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PROCESS PLANNING AND COST ESTIMATION

by Anna SuperkingsAnna Superkings
Type: NoteInstitute: Anna university Offline Downloads: 18Views: 891Uploaded: 4 months ago

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Anna Superkings
Anna Superkings
Fatima Michael College of Engineering & Technology FATIMA MICHAEL COLLEGE OF ENGINEERING & TECHNOLOGY Madurai -625 020 An ISO 9001:2008 Certified Institution Senkottai Village, Madurai – Sivagangai Main Road, ME6005-PROCESS PLANNING AND COST ESTIMAION COURSE MATERIL UNIT 1 INTRODUCTION TO PROCESS PLANNING PROCESS PLANNING Process planning is a detailed specification which lists the operation, tools, and facilities Usually accomplished in manufacturing department Also known as operations planning Systematic determination of the engineering processes and systems to manufacture a product competitively and economically DEFINITION Process planning can be defined as an act of preparing a detailed processing documentation for the manufacture of a piece part or assembly METHIDS OF PROCESS PLANNING 1. Manual Process planning 2. Computer Aided Process planning (CAPP) a. Retrieval CAPP system b. Generative CAPP system MANUAL PROCESS PLANNING Manually prepared Task involves examining and interrupting engineering drawings, making decisions on machining process selection, equipment selection, operation sequence, and shop practices Dependent on judgment and experience of process planner Advantages Very much suitable for small scale companies Highly flexible Low investment costs Disadvantages Very complex Time consuming Requires large amount of data Fatima Michael College of Engineering & Technology
Fatima Michael College of Engineering & Technology Requires skilled process planner More possibilities for human error Increases paper work Inconsistent process plans results in reduced productivity COMPUTER AIDED PROCESS PLANNING (CAPP) To overcome drawbacks of manual process planning Computer Aided Process planning (CAPP) is used Provides interface between CAD and CAM Benefits Process rationalization and standardization Productivity improvement Product cost reduction Elimination of human error Reduction in time Reduced clerical effort and paper work Improved legibility Faster response to engineering changes Incorporation of other application programs RETRIEVAL CAPP SYSTEM It is also called as variant CAPP, widely used in machining applications Basic idea behind is, similar parts will have similar process plans Process plan for new part is created by recalling, identifying and retrieving an existing plan for a similar part, and making necessary modification for new part PROCEDURE FOR RETRIEVAL CAPP SYSTEM Retrieval CAPP system is based on principles of group technology (GT) and part classification and coding For each part family, standard process plan is prepared and stored in computer files Through classification and coding, code number is generated Standard plan is retrieved and edited for new part Advantages Once a standard plan has been written, variety of parts can be planned Requires simple programming and installation Understandable, and planner has control of final plan Easy to learn and easy to use Disadvantages Components to be planned are limited to similar components previously planned Requires experienced process planners to modify the standard plan for specific component Fatima Michael College of Engineering & Technology
Fatima Michael College of Engineering & Technology New part design Derive GT code number for part Preparatory storage Search part family file for GT code number Select coding system and form part families Part family file Retrieve standard Standard Process plan Prepare standard process plan file process plans for part families Edit existing plan or write new plan rocess plan formatter Other applications such as cost estimating and work standards (Route sheet) Process plan Fatima Michael College of Engineering & Technology
Fatima Michael College of Engineering & Technology GENERATIVE CAPP SYSTEM In this approach computer is used to synthesize or generate each individual process plan automatically without reference to any prior plan Generates the process plan based on decision logics and pre-coded algorithms. Computer stores the rules of manufacturing and equipment capabilities Specific process plan for specific part can be generated without any involvement of process planner Components of Generative CAPP system Part descriptor Subsystem to identify machine parameters Subsystem to select and sequence individual operations Database Report generator Advantages Generate consistent process plan rapidly New components can be planned as easily as existing components It has potential for integrating with automated manufacturing facility to provide detailed control information Drawbacks Complex and very difficult to develop 1.0 WORK STUDY First technique applied for increasing productivity. Considered as a valuable tool in increasing productivity. Definition: Work study is a generic term for the techniques of method study and work measurement. These techniques are used in the examination of human work in all its contexts. They lead systematically to the investigation of all the factors which affect the efficiency and economy at the work place in order to affect improvement. 1.1.METHOD STUDY Method study is the technique of systematic recording and critical examination of existing and proposed ways of doing work and developing an easier and economical method. 1.1.1 Objectives of Method Study 1. Improvement of manufacturing processes and procedures. Fatima Michael College of Engineering & Technology

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