COMPUTER INTEGRATED MANUFACTURING SYSTEMS LAB MANUAL

(MCE-451)

ME 7 th SEMESTER

YADAVINDRA COLLEGE OF ENGINEERING

MECHANICAL ENGINEERING DEPARTMENT

2014

MCE 451 COMPUTER INTEGRATED MANUFACTURING SYSTEMS LAB

L T P Credits

0 0 2 1.0

List of Experiments

General Overview

1 Study of CNC Lathes and Milling machines: Advantages over ordinary machines with reference to control of cutting speed and profile cutting etc.

2 Study of Robots. Applicability for various operations.

3 Study of various types of cutting tools for turning & milling (HSS, brazed carbide, carbide indexable inserts and solid carbide tools) viz. tools for turning & boring; milling cutters of plano, bull and ball-nose type and their uses.

Manual Part Programming

4 Entering M-codes for spindle start/stop, coolant start/stop etc.

5 Entering G-codes for straight and taper-turning operations.

6 Entering codes for cutting along concave and convex arcs; Radius compensation.

Use of Software for CNC Programming & Tool Path Simulation:

7 Entering specifications for various types of tools (viz. end-mill, ball-mill or bull-nose tools) for programming.

8 Use of various types of tool entry options (ramp/helical) for safe and smooth start of cut.

9 Application of profile and copy-milling operations for die-cutting.

10 Machining simulation for tool path visualization.

11 NC post processing to transfer part programs to CNC machines for actual machining.

Introduction to Finite Element Analysis:

12 Practical considerations while making models for FEA.

13 Defining supports and loads for FEA.

14 Meshing: Various types of mesh elements and their uses. Mesh-refining.

15 Solving and post-processing the solution to display results in the desired manner.

Experiment -1

AIM:-Study of CNC Lathes and Milling machines: Advantages over ordinary machines with reference to control of cutting speed and profile cutting etc.

APPARATUS:- CNC Lathe Machine, CNC Milling Machine

INTRODUCTION

Numerical control is the latest machine tools control system, which has been developed out of the need for higher productivity, lower cost and more precise manufacturing, can be considered as the most sophisticated form of automation for controlling machine tools, equipments and processes. In NC system, operation instructions are inputted to the machine as numbers which are suitably coded for storing on tapes. These instructions are then automatically carried out in the machine tool in predetermined sequence with pre set or self adjusted speed; feed etc., without human intervention. In the original NC systems the physical components are hard wired i.e. the circuitry and components can perform their respective functions only and are not flexible to adopt changes. In CNC system the physical components are software units. In software units the loaded program in computer makes the control unit operate to suite the need of machinist.

CNC Lathe:-

The Coordinate SystemAll CNC machines move tools to specific locations described by coordinate systems. With lathes the coordinate system can be simply described as two number lines that intersect.The illustration below shows two number lines that intersect at a location described as reference zero or Absolute Zero.

With lathes the vertical number line is called the X-axis. The horizontal number line is called the Z-axis. The intersection of the two lines is Absolute Zero.

When programming lathes X0 is always the centerline of the part you are working on. It is the X position on the Z axis that the part rotates around. Z0 normally is the front finished face of the part.

Machine Home

At start up machine tools must be returned to zero or taken to what is called a Home ReferencePosition. At home position the machine coordinates are X0, Z0. It would not be easy or convenient to write a program using machine coordinates. Instead programs are written with values that would correspond to dimensions found on prints. To do this a secondary floating zero point is established using offsets. This floating zero is referred to as the PART ZERO orPART ORIGIN

As shown above the centerline of the part becomes (X) zero. Normally the front face of the part is designated as Z (zero).

The diagram above shows the operator’s view of X and Z grid standing in front of the lathe. At the intersection of the X and Z axis is the Part Zero or Reference Point. Note there is four different quadrants with different positive and values for X and Z.

Give the X and Z coordinates for the part below. Note the X values are diameters on Lathes not radii.

