3.0 Plant Layout Types.pptx

plant layouts

1. Based of the type of Industry, production quantity and production variety, following are the major plant layout types: P ro c e ss Layout P ro d u c t Layout F i x e d - p o s i t i o n Layout C o m b i n a t i o n a l Layout C e ll u l a r Layout 1

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3. In this type of layout, all machines (and other equipment) for performing similar/same operations are grouped at one location e.g. all lathes are grouped in one shop, all the drill machines at another shop and so on. Therefore, we can say that there are different shops (or areas) in this type of a plant each dedicated to provide a different process or function. Machines are not arranged as per the operation sequence of any product. Any product that requires all or some of the available processes in the plant can be manufactured using this plant layout. Process layout is also known as Functional Layout or Job-shop layout. 3

4. Suitable for production of different products in batches. It is characterized by low to medium variety and small to intermediate production volume. G r e a t e r f l e x i b i l i t y w i t h r eg a r d t o w o r k d i s t r i b u t i o n t o m a c h i n e r y a n d personnel. Adapted to frequent changes in sequence of operations. Lower investment due to general purpose machines; which usually are less costly than special purpose machines. Higher utilization of production facilities; which can be adapted to a variety of products. Variety of jobs makes the work challenging and interesting. Breakdown of one machine does not result in complete stoppage of work. It can be easily handled by transferring work to another machine/work station. I t off e r s b e tt e r a n d m o r e e ff i c i e n t s u p e rv i s i o n t h ro u g h s p e c i a l i z a t i o n a t various levels. 4

5. Backtracking and long movements occur in handling of materials. As such, material handling costs are higher. Total production cycle time is more owing to long distances and waiting at various points. Since more work is in queue and waiting for further operation hence bottle necks occur. Mechanization of material handling is highly challenging (not possible in many cases) and expensive. Production planning and control is difficult. It is difficult to achieve good labour and equipment balance. More space requirement; as work-in-progress inventory is high-requiring greater storage space. As the work has to pass through different departments; it is quite difficult to fix the responsibility for the finished product. Specialization creates monotony and there will be difficult for the laid workers to find job in other industries.  It is difficult to undertake adequate time and motion studies. 5

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7. All the processing equipment and machines are arranged according to the sequence of operations of the product In this type of layout, only one product of one type of products is produced in an operating area. This product is standardized and produced in large quantities. It is also called line layout or flow layout because machines are arrange in a line. The raw material is supplied at one end of the line and goes from one operation to the next quite rapidly with a minimum work in process, storage and material handling. The finished product is taken out at the other end of the line. Special purpose machines are used to perform required operations at different workstations. 7

8. R e d u c e d m a t e r i a l h a n d l i n g c o s t d u e t o m e c h a n i z e d h an d l i n g s y s t e m s a n d straight flow Perfect line balancing which eliminates bottlenecks and idle capacity. Short manufacturing cycle due to uninterrupted flow of materials and therefore, total production time is also minimized. Simplified production planning and control; and simple and effective inspection of work. Small amount of work-in-progress inventory Lesser wage cost, as unskilled workers can learn and manage production. Time and motion studies can be done to determine the rate of work. 8 G oo d b a l a n c e o f l a b o u r an d e q u i p m e n t e x i s t s a n d t h e r e f or e utilization is achievable. Minimum of inspection is required, during sequence of operations. Minimum of set-ups are required. t h e r e b e tt e r

9. L a c k of f l e x i b i l i t y o f o p e r a t i o ns , a s l a y o u t c a nn o t b e a d a p t e d to t h e manufacture of any other type of product. Large capital investment, because of special purpose machines. Any breakdown of one machine in the sequence may result in stoppage of production. Same machines duplicated for manufacture of different products; may lead to high overall operational costs. Delicate special purpose machines require costly maintenance/repairs. The manufacturing cost increases with a fall in volume of production. Specialized and strict supervision is essential. 9

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12. In this type of layout the major component remain in a fixed location, other materials, parts, tools, machinery, man power and other supporting equipment’s are brought to this location. It is also called stationary layout or static layout . Ship-building, air-craft manufacturing, wagon building, heavy construction of dams, bridges, buildings etc. are typical examples of such layout. 12

