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


Automation FundamentalsAutomation FundamentalsProgram 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.


Automation FundamentalsAutomation FundamentalsProgram 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.


Automation FundamentalsAutomation FundamentalsTypes of Automation

Fixed AutomationIn 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 AutomationSuitability for batch production is mentioned as one of the features of programmable automation.(Ex. Production line of car manufacturing / assembly line)


Automation FundamentalsAutomation FundamentalsTypes of Automation


Automation FundamentalsAutomation FundamentalsHardware 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

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CAD/CAM / NC /CNC

Manufacturing Technology

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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


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AutoCAD ProEngineer Ideas SolidWorks Unigraphics Others

CAD Packages



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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



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SolidWorks/CAM

Mastercam

PowerMill

ProEngineer

CATIA

Feature CAM

Others

CAM Software



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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



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Drawing (CAD)

NC programing(CAM)

Send to machine tools(DNC)

CPU

Operating Servo parts

Manufacturing

CNC Machine Tools Data Processing



CPU


CPU


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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



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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



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Main computerNC data

< DNC >

< CNC >Computer Computer Computer Computer Computer


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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



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Highly automated machine tool that can perform turning, milling, and drilling operations on a workpart.General configuration of a turning centerCan 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



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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


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SpindleSpindle

BedBed

Z (Depends on machine)

Machine Coordinate SystemsMachine Coordinate Systems



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Address / Code

Functions

N Sequence number

G Preparatory 1)One shot (Blockwise) G function : G04, G28, G922)Modal G function : G00, G01, ….

X_Y_ZI_J_K_R_

Coordinate Word ( mm)

F Feed-rate Function (mm/min)

S Spindle Function

1 Word = Address + Data 1 Word = Address + Data NC Programming - AddressNC Programming - Address



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G- Code Functions

T Tool Function

M Miscellaneous Function

H, D Tool compensation number designation (Height, Diameter)


NC Programming - AddressNC Programming - Address


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Code Functions

G92 Zero point setting EX) G92 X____Y____Z____

G54 ~ 59 Zero point shifting ON Ex) G54 : Zero point shifting 1 ON

G90G91

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 speedEx) G01 x value y value z value F value (feed rate)


G-Code : Preparatory FunctionG-Code : Preparatory Function


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G-Code : ExampleG-Code : Example



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(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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