CNC Programming Series-5

G00 D0X0Z0G15X0Z0
G00 T1D1
G00 X26Z0F100
G00 X23.50
G33 Z-25K2.5F10
G00 X26
G00 Z0
G00 X23
G33 Z-25K2.5F10
G00 X26
G00 Z0
G00 X22.50
G33 Z -25K2.5F10
G00 X26
G00 Z0
G00 X22
G33 Z-25K2.5F10
G00 X26
G00 Z0
G00 D0X0Z0

CNC Programming Series

CNC Programming Series-4

G00 D0X0Z0G75X0Z0
G01 X-1F70
G01 X22
G01 Z-25
G00 X27Z0
G01 X20
G01 Z-25
G00 X27Z0
G00 D0X0Z0

CNC Programming series

CNC Programming Series-3

G00 D0X0Z0
G00 X22Z0F100
G01 X-1F70
G01 X18
G01 X20Z-25
G00 X22Z0
G01 X16
G01 X20Z-25
G00 X22Z0
G01 X15
G01 X20Z-25
G00 X22Z0
G00 D0X0Z0 

CNC Programming Series

CNC Programming Series-2

G71 G94
G00 D0X0Z0
G00 X27Z0F70
G01 X-23
G01 X-25Z-2
G00 X27Z0
G00 D0X0Z0

CNC Programming Series

CNC Programming Series-1

G00 X0Z0
G00 X38Z0
G01 X33
G00 X38Z0
G01 X30
G03 X35Z-10CR17F10
G00 X38Z0
G01 Z-10
G01 X35
G02 X35Z-30CR20F10
G00 X38Z0
G00 D0X0Z0

CNC Programming Series

vmc machine Constructions

VMC Machine Constructions- 

vmc machine consists following parts -

1. vertical spindle head
2. Table transverse
3. head stock assembly of machining center
4. Automatic tool changer (ATC)
5. Machine control unit (MCU)
6. machine body
7. CNC electrical Board
8. Machine Table
9. Guards
10. Interface

1. Machine body - 

Machine body is made of cast iron. CI has excellent vibration absorbtion capacity. Saddle is fitted on the base of the machine to hold machine table. Machine base, saddle and column is made of cast iron. Column is also fitted on the machine body. Machine table takes all the movements on the guide ways and ground ball screws driven by a servomotor through belt drive. The main spindle of cnc machine runs on angular contact ball bearing which is fitted into the head stock. Main spindle is rotated by servomotor and it is connected to motor through direct coupling.

2. Head stock -

It made of cast iron. It is filled on vertical columns. Horizontal & vertical ribs are added in headstock to provide more strength.

3. Spindle -

It hold the machine tool.Spindle is made of case hardening or nitriding steel, It provides rotational speed to the machbine tool according to instructions of machine cotrol unit.

vmc machine

4. Column -

It is made of cast iron. horizontal and Vertical ribs also fitted to the care of torsion and bending moments. Bearing is fitted to the columns.

5. CNC Electrical Board -

It consists electrical pannel and drives. Control pannel's elcetrical board is mounted on in front of the machine while drive is situated in the back side of machine.

6. Coolant system -

It is used to store the coolant for operation. Coolant helps to reduce heat.

7. Saddle -

Saddle is mounted on the machine base. Saddle consists cross slide, guideways, ball screw, bearings, pulley, motor.

8. Column assembly -

It is hollow verticalstructure and is heavily ribbed. Horizontal ribbed is placed to escape from twistingmoments. Vertical ribbedescape from the bending moments. Guideways is also mounted on the column.

9. Tool magzine -

Tool magzine consists a number tools

10. Interface is used to input the data in machine and output the data from machine control unit.

How Numerical Control (NC) Machine works

NC Machine -

As we know that Numerical Control Machine is operated through automation.These machine works on instructions which control by programme which consists Number, Alphabet and different type of sign. NC Machine has a control unit which analysis the data received from input and convert into work.

NC Machine has a systematic working style which is as given below-

1. Firstly, We prepare a programme according to need of drawing. These programme is prepared by        using Number, Alphabet and different type of sign.

