END 202 Work analysis and design

Transcription

1 END 202 Work Analysis and Design (Mostly from M.P. Groover s book.) SibelALUMUR ALEV February 2011

2 Definition Facility layout refers to the size and shape of a facility as well as the relative locations and shapes of functional areas, departments, equipment, workstations, storage spaces, aisles, common areas in it. Facility layout includes all types of facilities: plants, warehouses, distribution centers, office buildings, hospitals, Plant layout is focused on production plants

3 Facility layout The layout of a facility is an important factor in determining the overall efficiency and effectiveness of the production or service operations A poor layout can result in inefficient work flows, unhappy workers, unsafe working conditions, and less capacity to carry out the operational mission of the facility

4 Facility layout A well designed layout should satisfy the following objectives: Efficient movement of materials and people Logical work flow and minimum travel distances between operations Efficient utilization of space Safety and satisfaction of workers and others who use the facility Flexibility to meet changing gfuture requirements Advancing the operational mission of the facility

5 Outline Types of production plant layouts Other typesof layouts Systematic layout planning

6 Types of plant layouts Why are there different types of production layouts? There are different types of production 2 important factors to distinguish types of production 1. Production quantity (Q): the number of units of a given product that the facility produces annually Low production (1 100 units/year) Medium production (100 10,000 units/year) High production (more than 10,000 units/year) 2. Product variety (P): dff different product designs or types that are produced (shape, size, style, function)

7 Relationship btw Q & P Relationship between production quantity (Q) and product variety (P)

8 Types of plant layouts There are 4 basic types of plant layouts: 1. Product (straight line) )layout 2. Process (functional) layout 3. Fixed position layout 4. Hybrid layouts combination of the above (These layouts are commonly associated with production plants and therefore referred to as plant layouts)

9 1. Product (straight line) layout High annual quantity, low product variety Workstations and equipments are located along the line of flow of the work units The work units are typically moved along the flowline line by a powered conveyor A small amount of the total work is accomplished at each workstation It is widely used in the production lines and assembly lines Examples:?

10 1. Product (straight line) layout

11 2. Product (straight line) layout Advantages High degree of efficiency and proficiency Specialized equipment and tooling can be developed to reduce cycletime High production rates Disadvantages Significant investment and high cost (Risk: If actual demand is less than anticipated when the plant was built) Cannot be easily adapted to produce a different product The equipments can become obsolete when the customer demand changes Major revisions and investments may be required to change over the plant for a new model

12 2. Process (functional) layout Low and medium production quantities, medium and high product variety Equipments are arranged according to function There is no common work flow path through the plant Different parts or products are processed with different operation sequences Examples:?

13 2. Process (functional) layout

14 2. Process (functional) layout Advantages Very flexible and versatile: deals with different operations, different parts and products The equipments are of general purpose and can be adapted for different products Workforce: skilled workers who are well paid Disadvantages Each part type is transported t dfrom one operation to the next: High material handling cost and high work in process inventory Disadvantage of versatility: low efficiency because of the change of setups

15 3. Fixed position layout Low product quantity, high product variety The product remains in one location in the plant during its whole fabrication (large and heavy products) The equipments and the workers are brought to the product Component parts are often manufactured elsewhere and brought for final assembly Examples: Railway locomotives, heavy machinery, gas turbines, steam engines

16 3. Fixed position layout

17 4. Hybrid layouts 2 basic types of hybrid layouts: 4.1 Cellular layout: tries to combine the best features of process and product layouts 4.2 Combinations of fixed position layouts and process or product layouts

18 4.1 Cellular layouts Cellular manufacturing: workstations and equipments are configured into cells consisting of several workstations Workstations are configured and tooled to make families of similar parts or products No drastic changes of setup Group technology is used (Similar parts or products are indentified and grouped together to take advantage of their similarities in design and production) More efficient than process layout and more versatile than product layout.

