Technological development and communications at accelerated levels and the ever increasing increase in demand and consumer expectations, where competition reaches higher levels, are some of the international market trends that particularly affect companies.
According to Arnoletto (2007), in an attempt to explain the current situation, he refers to the combined action of three concurrent factors: the new technology that manifests itself in an accelerated development of new products and services, of new processes and materials, with innovations that open surprising possibilities; globalization, which is expressed in the opening of markets, especially in the financial field, in an increasingly complex network of better communications and transportation and in increasingly large, complex and interactive organizations that are at the same time decentralized; and changes in expectations, which shortens the life of products and services and leads to a rapid obsolescence of almost everything, and consequently to a notable tightening of competition.
To adapt to unpredictable market conditions and rapid economic and technological changes, companies seek mechanisms that enable them to respond quickly and effectively to these demands. This responsiveness of our organizations is what defines them today as world-class companies.
According to several authors, these companies must have characteristics such as: zero defects, minimum manufacturing time, maximum use of highly qualified personnel, direct linkage of the product design with the production process, Total Quality management and continuous improvement of all processes, global management according to the principles of Just - in - Time and planning for the future.
In this framework, a new form of organization of production emerges called Cellular Manufacturing, which has its antecedents in the principles of group technology. Becoming this in the main link to achieve companies of this type.
The benefits of Cellular Manufacturing are multiple, however some difficulties that result from its application stand out, which must be taken into account, the main barrier being the necessary change of mentality, as it is a form of organization of production that it revolutionizes the old conceptions of production.
Cellular manufacturing is a subject little addressed by studies in our country, since it implies a number of challenges in its adoption as a manufacturing system, given by the conditions of the Cuban economy.
Hence, the objective of the research is to expose the fundamental ideas of what is understood by cellular manufacturing, as a form of organization of production. To comply with the objective, it was structured as follows: Introduction, Development and Conclusions; In the first part of the Development, the methods of organization of production are exposed, concluding on their main characteristics; followed by an analysis of the antecedents of Cellular Manufacturing, considering first the different definitions and then the fundamental elements to take into account for its implementation as a production system.
The main methods used were historical-logical and analysis-synthesis. The importance of the work lies in the fact that, from the bibliographic search carried out, it is possible to critically analyze cellular manufacturing, and its inclusion as a topic of discussion between economists and industrial engineers, for its implementation in Cuban companies, adapting it to our conditions. real.
DEVELOPING
Methods of organization of production.
From the systemic point of view, the company is made up of several subsystems; each of which has a particular purpose that guarantees, in its interrelations with the others, the operation of the same. For each subsystem a purpose and a set of plans is defined, which are articulated to form the business strategy, also responding to the definition of the mission and vision of the organization.
In the case of the operations or production subsystem, its mission is to obtain the goods and services that must satisfy the needs detected by the commercial subsystem and / or generated by the research and development subsystem. It also constitutes the core of the business system as it is in this where the process of transformation of inputs (inputs) into outputs (output) occurs, the latter with a greater added value.
Many are the authors who have dedicated themselves to studying the concept of production, each of them analyzing it from their own perspective. In the research of Companys & Corominas (1998) a series of concepts from different authors are collected:
The production process is the set of all the activities that are required to transform a set of inputs (human resources, raw materials, energy, etc.) into more valuable outputs such as finished products and / or services. (Dervitsiotis 1981)
Production is a fundamental function of the organization. It includes those activities responsible for the creation of goods and services that are the outputs or resulting from any organization. Production involves the design, planning, operation and control of the systems they produce. These systems are those processes or procedures that transform a set of inputs (the resources acquired by the organization) into outputs (the products that the organization sells or distributes). The inputs are some combination of humans, materials, money, machines, and methods (technology). The transformation can be physical as in manufacturing, locational as in transportation, temporary as in warehousing (stored) or transactional as in retail marketing. The outputs can be tangible,a good or a service, or simply satisfaction. (Tersine 1985)
For their part, these researchers conclude that production is the transformation of some goods and / or services into other goods and / or services. The latter are products and the former are factors of production; and this transformation is motivated by the fact that products are more useful than factors. (Companys and Corominas 1998)
All these definitions have several points of contact, and that is that production is a process of transformation of inputs of all kinds, the end result of which is a product of greater value, which guarantees precisely satisfy the needs and desires of consumers, to from the fulfillment of the client's specifications. This process also involves a series of decisions to be taken into account to guarantee the highest quality of the final product, in the shortest time and at the lowest possible cost.
