Mini Project

CONTENTS 1 ABSTRACT 2 ABBREVIATION 3 entering TO NC AND CNC 4 4 HISTORY 7 5 CNC SYSTEM ELEMENTS 10 6 WORING ON CNC MACHINES 7 BASIC CONCEPTS OF PART PROGRAMMING 16 8 TYPES OF CNC MACHINES 18 9 PROPERTIES OF CNC MACHINES 20 10 long-winded AND TAPPING ON CNC 35 11 APPLICATIONS OF CNC MACHINES 49 12 ADVANTAGES AND DISADVANTAGES OF CNC 51 13 remainder 52 LIST OF FIGURES PAGE NO 1 Hydrotel Milling instrument 5 2 Chiron CNC auto 5 3 CNC Lathe car 6 CNC elements block diagram 10 5 Point to Point musical instrument caterpillar track 11 6 Contour spear Path 12 7 cease slight path ray kick the bucketments 18 8 Continuous path governlers 19 9 Schematic Illustrations of components(a)An open kink(b)A closed loop crack 19 10 CNC Lathe 21 11 CNC Grinders 21 12 CNC physical exerciseing 22 13 CNC tiresome utensil 22 14 Electrical Discharge Machines (EDM) 23 15 optical maser kinkting weapon legal documents 23 16 Flat bed CNC Lathe 25 7 rake bed CNC Lathe 25 18 CNC quill Tur rent 26 28 assorted beasts in Drilling forcecars 26 20 turncock Holders 27 21 CNC with Fanuc suss out 28 22 CNC compositor 29 23 upset Speed setter 31 24 CNC quail 32 25 Sensitive Drilling elevator car 37 26 Ra telephone dial oil production motorcar 38 27 Up-right Drilling auto 38 28 Drill materials 39 29 stopcock nomenclature 40 30 Tool holding devices 41 31 Various public presentations of oil production elevator cars 42 32 previse Boring 43 33 restitution sunk 43 34 Spot Facing 43 35 falls Taps 46 36 Holding Devices 48 7 Types of Clamps and C- Clamps 49 38 Products c tot every(prenominal)yd in Aerospace manufacture 49 39 5 Axis CNC Milling utensil 50 3. INTRODUCTION TO NC AND CNC quantitative retain(NC) refers to theautomationof gondola lancesthat ar puzzle outd by architectural planmed sees encoded on a storage medium, controlled manually via make it wheels or levers, or mechanismlikely change via cams alone. The first NC machines wer e make in the forties and 1950s. These early servomechanisms were rapidly increase with analog and huntal computers, creating the freshcomputer numeric control(CNC) machine diaphysiss that shoot revolutionized themachining exercisees.The course of study is iterated into the appropriate electrical signals for input to motors that evanesce the machine. A CNC machine is an numeral control machine with the added feature of an on bestride computer. The computer is referred to as the machine control social unit (MCU). In fresh CNC systems, component architectural plan is extremely automated expendcomputer-aided design( detent) andcomputer-aided manufacturing (CAM) architectural plans. The computer programs enkindle a computer file that extracts the summonss erectulate to operate a manicular(prenominal) machine, and wherefore soaked into the CNC machines for production.Since any component cleverness beg the use of a form of variant shits- employments, saw s, etc. , modern machines oft feature aggregate bastards into a single cell. The Evolution of NC It was in 1947 when numerical control was born. It began when John C. Parsons of the Parsons Corporation, Traverse City, Michigan, a reconstructr of helicopter rotor coil blades, could not make his templates immobile enough. So, he invented a agency of trades union computer equipment with a jig wear uponr. Mr. Parsons employ punched cards to operate his digit Ron system. 1949 was the year of an former(a) Urgent lease. The U. S.Air visible command agnise that transgresss for its planes and missiles were becoming to a greater extent complex. Also, as the designs were constantly being improved, changes in the drawing were frequently make. Thus, in their search for methods of faster production, an Air take up study contract was awarded to the Parsons Corporation. The servo mechanisms laboratory of the Massachusetts Institute of applied science (MIT) was the subcontractor. I n 1951, MIT took over the complete job, and in 1952, the proto oddball of todays NC machine, a modified Cincinnati Hydrotel Milling Machine, was successfully demonstrated.The numerical control was originated at MIT. build1 common fig2 CNC MACHINES CNC outdoor stages for Computer Numerically Controlled. CNC refers to how a machine operates, that is, its basic method of controlling try, e. g. , a CNC machine uses a stream of digital education (code) from a computer to bear motors and other positioning systems in order to guide a pergola or other beam just abouting over raw material. A CNC machine uses mathematics and a landmark systems to understand and unconscious service information ab by what to take to the woods, to where, and how fast.Most CNC machines ar able to move in three controlled focussings at once. These directions ar called axes and atomic number 18 wedded unprejudiced names such as X, Y and Z ( base on the Cartesian Co-ordinate dodging). The X a xis vertebra is al sorts the longest distance a machine or a part of a machine must(prenominal)(prenominal) travel. X whitethorn be the movement from front to back, Y the movement from left to right, and the Z is al al close to al flairs vertical movement ( unremarkably the arbors positioning movement up and guttle). Superior Machinery sells many eccentric persons of CNC Machines, from CNC Horizontals, CNC Verticals to CNC Lathes they fork up over 182 CNC Machines to choose from.A CNC machine must be able to hap with itself to operate. A computer numeric control unit sends position commands to motors. The motors must talk back to the control that, indeed, they fork out acted represently to move the machine a given distance. The ability of CNC machines to move in three (or to a greater extent) directions at once allows them to create almost any desired pattern or shape. All of this appendageing happens very fast, perfectly and liveently. 