system. This is the base reference system for the overall model, ( generally in 3D ), to which all other model coordinates relate. • Object Coordinate System - When each object is created in a modelling program, the modeller must pick some point to be the origin of that particular object, and the orientation of the object to a set of model axes • Hierarchical Coordinate Systems - Sometimes objects in a scene are arranged in a hierarchy, so that the "position" of one object in the hierarchy is relative to its parent in the hierarchy scheme, rather than to the world coordinate system • Viewpoint Coordinate System - Also known as the "camera" coordinate system. This coordinate system is based upon the viewpoint of the observer, and changes as they change their view. • Model Window Coordinate System - Not to be confused with desktop windowing systems ( MS Windows or X Windows ), this coordinate system refers to the subset of the overall model world that is to be displayed on the screen

2D and 3D transformations • A geometric transformation is an operation that modifies its shape, size, position, orientation etc. with respect to its current configuration operating on the vertices (position vectors). • Some of the important 2D transformations include: 1. Translation 2. Scaling 3. Rotation 4. Reflection 5. Shear 6. Twist

• 2D translation • Translation is nothing but moving an object across the screen from one position to another • The translation transformation positions the object to a new location. • The translation is accomplished by adding the coordinates of each corner point the distance through which the object is to moved

2D Rotation: • Rotation refers to the movement an object in such a way that the distance between a certain fixed point and any given point of that body remains constant • Rotation transformation techniques is commonly used in rendering and animation tehniques 2D Scaling: • Scaling is the transformation used to change, increase or decrease, the size of an object • Scaling can be achieved by multiplying the original coordinates of an object by the scaling factor Sx along xdirection and Sy along y-direction

• Scaling factor is always positive, if scaling factor is less than 1, the object is compressed; if more than 1, the object is stretched. 2D reflection: • Reflection is a transformation in which the direction of one axis is reversed • Reflection transformation produces a mirror image of an object • The reflection transformation is useful in the construction of symmetric objects. If the object is symmetric with respect to plane, only half of the geometry is created and then the half model is copied by reflection to develop the full model 3D transformation: • A three-dimensional object has a three-dimensional geometry, and therefore, it requires a three-dimensional coordinate transformation • A right handed coordinate system is used to carry out a 3-D transformation. • The scaling and translation transformations are essentially the same as twodimensional transformations

• However, the points matrix will have a non-zero 3rd column. Additionally, the transformation matrices contain some non-zero values inthe third row and third column. • Translation • In three-dimensional homogeneous coordinate representation, a point is transformed from position P(x,y,z) to P’= (x’,y’,z’) this can be written as: x’ = x+ tx y’ = y+ ty z’ = z+ tz Parallel to one of the Coordinate Axis • In special cases where an object is to be rotated about an axis that is parallel to one of the coordinate axis,

homogeneous coordinates • The rotation of a point, straight line or an entire image on the screen, about a point other than origin, is achieved by first moving the image until the point of rotation occupies the origin, then performing rotation, then finally moving the image to its original position. • The moving of an image from one place to another in a straight line is called a translation • . A translation may be done by adding or subtracting to each point, the amount, by which picture is required to be shifted. • translation of point by the change of coordinate cannot be combined with other transformation by using simple matrix application. • Such a combination is essential if we wish to rotate an image about a point other than origin by translation, rotation again translation.

• To combine these three transformations into a single transformation, homogeneous coordinates are used. • In homogeneous coordinate system, two-dimensional coordinate positions (x, y) are represented by triple-coordinates. • Homogeneous coordinates are generally used in design and construction applications. Here we perform translations, rotations, scaling to fit the picture into proper position • For two-dimensional geometric transformation, we can choose homogeneous parameter h to any non-zero value. • For our convenience take it as one. Each two-dimensional position is then represented with homogeneous coordinates (x, y, 1).

• Line drawing • A line connects two points. It is a basic element in graphics. To draw a line, it requires two points between which you can draw a line • Digital Differential Analyzer (DDA) algorithm is the simple line generation algorithm which is explained step by step here. • Step 1 − Get the input of two end points (X0,Y0)(X0,Y0) and (X1,Y1)(X1,Y1). • Step 2 − Calculate the difference between two end points. dx = X1 - X0 dy = Y1 - Y0 • Step 3 − Based on the calculated difference in step-2, you need to identify the number of steps to put pixel. If dx > dy, then you need more steps in x coordinate; otherwise in y coordinate.