13. Material movement is reduced. Capital investment is minimized. The task is usually done by gang of operators, hence continuity of operations is ensured Production centers are independent of each other. Hence, effective planning and loading can be made. Thus total production cost will be reduced. It offers greater flexibility and allows change in product design, product mix and production volume. 13

14. Highly skilled man power is required. M o v e m e n t of m a c h i n e s e q u i p m e n t ’ s consuming. 14 t o p ro d u c t i o n c e n t e r m a y b e t i m e Complicated fixtures may be required for positioning of jobs and tools. This may increase the cost of production. It require complicated work schedule.

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16. In practice, plants are rarely laid out either in product or process layout form. Generally a combination of the two basic layouts is employed to derive the advantages of both systems of layout. For example, refrigerator manufacturing uses a combination layout. Combination of two types of layouts may occur in different forms: Most of the manufacturing sections are arranged in process layout with manufacturing lines occurring here and there (scattered) wherever the conditions permit. Machinery is arranged in a process layout but the process grouping (a group of number of similar machines) is then arranged in a sequence to manufacture various types and sizes of products. Process layout is used for producing components and thereafter the final assembled product is manufactured on an assembly line (a product layout). It is also known as combined layout or hybrid layout. 16

17. In a typical factory, process layout is used to produce various operations like stamping, welding, heat treatment being carried out in different work centers as per requirement. The final assembly of the product is done in a product type layout. In case when the same product varies in size and type but the sequence of operations remain same or similar, similar machines are grouped in departments and departments are arranged in a product layout format. As illustrated in the given diagram for gear manufacturing. A combination layout is also useful when a number of items are produced in same sequence but none of the items are to be produced in bulk and thus no item justifies for an individual and independent production line. For example, files, hacksaws, circular metal saws, wood saws, etc. can be manufactured on a combination type of layout. 17

18. Group Technology (GT): It is a management philosophy of dividing items/objects/things into groups (also called families) on the basis of similarities of their attributes. Cellular layout applies the principle of group technology to manufacturing to take advantage of similarities in products grouped in a family. This technique is very useful for companies that produce large variety of parts in small batches. To enable them to take advantage of economics of flow line layout, a process layout can be redesigned into a cellular layout. In this layout, all products are grouped in families on the basis of their manufacturing attributes each family is assigned a cell for its manufacturing whereby the operations required are provided in a line layout. 18

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20. Cellular manufacturing brings scattered processes together to form short, focused paths in concentrated physical space. So constructed, by logic a cell reduces flow time, flow distance, floor space, inventory, handling, scheduling transactions, and scrap and rework (the latter because of quick discovery of nonconformities). Cells lead to simplified, higher validity costing, since the costs of producing items are contained within the cell rather than scattered. Cellular manufacturing facilitates both production and quality control. Cells that are underperforming in either volume or quality can be easily isolated and targeted for improvement. The segmentation of the production process allows problems to be easily located and it is more clear which parts are affected by the problem. The small cell structure improves group cohesiveness and scales the manufacturing process down to a more manageable level for the workers. Workers can more easily see problems or possible improvements within their own cells and tend to be more self-motivated to propose changes 2 2

21. Group Technology layout can increase Component standardization and rationalization. Reliability of estimates. Effective machine operation and productivity. Customer service. It can decrease the Paper work and overall production time. Work-in-progress and work movement. Overall cost. 2 3

22. High Cost: The cost of implementation is generally high. This is because an outside consultant is often required since in house expertise on GT is rarely available. It requires a long set up time and painful debugging. Not Suitable for large Variety of Products : May not be suitable for a factory with a very large variety of products. The entire production of the company cannot be put under the GT and hence GT will have to coexist with the conventional layouts. Not suits all Applications : There are too many GT codes in use and there is no one GT code that suits all applications. It is often difficult to conceive all the operations for a group of components being taken care of in the cell created for it. The range of product mix in a plant many be under constant change in which case the GT cells may need constant revision which is impractical . This type of layout may not be feasible for all situations. If the product mix is completely dissimilar, then we may not have meaningful cell formation. 2 4