Work regulations

Labor regulations play an important role in the growth of labor productivity, therefore it is necessary to achieve maximum effectiveness in the employment of the work force, and of material resources in the production process.

The following work aims to explain in a simple way what is understood by LABOR STANDARDS, starting with a detailed explanation of the concept of STANDARDS and the types of classification of standards that exist. The STRUCTURE OF THE WORKING DAY and the corresponding classification of TIME EXPENSES are also explained. Subsequently, the steps to follow for a STANDARD STUDY, the STANDARD METHODS AND TECHNIQUES, including in some cases some examples of these techniques, are explained. Finally, the PROCEDURE FOR THE PREPARATION OF THE STANDARDS is explained, be it of PRODUCTION or TIME.

labor-regulation

CHAPTER I

BASIC CONCEPTS AND PRINCIPLES OF LABOR REGULATION.

1.1.- Concept of Standard. Concept analysis.

“The norm is the expression of the living work cats necessary for the execution of a work activity under certain technical-organizational conditions, by a worker (or group of workers) who has (n) the required qualification and executes (n) their I work with skill and medium intensity ”.

Let's carry out each part of the concept of standard in detail.

The first thing that is expressed is that the norm is the living labor expense necessary for the execution of a labor activity, that labor expense is expressed as a time norm, as a production norm or as a service norm, depending on the way of expressing it how the worker better understands his social duty and how its control is easier.

Second, the concept expresses that the norm is the living labor expense necessary for the execution of a labor activity, it does not express the labor expense that a given worker invests, since a worker can invest more time than necessary if they are introduced unnecessary actions and the established procedure is altered, therefore they consume time and contribute nothing to the transformation of the work object; On the contrary, it can do the job in less time, eliminating planned steps and thus altering the established procedure, which can negatively influence quality.

On the other hand, the concept of norm continues to express that it is the expression of the living labor expenditure necessary for the execution of a work activity under certain technical-organizational conditions.

This idea is very important and implies that the execution time of a job depends on the organization of established production and work, that is: on the division and cooperation of work, on the content of work, on the organization of the transfer of the materials, the way of doing the operation and the working conditions, among others.

That the technical - organizational conditions in which the work is carried out changes, implies carrying out the revision of the standard with the purpose that it again expresses the necessary work expense; Technical-organizational conditions change when the team, the form of division and cooperation of work, raw materials and / or materials, work content, working conditions, work methods, etc. change.

This concept goes on to say that it is the expression of the living labor expenses necessary for the execution of a work activity under certain technical - organizational conditions, by a worker (or group of workers).

Here it must be clear that it is appropriate to establish collective rules when there is a chain process and not individual rules.

It also states that it is the expression of the work expenses necessary for the execution of a work activity under certain technical - organizational conditions by a worker (or group of workers) who has the required qualification.

This sentence emphasizes that the standard is made so that it can be fulfilled by a worker who has the necessary qualification to perform the work, so the standard cannot be determined from the observation and measurement of the execution times of the work of workers without the appropriate qualification, as well as the fact that it cannot be fulfilled by someone who does not have the qualification does not imply the need to modify it, nor should it be modified because a highly qualified worker exceeds it.

Finally, the concept of norm proposes that it is the expression of the living labor expenses necessary for the execution of a work activity under certain technical-organizational conditions by a worker (or group of workers) who has the required qualification and executes their work. with skill and medium intensity.

This last idea is of great importance, as it indicates that when preparing the standard, the need to properly select the workers who will be the object of time measurement to define the standard must be taken into account, since not even the most skillful can be selected nor the most skilled, as well as those who work with a very high or very low intensity. Once the standard has been defined, overcompliance or non-compliance that occurs as a result of the worker working with a greater or lesser intensity than normal, cannot imply the need to modify the standard.

1.2.-Classification of standards.

The rules can be classified according to different criteria, including:

According to the way of expressing the work expense

According to the way of application.

According to the field of application

In this material we will refer only to the rules according to the way of expressing the work expense.

1.2.1.- Classification of the rules according to the way of expressing the work expense

According to this criterion, the standards are classified into: time standards, production or performance standards, and service standards.

Time Norm: It is one that expresses the time necessary for the fulfillment of a work unit (operation, article, etc.) by a worker or group of workers.

It is used when the worker performs different operations that require different execution times, or when he performs an operation whose conclusion exceeds the limits of the normal working day.

Production or Performance Standard: It is one that expresses the number of work units (operations, articles, etc.) that must be prepared by a worker or group of workers in a work day.

The production or performance standards are used mainly in those cases in which the time of realization of the work unit is relatively short and the worker within the work day can do it several times. It is mainly used in series and mass processes

Service Standard: It is one that expresses the labor content of a worker or group of workers in a certain period of time (number of looms to be attended by a weaver, number of tables to be attended by a clerk, direct workers to be attended by a worker auxiliary, etc.).

The service standard is used:

• When the worker performs heterogeneous operations, where it is not possible to determine their duration with precision or where the necessary administrative control exceeds the logical and possible frameworks from the economic point of view.

• In highly mechanized, automated and apparatus-based processes, where the main work is carried out by the equipment and the work of the worker is directed to control and service activities thereof.

CHAPTER II

CLASSIFICATION OF TIME EXPENSES.

Next we will see the structure of the working day, with the corresponding classification of time expenses and their symbols, used for years in the country for the study of work expenses and the determination of time and production standards in the processes.

2.1.- Structure of the working day for the study of the processes.

