Facility Design and LayoutHenry C. CoTechnology and Operations Management,California Polytechnic and State University
Facility Design and Layout (Henry C. Co)2Facility Design Facility layout: Arrangement of machines,storage areas, and/or work areas usuallywithin the confines of a physical structure,such as a retail store, an office, awarehouse, or a manufacturing facility. Factors that influence layout Volume, weight of items to be produced. Nature of the service to be provided. Cost of the building to house the operation. The product mix that must have a facility. The fragility of the product or component.
Facility Design and Layout (Henry C. Co)3A Good Layout ... Reduces bottlenecks in moving people ormaterial. Minimizes materials-handling costs. Reduces hazards to personnel. Utilizes labor efficiently. Increases morale. Utilizes available space effectively andefficiently. Provides flexibility. Provides ease of supervision. Facilitates coordination and face-to-facecommunication where appropriate.
Facility Design and Layout (Henry C. Co)4Flow-Line Layout Applicable to both manufacturing and nonmanufacturing operations. Arrange machines and/or workers inaccordance with the sequence of operationsfor a given product or service. Advantages of flow-line layout Reduces materials handling. Accommodates small amounts of work in process. Reduces transit times. Simplifies production planning and controlsystems. Simplifies tasks, enabling unskilled workers tolearn task quickly.
Facility Design and Layout (Henry C. Co)5 Disadvantages of flow-line layout Lack of process flexibility. Lack of flexibility in timing: the product can notflow through the line faster than the slowest taskcan be accomplished unless that task is performedat several stations. Large investments: special-purpose equipmentand duplication is required to offset lack offlexibility in timing. Dependence of the whole on each part: abreakdown of one machine or absence of enoughoperators to staff all work stations may stop theentire line. Worker fatigue: workers may become bored bythe endless repetition of simple tasks.
Facility Design and Layout (Henry C. Co)6Process Layout Grouping together of machines and/orworkers doing similar tasks. Applicable to both manufacturing and nonmanufacturing operations. Advantages Flexibility: equipment and personnel can be usedwhere they are needed. Smaller investment in equipment: duplication isnot necessary unless volume is large. Expertise: supervisors for each departmentbecome highly. knowledgeable about theirfunctions Diversity of tasks: changing work assignmentsmake work more satisfying for people who prefervariety.
Facility Design and Layout (Henry C. Co)7 Disadvantages Lack of process efficiency: backtracking and longmovements may occur in the handling ofmaterials. Lack of efficiency in timing: workers must waitbetween tasks. Complication of production planning and control. Cost: workers must have broad skills and must bepaid higher wages than assembly line workers. Lowered productivity: because each job isdifferent it requires different setups and operatortraining.
Facility Design and Layout (Henry C. Co)8Fixed Position Layout Manufacturing and non-manufacturingoperations of bulky or fragile products, e.g.,ships and planes. Move machines and/or workers to the site;products normally remains in one locationfor its entire manufacturing period. Advantages of fixed position layout Reduces movement of work items; minimizesdamage or cost of moving. More continuity of the assigned work force (sincethe item does not go from one department toanother). This reduces the problems of re-planning and instructing people each time a newtype of activity is to begin.
Facility Design and Layout (Henry C. Co)9 Disadvantages of fixed position layout Since the same workers are involved in moreoperations, skilled and versatile workers arerequired. The necessary combination of skills maybe difficult to find and high pay levels may benecessary. Movement of people and equipment to and fromthe work site may be expensive. Equipment utilization may be low because theequipment may be left at a location where it willbe needed again in a few days rather than movedto another location where it would be productive.
Facility Design and Layout (Henry C. Co)10Group Technology Layout Definition of Group Technology“Group technology is the technique ofidentifying and bringing togetherrelated or similar parts in a productionprocess in order to utilize the inherenteconomy of flow production methods.”V. B. Solaja,Institute of Machine Tools, Belgrade, Yugoslavia
Facility Design and Layout (Henry C. Co)11 Group Technology layout is also calledmanufacturing cell layout. Example: A plant producing 10,000 part numbers may beable to group the parts into 50 or 60 families.Each family would possess similar design andmanufacturing characteristics. Hence, the processing of each member of a givenfamily would be similar, and this results inmanufacturing efficiencies in the form of: Reduced set-up, Lower in-process inventories, Better scheduling, Improved tool control, Standard process plan.
