Me 300 Manufacturing Process Laboratory

7/31/2019 Me 300 Manufacturing Process Laboratory

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BE 300 MANUFACTURINGPROCESS LABORATORY

REFERENCE


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General Instruction

Students should pass safety test

Students should be familiar with equipments

and machines before to use themWe have a long tradition to make agyroscope.

We will measure the length and diameter ofthe screws as well as the diameter of washersto simulate a statistical process control


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Rules

Students must submit the laboratoryform to Mr. James Altop before they

start the work at the laboratory.The collected Laboratory forms will bethe basis of your grade for attendance

and achievements. Any safety violationwill heavily affect your grade.


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ME 300L MANUFACTURING PROCESS LABATTENDANCE SHEET

This sheet will be a basis for your final grade. Please turn in this sheet every time youvisit the laboratory, otherwise it will be recorded as absences. Please submit to Mr.James Altop before you leave.

Date____________________Your Name__________________________Signature________________Time in ___________________ Time out ____________________Team members name that are working with you today. Identify who are missing today.

Describe the task you planned to do today

What did you achieve today? Are there any remarks and suggestions?

Official Notes (signed by Mr. James altop)


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Observed safety rules? Poor Moderate GoodBehaved well? Followed instructions? Poor

Moderate GoodCleaned and reorganized after work? Poormoderate GoodWorked efficiently? Poor moderate GoodWork quality Poor moderate GoodAny remarks?


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How to Write the Report

Students must write the laboratoryreports in a professional way. Please

think that the reader of your report is anon-engineering person, maybe yourboss in marketing department, or a

lawyer investigating an accident.


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Due Date of the Laboratory Reports

The statistical process control report isdue by July 26.

The report for the manufacturing of thegyroscope is due by August 2.


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Remarks on Notebook

The lab notebook starts with the introductionof elementary statistics. I will teach you later.

Your laboratory reports must contain graphs,tables, and theoretical backgrounds.

The first lab on the notebook is the measuring

Brinell hardness before and after rollingprocess and heat treatments. I believe you dida Brinell test at GE 206 Lab. I will skip thistest.


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Remarks on Notebook, Continued

The second lab is about quality and processcontrol/measurements. We will do this lab.

Your report must be a fully written report(not a laboratory sheet, which is nothing buta raw data). Please write the followings;

introduction, scope of the work, theoreticalbackground, your results (not raw data, butprocessed data; attach raw data as areference), analysis, conclusion, suggestions,

references.


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The next one is about Hardenability(Jominy test). We will skip this. During

class, I will cover this.The mechanical properties test , Ibelieve, was done at GE 206 Lab.

We will do the Gyroscope project.

No welding project for the summersemester


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The forging and sheet metal processwill be skipped. I recommend you a

field trip to see the process.CNC machine; we will not do this as theproject. But I believe you will learn to

use it before you graduate.


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Safety

1. Report any injury to Mr. James Altop or to Dr.Jung

2. When in doubt about the use of machines,equipment or instrumentation, check with Mr.Altop. Many accidents are caused byimproper use

3. Know where your first aid equipment islocated.

4. Know where your fire extinguishers arelocated and how to use them.


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Safety; cont

5. Never work alone in the laboratory.

6. Emergency number is 911.

7. Wear your safety glasses or eye shieldswhen you are producing metal chips,using machine tools or hand tools, or arein the vicinity of such a hazard.

8. Report all broken, damaged, or missingtools.


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Safety; cont

12.Do not wear neckties or other loosefitting clothes that could become

entangled in a running machine.13.Always clean your machine and working

area when you are finished.

14.If a classmate is in danger by improperuse of equipment, be a buddy, and

provide assistance.


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Statistics

Dealing With Uncertainty


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Objectives

Describe the difference between a sample and apopulation

Learn to use descriptive statistics (data sorting,central tendency, etc.)

Learn how to prepare and interpret histograms

State what is meant by normal distribution and

standard normal distribution.

Use Z-tables to compute probability.


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Statistics

There are lies, d#$& lies,and then theresstatistics.

Mark Twain


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Statistics is...

a standard method for...

- collecting, organizing, summarizing,

presenting, and analyzing data- drawing conclusions

- making decisions based upon the

analyses of these data.used extensively by engineers (e.g.,quality control)


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Populations and Samples

Population - complete set of all of thepossible instances of a particular object

e.g., the entire class

Sample - subset of the population

e.g., a team

We use samples to draw conclusionsabout the parent population.


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Why use samples?

The population may be large

all people on earth, all stars in the sky.

The population may be dangerous to observe automobile wrecks, explosions, etc.