Programming The definition of a part program for any CNC consists of movements of the tool and speed changes to the spindle RPM. It also contains auxiliary command functions such as tool changes, coolant on or off commands, or external M codes commands.Tool movements consist of rapid positioning commands, straight line movement of the tool at acontrolled speed, and movement along an arc.The Haas lathe has two (2) linear axes named X and Z. the X-axis moves the tool turret toward and away from the spindle center line, while the Z axis moves the tool turret along the spindle axis. The machine zero position is where the tool is at the right corner of the work cell farthest away from the spindle axis. Motion in the X-axis will move the table toward the spindle centerline for negative numbers and away from spindle center for positive numbers. Motion in the z-axis will move the tool toward the spindle chuck for negative numbers and away from the chuck for positive numbers.

A program is written as a set of instructions given in the order they are to be performed. Theinstructions, if given in English, might look like this:

LINE #1 = SELECT CUTTING TOOL.LINE #2 = TURN THE SPINDLE ON AND SELECT THE RPM.LINE #3 = TURN THE COOLANT ON.LINE #4 = RAPID TO THE STARTING POSITION OF THE PART.LINE #5 = CHOOSE THE PROPER FEED RATE AND MAKE THE CUT(S)LINE #6 = TURN OFF THE SPINDLE AND THE COOLANT.LINE #7 = RETURN TOOL TO HOLDING POSITION AND SELECT NEXT TOOL

Program Format

X and Z values are positioned in alphabetical order and grouped togetherG and M codes may be placed anywhere on a line but convention is that the G codes come first and the M codes come at the end of the block. This makes sense as the last thing to happen on a line is the M function.The G codes are completed first then the M code is performed on any given line.Command codes are first given by a letter then a number. Some codes like X,Z and F require decimal points. Others like S and G require an integer (a number with no fractional part). Example: G00 (G0) and M01 (M1). Preparatory Functions: “G” codes use the information contained on the line to make the machine tool do specific operations, such as: • Move the tool at rapid traverse. • Move the tool at feed rate along a straight line.• Move the tool along and arc at a feed rate in a clockwise direction.• Move the tool along an arc at a feed rate in a counterclockwise direction.• Move the tool through a series of repetitive operations controlled by “fixed cycles” such as, spot drilling, boring, and tapping.Miscellaneous Functions: “M” codes cause an action to occur at the end of the block. Only one M- Code is allowed in each block. Sequence Numbers: Sequence numbers are codes N1 through N9999 and are only used to locate a certain block or line within a CNC program. A program may be input without sequence numbers.Alphabetical Address Codes The following is a list of the Address Codes used in programming the lathe:

CNC Milling:-

The Cartesian Coordinate System

The first diagram we are concerned with is called a NUMBER LINE. This number line has a zero reference point location that is called an ABSOLUTE ZERO and may be placed at any point along the number line.Our concern is the distance and the direction from zero and is labeled as “Absolute Programming”

Remember that zero may be placed at any point along the line, and that once placed, one side of zero has negative increments and the other side has positive increments.Absolute and Incremental Positioning Absolute Positioning:With absolute positioning, we tell the machine where to move referenced to a common point, called X0 Y0 and Z0. Every time we need to move to a certain position, the ending point of that move is in direct relationship to this “common point”

Incremental Positioning:With incremental positioning, we are telling the machine where to go in relationship to where itcurrently is at. Basically like a set of directions given from where the machine stopped last.

Work Coordinate System What is a “Work Coordinate”? A work coordinate (also known as a part offset) is how we tell the machine where our part(s) are located with respect to the machine home position. Under the Work Offsets page in the control, we put the machine in jog and hand wheel the machine to the X & Y “Zero” location for our part, and use the “Part Offset Measure” key under the Reset key to set the corresponding work offset from our program (G54, G55, G56, etc…..)

Above: The relationship of machine home to “work home”, otherwise known as “work offset”Note: Because the location of machine home zero is in the upper right hand corner of the machine table our values for X and Y will always be negative. G54 – G59 Work Offsets These are the first G-Codes that were assigned to work coordinates. This how we tell the machine that we are working on part #1, part #2, etc. thru part #6. Originally no one thought we would need more than 6 part offsets, but thru time and the invention of new types of machines more needed.G154 P1 – G154 P99 Work Offsets These codes are the same as G54 to G59, they add more places as X & Y zero. We now can set up to 105 different “zeros” within the travels of our machine. On older Haas machines the extra work offsets were G110 to G129.Tool Length Offset The tool length offset is how we tell the machine where the top face of our part is located in the Z direction with respect to machine home. The tool length offset gives the distance from the end of the tool at home position to the top face of our part or other plane that the programmer has determined as the Z zero reference point. This information is stored in theTool Offset Memory.Each tool in the machine will have its own defined tool length stored in the tool offset register determined by the operator during set up. Other information about each tool is stored in the Tool Offset Register. For each tool, the coolant tube position and the diameter or radius are also stored. In the wear section, small alterations to the tool length and diameter or radius are stored. If you cursor to the right in the tool register, additional information about the tool may be stored: the number of flutes, the actual diameter, the tool type, and tool category with respect to size and weight. In the illustration below the spindle is sitting at the Z home position and shows the distance the spindle must go to reach +.100 above the face of the part. G43 code with an H-number tells the machine which tool length offset to use.

