Chapter 1 - Methods, Standards, and Work Design: Introduction !Elements of Standards of Living Defn.: the degree of wealth and material comfort available to a person or community. Food, Cloths, Education, Medical Insurance, Security. !Productivity relationship with standards of living - If productivity increase, standard of living increase. - Increasing productivity companies way to success. (Productivity i, Profit i) - Productivity improvement / enhancement refers to increase of output over working hour

constant. !Productivity VS. Production Production - the action of making / manufacturing. Productivity - Special measure of efficiency, defined as relationship between output by a given work system during a given period of time and the quantity of resources consumed to create the output. !!!to increase productivity: - increase output and reduce input. - Both increase, but output increase at higher rate. - Both decrease, but input decrease at higher rate. !Fundamental Tools for Improving Productivity • WSAD (Study)

- Design / redesign the best methods. - Select / reselect processes, tools, etc. - Methods Engineering, a.k.a: Operations analysis, WD, corporate re-engineering. !

• WSAD (Measurement) - Time study, determine time for job. - Standards are results of time study. (used to implement wages scheme) !

Work system analysis and design Analysing, designing, creating, and selecting the best manufacturing methods, processes, tools, equipments, and skills to manufacture a product based on the working drawings that have been developed by product engineers. !Work Design As part of developing / maintaining the new method, the principles of WD must be used to the task and workstation ergonomically to the human operator. !The overall procedure Defining the problem, breaking the job into operations, analysing each operation to determine the most economical procedure for the quantity involved, applying proper time values. !

AWM

Productivity = outputinput

Objectives of WSAD Mainly, to increase productivity, and lower unit cost; allowing more quality goods and services to be produced for more people. - Minimize time required for tasks. - Continuous improvement to quality and reliability. - Conserve resources. (Consider cost and power available) - Maximize safety, health, and well-being of employees. - Produce with high concern to environment. - Follow management program, resulting in job interest and satisfaction. !Influence of Methods, Standards, and Work Design (MSWD)

!WSAD and Time Study

!Standards are the end results of time study / work measurement. This technique establishes a time standard allowed to perform a given task, based on measurement of the prescribed method. !Method Systematic Steps 1. Select Project new product, plan, etc. 2. Get and Present Data obtain production requirements, procure engineering data and cost. 3. Analyze Data use why, where, what, who, when, how + 9 Approaches. 4. Develop Ideal Method W&M process charts, eliminate, combine, simplify, etc. 5. Present and Install Method use decision-making tools, overcome resistance, implement. 6. Develop a Job Analysis job analysis and description. 7. Establish Time Standards stopwatch time study, work sampling, standard data, etc. 8. Follow Up verify savings, assure correct installation, repeat.

S-GP-A-DM-PI-DJA-ETS-F !!

Sales Manager Cost is largely determined by manufacturing methods.

Controller Time standards are the bases of standard cost.

Manufacturing Manager Standards provide the bases for measuring the performance of production departments.

Purchasing Agent Time is common denominator for comparing competitive equipment and supplies.

Industrial Relations Good labor relations are maintained with equitable standards and a safe work environment.

Chief Engineer Methods work design and processes strongly influence product design.

Maintenance Standards provide the bases for preventive maintenance.

Reliability and QC Standards enforce quality.

Production Control Scheduling is based on time standards.

Manufacturing Department MSWD provide how the work is to be done and how long it will take.

Minimum work content of product

Work content added due to

defects

Work content added due by ineffective

work design

Time added due to shortcoming of management,

poor planning, etc.

Time added due to shortcomings of worker, excessive allowance, etc.