2. Now feed these programme in the memory unit of machine throw input device.

3. In NC Machine, Punch tape is used to store the  data. Paper tape is mostly used to store the data.          Some others paper-mylar, aluminium-mylar and plastic tapes are also used to store the data.

4. Tape reader is used to read the data from punch tape.It converts the data into electrical signal by           decoding of block of any problem .

5. Tape reader send the electrical signal into machine control unit after decoding the data.

6. Machine control unit converts these electrical signals into energy form and send to the driving            control unit which works on the information store in the programme different type of servo motor      rotates according to received electrical pulses.

7. Machine table is rotate with the help of lead screw. Machine table can be control by controlling           the electrical pulses.

8. Close loop control system sends the feed back of table actual movement and desired movement          through feed back sensors

9. In NC Machine, AC,DC and Hydraulic servo motor is generally used.

1. cnc machine  - -

2. NC machine - 

3. cad/cam/autocad -

4. cnc machine tool -

cnc turning machine operations and Applications

cnc turning machine operations -

cnc is the short form of computer numerical control machine.  As we know this is autonomous control machine in which all operations are done automatically.There is no need of manual control.  We feed up the instructions in the form of programme that executes the work. CNC Machine is capable to do a lot of work in manufacturing industries. It is used in also other industries but mainly used for the manufacturing industry.CNC Machine has a wide range of applications in different industries. In manufacturing industries by the help of cnc machine many operations can be done on time with high accuracy.
Some imporatnt operations done by on cnc machine is given as below -

cnc machine turning operations

1. Drilling Operation - In this process, cnc machine is used to do hole  in the job.

2. Facing Operation- In this operation face of the job is done uniform.

3. Boring Operation- It is used to increase the size of hole.

4. Reaming Operation- Used to make the size hole true.

5. Tapping Operation- Used to cut internal thread on the job.

6. Threading Operation- Used to cut external thread on the job.

7. Taper turning Operation- In this operation different diameter of a cylindrical job is prepared .

8. Form turning Operation- Used to prepare different shapes and size of jobs.

9. Knurling Operation- Knurling tool is use to make different shape grove on the job.

10. Parting off Operation- Used to divide job in two parts.

11. Chamfering Operation- It is a transitional edge between two faces of the jobs.

12. Grinding Operation- By using a special types attachment on CNC Turining machine we can do                                              grinding operation.

13. Spring winding Operation- In this operation coile is made by CNC machine.

CNC Turning Machine Applications -

CNC Turning machine is used in the wide range of industries because of  less machining time, High productivity and High accuracy. Some are as given below-

10. Core sector industry

Read Also -

1. cnc machine  -

2. NC machine -

3. cad/cam/autocad -

4. cnc machine tool -

CNC Machine Tool - Characteristics, Types, Material, Affecting factors

CNC Machine Tool –

Tool is used to cut the material for making job. A large variety of tool is used in CNC/VMC machine. A good tool for CNC machine helps to improve the productivity of machine.

In this article, we will discuss following points on CNC cutting tool –

· CNC machine tool characteristics

· Factors affecting the tooling for CNC machine

· Types of CNC tool

· Material of CNC tool

1. CNC machine’s tool characteristics –

 A good CNC machine tool should have following characteristics –

· Rigidity of tool should be high that withstend higher cutting forces.

· Melting point should be high

· Tensile strength should be high

· Fusibility of CNC tool should be high

· Fatigueness of a good CNC tool should be low

· A good CNC tool should be with high accuracy

· Wearness should be low of a good CNC tool’

· Oxidation should be low

· Hardness and toughness should be high

2. Factors affecting two tooling for CNC machine-

 There are give some important factor which affected the life of CNC machine’s tool-

· Materials of job

· CNC machine type

· Required operations

· Cutting path
 . Production schedule

· Complexity of operations

· Skills of operator

cnc vmc machine tool

3. Types of Cutting tools for CNC machine – 

The cutting tool of CNC machine can be classified in many ways. But there are three way in which basis we can classified CNC machine tool –

(A) On the basis of CNC tool construction-

· Solid CNc tool

· Brazed CNC tool

· Inserted bit CNC tool

(b) On the basis of CNC tool materials-

· High speed steel (HSS)

· High carbon steel (HCS)

· Cemented carbides

· Coated Carbides

· Ceramics

· Silicon

· Diamond

· Born Ni tride

(c) On the basis of setting up of CNC tool –

· Pre-set CNC tools

· Qualified CNC tool

A. On the basis of CNC tool construction –

· Solid CNC tools- Generally there tools are made of high speed steels (HSS) and high carbon steel (HCS)

Characterstic – 

(a) High tensile strength

(b) High cmpressive strength

(c) Low war resistance

(d) High finishing

These Cnc tools have to grind regularly due to this they in crease the production time.