4. HISTORY form3 In 1775, John Wi lkinson- rotternon boring machine (lathe). In 1881, Eli Whitney- mill machine. In 1947, Mr.John Parsons began experimenting for utilize 3-axis curvature data to control the machine woodpecker motion for the production for aircraft components. In 1949, parsons- first NC machine. In 1951, MIT was involved in the project. In 1955, later on refinements NC became available in industry . Today, modern machineries be CNC milling machines and lathes. CNC technology was developed in the United States in the 1950? s for the US Air Force by admixture pee-peeing machine whoreson builders. It was a major advance in the ability of machines to faithfully retch complex part machining move more accurately without human treatment or variability.Numerical control (NC) refers to the automation of machine dents that argon operated by abstractly programmed commands encoded on a storage medium, as opposed to manually controlled via business dealwheels or levers, or mechanically automated via c ams alone. The first NC machines were reinforced in the 1940s and 1950s, based on existing beam of lights that were modified with motors that moved the controls to follow evinces supply into the system on punched tape. These early servomechanisms were rapidly augmented with analog and digital computers, creating the modern computer numerical control (CNC) machine son of a oddballchs that present revolutionized the machining processes.In modern CNC systems, end-to-end component design is highly automated employ computer-aided design (CAD) and computer-aided manufacturing (CAM) programs. The programs produce a computer file that is interpreted to extract the commands needed to operate a particular machine via a postprocessor, and then loaded into the CNC machines for production. Since any particular component capability require the use of a number of diametric legal documents- practises, saws, etc. , modern machines ofttimes combine mul taple joyrides into a single cell.In other cases, a number of contrasting machines argon utilize with an external controller and human or robotic manipulators that move the component from machine to machine. In any case, the complex series of steps needed to produce any part is highly automated and produces a part that closely matches the original CAD design. Proliferation of CNC The price of computer beats knock fling off drastically during the 1960s with the widespread introduction of multipurpose minicomputers. Eventually it became slight expensive to negociate the motor control and run forback with a computer program than it was with dedicated servo systems.Small computers were dedicated to a single mill, placing the entire process in a small box. PDP-8? s and Data General Nova computers were park in these roles. The introduction of the microprocessor in the mid-s raseties further reduced the cost of implementation, and today almost all CNC machines use or so form of microprocessor to hide all oper ations. The introduction of tear down-cost CNC machines radically changed the manufacturing industry. Curves atomic number 18 as elementary to curtail off as straight neckcloths, complex 3-D structures argon relatively easy to produce, and the number f machining steps that required human accomplishment have been dramatically reduced. With the increased automation of manufacturing processes with CNC machining, considerable improvements in consistency and eagre have been achieved with no strain on the operator. CNC automation reduced the absolute frequency of errors and submitd CNC operators with condemnation to cause additional tasks. CNC automation too allows for more trac sidestepness in the way parts ar held in the manufacturing process and the cartridge clip required to change the machine to produce dissimilar components.During the early 1970s the Western economies were mired in slow economic growth and come up employment costs, and NC machines started to becom e more attractive. The major U. S. vendors were slow to respond to the require for machines suitable for lower-cost NC systems, and into this void stepped the Germans. In 1979, sales of German machines surpassed the U. S. designs for the first time. This bout quickly repeated itself, and by 1980 Japan had taken a flatusing position, U. S. sales dropping all the time. Once sitting in the 1 position in terms of sales on a top-ten graph consisting entirely of U. S. ompanies in 1971, by 1987 Cincinnati Milacron was in 8th place on a chart heavily dominated by Japanese firms. galore(postnominal) researchers have commented that the U. S. focus on high-end applications left them in an uncompetitive arguing when the economic down address in the early 1970s led to greatly increased demand for cheap NC systems. Un uniform the U. S. companies, who had focuse on the highly profitable aerospace market, German and Japanese manufacturers targeted lower-profit segments from the start and we re able to enter the low-cost markets much more easily. As computing and net seduceing evolved, so did direct numerical control (DNC).Its long-term coexistence with less net urinateed variants of NC and CNC is explained by the fact that individual firms campaign to stick with whatever is profitable and their time and money for trying out alternatives is limited. This explains why machine dent models and tape storage media persist in grandfathered fashion even as the state of the art advances. 5. CNC SYSTEM ELEMENTS A typical CNC system consists of the following hexad elements. 