Labor Day (JL): It is the time during which, according to current legislation, all workers must remain dedicated to work in their workplace. For its study it is divided into:

• Work

time • Interruption time.

Working time (TT): It is the time that the worker is working, either in really productive tasks, in tasks unrelated to their work content or in unnecessary work. It is divided into:

• Work time related to the task.

• Unrelated work time.

Task-related work time (TTR): It is the one that the worker uses to carry out the operation or operations that are given to him by the characteristics of the production process and by his qualification, he works rationally and efficiently in his job, in the which performs activities that transform the work object. It is divided into:

• Preparation time - conclusive.

• Operating time.

• Service time.

Preparative - conclusive time (TPC): It is the time that the worker (or brigade) uses to prepare the fulfillment of a given job and the actions related to its completion.

This type of expense is manifested in the following activities:

• Obtaining the work order.

• Obtaining instruments, devices, etc. and technological documentation.

• The instruction of the order in which the work will be carried out.

• The placement of devices and instruments.

• The adjustment of equipment to the corresponding work regime necessary for the fulfillment of the given task.

• Removing devices, instruments, technological documentation, work order, etc.

The preparatory - conclusive time occurs every time the task changes (either an individual or serial production) and has the peculiarity that its magnitude does not depend on the volume of work to be carried out, but on the complexity of the preparation necessary for it..

Operational time (TO): It is the time used by the worker (or brigade) to change or contribute to the change of the shape, dimensions, properties and position in space of a work object. It is divided into:

• Main time.

• Auxiliary time.

Main time (TP): It is the time that is directly invested in the qualitative and quantitative change of the work object, its dimensions, properties, composition, color, shape or position in space. Examples:

• Roughing time in the turning activity.

• Loading and unloading time in the work of the stevedores.

• Flat sewing time when making a shirt.

• Driving time of the vehicle in the work of the drivers.

Auxiliary time (TA): It is the time that the worker uses to perform the actions that ensure the fulfillment of the main job. At this time the following expenses are included:

• The times to feed the machines with raw materials and / or semi-finished products.

• The times necessary to check the quality of the production carried out.

Service time (TS): It is the time that the worker needs to care for and maintain order and cleanliness in his job, which guarantees productive work. It is subdivided into:

• Technical service time.

• Organizational service time.

Technical service time (TST): It is the time used to maintain the equipment in adequate technical conditions to perform a specific job. To this time they refer:

• The expense of time to replace a worn instrument or part.

• Time expenses for equipment lubrication, etc.

Organizational service time (TSO): It is the time spent in keeping the job in order and working order during the shift. At this time correspond:

• Time expenses to receive and deliver the shift.

• The time expenses for the distribution at the beginning and the collection at the end of the shift of the tools.

• Time spent tidying up and cleaning the work area (including equipment).

Time of work not related to the task (TTNR): It is the time that activities are carried out that are not foreseen in their content or that correspond to other positions to perform, either caused by fortuitous needs of the production or by deficiencies in the organization of the job. The same happens:

• When the worker is transferred to another job, as a result of the absence of another worker and the need to fill the vacancy as it is a fundamental position in the flow.

• When due to deficiencies in the organization, the worker must move to activities of an auxiliary worker, etc.

Interruption time (IT): It is the time during which the worker does not participate in the work process. It is subdivided into:

• Time of regulated interruptions.

• Unregulated outage time

Regulated interruptions time (IRR): It is the time that the worker does not work for reasons foreseen and determined in time, inherent to the work process itself. It is subdivided into:

• Rest time and personal needs.

• Time of interruptions determined by the technology and the established work organization.

Rest time and personal needs (TDNP): It is the necessary time that the worker consumes in order to be able to maintain his normal work capacity. It is subdivided into:

• Break time.

• Time of personal needs.

Rest time (TD): It is the time that the worker must consume in order to recover or prevent the fatigue produced during the work process.

These purposes are compatible with activities such as: the consumption of snacks, so they must be combined.

Time of personal needs (TNP): It is the time that the worker must consume to maintain his personal hygiene and to fulfill his physiological needs.

Time of interruptions determined by the technology and the organization of the work established (TIRTO): The time of interruptions determined by the technology and the organization of the work established, includes the time of interruptions caused by the specific conditions in which the production process is developed. For example:

• Stowage interruptions during the time the crane is carrying the load.

• Interruptions in the work of miners during the wait caused by the explosion of a dynamite charge.

Unregulated interruptions time (TINR): It is the time that the worker does not work due to alteration of the normal work process. It is subdivided into:

• Time of interruptions due to technical - organizational deficiencies in the process.

• Time of interruptions for violation of labor discipline.

• Time for casual interruptions.

• Time of interruptions for other organizational causes.

Time of interruptions due to technical - organizational deficiencies of the process (TITO): It is the time in which the worker does not work as a result of technical and / or organizational deficiencies of the production process. Among them are:

• Lack of tools.

• Lack of raw material.

• Lack of semi-finished products.

• Equipment breakdown.

Time of interruptions for violation of labor discipline (TIDO): It is the time that the worker does not work due to violation of labor discipline. Among them are:

• Late arrivals.

• Unemployed without working.

• Unwarranted conversation.

• Excessive time in the regulated rest.

• Unexcused absence from work.

Casual interruption time (TIC): It is the time in which the worker does not work as a result of the interruption of the work process for totally causal causes. Among them are:

• Stoppages due to weather conditions.

