1

ISE 484/ME 473 Flexible and Lean Manufacturing Systems

Course Outline

R. Van Til Industrial & Systems Engineering Dept.

Oakland University

Copyright 2012. Robert P. Van Til. All rights reserved.

2

Focus of Course

•  Technologies which increase flexibility in the modern manufacturing environment will be considered.

Ø  Either in small batch systems or in large mass production systems.

Ø  The emphasis will be on:   What are the technologies?

  How do you use them?

3

Focus of Course

•  For example, a Computer-Aided Manufacturing (CAM) system. Ø  We will study:

  What is a CAM system.

  How to operate a CAM system.

  How to use CAM as a bridge from CAD to CNC.

Ø  We will not study:   How a CAM system makes all those pretty pictures.

•  That is, linear transformation theory, splines, and a whole lot of other mathematical techniques that take place inside a CAM program.

4

Course Topics

•  Overview of the manufacturing environment. •  Manufacturing safety procedures. •  Performance of production systems. •  Lean manufacturing. •  Group Technology (GT). •  Robotic systems. •  Material transport & storage systems. •  Programmable Logic Controllers (PLC). •  Vision systems. •  Sensors. •  Geometric dimensioning & tolerancing. •  Computer Numerically Controlled (CNC) systems. •  Computer-Aided Manufacturing (CAM).

5

Manufacturing Overview

•  Broad overview of the modern manufacturing environment.

Ø  Classification of manufacturing systems.

Ø  Manufacturing’s essential functions.

Ø  Production planning.

Ø  Manufacturing plant layout.

6

•  Parts flow through a production system to produced finished products. Ø  We will consider the behavior of flow lines.

  Many different products are produced in flow lines. •  Cars, airplanes, consumer electronics and cookies

  Number of products produced (throughput) and distribution of parts in the flow line (Work-In-Progress or WIP) effected by:

•  Machines with different processing times.

•  Machine failures.

•  Accumulator locations and capacities.

Performance of Production Systems

7

Lean Manufacturing

•  Lean manufacturing is based on the Toyota Production System.

Ø  Major focus of lean manufacturing is on the reduction of waste throughout the system.

  Several lean manufacturing tools will be presented.

Ø  Lean techniques are also being applied in many nonmanufacturing industries.   Examples: healthcare, service and logistics.

8

Group Technology

•  Group technology (GT) involves the classification of different parts that have similar:

Ø  Design attributes.

Ø  Manufacturing attributes.

•  Hence, when it’s time to design or manufacture a new part, use the GT classification code to find how similar parts were designed or manufactured.

•  GT is used to answer that age-old question:

Why reinvent the wheel?

9

Robotic Systems

•  Robots are programmable devices which are primarily used to:

Ø  Transport material.   Example: Load/unload machine tools

Ø  Process parts.   Examples: Spot welding or spray painting

10

Example - Industrial Robots

11

•  Material transport systems.

Ø  Conveyors

Ø  Fork Lifts

Ø  Automated Guided Vehicles (AGV)

•  Material storage systems.

Ø  Warehouse

Ø  Accumulating conveyors

Ø  Automated Storage/Retrieval Systems (AS/RS)

Material Transport & Storage

12

•  Material transport and storage are nonvalue-added processes.

Ø  Hence, it is very important to optimize them.   One goal of lean manufacturing is to minimize the

amount of material transportation and storage.

Material Transport & Storage

13

•  A PLC is a microprocessor device used to control manufacturing systems.

Ø  Often used to control sequential processes.   Examples. A conveyor system or a multi-robot spot

welding station.

Ø  PLC programming methods:

  Ladder logic diagrams (older method).

  Sequential function charts, flow charts (newer methods).

Programmable Logic Controller (PLC)

14

I1

I2

O1 I4

I3 I5

O1

O2

O3

Example - PLC Ladder Logic Diagram

15

Initial

Load_part

Press_dwn

Press_up

Unload_part

I1_Run

O1_Prox

O2_LS_Dwn

O3_LS_Up

NOT O1_Prox

Example - PLC Sequential Function Chart

N O6_Press_ram

N O4_Conv1_Mtr

N O5_Conv2_Mtr

N O7_Robot

16

Vision Systems

•  A vision system collects data for use by the manufacturing system.

Ø Usually illuminate objects with either visual light or laser light.

Ø Vision systems are used for:   Feature identification.

•  Example: Tell a robot where a car’s windshield frame is located so it can place the windshield.

  Inspection.

•  Example: Did the machine tool cut a correct size hole in the specified location?

17

Example - Vision Systems

18

Sensors

•  A sensor measures some physical quantity and converts it to an electrical or visual signal.

Ø  Electrical signals often send to computers.

Ø  Visual signals often send to humans.

Ø  Example: Sensor that measures your car’s speed.   Electrical: sent to car’s cruise controller in order to

control the speed.

  Visual: a gage (i.e., speedometer) displays the speed to the driver.

19

Sensors

•  In manufacturing, sensors often used by computers and humans to monitor and control various systems.

Ø  Types of sensors used in manufacturing:

  Thermal

  Mechanical

  Electrical

  Optical

  Chemical

  Acoustic

20

•  An international standard used for placing dimensions and tolerances on engineering drawings.

Ø  Standard implies that everyone uses the same:

  Definitions

  Terminology

  Symbols

Geometric Dimensioning & Tolerancing

21

•  A computer-based control system used to control various manufacturing systems.

Ø  Usually used to control machine tools such as lathes, mills, machining centers and grinders.

Ø  Uses a low-level programming language.   Commands called G-codes.

Computer Numerical Control (CNC)

22

Example - CNC Machine Tools

23

N5 G90 G20 N10 M06 T2

N15 M03 S1200 N20 G00 X1.00 Y2.20 Z-3.75

N25 G01 X-0.50 Y1.25 F5.0 N30 G01 X0.25 Y-0.55 F3.5

N35 G00 Z0.00 N40 G00 X0.00 Y0.00 Z0.00 N45 M05

N50 M30

Example - G-Code Program

24

•  A CAM system converts a CAD diagram of a part into a CNC G-code program to produce the part. Ø  A high-level programming language.

Ø  CAM is a 2 step process: 1.  Using the CAD drawing, guide a simulated CNC

machine tool through the desired machining process.

»  Called a tool path diagram.

2.  Convert the tool path information into a G-code program.

»  Called post-processing.

Computer-Aided Manufacturing (CAM)

25

Example - Tool Path Diagram