In the business framework, when we refer to the operations strategy, we refer to a functional strategy whose objectives and plans must be combined with the others, in order to contribute to the achievement of the mission and vision of the organization. This is specified in a series of decisions to be taken by the management team of the company, and according to the operations strategy model developed by Hayes, Wheelwright and Clark in 1984 and 1988, respectively, they can be divided into structural and infrastructural. (ESADE 2004)
Structural decisions, also called hardware, have, in general terms, more continuity over time and are associated with a higher investment volume, these are defined as decisions of: capacity, location of production and logistics centers, process design and finally vertical integration and purchases. Infrastructure decisions, also called software, on the contrary, are the most powerful since they are based more on people and require less investment, these are those related to: human resources, quality, planning and control, organization, systems of measurement and control as well as the development of new products. (ESADE 2004)
One of these decisions that is of particular importance is related to the design of the process. It is preceded by the analysis of the product design and the capacity, since according to this will be the chosen process configuration, guaranteeing in turn the correspondence with the operations strategy. It is precisely through this decision that the company determines how the process of transforming inputs into outputs will be carried out. In the literature there are several classifications of productive configurations, proposed by different authors from their own perspective.
Woodward (1965) formulated a first classification that distinguishes between unit manufacturing, small batches, large batches, series production and continuous processes; The fundamental drawback of this classification lay in the delimitation of what is understood by small and large batches. (Domínguez, Álvarez et al. 1995)
On the other hand, in another investigation, taking into account the competitive priorities determined by the company, the nature of the product and the volume of production, five types of processes are defined: project, workshop, discontinuous process, assembly line and processing plant.
- Project or dispersed flow: They are usually processes of a single product and of great complexity that require a large number of inputs. These resources are supplied at the place where the product is manufactured, which does not vary during the production process. The sequence of operations and the process they form are unique to each project. Products require a custom design according to customer specifications. The coordination of activities and resources acquires a critical character. Manufacturing times are long and the skill level of the workforce is high. Flexibility understood as adaptation to design changes is very high. Workshop or disconnected irregular flow: These are processes designed for non-serial production in small batches and with single orders or in small quantities.Products move within the process Resources must be more flexible to cope with different designs. The choice of this production system implies that the organization basically competes in technological innovation and flexibility. The workforce has a high degree of specialization and the investment is directed to machinery for various uses. Discontinuous process or disconnected regular flow: As the demand for the workshop increases and the range of products decreases, production begins in product batches and the disconnected regular flow type process develops. There is a wide range of processes between the workshop and the assembly line that produce similar products, on a repetitive basis, usually in large batches and in which operations are divided into specialized groups,such as milling, turning and pressing (in an industrial company), or radiology, analysis and specialty plants (in a large hospital). In this production system, after having processed a batch of a product in a specific operation, the operation is prepared to produce a new batch corresponding to another product. The production routes are variable to make the same product. There are significant ongoing stocks, since some of the components that are part of the final product are manufactured in advance. Variety is achieved more by a final docking strategy for each order than by build-to-order. Quality and flexibility are the fundamental competitive priorities. Assembly line or connected linear flow:The in-line production process is justified when volumes are high enough to invest in facilities designed for processes with a fixed and balanced sequence of operations between the different workplaces. Materials move linearly from one operation to the next according to a fixed sequence, and little stock is kept between each operation. The investment is considerable in machinery and equipment. The degree of utilization of machinery and equipment is very high. The products are highly standardized and we work for a stock of finished product; current stock is low. The degree of qualification of the workforce is lower than in the previous processes. The top competitive priorities are service and cost. Processing plant or automated continuous flow:The production process is made up of a predetermined sequence of operations and the flow of materials is continuous and transferred from one operation to another through highly installations. In these installations, a few materials are transformed into a large quantity of finished products. Capital intensity is very high, and in many cases requires production throughout the day. The location of the factories is important, taking into account the high volumes of materials and finished products. The people involved in the process carry out the control and supervision. The top competitive priority is cost. (ESADE 2004)(ESADE 2004)(ESADE 2004)and in many cases it requires production throughout the day. The location of the factories is important, taking into account the high volumes of materials and finished products. The people involved in the process carry out the control and supervision. The top competitive priority is cost. (ESADE 2004)and in many cases it requires production throughout the day. The location of the factories is important, taking into account the high volumes of materials and finished products. The people involved in the process carry out the control and supervision. The top competitive priority is cost. (ESADE 2004)
From another perspective Domínguez, Álvarez et al. (1995) based on the continuity in obtaining the product, they perform the classification, and indicate three types of processes: projects, batches and continuous. By projects, when one or a few products are obtained with a long manufacturing period; by batches, when different products are obtained in the same facilities; and continues when the same product is always obtained in the same installation. They then point out that in turn the batch configuration can be presented in three different ways, giving rise to the classification proposed by Hayes and Wheelwriht in 1984, which distinguishes between the category of project, workshops or batch, online and continuous..
Following this classification, the configuration of projects is the one used for the elaboration of unique and complex services or products (for example: oil tankers, airplanes, highways, railways, etc.). Each time one of these goods or services is produced, the activities to be carried out to achieve it may vary, so usually all of them, including the support ones, are jointly controlled by a coordination team, paying special attention to the total duration of the project. This implies that the precedence relationships between tasks, the cost of the different partial durations, the costs of delays, etc., have to be determined. This control also deals with the allocation and reallocation of resources throughout the duration of the project.