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Step 4 − Calculate the increment in x coordinate and y coordinate. Xincrement = dx / (float) steps; Yincrement = dy / (float) steps; Step 5 − Put the pixel by successfully incrementing x and y coordinates accordingly and complete the drawing of the line Clipping: • Clipping is the process of determining the visible portions of a drawing lying within a window. In clipping each graphic element of the display is examined to determine whether or not it is completely inside the window, completely outside the window or crosses a window boundary. • Portions outside the boundary are not drawn • If the element of a drawing crosses the boundary the point of inter-section is determined and only portions which lie inside are drawn. Polygon clipping: • Convert a polygon into one or more polygons that form the intersection of the original with the clip window

viewing transformation: • The viewing transformation converts objects from their 3-dimensional camera-space coordinates into the appropriate 2-dimensional raster-space coordinates. • The camera coordinate system is a coordinate system with the camera at the origin, looking out over the positive z axis. • It is, essentially, the scene from the camera's point of view. The raster coordinate system is the space of the pixels on the monitor. • Connecting these two coordinate systems there is a special coordinate system known as the screen coordinate system • The screen coordinate system is, conceptually, the same as the film plane of a camera. • it is usually best to consider both the screen coordinate system and the raster coordinate system to be two-dimensional, even though we know that Render Man can output depth information. • the viewing transformation has lots of controls, but typically they are not all used together. Rather, a couple important controls are set and the rest are let to default to their “logical” values.

Brief introduction to CAD and CAM • CAD/CAM is a term which means computer-aided design and computeraided manufacturing. • It is the technology concerned with the use of digital computers to perform certain functions in design and production • This technology is moving in the direction of greater integration of design and manufacturing, two activities which have traditionally been treated as distinct and separate functions in a production firm. • Ultimately, CAD/CAM will provide the technology base for the computerintegrated factory of the future. • Computerassistancewhileadesignerconvertshisorherideasandknowledgein toamathematicalandgraphicalmodelrepresentedinacomputer. • Use of computers systems to plan, manage and control the operations of a manufacturing plant through either direct or indirect computer interface with plant’s production resources

• CAD/CAM involves all the processes of conceptualizing , designing, analyzing, prototyping and actual manufacturing with computer’s assistance • Latest techniques of geometric modeling (Feature base or parametric modeling) and manufacturing like rapid prototyping (RP) have bridged the gap between product conceptualization and product realization • CAD/CAMKeytoimprovemanufacturingproductivityandthebestapproachformeetingth ecriticaldesignrequirements • CAD/CAMsoftwareprovidesengineerswiththetoolsneededtoperformtheirte chnicaljobsefficientlyandfreethemfromthetediousandtimeconsumingtasksthatrequirelittleornotechnicalexpertise. • CAD/CAMsoftwarespeedsthedesignprocess,thereforeincreasingproductivit y,innovationandcreativityofdesigners • CAD/CAMistheonlymeantomeetthenewtechnologicaldesignandproduction requirementsofincreasedaccuracyanduniformity

Manufacturing Planning: • Planning is an essential part of every manufacturer’s life and the key to effective inventory and resource management. • even engineer-to-order and lean make-to-order manufacturers must plan for materials and resources (equipment, capacity, people/skills) to be available to satisfy customer requirements. • Manufacturing planning is a coordinated process involving demand management, forecasting, master scheduling, material planning (MRP), and capacity planning, fully integrated with operational management applications including production control, inventory management, and procurement. • Planning is all about turning customer demand, a combination of real orders and forecasted demand, into production schedules and planned purchases mapped out in time to assure that the materials, parts and products are available when needed but only in the quantity needed and at the time needed to keep the plant operating efficiently with minimal excess inventory.

