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Advanced manufacturing process (ME F315) Department of Mechanical Engineering BITS Pilani K. K. Birla Goa campus Instructor in charge: Dr. Biswajit Das Office No.- E107 Tel...

Advanced manufacturing process (ME F315) Department of Mechanical Engineering BITS Pilani K. K. Birla Goa campus Instructor in charge: Dr. Biswajit Das Office No.- E107 Tel: +91-832-2580381 (O) BITS Pilani K. K. Birla Goa campus Dr. Manoj Kumar Pandey Objective of the Course: The objective of the course is to provide students: To look beyond conventional manufacturing processes. To learn details of automated machine tools like CNC, and learn CNC part programming. To learn fundamentals and modelling aspects of unconventional machining processes. To familiarize the students with the basic concepts of additive manufacturing and micromachining processes. To familiarize the students with basic pneumatic circuits used in daily life applications. To expose students to new materials used in manufacturing industry along with cutting edge characterization techniques. Learning outcomes: Upon completing the course students will be able to: Understand basic operations of NC, CNC, DNC Can write part program for a given geometry in the CNC machine tool Can understand process details and modelling aspects of non traditional machining processes Will be able to understand and form basic pneumatic circuits Will be exposed to industry relevant materials along with cutting edge characterization instruments. Dr. Manoj Kumar Pandey Industrial Revolution Building blocks of Industry 4.0 Cost Comparison https://www.pac.gr/bcm/uploads/industry-4-0-deloitte-study.pdf Sensorized manufacturing environment  This will permit to assess the worker’s state across multiple dimensions, including satisfaction, engagement, stress level, capabilities, skill, performance and experience.  Motion sensors can detect movement and gestures that contribute to the definition of the psychophysiological status. Through wearable devices, workers receive the support to bridge cognitive gaps they are experiencing.  Examples of captured parameters are: breath/ heart rate, skin conductance and movement of relevant body segments. Future Smart Factory  Manufacturing-A quick recap Manufacturing is a value addition process in which raw materials of low utility and value are converted into high utility and valued products with definite dimensions, forms and finish imparting some functionality. Ex: A lump of mild steel has no value or use but after going through suitable manufacturing process it becomes a bolt. This bolt is useful product. Dr. Manoj Kumar Pandey  Manufacturing-A quick recap Dr. Manoj Kumar Pandey  Machining-A quick recap Definition: Machining is an essential process of finishing by which jobs are produced to the desired dimensions and surface finish by gradually removing the excess material from the preformed blank in the form of chips with the help of cutting tool(s) moved past the work surface(s). Requirements of Machining Dr. Manoj Kumar Pandey Historical development of machine tools 15th century: Metal machining 18th century: Industrialization 20th century: F.W. Taylor-Tool material HSS Automated production equipment Screw machines Transfer lines Assembly line Using cams and preset stops Programmable automation NC/CNC PLC Robots Dr. Manoj Kumar Pandey  Configuration and kinematic structure of lathe Centre lathe 15  Configuration and kinematic structure of lathe Centre lathe 16 Historical notes on Numerical control (NC) machine tool Developed by US Air Force in the year 1948. The first work is attributed to Parsons Corporation and the system is called “Cardamatic milling machine”. The work later (1951) undertaken by MIT. J. T. Parsons-Father of NC In 1956, MIT demonstrated CNC and in 1958 developed APT Language. Dr. Manoj Kumar Pandey Thank you for your patience 18  Advanced manufacturing processes (ME F315) Department of Mechanical Engineering BITS Pilani K. K. Birla Goa campus Instructor in charge: Dr. Biswajit Das Office No.