Goals of methods Opportunities for saving through MSWD

Total time of operation when MSWD is not practised

AWM

Chapter 2 - Problem Solving Tools !Using: Select project, Get & present Data, Develop Ideal Method. !Job Selection - Economic considerations (most important), involves new / existing products, simply “bottleneck

operations”. - Technical considerations processing techniques, QC, product performance. - Human considerations highly repetitive jobs, work-related accidents, high-accident rat jobs,

continuous workers complaints. !Exploratory Tools • Pareto Analysis: items of interest are identified and measured on a common scale, then ordered

in descending order (from highest to lowest) “y-axis cumulative frequency”. !• Fish Diagram: a.k.a cause and effect. ! ! !!!!• Gantt Chart: Shows the anticipated completion time for various project activities. Bar plot

against time on Horizontal axis. !• PERT Charting: Program Evaluation and Review Technique. Referred to the critical path

method (Critical path is the path where duration and time allowed are equal, in which if any delay in the critical activities, the whole project will be delayed). !

• Worksite / Job Analysis: identifies problems within a particular area, department, worksite. Before collecting data; analyst walks through the area and observe the workers, tasks, workplace, and work environment. Identify and administrative factors affecting behaviour / performance.

!!Operation Process Chart Shows chronological sequence of all operations, inspections, time allowances, and materials used. (from arrival of raw materials to packaging). The chart shows the entrance of all components and subassemblies to main assemblies. Using the following notations: !!

.xx” (seconds) D.W (day work) !Inspection Operation Junction No Junction Alternative Path Rework

AWM

Cause

Head (Effect) main complaint

Sub-cause

Flow Process Chart Contains more details than OPC. But it is applied for each component of an assembly. It is valuable for recording non production hidden costs, such as distance travelled, delays, temporary storages.

!!Flow Diagram is the pictorial plan of the FPC, helps visualising the real map. !Worker and Machine Chart (W&M) Used to study, analyze, improve one workstation at a time. The chart shows the exact time relationship between working cycle (operator) and operation cycle (machine). Illustrates the practise of machine coupling. !Gang Process Chart An adaptation of worker and machine chart. A worker and machine process chart helps determine the most economical number of machines one operate, but the gang process chart shows the exact relationship between the idle and operating cycles of the machine and the idle and operating times per cycle of the workers who service that machine. !Quantitative Tools, Worker and Machine Relationships Synchronous Servicing Ideal case, but because n* is not an integer, we have two cases, n1<n*, and n2>n*:

! , l (total loading and unloading),m (machine running time),n* (ideal number of machines)

For n1 < n*:

! $ / unit

For n2 > n*:

! $ / unit

TEC (Total Expected Cost) !The production rate: ! • n , Tc (cycle time “time / unit”) note: Production rate is units / hour.

!

n* = l +ml +w

TECn1=l +m( ) K1 + n1K2( )

n1 ⋅ 60( )

TECn2=l +w( ) K1 + n1K2( )

60( )

RP =1TC

n1 < n* :RP =

60l +m

i n1, n2 > n* :RP =

60l +w

AWM

Random Servicing Completely random servicing situations are those cases in which it is not known when a facility

needs to be serviced or how long servicing takes. The binomial expansion gives the approximate:

! , n (total numbers of machines), m (number of machines down)

the hours lost can be calculated as; if m ≤ w (number of workers) then hours lost = 0 “zero”. But if m > w, we use the following equation: hr. lost = !

Proportion of machine time lost = (hr. lost) / (total working time) **total working time= n•(working hours), e.g: if n = 3, and 8hr./day, then total working time=24** !and the Total Expected Cost ! , and Production Rate ! or Rp(1-hr.%)

!Line Balancing - Precedence Chart. - Put up a table; RPW (Ranked Positional Weight), and Rank from highest RPW to lowest. - RPW = ∑ of Te of all units depending on the unit. - Work Stations: find the ideal Tc using Rp; Divide work in stations such that Tc is not exceeded. - Line Balancing Efficiency

! , TWC (Total Workstation Content “ ∑ of all w/s times ”)

** For manual; LBE (95-100%), but for automated (~85%) ** !!!!

P m of n( ) = n!m! n −m( )! p

m . qn−m

m −w( ) i Pm of n( )( ) i working hours " 8"( )

TEC = K1 + nK2

RRP =

1TC 1− hr.%( )

LBE = TWCn ⋅TC

×100%

AWM

Chapter 3 - Operations Analysis Objectives Question every detail:

• What - improves the method. • Why - Purpose of operation. (main question) • How - Design, materials, tools, tolerance, and processes. • Who - Operator and work design. • When - sequence of manufacture.