• Lack of energy.

Time of interruptions for other organizational causes (TIOC): It is the time in which the worker does not work as a result of the interruption of the work process for organizational reasons not related to the organization of production. Among them are:

• Collections during business hours.

• Problems in transportation.

• Classes during working hours.

• Problems in the dining room.

• Political activities during working hours.

CHAPTER III

STAGES TO FOLLOW IN A STANDARD STUDY.

To carry out a regulatory study, the following steps must be followed for any method that is used:

• Selection of activities and operations to be regulated.

• Preparation of the observation.

• Carrying out the observation.

• Information processing and analysis.

• Determination of the technical - organizational measures to be implemented and calculation of the standards.

• Implementation.

3.1.- Selection of the activities and operations to be regulated.

The selection of activities and operations to be regulated must be carried out according to an order of priority that is established, those in which the current labor standards are breached or exceeded in a magnitude well above the established parameters must be chosen with priority as normal, the activities and operations that are limiting in the production or service process and those that group a large number of workers and

3.2.- Preparation of the observation.

The preparation of the observation must begin with the study of the working conditions of the workshop and the jobs where the observation is to be carried out. The established production technology, the operating parameters of the equipment, the organization of the positions and their service, among others, must also be studied.

The selection of workers to observe is made depending on the objective of the study:

• If the study is to be carried out to determine work standards, workers who possess the required qualification and perform the work with medium skill and intensity should be observed.

• If they are the work methods, those that have the highest productivity as a result of the work methods used will be selected.

• If we are going to study the causes that motivate non-compliance with the rules, we will study workers who do not comply with them.

Another important aspect that must be taken into account in the preparation of the observation is to guarantee, during the observation period, the adequate supply of raw materials, materials and semi-products, the correct condition of the equipment and the adequate service to the post of job.

During the preparation stage, the method to be used for the observation of each job should also be selected, depending on the characteristics of the work under study and the time available.

Once the method to be used has been determined, the number of observations that must be made to obtain the data with the desired quality will be calculated and the modeling to be used will be prepared.

3.3.- Carrying out the observation.

The third stage of any normative study is observation itself, which is carried out according to the chosen observation method.

3.4.- Information processing and analysis.

In this stage, the results obtained during the observation are processed, calculating the total data and averages of all the times and indices of the studied process, the magnitude of the error, etc.

Subsequently, the causes that originate the loss of time are analyzed, in order to propose the technical - organizational measures that can be applied for their reduction or elimination.

Work times, those not related to the task, service and auxiliary times, should also be analyzed, analyzing the measures that can be taken to achieve the most rational use of man and equipment.

3.5.- Determination of the technical - organizational measures to be implemented and calculation of the standards.

From the analysis of the information and with the knowledge that has been obtained about the existing organizational problems, the technical - organizational measures that must be implemented are defined in order to eliminate or reduce interruptions and unnecessary time expenses as much as possible..

Once this step is carried out, the norm is calculated.

3.6.- Implementation.

This stage includes: preparation for implantation and implantation itself.

The preparation for the implementation includes the entire process of analysis and discussion of the standards with the workers, as well as the implementation of the technical - organizational measures determined in the previous stage and that are essential to achieve the production levels provided for in the standards calculated..

The implementation corresponds to the phase of introduction or application of the standards in the technical - organizational conditions for which they were calculated.

CHAPTER IV

STANDARD METHODS AND TECHNIQUES

4.1.- Study techniques of working time.

The most used working time study techniques are the following:

• Individual detailed photograph (Continuous individual observation).

• Collective detailed photography (Continuous collective observation).

• Sampling by instantaneous observations.

• Timing of operations.

• Timing of elements.

4.1.1.- Individual detailed photograph (Continuous individual observation).

This method consists of making a detailed description of all the activities carried out by the worker within the working day and measuring the duration of each of them, in order to know the level of interruptions and use of the worker and / or equipment, being able to Determine from this information the technical - organizational measures to implement and calculate the work standard.

This method has the disadvantage of having to observe a greater number of workers in order to reach satisfactory conclusions, and therefore studies carried out exclusively by this method take longer to carry out.

For this reason, the use of this method is directed fundamentally to the study of isolated jobs in non-repetitive tasks.

4.1.2.- Collective detailed photography (continuous collective observation).

It consists of making a detailed description of all the activities carried out by a group of workers within the working day, measuring the magnitudes of each of them, in order to know the level of interruptions and use of them, being able to determine from this information the technical - organizational measures to implement and calculate the norm of the group.

This method is applied when we have a group of workers who carry out the same operation or when a group of workers collectively carry out work on the same work object.

This method has the disadvantage that the observer must have great skill and experience.

4.1.3.- Sampling by instantaneous observations.

This method consists of determining the specific weight (%) of each of the work elements and interruptions in relation to the working day and once they have been obtained, determining the absolute magnitude of said times. From the times thus obtained, the technical-organizational measures to be implemented are analyzed and the standard is calculated.

It has the fundamental advantage of being able to observe with a single regulator up to 40-50 workstations, significantly reducing the time to carry out the study.

Taking this characteristic into account, the instantaneous observations sampling method is ideal to be used in places where there is a large concentration of workers who perform repetitive operations and where they have a well-defined work area.

The fundamental disadvantage of the same is in the impossibility of perfecting the working methods through the information captured by this technique.

4.1.4.- Timing of operations.

