Introduction to CNC (Computer Numerical Control) Machine

Introduction to CNC (Computer Numerical Control)

1. Computer Numerical Control (CNC) UNIT II CIM 1 Data Integration Syllabus: Introduction to CNC Name: Jeetendra Dhamone Email id : [email protected] Mob. No: 8951834155

2. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 2 Massachusetts Institute of Technology (MIT, USA) is credited with pioneering the development in both CAD and CAM. Design and manufacturing requirements of aerospace industries after the Second World. Late 40‟sand early 50‟s could not meet the design and manufacturing challenges Develop sophisticated aircraft and satellite launch vehicles The first major innovation in machine control is the Numerical Control (NC), demonstrated at MIT in 1952. NC machines used paper tape as an input medium Second-generation models replaced the vacuum tubes with transistors Third-generation models featuring integrated circuitry and modular circuit Special preprogrammed circuit boards In mild 60 th Direct Numerical Control (DNC)as the computer bypassed the tape reader By late 60‟s mini computers [email protected] Mob. No: 8951834155

3. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 3 [email protected] Mob. No: 8951834155

4. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 4 [email protected] Mob. No: 8951834155 A CNC (computer numerical control) machine is a computer-controlled automated tool that can be used to shape various materials like metals, plastic, or wood based on a set of instructions generated through CAM (computer-aided manufacturing) software. There are two commonly used CNC machines: CNC lathes and CNC mills. CNC Machine Working: Step-by-Step Program Creation:  A G-code or M-code is created using CAD/CAM software. This includes coordinates, speeds, feeds, and tool paths. Input to MCU:  The program is fed into the Machine Control Unit. The MCU of the CNC machine interprets instructions into electrical signals. Actuation:  The signals drive motors and actuators. The tool and table move according to pre-defined instructions. Tool Engagement:  The spindle spins the cutting tool. The workpiece is shaped through milling, drilling, or turning. Feedback and Correction:  Sensors send real-time position data back to the MCU. Adjustments are made on the fly to maintain accuracy. Completion and Repeatability:  Once the operation is complete, the CNC machine resets or moves to the next instruction.

5. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 5 [email protected] Mob. No: 8951834155 CNC milling machine CNC lathe CNC drilling machine CNC laser cutting machine CNC grinder CNC water jet cutting machine CNC plasma cutting machine CNC electrical discharge machine CNC Milling Machine 1. Input Device CNC programs are loaded into the machine. 2. Machine Control Unit (MCU)  https://www.xometry.com/resources/machining/parts-of-a-cnc-machine/

6. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 6 [email protected] Mob. No: 8951834155 3. Machine Tools  4. Driving System In a traditional CNC mill, the bed moves horizontally (along the x- and y-axes), and the tool goes up and down (z-axis). In a CNC lathe, the tool moves in the same direction as the rotating workpiece, and goes to the outer edge as it rotates instead of across the part. 5. Feedback System 6. Display Unit 7 . Headstock The headstock is found on the left side of a CNC lathe. It houses the main drive, bearings, and gears that spin the chuck. It’s enclosed, but it can be accessed by removing some inspection panels.

7. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 7 [email protected] Mob. No: 8951834155 8 . Bed 9. Tailstock & Chuck 10. Control Panel This is basically the brain of the machine. It houses the input device, the display unit, the keyboard, and other control buttons. It’s typically attached to the machine but on an extendable arm so you can pull it toward you or position it where you need it.

8. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 8 [email protected] Mob. No: 8951834155 What is Part Programming Part Programming is the creation of a sequence of instructions for NC/CNC (Numerical Control/Computer Numerical Control) machines to produce a specific component. These programs, originally written on punched tapes but now as digital files, use standard codes and  coordinate systems  to direct tool movements, spindle speeds, and other operations. Key Aspects of Part Programming A part program is a list of commands, including the Sequence Number (N) Preparatory Function (G), Dimensional Words (X, Y, Z) Feed Rate (F) Spindle Speed (S) And Miscellaneous Functions (M) Feed Rate (F) is  the speed at which a cutting tool moves into the material during a machining operation, measured in units of distance per minute (e.g., mm/min) or per spindle revolution (e.g., mm/rev) Spindle speed The rotational speed of the spindle, typically measured in revolutions per minute (RPM).

9. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 9 [email protected] Mob. No: 8951834155 Codes : G-codes (Preparatory Functions) : Define the type of motion, like linear (G01) or circular (G02/G03).  M-codes (Miscellaneous Functions) : Control machine actions like M03 (spindle on clockwise) or M06 (tool change).  A preparatory function, or  G-code , is a command in Computer Numerical Control (CNC) programming that tells a machine tool what specific type of operation or mode to enter before a task can be performed.  Miscellaneous functions refers to  a broad category of programming commands and functions that perform various auxiliary operations, control system components, or handle tasks that don't fit into a specific, predefined category M00: Program Stop  - Halts the program execution until the operator restarts it.  M01: Optional Program Stop  - Halts the program if the optional stop switch is activated.  M02: Program End  - Ends the current program.  M03: Spindle ON Clockwise (CW)  - Starts the spindle rotating in a clockwise direction.  M04: Spindle ON Counterclockwise (CCW)  - Starts the spindle rotating in a counterclockwise direction.  M05: Spindle Stop  - Stops the spindle from rotating.  M06: Tool Change  - Initiates the automatic tool changing process.  M08: Coolant ON  - Turns the coolant on.  M09: Coolant OFF  - Turns the coolant off. 

10. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 10 [email protected] Mob. No: 8951834155 Common G-Code Functions Motion Commands: G00:  Rapid positioning.  G01:  Linear interpolation with a specified feed rate.  G02:  Clockwise circular or helical interpolation.  G03:  Counter-clockwise circular or helical interpolation.  G04:  Dwell (pause) for a specified time.  Plane and Unit Selection: G17:  Select the XY plane for operation.  G18:  Select the XZ plane for operation.  G19:  Select the YZ plane for operation.  G20:  Use imperial units (inches).  G21:  Use metric units (millimeters).  Tool Compensation and Coordinate Systems: G40:  Cancel cutter compensation.  G41:  Start cutter compensation to the left.  G42:  Start cutter compensation to the right.  G43:  Apply tool length compensation (plus direction).  G49:  Cancel tool length compensation.  G53:  Use the machine coordinate system.  G54-G59:  Select a preset work coordinate system (1 through 6).  Canned Cycles: G80:  Cancel any active canned cycle.  G81:  Standard drilling cycle.  G82:  Drilling cycle with a dwell.  G83:  Peck drilling cycle.  G84:  Right-hand tapping cycle.  Programming System Absolute system Incremental System An "absolute system" can refer to  a coordinate system with a single fixed origin, a system of measurement units based on fundamental physical constants (like cgs or SI units), or a system of equations involving an absolute value function An incremental system develops software or projects in small, repeated cycles (increments) instead of a single, massive release, allowing for early feedback, flexibility, and the gradual addition of features. 

11. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 11 [email protected] Mob. No: 8951834155

12. Computer Numerical Control Prof. Jeetendra Dhamone UNIT I CIM 12 [email protected] Mob. No: 8951834155