All these aim to eliminate, combine, rearrange operations. !Lean Principles (Thinking) TPS - Toyota Production System (7 mudas “wastes”)

Waiting & transportation wastes - elements to be examined and eliminated with flow process chart. Wastes of motion - culminating (reaching highest level of dev.) the principles of WD & motion eco. Wastes of overproduction & excess inventory - in & out movement of stock. Wastes in defective products - producing scrap / require rework. The 5S: Sort, Set in order, Shine, Standardize, Sustain. !The 9 Approaches of Operations Analysis 1. Operations Purpose Most important, 25% of operations being performed can be eliminated. !2. Product (part) Design To improve, look for reducing cost:

• Reduce number of parts by simplified design. • Reduce number of operations & travelling for assembly. • Utilize a better material, and using tolerance. • Design for manufacturing / assembly. !

3. Tolerance & Specification tolerance are related to quality. They are considered when reviewing the design. Designers may have a tendency to incorporate specification that are more rigid than necessary. Lack of knowledge of cost. Cost decrease as Tolerance increase. !

4. Material Finding less expensive and lighter and easier to process. Using materials more economically, salvage materials, supplies and tools, standardising materials, finding the best vender for (stock & price). !

5. Manufacturing Sequence & Process Rearranging operations, mechanising manual operations, utilising more efficient facilities, operating facilities more efficiently, manufacturing near net shape, consider use of robots. !

6. Setup and Tools Most prevalent mistake of planners and tool makers is to tie up money in fixtures that may show a large savings when in use, but are seldom “rarely” used. This is done by: - Reduce setup time (JIT), - Utilize full capacity of machines, - More efficient tools, and set the Ratio of setup to production run time to be low. Dividing parts to families of similar time interval, shape, process.

• Over production • Inappropriate processing (over processing) • Waiting

• Unnecessary transportation • Excess inventory • Unnecessary motion • Defective products

AWM

7. Material Handling All materials moved periodically from location to location. Ensure no early nor late arrival of materials for production. Ensure materials delivered to the correct place and having no damage and in the proper quantity. Consider storage (temporary / dormant). Very high percent of total cost of bringing a product to market related to MH (30-85%). Distance (small or large) should be examined (inspected). Reducing time spent by:

• Reduce time spent in picking up material. • Use mechanical and Automated tools. • Make better use of existing handling facilities. • Handle materials with high care. • Consider bar coding inventory control and other applications.

The MH institute developed 10 principles: 1. Planning, 2. Standardisation, 3. Work, 4. Ergonomics, 5. Unit load, 6. Space utilisation, 7. System, 8. Automation, 9. Environmental, 10. Life-Cycle. ** the less a material is handled, the better it is handled. ** !

8. Plant Layout Important element of an entire production system that embraces operations, MH, inventory control, scheduling, routing and dispatching. Poor layout can result in major costs (most are hidden). 2 Types: • Straight-Line layouts: machinery is located such that the flow from one operation to the next

is minimized. • Process (Functional) layout: grouping of similar facilities into departments or building. This is

good for appearance and promotes good housekeeping. !9. Work Design Includes manual work and the principles of motion economy, ergonomics

principles, working and environmental conditions,cognitive (mental action of acquiring info.) work with respect to informational input from displays, information processing, and interaction with computers, and workplace and systems safety. !

AWM

Chapter 10 - Time Study Time study is also know as Work Measurement !3 Methods: - Estimates, - Historical Records, - Work measurement procedures. Before study is conducted; • The operator should verify that he/she performs the correct method. • The operator should become familiar with all details of the operation. • The supervisor should check if the method follow standards as established. • Supervisor should check that there is no shortage during study. !Minimum equipments:

!Time study elements

* operator should be above average, shows interest, and be familiar with time study. The analyst should be few feet away from operator, so he doesn’t interfere with the operator, analyst should also avoid conversations with operator while conducting time study. !Number of Cycles in Time Study

!

