In order to meet the goals of good layout according to the annual product requirements and product types, the layouts are divided into four major categories, namely, fixed or position layout, line or product layout, process or function layout, and combination or group layout. Each type of layouts is explained with the respective merits, demerits and application as below.
1. Fixed or positional layout
Fixed or positional layout is also known as project layout. A typical fixed layout is shown in Fig. 2.1. This type of layout keeps most of an assembly or material in a fixed position. All supplies, auxiliary material, machines, necessary equipment, necessary tools and manpower are brought to the fixed location for work. Thus the product stays in one place due to its bulk density. Therefore, the location of the main assembly, semi-assembly component and material will not be disturbed until the product is ready to ship. This arrangement is suitable when one or a few parts of an article are to be manufactured and the material forming or machining operation requires only tooling or simple machinery. This layout is very preferable when the cost of moving the main piece of material is high and responsibility for product quality is expected from a skilled worker or group of skilled workers. This type of layout is mainly used for extremely large items that are manufactured in very small quantities, such as ships, airplanes, boilers, reactors, etc. The main benefit of this layout is the minimal movement of people, materials, and tools during the manufacturing process. This layout is highly flexible as the nature of the product and related processes can be easily changed without changing the layout. The pros and cons of this type of layout are given below.
Its main advantages are—
1. The layout is highly flexible for product variants with intermittent needs, as the type of product and related processes can be easily changed without changing the layout.
2. There is minimal movement of people, materials and tools during the manufacturing process.
3. The material is drastically reduced.
4. Highly skilled operators are required to complete the work at one point, and quality responsibility rests with one person or assembly team.
5. Each person of the manufacturing team is responsible for the quality work in manufacturing the product.
The main disadvantages of this layout are
1. Equipment handling costs are very high.
2. Manpower and equipment are difficult to fully utilize.
3. It is only limited to large items.
This type of layout is mainly used for extremely large items that are manufactured in very small quantities, such as ships, airplanes, airplanes, locomotives, ship assembly shops, shipyards, boilers, reactors, etc.
2. Process or function layout
A typical process or function layout is shown in Fig. 2.2. With this type of layout arrangement of similar machines, production plants and manufacturing companies, they are grouped according to their functions. Machine tools of one type are positioned together so that all similar operations are always performed in the same place, e.g. All lathes can be grouped together for all types of turning and threading, all drilling machines in one area to perform drilling, all tapping machines in one area to perform threading, all milling machines in one area to perform milling, all buffing and polishing machines in one Place to carry out surface finishing work and so on. This type of layout is typically preferred for industries involved in custom manufacturing and manufacturing and/or maintenance activities of a non-recurring nature. This layout does not have to be changed with every product or component change. Even the failure of a machine does not affect production. This type of layout is very suitable for series production.
The main advantages of this layout are:
1. There is great flexibility in assigning work to equipment and workers.
2. There is better use of available equipment.
3. This layout requires a comparatively smaller number of machines, thereby reducing capital investment.
4. There is improved product quality as supervisors and workers take care of some kind of machines and operations.
5. Different jobs appearing as different work orders make work more interesting for workers.
6. Workers in one section are not affected by the nature of the work being carried out in another section. For example, a lathe will not be affected by the welding jets since the two sections are fairly separate.
The main disadvantages of this layout are:
1. This layout requires more space compared to the line or product layout with the same production volume.
2. Production control becomes relatively difficult with this layout.
3. Raw material needs to be transported more, which increases material handling and associated costs.
4. This layout requires more efficient coordination and inspections.
5. Increased material handling costs due to increased movement of process raw material through various routes
6. Other in-progress material remains in the queue for further operations.
7. Requires large in-process inventory.
8. It takes longer time to complete the same product.
1. This layout is used for batch or moderate production.
2. It indicates the path for the group technology.
3. Line or product layout
A typical line or product layout is shown in Fig. 2.3. This arrangement implies that different operations on the raw material are carried out one after the other and the machines are arranged along the product flow line, i. H. the machines are arranged in the order in which the raw material is processed. With this type of arrangement, all the machines are arranged in a line according to this sequence of operations, i. H. each succeeding machine or section is arranged to perform the next operation to that performed by its preceding machine or section. In this layout, raw material begins at one end of the production lines and moves along a sequential path from one machine to the next. The line layout is advantageous in the continuous production system when the number of end products is small and the parts are highly standardized and interchangeable. It is suitable for products with steady demand. This layout may have an operational sequence of forging, turning, drilling, milling, grinding and testing before the product is sent to the finished goods warehouse for packing and shipping. This layout is used for mass production and ensures smooth material flow and reduced material handling. The failure of a machine in the line in this layout can even lead to a production stop.
Its main advantages are—
1. It involves a smooth and continuous workflow.
2. It may require less skilled labor
3. It helps in reducing inventory.
4. Production time is reduced in this layout.
5. Better coordination, easy production planning and control are achieved in this layout.
6. With the same production volume, less space is required for this layout.
7. The total processing time of the product is very short.
8. This layout involves automatic material handling, less material movement and therefore results in the minimum possible manufacturing cost.
The main disadvantages of this layout compared to the process layout are:
1. It is very difficult to scale up production beyond the capacity of the production lines.
2. If a single inspector has to take care of many machines, the inspection becomes difficult
3. This layout is very inflexible for product changes.
4. The working speed or speed depends on the output speed of the slowest machine, and therefore will cause excessive idle time for other machines if the production line is not adequately balanced.
5. Machines placed along the line, more machines of each type need to be installed to keep a few on standby because if one machine in the line breaks down it can bring the entire production line to a standstill. For this reason, the line or product layout involves high capital investments.
It is used in assembly work.
4. Combination layout
Fig. 2.4 shows a typical combination arrangement for producing different crankshaft sizes. It is also known as group layout. A combination of process and product layout combines the advantages of both types of layout. Most manufacturing sections are arranged in a process layout, with manufacturing lines appearing scattered here and there wherever conditions permit. Today, most manufacturing industries have adopted this type of layout. In this type of layout, a set of machines or equipment is grouped into a section, etc., so that each set or group of machines or equipment is used to perform similar operations to make a family of components. A combination layout is
possible if an item is produced in different types and sizes. In such cases, machines and manufacturing equipment are arranged in a process layout, but a group of similar machines are then arranged in a sequence to produce different types and sizes of products. With this layout, it should be noted that regardless of whether the product varies in size and type, the sequence of operations remains the same or similar. This layout is appropriate when similar activities are performed together, avoiding wasting time switching from one independent activity to the next. It focuses on avoiding unnecessary duplication. It is preferable to store and retrieve information that changes in relation to recurring problems, reducing the search for understanding information and eliminating the need to solve the problem again. It is also useful when multiple items are to be manufactured in the same sequence, but none of the items are intended to be manufactured in large quantities and thus no item warrants a single and independent production line. There are some advantages, disadvantages and applications of this layout which are listed as follows:
The advantages of this type of layout are:
1. Reducing the cost of machine set-up time and material handling of metals.
2. Elimination of excess inventory of work in progress, which subsequently allows lot size reduction.
3. Simplification of production planning functions etc.
The main disadvantages of this layout are:
1. Changing the existing layout is time consuming and costly.
2. Adding new components to the existing component requires thorough analysis.
3. Changing the mix of input components can probably change the whole layout structure.
4. A batch size change may change the number of machines.
Production of metal circular saws, metal saws, wood saws, files and crankshafts.
Reference Introduction to basic crafting processes and workshop technology by Rajender Singh.
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