MATERIAL SCIENCE LECTURE

Inroduction to Engineering materials from Aravind Balaji

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IES PREVIOUS YEAR QUESTION PAPER

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mechanical objective paper2

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ENGINEERING SCIENCE QUESTION PAPER

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MECHANICAL ENGINEERING QUESTION BANK

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FULL FORMS

Full FormsA.M. — Ante meridian
P.M. — Post meridian
B. A. — Bachelor of Arts
M. A. — Master of Arts
 B. Sc. — Bachelor of Science
M. Sc. — Master of Science
B. Sc. Ag. — Bachelor of Science in Agriculture
M. Sc. Ag. — Master of Science in Agriculture
 M. B. B. S. — Bachelor of Medicine and Bachelor of Surgery
 M. D. — Doctor of Medicine
M. S. — Master of Surgery
Ph. D. / D. Phil. — Doctor of Philosophy (Arts & Science)
D. Litt./Lit. — Doctor of Literature / Doctor of Letters
D. Sc. — Doctor of Science
B. Com. — Bachelor of Commerce
M. Com. — Master of Commerce
Dr. — Doctor
B. P. — Blood Pressure
Mr. — Mister
Mrs. — Mistress
M.S. — miss (used for female married & unmarried)
 Miss — used before unmarried girls)
M. P. — Member of Parliament
M. L. A. — Member of Legislative Assembly
M. L. C. — Member of Legislative Council
 P. M. — Prime Minister
C. M. — Chief Minister
 C-in-C — Commander-In-Chief
L. D. C. — Lower Division Clerk
U. D. C. — Upper Division Clerk
 Lt. Gov. — Lieutenant Governor
D. M. — District Magistrate
V. I. P. — Very Important Person
I. T. O. — Income Tax Officer
C. I. D. — Criminal Investigation Department
 C/o — Care of
S/o — Son of
C. B. I. — Central Bureau of Investigation
G. P. O. — General Post Office
H. Q. — Head Quarters
E. O. E. — Errors and Omissions Excepted
Kg. — Kilogram
Kw. — Kilowatts
 Gm. — Gram
Km. — Kilometer
Ltd. — Limited
M. P. H. — Miles Per Hour
 KM. P. H. — Kilometre Per Hour
 P. T. O. — Please Turn Over
P. W. D. — Public Works Department
C. P. W. D. — Central Public Works Department
 U. S. A. — United States of America
U. K. — United Kingdom (England)
 U. P. — Uttar Pradesh
 M. P. — Madhya Pradesh
 H. P. — Himachal Pradesh
U. N. O. — United Nations Organization
 W. H. O. — World Health Organization
B. B. C. — British Broadcasting Corporation
B. C. — Before Christ
A. C. — Air Conditioned
 I. G. — Inspector General (of Police)  D. I. G. — Deputy Inspector General (of Police)  S. S. P. — Senior Superintendent of Police  D. S. P. — Deputy Superintendent of Police  S. D. M. — Sub-Divisional Magistrate  S. M. — Station Master  A. S. M. — Assistant Station Master  V. C. — Vice-Chancellor  A. G. — Accountant General  C. R. — Confidential Report  I. A. S. — Indian Administrative Service  I. P. S. — Indian Police Service  I. F. S. — Indian Foreign Service or Indian Forest Service  I. R. S. — Indian Revenue Service  P. C. S. — Provincial Civil Service  M. E. S. — Military Engineering Service  Full Form Of Some technical Words VIRUS - Vital Information Resource UnderSeized. 3G -3rd Generation. GSM - Global System for Mobile Communication. CDMA - Code Divison Multiple Access. UMTS - Universal MobileTelecommunication System. SIM - Subscriber Identity Module . AVI = Audio Video Interleave RTS = Real Time Streaming SIS = Symbian OS Installer File AMR = Adaptive Multi-Rate Codec JAD = Java Application Descriptor JAR = Java Archive JAD = Java Application Descriptor 3GPP = 3rd Generation Partnership Project 3GP = 3rd Generation Project MP3 = MPEG player lll MP4 = MPEG-4 video file AAC = Advanced Audio Coding GIF= Graphic InterchangeableFormat JPEG = Joint Photographic Expert Group JPEG = Joint Photographic Expert Group BMP = Bitmap SWF = Shock Wave Flash WMV = Windows Media Video WMA = Windows Media Audio WAV = Waveform Audio PNG = Portable Network Graphics DOC =Document (MicrosoftCorporation) PDF = Portable Document Format M3G = Mobile 3D Graphics M4A = MPEG-4 Audio File NTH = Nokia Theme (series 40) THM = Themes (Sony Ericsson) MMF = Synthetic Music Mobile Application File NRT = Nokia Ringtone XMF = Extensible Music File WBMP = Wireless Bitmap Image DVX = DivX Video HTML = Hyper Text Markup Language WML = Wireless Markup Language CD -Compact Disk. DVD - Digital Versatile Disk. CRT - Cathode Ray Tube. DAT - Digital Audio Tape. DOS - Disk Operating System. GUI -Graphical User Interface. HTTP - Hyper Text Transfer Protocol. IP - Internet Protocol. ISP - Internet Service Provi

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master alloys

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FLEXIBLE ASSEMBLY LINE

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DRILLING MACHINE

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Assembly-Line Balancing

Assembly-Line Balancing:   An effective  tool for improving Productivity

1. What is assembly-line balancing?

l  to a workstation within an assembly line in order to meet the required production rate and to achieve a minimum amount of idle time.

l  Line balancing is the procedure in which tasks along Assigning each task the assembly line are assigned to work station so each has approximately same amount of work.