The method of timing operations consists of measuring the duration of the operation studied by means of a stopwatch and, knowing the breakdown of time expenses of the working day corresponding to the job under study, determining the standard.

This method is used mainly in those jobs that carry out repetitive operations of short duration, and has the advantage that the times obtained through it are very exact.

4.1.5.- Timing of elements.

This method consists of determining the time it takes for the operation under study by measuring the duration of each of its component elements by means of a stopwatch and, knowing the breakdown of time expenses in the working day corresponding to the studied job position, determine the norm.

This method, like the previous one, is used mainly in those jobs where repetitive operations of short duration are carried out.

Its use is advantageous in those processes in which the different operations carried out have common elements. The times obtained through this method are also very accurate.

CHAPTER V

INDIVIDUAL DETAILED PHOTOGRAPH

(INDIVIDUAL CONTINUOUS OBSERVATION)

As we stated in the previous chapter, this method consists of making a detailed description of all the activities carried out by the worker within the working day and measuring the duration of each of them, in order to know the use of the working hours of the workers. themselves.

The observations can be made with a watch (which can be with a second hand or not) or with a stopwatch, and a planchette or table to locate the modeling and make the annotations.

During the observation it is advisable not to burden the worker with illogical questions or mysterious attitudes; On the contrary, according to the degree of confidence obtained, the worker will be asked, when necessary, for information about the work he is doing or the causes of any important interruption to clarify, whether attributable to him or not.

The result of the breakdown of time expenses, as well as the production carried out during the days observed, will allow to reach conclusions about the positions studied in terms of the most appropriate organization and the standard to be implemented.

5.1. - Determination of the number of observations.

Assuming that the population corresponding to the working times of a position with stable work content follows a normal distribution, the number of observations to be made will be determined by means of the expression corresponding to said distribution. The expression, in its general form, is the following:

δ 2. σ 2

N = ---- (1)

s2. x2

Where:

N = Number of observations that need to be made to obtain the mean value of the measured element (x) with the desired accuracy and confidence level.

σ = Standard deviation of the population.

x = Average value of the element measured, determined from an initial sample. In our case it will be the average working time (TT).

s = Desired relative accuracy in the results, expressed in hundredths of a unit.

δ = Constant that depends on the desired level of confidence in the results.

The values ​​of the same for the most used confidence levels are shown in the following table:

To determine the number of photographs to take, it is usual to use a confidence level of 95%, for which δ = 1.960, a value that to facilitate calculations we can approximate to 2, thus obtaining a confidence level of 95.45%.

Substituting in (1) we have:

Four. σ 2

N = ----

s2. x2

On the other hand, experience has shown that in time studies in order to determine work standards, it is convenient to obtain an accuracy (s) of ± 5% in the results, in which case the previous expression is simplified as follows shape:

Four. σ 2

N = -----–

(0.05) 2. x2

σ 2

N = 1600 -– (2)

x2

Now, taking into account that r = R / d, where d is a factor that depends on the size of the initial sample and R the range of said sample; We can substitute in the previous expression and we will have the way to calculate the number of observations based on the range, which is an easier to find dispersion statistic. So:

R2

N = 1600 --– (3)

x2. d2

The following table gives the values ​​of d for different sizes of the initial sample.

TABLE No. 2

VALUES OF d ACCORDING TO SIZE OF THE INITIAL SAMPLE

Sample size d values ​​Sample size d values

2 1,128 7 2,704

3 1,693 8 2,847

4 2,059 9 2,970

5 2,326 10 3,078

6 2,534 11 3,173

In the case of detailed photography, it is recommended to make an initial sample of 3 observations and therefore, the value of d will be 1.69. Substituting in (3) we will have:

R2

N = 1600 ------

(1.69) 2. x2

R2

N = 1600 ------

2.86. x2

R2

N = 560 --- (4)

x2

Where:

N = Number of observations that need to be made to obtain the mean value of the measured element (x) with an accuracy of  5% and a confidence level of 95%.

x = Average value of the element measured, determined from an initial sample of 3 observations. In our case it will be the average working time (TT).

R = Range of the initial sample, that is, the difference between the maximum value and the minimum value.

Once the number of observations has been determined, it is recommended that they be carried out on alternate days, in order to extend the observation period. The observations corresponding to the initial sample are valid to complete the number of observations required.

5.2.- Making the observations.

The realization of the observations by means of the method of Individual Detailed Photography is carried out. The objective is to record, in detail, all the activities carried out by the worker during their working day (whether classified as working time or as interruptions) and measure the time spent on them.

In those cases in which the observation is carried out with a stopwatch, the duration of each activity is recorded directly in the column "duration", subsequently calculating the Relative Error committed, using the following expression.

TR - TC

ER = ----. 100 (5)

TR

Where:

ER = Relative error, expressed in percent.

TR = Real time observed, determined by the difference between the start time (HC) and the end time (HT) of the observation.

TC = Timed time, determined by the sum of the "duration" column.

It should be noted that when observations are made with a chronometer, those in which the Relative Error committed is greater than ± 5% should be discarded.

5.3.- Processing, analysis and determination of the standard.

The processing, analysis and determination of the norm when the observations are made through the method of Individual Detailed Photography is carried out by summarizing the average data of the observations made to the worker and / or team studied, projecting the use of the working day and determine the standard of time and production.

According to the analysis carried out and the technical-organizational measures taken, it will be projected how the standard times will behave and, taking into account the average volume of work performed (Vt), the operating time per unit (To / u) will be calculated, the time norm (Nt) and the production norm (Np).