19 4.2 Combination of fixed position and process or product layout Large products are not built all at one location Shipyards Combination of fixed position and process layouts Each module is produced and then welded to other modules at a single location in the welding department Aircraft Combination of fixed position and product layouts Ex: Boeing plant in Washington producing models

20 Types of plant layouts Types of plant layout used for different levels of production quantity (Q) and product variety (P)

21 Outline Types of production plant layouts Other typesof layouts Systematic layout planning

22 Other types of layouts There are additional layout types for operations other than production Warehouse layouts Project layouts Service facility layouts Office layouts

23 Warehouse layouts Warehouse is a facility for storing merchandise, commodities or other items 4 main warehouse functions 1. Receiving i 2. Storing 3. Order picking 4. Shipping

24 Warehouse layouts Where to locate receiving and shipping i functions? Shouldthe two functions be combined at one location or separated?

25 Warehouse layouts Advantages of centralizing at one location Sharing of personnel and material handling equipment Sharing of docks and docking space (for example: if more vehicles arrive for shipping than receiving at a time) Facilitating cross docking: immediate transfer of received materialsto to shipping without t any storage Advantages of decentralizing (separating) Reduced congestion in the dock areas Reduced risk of confusing incoming loads with outgoing materials The layout can be designed to provide a flow through of materials, from receiving to storage to shipping

26 Project layouts Usually applies to construction projects The product of the project stays (the building) but the workers and the equipments move The layout is temporary and depends on the project size and needs Similar to fixed position layout Basic difference?

27 Service facility layouts Each type of service has its own layout requirements Most are based on process layout Example: Department stores Usually, the goal is to minimize the distances traveled dby paperwork (information) and people (workers, customers, etc.) In retail merchandising: the goal is to maximize the exposure of customers to the items, maximum exhibition Aesthetics: The general appearance and ambiance of a service facility must be pleasant

28 Office layouts Similar to process layout: Personnel are typically grouped according to their functions or departments Each department has its own area The closeness between different departments are important Theflow of work between departments should be used to decide their locations Noisemaking or dangerous departments are located away

29 Office layouts New trend: open office concept Consists of large open areas in which modular furniture and partitions rather than permanent walls are used to designate and separate workstations Advantages Lower construction costs Easier supervision of employees Flexibility for changes in the layout Better control of heating, cooling, lighting Improved communications among employees Disadvantages?

30 Outline Types of production plant layouts Other typesof layouts Systematic layout planning

31 Plant layout designs Levels of detail in plant layout designs Site layout Block layout Workstation layout Detailed layout

32 Systematic Layout Planning, SLP An approach to plant layout design developed by Richard Muther (1973) There are other approaches but this is the most widely used Most applicable to process layouts Most appropriate for designing a new plant The goal is to locate two areas with high frequency and logical relationship close to one another using straightforward procedure

33 Systematic Layout Planning, SLP Steps (A. Freivalds): 1. Chart relationships 2. Establish space requirements 3. Activity relationships diagram 4. Layout space relationships 5. Evaluate alternativearrangementsarrangements 6. Select layout and install Example: Plant layout of Dorben Consulting (pg 113)

34 Systematic Layout Planning, SLP Steps (M.P. Groover): 1. Determine requirements and collect data 2. Analyze material flows 3. Define activity relationships and develop activity relationship chart 4. Construct tactivity it relationship lti diagram 5. Determine the space requirements 6. Construct space relationship diagram 7. Make adjustments, add allowances 8. Develop block layout 9. Develop detailed layout

35 Systematic Layout Planning, SLP Steps (END 308: Tompkins, White, Bozerand Tanchoco): 1. Flow of materials 2. Activity relationships 3. Relationship diagram 4. Space requirements 5. Space available 6. Space relationship diagram 7. Modifying considerations 8. Practical limitations 9. Develop layout alternatives 10. Evaluation To be discussed in END 308: Facilities Planning and Design

36 How to develop layout alternatives Exact methods (modeling the problem as a MIP and solving exactly) usually limited Heuristics, meta heuristics (genetic algorithms, simulated annealing, ant colony, etc.) Commercially available optimization software based on heuristics (CRAFT, CORELAP, ALDEP) Virtual reality environment Other software (FactoryPLAN, FactoryFLOW, FLOW FactoryCAD)