In the case of the production batch configuration, it is one whose fundamental characteristic, which differentiates it from the others, is that multiple products are obtained in the same installation so that once the desired quantity is obtained for one of them, we proceed to adjust the facility or facilities and to process another batch of another product, continually repeating this sequence. However, depending on the size of the batches obtained, the variety and homogeneity of the products manufactured and the characteristics of the processes followed, other types of configurations can be found:
- Job-Shop configuration (work shop): more or less small batches are produced of a wide variety of products with little or no standardization (they are made to measure or with many personalized options), using equipment of little specialization which is usually grouped into workshops or work centers based on the function they perform; These teams are usually versatile and allow various operations to be carried out, so a wide variety of outputs can be achieved. Variable costs are relatively high due to low or very low automation, but in return, the initial investment is not high, which generates a low fixed cost. Work centers produce low or very low volumes of diverse outputs made from different materials and with the help of very different tools.In the industrial plant, different tasks may be being developed at a certain moment for different sizes of batches of different items, as the products are in different stages of their process and different quantities are manufactured, it is difficult to use a fixed schedule of use of the equipment, so programming work becomes especially important. Information management is essential, bottlenecks must be minimized by controlling queues and adequate scheduling and control in the very short term. In turn, within this type of configuration, two situations can be distinguished:As products are in different stages of their process and different quantities are manufactured, it is difficult to use a fixed schedule of equipment utilization, making scheduling work especially important. Information management is essential, bottlenecks must be minimized by controlling queues and adequate scheduling and control in the very short term. In turn, within this type of configuration, two situations can be distinguished:As products are in different stages of their process and different quantities are manufactured, it is difficult to use a fixed schedule of equipment utilization, making scheduling work especially important. Information management is essential, bottlenecks must be minimized by controlling queues and adequate scheduling and control in the very short term. In turn, within this type of configuration, two situations can be distinguished:bottlenecks should be minimized through queue control and proper scheduling and control in the very short term. In turn, within this type of configuration, two situations can be distinguished:bottlenecks should be minimized through queue control and proper scheduling and control in the very short term. In turn, within this type of configuration, two situations can be distinguished:
- Tailor-made or workshop configuration: in this case, the process of obtaining the product requires a small number of unspecialized operations, which are carried out by the same worker or by a group of them, who take charge of the entire obtaining process. of a specific order using the different work centers for the development of the different operations, the batch is usually of a few units of a product normally designed according to the client's requirements, so the variety is practically infinite. They are very flexible processes due to their little or no automation and their low homogeneity.Batch configuration: in this case the obtaining process requires more operations and these are more specialized,with which it is difficult for the same operator to master them all with acceptable efficiency. The work centers have to contain somewhat more sophisticated machinery focused on certain types of operations, which requires a greater investment in capital, although the automation of the processes is still low and good flexibility is maintained. Each worker dominates the operation of one or several work centers, in this way the operator assigned to a center performs only the operations of the items that are carried out in it. The batch arrives at the work center to undergo an operation, and when it is completed on all the units in the batch, it is transferred to the next work center that indicates its route, or if it is busy, to a warehouse waiting for it go free.The product usually has quite a few versions from which the customer can choose, so it is no longer "made to measure", giving a certain degree of standardization, although there will continue to be low repeatability of operations, the variety is large, but with certain limitations with respect to the previous case. In both cases, the problem of scheduling operations has the same essence, the orders have to go through the different work centers to undergo different operations, and when an order arrives at a work center, it may find it busy with another order. There is a priority among the orders marked by the delivery date committed to the customer, in addition to a sequence of operations that must be respected, and which is given by the route of the item.For this reason, it is no longer "made to measure", giving a certain degree of standardization, although there will continue to be a low repetitiveness of operations, the variety is large, but with certain limitations with respect to the previous case. In both cases, the problem of scheduling operations has the same essence, the orders have to go through the different work centers to undergo different operations, and when an order arrives at a work center, it may find it busy with another order. There is a priority among the orders marked by the delivery date committed to the customer, in addition to a sequence of operations that must be respected, and which is given by the route of the item.For this reason, it is no longer "made to measure", giving a certain degree of standardization, although there will continue to be a low repetitiveness of operations, the variety is large, but with certain limitations with respect to the previous case. In both cases, the problem of scheduling operations has the same essence, the orders have to go through the different work centers to undergo different operations, and when an order arrives at a work center, it may find it busy with another order. There is a priority among the orders marked by the delivery date committed to the customer, in addition to a sequence of operations that must be respected, and which is given by the route of the item.but with certain limitations with respect to the previous case. In both cases, the problem of scheduling operations has the same essence, the orders have to go through the different work centers to undergo different operations, and when an order arrives at a work center, it may find it busy with another order. There is a priority among the orders marked by the delivery date committed to the customer, in addition to a sequence of operations that must be respected, and which is given by the route of the item.but with certain limitations with respect to the previous case. In both cases, the problem of scheduling operations has the same essence, the orders have to go through the different work centers to undergo different operations, and when an order arrives at a work center, it may find it busy with another order. There is a priority among the orders marked by the delivery date committed to the customer, in addition to a sequence of operations that must be respected, and which is given by the route of the item.There is a priority among the orders marked by the delivery date committed to the customer, in addition to a sequence of operations that must be respected, and which is given by the route of the item.There is a priority among the orders marked by the delivery date committed to the customer, in addition to a sequence of operations that must be respected, and which is given by the route of the item.