Advantages over ordinary machines:-1. CNC machines can be used continuously 24 hours a day, 365 days a year and only need to be switched off for occasional maintenance. 2. CNC machines are programmed with a design which can then be manufactured hundreds or even thousands of times. Each manufactured product will be exactly the same.3. Less skilled/trained people can operate CNCs unlike manual lathes / milling machines etc.. which need skilled engineers.4. CNC machines can be updated by improving the software used to drive the machines5. Training in the use of CNCs is available through the use of ‘virtual software’. This is software that allows the operator to practice using the CNC machine on the screen of a computer. The software is similar to a computer game.6. CNC machines can be programmed by advanced design software such as Pro/DESKTOP®, enabling the manufacture of products that cannot be made by manual machines, even those used by skilled designers / engineers.7. Modern design software allows the designer to simulate the manufacture of his/her idea. There is no need to make a prototype or a model. This saves time and money.8. One person can supervise many CNC machines as once they are programmed they can usually be left to work by themselves. Sometimes only the cutting tools need replacing occasionally.9. A skilled engineer can make the same component many times. However, if each component is carefully studied, each one will vary slightly. A CNC machine will manufacture each component as an exact match

Experiment-2

AIM:- Study of Robots. Applicability for various operations

APPARATUS:- Robot with six degree of freedom

THEORY:- A robot is an automatic mechanical device often resembling a human or animal. In 1928, one of the first humanoid robots was exhibited at the annual exhibition of the Model Engineers Society in London. Invented by W. H. Richards, the robot Eric's frame consisted of an aluminium body of armour with eleven electromagnets and one motor powered by a twelve-volt power source. The robot could move its hands and head and could be controlled through remote control or voice control . Modern robots are usually an electro-mechanical machine guided by a computer program or electronic circuitryAn robot consists of a number of rigid links connected by joints of different types,controlled and monitored by a computer. The branch of technology that deals with the design, construction, operation, and application of robots, as well as computer systems for their control, sensory feedback, and information processing is known as robotics. Robots have replaced humans in the assistance of performing those repetitive and dangerous tasks which humans prefer not to do, or are unable to do due to size limitations, or even those such as in outer space or at the bottom of the sea where humans could not survive the extreme environments.Robot ClassificationRobots may be classified, based on:• physical configuration• control systems Physical Configuration:• Cartesian configuration• Cylindrical configuration• Polar configuration• Joint-arm configuration(a) Cartesian Configuration:Robots with Cartesian configurations consist of links connected by linear joints (L). Gantry robots are Cartesian robots (LLL).(b) Cylindrical Configuration:Robots with cylindrical configuration have one rotary ( R) joint at the base and linear (L) joints succeeded to connect the links. The robot arm in this configuration can be designated as TLL. The space in which this robot operates is cylindrical in shape, hence the name cylindrical configuration.(c) Polar Configuration:Polar robots have a work space of spherical shape. Generally, the arm is connected to the base with a twisting (T) joint and rotary (R) and linear (L) joints follow. The designation of the arm for this configuration can be TRL or TRR. Robots with the designation TRL are also called spherical robots. Those with the designation TRR are also called articulated robots. An articulated robot more closely resembles the human arm.( d) Joint-arm Configuration:

a b

c d

The jointed-arm is a combination of cylindrical and articulated configurations. The arm of the robot is connected to the base with a twisting joint. The links in the arm are connected by rotary joints. Many commercially available robots have this configuration.