Further on, it is explained in detail how the standard times are projected and how to calculate the operating time per unit, the time standard and the production standard.

CHAPTER VI

COLLECTIVE DETAILED PHOTOGRAPHY METHOD

(COLLECTIVE CONTINUOUS OBSERVATION)

The Collective Detailed Photography Method consists of making a detailed description of all the activities carried out within the working day by the group of workers studied and measuring the duration of each of them, in order to know the use of the working day of the same. It is used when you want to study:

• The work of a group of workers who perform the same operation in their respective jobs. For example: in a paint shop where there are three workers painting the chairs that are produced in other departments.

• A brigade of workers that works on the same work object and it is not possible to define the part of it that each one performs. Example: a brigade composed of two painters and an assistant who is painting the facade of a building.

Observations are made with a watch with a second hand and a tablet or table to locate the modeling and make the annotations.

Although this method is much more agile than Individual Photography, it has the disadvantage of requiring great skill from the observer.

6.1.- Determination of the number of observations.

To determine the number of observations to be made, the same method will be used as for Individual Detailed Photography, that is, Formula No. 4 may be used.

When using the formula or the table, it must be taken into account that the mean value of the measured element (mean) must be taken as the average working time (TT) corresponding to the group of workers observed, obtained from an initial sample of three observations.

To find the rank (R), first, for each day observed, the daily average of the working time corresponding to the studied brigade will be determined. Later, the difference between the maximum and the minimum value will be found, which will be the range to use.

6.2.- Making the observations.

Observations by means of the Collective Detailed Photography method will be carried out by recording in detail all the activities carried out by the group of workers under study, as well as the time spent on them.

6.3.- Processing, analysis and determination of the standard.

The processing, analysis and determination of the norm when the observations are made by the method of Collective Detailed Photography is carried out by summarizing the average data of the observations made to a group of workers, projecting the use of the working day and determining the production and time standard.

In one column the breakdown of the time expenses that make up the working day and subsequently five sets of columns to summarize the average time observed (according to the breakdown of the working day) corresponding to each of the members of the brigade, as well as the projected time for such time expenses. The volume of work carried out by the brigade or by each worker (if possible its independent measurement) will also be recorded.

At the end of this section, the observed average times and the projected times corresponding to the brigade as a whole will be recorded, which will later be used to calculate the operating time per unit, the time norm and the production norm.

CHAPTER VII

TIMING OF OPERATIONS.

The method of timing operations consists of directly measuring, by means of a stopwatch, the time taken by the operation under study and knowing the breakdown of time expenditures in the working day corresponding to the job under study, reaching conclusions about the standard to implant.

In this method (as in all direct observation methods), special care must be taken when choosing the worker to be observed, following the guidelines generally given in Chapter III, Section 3.2. of this document

It is necessary to clarify that operation is understood as the part of the production process carried out by a worker in a given job and that covers all the actions to be carried out in compliance with a given work unit.

7.1.- Determination of the number of measurements to be carried out.

Due to the fact that the frequency distribution corresponding to the operating time is a normal distribution, to calculate the number of measurements to be carried out in a timing, we start from the expression corresponding to said distribution, which was used to calculate the number of photographs to be taken..

That is, we will start from Formula No. 3, which, as explained above, is used to calculate the number of measurements to be carried out based on the Range (R), the average value of the element measured (x - Operating time) and the factor d This depends on the size of the initial sample, when results with a confidence level of 95% and an accuracy of 5% are desired. So:

R2

N = 1600 ---- (3)

d2. x2

In the case of timing, it is recommended to perform an initial sample of 10 measurements, therefore the value of d, according to Table No. 1, is 3,078 (approximately 3). Therefore, substituting this value in Formula No. 3 we will have:

1600 R2

N = ---- (6)

9 x2

Where:

N = Number of measurements to be performed to obtain the average duration of the operation, with an accuracy of  5% and a confidence level of 95%.

x = Average duration of the operation (To / u - Operational Time / Unit), calculated from an initial sample of 10 observations.

R = Range of the initial sample, that is, the difference between the maximum value and the minimum value of the times measured.

Let's look at the following example:

Suppose that the previous timing performed to an operation (10 measurements) yielded the following data:

Substituting in Formula No. 6, we will have:

1600 (12) 2 1600 (144)

N = ---- = ----

9 (40) 2 9 (1600)

144

N = - = 16 measurements

9

Therefore, since 10 observations were initially made, 6 more would have to be made to complete the amount necessary to obtain an accuracy (s) of  5% and a confidence level of 95%.

7.2.- Carrying out the observation

Observations are carried out using the Operations Timing method, collecting the times that the operation carried out in a given job takes, measured by means of a stopwatch.

The timing of the start (HC) and end (HT) must also be taken into account for each of the series carried out.

At the end of the observation, the real time (TR) will be determined, which will be obtained by means of the difference between the end time (HT) and the start time (HC) of each series; as well as the timed time (TC), which will be given by the sum of the times of each of the measurements made.

These data will help us to determine, for each series, the Relative Error (ER) committed in the measurements, through Formula No 5 that appears in Section 5.2. of Chapter V. In the case of timing it is recommended that the Relative Error committed in each series be less than  1%. If greater, the series must be discarded and the timing repeated.

7.3.- Processing, analysis and determination of the standard.

The processing, analysis and determination of the norm when the observations are made through the Operations Timing method is carried out by summarizing the average data of the observations made to the operation under study and, once analyzed, determining the norm of time and production, based on the projection of how the working day should behave.

