Lo #5 manufacturing technology (jan 2016)

Manufacturing Technology 1
Manufacturing TechnologyManufacturing Technology
LO #5 Advanced Manufacturing Technology
Reference pages in the e-textbook (P. 964 ~ 986)

2Manufacturing Technology
Automation FundamentalsAutomation Fundamentals
Automation can be defined as the technology by which a process or
procedure is performed without human assistance. Humans may be
present as observers or even participants, but the process itself
operates under its own self-direction. Automation is implemented by
means of a control system that executes a program of instructions. To
automate a process, power is required to operate the control system
and to drive the process itself.
Three Components of an Automated SystemThree Components of an Automated System
 Power
 Program of instructions
 Control system to carry out the instruction

Program of instructions
The program of instructions is executed by a control system, the
third basic component of an automated system. Two types of
control system can be distinguished: closed loop and open loop.
A closed-loop system, also known as a feedback control system, is
one in which the process variable of interest (output of the process)
is compared with the corresponding process parameter (input to the
process), and any difference between them is used to drive the
output value into agreement with the input.

Program of instructions
Open-loop system executes the program of instructions
without a feedback loop. No measurement of the output
variable is made, so there is no comparison between output
and input in an open loop system.

Types of Automation
Fixed Automation
In fixed automation, the processing or assembly steps and their
sequence are fixed by the equipment configuration.
(Ex. Mechanized assembly line)
Programmable Automation
As its name suggests, the equipment in programmable automation is designed
with the capability to change the program of instructions to allow production of
different parts or products.
(Ex. NC Machine Tools)
Flexible Automation
Suitability for batch production is mentioned as one of the features of
programmable automation.
(Ex. Production line of car manufacturing / assembly line)

Types of Automation

Hardware for Automation
1. Sensors ;
A sensor is a device that converts a physical stimulus or variable of
interest (e.g., temperature, force, pressure, or other characteristic of the
process) into a more convenient physical form (e.g., electrical voltage)
for the purpose of measuring the variable.
2. Actuator ;
Actuator is a device that converts a control signal into a physical
action, which usually refers to a change in a process input parameter.
The action is typically mechanical, such as a change in position of a
worktable or rotational speed of a motor.

3. Interface Devices ;
Interface devices allow the process to be connected to the computer
controller and vice versa. Sensor signals from the manufacturing
process are fed into the computer, and command signals are sent to
actuators that operate the process.
Ex) Analog-to-Digital Converter (ADC), Digital-to-analog converter
4. Process Controllers ;
Most process control systems use some type of digital computer as the
controller. Whether control involves continuous or discrete parameters
and variables, or a combination of continuous and discrete, a digital
computer can be connected to process to communicate and interact
with it using the interface devices.
Ex) PLC (Programmable Logic Controller)

Major components of a programmable logic controller

10
CAD/CAM / NC /CNC
Manufacturing Technology

11
CAD / CAM / NC / CNCCAD / CAM / NC / CNC
 Computer-aided design (CAD) uses a computer and software to
make accurate drawings of parts and products.
 CAD can show what the product will look like, how it should be
made, how it will work, and what materials it will be made of.
 CAD research began in the 1960.s in the automotive and
aerospace industries (General Motors, McDonnell Douglas)
 In 1963, Ivan Sutherland developed the first sketch pad for
manipulating computer graphics. As computers have become
faster and more powerful, CAD software packages have
become commonplace in the modern industrial workplace.
 Boeing’s 777 airplane was designed entirely on computer,
without the construction of an initial prototype
CAD

12
 AutoCAD
 ProEngineer
 Ideas
 SolidWorks
 Unigraphics
 Others
CAD Packages

13
 Computers are also used to operate and control many machines and
processes used in manufacturing.
 CAD drawings may sometimes be directly input into a CAM system.
 In the 1950.s MIT demonstrated the numerical control of a machine using
a computer language called Automatically Programmed Tool (APT).
 Numerically Controlled (NC) machinery has been developed to perform a
diverse array of operations, such as milling and turning.
CAM