Classification Based on Control Systems:1. Point-to-point (PTP) control robot2. Continuous-path (CP) control robot3. Controlled-path robot Point to Point Control Robot (PTP):The PTP robot is capable of moving from one point to another point. The locations are recorded in the control memory. PTP robots do not control the path to get from one point to the next point. Common applications include: component insertion

spot welding hole drilling machine loading and unloading assembly operations Continuous-Path Control Robot (CP): The CP robot is capable of performing movements along the controlled path. With CP from one control, the robot can stop at any specified point along the controlled path. All the points along the path must be stored explicitly in the robot's control memory. Applications Straight-line motion is the simplest example for this type of robot. Some continuous-path controlled robots also have the capability to follow a smooth curve path that has been defined by the programmer. In such cases the programmer manually moves the robot arm through the desired path and the controller unit stores a large number of individual point locations along the path in memory (teach-in). Typical applications include: spray painting finishing gluing arc welding operations

Controlled-Path Robot:In controlled-path robots, the control equipment can generate paths of different geometry such as straight lines, circles, and interpolated curves with a high degree of accuracy. Good accuracy can be obtained at any point along the specified path. Only the start and finish points and the path definition function must be stored in the robot's control memory. It is important to mention that all controlled-path robots have a servo capability to correct their path.Robot Reach:Robot reach, also known as the work envelope or work volume, is the space of all points in the surrounding space that can be reached by the robot arm. Reach is one of the most important characteristics to be considered in selecting a suitable robot because the application space should not fall out of the selected robot's reach. For a Cartesian configuration the reach is a rectangular-type space. For a cylindrical configuration the reach is a hollow cylindrical space. For a polar configuration the reach is part of a hollow spherical shape.Robot reach for a jointed-arm configuration does not have a specific shape.9.9 Robot SelectionIn a survey published in 1986, it is stated that there are 676 robot models available in the market. Once the application is selected, which is the prime objective, a suitable robot should be chosen from the many commercial robots available in the market. The characteristics of robots generally considered in a selection process include: Size of class Degrees of freedom Velocity Drive type Control mode Repeatability Lift capacity Right-left traverse Up-down traverse In-out traverse Yaw Pitch Roll Weight of the robot 1. Size of class: The size of the robot is given by the maximum dimension (x) of the robotwork envelope. Micro (x < 1 m) Small (1 m < x < 2 m) Medium (2 < x < 5 m) Large (x > 5 m) 2. Degrees of freedom. The cost of the robot increases with the number of degrees of freedom. Six degrees of freedom is suitable for most works.3. Velocity: Velocity consideration is effected by the robot’s arm structure. Rectangular Cylindrical

Spherical Articulated 4. Drive type: Hydraulic Electric Pneumatic5. Control mode: Point-to-point control(PTP) Continuous path control(CP) Controlled path control 6. Lift capacity: 0-5 kg 5-20 kg 20-40 kg and so forth 9.10 Robot Applications Loading/unloading parts to/from the machines The robot unloading parts from die-casting machines The robot loading a raw hot billet into a die, holding it during forging and unloading it from the forging die The robot loading sheet blanks into automatic presses The robot unloading molded parts formed in injection molding machines The robot loading raw blanks into NC machine tools and unloading the finished parts from the machines Single machine robotic cell application The incoming conveyor delivers the parts to the fixed position The robot picks up a part from the conveyor and moves to the machine The robot loads the part onto the machine The part is processed on the machine The robot unloads the part from the machine The robot puts the part on the outgoing conveyor The robot moves from the output conveyor to the input conveyor Multi-machine robotic cell application: Two or three CNC machines are served by a robot. The cell layout is normally circular. Welding Spot welding: Widest use is in the automotive industry Arc welding: Ship building, aerospace, construction industries are among the many areas of application. Spray painting: Provides a consistency in paint quality. Widely used in automobile industry. Assembly: Electronic component assemblies and machine assemblies are two areas of application. Inspection

Experiment-3

AIM:- Study of various types of cutting tools for turning & milling (HSS, brazed carbide, carbide indexable inserts and solid carbide tools) viz. tools for turning & boring; milling cutters of plano, bull and ball-nose type and their use.