1 severalise program 2 Program input device 3 Machine control unit 4 Drive system 5 Machine peter 6 Feedback system Fig4 6. WORKING OF CNC MACHINESCNC machines are Controlled by G and M codes. These are number values and co-ordinates. Each number or code is assigned to a particular operation. Typed in manually to CAD by machine operators. G&M codes are automatic rifleally generated by the computer sof tware package. The tool or material moves. Tools drive out operate in 1-5 axes. Larger machines have a machine control unit (MCU) which manages operations. Movement is controlled by a motor (actuators). Feedback is provided by sensors (transducers) unsympathetic loop. Tool magazines are utilise to change tools automatically. Tool Paths and Cutting questionsTool paths let out the route the excision tool takes. Motion tooshie be exposit as power point to point, or contouring. Speeds are the rate at which the tool operates e. g. rpm. Feeds are the rate at which the bang-up tool and work man move in relation to each other. Expressed in IPM (inches per minute) Feeds and fixitys are determined by knifelike abstruseness, material and quality of finish needed. e. g . harder materials need slower reachs and securenesss. Rouging cuts run into larger amounts of material than finishing cuts. fast traversing allows the tool or work forgather to move rapidly when no machining is taking place.Fig6 Point to Point Tool path Fig5Contour ToolPath 1. Point to Point tool paths cut following lines 2. Contour tool paths cut follow surfaces Linear Interpolation (Point to Point) Linear interpolation consist of a programmed point linked together by straight line Fig7 Circular Interpolation (Contour) Circular interpolation is the process of programming arcs and circles. Circular interpolation requires endpoints, a move over rate, a center, a radius, and a direction of movement. farce of Information When running, a part program is interpreted one command line at a time until all lines are completed.Fig8 N001 G01 X1. 2345 Y. 06789 MO3 N001Represents the sequence number of the operation G01 Represents bilinear operation (tool movement) X12345 Will move the tool or table 1. 2345 in. a positive direction along the X axis Y6789Will move the tool or table 0. 6789 in. along the Y axis M03Turns spindle on clock quick-scented Commands, which are in addition referred to as blocks, are do up of words which each begin with a letter utter and end with a numerical value. Each letter address relates to a specific machine function. G and M letter addresses O-Program number ( apply for program identification)N-Sequence number (Used for line identification) G-Preparatory function X-X axis name Y-Y axis engagement Z-Z axis designation R-Radius designation F-Feed rate designation S- spike heel speed designation H-Tool aloofness offset designation D-Tool radius offset designation T-Tool name M-Miscellaneous function G- CODES (Preparatory Functions) which cause some movement of the machine table or head. G00 Rapid Movement G01- Linear Interpolation (movement) G02- Circular Interpolation, CW G03- Circular Interpolation, CCW G17 -XY sheet,G18- XZ Plane,G19 -YZ Plane G20/G70 -Inch unitsG21/G71 -Metric Units G40- Cutter payment mountaincel G41 -Cutter recompense right G43- Tool length compensation (plus) G43- Tool length compensation (plus) G44- Tool length compensation (minus) G49-Tool length compensation give the sackcel G80-Cancel evokened cycles G81-Drilling cycle G82-Counter boring cycle G83-Deep hole boring cycle G90-Absolute positioning G91- Incremental positioning M-CODES (Miscellaneous) which turn ON or OFF different functions M00 -Program retrovert M01 -Optional program stop M02 -Program end M03- Spindle on clockwise M04 -Spindle on counterclockwise M05- Spindle stop M06- Tool change . BASIC CONCEPTS OF PART PROGRAMMING Part programming contains geometric data virtually the part and motion information to move the lancinate tool with respect to the worpiece. Basically, the machine receives instructions as a sequence of blocks containing commands to set machine parameters speed, bleed and other relevant information. A block is equivalent to a line of codes in a part program. N135 G01 X1. 0 Y1. 0 Z0. 125 T01 F5. 0 These bound N135-Block number G01-G codes X1. 0, Y1. 0, Z0. 125-Coordinates T01-Tool number F5. 0-Special fu nction Programming Methods Automatically Programmed Tools (APT)A text based system in which a programmer defines a series of lines, arcs, and points which define the overall part geometry locations. These features are then employ to generate a stamp location (CL) file. Computer Aided Machining (CAM) Systems-Computer Aided Design (CAD) Systems CAD/CAM systems allow for rapid development and modifying of designs and documentation. The 3D geometric model produced becomes a common element for engineering analysis (FEA), machining process planning (including CNC part programming, documentation (including engineering drawings), quality control, and so on.Drives of CNC machine tool hydraulic actuator high force machine tool Stepping motor small machine repayable to limited condition and torque DC motor fine speed regulation, high torque, most widely utilise. 8. PROPERTIES OF CNC MACHINES Based on Motion Type Motion control the heart of CNC Point-to-Point or Continuous path Based on Control Loops Open loop or Closed loop Based on Power Supply Electric or Hydraulic or Pneumatic Based on Positioning System Incremental or Absolute Point-to-Point Tool Movements Point-to-point control systems cause the tool to that point still.The tool is not in continuous contact with the part while it is moving. Excopiouss exerciseing, reaming, punching, boring and tapping. Fig9 Continuous-Path Tool Movements Continuous-path controllers cause the tool to maintain continuous contact with the part as the tool cuts a contour shape. These operations include milling along any lines at any cant over, milling Fig10 Arcs and lathe turning. Loop Systems for Controlling Tool Movement Schematic illustration of the components of (a) an open-loop and (b) a closed-loop control system for a CNC machine. 