First, you have to sort the data in ascending or descending order, which will help us to appreciate their characteristics more precisely.

By ordering the data in this way, we can then determine their Range, which is expressed by the difference between the highest value and the lowest value.

The number of groups, classes or class intervals that should be used for grouping the data is immediately determined. The number of classes or groups of a given frequency distribution, it is recommended that they should not be so many that the harmony of a good distribution is lost, nor so few that this determines an agglomeration of the data that causes lack of distribution.

These groups or classes should not be, taking into account the opinion of various authors, less than 5 or greater than 18.

In order to facilitate the determination of the number of classes or groups in which the observed times should be grouped, the Table of Range Divisors that appears below (Table No. 3) can be used.

This table gives us, according to the number of measurements made, the approximate number of classes or groups into which the data can be divided.

Once the number of groups or classes has been determined, the amplitude of the class or the interval must be determined, understood as the difference between the numerical values ​​of their real limits, which must be the same for all classes.

To determine the Class or Interval Amplitude, the Range (obtained from the measurements made) must be divided by the Range Divisor (given by Table No.3).

Let's look at the following example:

Suppose that when timing the operation under study we have made 90 measurements and that the maximum and minimum values ​​are 231 sec. and 101 sec. respectively. The range of this data will be 130 sec. (231sec.-101sec.)

As in our example we have made 90 measurements, the Range Divisor, taking into account Table No. 3, is 12 and therefore we will have that the Amplitude of the class will be:

Class width = Range / DR = 130/12 = 10.8

Which is always rounded up to the highest odd number, and therefore the class width will be 11.

After calculating the width of the interval, we will proceed to construct the classes or groups, for which we will take the smallest number in the series, adding the width of the interval as many times as classes or groups we have to do.

Let's look at the following example:

In the case of the timing of the previous example, we have that since the shortest time is 101, we can start the first class or the first group at 101, this value constituting the lower limit of said class. The width of the interval will be added to this value and thus the first class 101-112 (101 + 11 = 112) will be achieved.

In the same way, the ends of each of the classes will be determined, always avoiding that the classes coincide at their ends, until reaching the classes that comprise the highest value, that is, the value of 231.

In our example, and taking into account the previous recommendations, the classes or groups in which the measurements will be divided will be:

To calculate the Production Norm and the Time Norm, it will be necessary to carry out a study prior to the job, either by Detailed Photography or by a Sampling by Instant Observations, in order to know the behavior of the different time expenses in that the Labor Day is broken down in order to be able to project standard times.

Frequency Histogram

The Frequency Histogram is the way to graphically present the Frequency Table and for this, two rectangular axes are made, representing the midpoints of the classes (in time units) on the abscissa axis (horizontal) and on the the ordinate (vertical) the frequency of the same.

7.4.- Analysis of the quality of the observations made

After completing the observations and before calculating the production and time norm, it is necessary to analyze their quality, to have the results as satisfactory or not depending on said analysis.

Graphical methods are widely used to check the quality of the observations, due to their simplicity. Among them are the creation of the Frequency Histogram, the Average Graph and the Range Graph.

Let's see below how they are made and how to analyze these graphs:

Frequency histogram

This graph should be made whenever a timing of no less than 25 measurements is made.

Its advantage is that it provides us with the possibility of visually detecting whether the distribution of the measured times belongs to a single population or to more than one, as well as whether times have been taken under normal or abnormal working conditions.

For its preparation, the midpoint of the classes into which we have divided the observed times is represented on the abscissa (horizontal) axis and the frequency, that is, the number of measurements that fall within each class (see Graph No. 1, in which some examples of Frequency Histogram appear.).

If we analyze Graph No. 1 we see that in Example A the Histogram extends to the right, which indicates that these extraordinarily high times must be motivated by abnormal issues in the workplace, such as: raw material out of the specifications (lowest quality); low voltage in the plant that slows down equipment; variations in the established method, etc.

These causes must be analyzed and measures taken for their eradication, thus eliminating excessively high times, timing again in order to reset the measurements and recalculating the mean.

In Example B the Histogram extends to the left indicating that the extremely short times are due to abnormal issues in the workplace, such as: raw material of better quality than usual; greater intensity of work; use of a more convenient working method; etc.

In this case, the conditions that caused the extremely low times must be analyzed and if it is possible to ensure that they continue to occur, re-time the operation after these new conditions have been implemented. If this is not possible, the small times will be eliminated, timed again in order to replace the discarded measurements and the average will be recalculated.

In Example C we observe that the Frequency Histogram has two modes, that is, two classes whose frequency is greater. This indicates that the series of data obtained belongs to two different populations, that is, that data that depend on another uncontrolled variable have been mixed, which in both cases has been different.

In this case, the cause that gave rise to this abnormality must be analyzed and time again taking into account it, that is, the previous operation will be timed as two independent operations.

Average Chart

This graph serves to know the statistical regularity of the measurements made, and should not be made with less than 25 measurements.

To make the graph, the data will first be grouped into n subsamples of 2, 3, or more consecutive values, according to the number of measurements performed.

Next, the mean (xi) and range (Ri) will be found for each of the groups, as well as the mean of the total sample (X mean) and the mean range (R mean) of the different groups.

Once these values ​​are obtained, they will be taken to a graph in which the values ​​of xi will be represented on the ordinate axis (vertical axis) and the abscissa axis (horizontal axis) will represent the reference number of the different groups.