Note: if C.I is not given, take it as 95%. ** as cycle time of the operation decreases, then number of cycles to be conducted increase ** !

!

• Stopwatch (decimal minute watch). • Pocket calculator.

• Time study board. • Time study form.

• Videotape cameras. • Time study software.

• Selecting the operator.* • Analyze job and break into elements.

• Record elapsed elemental values. • Performance rating (R) and allowance (%)

x = sample mean = ∑i=1

nxin

, n = no. of sample elements, t − distribution value (tα2, n−1

)

s = standard deviation = ∑i=1

nxi − x( )2

n −1, k = acceptable error (fraction of x) ,

Ν = t ⋅ sk ⋅ x

⎡⎣⎢

⎤⎦⎥

2

(number of cycles), α 2 =1− Degree of freedom (C.I)( )

2

E = He

Hc

×100% = Oc

Oe

×100%

Basic Variables Efficiency of Operator

OT - Observed Time R - Performance rating He - Hours Earned Hc - Clock hr. on job

NT - Normal time = OT x R / 100 Oe - Expected output Oc - Current Output

ST - Standard Time = NT ( 1 + allowance(%) )

AWM

Chapter 11 - Performance Rating and Allowance !Performance Rating

Standard Performance Rating (R)

!!Synthetic Rating !

!!Westinghouse System Includes: - Skill - Effort - Condition - Consistency ! x 100% , Machines have R = 100%. !!Objective Rating R = P x D, P: Pace rating factor, D: difficulty. !!!

Allowances Three Types

• Personal: (4.6 - 6.5 %) = generally 5%. • Fatigue

• Basic: 4% • Variable: 10 classes, (Total Variable Fatigue = ∑(10 classes))

• Special: • Unavoidable delay. • Avoidable delay. • Extra. • Policy; added by the company. !** good conditions means lower allowance, and bad conditions will offer higher allowances ** !!!

Speed Rate

d1 dm d2

Warm up To be measured End up

P = Ft → Fundamental timeOt → Observed time

R = 1 + ∑ Skill + Effort + Condition + Consistency( )⎡⎣ ⎤⎦

AWM

% Per. = StandardActual

, then take average from readings

d1 - distance of warm up, d2 - distance of end up.

Chapter 12 - Standard Data and Formula Sources: • Nomogram: intersection between lines and rules. • Standard recorded data. !• Formulas: Drilling

! To the left, if drilling is through-all, but to the right it is for hole of length (L). ! , l = lead.

! , ! , ! min.

!! Lathe

! !** remember that T is the OT, for machines NT = OT, but ST = NT(1+allowance (typ. 10%)). **

Fm = feed (in. / min.), f = feed (in. / rev), Sf = feet / min, d = diameter of drill

l = rtanθ

, L = l + t, θ = angle of drill2

Fm = f ⋅n = f ⋅Sf ⋅12π ⋅d

⎛⎝⎜

⎞⎠⎟=3.82 ⋅ f ⋅Sf

dT = L

Fm

AWM

Fm =3.82 ⋅ f ⋅Sf

d in. / min.( )

T = LFm, L = l + length of cut.

Chapter 13 - Predetermined Time Systems Methods-Time Measurement (MTM) MTM-1 Gives time values for the fundamental motions of reach, move, turn, grasp, position, disengage, and release. Each of the above motions are also categorised by distance, ease, or angle. Special unit is used in the tables, TMU, which 1 TMU = 0.036 sec. !

!

MTM-1: Reach - R(X)(Case)

Distance Moved (X in.)

