Control of Manufacturing Processesdspace.mit.edu/bitstream/handle/1721.1/56569/2-830... · Date Lecture Topic Assignment 6 Tue, 24 Feb Describing Variation: Probability and Random

Control of Manufacturing Control of Manufacturing ProcessesProcesses

Subject 2.830 6303

Subject 2.830 Spring 2004Spring 2004Lecture #1Lecture #1

“Introduction”“Introduction”

February 3, 2004February 3, 2004

2/3/04 2.830 /6303 Lecture #1 © David E. Hardt 2

BackgroundBackground

•• PrePre--requisitesrequisites•• Your Background and InterestsYour Background and Interests•• Relevant ExperienceRelevant Experience•• Course ScheduleCourse Schedule


ExpectationsExpectations

•• Assignments ~ WeeklyAssignments ~ Weekly•• 1 Lab in class1 Lab in class•• 2 Quizzes in Class2 Quizzes in Class•• Textbook (for middle half of course)Textbook (for middle half of course)

– Montgomery, D.C., Introduction to Statistical Quality Control, 4th Ed. Wiley, 2001


Syllabus DetailsSyllabus Details

Instructors:• MIT : David Hardt

– (Office Hours by appointment)• Singapore: Dr. Lu Wen Feng NTU

• Prof. Chen I-Ming, NTU

• Class Support: Lisa Falco


Syllabus DetailsSyllabus Details

• Prerequisites: Either or both :– 2.010 Classical control systems– 15.075 Probability and Statistics

• Text Required: Montgomery, D.C., Introduction to Statistical Quality Control, 4th Ed. Wiley, 2001

• Grading: Problem sets 50%; Quizzes 35%Class Participation 15%

• Assignments: All except Optimization Project are to be Individual efforts

• Course URL: (Certificate Required)http://stellar.mit.edu/S/SMA/sp04/sma.6303/index.html


Part I Part I -- Origins of VariationsOrigins of VariationsLecture

# Date Lecture Topic Assignment

1 Tue, 03 Feb8:00-9:30AM Introduction #1 Process Overview

2 Thurs , 05Feb Process Modeling for Control Ź

3 Tues, 10Feb Sources of Variation #1 Due, #2 Lab and Data

Reduction

4 Thur, 12 Feb Laboratory Raw Data in Spreadsheetdue ASAP after lab

5 Thur, 19 Feb The Nature of Variation: LabInterpretation

# 2 Due,# 3Process Modeling


Part II Statistical DescriptionPart II Statistical DescriptionLecture


6 Tue, 24 Feb Describing Variation:Probability and Random Variables Ź

7 Thur, 26Feb

Shewhart Model of Manufacturingand ŅChartingÓ

# 3 Due,#4 Normal Statistics

8 Tue,02 Mar SPC Charting and Process CapabilityŹ

9 Thur, 04Mar SPC Methods and Process Capability # 4 Due, #5 SPC and

Cpk

10 Tue, 9 Mar Advanced SPC: Moving AverageApproaches Ź

11 Thur, 11Mar

Introduction to Empirical ProcessModeling and Optimization

# 5 Due

Ź Tue, 16 Mar Quiz #1 (Covers through Lecture10) Ź


Part III Process OptimizationPart III Process OptimizationLecture


12 Thur, 18Mar

Designed Experiments: the 2-kproblem

# 6 DOE and ProcessModels

13 Tue,30 Mar Model Building and Testing Ź

14 Thur, 01Apr

Analysis of Variance and ModelTesting

# 6 Due #7 ANOVAmodel tests

15 Tue,06 Apr Optimization using Empirical Models Ź

16 Thur, 08Apr Fractional Factorial Models # 7 Due #8 Process

Optimization Project


Part IV Feedback ControlPart IV Feedback ControlLecture


17 Tue, 13 AprFeedback Control for Process

Improvement: Introduction: BasicServo Problem Ź

18 Thur, 15Apr Basic Loop Analysis # 8 Due #9 Machine

Feedback control

19 Thur, 22Apr Position Servo Analysis # 9 Due #10 Cycle to

Cycle Control

20 Tue,27 Apr Cycle to Cycle Control: The Basics Ź

21 Thur 29 Apr Discrete System Closed-LoopDynamics

# 10 Due,# 11 Summary Project

22 Tue, 04May

Variation Reduction in Cycle to CycleControl

Ź

23 Thur, 06May Application of Cycle to Cycle Control Ź# 11 Due


Manufacturing Process ControlManufacturing Process Control•• Process GoalsProcess Goals

–– CostCost–– QualityQuality–– RateRate–– FlexibilityFlexibility


Processes and SystemsProcesses and Systems

•• Successive OperationsSuccessive Operations–– Serial Quality DependenceSerial Quality Dependence

•• Parallel OperationsParallel Operations–– Dependence at AssemblyDependence at Assembly

Μ1 Μ2 Μ3

Μ1

Μ2Μ3


2.830 Focus2.830 Focus

•• Unit OperationsUnit Operations•• (1) Maximizing Quality(1) Maximizing Quality

–– Conformance to SpecificationsConformance to Specifications•• (2) Improving Throughput(2) Improving Throughput•• (3) Improving Flexibility(3) Improving Flexibility

•• (4) Reducing Cost(4) Reducing Cost


2.830 Perspectives2.830 Perspectives

•• Process OperationProcess Operation–– Make the best with what we haveMake the best with what we have

•• Statistical Process ControlStatistical Process Control

•• Process DesignProcess Design–– Explore limitsExplore limits

•• Process OptimizationProcess Optimization

–– ReRe--design to change what we havedesign to change what we have•• Feedback ControlFeedback Control


2.830 Methods2.830 Methods

•• Physical Origins of Physical Origins of Process VariationsProcess Variations

•• Manufacturing as a Manufacturing as a Random ProcessRandom Process

•• Empirical Process Empirical Process OptimizationOptimization

•• Feedback ControlFeedback Control of Random of Random ProcessesProcesses


The General Case: The General Case: “It’s always feedback control”“It’s always feedback control”

Controller Process

e-Ts

PartSpec.