9. TYPES OF CNC MACHINES * Lathe Machine * Milling Machine Drilling Machine -The bench act -The pillar commit * Boring Machine * Grinding Machine CNC mill around These machining centers use computer controls to cut different materials. They are able to translate programs consisting of specific number and letters to move the spindle to various locations and abstrusitys. Used to make 3D prototypes, moulds, cutting dies, printing plates and sights. CNC Lathes They cut metal that is often turning at fast speeds. CNC lathes are able to make fast ,precision cuts using Indexable tools and applications with complicated programs. Normally, they cannot be cut on manual lathes.They often include 12 tool holder sand coolant pumps to cut down on tool wear. Fig11 CNC Grinders Grinding metal process uses a coated wheel that easily removes metal to create a part. Through the years, grinding was do on a manual machine, still with the advent of CNC technology, the grinding process has advanced . Fig12 CNC DRILLING Drilling is commonly used for mass production. The physical exertioning machine ( rehearseing press) is used to create or pad holes. The bench usage For drill h oles by means of raw materials such as wood, plastic and metal The pillar drill A larger version that stands upright on the al-Qaeda.As the bench drill, it can be used to drill larger pieces of materials and produce bigger holes. Fig13 CNC Boring Process of enlarging an existing hole or inborn cylindirical surface. This can be fulfill on a lathe or a machine tool specifically designed for the process, such as a crosswise boring machine. Fig14 Electrical Discharge Machines (EDM) cable EDM machines utilize a very thin conducting cable (. 0008 to . 012in. ) as an electrode. The wire is stretched betwixt diamond guides and carbide that conduct current to the wire and cuts the part bid a band saw.Material is removed by the erosion caused by a spark that moves horizontally with the wire. Fig15 Laser Cutting Machines The machine utilizes an intense beam of focused laser light to cut the part. Material under the beam experiences a rapid rise in temperature and is vaporized. Laser cuts with a minimum of distortion, no mechanical cutting forces. Specific tools to perform different surgical procedures Fig16Fig17 CNC lathe machine tool gun enclosure is part of the CNC machine where all tooling is mounted. CNC lathe tool gun enclosure has an integral magnetic disc like part (Tool gun enclosure disk) on which all the tools are mounted.CNC lathe tool turret is mounted on the x-axis carriage. Fig18 Slant cognize CNC Lathe / Flat Bed CNC Lathe On some CNC lathe machines x-axis carriage with the tool turret is located behind the spindle (such cnc lathe machines are calledslant bed cnc lathe machines) and on other cnc lathe it is located at the front (as normal lathe machines) such cnc lathe machines are calledflat bed cnc lathe machine. The infra is a Slant Bed CNC Lathe Machine. Fig19 Fig20 CNC Lathe Tool Turret Tool force Tool capacity for cnc lathe machines varies machine to machine.Small CNC lathe machines normally comes with a tool turret capacity of 4 o r 8 tools stations. Bigger andheavy CNC lathe machines tool turrets are big and heavy and accordingly depart hold more tools such as 12 or more. Fig21 Tool Holder Tool holder is the actual part which fastens the tool to the cnc lathe tool turret Disk. Tool holder size alike depends upon the cnc lathe tool turret size, heavy CNC late machine tool turret comes with with big bore for tool holders such as 50 mm diameter. For the small tool turret this might be 40 mm diameter or, less to suit the tool to hold.Fig22 CNC Lathe Tool Turret Rotation CNC lathe tool turret rotates with the cnc program commands. Normally a letter T is used to call a tool in the working position. The tool gyration is dependent on cnc lathe machine. rough cnc lathe tool turret rotate in one direction (CW or CCW ). Some cnc lathe tool turret rotates twain directions, such tool turret direction is optimized for the nearest tool station. Some cnc lathe give full control over tool call up, you can call by optimi zed direction or you can call tool by rotating tool turret by CW direction or CCW.Tool scratch in CNC Lathe with Fanuc Control Fig23 There are shape of cnc machines in the market, and almost every cnc machine in acnc kit and boodlehophas different kind of cnc machine controls if controls are not different they might have different versions of the same cnc machine control. As the operating of different cnc machines controls is very much different from one another the same wayTool Offsettingis very much different. Here I depart talk intimately the cnc tool invoicement on Fanuc. Tool Offset Setting on Fanuc TCSome cnc machines has some kind of built-in mechanism of tool-offsetting, this built-in mechanisn of tool-offsetting makes adding new tools are changing existing tools a breeze, because you beneficial tie-up the tool in the tool-post on thecnc machine tool-turretand just perform the summons the cnc machine manufacture has given in the cnc machine operating and setting m anual. TheFanuccontrols such as Fanuc TC has this capability, Just tie up tool in the tool turret and perform a simple procedure and everything is done. The tool offsetting procedure might be different from version to version, unless on Fanuc TC this procedure is simple as under.For tool offsetting of a new tool just tie up the tool in the tool post and inMDI (Manual Data Input) elancall up the tool in the working position by entering the command T1, the T is for tool call up and 1 is tool number if you have your tool on another position you might change that with that tool number. at once change the cnc machine to Jog Mode and touch the tool cutting point to the finished component (already gripped in cnc machine jaws) face and process the Tool-Geometry page and enter under the tool number the command MZ0 this command impart clear any previous values and will measure the current tools tool-offset in Z-axis. immediately touch the tool to aknown-diameteron the component and again in the tool-geometry page enter the command MX50 you can enter the measured diameter value instead of 50. This way now we have calculated the tool-measurement on the Fanuc TC cnc machine control. CNC juiceless concord Invaluable Tool for CNC Setter Fig24 It shows the power and the flexibility the cnc machine manufacturers and cnc control manufacturers give acnc machine setterby integrating the Dry go by dint ofon cnc machines. On some cnc machines the Dry Run is added as aCNC Machine Modelike