predetermined time study

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Predetermined Time Study

Predetermined Time Systems are techniques of motion study and time standards

development. The motions of the work or task performed are recorded. Each basic motion has

a time value associated with it. Once all the motions for the task have been recorded, the timevalues are totalled and the standard time for the operation is developed.

Stop-watch Time Study vs. Predetermined Motion and Time Study

PMTS is a world recognized motion-based method of measuring work. By carefully

describing all of the motions required to perform a task, each motion is tagged with a specific

code and assigned time value. An entire task is measured by synthesizing all the motions

identified in a job.

Predetermined Motion and Time Study (PMTS) is

- More reliable

- More consistent

- More accurate

- Initial high investment

- Benchmarking tool

First, the task you study has to be precisely defined by motions involved. This requires a

complete understanding of the operation. Once motions are defined, then multiples of

repeated individual motions are retrieved from the systems database. Individual motion

times are combined, and allowance is factored in. The resulting total is a time standard for thetask.

Many medium to large factories are moving away from stop-watch time study to PMTS.

While PMTS is proven to be able to produce more reliable and consistent standard times, it is

an expensive investment, initially, however. There are two aspects: training and IT

investments.

Unlike stop-watch time study, PMTS is harder to learn and apply. There is a body of

knowledge that must be fully acquired by any PMTS analyst. Extensive training in methods

and information technology must be acquired before you can effectively reap the benefits

from it. Some costs are also incurred from instructor-led training and specialized softwarewhich usually has annual subscription fees.

One should know that time standards are the most fundamental elements in all operations in a

factory. Data for scheduling, staffing, line balancing, wage payment, costing, etc The cost

of inaccurate or poor data quality adds up and becomes even more costly.

Globalization is driving an increasing number of companies to adopt PMTS today. In the

open leveled competing ground, winners will always be the one who has accurate information

to enable them to make precise strategic decisions.
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Historical Development

One of the oldest examples of a predetermined motion time system is the Methods Time

Measurement approach, which first appeared in 1948. This approach concerned itself with

mainly manual tasks, such as work on an assembly line or running a set of carding frames in

a textile plant. As such, the focus was on repetitive tasks that required a fair amount of

dexterity. Over time, three different incarnations of the MTM method developed, with each

method focusing on a different types of tasks, ranging from manual short duration processes

to processes that took longer time to create and were not as manually focused.

Along with MTM, the Maynard Operation Sequence Technique (MOST) is a commonly

employed predetermined motion time system today. First introduced in 1972, the original

MOST also focused heavily on short term manual tasks that were repetitive in nature.

However, with the continuing expansion of industry so that many countries no longer used

manufacturing as the basis for evaluating productivity, MOST also began to develop

additional approaches that would help to quantify tasks that were less repetitive in nature.

Today, there are several variations of MOST including BasicMOST, MiniMOST,

MaxiMOST and AdminMOST.

While a predetermined motion time system is an attempt to measure time needed to perform a

given task properly and efficiently, PMTS is a different approach to the more simplistic time

study. With a time study, the results are often based on observation, with a stopwatch used to

monitor the time needed to successfully complete a task. A predetermined motion time

system digs a little deeper by breaking the task down into steps and quantifying each step in

the process. The quantified times for each step is added together to arrive at the total amount

of time needed to perform the task.

General Procedures:1. Summarize all left-hand and right-hand motions required to perform the job properly

2. Determine between the left and right-hand motion which is the limiting motion.

a. Limiting Motion among simultaneous motions, it has the largest TMU value.

b. Non-limiting Motion has the smaller TMU value, which is either encircled

or deleted, and is not included in the computation of the normal time.

3. Refer to the tables and determine the corresponding TMU values for each motion

depending on the conditions described for each motion.

4. Summarize TMU values.

5. Apply appropriate allowances.

a. The addition of fatigue allowance is not necessary because MTM values are

based on a work rate that can be sustained at steady state for the working life

of a healthy employee.

MTM -1

- Methods Time Measurement

- Gives time values for the fundamental motion of REACH, MOVE, TURN, GRASP,

POSITION, DISENGAGE, and RELEASE
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- A procedure which analyzes any manual operation or method into the basic motions

required to perform it, and assigns each motion a predetermined time standard which

is determined by the nature of the motion and the conditions under which it is made.

- 1 TMU = 0.00001 hour

- MTM-1 data are the results of frame-by-frame analyses of motion picture films ofdiversified areas of work. The data taken from the various films were rated by the

Westinghouse technique, tabulated and analyzed to determine the degree of difficulty

caused by variable characteristics

MTM-2

- Application of MTM where less-refined data where developed suitable for the

majority of the motion sequences.

- A system of synthesized MTM data and is the second general level of MTM data.

- Based exclusively on MTM and consists of the following:

o Single basic MTM motions

o Combination of basic MTM motions

- Application:

o The effort portion of the work cycle is more than 1 min.

o The cycle is not highly repetitive

o The manual portion of the work cycle does not involve a large number of

either complex or simultaneous hand motions.

MTM 3

- Developed to supplement MTM-1 and MTM- 2

- Helpful in work situations where an interest in saving time at the expense of some

accuracy

- Can be applied in about one-seventh the time of MTM-1

- Cannot be used for operations that require either eye focus or eye travel time

- Consists of only 4 categories of manual motion with 2 cases: A and B determined bythe correction

o Handle (H) purpose is to get control of an object with the hand or fingers

and placing the object in a new location

o Transport (T) purpose is to move an object to a new location with the hand

or fingers

o Step and Foot Motions (SF) same with MTM-2

o Bend and Arise (B) same with MTM-1

MTM V


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- Developed by Svenska MTM Gruppen (Swedish)

- Applicable for metal cutting operations

- Of particular use with short runs in machine shops

- Provides for work elements such as:

o Bringing the work to the jig, fixture, or chuck, removing the work from the

machine and placing it aside

o Operating the machine

o Checking the work to ensure quality of output

o Cleaning the nip point area of the machine, to maintain facility output and

product quality

- Does not cover time involving different speeds and feeds

- Use this system to establish setup times for all typical machine tools

MTM C

- A two-level standard data system used to establish time standards for clerical-related

tasks

- Both levels are traceable from MTM-1

-

-Level 1 Elements Symbol

Get Place 11XXXXOpen Close 21XXXX

Fasten Unfasten 31XXXX

Organize File 4XXXXX

read Write 5XXXXX

Keyboarding 6XXXXX

Handling 7XXXXX

Walk Body Motions 8XXXXX

Machines 9XXXXX

-Level 2 Elements Symbol

Aside A

Body Motions B

Close C

Fasten F

Get G

Handling H

Identify I

Locate File L

Open O

Place P

Read R

Typing T

Unfasten U

Write W


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PTS Applications

1. Standard Data Development

a. With standard data, standard times for operations can be set much faster than

by the laborious procedure time study

b. Methods analyst break each element down into the fundamental motions.

Once the basic values are assigned and the variables are determined, the

resulting algebraic equation allows the rapid calculation of time

c. Predetermined basic motion times have necessarily been developed for

standard performance, therefore no ratings are needed. Eliminating the one

step which is most open to controversy and uncertainty

2. Methods Analysis

a. With PTS, developing a motion or method analysis is done in greater

numerical detail, identifying better ways of eliminating ineffective therbligs

b. Opportunities for improvement

i. Elimination of body motions, such as Bend and Arise

ii. Reduction of case levels, especially case C motions

iii. Minimizing Reach distances

iv. Avoiding the lifting of heavy parts

v. Eliminating operations that require eye travel and focusvi. Prepositioning tools, parts, materials

predetermined time study

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