Types of cnc machines

TYPES OF CNC MACHINES
GUIDED BY
RAGHUVAMSHI
ASSISTANT PROFESSOR
GITAM UNIVERSITY
7/14/2017GITAM UNIVERSITY BANGALORE
1
Presented by
B.V.S.K.SUMANTH
MECHANICAL BRANCH
7TH SEMESTER
GITAM UNIVERSITY

2 OVERVIEW
• WHAT IS CNC
• CNC MACHINE TYPES
• WORKING OF CNC MACHINES
• PROGRAMMING SOFTWARES
• TYPES OF CONTROL UNITS
• BREIF THEORY OF CNC MACHINES
• DIFFERENT AXIS SYSTEM
• G &M CODES
• ADVANTAGES
• DISADVANTAGES

WHAT IS A CNC MACHINE?
In contrast to the conventional Lathe machines where operators give input and
control the working, CNC machine is a machine which does machining process with the
help of computerized control units which give it instructions regarding:
1. Tool Control: Tool and tool parameters
2. Units, incremental or absolute positioning
3. Feed rate and spindle speed
4. Coordinate System
5. Coolant Control: On/Off, Flood, Mist
6. Coordinates: X,Y,Z
3

CNC MACHINES
TYPES
There are EIGHT different types of CNC machines as follows:
1. CNC Lathe Machine
2. CNC Milling Machine
3. CNC Router Machine
4. CNC Laser Cutting Machine
5. CNC Plasma Cutting Machine
6. 3-D PRINTER
7. PICK AND PLACE MACHINE
8. 5-AXIS MACHINE
4

WORKING
CNC working principle consists of following steps:
• 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/CAM by machine operators.
• G&M codes are automatically generated by the computer software
5

PROGRAMMING SOFTWARE
CNC machines use software to perform their work . They can do both 2D
and 3D processes on it. These codes are specified to do certain operations on the
lathe machines. These codes are arranged together to make a complete program
on the CNC machine. These programs then guide the machine to perform the
desired processes in an orderly manner.
6

PROGRAMMING SOFT WARES
For 3D works, we use certain software’s like:
1. Master Cam
2. Dell-Cam
3. Pro E
The software Pro E can even perform processes in 4D. The procedure is carried out
at first we make a drawing on CAD, convert it into CAM and then the machining is
done on the part being manufactured.
7

TYPES OF CNC CONTROL
UNITS
These are the major companies providing control units for the CNC machines to be
operated:
• SIEMENS
• MECH 3
• FANUC
• GSK
• Pentode
8

MILLING MACHINE
• Milling machines are often retrofitted with
CNC technology.
• The milling machines are also known as the
multi-tasking machines (MTMs) which are
multi-purpose machines capable of milling
and turning the materials as well.
• The milling machine has got the cutter
installed up on it which helps in removing
the material from the surface of the work
piece. When the material gets cooled down
then it is removed from the milling machine.
9
( Retrofitted refers to the addition of new
technology or features to older systems)

10
The two main configurations of the milling machining operations are the types of milling machines.
These are the vertical mill and the horizontal mill. They are further discussed below:
1.Vertical Milling Machines
 The vertical mill has a vertically arranged spindle axis and rotate by staying at the same axis. The
spindle can also be extended and performing functions such as drilling and cutting. Vertical mill has
got two further categories as well: turret mill and bed mill.
 The turret mill has got a table that moves perpendicularly and parallel to the spindle axis in order to
cut the material. The spindle is, however, stationary. Two cutting methods can be performed with this
by moving the knee and by lowering or raising the quill.
 The other is the bed mill in which the table moves perpendicular to the axis of the spindle and the
spindle moves parallel to its axis.
2.Horizontal Milling Machines
 The horizontal mill is also the similar cutter but their cutters are placed on a horizontal arbor.
 A lot of horizontal mills have got rotary tables that help in milling in various angles.
 These tables are called the universal tables.
 Apart from this all the tools that are used in a vertical mill can also be used in the horizontal mill.

• Just like milling machines, lathes are also
commonly retrofitted with CNC technology in the
exact same way.
• Use for facing, turning , reaming, drilling, finishing
etc.,
• Automatically operated with the help of G&M
codes
LATHE MACHINE
11

• CNC Routers are a very common piece of machinery you will see
a lot when learning about CNC.
• These are machines built exclusively to be operated by CNC
technology and typically have no human interface other than
through the computer.
• Routers are generally for producing larger dimension parts and
more commonly built with the idea of cutting wood, plastics and
sheet metal in mind.
• Routers also are most commonly found in a 3 axis Cartesian
coordinate setup (X, Y and Z).
• A 3 axis set up will allow cutting of profiles, pocketing and 3
dimensional relief machining.
• There are also CNC routers which are 4, 5 or even 6 axis (the
additional axes are rotary and used to rotate the tool around the
work piece or visa versa), these machines are more suited towards
cutting more complex shapes or prototype models.
ROUTER
12

• CNC plasma cutters are very similar to CNC routers in
size and setup.
• However plasma cutters don’t require as much of a
powerful set up because as opposed to dragging around
a spinning tool in material they fly above the table with a
plasma torch.
• Plasma cutters are made for cutting 2 dimensional profile
shapes into sheet metal.
PLASMA CUTTER
13