• Execution applications – in production and purchasing – ensure that all activities are coordinated and work is completed on time, maximizing the efficient use of resources. • The result is on-time shipment, happy customers, and minimal costs. This coordinated planning and execution ‘closed loop’ also keeps things coordinated in the face of changing demand, unexpected disruptions and other challenges Manufacturing control : • Material requirement planning and netting • Manage your production and your purchases according to the Material Requirement Planning and Netting. • Synoptic ERP takes into account the expressed requisitions and the situation of the inventory before suggesting new manufactures or purchases demands. • You can customize the material requirement planning and choose between automation and proposal of actions to lead.

• Planning and scheduling • Synoptic ERP integrates functions for forward planning of infinite loading. The load schedule is a powerful tool of macro planning that allows you to visualize the loading and the capacity of resources. • The function of scheduling as exact as possible is achieved thanks to critical ratio (parameterizable according to your business). • Graphical reports concerning the progress and the delay of production enable you to be proactive and to meet the deadlines. • Data acquisition in workshop • Synoptic ERP offers a real-time tool for data acquisition in workshop. Thanks to bar-code readers or to touch-sensitive screens, you control in real-time the counting concerning the manufacturing: past time on manufacturing, number of manufactured parts, quantity of scrap, reason and duration of stopping..

Recovering of data on lines of production • It's possible to interface Synoptic ERP with the machines of production. You can automatically regain the following data: real past time, manufactured quantity, quantity of scrap, duration of stopping, Overall Equipment Effectiveness (OEE). Introduction to CAD/CAM: • Throughout the history of our industrial society, many inventions have been patented and whole new technologies have evolved • Perhaps the single development that has impacted manufacturing more quickly and significantly than any previous technology is the digital computer • Computer-aided design(CAD) is defined as the application of computers and graphics software to aid or enhance the product design from conceptualization to documentation

• CAD is most commonly associated with the use of an interactive computer graphics system, referred to as a CAD system. Computer-aided design systems are powerful tools and in the mechanical design and geometric modeling of products and components • There are several good reasons for using a CAD system to support the engineering design function: • To increase the productivity • To improve the quality of the design • To uniform design standards • To create a manufacturing data base • To eliminate inaccuracies caused by hand-copying of drawings and inconsistency between drawings

• Computer-aided manufacturing(CAM) is defined as the effective use computer technology in manufacturing planning and control • CAM is most closely associated with functions in manufacturing engineering, such as process and production planning, machining, scheduling, management, quality control, and numerical control(NC) part programming • Computer-aided design and computer-aided manufacturing are often combined CAD/CAM systems • This combination allows the transfer of information from the design into the stage of planning for the manufacturing of a product, without the need to reenter the data on part geometry manually • The database developed during CAD is stored; then it is processed further, by CAM, into the necessary data and instructions for operating and controlling production machinery, materialhandling equipment, and automated testing and inspection for product quality

CAD/CAM concepts : CAD/CAM Software • Software allows the human user to turn a hardware configuration into a powerful design and manufacturing system. CAD/CAM software falls into two broad categories,2-D and 3-D, based on the number of dimensions are called 2-D representations of 3-D objects is inherently confusing. • Equally problem has been the inability of manufacturing personnel to properly read and interpret complicated 2-D representations of objects. • 3-D software permits the parts to be viewed with the 3-D planesheight,width, and depth-visible. The trend in CAD/CAM is toward 3-D representation of graphic images. • Such representation approximate the actual shape and appearance of the object to be produced; therefore, they are easier to read and understand.

• CAD/CAM Hardware: • The hardware part of a CAD/CAM system consists of the following components ⑴ one or mare design workstations, ⑵ digital computer, ⑶ plotters and other output devices, and⑷ storage devices. • In addition, the CAD/CAM system would have a communicatio interface to permit transmission of data to and from other computer systems, thus enabling some of the benefits of computer integration • The workstation is the interface between computer and user in the CAD system.The design of the CAD workstation and its available features have an important influence on the convenience • The workstation must include a digital computer with a high-speed control processing unit(CPU). It contains require a and logic/arithmetic section for the system • The most widely used secondary storage medium in CAD/CAM is the hard disk, floppy diskette, or a combination of both