(ii) Brazed Cnc tools-: These tools are made trough forged process. It has forged shank of high tasile strength.

(iii) Inserted bit cnc tools-: These typs tools cnc machine. Tool change (grinding) time is high for solid cnc tool and brazed cnc tool as compared to inserted cnc tools .So these are used widely. Harden and special grade carbides must be used to achieve faster rate of metal removal. The index able inserts of tungsten carbide are further coated with a wear resistance layer of titanium carbide or titanium nitrite for desired results.

(B) On the basis of cnc tool materials-:

HSS tool material have quantities of tungsten(14%-18%),Molybdenum,chromium (3.5%-4.5%), Vanadium (0.5%-1.5%), and carbon (0.7%-0.9%). The mixture of tungsten molybdenum and chromium distributed through out the metal matrix provide very good hot hardness and abrasion resistance. The major alloying elements generally used in HSS tool is tungsten and molybdenum. Tungsten is costly, but molybdenum is cheap but has higher toughness. For same Hardness there care need to be exercised in hardening as decreasing taken place in molybdenum steels. It have narrow temperature range for heat treatment.

Characterstics of HSS-:

(a) High hardness

(b) Good wear resistance

(c) High toughness

(d) Reasonable cost.

(e) Suitable for high cutting speed

(ii) High carbon steel (HCS) -:

 HCS is the medium cutting tool and suitable for low cutting speed. They have good cold toughness but have low, at high temperature. Hardness of these tools depends on the presence of carbon quantity

(iii) Cemented carbide-:

 Cemented carbide are produced by cold compaction of the tungsten carbide powder in abider such as cobalt followed by liquid phase sintering. They are widely used in industries on cnc machines. It mostly contain tungsten (81%) Cobalt (13%) and carbon (5%).

Characterstices -:

(a.) Has high hardness, so caused on high speed

(b.) Cobalt content increase, toughness and impact strength of cemented carbide tool but decrease hardness and thermal conductivity.

(c.) Five grain carbides are harder compared to coarse grain carbides.

(d.) Multi grain carbide grades increase chemical stability, hardness and hot hardness.

(e.) These cnc tool has high brittleness.

(iv) Coated carbide-: 

Coated cnc cutting tool has two or three times like more as compared to uncoated tools. So use of these types tool is increasing day by day in industries. These coating such as aluminium oxide, titanium nitrite titanium carbide etc. are deposited generally on the carbide tool bits by using chemical vapour deposition process.

Characteristics -:

(a.) Life cycle is high

(b.) can used on high cutting speed easily

(c.) Have broad use for different machining process.

(v) Ceramics-:

 The materials like boron carbide, silicon carbide, aluminium carbide, titanium carbides are known as ceramics. These are prepared by sintering the elements at high temperature. Ceramics tools should be used with very high cutting speeds on steels. They are neither suitable for low cutting speed nor for intermittent cutting. Cutting fluid if applied should be in flooding with copious quantity of fluid to thoroughly wet the entire machine zone, as ceramics have very poor thermal shock resistance.


(a.) High compressive strength.

(b.) High resistance to oxidation.

(c.) Desired hardness at low and high temperature.

(d.) Poor thermal conductivity

(e.) Non-magnetic and non-conducting to electricity

(f.) These can not be wetted by molten meta

(g.) Longer tool life

(h.) Long built-up edge.

(i.) Lower coefficient of friction

(j.) Good machining & flexibility

(vi) Silicon-: 

This is tougher cutting tool material which is used to get high surface finishing. This is tougher than alumina involve interrupted cuts.

(vii) Diamond-:

 Being expensive material, its application is restricted to specific cases only in metal machining small diamond bits are used for precise jobs such as finishing operation on hard steels. 