Finally, the line representing the mean of the total sample (x) and the Control Limits, Upper and Lower, will be drawn.

To determine the Control Limits, the following expression will be used:

L1,2 = X mean  mean AR (7)

Where:

L1,2 = Upper (1) or Lower (2) Control Limit

X mean = Mean of the total sample (X mean =  xi / N)

A = Constant that depends on the size of the groupings made and whose values ​​appear in the Table No. 3

Mean R = Mean rank of the different groups (mean R =  Ri / N)

TABLE No 4

Sample size Constants to determine the Control Limits in the

Once the Control Limits have been determined, those measurements that fall outside these limits will be discarded, since they were made at a time when abnormal conditions existed.

Subsequently, as many measurements will be made as the quantity of them has been eliminated, proceeding again to calculate the mean and the control limits.

Let's see an example below:

In the timing of an operation, 40 measurements have been made, which appear below:

If we group the measurements into consecutive subsamples of size 2 and calculate the mean and range for each of them, we will have:

Let us now calculate the mean of the total sample, the mean range, and the control limits.

 Xi 3 032.5

X mean = --- = --– = 151.6 sec.

n 20

 Ri 567

R mean = --- = --– = 28.4 sec.

n 20

L 1,2 = X mean  AR mean

And as for a grouping in subsamples of size 2, the value of A (as indicated in Table No. 4) is 1.88, substituting we will have:

L 1.2 = 151.6  1.88 (28.4)

L 1.2 = 151.6  53.4

L 1 = 151.6 + 53.4 = 205.0 sec. (Upper limit)

L 1.2 = 151.6 - 53.4 = 98.2 sec. (Lower limit)

Finally, we plot the Xi values ​​of the subsamples formed in a coordinate axis graph and we draw the lines that represent the mean X and the Control Limits (Graph No. 6).

As can be seen in the graph, in this example the data corresponding to the 8th must be eliminated. observation day, since this point falls outside the control limits.

Range Chart

This graph is used to know the dispersion of the measurements made, and should not be made with less than 25 measurements. To make the graph, we will proceed, as in the previous case, to group the data into n subsamples of 2.3 or more consecutive values. Next, the rank (Ri) of each of the groupings and the mean rank (R mean) of the total sample will be found.

Once these values ​​are obtained, they will be taken to a graph, in which the values ​​of Ri will be represented on the ordinate axis (vertical) and the reference number of the different groups will be represented on the abscissa axis (horizontal).

Finally, the line that represents the average range (mean R) of the different groups and the Control Limits, Upper and Lower, will be drawn. To determine the Control Limits, the following expression will be used in this case.

L1,2 = DR (medium) (8)

Where:

L1,2 = Upper (1) or Lower (2) Control Limit

R (mean) = Mean range of the different groups (mean R =  Ri / N)

X (mean) = Mean of the total sample (x mean =  xi / N)

D = Constant that depends on the size of the groupings made and whose values ​​appear in Table No. 4

In column Ds the values ​​of D are offered to calculate the Upper Control Limit and in Column Di the values to calculate the Lower Control Limit.

As in the previous graph, after determining the Control Limits, those measurements that fall outside said limits are discarded, since they were at a time when abnormal conditions existed.

Subsequently, as many measurements will be carried out as the quantity of them has been eliminated, proceeding again to the calculation of the Average Range and the Control Limits.

Let's look at the following example:

Suppose that with the data from the previous example we want to make the Range Chart.

The mean range already calculated was 28.4 sec., And since the groupings were made in subsamples of size two, the values ​​of D, according to table No. 4, will be:

Ds = 3.27

Di = 0.01

Therefore, applying formula No.8 we will have:

L1 = Ds. R (Upper Limit)

L1 = 3.27 (28.4)

L1 = 92.9 sec.

L2 = Di. R (Lower Limit)

L2 = 0.01 (28.4)

L2 = 0.3 sec. (approximately zero)

CHAPTER VIII

ELEMENT TIMING

This method of determining the standard consists of measuring the time it takes for each of the elements that make up the operation under study and knowing the breakdown of the time expenses of the working day, corresponding to the given job, to reach conclusions about of the same.

It is necessary to clarify that by element is understood a certain set of actions that a worker performs to fulfill part of an operation.

8.1.- Division of the Operation in Elements.

In the subdivision of an operation into elements, it is very important to determine the cut points, that is, the moments where each of the elements in which we have divided the operation begins and ends.

Rigid guidelines cannot be given for the subdivision of an operation into elements, but general guidelines can be given, such as:

• It is convenient to subdivide the operation since this provides more information and greater precision in timing.

• This subdivision should not be so excessive that it prevents the regulator from following the performer in an orderly manner, nor should it be so scarce that he / she cannot have the necessary timing information.

• In each case, the optimal subdivision depends on the type of work and the data we want to obtain from the timing, as well as the experience of the regulator.

• It is recommended not to choose items with a duration shorter than 20 sec., Nor longer than 100 sec.

Let's look at the following example:

Suppose that the operation analyzed is to file a piece until it reaches the specified measurements and that the subdivision into elements carried out is as follows:

1. Take the piece, fix it, file and measure.

2. Drop it and put it down.

This subdivision is clearly of no practical interest, as it is very poorly detailed.

Another way to divide the operation could be:

1. Take the piece from the box.

2. Guide it by hand to the screw.

3. With another hand, tighten while holding the piece.

4. Take the file.

5. Bring the file to the piece, etc.

This is excessively detailed.