The population may be difficult to measure

subatomic particles.Measurement may destroy sample

bolt strength


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Measurements

Measurements are frequently made inengineering and science. Thesemeasurements are made to quantify

characteristics of the system being studied.If the measurement can be reduced to asingle value that we are 100% certain is thetrue value, we do not need statistical methods

For most measurements, we are not 100%certain; thus, statistical techniques need to beused.


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Team Exercise: Sample Bias

To three significant figures, estimatethe average age of the class based

upon your team.

When would a team not be a

representative sample of the class?


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Measures of Central Tendency

If you wish to describe a population (or asample) with a single number, what do youuse?

Mean - the arithmetic average

Mode - most likely (most common) value.

Median -middle of the data set.


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What is the Mean?

The mean is the sum of all data valuesdivided by the number of values.


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Sample Mean

Where:

is the sample mean

xiare the data points

n is the sample size

n

i

ix

nx

1

1

x


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Population Mean

Where:

is the population mean

xiare the data points

Nis thetotal number of observations in thepopulation

N

i

ix

N1

1


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Mode continued

Example of a grade distribution withmean C, mode B

0

5

10

15

20

25

F D C B A


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What Is the Range?

Range - the difference between thelowest and highest values in the set.

Example, driving time to Portland is 2hours +/- 15 minutes. Therefore...

Minimum = 105 min

Maximum = 135 minutesRange = 30 minutes


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Standard Deviation

Gives a unique and unbiasedestimate of the scatter in the data.


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Standard Deviation

Population

Sample

2

1

)(1

N

i

ixN

2

1

)()1(

1xx

ns

n

i

i

Deviation

Variance = 2

Variance = s2


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The Subtle DifferenceBetween and s

N versus n-1

n-1 is needed to get a better estimate of

the population from the sample s.

Note: for large n, the difference is trivial.


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Team Exercise

In your teams bag of M&M candies,count

the number of candies for each color the total number of candies in the bag

When you are done counting, have arepresentative from your team enteryour data on the board

Using Excel or calculators, enter thedata gathered by the entire classMore


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Team Exercise (cont)

For each color, and the total number ofcandies, determine the following:

maximum mode

minimum median

range standard deviationmean variance

I di id l E i


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Individual Exercise:Histograms

Flip a coin EXACTLY ten times. Count thenumber of heads YOU get.

Report your result to the instructor who will

post all the results on the boardOpen Excel

Using the data from the entire class, create

bar graphs showing the number ofclassmates who get one head, two heads,three heads, etc.


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The Normal Distribution

The normal distribution is sometimescalled the Gauss curve.

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1

2

1RF

x

e

mean

x

RF

RelativeFrequency


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Standard Normal Distribution

Define:

Then

/ xz

2RF

2

2

1z

e

0.0

0.1

0.2

0.3

0.4

0.5

-4.0 -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0

Area = 1.00

z


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The area under the probability density

function equals 1 meaning that the probabilitythat x has a value between the lower andupper limit is certain.

Therefore, the shaded area under the curve

defines a probability of 0.6827 that x has avalue between 2 and + 2

Mathematically, this probability is defined as

2

2

)(]22[ dxxfxP


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Summary Table

SampleStatistics

PopulationParameters

Mean

Variance S2 2

Standarddeviation

S=(S2)1/2 =( 2)1/2

x


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Confidence IntervalsConfidence intervals are calculated usingsample data and define a probable range fora population parameter at a given confidencelevel.

For example, a 95% confidence interval willdefine and upper and lower limit for aparameter and implies that we are 95%certain based on the sample used that the

parameter is between these limits. We willonly consider confidence intervals for thepopulation mean,


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Large Sample Method

When the sample is large enough we canassume that sx

2 = 2 ; thus, three commonconfidence intervals are:

99%

95%

90%

n

sx x58.2

n

s

xx

96.1

n

sx x64.1


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Small Sample Method

For small samples, the sample variancehas not stabilized and the assumption,

sx2

= 2

cannot be made. Theconfidence interval now is defined as:

n

stx x


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Using Confidence Intervals

When conducting experiments, it is best toreplicate (repeat) tests or measurements ofvalues on a test part. The sequence of values

that represent the characteristic of interestare used to make a decision regarding thepopulation that the sequence of values (thesample) are supposed to represent.

The average value of the characteristic is themost natural way to condense these samplevalues and it is hoped that this average isclose to the true average for the population.


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The confidence interval is used toprovide a measure of how close. The

smaller the confidence interval, thecloser the sample mean is to thepopulation mean.

Another way to use the confidenceinterval is to make comparisons amongmultiple samples.



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Let' say you have two samples consisting ofmeasurements of the same characteristicssuch as a material's hardness. One sample

was taken from a batch of material that washeat treated at one temperature and thesecond sample from a batch heat treated at adifferent temperature

The average sample hardness for thesebatches differ. Does this mean thetemperature difference has affectedhardness? Not necessarily.