14
 SolidWorks/CAM
 Mastercam
 PowerMill
 ProEngineer
 CATIA
 Feature CAM
 Others
CAM Software

15
CAD / CAM - Advantages
 Setup time reduction
 Lead time reduction
 Accuracy and repeatability
 Contouring of complex shapes
 Simplified tooling and work holding
 Consistent cutting time
 General productivity increase

16
Drawing (CAD)
NC programing(CAM)
Send to machine tools(DNC)
CPU
Operating Servo parts
Manufacturing
CNC Machine Tools Data Processing
CPU
CPU

17
 The modem CNC system, but not the old NC system, uses an
internal micro processor (i.e., a computer).
 This computer contains memory registers storing a variety of
routines that are capable of manipulating logical functions.
 That means the part programmer or the machine operator can
change the program on the control itself (at the machine), with
instantaneous results.
 This flexibility is the greatest advantage of the CNC systems and
probably the key element that contributed to such a wide use of the
technology in modem manufacturing.
 In contrast to the NC system, the CNC system is synonymous with
the term 'softwired'.
The CNC System

18
 Direct numerical control (DNC), also known as distributed numerical
control (also DNC), is a common manufacturing term for networking
CNC machine tools.
 On some CNC machine controllers, the available memory is too
small to contain the machining program (for example machining
complex surfaces), so in this case the program is stored in a
separate computer and sent directly to the machine, one block at a
time.
 If the computer is connected to a number of machines it can
distribute programs to different machines as required.
The DNC System

19
Main computer
NC data
< DNC >
< CNC >
Computer Computer Computer Computer Computer

20
 Highly automated machine tool capable of performing multiple
machining operations under CNC control in one setup with
minimal human attention.
 Typical operations are milling, turning and drilling
 Three, four, or five axes
 Other features:
 Automatic tool changing‑
 Pallet shuttles
 Automatic workpart positioning
Machining Centers & Turning Centers

21
Highly automated machine tool that can perform turning, milling, and
drilling operations on a workpart.
General configuration of a turning center
Can position a cylindrical workpart at a specified angle so a rotating
cutting tool (e.g., milling cutter) can machine features into outside
surface of part.
A conventional turning center cannot stop workpart at a defined
angular position and does not possess rotating tool spindles
Mill – Turn Centers

22
Operation of a mill turn center:‑
(a)example part with turned, milled, and drilled surfaces; and
(b) sequence of operations on a mill turn center:‑
(1) turn second diameter,
(2) mill flat with part in programmed angular position,
(3) drill hole with part in same programmed position, and
(4) cutoff
Mill – Turn Centers

23
SpindleSpindle
BedBed
Z (Depends on
machine)
Machine Coordinate SystemsMachine Coordinate Systems

24
Address /
Code
Functions
N Sequence number
G Preparatory
1)One shot (Blockwise) G function : G04, G28, G92
2)Modal G function : G00, G01, ….
X_Y_Z
I_J_K_R_
Coordinate Word ( mm)
F Feed-rate Function (mm/min)
S Spindle Function
1 Word = Address + Data1 Word = Address + Data
NC Programming - AddressNC Programming - Address

25
G- Code Functions
T Tool Function
M Miscellaneous Function
H, D Tool compensation number designation
(Height, Diameter)
NC Programming - AddressNC Programming - Address

26
Code Functions
G92 Zero point setting
EX) G92 X____Y____Z____
G54 ~ 59 Zero point shifting ON
Ex) G54 : Zero point shifting 1 ON
G90
G91
Absolute programming
Incremental programming
G00 Positioning or Rapid Traverse
(= Linear interpolation with maximum speed)
Ex) G00 x value y value z value
G01 Linear interpolation with programmed speed
Ex) G01 x value y value z value F value (feed rate)
G-Code : Preparatory FunctionG-Code : Preparatory Function

27
G-Code : ExampleG-Code : Example

28
(Absolute programming)
(Incremental programming)
G-Code : Preparatory Function G90 & G91G-Code : Preparatory Function G90 & G91

Lo #5 manufacturing technology (jan 2016)

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