Theory:- Cutting tools are available in three basic material types: high-speed steel, tungsten carbide, and ceramic. High-speed steel is generally used on aluminum and other nonferrous alloys, while tungsten carbide is used on high-silicon aluminums, steels, stainless steels, and exotic metals. Ceramic inserts are used on hard steels and exotic metals. Inserted carbide tooling is becoming the preferred tooling for many CNC applications. For the full utilization of CNC machines it is essential to pay due attention to the selection and usage of tooling, namely tool holders, cutting tools and work holding devices. The tools for CNC machines must be quickly changeable to reduce non-cutting time, preset and reset outside the machine, high degree of interchangeability, increased reliability and high rigidity. The cutting tools can be classified on the basis of setting up of tool, tool construction and cutting tool material : On the Basis of Setting up of Cutting Tool (a) Preset tools. (b) Qualified tools. (c) Semi qualified tools. On the Basis of Cutting Tool Construction (a) Solid tools. (b) Brazed tools. (c) Inserted bit tools. On the Basis of Cutting Tool Material (a) High speed steel (HSS). (b) High carbon tool steel (HCS). (c) Cast alloy. (d) Cemented carbide. (e) Ceramics. (f) Boraon Nitride. (g) Diamond. Preset Tools The setting of tools in advance at a place away from the machine tool or offline, in special holders is known as preset tools. A presetting device is used to preset axial and radial positions of the tool tip on the tool holder. Once this is done, the tool holder is ready to be mounted on the machine and produce a known dimension. Presetting devices to various levels of sophistication are available like optical projector. Tool length and tool diameter compensation facilities available in the present day CNC machines have brought down the importance of presetting. Since the generation of actual geometry is taken care of by the CNC part program, which is

essentially the coordinates through which the cutting tool tip moves, it is important to know the actual dimensions of the tool when it is placed in the spindle. The relationship of the tool with reference to the tool holding mechanism requires a special attention during CNC machining process. The actual point to be programmed in a CNC part program is the tip of the tool whereas the axes will be moving with respect to a known point in the spindle, e.g. the centre of the spindle in case of machining centres. It becomes therefore necessary to know precisely the deviation of the tool tip from the gauge point on the spindle.

Qualified Tools Tool which fits into a location on the machine, where its cutting edge is accurately positioned within close limits relative to a specified datum on the tool holder or slide, is known as qualified tool. The cutting tools satisfy the following requriements : (a) Tools need not be measured individually.(b) No presetting device is used.(c) The dimensions of the tool holder which are fixed and known.(d) Set up time is reduced.(e) Control dimensions of the tool are nominal and fixed.(f) Higher control on resharpening e.g. drills, reamers.(g) Cutter for better size control e.g. end mills, teamers.(h) Chip breaking facilities incorporated in tool.(i) Impoved designs.

Semi-qualified Tools The qualified tools which can be adjusted to the dimensions by using several adjustable buttons on the tool shank are known as semi qualified tools. These tools demand regular maintenance and calibration for accurate dimensioning.

Solid Tools Solid tools are usually made of High speed steel or High carbon steel. These tools are used on high speeds with sufficient quantity of cutting fluid to get good suface finish and longer tool life.

Brazed Tools A forged shank of high strength steel with belt of high speed steel, tungusten carbide stellite brazed to the shank on the cutting edge.

Inserted Bit Tools The tools with indexible inserts of harder and special grade carbide or ceramic materials. A wear resistant layer of Titanium nitride of Titanium carbide is coated on the insert it reduces the cost of tool. Inserts can be easily removed from the tool holder. So tool changing time and cost of machining are less. High Speed Steel The H.S.S. is carbon steel to which alloying elements like tungusten, chromium,vanadium, cobalt and molyblemum to be added to increase their hardness and wear resistance. High Carbon Tool Steel High carbon tool steel is suitable for low cutting speeds and low temperatures. The hardness of this tool is determined by the carbon contents. Cast AlloyThis is a non ferrous alloy and gives high machining performance than that of H.S.Steel. Its hardness and toughness are high at higher temperatures. Cemented Carbides It contains 5% carbon, 13% cobalt and 81%tungsten. This tool is widely used in modern costly machines as tip tools. The tool setting time is reduced. Ceramics It can be used for higher cutting speed, superior surface finish and greate machining flexibility. The Aluminium oxides, boron carbides, silicon carbide, titanium borides and titanium carbides are known as ceramics. Boraon Nitride (a) High wear resistance.(b) Used for machining hardened steel and high temperature alloys. Diamond (a) Low friction and high wear resistance.(b) Good cutting edge.(c) Single crystal diamond is used to machine copper to a high surface finish.