Read Also - 

(C) On the basis of setting up of cnc tool-:

(i) Preset cnc tool-: This type tools is positioned in tool holdres in such a way planned in advance to ensure a continuous production cycle. These are loaded before start the programme or production in cnc machine at a particular position.

(ii) Qualified tools-: These types tool is fitted into a required edges is accurately positioned within close limits relative to a specified datum on the tool holder or slide is known as qualified tool.

Read Also - NC Machine -

Safety Precaution for CNC Machine

Safety Precautions- 

Today conventional machine, is automated, it generates the complex technical system as well as new hazards. Automation of machine is controlled through computer, numerical control system. To escape from the hazards in these new complex system, we should fallow the instructions carefully.Learn what to do and what not to do when you work on CNC machine. It keep way from the accidents. Safety should be main concern for any company. It save the life of their valuable worker.

CNC machine is a manufacturing process  in which  pre-programmed instructions through  computer software control two movements  of tools and machinery. Operating the CNC machine without proper shill and knowledge we can invite accidents. So during the working on CNC machine we should follow some instructions. Some important instructions are given as below-

cnc vmc safety



CNC machine -

NC machine -

Safety precautions for CNC Machine-:

  •  Never touch rotating part of machine.
  •  Do not touch any voltage terminal.
  •  Do not touch or press any button without knowing when machine is in operation.
  •  Always switch  off the main circuit beaver after the operation.
  •  Never put the machine under vibrations.
  •  Do not open cnc machine door during operation.
  •  Always use the safety shoes during working on cnc machine.
  •  Use insulator under the machine.
  •  Never wear  loose clothes during working on cnc machine
  •  Remove oil from the floor around the machine.
  •  Installed the cnc machine at separate place.and provide proper area to work.
  •  Clear the chip in between the production process.
  •  Ensure the job is firmly fitted on the machine. also check the tool holder.
  •  When loading/unloading work piece ensure spindle of machine is stopped.
  •  Ensure that cnc machine is installed rigidly and securely with proper insulator.
  • Check the programme accuracy with the help of simulation before running the programme.
  • Check the lubrication and oiling regularly.
  • All maintenance work should be done with the power off.
  • Check the main pressure and clamping pressure before running the programme.
  • Check the speed over the ride position.
  • Do not use compressed air for cleaning.
  • Check the sliding movement before operation.
  • Always make sure CNC machine isn't in working condition when you load the tool magazine.
  • Make sure correctly tool is loaded in magazing.
  • Test the tools before the use.
  • Set the spindle direction according to requirement of job.
  • Never use blunt, cracked and chipped tools.
  • In CNC router, ensure there are not any screws in the path of bit.
  • Use the emergency button during any misbehaving. By using emergency button CNC machine can be shut down instantly.
  • Use the curtain guards which are made from PVC. These help to protect from airborne chips.
  • Always wear the personnel protective equipment during the working on CNC machine.
  • Keep a distance from the moving parts of machine.

How to make CNC/VMC Programme -




These are the terms with which one come across in the market. CADD which stands for Computer Aided Design and Drafting. In short this is termed as CAD. This involves any type of design activity which make use of the computer to develop, analyze, or modify an engineering design. It can be used to supplement or replace traditional drafting and designing tools i. e. scales, compass, T-square, drawing board etc. CAD ensures zero defect engineering.

The CAD system consists of a CAD software, a processor or a computer, a monitor used to display drawings, a keyboard  for data input, device such as mouse or stylus to control the location of drawing objects and a plotter or printer to take a hard copy output on paper.

The CAD operator interacts with the system with the help of series of commands to create, modify and edit a drawing. The software provides with predefined geometrical objects ( called objects or primitives) i. e. line, arc, circle etc. for 2D drafting and box, cylinder, cone etc. for 3D modeling. Operator can feed in the desired dimension to create the required objects and using an input device locate points to place objects on the screen. Combined with a library of symbol for repetitive work, it can reduce the lead time to complete a design project to few hr. as compared to weeks with manul designing.