- Online configurations: when it comes to large batches of few different but technically homogeneous products, using the same facilities. These are items whose process of obtaining in the work center requires a similar sequence of operations, although some of them could skip some that are not necessary, so these machines are arranged online, one after another. After a batch of one item is manufactured, the machines are adjusted and a batch of a different one is manufactured, and so on. In this case the machinery is much more specialized than in the previous ones, giving a high investment in capital as well as greater automation and homogeneity of the processes than in the job-shop. However, because they have to be adjustable to carry out very similar operations,but not exactly the same (so there is a medium or high repeatability), the equipment is still more versatile than in the continuous configuration. The specialization of the workers is also greater than in the job-shop, thanks to this lower variable costs are achieved than in the previous cases, although flexibility is lost. On the other hand, the amount of the investment is higher, which implies incurring higher fixed costs. In addition, these teams usually give rise to the appearance of preparation costs. It typically involves long-term product and process design and is worth the effort given the benefits of mass manufacturing, whereby economies of scale benefits can be realized.The specialization of the workers is also greater than in the job-shop, thanks to this lower variable costs are achieved than in the previous cases, although flexibility is lost. On the other hand, the amount of the investment is higher, which implies incurring higher fixed costs. In addition, these teams usually give rise to the appearance of preparation costs. It typically involves long-term product and process design and is worth the effort given the benefits of mass manufacturing, whereby economies of scale benefits can be realized.The specialization of the workers is also greater than in the job-shop, thanks to this lower variable costs are achieved than in the previous cases, although flexibility is lost. On the other hand, the amount of the investment is higher, which implies incurring higher fixed costs. In addition, these teams usually give rise to the appearance of preparation costs. It typically involves long-term product and process design and is worth the effort given the benefits of mass manufacturing, whereby economies of scale benefits can be realized.In addition, these teams usually give rise to the appearance of preparation costs. It typically involves long-term product and process design and is worth the effort given the benefits of mass manufacturing, whereby economies of scale benefits can be realized.In addition, these teams usually give rise to the appearance of preparation costs. It typically involves long-term product and process design and is worth the effort given the benefits of mass production, whereby economies of scale benefits can be realized.
In the continuous configuration: batch manufacturing is transformed into a continuous flow of production when idle and waiting times are eliminated, so that the same operations are always being executed, on the same machines, to obtain the same product, with a chain or online arrangement. Each machine and equipment are designed to always perform the same operation and prepared to automatically accept the work that is supplied by a preceding machine, which has also been specially designed to feed the machine that follows; operators always perform the same task for the same product. There is a sequential dependency in an integrated system, each task to be performed may be different but these and the way in which they will be executed must be considered simultaneously.The homogeneity of the process and the repeatability of the operations are high. Production stops are not usually incurred, in some cases, a process stop could cause serious damage to the machinery. The basic objectives are the improvement of the flow of materials and work, rapid completion of work and generation of added value. In these environments, each time a task is executed on an item, it goes to the next stage without having to wait for the task in question to be performed on all the units in its batch. In order for the flow of work and materials to be as fluid and smooth as possible, all the stations in the chain have to carry out one or more tasks that, together, have the same duration, and movements should not occur outside the line.Since a total balance of operations is pursued, any problem that may arise in one of the stages and cannot be solved within the time constraints will affect the process as a whole.
Of the classifications presented, the one proposed by Domínguez, Álvarez et al. (1995) is the most complete and the one most used by students of operations. In this, the particularities of the different types of configurations are clearly observed. Taking it as a reference, it is possible to summarize the main differences and similarities of the different types of configurations through the following aspects, in the table shown below:
Table 1: Comparative summary of the characteristics of each configuration.
| ASPECTS | Draft | Lots | Keep going | ||
| Job-Shop | Line | ||||
| Custom | Batch | ||||
| Product | Unique and complex services or products. | Production batch of small units custom-designed for the client. | Production batch. Product of several options where the client can choose. | Large batches of few different products. | A single product that requires a specific sequence of operations. |
| Fixed costs | High | Low | Relatively Low | High | High |
| Variable costs | High | High | Relatively high | Low | Low |
| Flexibility | high | high | Half | Low | Inflexible |
| Repeatability | There is not | Very low | Low | High average | high |
| Operations scheduling | Dissimilar | Dissimilar sequence | Dissimilar sequence | Similar sequence | Equal sequence of continuous operations |
| Homogeneity | Not | Very low | Low | Half | high |
| Inventories in processes | Low | Media | High | High | Low |
| Specialization of the operators | high | Low | Half | high | high |
| Control of operations | High control | Emphasize short-term control | Emphasize short-term control | High control | The system itself exercises self-control |
Source: Own elaboration.
Cellular manufacturing.
