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

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Machining and CNC Technology 4th Edition by Michael Fitzpatrick