Fanuc.On Fanuc cnc control you just select the Dry Run mode and cnc machine is now in Dry Run Mode. Introduction of Dry Run for CNC Machines Setting a new component on a cnc machine is not an easy job. You have to go by means of many chief(prenominal) tasks like cnc machine zero offsetting (cnc machine shift value setting),tool offsetting of toolsused on cnc machine etc. Now if you have completed these all tasks, now comes the time to run the cnc program for the first time, A in truth cr ucial and time consuming cnc task. A small negligence might be cause of an accident on cnc machine (tool breakage etc. . To make the first run easy and safe the cnc machine manufacturers and cnc control manufacturers provide us a way by which we can easily control the tools cater withfeed overturn. So now the cnc setter is a human activity easy because he can now run all the tools with aSafe Feed. Now cnc setter easily can lower the tool feed when he feels the tool is entering a situation danger zone, and easily can increase the tool feed (to a rapid feed) when the tool is away from the component (so the time not go bollix upd with lower feed when tool is away from component).In Dry Run all the cnc blocks whether those are starting with G00 or G01 and otherG-codelike G02/G03 run with the same feed, which is controlled by means of Feed Override. On Fanuc the feed rule is controlled throughHandwheelafter feed change by reversal exceptton press, and there also exists a Rapid F eed Button which if pressed during Dry Run Mode the cnc machine program block will run with Rapid Feed. hotshot point must be cleared for Fanuc control is that feed override also works inAuto Mode and Single Block Modebut in such modes the feed override only controls G01/G02/G03 like G-code.But feed override will not control the G00 (Rapid Traverse). But in Dry Run Mode all the cnc program will run with the feed which is controlled through Feed Override. An introduction to cnc machine speed override and feed override controls and safety instructions which must be adhere to while working with cnc machine feed and speed override. CNC Machine Speed Override / Feed Override Introduction Normally you program the speed and feed this way, N10 G97 S light speed0 G95 F0. 3 Fig25Now for one reason or other you want to increase or decrease the speed or feed of the cnc machinefor some time, you definitely have a way to just alter thecnc machine program, but there is one more suitable solution the Feed Override and Speed Override Controls. The feed override and speed override arethe most suitable and ready to hand(p) way to control thecnc machine feed and speed through cnc control panel. You control the speed and feed in percentage. When the feed overrideis 100% the actually feedwhich is programmed will be active.But if the feed overrideis 50% then the feedwill decrease by that ratio, now the machine tools will run with 50% of feed. So if youhave programmed 0. 5 mm/rev feed then with 100% the 0. 5 will be active, but for 50%feed override the actually tool feed will be 0. 25 mm/rev. The same rule applies for speed override, for 100% the actual programmed speed will be active and spindle will revolvewith the actual programmed speed. Butat 50% speedoverride the spindle speed will drop by 50%. Feed Override Speed Override Minimum Maximum determine Normally you can control speed override and feed override from 0% to one hundred twenty%.At 0% speed override the spindle will s top rotating, and at 0% feed override the tool will stop working ( the tool will be stationary ). No doubt120% feedoverride and speed override is justsafe. But some cnc machines give even more flexibility Ihave worked on a cnc machine which has its feed override 0% to 200%. Normal cnc machine has just 0% to 120% feedoverride and speed override. Speed Override and Feed Override sentry duty Precautions Whenever handling the speed override and feed override forever and a day esteem about safety, safety of yourself, tool, machine, component and your surroundings.Never try to use the speed override and feed override if you dont need it. Because when cnc programs are made the speed and feed is properly set for the machined component. The increase in feed or speed might break insert or even tool. CNC Backlash CNC Troubleshooting, In this category we will see the cnc machine from a different view (cnc machine maintenance), your feedback will really matter, and I hope you will share you knowledge and experience. I will talk about theCNCBacklashwhich is found in cnc machine axis. * what is cnc fall out, * cnc backlash causes, * when to worry about cnc backlash, how to measure backlash, * How to resolve and compensate cnc backlash through hardware and cnc control software. Fig26 *What is CNC Backlash? CNC Backlash is any kind of play which is found in cnc machine axis. or you might say, CNC Backlashis non-movement of the cnc axis which occurs on axis reversal. *Causes of CNC Backlash? This play (backlash) might be due to * Clearance which is kept in mechanical parts to reduce friction. * As mechanical parts get loose with time. * As with time mechanical parts keep moving and rubbing each other and after long time they lose their actual shape and size. CNC Backlash Is already there A cnc machine axis move due to their hire ScrewandLead Screw Nut. There is always kept a very minor backlash in the lead whop and lead butt nut to reduce damage and wear. *CNC Backlash When to Worry It is unafraid if your cnc machine axis backlash is near 0. 0001? but not always possible, so 0. 0003? to 0. 0004? is acceptable. But if the amount of play in the lead bonk and nut crosses this limit then there is the time to worry, and call up you mechanical maintenance guys. CNC Backlash How to Measure?CNC machine backlash can be measure with aDial Indicatorattached to an adjustable Stand. Put the stand on the cnc bed and direct the needle (plunger) of the dial indication towards the axis which you want to measure. 1. Set the dial needle to 0. 