Experiment-4

AIM:- Entering M-codes for spindle start/stop, coolant start/stop etc

Theory:- A Part Program is a list of coded instructions which describes how the designed component, or part, will be manufactured. These coded instructions are called data – a series of letters and numbers. The part program includes all the geometrical and technological data to perform the required machine functions and movements to manufacture the part. The part program can be further broken down into separate lines of data, each line describing a particular set of machining operations. These lines, which run in sequence, are called blocks. A block of data contains words, sometimes called codes. Each word refers to a specific cutting/movement command or machine function.The programming language recognized by the CNC, the machine controller,is an I.S.O. code, which includes the G and M code groups.Each program word is composed from a letter,called the address, along with a number.BLOCK CONFIGURATION. The sequence in which address codes appear in each block should remain consistent throughout the program. It is recommended that the order of these address codes follows the example shown below :

SPINDLE SPEED FUNCTION:-The rotational speed of the tool, with respect to the workpiece being cut, is called the spindle (or cutting) speed.The spindle speed is defined using the S address letter,followed by a numerical value, signifying the spindle RPM (revolutions per minute). The spindle speed value specified must fall between the machine tool RPM range for the command to be effective.

MØ3 - Spindle Forward (Clockwise) The clockwise direction of the spindle is determined by viewing from the back of the machine headstock,along the Z axis towards the tailstock.The spindle start command is activated at the beginning of the block in which it is programmed, ie, before any axis movement occurs.MØ4 - Spindle Reverse (Counter Clockwise):- An MØ4 code acts in the same way as an MØ3 code,only the spindle rotates in the opposite direction.MØ5* - Spindle Stop.The MØ5 code, to stop the spindle rotating, is activated at the end of the block in which it is programmed, ie , after any axis movement.MØ8 - Coolant On. This code switches the coolant pump on.MØ9* - Coolant Off. This code switches the coolant pump off.M13 - Spindle Forward and Coolant On.This code combines the functions of MØ3 and MØ8together. The MØ5 code will stop both the spindle and coolant.

M14 - Spindle Reverse and Coolant On. This code performs the same function as M13 but thespindle rotates in the opposite direction.M19 - Spindle Orientation.This code will orientate the machine spindle - see your machine specification.

Experiment -5

AIM:- Entering G-codes for straight and taper-turning operations.

Theory:-

Code Explanation N5 Clamping workpieceN10 Changing No.1 tool and executing its offsetN15 Rapidly positioning to A pointN20 Starting the spindle with 600 r/minN25 Cooling ONN30 Approaching B point with 600mm/minN40 Cutting from B point to C pointN50 Cutting from C point to D pointN60 Rapidly retracting to A pointN70 Canceling the tool offsetN80 Stopping the spindleN90 Cooling OFFN100 Releasing workpieceN110 End of program, spindle stopping and Cooling OFF

Experiment -5

AIM:- Entering codes for cutting along concave and convex arcs; Radius compensation

Theory:- The radius function is used to cut a convex or concave radius into a work piece by progressing through the cut in a series of small steps.  See the description of the radius function in the define menu section below for more detail on the parameters that define the radius.The reference point for the radius is taken from the incremental zeros for the two axes in the plane of the radius, either X and Z or Y and Z.  The reference point is defined as the center point of the radius for a concave radius or the point on the radius directly above the center point for a convex radius.  You must define the incremental zeros that define the reference point before starting the function.  The figure below shows the location of the reference points for both convex and concave radii.

Before starting the function, select the tool that you want to use for the cut.  The tool must be a ball nose cutter and the diameter and Z offset must be correctly defined for the tool.  If you initiate the radius function without a tool selected, it will display a message and cancel the function. The cutter radius compensation capabilities of the Interpreter enable the programmer to specify that a cutter should travel to the right or left of an open or closed contour in the XY-plane composed of arcs of circles and straight line segments

