Work Measurements and Flow Analysis

Lecturer: Serap Ulusam Seçkiner

Work Measurements and Flow Analysis• Second method is work measurement after motion study.• Determining nonactive times in total work duration.

• Work performance standards are important for man and machine

• Detemining performance standard is main element and helps;– Wage payment– Budget cost– Production cost

• There are various methods for work measurement and methods change according to job configuration and features.

• In this section, work measurement methods will be introduced and information about flow analysis.

Definitions • Work measurement may be used to determine the standard number of minutes taht aqualified

properly trained, and experienced person should take to perform a specific task or operation when working at a normal pace.

• This time standard may be used for planning and scheduling work, for cost estimating, or for labor cost control or it may serve as the basis for a wage incentive plan.

• Although standard data, predetermined time systems and work sampling are widely used for establishing time standards

• Perhaps the most common method of measuring work is stop-watch time study or electronic time study.

• The operation to be studied is divided into small elements each of these elements and the the times are added together to get the total selected time for performing the operation.

• The speed exhibited by the operator during the time study is rated or evaluated by the time study observer and the selected time is adjusted by this rating factor so that a qualifed operator working at a normal pace can easily do the work in the specified time

• This adjusted time is called the normal time. To this normal time is added allowances for personal time, fatigue, and delay , the result being the standard time for the task.

Definitions

• Qualified worker: physical sufficiency, intelligence, train and skills for safely working, quality and amount.

• Determined task (Task bringing standard) : Task is reported point of view production methods

• Determined productivity level: Qualified worker performs task with great motivation and non overloading during on a day or one shift. Finally task gives average output.

Importance of work measurements

• Motion study= eliminate nonnecessary activities

• Work measurement= eliminate nonactive times in total time.

• Work measurement assures some techniques for determining required time

• Determination of standard time (nonactive times)

• Observation and reasoning for nonactive times

• Work measurement is a tool that shows the behaviour of management and workers

• There is a reaction for work measurement (labor union)

• Actually, nonactive times are due to partial management functions.

• Management functions must be coped with more than worker functions’s control

• Nonactive times and its amount are important. Then it is important to take necessary precautions for obtaning performance standards. This can be possible only with trained worker and removed nonnecessary activities.

Subjects and application fields

• Comparing alternative methods: The best method has the shortest time.

• Workload balancing among workers. Tasks must be divided equally. (Multiple process chart), Equall task times.

• Assigning optimal machine number (Man and Machine charts)

• Production planning and scheduling (capacity planning, man, machine, equipment requirements)

• Detemination of sale pricing and order release dates

• Workbench usage rates are used to determine worker performance standards. This helps scheduling of incentive payments,

• To obtain info for direct labor cost and suppliying standard cost with stable.

• Preparing report for man, machine and shopfloor performances

Application types

• Two alternative method

– Direct work measurement (direct observation on task) for example; time study, and work sampling

– Indirect work measurement (indirect method not on the task) with standard times are measured by standard data and formulation. These are estimations. In addiation, synthetic time system is used for determining standard times(Predetermined time systems)

Method

• Stages– Selecting the task– Reporting all data for work conditions, used method

and task elements in method.– Analysing all data in detail and finding the best

method– Work measurement with suitable technique and

graded performance– Calculating standard time with allowances.– Registration operations and activites – Applicatin of standard time continuity.

Flow Analysis

• It is necessary to divide task to flow segments and determine

• Flow type is related with both worker and production equipment

• Work researcher can determine task flow in detail and prevents misunderstanding

• Classification of task gives interaction man and machine and productivity level.

Setup and Process Times

• Setup times– Obtaining task order,– Techinical drawing related with task – Loading or unloading machineSetup times are showed with R

• Process Times– Three types

• Complete interaction (assembling, reading technical drawing,• Unaffected flows (solder, welding, driving),• Conditional affected flows (chart control, automatic command

process

Classification of flows

• Man flows

• Machine Flows

Man Flow Types

• Generally, symbol is M

• MI: at work• ML:out of work• MR: to close temporarily• • The other flow types

• MH: Main activities• MN:Auxilary activities

Comparing main and auxilary activities

Main Activities Auxilary Activities

Processing work piecePaintingTypewriting,Observing automated lathe process

Bringing work piece and storageMixing paintsAttaching new paper to machineCounting pieces andParçaları sayma, reading directives

Man flows types

• Additional activities:MZ

• To have break:MA

• Delaying:MS

• Rest: ME

• Personal:MP

• Undetermined:MX

Machine flow types

• Generally, symbol B is used.