0mm (zero). 2. Now move the axis in one direction 0. 5mm. Dial indicator should show 0. 5mm travel. 3. Now reverse the same axis 0. 5mm. If your dial indicator now goes back to 0. 0mm, then everything is okay. But other than, if on reversal the dial lags behind, then the amount the dial lags behind is the backlash.CNC Backlash How to Resolve? ( Backlash Compensation ) Now you have two choices the hardware way and software w ay to resolve cnc backlash. You first better choose the hardware way, because normally backlash is due to lead bum or lead screw nut wear, so better resolve the issue by tighten them a bit if they are loose than required, there are lot of other hardware ways to cope with backlash. CNC controls also give us the ability to control (compensate) cnc backlash through their parameters. CNC Backlash Compensation through CNC Control Parameters How Much Successful?The better advice is that you resolve the issue by changing the lead screw (if possible) or lead screw nut, or just tightening them if they are loose might work, but otherwise CNC control parameters can be changed to compensate backlash, the cnc lathe machine I work on with fanuc control has the 0. 012mm set in its parameters as the backlash compensation for x-axis and z-axis. So such values can be changed to resolve the backlash issue. 10. DRILLING AND TAPPING ON CNC MACHINES Drilling is the operation of producing circular hole in the work-piece by using a rotating cutter called DRILL.The machine used for drill is called drilling machine. The drilling operation can also be accomplished in lathe, in which the drill is held in tailstock and the work is held by the scour. The most common drill used is the twist drill. Drilling Machine It is the simplest and accurate machine used in production shop. The work piece is held stationary ie. Clamped in position and the drill rotates to make a hole. Types 1) Based on construction Portable, Sensitive, radial-ply tire tire, up-right, Gang, Multi-spindle 2) Based on Feed Hand dictated ,Power determined Components of drilling machineSpindle The spindle holds the drill or cutting tools and revolves in a fixed position in a sleeve. weapon The sleeve or quill assembly does not revolve but may slide in its bearing in a direction parallel to its axis. When the sleeve carrying the spindle with a cutting tool is lowered, the cutting tool is fed into the work and when i ts moved upward, the cutting tool is withdrawn from the work. Feed pressure applied to the sleeve by hand or power causes the revolving drill to cut its way into the work a fr put to death of an mm per revolution. ColumnThe pillar is cylindrical in shape and built rugged and solid. The column supports the head and the sleeve or quill assembly. period The head of the drilling machine is composed of the sleeve, a spindle, an electric motor and feed mechanism. The head is bolted to the column. Worktable The worktable is supported on an lace mounted to the column. The worktable can be adjusted vertically to patch up different acmes of work or it can be swung only out of the way. It may be tilted up to 90 gradation in either direction, to allow long pieces to be end or angle cut. BaseThe base of the drilling machine supports the entire machine and when bolted to the floor, provides for vibration-free operation and best machining accuracy. The top of the base is similar to the wor ktable and may be equipped with t- slot for mounting work too larger for the table. Hand Feed The hand- feed drilling machines are the simplest and most common type of drilling machines in use today. These are light duty machine that are operated by the operator, using a feed handled, so that the operator is able to feel the action of the cutting tool as it cuts through the work piece. These drilling machines can be bench or floor mounted.Power feed The power feed drilling machine are unremarkably larger and heavier than the hand feed ones they are equipped with the ability to feed the cutting tool in to the work automatically, at preset depth of cut per revolution of the spindle these machines are used in maintenance for medium duty work or the work that uses large drills that require power feed larger work pieces are usually clamped now to the table or base using t bolts and clamps by a small work places are held in a vise. A depth stop mechanism is located on the head, near the spindle, to aid in drilling to a precise depth.Sensitive or Bench Drilling Machine * This type of drill machine is used for very light works. Fig. 1 illustrates the sketch of sensitive drilling machine. * The vertical column carries a swiveling table the height of which can be adjusted according to the work piece height. * The table can also be swung to any desired position. * At the top of the column there are two pulleys connected by a belt, one pulley is mounted on the motor diaphysis and other on the machine spindle. * Vertical movement to the spindle is given by the feed handle by the operator. * Operator senses the cutting action so sensitive drilling machine.Fig27 Up-Right Drilling Machine * These are medium heavy duty machines. * It specifically differs from sensitive drill in its weight, rigidity, application of power feed and wider range of spindle speed. Fig. 2 shows the line sketch of up-right drilling machine. * This machine usually has a gear compulsive mechanism fo r different spindle speed and an automatic or power feed device. * Table can move vertically and radially. * Drill holes up to 50mm Fig28 Radial Drilling Machine * It the largest and most several(a) used for drilling medium to large and heavy work pieces. Radial drilling machine belong to power feed type. * The column and radial drilling machine supports the radial arm, drill head and motor. Fig. 3 shows the line sketch of radial drilling machine. * The radial arm slides up and down on the column with the help of elevating screw provided on the side of the column, which is driven by a motor. * The drill head is mounted on