Another, more logical, would be:

Elements Description of elements

1. Fix the piece Take and put it on the screw

2. File Take the file, file, leave the file

3. Measure Take the caliper, measure, leave the caliper

4. Release the piece Loosen the screw and remove the piece.

As can be seen, each of these parts or elements have well-defined characteristics. They are useful, because taking into account the variables involved, the times obtained can be applied to elements of other operations, since they are sufficiently common elements.

8.2.- Determination of the number of observations

As in the timing of operations, determining the number of observations is an essential part of the preparatory stage in timing of items.

To determine the number of observations, an initial timing of 10 measurements will be carried out on each element, calculating with these data the mean (x) and the range (R) of each element.

Once these data have been obtained, the number of measurements that must be carried out to obtain the accuracy and the desired level of confidence will be calculated for each element, using Formula No. 6.

Once the total of necessary measurements has been determined, they will be carried out in 4 or 5 series of 10-20 measurements each, that is, the measurements should not be made at one time, but in different periods of time, in order to obtain most representative data.

It is recommended that measurements are not made during the first half hour of the day or during the last, since, as has been said, the work capacity of the worker in these periods is not adequate.

8.3.- Carrying out the observation

Observations are carried out using the Element Timing method by collecting the different times it takes for each of the elements that make up the operation carried out in a given job, measured by means of a stopwatch.

As many annotations will be made as measurements have to be made in a chronometric series to the elements that make up the operation studied.

The Start Time (HC) and the End Time (HT) of the timing will be entered, as well as the Real Time (TR) and the Timed Time (TC), data that will help us to determine the Relative Error (ER), using Formula No. 5.

When calculating the Relative Error of each series, the result should be less than  1%. In the event that it is greater, the timing must be repeated.

8.4.- Processing, analysis and determination of the standard.

The processing of the information obtained through the Timing of Elements is carried out in two parts. The first dedicated to obtaining the average time of each element and the second to obtaining the average time of the operation.

Initial processing

The initial processing dedicated to obtaining the duration time of each element is carried out by summarizing the Element Timing data and once they have been analyzed, determining the average duration of each of the elements that make up the operation.

Final processing

Once the average time of each of the elements that make up the operation studied has been found, it is necessary to determine the average time of the operation (Operating time per unit), (To / u) from the average times of the different elements that make up an operation, as well as the Production Standard and the Time Standard.

In the total, the sum of all the products will be entered, which will be equal to the average time of the operation studied or operating time per unit (To / u =  Fx).

Once the operating time per unit (To./u) has been determined, the Production Standard (Np) and the Time Standard (Nt) will be calculated.

Let's look at the following example:

Suppose that we want to determine the Operational Time per unit of the operation "Make packages containing 50 brochures" and that the elements that make up the cycle are:

A: Place 50 brochures on the table containing the wrapping paper.

B: Wrap and seal

C: Place the package on the "pallet"

These elements, due to the fact that they occur each time the operation of making a package is carried out, would have a frequency equal to unity (F = 1). However, during the execution of the task it was observed that other elements occurred, such as:

D: Remove the pallet. This work consists of removing the "Pallet" to the storage area. Starting from the basis that 60 packages can be placed on each pallet, this element will occur once every 60 times that cycle A, B, C occurs and therefore we have that the frequency of this element will be:

F = 1/60 = 0.0167

E: Replace the wrapping paper. This job consists of fetching large wrapping sheets when those on the table run out. During the timing it was observed that this element was given twice, and it was found that in the first opportunity the worker brought 46 envelopes and 50 in the second; so it was made clear that 50 sheets can be transported, and therefore, the frequency of the element will be:

F = 1/50 = 0.02

F: Change the rubber band. This job consists of changing the gummed paper roller. It is estimated that it lasts to seal about 500 packages, so the frequency of the elements will be:

F = 1/500 = 0.002

G: Supply water to the sealing equipment tank. It is estimated that it takes approximately to seal about 500 packages, so the frequency of this element will be:

F = 1/500 = 0.002

Summarizing:

Therefore:

To / u =  F. x = 66.1 sec.

8.5.- Analysis of the quality of the observation made

The quality analysis when carrying out a Timing of Elements is carried out by means of the preparation, for each element, of the Frequency Histogram, the Graph of Means and the Graph of Ranges, for which the guidelines that are offered for the quality analysis in Operations Timing.

CHAPTER IX

PROCEDURE FOR THE DETERMINATION OF THE STANDARDS

9.1- Elements that make up the Labor Standards:

When developing the work rules, it is essential to take into account all the time expenses necessary to carry out the task, as well as the regulated interruptions.

The elements that make up the standard, taking into account the structure of the working day that appears in chapter II, are the following:

TIME EXPENDITURE SYMBOL

Necessary work

time TTN Preparatory-conclusive

time TPC Operative time TO

Main time TP

Auxiliary time TA

Service

time TS Technical service

time TST Organizational service

time TSO Time of Regulatory Interruptions TIR

Rest Time and personal needs TDNP

Time Rest TD

Time of Personal Needs TNP

Time of interruptions determined by the Technology and Work Organization established TIRTO

9.2.- Determination of production and time standards

To calculate the production and time norm, we start from the operating time per unit of production determined by one of the study methods of time expenses and the projection made of the different time expenses that intervene in the norm (time of required work and regulated outage times).

Download the original file