Within this framework, Cellular Manufacturing is a new form of organization of production that has become relevant in the last two decades due to the dissimilar benefits that come from its application. In general terms, it is proposed that this arises as a different form to the traditional floor plan distributions, becoming a hybrid of the online and continuous configuration. It has its antecedent in group technology, which is based on the principle that similar things can be produced in a similar way.
This different way of organizing production systems seeks to transfer the advantages of online distribution to distribution by processes, making it a distribution by type of products, which are determined according to the similarities of the manufactured parts (Medina, Cruz et al. al. 2010)
Group technology.
The first ideas related to group technology arose at the Leningrad University (USSR), with the work of Mitrofanov (1959), which shows in his research that if similar parts of the machine tool itself were processed, taking advantage of the same preparation, important benefits could be obtained, such as: savings in machinery preparation time, increased capacity of the same and decrease in the cost of tools. (Neighborhoods 2007)
However, it was not until 1969 in an International Seminar, held in the international center of Turin, Italy, that it was proposed to implement Group Technology as a production system (presented by FRE Durie, production manager of the electronic systems department of the company Ferranti Ltd, with the work "Group Technology applied to an electronic company"). (Neighborhoods 2007)
Group Technology can be defined as a management theory, which is based on the principle that similar things can be done in a similar way; In this context when talking about things, it includes product design, process planning, manufacturing, assembly and production control. (Askin and Standridge 1993)
The term "TG" group technology is used in relation to the physical arrangement, arrangement and location of machines in a manufacturing facility. (Tarango, Rodríguez et al. 2009)
Within the context of manufacturing, TG is also defined as a manufacturing philosophy, identifying similar parts and grouping them into families in order to take advantage of their similarities in design and manufacturing. (Mungwattana 2000)
Definition of Cellular Manufacturing
In this sense, Cellular Manufacturing is defined as an application of group technology in manufacturing, where the entire manufacturing system is converted into cells composed of a group of machines that process a family of products.
Barrios (2007) considers it as a practice in which equipment and workstations are arranged to facilitate the performance of small batches and a continuous flow of production.
From another point of view, it is a flexible connection of machines and operators in a work cell, to minimize waste and maximize productivity (Azarang).
Gamez (2012), for its part, considers Cellular Manufacturing as a mini-factory within the factory, which regulates its operating costs, delivery times and also manages its structure. This allows adapting to changes to respond to customer needs, which in turn enables the generation of profits.
From another perspective it is seen as a system in which a family of products is completed in dissimilar machines located close to each other, these with a team of operators who have multiple skills, are trained to carry out multiple tasks in the cell and that They are also fully responsible for its performance (Tubino 2007).
Mutingi & Onwubolu (2012) point out that in practice, the essence of the Cellular Manufacturing System is to decompose the manufacturing system into a manageable autonomous subsystem, called a manufacturing cell, such that it improves workplace control, material handling, tools and planning. They also refer that the process of decomposition into cells involves the identification of the family of parts with processes or attributes of similar designs, and of the machines, such that each family can be processed in a single cell.
Despite this being a relatively new field of research, there are important contributions to the definition of Cellular Manufacturing, although there is no particular definition that has been generalized, as each researcher has contributed their own ideas based on their conceptions. and interests. In general, they all start from the fact that cellular manufacturing is an application of the principle of group technology that similar things can be done in a similar way. It is an arrangement of dissimilar machines in a work cell that are responsible for producing a family of products, which causes greater interaction between operators, improves production planning and control and minimizes waste, as well as inventories in processes,increasing work productivity and profit generation.
Cellular Manufacturing as a production system.
The adoption of Cellular Manufacturing as a manufacturing system is a process that becomes difficult and complex insofar as it involves a series of decisions that impact the entire company; and it is also necessary to take into account a number of variables that impose dissimilar restrictions.
From the analysis of the cell manufacturing theory, certain similarities that it possesses with the cell theory from the biological point of view emerge. A cell constitutes (the biological theory), the morphological and functional unit of every living being. In fact, the cell is the smallest element that can be considered alive. The third postulate of the cell theory indicates that the vital functions of organisms occur within cells, or in their immediate environment, and are controlled by substances that they secrete. (Albert et.al 2004).
By referring then to the company as a living organism, it turns out that its essence is the system of operations, whose functioning depends, among others, on the organization of production. The company that implements the Cellular Manufacturing System is composed of several cells, therefore, its nucleus is in this case the manufacturing cell. If the cell is the fundamental unit of the company, it is vitally important to guarantee its operation, because of the quality of the cell outputs, that is, the family of products that are processed in it, and the efficiency with which it is obtained., will result in high levels of income and lower costs, which will translate into greater competitiveness, which will contribute to the prolongation of the life of the company.
In biological theory, each cell is an open system, which exchanges matter and energy with its environment. All vital functions occur in a cell, so that only one of them is enough to have a living being. Thus, the cell is the physiological unit of life. (Albert et.al 2004)
Similarly, manufacturing cells can be considered open systems that exchange information, resources and materials with their environment. These are determined by the types of inputs (inputs), which are transformed during the production process, to generate outputs (outps) that have a greater added value. According to the type of input, they will be the specifications of the output; the types of inputs determine the specificities of the final product. Usually the inputs to the system are energy, materials, labor, capital, and information.