the radial arm and moves on the guide ways provided the radial arm can also be swiveled around the column. * The drill head is equipped with a separate motor to drive the spindle, which carries the drill bit.A drill head may be moved on the arm manually or by power. * Feed can be either manual or automatic with reversal mechanism. Drill Materials The two most comm on types are 1. HSS drill- diminished cost 2. Carbide- tipped drills high production and in CNC machines Other types are Solid Carbide drill, TiN coated drills, carbide coated masonry drills, parabolic drills, split point drill. Fig. 4 shows various types of drills. Drill fixed to the spindle Fig30 Tool Nomenclature Fig. 31 Nomenclature of twist drill Tool holding devices Fig. 7 and Fig. 8 shows the different work holding and drill drift device.The different methods used for holding drill in a drill spindle are * By directly fitting in the spindle hole. * By using drill sleeve * By using drill socket * By using drill chuck Fig32 Drilling operations Operations that can be performed in a drilling machine are * Drilling * Reaming * Boring * Counter boring * Countersinking * Tapping Drilling It is an operation by which holes are produced in solid metal by means of revolving tool called Drill. Fig. 9 shows the various operations on drilling machine. Reaming Reaming is accurate way of s izing and finishing the exist hole.Multi tooth cutting tool. Accuracy of 0. 005mm can be achieved. Boring Boring is a process of enlarging an existing hole by a single point cutting tool. Boring operation is often preferred because we can correct hole size, or alignment and can produce smooth finish. Boring tool is held in the boring bar which has the shank. Accuracy of 0. 005mm can be achieved. Fig. 33 Various operations on drilling machine Counter Bore - This operation uses a pilot to guide the cutting action to apply the heads of bolts. Fig. 10 illustrates the counter boring, countersunk and spot facing processes. Countersink-Special go cone shaped enlargement at the end of the hole to accommodate the screws. Cone angles of 60, 82, 90, 100, 110, 120 Fig. 34 Counter boring, countersunk and spot facing Drillingmachines are tools that have a rotating, cutting component at one end that bores holes into different materials. There are several types ofdrillingmachines that may be use d for a wide variety of purposes, including woodworking, construction,masonry, metalworking, medicine, oildrilling, and many other fields. jet drills include the hand drill, push drill, pistol-grip drill, hammer drill, anddrill press.In addition to qualification holes, drills are often used to push screws into wood, metal, plastic, rock, or composites. The hand drill and push drill are both manually operateddrillingmachines that have been largely replaced by power drills. A hand drill works by turning a crank that rotates gears, which cause the chuck to turn. The chuck is the component of thedrillingmachinethat holds the bit, or the end cutting piece. The push drill is a skinny tool resembling a screwdriver with a handle that can be pushed down on a threaded shaft, or a pole with helical ridging.As the handle is pushed down along threading, the shaft, chuck, and bit spins downward, much like pumping a toy metal top. Pistol-grip drills are the most commonly useddrillingmachines. Th ese are corded electric drills that are typically shaped roughly like a pistol, with a knowledgeableness switch that starts a motor inside the drill. The motor causes the chuck and bit to spin in continuous revolutions. These drillingmachines may be used to make holes for bolts or other purposes, to push screws into wood, plastic, or other materials, and to bore countersinks.Acountersinkis a screw-shaped hole that is made before the screw is drill in, preventing splintering or pulling of the plastic or wood around the head of the screw. A pistol-grip drill is also available in a battery-powered, cordless version, though they are usually more expensive. There are many different types of this drill and several indications for use. It is also possible to adapt the drill with an attachment, such as sanding or sawing components. A hammer drill, also called a rotary hammer, is similar to a pistol-grip drill, but also applies a punching motion to complement the rotational action of the bit.This hammering, forward force makes it useful for tougher materials, such as concrete or stone, that standard electric drills cannot cut through. For softer materials, however, the hammer drill may apply excessive force and a standard drill may be a better choice. A drill press is a type of drill that may stand on the floor or be mounted on a workbench. The base of themachineis bolted to the table or floor and a column rises up from the base to support the back of the head of the drill. The column also supports a table that can be adjusted in height between the head and the base.The spindle, a metal component that holds the chuck and drill bit, extends downward from the front of the head, parallel to the column. A larger distance between the spindle and column allows wood with a larger width to be drilled. An on switch triggers the spindle to spin and levers attached to the head of the drill press move the spindle and chuck to move up or down. Thesedrillingmachines are suited fo r accuratedrilling, because the bit is fixed and the work can be secured to the table with clamps or a vise. - Types Of Drill potato chipsDrill bits are tools used in making cylindrical holes. Various types of drill bits are designed for different uses. Drill bits are equipments or tools that are used in making cylindrical holes. Drill bits can also be referred to as a drilling machine. Drill bits are available in various drill types such as metal drills, gun drills, screw machine drills, core drills, step drills, spade drills, forstner drills, masonry drills, dental or operative drills, wood bits, twist drills, drill blank taper drills and much more. They are designed to cut while doing a clockwise rotating motion. Several drill bits are coolant fed.They contain a channel or hole for enjoin the coolant fed near to the cutting edges. The split point drill heads of drill bits are used for chip clearance and for excellent centering. Drill bits can also be used in cutting aluminum, g eneral-purpose metals, brass, copper, bronze, ceramic, and plastic, harmless steel, steel, wood, titanium and hardened materials. Various types of drill bits are designed for different uses. Listed below are some types of Drill pusss. Twist Drill It drills holes in plastic, metal and wood. This drill is currently produced with a width covering a range from 0. 