2.  Unbalance Line and Its effect

l  High work load in some stages (Overburden)

l  Maximizes wastes (over-processing, inventory, waiting, rework, transportation, motion)

l  High variation in output

l  Restrict one piece flow

l  Maximizes Idle time

l  Poor efficiency

3.Balanced Line and its effect

l  Promotes one piece flow

l  Avoids excessive work load in some stages (overburden)

l  Minimizes wastes (over-processing, inventory, waiting, rework, transportation, motion)

l  Reduces variation

l  Increased Efficiency

l  Minimizes Idle time

4.  How Can Assembly-Line Balancing   Help Organization ?

l  Increased efficiency

l  Increased productivity

l  Potential increase in profits and decrease in costs

 5. Steps in Balancing an Assembly Line

1. List the sequential relationships among tasks and then draw a precedence diagram.
2. Calculate the required workstation cycle time.
3. Calculate the theoretical minimum number of workstations.
4. Choose a primary rule that will determine how tasks are to be assigned to workstations.
5.  Beginning with the first workstation, assign each task, one at a time, until the sum of the task times is equal to the workstation cycle time or until no other tasks can be assigned due to sequence or time restrictions.
6.  Repeat step 5 for the remaining workstations until all the tasks have been assigned to a workstation.
7. Evaluate the efficiency of the line balance.
8. Rebalance if necessary.

Example of Assembly-Line Balancing

Problem: The Model Z Bicycle is assembled in an assembly line. Four hundred and twenty  bicycles are required each day. Production time per day is 420 minutes.

            Find the balance that minimizes the number of workstations, that stays within the workstation cycle time limitation, and that complies with task precedent constraints. 

Example of Assembly-Line Balancing Cont.
1. Building the Model Z Bicycle: Assembly Steps and Times

Task	Task Time (in seconds)	Task Description	Tasks that must precede
A	50	Connect the front tire to the bicycle frame.	—
B	16	Insert the handle bar.	A
C	14	Tighten handle bar with two screws and nuts.	B
D	55	Connect the rear tire to the bicycle frame.	—
E	20	Position chain mechanism to the frame.	D
F	17	Attach right hand brake to handle bar.	C
G	17	Attach left hand brake to handle bar.	C
H	17	Attach right side pedal.	E
I	17	Attach left side pedal.	E
J	13	Position chain onto chain mechanism.	F,G,H,I
K	14	Attach seat post.	J
	250

STEP 1. List the sequential relationships among tasks and then draw a precedence diagram

STEP 2.  . Calculate the required workstation cycle time

Convert minutes to seconds because task times are in seconds.

CYCLE TIME  = (PRODUCTION TIME PER DAY) /(OUTPUT PER DAY)

                        = (60 sec. X  420 min.)  / ( 420 bicycles)  

                         = 25,200 / 420   =  60  sec.

STEP 3. Calculate the theoretical minimum number of workstations.

NUMBER OF WORK STATIONS  = ( SUM OF TOTAL TASK TIMES) / (CYCLE TIME)

=  250sec’s  /  60 sec’s

                                                        =   3.97  = 4  (rounded)

Task	Number of Following Tasks
A	6
B or D	5
C or E	4
F, G, H, or I	2
J	1
K	0

STEP 4.Choose a primary rule that will determine how tasks are to be assigned to workstations

l  For this example, our primary rule is to prioritize tasks based on the largest number of following tasks.

l  If there is a tie, our secondary rule is to prioritize tasks in the order of the longest task time.

l  In general, select rules that prioritize tasks according to the largest number of followers or based on length of time.

STEP 5. Beginning with the first workstation, assign each  task, one at a time, until the sum of the task times is equal to the workstation   cycle time or until no other tasks can be assigned due to sequence or time restrictions.

STEP 6. Repeat step 5 for the remaining workstations until all the tasks have been assigned to a workstation

STEP 7.Evaluate the efficiency of the line balance.

EFFICIENCY   =   (SUM OF ALL TASK TIMES))/(ACTUAL NO OF WORKSTATIONS)X(CYCLE TIME)

=  (250)  / (5) X (60)  

=  0.83  OR  83 %

STEPS  5& 6. Balance made according to the Largest-Number-of-Following Tasks Rule

Stations	Task	Task Time (in seconds)	Number of Following Tasks	Remaining Unassigned Time	Feasible Remaining Tasks	Task with Most Followers	Task with Longest Operating Time
Station 1	A	50	6	10 idle	None
Station 2	D	55	5	5 idle	None
Station 3	B E C	16 20 14	5 4 4	44 24 10 idle	C, E C, F,G, H, I,J None	C, E C	E
Station 4	F G H	17 17 17	2 2 2	43 26 9 idle	G, H, I H, I, J None	G, H, I H, I	G, H, or I H or I
Station 5	I J K	17 13 14	2 1 0	43 30 16 idle	J K None

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