Time (TMU)Hand in Motion

Case and DescpritionA B C or D E A B

≤ 0.5 2.0 2.0 2.0 2.0 1.6 1.6 A - Reach to object in fixed location, or to object in other hand or on which other hand rests. !!B - Reach to single object in location which may vary slightly from cycle to cycle. !!C - Reach to object jumbled with other objects in a group so that search and select occur. !!D - Reach to very small object or where accurate grasp is required. !!E - Reach to indefinite location to get hand in position for body balance or next motion or out of way.

1 2.5 2.5 3.6 2.4 2.3 2.3

2 4.0 4.0 5.9 3.8 3.5 2.7

3 5.3 5.3 7.3 5.3 4.5 3.6

4 6.1 6.4 8.4 6.8 4.9 4.3

5 6.5 7.8 9.4 7.4 5.3 5.0

6 7.0 8.6 10.1 8.0 5.7 5.7

7 7.4 9.3 10.8 8.7 6.1 6.5

8 7.9 10.1 11.5 9.3 6.5 7.2

9 8.3 10.8 12.2 9.9 6.9 7.9

10 8.7 11.5 12.9 10.5 7.3 8.6

12 9.6 12.9 14.2 11.8 8.1 10.1

14 10.5 14.4 15.6 13.0 8.9 11.5

16 11.4 15.8 17.0 14.2 9.7 12.9

18 12.3 17.2 18.4 15.5 10.5 14.4

20 13.1 18.6 19.8 16.7 11.3 15.8

22 14.0 20.1 21.2 18.0 12.1 17.3

24 14.9 21.5 22.5 19.2 12.9 18.8

26 15.8 22.9 23.9 20.4 13.7 20.2

28 16.7 24.4 25.3 21.7 14.5 21.7

30 17.5 25.8 26.7 22.9 15.3 23.2

ET = 15.2 × TDTMU, with a maximum value of 20 TMU.

MTM-1: Eye Travel Time and Eye Focus - ET and EF

D = the perpendicular distance from the eye to the line of travel T.

T = distance between points from and to which the eye travel.

EF (Eye Focus Time) = 7.3 TMU

AWM

!

!

MTM-1: Move - M(X)(Case)(Wt.)

Distance Moved (X in.)

Time (TMU) Weight Allowance

Case and DescpritionA B CHand in

Motion BWt. (lb)

up to FactorConstant (TMU)

≤ 0.5 2.0 2.0 2.0 1.7 2.5 0 0

A - Move object to other hand or against stop. !!B - Move object to approximate or indefinite location. !!C - Move object to exact location.

1 2.5 2.9 3.4 2.3

2 3.6 4.6 5.2 2.9 7.5 1.06 2.2

3 4.9 5.7 6.7 3.6

4 6.1 6.9 8.0 4.3 12.5 1.11 3.9

5 7.3 8.0 9.2 5.0

6 8.1 8.9 10.3 5.7 17.5 1.17 5.6

7 8.9 9.7 11.1 6.5

8 9.7 10.6 11.8 7.2 22.5 1.22 7.4

9 10.5 11.5 12.7 7.9

10 11.3 12.2 13.5 8.6 27.5 1.28 9.1

12 12.9 13.4 15.2 10.0

14 14.4 14.6 16.9 11.4 32.5 1.33 10.8

16 16.0 15.8 18.7 12.8

18 17.6 17.0 20.4 14.2 37.5 1.39 12.5

20 19.2 18.2 22.1 15.6

22 20.8 19.4 23.8 17.0 42.5 1.44 14.3

24 22.4 20.6 25.5 18.4

26 24.0 21.8 27.3 19.8 47.5 1.50 16.0

28 25.5 23.1 29.0 21.2

30 27.1 24.3 30.7 22.7

MTM-1: Turn and Apply Pressure - T and AP T(Wt.)(angle)

Weight

Time (TMU) for Degrees Turned

30 45 60 75 90 105 120 135 150 165 180

Small: 0 - 2 lb 2.8 3.5 4.1 4.8 5.4 6.1 6.8 7.4 8.1 8.7 9.4

Medium: 2.1 - 10 lb 4.4 5.5 6.5 7.5 8.5 9.6 10.6 11.6 12.7 13.7 14.8

Large: 10.1 - 35 lb 8.4 10.5 12.3 14.4 16.2 18.3 20.4 22.2 24.3 26.1 28.2

Applying Pressure Case A - 10.6 TMU, and Case B - 16.2 TMU

AWM

!