- E107 Tel: +91-832-2580381 (O) BITS Pilani K. K. Birla Goa campus Dr. Manoj Kumar Pandey What is a CNC program? A CNC program is a sequence of commands, written, in a suitable language meant for controlling the operations of the machine By execution, it makes a machine tool carry out some motions and auxiliary operations As a result, part is produced from a blank There are other operations also apart from machining successfully controlled by CNC program execution Dr. Manoj Kumar Pandey Part program structure Part program contains set of blocks Each block contains words Each word is a collection of characters used to form an instruction The structure of block is given as Dr. Manoj Kumar Pandey Example of a typical command N006 G90 G00 X20 X30 N007 Y50 N008 G01 X100 Y100 F200 N009 G02 X140 R30 N010 M30 Dr. Manoj Kumar Pandey  Few points regarding CNC 1. Motion control: Point to point (PTP) Continuous (contouring) path 2. Control loops: Open loop Closed loop 3. Positioning systems: Incremental Absolute positioning 5. Number of Axes 3-axis 5-axis  Point-to-Point Tool Movements Point-to-point control systems cause the tool to move to a point on the part and execute an operation at that point only. The tool is not in continuous contact with the part while it is moving. Drilling, reaming, punching, boring and tapping are examples of point- to-point operations.  Continuous-Path Tool Movements Continuous-path controllers cause the tool to maintain continuous contact with the part as the tool cuts a contour shape. Operations include milling along any lines, at any angle, milling arcs & lathe turning.  Loop Systems for Controlling Tool Movement Open Loop System Uses stepper motor to create movement. Motors rotate a fixed amount for each pulse received from the MCU. The motor sends a signal back indicating that the movement is completed. No feedback to check how close the actual machine movement comes to the exact movement programmed.  Loop Systems for Controlling Tool Movement Closed Loop System AC, DC, and hydraulic servo-motors are used. The speed of these motors are variable and controlled by the amount of current or fluid. The motors are connect to the spindle and the table. A position sensor continuously monitors the movement and sends back a signal to Comparator to make adjustments.  Absolute and Incremental Positioning From the current position to next position: Absolute positioning Incremental positioning Move is: x = 40, y = 50 Move is: x = 20, y = 30 Sequence of the words in an NC block Lathe – Coordinate system Diameter and radius programming Lathe - Turning Lathe - Turning Lathe - Facing Thank you for your patience 24  Advanced manufacturing processes (ME F315) Department of Mechanical Engineering BITS Pilani K. K. Birla Goa campus Instructor in charge: Dr. Biswajit Das Office No.- E107 Tel: +91-832-2580381 (O) BITS Pilani K. K. Birla Goa campus Dr. Manoj Kumar Pandey  Why Canned cycles? Canned cycle This is a typical operation that can be executed with only one command instead of programming a series of individual cutting movement. Canned cycles combine many programming operations They are written to reduce the program length, minimize mathematical calculations, and utilize minimal tool motions. Examples: drilling, peck drilling, tapping, boring, back spot The advantages of writing a part program with these structures are: To reduce length of part program. To minimize the time required to develop a program. Easy to detect error in the part program. It is possible not to write same instructions again and again in the program. Memory requirement is less in the control unit.  Canned cycles for lathe Canned cycles for lathe: G71-Turning cycle for rough cut G70-Turning cycle for finishing operation G72-Facing cycle G73-Pattern repeating cycle G75-Grooving cycle G76-Threading cycle G80-Cancel all canned cycles  G71-Canned cycle for lathe Block Parameter Description First block U Depth of cut G71 cycle is used for rough material removal in a CNC R Retract height lathe. Second block P Contour start CNC operator can control block number following parameters: Q Contour end block Depth of cut number U Finishing Retract height allowances in X- Finishing allowance in x and z axis axis W Finishing Cycle cutting feed, spindle allowances in Z- speed axis Programming syntax F Feed rate during G71 cycle G71 U….R… S Spindle speed G71 P…Q…U….W…F…S during G71 cycle  G71-Canned cycle for lathe Initial tool motion Final tool motion 1 – Tool will move in x-axis U (depth of cut) deep with 5 – Tool rapidly moves to last cut depth. programmed feed from starting-point. 6 – Tool moves with feed in x-axis U deep (first- 2 – Tool will travel with feed in z-axis (destination point block U depth of cut). in z-axis is given in P Q blocks ) 7 – Tool with feed moves in z-axis (destination point 3 – Tool rapidly retracts R amount in both x-axis and z- given in P Q blocks). axis (at 45 degrees). 8 – Tool rapidly retracts in x-axis and z-axis R 4 – Tool rapidly travel in z-axis to start-point amount (45 degrees).. 9 – Tool rapidly moves to start-point only in z-axis  G71-Canned cycle for turning in lathe Program N50 G00 X106 Z5 M3 S800 N60 G71 U10 R 10 N70 G71 P80 Q90 U0 W0 F0.25 N80 G01 X60 N90 G01 Z-75 G70 finishing cycle can be called at the end for finishing Lathe – Canned Cycle Lathe – Canned Cycle Thank you for your patience 9