Applications of CAD/CAM: • The emergence of CAD/CAM has had a major impact on manufacturing, by standardizing product development and by reducing design effort, tryout, and prototype work; it has made possible significantly reduced costs and improved productivity. • Programming for NC, CNC, and industrial robots; • Design of dies and molds for casting • Design of tools and fixtures and EDM electrodes • Process planning and scheduling

• There are 4 different types of productions which are most commonly used. • Which type of production should be used by the company depends on the type of product being manufactured, the demand of the product as well as the supply of raw materials. • Taking these factors into consideration, below are the 4 types of Production. 1) Unit or Job type of production: • This type of production is most commonly observed when you produce one single unit of a product 2) Batch type of Production • It is one of the types of production most commonly used in consumer durables, FMCG or other such industries where there are large variety of products with variable demands. • Batch production takes place in batches. The manufacturer already knows the number of units he needs to a manufacturer and they are manufactured in one batch.

3) Mass Production or Flow production: • Mass production is also known as flow production or assembly line production. It is one of the most common types of products used in the automobile industry and is also used in industries where continuous production is required. • An Assembly line or mass production plant typically focus on specialization. There are multiple workstations installed and the assembly line goes through all the workstations turn by turn. • The work is done in a specialized manner and each workstation is responsible for one single type of work 4) Continuous production or Process production: • There is a lot of confusion between mass production and continuous production. It can be differentiated by a single element. The amount of mechanical work involved. • In Mass production, both machines and humans work in tandem. However, in continuous production, most of the work is done by machines rather than humans. • In continuous production, the production is continuous,24×7 hours, all days in a year.

Manufacturing models and Metrics : Production Concepts and Mathematical Models • Production rate, Rp • Production capacity, PC • Utilization, U • Availability, A • Manufacturing lead time, MLT • Work-in-progress, WIP • Operation Cycle Time Typical cycle time for a production operation: • Tc = To + Th + Tth • where, Tc = cycle time • To = processing time for the operation. • Th = handling time (e.g. loading and unloading the production • machine). • Tth = tool handling time (e.g. time to change tools).

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Production Rate Batch production: batch time Tb = Tsu + QTc Average production time per work unit Tp = Tb / Q Production rate, Rp = 60/ Tp (pieces/hr) Utilization and Availability Utilization: where Q = Quantity actually produced and PC = plant capacity Availability: Where, MTBF = Mean time between failures and MTTR = mean time to repair Availability - MTBF and MTTR Defined

Mathematical models of Production Performance

• Manufacturing lead time • divide the activities in production into two main categories, operations and non operation elements. • An operation on a product (or work part) takes place when it is at the production machine. • The non operation elements are the handling, storage, inspections, and other sources of delay • A setup procedure is generally required to prepare each production machine for the particular product. The setup typically includes arranging the workplace and installing the tooling and fixturing required for the product.

• Production rate: • The production rate for an individual manufacturing process or assembly operation is usually expressed as an hourly rate • The rate will be symbolized as Rp. Again we will begin with the batch production case and then generalize to the job shop and mass-production cases. • Components of the operation time: • The operation time is the time an individual work part spends on a machine, but not all of this time is productive • . Operation time for a machining operation is composed of three elements : the actual machining time Tm the workpiece handling time Th and any tool handling time per workpiece Tth • The tool handling time represents all the time spent in changing tools when they wear out, changing from one tool to the next for successive operations performed on a turret lathe, changing between the drill bit and tap in a drill-and-tap sequence performed at one drill press, and so on.

• Capacity: • The term capacity, or plant capacity, is used to define the maximum rate of output that a plant (or other production facility) is able to produce under a given set of assumed operating conditions. It is closely related to production rate • Capacity for a production plant is usually measured in terms of the types of output produced by the plant • Quantitative measures of plant capacity can be developed based on the production models derived earlier • Utilization and availability: • The term availability is sometimes used as a measure of reliability for equipment. It is especially germane for automated production equipment. Availability is defined using two other reliability terms, the mean time between failures (MTBF) and the mean time to repair (MTTR)

• Work-in-process Work-in-process (WIP) is the amount of product currently located in the factory that is either being processed or is tween processing operations. WIP is inventory that is in the state of being transformed from raw material to finished product.