!!

MTM-1: Grasp - G(Case)

CaseTime

(TMU) Description

Pick Up Grasp

1A 2.0 Small, medium or large object by itself, easily grasped.

1B 3.5 Very small object or object laying close against a flat surface.

1C1 7.3 Interference with grasp on bottom and one side of nearly cylindrical object. Diameter larger than 0.5”.

1C2 8.7 Interference with grasp on bottom and one side of nearly cylindrical object. Diameter is 0.25” - 0.5”.

1C3 10.8 Interference with grasp on bottom and one side of nearly cylindrical object. Diameter less than 0.25”.

2 5.6 Regrasp

3 5.6 Transfer Grasp

Object jumbled “Search occurs”

4A 7.3 Larger than 1” x 1” x 1”

4B 9.1 Between 0.25” x 0.25” x 0.125” and 1” x 1” x 1”

4C 12.9 Less than 0.25” x 0.25” x 0.125”

5 0 Contact, Sliding or Hook Grasp

MTM-1: Position and Disengage P(Class)(Symmetry)(Ease) D(Class)(Ease)

Position Disengage

Ease of Handle Ease of Handle

Class of Fit Symmetry Easy Difficult Easy Difficult

1 - Loose No pressure required. S 5.6 11.2 4.0 5.7

SS 9.1 14.7

NS 10.4 16.0

2 - Close Light pressure required. S 16.2 21.8 7.5 11.8

SS 19.7 25.3

NS 21.0 26.6

3 - Tight Heavy pressure required. S 43.0 48.6 22.9 34.7

SS 46.5 52.1

NS 47.8 53.4

MTM-1: Release - RL(Case)

Case Time (TMU) Description

1 2.0 Normal release performed by opening fingers as independent motion.

2 0 Contact release.

AWM

Chapter 14 - Work Sampling !It is a method for analysing work by taking a large number of observations at random times. !Theory of work sampling It is the fundamental law of probability; at a given instant, an event can be either present or absent. Statisticians have derived the following expression to show the probability of x occurrences of an event in n observations.

! , p (probability of single occurrence), q (probability of an absence occurrence = 1 - p), and n (number of observations). Normal Distribution is a satisfactory approximation of this binomial distribution when n is large.

We have a mean of p, then the standard deviation !

For the confidence interval (C.I) consider ! as the acceptable limit of error “l”,

" , l can expressed as the limit for which variation in p is allowed.

"

! Work Sampling Chart Control Chart !!

UCL - Upper Control Limit, LCL - Lower Control Limit. !!Standard Time using work sampling

!

" .

!!

p + q( )n = 1

σ p =p ⋅qn

=p ⋅ 1− p( )

nzα 2 ⋅σ p

l = zα 2 ⋅σ p = zα 2p ⋅ 1− p( )

n

l2 = zα 2( )2 p ⋅qn ⇒ n =zα 2( )2 p ⋅q( )

l2, For C. I = 95%, α = 0.05, zα 2 = 1.96, then, n =

1.96( )2 p ⋅ql2

=3.84( ) p ⋅q

l2

l = 3σ p = 3p ⋅qn

= 3 p 1− p( )n

,

UCL = x + l, LCL = x − l, x = p

OT = observed time = TPR

× nin, T "total time of the sample", PR "total production rate",

ni " number of occurences per element i ", n " number of observations ".

NT = OT × R100

= TPR

× nin× R100

, ST = NT 1+ allowance%( )

AWM

Appendix A Worker and Machine Chart The first step is to draw the heading row:

Idle time can be found in two types: • Operator idle: when all machines are running and operator have to wait until a machine stops. • Machine idle: when operator is busy loading and unloading another machine while a machine

has stopped. Total idle time can found by summing all the idle times in one cycle. Oi = (L+m) - (n • (L+w)), Mi = (n • (L+w)) - (L+m). Example: The machines take 1 min. to load and unload, and then 1.5 min. to run, the operator takes 0.08 min. to walk between the machines.

