MFE2101 - Lecutre 1 - Prefix

MFE2101

Engineering Metrology

1

MFE 2101 – ENGINEERING METROLOGY


Month Week Date Lecture

October

1 01/10/2015 Lecture 1 Prefix: Dimensioning & Tolerancing

2 08/10/2015 Lecture 2 Introduction to Apparatus and Measurement

3 15/10/2015 Lecture 3 Measurement of Length & Internal Diameters

4 22/10/2015 Lecture 4 Measurement using Optics

5 29/10/2015 Lecture 11 Uncertainty in Measurements

November

6 05/11/2015 Lecture 5 Straightness, Flatness and Perpendicularity

7 12/11/2015 Lecture 6 Angle Measurement

8 19/11/2015 Lecture 7 Taper Measurement & Surface Texture

9 26/11/2015 Lecture 8 Radius Measurement & Roundness

December

10 03/12/2015 Lecture 9 Thread Measurement

11 10/12/2015 Lecture 10 Gear Metrology & CMM

12 17/12/2015 Tutorial 1

Assignment Deadline

13 24/12/2015 CHRISTMAS RECESS

January 14 31/12/2015

15 07/01/2016 Tutorial 2

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• Notes / Tutorial Sheets / Lab Sheets will be

uploaded on VLE

• Books: 1. Fundamentals of Dimensional Metrology by C. Dotson

(ISBN: 978-1-4180-2062-0)

2. Handbook of Dimensional Measurement by Curtis,

Farago

(ISBN: 978-0-8311-0204-3)


• What is Metrology?

• Why Metrology?

• Manufacturing Process Variation

• The Product Development Cycle and Metrology

• Part Dimensioning and Tolerancing

• Conclusion

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• METROLOGY is the science of measurement, and

measurement is the language of science. It is the

language we use to communicate about size, quantity,

position, condition and time.

Grammar Composition Language

Metrology Techniques

Experience Metrology

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Mass Length Time

Egyptian Jewelers' Balance

(circa. 2000BC)

Egyptian Royal Cubit

(circa. 3000BC)

Greek Sun Dial

(circa. 200BC)


• Time Measurement:

– Stopwatch on Mobile Phones

• Length Measurement:

– Rulers on your desks

• Weight Measurement:

– Weighing scales in kitchens at home

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In real world

applications an

Engineer is often

confronted with

problems which have to

be investigated.

One of the main

resources in the

engineering toolbox is

the science of

Metrology.

Engineer

Metrology

Tools

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• Pen Production

Bottom Part Top Part

Problem: Parts NOT Fitting


• Parts and problem report are sent to the

engineer responsible for the product.

• The engineer has then to investigate the

problem or problems with these parts.

• The engineer will issue a measurement report

which identifies a number of dimensions which

might be causing the problem.

• Following the receipt of the report, the engineer

will evaluate the findings and propose a solution

to the problem.

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Raw Material 2

Raw Material 1

Raw Material 3

Raw Material n

.

. Customer

Product

Requirements

and Wishes

Product 2

Product 1

Product 3

Product n

.

.

Value Adding Manufacturing

Processes •Milling

•Turning

•Injection Molding

•Assembly


Plastic Injection Molding Machine CNC Lathe Machine

VIDEOS

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Overall

Length Dim C8


Need

Conceptual Design

Embodiment Design

Detailed Design

Production

Feedback

Modified phases of the design

process according to French

Metrology

Metrology

Metrology

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• Concept Development:

– Physical Prototype Stage


• Parts might need to be used for:

– Customer Evaluation

– Initial Testing

• Before parts can be used they have to be

measured to make sure that they meet the

engineering specifications

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• Detailed Product Design


• Parts might need to be used for:

– Initial Product Runs

– Final Testing

– Shipping to Customer

– Process Qualification

• Before parts can be used they have to be

measured to make sure that they meet the

engineering specifications

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• Production Environment


• Parts have to be:

– Under Control

• dimensions have to be monitored to ensure there

are no shifts in the manufacturing process

– Fit for use

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What are you going to

measure?

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• The Engineering Drawing or Model defines

the Specification for the Product


Nominal

Dimension Tolerance

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Plastic Injection Molding Machine CNC Lathe Machine


Tighter Tolerances

Hig

her

Co

sts

(mm)

(€)

[Simmons & Maguire, 2004]

Units o

f C

ost

Tolerance (mm)

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Shaft

Bearing


Shaft

Bearing

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Clearance Size-to-Size Interference

3 types of parts are found in production:

Type 2 Type 1 Type 3


…After taking a closer look at your drawings

Shaft Bearing

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Tolerance Check (Worst Case Scenario)

1. Nominal Condition: (Nominal Bearing) 50.0 - (Nominal Shaft) 50.0 = 0mm

2. Maximum Clearance: (Maximum Bearing) 50.5 - (Minimum Shaft) 49.5 = 1mm

3. Maximum Interference: (MinimumBearing) 49.5 - (Maximum Shaft) 50.5 = -1mm


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Tolerance Check (Worst Case Scenario)

1. Nominal Condition: (Nominal Bearing) 49.75 - (Nominal Shaft) 50.25 = 0.5mm

2. Maximum Clearance: (Maximum Bearing) 50.5 - (Minimum Shaft) 49.5 = 1mm

3. Maximum Interference: (Minimum Bearing) 50 - (Maximum Shaft) 50 = 0mm


Hook

Hinge

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y = 75±0.5 - 60±0.5

y = 15±1mm

ymin = 14mm

ymax = 16mm

x = 50±0.5 - 19±0.5 – 15±0.5

x = 16±1.5mm

xmin = 14.5mm

xmax = 17.5mm

Possible Interference of 1.5 mm between X min and Y max


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y = 14±0.5mm

ymin = 13.5mm

ymax = 14.5mm

x = 16±0.5mm

xmin = 15.5mm

xmax = 16.5mm

Minimum Clearance of 1 mm between X min and Y max

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• During this lecture we have seen:

– What is Metrology

– Why Metrology

– Manufacturing Process Variation

– The Product Development Cycle and Metrology

– Part Dimensioning and Tolerancing

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• Dr Ing. Paul Refalo

– Room 003

– [email protected]

Date post:	06-Dec-2015
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MFE2101 - Lecutre 1 - Prefix

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