Data for Cutter Radius CompensationThe Interpreter world model keeps three data items for cutter radius compensation: the setting itself (right, left, or off), program_x, and program_y. The last two represent the X and Y positions which are given in the NC code while compensation is on. When compensation is off, these both are set to a very small number (10-20) whose symbolic value is "unknown". The Interpreter world model uses the data items current_x and current_y to represent the position of the center of the tool tip (in the currently active coordinate system) at all times.Programming:-Turning Cutter Radius Compensation OnTo start cutter radius compensation keeping the tool to the left of the contour, program G41 D…. The D word is optional (see "Use of D Number", just below).  To start cutter radius compensation keeping the tool to the right of the contour, program G42 D… .  In Figure A-1, for example, if G41 were programmed, the tool would move clockwise around the triangle, so that the tool is always to the left of the triangle when facing in the direction of travel. If G42 were programmed, the tool would stay right of the triangle and move counter clockwise around the triangle.Turning Cutter Radius Compensation OffTo stop cutter radius compensation, program G40. It is OK to turn compensation off when it is already off. Sequencing If G40, G41, or G42 is programmed on the same line as tool motion, cutter compensation will be turned on or off before the motion is made. To make the motion come first, the motion must be programmed on a separate, previous line of code. Use of D NumberProgramming a D word with G41 or G42, is optional.If a D number is programmed, it must be a non-negative integer. It represents the slot number of the tool whose radius (half the diameter given in the tool table) will be used, or it may be zero (which is not a slot number). If it is zero, the value of the radius will also be zero. Any slot in the tool table may be selected. The D number does not have to be the same as the slot number of the tool in the spindle, although it is rarely useful for it not to be.If a D number is not programmed, the slot number of the tool in the spindle will be used as the D number. Material Edge ContourWhen the contour is the edge of the material, the outline of the edge is described in the NC program.For a material edge contour, the value for the diameter in the tool table is the actual value of the diameter of the tool. The value in the table must be positive. The NC code for a material edge contour is the same regardless of the (actual or intended) diameter of the tool. Programming Entry MovesIn general, two pre-entry moves and one entry move are needed to begin compensation correctly. However, if there is a convex corner on the contour, a simpler method is available using zero or one pre-entry move and one entry move. The general method,which will work in all situations, is described first. We assume here that the programmer knows what the contour is already and has the job of adding entry moves.

General MethodThe general method includes programming two pre-entry moves and one entry move. See Figure A-2. The shaded area is the remaining material. It has no corners, so the simple method cannot be used. The dotted line is the programmed path. The solid line is the actual path of the tool tip. Both paths go clockwise around the remaining material. A cutter one unit in diameter is shown part way around the path. The black dots mark points at the beginning or end of programmed or actual moves. The figure shows the second pre-entry move but not the first, since the beginning point of the first pre-entry move could be anywhere. Figure A 2, Cutting radius compensation entry moves (for material edge contour)

First, pick a point A on the contour where it is convenient to attach an entry arc. Specify an arc outside the contour which begins at a point B and ends at A tangent to the contour (and going in the same direction as it is planned to go around the contour). The radius of the arc should be larger than half the diameter given in the tool table. Then extend a line tangent to the arc from B to some point C, located so that the line BC is more than one tool radius long. After the construction is finished, the code is written in the reverse order from the construction. The NC code is shown in Table A-1; the first three lines are the entry moves just described.

N0010 G1 X1 Y5 (make first pre-entry move to C)

N0020 G41 G1 Y4 (turn compensation on and make second pre-entry move to point B)

N0030 G3 X2 Y3 I1 (make entry move to point A)

N0040 G2 X3 Y2 J-1 (cut along arc at top)

N0050 G1 Y-1 (cut along right side)

N0060 G2 X2 Y-2 I-1 (cut along arc at bottom right)

N0070 G1 X-2 (cut along bottom side)

N0080 G2 X-2.6 Y-0.2 J1 (cut along arc at bottom left)

N0090 G1 X1.4 Y2.8 (cut along third side)

N0100 G2 X2 Y3 I0.6 J-0.8 (cut along arc at top of tool path)

N0110 G40 (turn compensation off)Cutter radius compensation is turned on after the first pre-entry move and before the second pre-entry move (including G41 on the same line as the second pre-entry move turns compensation on before the move is made). In the code above, line N0010 is the first pre-entry move, line N0020 turns compensation on and makes the second pre-entry move, and line N0030 makes the entry move.

Experiment-7

Entering specifications for various types of tools (viz. end-mill, ball-mill or bull-nose tools)

for programming.

 

The following is a summary of G codes.