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A confidence interval for these averagevalues should be computed. If the

lower bound of one confidence intervalis greater than the upper bound of thesecond confidence interval, we can bemore confident that the temperaturehas affected hardness.



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STATISTICAL QUALITYCONTROL

See Quality Control Chapter


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Using Z Tables

Question: Find the area between z= -1.0and z= 2.0

From table, for z = 1.0, area = 0.3413 By symmetry, for z = -1.0, area = 0.3413

From table, for z= 2.0, area = 0.4772

Total area = 0.3413 + 0.4772 = 0.8185

Tails area = 1.0 - 0.8185 = 0.1815

Quick and Dirty Estimates of


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Quick and Dirty Estimates of and

@ (lowest + 4*mode + highest)/6

For a standard normal curve, 99.7% of

the area is contained within 3 fromthe mean.

Define highest = 3

Define lowest = 3 Therefore, @ (highest - lowest)/6

Example:


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Example:Drive time to Everette

Lowest = 1 h

Most likely = 2 h

Highest = 4 h (including a flat tire, etc.) = (1+4*2+4)/6 = 2.16 (2 h 12 min)

= (4 - 1)/6= 0.5 h

This technique (Delphi) was used toplan the moon flights.


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Review

Central tendency mean

mode

median

Scatter range

variance

standard deviation

Normal Distribution


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Data Analysis in Excel

Analysis of Uncertainty


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Learning Objectives

Learn to use statistical Excel functions:

average, median, min, max, stdev, var, varp,

standardize, normdist, norminv, normsinv


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General Excel Behavior

- Analyzes the range of cells youspecify

- Skips blank cells


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Mean

Excel

=AVERAGE(cellrange)=AVERAGE(B72:B81)

Example:

n

i

ix

n

x

1

1

N

i

ix

N 1

1

Sample Population


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Mode

Value that occurs most often indiscretized data

Excel Example:=MODE(cellrange) =MODE(B2:B81)

If tie, reports first value in list


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Example - Exam Grades

Data set: grades.xls

78 students, 1 did not take exam

Verify the following:

Mean is 79.41

Mode is 79 - occurs 6 times

Median is 79.5

median close to mean suggests no major outliersRemember, student who did not take exam is notincluded in data

More
http://grades.xls/http://grades.xls/


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Example Cont.

Verify

max is 99

min is 60Range is 99-60 = 39

Population variance is 60.7

Population std. dev. is 7.79


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Team Exercise - 15 min

Collect ages (in months) of teammembers and members of teams

around you (at least 15 values)Enter as a column in Excel

Compute mean, mode, median, max,

min, range, samplevariance and std.dev. using Excel commands


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Z-transform

Excel

=STANDARDIZE(x,mean,stddev)

Example:

=STANDARDIZE(85,75,10) gives 1.0

/ xz

Standard Normal Cumulative


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Standard Normal CumulativeDistribution

Excel Example:

=NORMSDIST(z) =NORMSDIST(1.0)

=0.8413

0.0

0.1

0.2

0.3

0.4

0.5

-4.0 -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0

area from minus

infinity to z

NOT

0 to z, like Z-table


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Exam Grade Histogram

0

5

10

15

20

25

50 55 60 65 70 75 80 85 90 95 100

Score Bins

Frequency

Actual Scores

Normal Approx


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Excel Example

Normal distribution with =5, =0.2

Find area from 4.8 to 5.4

Solution 1:=STANDARDIZE(4.8,5,0.2) Gives -1

=STANDARDIZE(5.4,5,0.2) Gives 2

=NORMSDIST(2)-NORMSDIST(-1) = 0.8186

Solution 2:=NORMDIST(5.4,5,0.2,TRUE)-

NORMDIST(4.8,5,0.2,TRUE) = 0.8186


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Inverse Problem:


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Example 2

A batch of bolts have length =5.00 mm, =0.20mm. The bolt length is specified as 5.00 mm tolerance. What is the value of the tolerance

such that 99% of the bolts are encompassed?Solution:

=NORMINV(0.995,5,0.2) = 5.52 mm

=NORMINV(0.005,5,0.2) = 4.48 mmTolerance = 5.52 - 5.00 = 0.52 mm

Note: It is symmetrical; therefore 0.5% on either side


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Think-Pair-Share

In the next 1 minute, as an individual

list threespecific things that you dont understandabout todays topic

Now take 2 minutesto merge your list with the person sitting next to youAND add 1 new item to the list

In the next 5 minutes

share the results with the other half of your team,delete questions that you can answer for eachother, AND prioritize the remaining questions yourlist

Me 300 Manufacturing Process Laboratory

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