This document provides information about a CNC machine that can operate in both milling and lathe modes. It describes the processes and controls for each mode of operation. Experimental procedures are outlined for performing turning, milling, and programming operations on the machine. CNC programming concepts such as coordinate systems, input modes, coding, and prerequisites are also discussed at a high level.

1. ferent modes/functions could be provided by this machine
1. Mill MODE
2. Lathe MODE
Mill Mode:
In Mill mode operation the work piece is in tool post and tool is in spindle and the work
piece can be moved in three directions (X, Y, Z).
Lathe Mode:
In lathe mode the work piece is in spindle and tool in tool post and there are eight
position for tool, four are for periphery and four are for axially.
In lathe mode the tool post can be moved only in X and Z direction
MACHINE CONTROLS:
3D CAD CAM centre is controlled by the help of different control buttons and programs.
Among them following are the most important;
1. Spindle control:
 Spindle forward
 Spindle reverse
 Spindle stop
2. Feed Speed Control:
It control the tool feed speeds in the X,Y,Z axes from 0 to 100% in 10% increments.
3. Jog axes control:
There are five buttons which controls manual movement of the table in the X and Z axes. These
buttons provide the rapid movement in the indicated direction.
4. Manual:
This button used for manual mode. When light ON the machine is operated by control panel and
when we press MAN button light goes turn OFF and machine operate by computer (automatic
mode).
5. Coolant:
This is used for controlling machine’s inner temperature.
6. Feed Hold:
It Acts as an interrupt control to the program and also preventing any further tool movement until
it canceled.
7. Single Block:
It is the automatic mode controlled from the pc when machine is running. This allows the
operation of only a single block (line) of the program at a time.

2. 8. Cycle Start:
It sets the automatic model and starts the machining from the PC program.
9. Power ON/reset:
Power ON switch is used for machine start and reset is used for any trip out.
10. Turret index:
This is used for turret tool holder into the next tool position.
11. Emergency stop:
This button used for emergency purpose.
OPERATION:
 First a design is drawn using design software in the
Computer attached.
 Secondly this program is converted into the machine
codes.
 A command is given to the machine to process
according to the set of instructions.
 Feed rate and spindle speed is specified in the
program.
 The processes could be also accomplished by manual
operation.
 Manual operation needs a professional to be skilled
one
EXPERIMENT NO.3
Title: To Perform Turning Operation in Lathe
Mode
CONVERSION MODES: In order to perform the lathe operation, if the machine is
currently in the milling Mode then we need to convert the Mode of operation from
milling to lathe mode.
This involves the following steps;
 To clamps the tool post
 To insert the work piece in chuck that is rotated by the spindle revolution
Theoretical Background:
Turning:
Turning is a machining process in which a cutting tool removes material by
moving more or less linearly while the work piece rotates. The tool's axes of movement

3. may be literally a straight line, or they may be along some set of curves or angles, but
they are essentially linear.
Turning Types:
 Facing
 Contour turning
 Chamfering
 Cutoff
 Threading
Operational steps:
 First the conversion from mill to lathe mode is done
 Then a work piece of Teflon is clamped tightly in the
chuck
 The cutting tool is clampsed in the tool post
 A sketch for the taper turning is drawn in the software
 The machine is turned on
 The command is given to the machine to start the operation
EXPERIMENT NO.4
Title: To Perform Milling operation on CAD CAM CENTRE
CONVERSION MODES: In order to perform the milling operation, if the machine is
currently in the Lathe Mode then we need to convert the Mode of operation from Lathe to
Milling mode.
This involves the following steps;
 Removing the tool post and adding the Machine vice for holding the work
part.
 Inserting the tool in the chuck that is revolved by the spindle.
THEORATICAL BACKGROUND:
MILLING: Milling is a machining operation in which a work part is
fed past a rotating cylindrical tool with multiple cutting edges. The
axis of rotation of the cutting tool is perpendicular to the direction of
feed. The cutting tool in milling is called milling cutter and the
cutting edges are called teeth.

4. Milling types;
1. Peripheral milling
 Cutter axis is parallel to surface being machined
 Cutting edges on outside periphery of cutter
 It involves the following operations;
o Slab milling
o Slotting
o Side milling
o Straddle milling
2. Face milling
 Cutter axis is perpendicular to surface being milled
 Cutting edges on both the end and outside periphery of the cutter
 It involves the following operations;
o Conventional face milling
o Partial face milling
o End milling
o Profile milling
o Pocket milling
o Surface contouring
OPERATIONAL STEPS:
 First the conversion from lathe to mill
mode is done
 Then a work piece of Teflon is clamped
tightly on the table.
 The end mill cutter is fixed in the jaws of the chuck tightly.
 The safety door is closed and the machine is started.
 After that appropriate depth of cut is given visually.
 The depth is in z-direction.
 Then spindle is started and feed perpendicular to the axis of rotation is given to the work
piece i-e in x-direction.
 In this way face milling of the material is
performed.
AUTOMATIC OPERATION:
PROGRAM & SEQUENCING:
Cutting dia: 7.00mm