• CNC laser cutters follow the same principle as the
plasma cutter, except they use a powerful laser to
do the cutting.
• Laser cutters are often good for cutting wood,
plastic and metal; each will need a different
strength of laser suited for the material depending
on the hardness and thickness.
CNC LASER CUTTER
14

• A 3D printer uses a similar set up as a CNC router or
laser cutter, but unlike those machines it does additive
machine as opposed to subtractive machining.
• Instead of starting with a solid piece of material and
removing bits of that material to end up with the
desired part, the 3D printer starts with a blank canvas
and builds a part up layer-by-layer.
• The 3D printer does this either by using an extruder
that pushes a material (typically plastic) out from a tiny
nozzle, or by using a laser that quickly solidifies a
powder or liquid.
3D PRINTER
15

• A pick and place machine again uses a similar set
up as a CNC router or laser cutter.
• This time instead of a tool used for cutting a
material, there are multiple small nozzles that pick
up electrical components using a vacuum. The
machine then moves to a desired location and
places that electrical component down on the
printed circuit board (hence the name pick and
place).
• Pick and place machines move very quickly and are
used to place the many hundreds or even
thousands of electrical components that make
up devices such as computer motherboards,
phones / tablets, and pretty much everything
else that has a printed circuit board.
PICK AND PLACE MACHINE
16

• 5 axis CNC machines add two rotary axes to the
typical three axis setup.
• The rotary axes allow much more complex
machining to produce parts that would be
impractical/impossible to do on a “normal” CNC
router or mill
5AXIS CNC MACHINE
17

18
 2 Axis if all the cutting takes place in the same plane. In this case, the cutter
does not have any capability of movement in the Z (vertical) plane. In general
the X and Y axes can interpolate together simultaneously to create angled lines
and circular arcs.
 2.5 Axis if all the cutting takes place entirely in planes parallel to the principal
plane but not necessarily at the same height or depth. In this case, the cutter
can move in the Z (vertical) plane to change levels, but not simultaneously with
the X,Y movements.
 An exception might be that the cutter can interpolate helically, that is, do a circle
in X,Y while moving simultaneously in Z to form a helix (for example in thread
milling).
 A subset of the above is that the machine can interpolate any 2 axes together
simultaneously, but not 3.
 This does make a limited number of 3D objects possible, by cutting in the XZ or
YZ planes, for example, but is much more limited than full 3 axis interpolation.
DIFFERENT AXIS SYSTEM

19
 3 Axis if your cutting requires simultaneous controlled movement of the X,Y,Z
axes, which most free-form surfaces require.
 4 axis if it includes the above plus 1 rotary axis movement. There are two
possibilities: 4 axis simultaneous interpolation (also known as true 4th axis). Or
just 4th axis positioning, where the 4th axis can reposition the part between 3 axis
operations, but does not actually move during the machining.
 5 axis if it includes the above plus 2 rotary axis movements. Besides true 5 axis
machining (5 axes moving simultaneously while machining), you also often
have 3 plus 2 or 3 axis machining + 2 separate axes positioning only, as well as in
rarer cases 4 plus 1 or continuous 4 axis machining + a single 5th axis positioning
only

G-CODES
G00 Rapid positioning
G01 Linear
interpolation
G02 Arc - Clockwise
G03 Arc - Counter
Clockwise
G04 Dwell
G09 Exact stop check
G10 Programmable
data input
G17 XY plane selection
G18 ZX plane selection
G19 YZ plane selection
G20 Programming in
Inches
G21 Programming in Millimeters (mm)
G28 Return to home Return to machine zero on the
current work offset.
G30 Return to second home
G31 Skip function Used for probes and tool length
measurement systems
G40 Tool radius compensation off
G41 Tool radius compensation left
G42 Tool radius compensation right
G49 Tool length offset compensation
cancel
G53 Machine Coordinate System
G54-59 Work Coordinate Systems
G90 Absolute positioning
G91 Relative positioning
G92 Define current position
G94 Feed rate per minute
G97 Spindle constant speed
20

M00 Compulsory
stop
M01 Optional stop
M02 End of
program
M03 Spindle on Clockwise
rotation
M04 Spindle on Counter-
clockwise
rotation
M05 Spindle stop
M06 Automatic
tool change
(ATC)
M07 Coolant on Mist
M08 Coolant on Flood
M09 Coolant off
M10 Pallet clamp
M11 Pallet clamp off
M13 Spindle on Clockwise
rotation and
coolant on
flood
M19 Spindle
orientation
M48 Feedrate
override
allowed
M49 Feedrate
override not
allowed
M52 Unload last tool
from spindle
M98 Subprogram
call
M99 Subprogram
M-
CODES
21

ADVANTAGES
1. High Repeatability and Precision e.g. Aircraft parts.
2. Volume of production is very high .
3. Complex contours/surfaces need to be machined.
4. Flexibility in job change, automatic tool settings, less scrap.
5. More safe, higher productivity, better quality.
6. Less paper work, faster prototype production, reduction in lead times.
22

DISADVANTAGES
1. Costly setup, skilled operators
2. Computers, programming knowledge required
3. Maintenance is difficult
23

24
1) Book: CAD/CAM: Computer-Aided Design and Manufacturing, by
Mikel P. Grover
2) https://wiki.mcneel.com/rhino/cncbasics
3) WIKIPEDIA
REFERENCES

Types of cnc machines

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