Part

measurement delay

In-ProcessEvery Cycle

sampled inspection

Tprocess ~hour ~days ~months

customer returns

warranty recall


Typical Process Control ProblemsTypical Process Control Problems

•• Extrusions for an Airframe don’t fitExtrusions for an Airframe don’t fit--up at up at assemblyassembly

•• Electrical Connector bodies don’t fit Electrical Connector bodies don’t fit securelysecurely

•• Circuit Board connector terminals don’t Circuit Board connector terminals don’t line up with solder padsline up with solder pads

•• Semiconductor resist coating is nonSemiconductor resist coating is non--uniformuniform



•• Airframe skin needs trimming and Airframe skin needs trimming and bending to fit framebending to fit frame

•• Web thickness of a machined panel is Web thickness of a machined panel is nonnon--uniformuniform

•• Plastic throttle bodies for fuel injection Plastic throttle bodies for fuel injection are out of roundare out of round

•• Submarine hull welds need constant Submarine hull welds need constant rework in productionrework in production



•• Minimum feature size on a semiconductor Minimum feature size on a semiconductor chip has too much variabilitychip has too much variability

•• DNA Diagnostic Chip has uneven flow DNA Diagnostic Chip has uneven flow channelschannels

•• Toys never fit when assembled at home!Toys never fit when assembled at home!•• Next generation high density electrical Next generation high density electrical

connector cannot be made reliablyconnector cannot be made reliably

Other Related Problems:Other Related Problems:Cost, Rate and Flexibility:Cost, Rate and Flexibility:

•• 100% inspection with high scrap rates100% inspection with high scrap rates–– low throughputlow throughput–– high costshigh costs

•• 100% Inspection with frequent rework 100% Inspection with frequent rework –– low throughputlow throughput–– high costshigh costs

•• High Variability at changeoverHigh Variability at changeover–– Reluctance to changeover Reluctance to changeover –– low flexibilitylow flexibility


Manufacturing ProcessesManufacturing Processes

•• How are they defined?How are they defined?•• How to they do their thing?How to they do their thing?•• How can they be categorized?How can they be categorized?

•• Why don’t they always get it right?Why don’t they always get it right?


The Process ComponentsThe Process Components

Operator PartWorkpiece Material

Equipment

• Etch bath• Injection Molder • Lathe• Draw Press• ...

•Coated Silicon •Plastic Pellets• Bar stock• Sheet Metal• ...

• Semiconductor•Connector Body•Shaft•Hood• ...


Process DefinitionProcess Definition

A Manufacturing Process is a Change in the Workpiece Material

• A change in geometry

• A change in constitutive properties


What Causes the Change?What Causes the Change?

•• A Directed Energy Exchange with the A Directed Energy Exchange with the EquipmentEquipment

Equipment MaterialE(t ) Geometry &

Properties

E(t ) →

mechanicalelectricalthermalchemical

⎧

⎨ ⎪ ⎪

⎩ ⎪ ⎪

⎫

⎬ ⎪ ⎪

⎭ ⎪ ⎪


Modes of Geometry Change?Modes of Geometry Change?

•• RemovalRemoval of Materialof Material•• Plastic Plastic DeformationDeformation of Materialof Material•• AdditionAddition of Materialof Material•• FormationFormation of Material from a Gas or of Material from a Gas or

LiquidLiquid

•• Any others???Any others???


What Controls the Geometry What Controls the Geometry Change?Change?

–– location of max. shear stress in turninglocation of max. shear stress in turning

Location and Intensity of Energy ExchangeLocation and Intensity of Energy Exchange•• ExamplesExamples:


What Controls the Geometry Change?What Controls the Geometry Change?


–– heat transfer at the mold surface in injection moldingheat transfer at the mold surface in injection molding


Control of Geometry Change?Control of Geometry Change?

– location of laser beam in laser cutting




–– reaction rate reaction rate -- time product on substrate surface in LPCVDtime product on substrate surface in LPCVD

Location and Intensity of Energy ExchangeLocation and Intensity of Energy Exchange



Location and Intensity of Energy ExchangeLocation and Intensity of Energy Exchange•• displacement field in sheet forming :


Two Extremes of Interactions Two Extremes of Interactions

•• Concentrated, “Lumped” Energy PortConcentrated, “Lumped” Energy Port–– Small Area Wrt Total Part GeometrySmall Area Wrt Total Part Geometry

•• Distributed Energy PortDistributed Energy Port–– Area ~ Total Part GeometryArea ~ Total Part Geometry

Documents

Control of Manufacturing Processesdspace.mit.edu/bitstream/handle/1721.1/56569/2-830... · Date Lecture Topic Assignment 6 Tue, 24 Feb Describing Variation: Probability and Random