Cells are prepared to respond to attacks from foreign bodies to the body. Therefore, it is necessary to look for mechanisms that ensure the existence of flexible cells, which easily and quickly adapt to the changing demands and pressures of the environment.
In biological theory, cell structures determine its functionality, that is, cells differ in size and shape; there are elongated cells, such as muscle fibers or cells with fine extensions, such as neurons that transmit nerve impulses. Similarly, the manufacturing cells fulfill certain functions depending on their structures and characteristics, which in turn obey the elements that make it up, that is, the machine tools. The type of machine and tools, the quantity and their arrangement in the cell will determine the functionality and complexity of the cell.
Kaebernick a & Bazargan-Lari, (1996) and Mahdavi & Mahadevan (2008), handle the idea that in general when talking about the design of the Cellular Manufacturing System, it includes three critical decisions, called: cell formation, cell distribution cells and planning; and in the ideal case, to obtain the best possible results these three aspects should be recorded simultaneously. (Mutingi and Onwubolu 2012)
For their part, Mutingi & Onwubolu (2012) understand that the entire design process of the Cellular Manufacturing System involves four generic phases: cell formation, design group, planning group and available resources. In relation to cell formation this involves machines that can operate a family of products with little or no intercellular movement of the products. The layout group includes the layout of the machines within each of the cells (intra-cell layout) and the layout of the cells with respect to one another (inter-cell layout). The planning group involves the planning of parts for production. Finally, the availability of resources refers to the allocation of tools, manpower, materials and other resources.
In the case of the design of manufacturing cells, one of the objectives pursued is to minimize the movements and exchange of material between the cells, since this is associated with a cost and a certain time that influences the efficiency of the system. This objective is achieved if cells are generated that guarantee the complete manufacture of the assigned products (Medina, Cruz et al. 2010). However, in most cases this is not possible due to the complexity of the production systems.
There are several ways to face the problem, one is to assume that there will be parts that visit more than one cell in their manufacture, another is to replicate the machine that must be visited by several parts of different cells, in each of the cells that is needed; These and the other solutions that can be given to the problem require an in-depth analysis, since they imply a cost, therefore the person responsible for the formation of the cells must submit to consideration the one that is more beneficial to the organization.
Similarly, in the cell formation and design problem, other objectives are pursued, such as: minimizing movements within the cell itself, maximizing utilization, minimizing the cost of handling materials and the balance of workload.. (Mutingi and Onwubolu 2012).
There are several works in the literature that address the problem of the design of manufacturing cells from different points of view, although at the beginning they only referred to the arrangement of the machines inside the cells, more recently there have been investigations that address the problem both the intra- and inter-cellular layout, highlighting the genetic and metaheuristic algorithms of artificial intelligence and programming as techniques and methods used.
When talking about cellular manufacturing, its advantages are many and varied. They increase productivity and quality. Cells simplify material flow, management, and even charting. (Oca 2008)
In this sense Singh (1996) in a few words defines and describes the advantages of Cellular Manufacturing, when he concludes that conceptually it is a mixture between the distributions by process and product and are based on the philosophy of group technology. This type of configuration is also appropriate for manufacturing systems with a diversity of products and variable production volumes. It generates advantages in issues such as process times, setups, material handling, furniture, required space and increases job satisfaction and quality. (Mejía 2012).
Later in his research, Oca (2008), from another point of view, analyzes the advantages of cellular manufacturing when he states that: it reduces the handling of the largest piece, employs highly trained operators, frequent changes can occur in the product, it adapts to a great variety of products, greater flexibility and, lastly, it points out as one of the most important, the possibility of increasing or decreasing the number of workers required when it is necessary to adapt to changes in demand. However, these advantages are focused only on those cells whose layout is in a U, without addressing the advantages in a general way and considering other forms of arrangement (straight line, serpentine, the U and the inverted U) within the cells.
Other authors with respect to this comment, for example López (1997), that one of the main benefits of this manufacturing system is that it offers the opportunity to combine the efficiency of the production system per line with the effectiveness of functional distribution or by processes.