• Machine in process:BI

• Machine down: BL

• To close temporarily:BR

Machine flow types

• Main usage:BH• Auxiliary usage:BN• Additional usage:BZ• To have break: BA • Delaying:BS• Rest: BE• Personal:BP• Undetermined:BX

Man and Machine Flow Types (MPM-REFA, 1985)

Flow types applications

• Example 1: Carrying material with wheelbarrow and elevator

Flow types

wheelarrow elevator

No Flow segment M B M B

1 Loading MN BN MN BN

2 Return with load MH BH MA BH

3 Unloading MN BN MN BN

4 Come back with unload

MN BN MA BN

• Example 2: 500 kg grape will be pressing

Flow Types

No Flow segment M B

1 Filling grapes to press MN BN

2 Closing press MN BN

3 Automated pressing MA BH

4 Automated get back MA BN

5 Opening press machine MN BN

6 Taking residue and putting floor MN BN

7 Lifting residue from floor MZ BS

Determining allowance times

• Order times

• Loading times

Ordering times

Ordering timeT

Setup timetr

Setup main time

trg

Setup rest timetrer

Setup distributio

n timetrv

Main timetg

Rest timeter

Distribution time

tv

Process timeta = m . te

Unit timete

Loading times

M.L times TbB

M.L. Setup time trB

M.L.setup main timetrgB

M.L.setup distribution time

trvB

M.L main timetgB

M.L.Process timetaB = m . teB

M.L.Unit timeteB

M.L. distribution timetvB

Main Time

trg : Setup main timetg : main timetrgB : Machine loading setup main timetrB : Machine loading main time

trg ve trgB setup stage, the others refer producing unit good, tg main time contains tt (activity) and tw(waiting).

tgB machine main time, This contains main usage time (th), auixilary usage time(tn) and interruption time (tb)

tg = tt + tw

tg = ΣtMH + ΣtMN + ΣtMA

tgB = th +tn + tb

tgB = ΣtBH + ΣtBN + ΣtBE +ΣtBA

Distribution Timestv distribution time, this time contains objective (ts) and personal (tp) distribution time. objective (ts) distribution time contains additional times(MZ) and delaying times

(MS). Personal (tp) distribution time contain personal times (MP).

tv = ts + tp

tv = ΣtMZ + ΣtMS + ΣtMP

Percentage of distribution time is as follows;Zv is percentage of objective and personal distribution times

Zv = Zs + Zp

If Zv is given, tv can be found:

tv = (Zv/100)* tg

Machine distribution time(tvB) can be found same way. But (BE) is extracted.tvB = (Zv/100)* (th + tn + tb – ΣtBE)

Rest times

ter rest time is percentage of main time.

Zer (%) = (ter / tg) * 100

Standard time

Standard time(te) contains main time, main rest time and distribution time

te1 = tg + ter + tv

or it can be found with percentage of rest and distribution times;

te1 = tg + (Zer+Zv)/100 * tg

Machine unit time;

teB = tgB + tvB

Process and setup times

ta process time (for 1):ta = m . te

tr setup time is related with worker, Order time and Machine loading

time are found as follows:

tr = trg + trer + trv

trB = trgB + trvB

Order and Machine loading times

T order time contains setup and process times

T= tr + ta = tr + m . te

Order times can be many process, production amount is multiplied with unit

times and added eachother.

T= tr + m1 . te1 + m2 . te2 + m3 . te3 + ......

Order can occur from many part, TbB machine loading time is found as

follows:TbB= trB + m1 . teB1 + m2 . teB2 + m3 . teB3 + ......

EXAMPLES