WORK MEASUREMENT

Saravanan J

INTRODUCTION

• Work measurement is the application of techniques designed to establish the time for a qualified worker to carry out specified jobs at a defined level of performance.

• We have seen how total time to manufacture a product is increased by:adding undesirable features to product,bad operation of the processes, and ineffective time added because of worker and management.

• All this leads to decreased productivity.

INTRODUCTION

• Method study is one of principal techniques by which work content in the product manufacture or process could be decreased.

• Method study is, then, a technique to reduce the work content mainly by eliminating unnecessary movements by workers and/or materials and/or equipments.

• However, even after that, there could be substantial unnecessary time taken for the process because of lack of management control and/or inaction of worker.

INTRODUCTION

• Work measurement (WM) is concerned with investigating, reducing and eliminating ineffective time, whatever may be the cause.

• WM is the means of measuring the time taken in the performance of an operation or series of operations in such a way that the ineffective time is shown up and can be separated out.

• In practice, proving existence of the ineffective time is the most difficult task.

• After existence is proved, nature and extent is easy to see!

INTRODUCTION

• WM is also used to set standard times to carry out the work, so that any ineffective time is not included later.

• Since, standard times are set for all the activities through WM, it has earned bad reputation amongst workers.

• Major reason for that has been the initial focus of the WM methods, which essentially targeted only the worker controllable ineffective times.

• Management controllable ineffective times were ignored traditionally.

INTRODUCTION

Two critical issues in work study:

1. Method study should precede the work measurement, always.

2. Elimination of management controllable ineffective time should precede the elimination of the ineffective time within the control of the workers.

OBJECTIVES OF WM

• To determine the standard cost and as an aid in preparing budgets.

• To balance the crew activities and those jobs requiring several workers.

• To determine scheduling and planing work.• To determine effectiveness of the machine.• To balance production lines for new models or new

products.• To make cost estimate of new products.

OBJECTIVES OF WM

• To determine time standards to be used for providing a basis for wage incentive plans.

• To determine time standards to be used for providing a basis for labour cost control.

COMPONENTS OF WM

• Element - An element is distinct part of specified job selected for convenience of observation, method and analysis

• Performance rating- Rating speed of the operator is matter of judgement on the part of time study analyst .

• Allowance - It's time allow the worker to recover from fatigue and to attend the personal needs.

• Standard time - The time consumed from an avg worker, at an avg speed, under normal working conditions.

COMPONENTS OF WM

ELEMENT • A repetitive element is an element which occurs in

every work cycle of the job. • An occasional element does not occur in each work

cycle of the job, but which may occur at regular or irregular intervals. e.g. machine setting.

• For a constant element, the basic time remains constant whenever it is performed. e.g. switch the machine on.

• A variable element is an element for which the basic time varies in relation to some characteristics of the product, equipment or process, e.g. dimensions, weight, quality etc. e.g. push trolley of parts to next shop.

COMPONENTS OF WM

• A manual element is an element performed by a worker.

• A machine element is automatically performed by a power-driven machine (or process).

• A governing element occupies a longer time than any of the other elements which are being performed concurrently. e.g. boil kettle of water, while setting out teapot and cups.

• A foreign element is observed during a study which, after analysis, is not found to be necessary part of the job. e.g. degreasing a part that has still to be machined further.

COMPONENTS OF WM

PERFORMANCE RATING

observed performance

performance rating = x 100

standard performance

COMPONENTS OF WM

ALLOWANCE

• In addition to including relaxation allowances, short rest pauses could be added over the period of work for an operator.

• Start-up / shut-down allowance

• Cleaning allowance

• Tooling allowance

• Set-up / change-over allowance

• Reject / excess production allowance

• Learning / training allowance

• Policy allowance is an increment, other than the bonus increment, applied to standard time to provide a satisfactory level of earning for certain level of performances under exceptional conditions.

COMPONENTS OF WM

STANDARD TIME

NORMAL (OR) BASIC TIME =

Rating Standard

Rating Observed timeObserved x

STANDARD TIME = NORMAL TIME +ALLOWANCE

TECHNIQUES FOR WM

• Time study• Synthesis from standard data• Pre-determined motion time system [PMTS]• Analytical estimating• Work sampling

TIME STUDY

1. Recording the times and rates of working for the elements of a specified job carried out under specified conditions,

2. Analyzing the data so as to obtain the time necessary for carrying out the job at a defined level of performance.

STEPS IN TIME STUDY

• Break the job elements.• Record the observed time for each elements by means

of different techniques.• Establish elemental time values by extending

observed time into normal value for each element by applying a rating factor.

• Assess relaxation allowance for personal needs , physical and mental fatigue invloved in carrying out each element.

• Add contigency allowance , if any , to arrive at the standard time to do the job.

STEPS IN TIME STUDY

Observed time

Normal time

Work content

Standard time

applying rating factor

add relaxation allowance

add contigency and other

allowances required

SYNTHESIS FROM STANDARD DATA

• In many industries , repetitive nature are used in batch production, in these cases we can use synthesis technique.

• In this synthesis use standard time is computed by adding various elemental times which constitute the work.

• Standard data are made available for the most known elemental operations like preparing ,setting , manipulating, removing, clearing,holding and tightening.

PMTS

• It's defined as a WM technique by which normal or basic times are establishes for human motions and these time values are used to build up a time for a job at defined level of performance.

• It involves thinking or observing through a job , recording job elements, recording pre established motion units and calculating performance standard.

• It's an improvement over motion study , its affording detailed motion analysis , it make to set a measure of time thata series of motion ought to take

ANALYTICAL ESTIMATING

• It's used to determine the time values for jobs,having long and non- reptitive operations .

• Time values detemined by using synthetic data , if synthesis data in not available.

• Estimator shoud have adequate experience of estimating, motion study, time study and use of standard data.

WORK SAMPLING

• It's a technique of WM , its does not involve stopwatch measurement , as do many of other technique;

• Instead , its based on simple random sampling techniques ,

derived from statistical sampling theory,• Work sampling known by follwing names :

1.active sampling

2.ratio delay

3.snap reading and observing• Purpose of sampling is to estimate at what proportion of a

worker's time is devoted to work activities

USES OF WM

• To compare the efficiency of alternative methods. Other conditions being equal, the method which takes the least time will be the best method.

• To balance the work of members of teams, in association with the multiple activity charts, so that, as far as possible, each member has tasks taking an equal time.

• To determine, in association with man and machine multiple activity charts, the number of machines an worker can run.