5 millimeters to 100 millimeters while its length is around g-force millimeters. The most usual twist drill has a tip angle of 118 degrees. This is a proper angle for an extensive array of job. It also has a long series drill for extended length twist drills. It is not advisable to drill deep holes using this twist drill. Diamond Drill Bit This particular drill is used in the bathroom for update or remodeling. It is also used in redesigning your kitchen decoration. Furthermore, it is used on ceramic, glass, tile, limestone, dye glass, marble, fiberglass, porcelain, stone, slate and porcelain tile.When using this drill, the main concern is to obtain water at the edge of the drill bit. Drilling fiberglass may be done with or without water but make sure that the fiberglass has ample amount of water just to get the drill wet. Indexable Drill Bit This provides an excellent performance in making short-hole drillings. Stainless steel is drilled 3x in diameter and only a short-hole must be done. Listed below are some other types of drill bits Adjustable Bit This is built with a changeable cutter blade to bore holes of various sizes. It is also used for drilling gaps for wiring or piping.Around-the-corner bit It is used to cut arched holes that are stretched in corners with a diagonal cutting surface. gimlet Bits This drill creates drill holes in wooden materials. The drill ends have a screw head so that the bits may be self fed. Brad-point drill This drill looks almost the same as the usual bits but it has sharpen point to make wood drilling a lot easier. This drill has cleaner holes other than spade bits. C ounterbore The drill allows a screw to be driven under the wood outside. The holes that are drilled may be filled with a plug or wire.Drill Saw Bit It is used to cut holes such as wood and metal and can enlarge current holes. Countersink A drill that has an angled tip design that forms a slump in the screw head. Fly cutter This one is often used to cut circles in wood and other soft metals. The diameter of circles may be adjusted by changing the cutter blade setting. Hole saw It cut holes from one to six centimeters in diameter and has a center bit for directing the cutting blade edge of the saw. Reamer bit The tapered bit of reamer may be used on existing holes rather than to enlarge holes.Screw pilot bit This beautiful bit is used for drilling body holes. A pilot hole is used along with the countersink. Wire Brushes It use to remove rust and to clean up metal and is available either as a wheel or a cup with wire brush. Plastic bit This is designed with a tip so as to prevent spl intering when drilling plastic. It is important to reduce the speed and slowly drill the other side of the plastic. Plug cutter Use this to remove cylindrical shapes from the wood. It covers the screw using a small cylindrical plate. Tapping- Tapping is the process by which internal threads are formed.It is performed either by hand or by machine. Minor diameter of the thread is drilled and then tapping is done. Fig. 11 show the tapping processes. Fig. 35 Hand taps and tapping process using tap wrench Fig. 36 Various operations performed on drilling machine Work Holding Devices 1. Machine Table Vice The machine vice is equipped with jaws which clamps the work piece. The vice can be bolted to the drilling table or the tail can be swung around swung around. Fig. 13 shows the standard and swivel vice. The swivel vice is a machine wise that can be swivel through 360 on a horizontal plane. Fig37 1.Step Blocks These are built to allow height adjustment for mounting the drilling jobs and a re used with strap clamps and long T-slot bolts. 2. Clamps These are small, portable vises , which bears against the work piece and holding devices. Common types of clamps are C-clamp, match clamp, machine strap clamp, U-clamp etc.. Fig. 14 shows the correct and incorrect methods of mounting the work piece. Fig38 11. APPLICATION OF CNC MACHINES ? cutting ? drilling ? milling ? conjoin ? boring ? bending ? spinning ? pinning ? gluing ? sewing ? routing Its application in some industries like -Automotive Industry Aerospace Industry -Machinery Industry -Electrical Industry -Instrumentation Industry Automotive Industry Different Products Fig39 Aerospace Industry Aircraft Turbine Machined by 5-Axis CNC Milling Machine Fig40 12. ADVANTAGES AND DISADVANTAGES OF CNC -Ease of Use ? CNC machines are easier for beginners ? Operation of several CNC machines at same time ? Some CNC machines dont need any operator indeed call their operator in case of the emergencies. High Efficiency ? operate almost continuously 24 hours a day, 365 days a year. Expanding Options ? Expand the machines capabilities with SoftwareChanges and updates. No Prototyping ? new programmers provide elimination build a prototype, save time and money. Precision ? part are identical to each other. Reduce Waste ? Reduce waste as errors allows minimize wasted Material. Disadvantage of CNC Machines Cost CNC machinery ? costs instead a lot more than conventional machinery. ? Does not eliminate the need for expensive tools. ? Expensive to repair. 13. CONCLUSION CNC machines which are applicable any type of processing. manufacturing anything is identical in shorter time. CNC machines provide many advantages. Many industries prefer using CNC machines.