cnc machines - lecture-notes.tiu.edu.iq
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CNC MachinesPREPARED BY SARASERWER
Outline
History
Important terms in Manufacturing
NC Machines
DNC Machines
Working principle of CNC Machine
Classification of CNC Machines
Types of CNC Machine
History
In 1775, John Wilkinson- cannon boring machine (lathe).
In 1881, Eli Whitney- milling machine.
In 1947, Mr. John Parsons began experimenting for using 3-axis
curvature data to control the machine tool motion for the
production for aircraft components.
In 1949, parsons- first NC machine.
In 1955, after refinements NC became available in industry
Today, modern machinery are CNC milling machines and lathes.
Important terms in Manufacturing
ISO International Organization for standardization
CAD Computer Aided Drawing
CAM Computer Aided Manufacturing
NC Numerical control
CNC Computer Numerical Control
CIM Computer Integrated Manufacturing
RP Rapid Prototyping
CAP Computer Aided planning
DNC Direct Numerical Control
CAI Computer Assisted Industry
EDM Engineering Data management
NC Machines
Numerical Control (NC) is an approach of automatically operating
a manufacturing machine that is focused on a code Letters,
numbers, and characters of a specific nature.
Elements of NC machines Program that include instruction that could be entered to the machine by using punch tape
MCU (Machine Control Unit) is electronic and control hardware, it is used for implement the
instruction that received from the input device . And also the monitoring result and correcting the
code take place if there is any error occur in the system.
Machine Tools mechanical structure that implement machining process.
Program MCU Machine Tool
DNC Machines
DNC: is a manufacturing system in which a large number of machines are
controlled by computer through direct connection.
Figure : Explanation of the DNC Machine
CNC Machine
The CNC machine can be described as a computer-controlled
machine and the operation is carried out by feeding the program
on it.
CAD stands for Computer-aided designCAM stands for Computer-aided manufacturing
Working principle of CNC Machine
The part program is loaded into the CNC's MCU.
All the data process takes place in the MCU and it prepares all the motion commands
according to the program prepared and sends them to the driving system.
The drive system works as the motion commands are sent by MCU. The drive mechanism
manages the machine tool 's motion and velocity.
The feedback system records the machine tool's measurement of position and velocity
and sends a feedback signal to the MCU.
The feedback signals are compared with the reference signals in the MCU, and if there
are errors, it corrects them and sends new signals to the machine tool for the correct
operation to happen.
The display unit is used to see all the commands, programs, and other important data.
Figure :Block Diagram of the working principles for CNC Machines
Difference Between NC and CNC Machines
Types of CNC Machine
CNC laser cutting machine
CNC Lathe Machine
CNC Milling Machine
CNC router Machine
CNC Plasma Cutting Machine
5- axis machine
3-D Printer
Pick and Place Machine
CNC Lathe
CNC lathe machines can create a variety of cuts, shapes and details
required on a rotating work part. Computer Numerical Control lathe
machine is programmed to produce intricate cuts on hard materialsand create quality products in less consumption of time with high rate.
Figure: CNC Lathe
Product that produced by CNC Lathe machine
1) Bowls
2) Baseballs bats
3) Camshafts
4) Cue sticks
5) Crankshafts
6) Gun Barrels
7) Musical Instruments
8) Dining Room Table
9) Chair legs
Figure: application of the CNC lathe
CNC Milling
Milling is the process of using revolving cutters to remove material from an object advancing in a certaindirection at an angle with the axis of the tool.
• CNC milling machines are computer controlled. A computer is used to move and operate the spindlecutting head. The computer program moves the head with absolute precision. These machines have atable in which raw materials are clamped down by the operators to cut.
The material that is suitable for milling operation
Aluminum
Brass
Magnesium
Nickel
Steel
Thermoset plastics
Titanium
Zinc
Figure: Horizontal CNC milling
Machine
Figure :Vertical CNC Milling Machine
CNC Drilling Cutting Machines
Drilling is the cutting process in which the workpiece does not move,
making the cutter to move for generating the hole.
Figure: CNC Drilling Machine
CNC Router
CNC Routers uses Three axis rotating to remove material from stock. It works
similarly as other CNC machines like lathe or Milling do. The main difference is, it
does all the carpenter work manually like such as door carvings, interior and exterior
decorations, wood panels, signboards, wooden frames, moldings, musical instruments,
The material that can be used during the routing operation;
1. Wood
2. Plastics
3. Composites
4. Aluminum
5. Steel
6. Glass
7. foam CNC Router
CNC Laser
This device uses laser for cutting purposes and this machine also is
computer based machine like other type of CNC machine.
The material that can be use for laser cutting operation;
1. Aluminum
2. Carbon steel
3. Stainless steel
Figure : CNC Laser MachineVideo on working operation of
laser Machine
CNC Plasma cutting Machine
CNC Plasma cutting machine uses high temperature plasma torch to cut all kind of
metal material such as (stainless steel, low carbon steel , brass, copper ,gold,
silver..etc)
Figure :CNC PLASMA MACHINE
3D Printing
3D printing: it is one of the additive manufacturing process , it is used for producing
of the three dimensional product from a CAD model.
Many different Types of materials use for 3D Printing process;
ABS PLASTIC
Polyamide(nylon)
Stereolithography materials(epoxy resin
Silver
Steel
Photopolymers
polycarbonate Figure :3D printing Machine
CNC File Format
STEP(Standard for Exchange of Product model data)
IGES (Initial Graphics Exchange Specification)
DXF (Drawing Interchange Format)
STL (Surface Tesselation Language)
CAD AND CAM CAD stands computer aided drawing
CAM stands computer aided manufacturing takes a CAD drawing file in and use
information to create G code
Flow Diagram for CAD CAM software Figure : Example of CAM program for CNC Lathe
Circle Diagram for CAD AND CAM SOFTWARE that used for supporting CNC machine
CAD ,CAM SOFTWARS
CNC MACHINE
AutoCAD
CATIA
Rhino
Fusion 360
Solidworks
Free CAD
Application of CNC Machines
The main application of CNC macnines like(cutting
,drilling,milling,welding,Boring,Bending,spinning,pinning,Sewing,Routing)
In comparison to a traditional machine-like lathe, milling machine, the main
applications of the CNC machine is to remove metal at a faster rate.
This is also used in fabrication industries.
The machine can be used in mass production.
This machine is used for automatic removal of metal from the workpiece .
Working Video of a CNC Machine
Next Lecture
Conventional and CNC (lathe)
Conventional and CNC (Milling
Difference between manually and computer based machine
The structure of the part program
Rrferences
https://www.gestiondecompras.com/en/products/machining/millin
g
Machining and CNC Technology 4th Edition by Michael Fitzpatrick