Mungwattana (2000) for his part in his research addresses in a more detailed way the benefits of Cellular Manufacturing, in the sense that it enables the reduction of:
- Set-up times: Manufacturing cells are designed to handle parts that have similar shapes and relatively equivalent sizes. For this reason, many of the parties use similar tools. Generic accessories for part families must be designed so that the time required to change these accessories and tools decreases. Lot of smaller parts: once the preparation time in the cell is very small, they are possible and cheaper, the smallest batches; at the same time, these make it possible to regulate the flow of production. The existence of finished products and processes: taking advantage of the above advantages, it is possible to reduce inventories. In this case it refers to the work of Askin and Standridge,which obtain as a result that the products in processes can be reduced by 50%, when the preparation times are reduced by half. Likewise, if preparation times and inventories are achieved in smaller processes, this contributes to the reduction of the inventory of finished products. Contrary to traditional manufacturing systems in this, the production of the parts requires the use of just-in-time for those small batches or small fixed-time intervals.The times and costs of material handling: in cellular manufacturing each part is processed completely in the same cell, or at least as much as possible. Therefore, part of the travel time and the distance between cells is minimal. Time flow: shorter material handling and preparation times reduce it.Tool requirements: the parts produced in a cell are similar in shape, size and composition; in this way, they frequently require similar tools Space requirements: reduction of inventories in processes and finished products as well as batch size, requires less space Waiting time: in the batch production system the parts are moved between machines in groups. However in Cellular Manufacturing each part is immediately transferred to the next machine after being processed. In this way the waiting time is substantially reduced. And it also refers to the improvements and increases reported by Cellular Manufacturing, in aspects such as:in this way, they frequently require similar tools Space requirements: reduction of inventories in processes and finished products as well as batch size, requires less space Waiting time: in the batch production system the parts are moved between machines in groups. However in Cellular Manufacturing each part is immediately transferred to the next machine after being processed. In this way the waiting time is substantially reduced. And it also refers to the improvements and increases reported by Cellular Manufacturing, in aspects such as:in this way, they frequently require similar tools Space requirements: reduction of inventories in processes and finished products as well as batch size, requires less space Waiting time: in the batch production system the parts are moved between machines in groups. However in Cellular Manufacturing each part is immediately transferred to the next machine after being processed. In this way the waiting time is substantially reduced. And it also refers to the improvements and increases reported by Cellular Manufacturing, in aspects such as:In the batch production system the parts are moved between the machines in groups. However in Cellular Manufacturing each part is immediately transferred to the next machine after being processed. In this way the waiting time is substantially reduced. And it also refers to the improvements and increases reported by Cellular Manufacturing, in aspects such as:In the batch production system the parts are moved between the machines in groups. However in Cellular Manufacturing each part is immediately transferred to the next machine after being processed. In this way the waiting time is substantially reduced. And it also refers to the improvements and increases reported by Cellular Manufacturing, in aspects such as:
- The quality of the product: the parts travel from one station to another as a single unit and they are completely processed in a small area; This makes it easy for feedback to be carried out immediately and processes can be stopped if a problem is detected. Control of all operations: the fact that each part passes through a single cell facilitates planning and control.
Seen from another point of view, the benefits that cells provide can be summarized in the following ideas: shorter lead times, continuous improvements, reduced recycling, quality improvements, reduction of inventory in process at the plant, simplified control, less space used, simplified scheduling, less material hauling, smaller batches, simpler management, job enrichment, facilitates new ideas and decision making. (Tubino 2007)
Likewise, other authors refer to the benefits of Cellular Manufacturing within the framework of Lean Manufacturing, pointing out that it: improves communications due to the proximity of some operators to others within the cell; stimulates communication and cooperation between workers as there are no departmental barriers or walls; quality is improved through improved communications within the cell itself, through the flow of parts; cellular distribution leads to having multifunctional operators; encourages flexibility and reduces capital costs; the labor force is enriched; the control of the plant is simpler. (Eguizabal, Melara et al. 2006)
It is important to note that at first glance, cellular manufacturing may seem simple, however, underneath this deceptive simplicity there are sophisticated Socio-Technical systems. Its proper functioning depends on subtle interactions of people and equipment. Each element must fit with the others in a running, self-regulating and self-improving operation. (Oca 2008)
Many challenges must be considered when implementing cells, especially those related to resistance to change and the new organizational demands imposed by this new form of organization of production. Under these conditions, it is necessary to have operators trained to carry out multiple activities within a cell, which implies high training costs; Another challenge lies in the high obsolescence costs that would result if the market for single cell products were to collapse. In the same way, others can be mentioned, such as: the costs resulting from “forced stops” tend to be higher; other products will have to wait, even when there are idle resources in the cell; resources should not be used for alternative tasks, in a workshop,products can be assembled in the first resource vacated; and in a workshop, resources can be devoted to alternative products more easily.
CONCLUSIONS
Cellular Manufacturing has its antecedents in Cluster Technology, specifically in the principle that similar things can be done similarly; it constitutes a new form of organization of production that synthesizes the advantages of the online configuration and continues.
The adoption of this as a production system implies a series of decisions related to the grouping of the family of parts and the formation of cells, cell distribution (inter-intra), and production planning; seeing these as the three major fundamental decision groups; because around each one of them interact a number of variables to take into account, such as those related to the implementation process of the cells, with regard to human resources in quality and quantity, financial resources, tool and material management system that reaches a new dimension, and other organizational demands. It is also important to consider the aspects related to the evaluation of the performance of the cells, from the economic and technological point of view.
Its advantages are multiple and range from the reduction of manufacturing preparation and waiting times, to the reduction of inventories in processes and finished products, also they reduce the requirements of tools and space, and increase the quality of the products. and control of all operations.
