Introduction times and movements
Through the study of times and movements, the standard times of each of the operations that make up a process can be determined, as well as the movements that the operator makes to carry out the operation can be analyzed. This avoids unnecessary movements that only increase the operation time.
The study of times and movements allows to detect operations that are causing delays in production and improve the efficiency of the line. Within the study of times and movements, the environmental conditions are also taken into account, since these influence the performance of the operators. Maintaining good environmental conditions is necessary to reduce fatigue.
The quality must be maintained in each operation to avoid waste of time in reprocessing the finished product.
History
It was in France in the 18th century, with the studies carried out by Perronet about the manufacture of pins, when the study of times in the company began, but it was not until the end of the 19th century, with Taylor's proposals that it spread and he knew this technique, the father of the scientific administration began to study the times at the beginning of the 80's, there he developed the concept of the "task", in which he proposed that the administration should be in charge of planning the work of each of its employees and that each job had to have a time standard based on the work of a highly qualified operator. After a time, it was the Gilbreth couple who, based on Taylor's studies, would expand this work and develop the study of movements,dividing the work into 17 fundamental movements called Therbligs (his last name backwards).
Frederick W. Taylor is generally considered to be the father of the modern time study in the United States, although in fact time studies were already done in Europe many years before Taylor. In 1760, a Frenchman, Perronet, carried out extensive time studies on the manufacture of common No. 6 pins up to the standard of 494 pieces per hour.
Taylor began her time study work in 1881 when she worked at the Midvale Steel Company in Philadelphia. After 12 years he developed a System based on the concept of "task". In it, Taylor proposed that:
- The management of a company should be responsible for planning the work of each employee at least one day in advance. Each man should receive detailed written instructions that describe his task in detail and also indicate the means he should use to carry it out. The job had to have a standard time that was based on the job possibilities of a highly qualified operator. In the process of setting times, he recommended dividing the work into small portions called “elements”.
In June 1903, at the ASME meeting held in Saratoga, Taylor presented his famous article "Shop Management", in which he outlined the foundations of Scientific Management. To mention some points the following:
- The Study of times, together with the implements and methods to carry it out properly. The Standardization of all the tools and implements used in the factory. The Standardization of actions or movements of the workers for each class of work. Instructions cards for the employee.
Study of times
The study of times is a technique used to determine the standard time allowed in which an activity will be carried out, taking into account the personal delays, fatigue and delays that may occur when carrying out said activity. The time studies analyst has several techniques that are used to establish a standard: chronometric study of times, standard data, fundamental movement data, work sampling, and estimates based on historical data. Time study seeks to produce more in less time and improve efficiency at workstations.
Movement study
The study of movements consists of analyzing in detail the movements of the body when carrying out an activity with the aim of eliminating ineffective movements and facilitating the task. This study is combined with the study of times to obtain better results regarding the efficiency and speed with which the task is carried out. The study of movements can be applied in two ways, the visual study of movements and the study of micro movements. The first is applied more frequently due to its greater simplicity and lower cost, the second is only feasible when highly active tasks whose duration and repetition are high are analyzed. Within the study of movements we must highlight the fundamental movements, these movements were defined by the Gilbreth spouses and are called Therblig's,there are 17 and each one is identified with a graphic symbol, a color and a letter O ACRONYM:
- SEARCH B Black SELECT SE Light gray TAKE OR ASSIR T Red REACH Olive green MOVE M Green HOLD SO Gold Soltar SL Carmine PLACE IN POSITION P Blue PRECOLLAR IN POSITION PP Sky blue INSPECT IRE DREAM Light Purple YELLOW DURSELY DURING Purple Coffee DESCANSAR DES Naranja
Principles of motion economy
Human ability to perform tasks depends on the type of strength, the muscle used in the task, and the person's posture when performing the task. That is why the work must be designed according to the physical capabilities of the individual to achieve better performance in carrying out the work.
There are three basic principles:
Those related to the use of the human body, those related to the disposition and conditions in the workplace, and those related to the design of the equipment and tools.
These movements are divided into efficient and inefficient like this:
Efficient or effective
Physical or muscular in nature: reach, move, release and pre-position. Objective or concrete in nature: use, assemble and disassemble.
Inefficient or ineffective
Mental or semi-mental: search, select, position, inspect and plan.
Delays or delays: avoidable delay, inevitable delay, rest and hold.
goals
From the study of times
Minimize the time required for the execution of works. Conserve resources and minimize costs.