Some high-end software allows user to perform engineering analysis on 3D models generated. The analysis may involve stress-strain calculations, heat transfer computations, analyzing dynamic behavior of a component, and calculation mass properties. The output of the analysis can also be presented graphically on the screen. This feature avoids creation of costly prototypes and time and money spent to analyze them. Design can be reviewed, evaluated and compared easily on the computer after the designer is through with the analyzing part.
Some of the graphics features of CAD system lend themselves especially well to the drafting process. 
These features include automatic dimensioning, generation of crosshatched areas, scaling of the drawing, and the capability to develop sectional view and enlarge views of particular part details. The ability to rotate the part or to perform other transformations of the image i. e. move, scale etc. can be of significant assistance in drafting.

Advantages of CAD are as follows :-
  1.            Better Designs.
  2. ·         Improved engineering productivity.
  3. ·         Shorter lead times.
  4. ·         Improved accuracy of design.
  5. ·         Provides better functional analysis to reduce prototype testing
  6. ·         Standardization.
  7. ·         Better documentation.
  8. ·         Better costing.
  9. ·         Faster and accurate NC Part programming with CAD Data.
  10. ·         Improved productivity in tool designing.
  11. ·         Better communication interface among engineers, designer, drafters, management and different project groups.

Read More About CAD -


                CAM stand for Computer Aided Manufacturing. This is use of computer systems to plan, manage and control the operations of a manufacturing plant through either direct or indirect computer interface with the plants production resources. In direct interface, computer is connected directly to the manufacturing process for the purpose of monitoring and controlling the process.
With the introduction of CAD and CAM, design and production department of industries have come closer, which used to be two far away departments earlier. CAD system allows designers to create, visualize draft and analyze their products on the screen in two or three dimensions. The same data can be transferred to production engineering as manufacturing data base. Production engineer can utilize the data to generate numerical part programming for CNC machines or for robotics etc. CAM system oversees the work flow on shop floors and controls the machine tools, conveyors and robots responsible for production.


                CAE stands for Computer Aided Engineering. It ties together such diverse interests as drawings, cost analysis, structural analysis, production process plans, material specification, tool design and quality control.

 What is AutoCAD

                             AutoCAD is developed and marketed by M/s Autodesk Inc. USA and most widely used CAD software worldwide. Currently releases of product are AutoCAD 2019. This was one of the software, which were launched on PC platform in initial years of eighties with few options. Before that all the CAD software used to be on mainframe machine only. Now it is one of the best selling software of the world. With AutoLISP, VB and VC++, accompanying high level programming languages, user can customize AutoCAD to their particular needs. A number of third party software are also evailable which work on AutoCAD platform to customize the software for specific usage i. e. Electrical, Civil, Architect, Piping, Ducting, etc.

Advantages of AutoCAD 

·         Flexible.
·         Availability on various platforms.
·         Availability and technical support.
·         Simple and ease of use.
·         Customizable.
·         Third party customized tools available.
·         Accepts and produces various file types.

Hardware requirement

·         Minimum Pentium 166MHz. Processor.
·         Minimum 32 MB of RAM.
·         VGA or higher graphics card.
·         Minimum 150 MB of free hard disk space.

Optional devices

·         Printer or plotter for hard copies.
·         Pointing device, mouse or tablet.
·         Color monitor or dual monitor.

Important commands of Autocad software   

  • Line: -The line is the basic object in AutoCAD. Line command allows you to draw straight lines by specifying two end points of line

    Xline (Construction Line):- Xline command draws lines of infinite length i. e. both ends remains invisible. Basic use of xline is to draw the construction line or grid lines used in layouts and construction drawings

    Mline(Multi-line):- Mline command creates multiple parallel lines at user defined distance. This is a shortcut to drawing a single line and then offsetting it on one side

    Circle:- Circle command allows user to draw the circle with different options. User may use any of the seven options available to draw the same circle, depending upon the type of data available and user personal preference

    Arc:- AutoCAD allows user to draw an arc with various options

    Polyline:- A polyline is connected sequence of wide line and arc segments. Polyline with all number of segments is treated as a single object by AutoCAD

    Polygon:- AutoCAD polygon command allows user to draw a polygon by specifying number of sides and length of sides

    Rectangle:- A rectangle is a special from of polyline which can be created by specifying two diagonally opposite corner points

    Ellipse:- AutoCAD RI. 14 allows user to create true ellipses with ellipse command