From the above chart, we can calculate the cycle time, which is 3.24 min., and we can observe that M1 finishes Running at Time = 2.5, while the operator return to M1 at Time = 3.24, therefore, there is machine idle time = 3.24 - 2.5 = 0.74 min. How about having only 2 machines?

we can see that after loading and unloading M2, operator walks back to M1, but M1 is still running, this an operator idle, which can be calculated as 2.5 - 2.16 = 0.34. !

Time of Start Operation Machine 1 Machine 2 Mn

Write the time of which the operation starts.

Here you write what does the operator do, e.g: loading and unloading M1, or Walking.

In here you include the Loading and unloading, and also the running time. write the start and end time of L/UL and Run

This will start loading and unloading after operator finishes loading and unloading M1, and walks to M2.

Time Operation M1 M2 M3

0 Loading and Unloading M1 0 - L/UL - 1

1 Walking

1 - Running - 2.51.08 Loading and Unloading M2 1.08 - L/UL - 2.08

2.08 Walking

2.08 - Running - 3.582.16 Loading and Unloading M3 2.16 - L/UL - 3.16

3.16 Walking idle3.16 - Running - 4.66

3.24 Loading and Unloading M1 3.24 - L/UL - 4.24

Time Operation M1 M2

0 Loading and Unloading M1 0 - L/UL - 1

1 Walking

1 - Running - 2.51.08 Loading and Unloading M2 1.08 - L/UL - 2.08

2.08 Walking

2.08 - Running - 3.582.16 idle

2.5 Loading and Unloading M1 2.5 - L/UL - 3.5

3.5 Walking 3.5 - Running - 5.0

AWM

Line Balancing Example will illustrate the procedure,

!!!!!!!At beginning we should construct a table with all the elements of the assembly.

1 indicates that the column element is depending on the row element. Second Step; rewrite them in a table while ranking them. We should also calculate the cycle time. The cycle time for this example is 5.33 min. (calculated from Rp with 8hr. / day ):

8* - we interchanged the place of 8 so we minimize the idle time of w.s 2, this can only be done if the precedence is completed. Total number of workstations is 4, and total idle time is 2.91. The LBE will be 86.4%. • Special case where Te is more than Tc, we break the element into two part with parallel workstations.

0 1 2 3 4 5 6 7 8 9 10 RPW Rank

0 1 1 1 1 1 1 1 9.42 3

1 1 1 1 1 1 1 1 1 14.11 1

2 1 1 1 1 1 1 1 12.87 2

3 1 1 1 1 1 1 8.66 5

4 1 1 1 1 1 6.59 7

5 1 1 1 1 5.12 8

6 1 1 1 2.72 9

7 1 1 1 1 9.01 4

8 1 1 1 6.85 6

9 1 1 2.1 10

10 1 1.45 11

Work Unit RPW Te Precedence Cumulative Te Workstation idle / w.s

1 14.11 1.24 - 1.24 1

2 12.87 0.84 1 2.08 1

0 9.42 0.76 - 2.84 1

7 9.01 2.16 2 5 1 0.33

3 8.66 2.07 0 2.07 2

4 6.59 1.47 3 3.54 2 1.79

8* 6.85 4.75 7 4.75 3 0.58

5 5.12 2.40 4,2 2.40 4

6 2.72 0.62 5 3.02 4

9 2.1 0.65 6,8 3.67 4

10 1.45 1.45 9 5.12 4 0.21

AWM

Work Unit

Estimated Work Unit Time (min.)

Work Unit

Estimated Work Unit Time (min.)

0 0.76 6 0.62

1 1.24 7 2.16

2 0.84 8 4.75

3 2.07 9 0.65

4 1.47 10 1.45

5 2.40 Rp = 90 unit / day