5. Feed: .05 mm/rev
Spindle speed: 10000 rpm
Target or reference point of tool;
x = 0, y = -50, z = +10
units = millimeter
Program:
NOO1 G21 G90 G92 X0 Y-50 Z10;
NOO2 G00 X70 Y30;
N003 G01 G95 Z-15 F.05 S1000 M03;
N004 G01 Z10.0;
N005 G00 Y60;
N006 G01 G95 Z-15 F 0.05;
N007 G01 Z10;
N008 G0 X120 Y30;
N009 G01 G95 Z-15 F 0.05;
N010 G01 Z10;
N011 G00 X0 Y-50 M05;
N012 M30;
(End of program and stop working)
EXPERIMENT NO.5
Title: Programming in CNC
TheoreticalBackground:
COMPUTER NUMERICALLY CONTROL (CNC):
ComputerNumerical Control isthe control of amachine tool usingnumbersandletters. It is a system in
whichprogrammed numerical values are directly inserted and stored on some form of input medium,
and automatically read and decoded to cause a corresponding movement in the machine which it is
controlling.
ADVANTAGES OF CNC:

6.  Reducedscrap.Errors due to operator fatigue, interruptions, and other factors are less
likely to occur.
 Simplifiedinspection.Once the firstpiece has passed inspection, minimal inspection is
required on subsequent parts
 Lower tooling costs due to less need for complex jigs and fixtures.
 Reduced lead time.
 Complex machiningoperationsare more easilyaccomplisheddue to advanced machine
control.
 High degree of quality due to accuracy, repeatability, and freedom from
DISADVANTAGES OF CNC:
 Tools on NC machines do not cut metal any faster than conventional machines.
 NC does not eliminate the need for expensive tools. There is also a greater initial cost
involved with the NC machine.
 NC will not totally eliminate errors. Operators can still fail to push the correct buttons,
make incorrect alignments, and fail to locate parts properly in a fixture.
 Selection and training of programmers and maintenance personnel is required.
Pre-requisites for CNC programming
1- Cutting Data and Formulas
Here are some of the most common terms used for expressing cutting data:
 Spindlespeed - Spindle speed is the rotational speed of the spindle and tooling. This value is
usually expressed in RPM. (Revolutions Per Minute)
 Feed rate value - The feedrate value isthe numerical value atwhicha tool will traverse a work
piece. It is usually expressed in either IPM(Inches Per Minute) or IPR (Inches Per Revolution).
 Cuttingspeed - Cuttingspeedisthe rotational speedof the cuttingtool or work piece. It can be
stated as either RPMor SFM. (Surface Feet Per Minute)
 Depth of Cut - Depth of cut is the distance the tool tip is engaged into the work piece. It is
incorporated into the X, Y, and Z values in a CNC program.
2- Blueprint Reading
Blueprintreadingisabasicskill inthe manufacturingindustrythatall engineers, managers, CNC
programmers,CNCoperator,machinists,andinspectorsshouldknow inmanufacturingindustry.

7. 3- Operations Sheet:
The operations sheet, or setup sheet, is used to
describe the processes needed to machine a
part on a CNC machine. Each process is
written out in the proper machining sequence
and includes the tool to be used and all
cutting data. Programming the outer contour
is one operation in the machining of a part. To
accomplish this you must first have a part
origin. Then, the points required for
machining would be calculated for the center
of the tool to be used, offset the radius of the
tool, from the actual part edge coordinates.
Unit Systems and Input Modes
Unit Systems are the units of measurement to be used for the CNC program. All machines understand
both English and Metric standards. When programming in english units you are using inches. And in
metric its the millimeter (mm.). The CNC machine needs to be told which units are being used. Some
machinesare automatically set-up at the factory for inches or mm. normally at the beginning of a CNC
program you will see either; G70 to specify inches or G71 to specify mm.
Input modes refer to the type of coordinate information that is input into the program for the CNC
machine. There are two types.
 Absolute input,designatedbythe G90 code,specifiesdistancesfromthe originorprogram zero
point. Absolute is the most common mode.

8.  Incremental input,designatedbythe G91 code,specifiesdistancesand directions based on the
previouspointasan origin.Incremental inputissometimecalledpoint-to-point.All CNCsystems
can be switched from absolute to incremental mode and back unlimited times within a
program.
Other input modes such as Helical also exist.
Letter Code Descriptions
N Sequence Number
G PreparatoryFunctions
X X AxisCommand
Y Y AxisCommand
Z Z AxisCommand
R Radiusfromspecified center
A Angle CCWfrom+X vector
I X axisarc centeroffset
J Y axisarc centeroffset
K Z axisarc centeroffset
F Feedrate
S Spindle speed
T Tool number
M Miscellaneousfunction
Absolute
40,40
Current
positionof
tool
20, 20
20,20
Incremental
Nextpositionof tool