    Remove:- Remove option allows user to remove objects form selection set

    Add:- Add option allows user to add more objects to current selection set

    Erase:- Erase command allows user to erase the object, which are not required, from the drawing

    Copy/Move:- Both copy and move command work in similar fashion. With copy command user gets a duplicate copy of selected objects at required location while move command actually move the selected objects to new defined location

    Offset:- Offset command allows user to create objects parallel to the existing objects by defining the offset distance or through a specified point. User can quickly create the lines of similar length at defined distances and concentric circles of defined offset radius values with offset command

    Mirror:- Mirror command lets the user create a mirror copy of selected object. User will have to locate the mirror by specifying two points on mirror line. User can place mirror anywhere in the drawing. AutoCAD obeys the basic law of mirror that distance of image from the mirror line stands equal to distance of original object from mirror line

    Array:- The array command allows user to make multiple copies of selected objects in defined formats

    Fillet:- Fillet command removes the sharp edge corners of two objects and connects them with a smooth arc of defined radius

    Chamfer:- Joins the two line objects (only) with a straight line

    Trim:- Trim commands trims selected objects, which are projected out from an edge

    Extend:- Extend command lengthens the selected objects till the selected edge

    Rotate:- Rotate command allows user to rotate selected object around a specified base point

    Scale:- Scale command allows user to change the size of existing objects equally in both the coordinate directions

    Break:- Break command allows you to remove a portion of an object. You are prompted to select one or two points (depending upon the option) on the objects and AutoCAD removes the portion of object within the selected points

    Pedit (Polyline Edit) :- Pedit command edits the existing polyline with following options

    Join :- Prompts to select objects

    Zoom :- AutoCAD provides zoom command to take a closer look at required part of the drawing

    Pan :- Pan command you can displace whole drawing on one side and bring required area on the screen. All you have to do is pick two points on screen or specify coordinates of two points to specify the displacement. AutoCAD calculates the distance and angle between two points and performs displacement

    Regen :- The REGEN command regenerates the entire drawing and redraws it on the screen. Regeneration of drawing is reading the data from the database of AutoCAD and drawing it on the screen, which is same as opening a new file

VMC Programe -  Reactangular slot cutting Programme -

CNC Lathe Turning Operation Programme -

Numerical control (NC) machine - Introduction, working, elements

Numerical Control Machine – 

NC machine stand for numerical control machine
Numerical control machine may be defined as a method of automation in which machine tools is compelled by letters, numbers and symbols. Combinations of these letters, number and symbol is called program. The program consists instructions about the process of manufacture and movements of tool. Programme describes tool path, feed, speed etc. of the tool. Since program is the controlling point for job manufacturing, the machine becomes versatile and can be used for any part. Functions of any cnc machine tool is controlled through electronically, hydraulically and pneumatically.

Classification of NC machine-

NCsystem can be divided in 3 parts based on their position              control system. These three systems are as below-
(1) point to point system (2) straight cut system (3) contouring system


 (1) point to point system-  This is the simplest control system of NC machine in it, tool travel                     parallel to one axis ( x or y axis ) by using, this control system simple machining operation                 like drilling operation.
(2)  Straight cut / straight live system - In this system, tool travels along with a straight live in any             particular axis. Straight cut milling is done by this system. Some of uses machining  live face               milling, pocket cutting, step turning is also control by this system.

(3) Contouring system - In this control system, tool moves according to required shape of job.                  Tool  job both will be in inter-related motions on different co-ordinate  axis. In this system,                   control unit monitor all the movement of machine by closed loop feed mechanism. This system          is used to design complex job shape & size.

 Main Element of NC machine-

Main parts of NC machine is as below -
 (1) Input unit- used to send command from operator to control unit of machine. Input unit                      change the signal into digital from by using A/D converters. Input unit stored the data in the                paper  tape till not required of the machine control unit. Instructions is fed up in machine in                  the form of programme.
 (2) Memory unit- It stored the data received from input in the form of code is called programme.                                                                                                                         RAM is used to store data.
 (3) Punched Tape- It is used to store the data in machine magnetic tape, disk is used in magnetic                 device
(4) Control unit- This unit receives the instructions from the memory unit of machine and inter                 prates them. This is the main part of NC machine. It process the all data receive from input unit           to do work operations. It controls the machine speed.