Carry out production without losing sight of the availability of energy or energy.
Provide a product that is increasingly reliable and of high quality.
From the study of movements
Eliminate or reduce inefficient movements and accelerate efficient ones. Excerpted from The Principles of Movement Economics.
An industrial operation can be defined as an area of the process or equipment where materials, inputs or raw materials are incorporated and a certain function occurs, they are basic activities that are part of the process.
It would be practically impossible to study the almost infinite number of chemical processes that are carried out in the industry on a daily basis, if there were not one point in common to all of them. Fortunately this connection exists. Any process that can be designed consists of a series of physical and chemical operations that in some cases are specific to the process under consideration, but in others, are common and equal operations for various processes.
Another definition
"Industrial operations is any chemical process conducted on any scale that can be broken down into an ordered series of what could be called UNIT OPERATIONS, such as spraying, drying, crystallization, filtration, evaporation, distillation, etc. The number of these basic operations is not very large and generally a few of them intervene in a certain process ”. This concept was introduced in 1915 by Professor Little of the Massachusetts Institute of Technology (MIT)
Thus, for the classification of unit or industrial operations, the property that predominates in a transformation is taken into account. Based on this, the classification is made into two large groups:
Physical unit or industrial operations
- Matter transfer Energy transfer Simultaneous matter and energy transfer Momentum transfer Complementary
In all unit or industrial operations the driving force concept is in common. The amount of property transferred per unit of time and area is equal to the split driving force of the resistance.
Unit operations are physical in nature. They can be divided into 5 large groups:
- Fluid flow Heat transfer Mixing Separation: Distillation, extraction, absorption, adsorption, evaporation, crystallization, humidification, drying, filtration and centrifugation Solids handling: Compression, grinding, sieving and fluidization. There is no clear division between some operations. The operation of a continuous evaporator requires knowledge of fluid flow, heat transfer; likewise crystallization, as in obtaining the hydrosulfite, can occur in evaporation, etc.
Chemical industrial or unit operations
Its objective is to distribute the atoms of one molecule in a different way to give another, the passage of reagents to products. It occurs in chemical reactors; For the design of these, these characteristics must be studied:
Unit processes are classified according to the type of chemical reaction involved. In 1945, in his text "The Chemical Process Industries" Professor RN Shreve classified the main unit processes as follows:
- CombustionOxidationNeutralizationSilicate formationCausticizationElectrolysisDouble DecompositionCalcinationNitrationEsterificationReductionAmonolysisHalogenationSulfonationHydrolysisHydrogenationReaction of Friedei-CraftsCondensationPolymerizationFermentationDiasotization and couplingPyrolysisAromatization
These have similarities and disparities with each other, but the similarities are apparent and cannot be treated in a generic way as is done with unit operations.
The steps necessary to systematically carry out work measurement are:
To select:
The work to be studied.
To register:
All the data related to the circumstances in which the work is carried out, the methods and the elements of activity that they entail.
Examine:
The recorded data and the detail of the elements with critical sense to verify if the most effective methods and movements are used, and to separate the unproductive or strange elements from the productive ones.
To size:
The amount of work for each element, expressed in time, using the most appropriate work measurement technique.
Compile:
The standard time of the operation providing, in case of study of times with a stopwatch, supplements for short breaks, personal needs, etc.
Define:
Accurately the series of activities and the method of operation to which the computed time corresponds and notify that this will be the standard time for the specified activities and methods.
Advantage
Study of times and movements and logistics operations
- Minimize the time required for the execution of works. Conserve resources and minimize costs. Effect production without losing sight of the availability of energy resources. Provide a product that is increasingly reliable and of high quality. Eliminate or reduce movements inefficient and accelerate efficient. Distribution of workloads. Integral management of waste and residues within the process.
Disadvantages
- This system is not common for all companies. It is used in more than twelve different systems. To achieve the highest credibility percentage, continuous practice is necessary.
conclusion
Standardizing time is in order to have a basis for scheduling work, determine standard labor costs, and hence sustain incentives for staff.
The analysis of a process can lead to redesign actions to increase efficiency, reduce costs, improve quality and shorten times by reducing production and delivery times for the product or service.
Bibliography
- Albert Ibarz and Gustavo V. (2005) "unit operations in food engineering". Printed in Spain. Pág. 29-30.Martha Orozco (1995) “Unitary operations. Editorial LIMUSA SA P. 8-13