In addition, the aforementioned disadvantages must be considered, assessing in each case the cost of each of them with respect to the possible benefits to be obtained.
The simple fact of organizing production based on cells does not guarantee obtaining these benefits, as it is a process that impacts the entire organization.
Cellular Manufacturing is a way to achieve world-class companies as the aforementioned advantages are the representation of the characteristics of said organizations. That is why a detailed study of each of the aforementioned aspects is essential, in order to achieve the competitiveness of the modern company in the face of the changing demands of the environment.
BIBLIOGRAPHY
- Alberts et al (2004). Molecular biology of the cell. Barcelona: Omega. ISBN 54-282-1351-8Arnoletto, EJ: (2007) Production management as a competitive advantage, Free electronic edition. Retrieved September 5, 2014 from www.eumed.net/libros/2007b/299/Askin, RG and CR Standridge (1993). Group Technology - Cellular Manufacturing. Modeling & Analysis Of Manufacturing Systems, John Wiley & Sons.Azarang, MR Celdas de Manufactura. Retrieved on November 14, 2014 from http: //lean.mty.itesm.mx Barrios, VMC (2007). Study for the implantation of a manufacturing cell in the metal mechanical industry.. Mexico DF, National Polytechnic Institute. Engineer. Companys, R. and A. Corominas (1998). Organization of production I. Design of production systems 1, UPC.Domínguez, JA, MJ Álvarez, et al. (nineteen ninety five). Operations management. Strategic aspects in production and services.. Sevilla, McGraw-Hill. Domínguez, JA, MJ Álvarez, et al. (nineteen ninety five). Operations management. Statistical and operational aspects in production and services. Sevilla, McGraw-Hill. Eguizabal, J., E. Melara, et al. (2006). Applications of Lean Manufacturing in Salvadoran Industry. Faculty of Engineering and ArchitectureSan Salvador Central American University José Simeón Cañas. Industrial Engineer, Department of Operations and Innovation Management at ESADE (2004). Innovation management guide. Production and logistics.. Catalonia, Spain.: AuthorGamez, M. (2012) What is cellular manufacturing. Retrieved on November 14, 2014 from http: // manufacturacelualr.mty.itesm.mx Heragu, S., G. Meng, et al. (2001) Analysis of cellular manufacturing systems. Retrieved on November 14 from www.math.utwente.nl/publicationsJob, J. and VM Pillai (2010) Performance Evaluation of Adaptive Cellular Manufacturing System using Simulation López, LMA (1997). Design and Implementation of Cellular Manufacturing in a Job Shop Environment. Department of Mechanical Engineering. Massachusetts, Massachusetts Institute of Technology. Master of Business Administration and Master of Science in Mechanical Engineering. Medina, PD, EA Cruz, et al. (2010). "Generation of manufacturing cells using the Binary Ordering algorithm (AOB)." Scientia et Technica. Mejía, C. (2012). Model for defining the layout of a manufacturing cell through optimization. Department of Mechanical and Mechatronics Engineering. Bogotá, National University of Colombia. Magister in Mechanical Engineering Metternich, J., S. Bechtloff, et al. (2013) Efficiency and Economic Evaluation of Cellular Manufacturing to enable Lean Machining. Mungwattana, A. (2000). Design of Cellular Manufacturing Systems for Dynamic and Uncertain Production Requirements with Presence of Routing Flexibility. Faculty of the Virginia Polytechnic Institute and State University. Virginia, State University. Doctor of Philosophy in Industrial and Systems Engineering.Mutingi, M. and GC Onwubolu (2012). Integrated Cellular Manufacturing System Design and Layout Using Group Genetic Algorithms. Manufacturing System, InTech. Retrieved November 20, 2014 from http://www.intechopen.com/books/manufacturing-system/integratedcellular manufacturing-system-design-and-layout-using-group-genetic-algorithms Oca, IJPMD (2008). Project to increase productivity with the Design of manufacturing cells in the area of Capacitors in a metalworking company Instituto Politécnico Nacional México DF Master of Science in Industrial Engineering Ram, R. and N. Viswanadham (1992). «Performance evaluation of cellular flexible manufacturing systems: A decomposition approach.. » European Journal of Operational Research 57: 287-304. Rodríguez, G., A. Meneses, et al. (2007) Dynamic analysis of the behavior of a metal parts manufacturing cell Seidmann, A., P. Schweitzer, et al. (1985). "Performance evaluation of a flexible manufacturing cell with random multiproduct feedback flow." 23. Serrano, A. and A. Suárez (2004). Analysis and evaluation of the general elements of the Lean Manufacturing theory that can generate development in a company in the plastics transformation sector. Case of UPR Ltda. Industrial Department. Bogotá, Pontificia Universidad Javeriana. Industrial Engineer Shouman, M., G. Nawara, et al. (1999) Evaluation of cellular manufacturing systems in the presence of machine interruptions.Tarango, LE, MA Rodríguez, et al. (2009) Optimization of a cellular manufacturing system. 2nd International Research Congress Tubino, F. (2007) Cellular manufacturing. Under a QRM philosophy.