(5) Algorithm unit- This is main unit of the machine.

 (6) Output unit- It receive the data from memory unit on the permission of control unit and then                convert digital signal into analogue then control the servomotors axis drive. Output unit is mainly          used to move positions of axis.

CNC Machine



Control System of NC machine-

Two types of control system is used in NC machine which are as below-

(1) Open Loop System
(2) Closed Loop System

(1) Open Loop System - This type machine system has controlled on the movement of slide. No feed back system is present in open loop system. So it is not possible to put slide position right position through feed drive. In this system we can not compere the output of machine with input. In this system, tape reader reads the all instructions which are stored in taper through decoding. Then tape reader converts two all information into electrical signal. This signal is send to machine control unit. Machine control unit sends signal according to instructions / programme to the driving control unit. Driving motor rotates according to electrical pulses signal. Machine table is rotated with the help of lead serew. Every electrical signal rotates the pulses motor by friction that is called stepping angle. Machine table is also controlled by these electrical pulses signal. Open loop system is used in point to point system.
(2) Closed loop system-
                                                This system has feedback control system. Closed loop control system is used high setting accurated machine. Slide displacement is measured by a monitoring device. Slide position is regulated by servo system when it comes in required position and then compare with input information. Machine table's displacement is compared with input through feedback sensor. In closed loop system AC. DC and hydraulic servo motor is used to work

Terms Used in cnc machine programming- 

CAD - Full Form, Introduction, Functions

CAD Software

CAD is stands for computer Aides Design

CAD is used to create 2- D (dimensional) , 3-D drawing and model. CAD is used in manufacturing industry to draw various product  design. CAD software is also used in electrical engineering and in civil engineering.

CAD – CAD is stands for computer aided design. In computer aided design we basically take of integrating computer science technique with for engineering design. So computer aided design software utilities the computer as a tool for all functions that are involved in the design process.

Computer aided design software functions-

    1.    Engineering drawing
          2.    Individual component modelling
          3.    Layout design
          4.    Assembly modelling
          5.    Tolerance checking
    6.    Interference checking
    7.    we can calculate varions geometric properties on CAD software
          8.    There is no need to draw any drawing again and again because you can  copy drawing in                     cad software.
    9.    In cad software, it is easy to edit, replace dimensionor shaple and size. 

Input devices for CAD design software –

            1.  Keyboard
            2.  Mouse
            3.  Light Pen
            4. Tablet
            5. Scanner

Characteristics of good a cad software –

 1.      An efficient cad software will be use less responsive time and give better output
 2.    Cad software must be flexible that modification can be do easily in drawing
 3.      A cad software should be easy to operate
 4.    The cad software must be portable that drawing can be shifted easily from one system to other           system
 5.   A cad software must be reliable
 6.   A cad software must be recoverable that data can be recover easily after crash. Auto cad is                   mainly used draw manufacturing design

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Drafting is one of the first computer applications used by many a user in view of its law cost and easier adopt. Auto cad is by far the most widely used CAD software for drafting applications

    Some important command used in autocad as given below
  1.          New – To open a new drawing
  2.          Open – To open a old drawing
  3.          save – To save the current drawing
  4.          Draw - To draw a line, circle, polygon, rectangle etc.
  5.          Modify – To edit the drawing
  6.          properties – To change properties of drawing
  7.         Text – To write text in drawing
  8.         Units – This lets us set up the units in which auto cad would have to work
  9.          Limits 
  10.         Grid – It controls the display
  11.         Snap – It controls the resolution of the cursor movement
  12.         Ortho – It allows the user to control orthogonal drawing made
  13.         Zoom – It is used to change the scale of display
  14.         PAN – It allows to move display window in any direction without changing the display                   magnification
  15.         Move – It is used to move drawing entities from one location to another
  16.                Copy – It is used to copy the drawing.
  17.              Chamfer – It creates a bevel between two intersecting lines             at a given distance from            their intersection.
  18.                Filled – It connects two lines, arcs, circle with a smooth are of specified radius.
  19.              Offset – It makes a entity parallel to another entity.
  20.         Array – It makes multiple copies of selected object