Code: Group: Function: G00 01* Rapid Motion (ST20 945 in/min, ST30SS 1200 in/min in Z) G01 01 Linear Interpolation MotionG02 01 CW Interpolation MotionG03 01 CCW Interpolation MotionG04 00 Dwell (non-modal)G09 00 Exact Stop (non-modal)G10 00 Programmable Offset Setting (non-modal)G17 02 XY Plane Selection (used with live tooling)G18 02* ZX Plane Selection (Plane used on lathes) G19 02 YZ Plane Selection (used with live tooling)G20 06 Inch Programming Selection (setting #9)G21 06 Metric Programming SelectionG28 00 Machine Home in Rapid TraverseG29 00 Set Return to Reference PointG31 00 Skip FunctionG40 07* Tool Nose Compensation CancelG41 07 Tool Nose Compensation LeftG42 07 Tool Nose Compensation RightG50 11 Spindle Speed Clamp, Global CoordinateG51 11 Cancel G50 Offset (Yasnac) G52 00 Child Coordinate System, M30, Reset Cancels G53 00 Non-Modal Machine Coordinate Selection

G54 12* Select Work Coordinate System 1G55 12 Select Work Coordinate System 2G56 12 Select Work Coordinate System 3G57 12 Select Work Coordinate System 4G58 12 Select Work Coordinate System 5G59 12 Select Work Coordinate System 6G61 13 Exact Stop ModalG64 13* G61 Cancel

G65 00 Macro Subroutine CallG70 00 Finishing CycleG71 00 O.D./I.D. Stock Removal CycleG72 00 End Face Stock Removal CycleG73 00 Irregular Path Stock Removal Cycle G74 00 End Face Grooving Cycle, Peck Drilling G75 00 O.D./I.D. Grooving cycle, Peck DrillingG76 00 Thread Cutting Cycle, Multiple PassG80 09* Canned Cycle CancelG81 09 Drill Canned CycleG82 09 Spot Drill Canned CycleG83 09 Peck Drill Canned CycleG84 09 Tapping Canned CycleG85 09 Boring Canned CycleG86 09 Bore/Stop Canned CycleG87 09 Bore/Manual Retract Canned CycleG88 09 Bore/Dwell Canned CycleG89 09 Bore Canned CycleG90 01 O.D.I.D. Turning cycle, ModalG92 01 Thread Cutting Cycle, ModalG94 01 End Face Cutting cycle, ModalG96 12 Constant Surface Speed On G97 12* Constant Surface Speed Cancel G98 05 Feed per MinuteG99 05* Feed per Revolution G102 00 Programmable Output to RS-232G103 00 Block Look Ahead Limit (P0-P15) G110-G129 12 Extra Work Coordinate System 7 through 26 older MachinesG154P1 to 12 Extra Work offsets newer machinesG154P99 G184 09 Reverse Tap Canned Cycle G187 00 Accuracy Control for machining corners. G187 Ennnn will modify setting 85 – maximum corner rounding

Miscellaneous Functions (M Codes) M-codes are non-axes moving commands; also called machine functions. The format for M-codes is the letter “M” followed by two numbers, for example M01. Only one M-code is allowed on a single block of code. M-codes are the last thing to take effect on a line of code. M-codes are usually place at the end of a block of code. M00 Program Stop

Stops spindle, axes movement, turns off coolant On pressing CYCLE START button program will continue on from where it stopped M01 Optional program stop Works exactly the same as a M00 Is only active when optional stop key activates it on control panel

M02 End of program – cannot continue Most common way is using M30 M03 Start spindle forward (Clockwise) Must be accompanied by a spindle speed M04 Start spindle reverse (Counterclockwise) Must have a spindle speed (S value) M05 Spindle Stop M08 Coolant on Command M09 Coolant off Command M10 Clamp Spindle Chuck M11 Unclamp Spindle Chuck M21 Tailstock Forward M22 Tailstock Reverse M23 Thread Chamfer On during a G76 or G92 cycleM24 Thread Chamfer OffM30 Program end and rewind to beginning of programM41 Low GearM42 High GearM85 Automatic Door OpenM86 Automatic Door CloseM88 High Pressure Coolant OnM89 High Pressure Coolant Off M97 Local Sub-Program Call (P, L)M98 Sub Program Call (P, L)M99 Sub Program Return or Loop