Facility Design and Layout (Henry C. Co)12Concept Many problems are similar, by groupingsimilar problems, a single solution can befound to a set of problems, thus saving timeand effort. A manufacturing philosophy in which similarparts are identified and grouped together totake advantage of their similarities in designand manufacturing. A technique for identifying and bringingtogether related or similar components inorder to take advantage of their similaritiesin the production process.
Facility Design and Layout (Henry C. Co)13Concept Design ManufacturingMany problems aresimilarSimilar Shapes SimilarManufacturingProcessesGroup SimilarProblemsDesign Families Production FamilySingle Solution ofProblemsOne standard designplus minormodificationOne standardprocess plan to afamily andmodification andextension
Facility Design and Layout (Henry C. Co)14Manufacturing Cell Cellular manufacturing is the physical division of themanufacturing facilities into production cells. Each cell is designed to produce a part family. A part family isa set of parts that require similar machinery, tooling, machineoperations, and/or jigs and fixtures. The parts within the family normally go from raw material tofinished parts within a single cell. Justification Batch production Only 5% of the lead time in producing a part is direct workingtime; 95% of the time, the part is waiting. The 5% direct working time includes 30% actual processing and70% for positioning, chucking, gauging, etc. Hence, only 1.5% is accounted for actual machining. Cellular manufacturing directs its effort towards the remaining98.5% by organizing the plant layout according to work cell,rather than functions. A work cell is a unit that includes all ofthe machines required to produce a family of parts.
Facility Design and Layout (Henry C. Co)15Advantages/Disadvantages Advantages Implied reduction of necessary control Reduced material handling Reduced set-up time Reduced tooling Reduced in-process inventory Reduced expediting Increase operator expertise Improved human relations.
Facility Design and Layout (Henry C. Co)16 Disadvantages Reduced shop flexibility Possible reduced machine utilization Possible extended job flow times Possible increased job tardiness. Implementation Issues Reorganization - machine layout needreorganization every so often. Work cell supervision - supervisors must be expertin several field (milling, turning, grinding, etc.)represented in the cell. Shop floor control / production planning - cellconcept leads to unbalanced workload onmachines.
Facility Design and Layout (Henry C. Co)17Analysis of Layout By Process Steps involved:1. Determine the size of each department.2. Determine the arrangement of thedepartment with respect to one another.3. Determine the arrangement of theequipment and people within eachdepartment.
Facility Design and Layout (Henry C. Co)18Closeness Rating DefinitionA Absolutely necessaryE Essentially importantI ImportantO Ordinary closenessU UnimportantU UndesirableAnalysis of Layout By Process Richard Muthers Systematic LayoutPlanning Utilizes a grid matrix to display the ratingsof the relative importance of the distancebetween department Closeness ratings:
Facility Design and Layout (Henry C. Co)19Distance Measurements Typically measured from department centerto department center. Euclidean distances are appropriate whenthe layout space is very open and movementwithin it can follow a direct path. Rectilinear (sometimes called rectangular)distance is more appropriate for layoutsaisles or hallways where one generallyreaches a destination after making one ormore right turns.
Facility Design and Layout (Henry C. Co)20Load Distance Analysis Each department is 10 feet by 10 feet,distances are rectilinear, which of thefollowing two layouts is better?Layout A Layout B3 87 41 109 26 54 710 12 95 68 3
Facility Design and Layout (Henry C. Co)23Solution (1/2) Compute the total travel for eachproduct through each layoutalternative.ProductDepartmentProcessingSequenceDistance perProduct (feet)Layout ADistance perProduct (feet)Layout B (feet)A 1→5→4→10 30+30+10= 70 30+30+10= 70B 2→6→3→9 20+40+30= 90 20+10+10= 50C 2→10→1→9 10+10+10= 30 10+10+10= 30D 1→7→8→10 10+20+20= 50 10+50+30= 90E 2→5→6→9 10+10+10= 30 10+10+10= 30F 1→7→4→10 10+10+10= 30 10+10+10= 30
Facility Design and Layout (Henry C. Co)24Solution (2/2) Compute total distance traveled permonth by each product through eachlayout alternative.Units per Distance per Product Distance per MonthProduct Month Layout A Layout B Layout A Layout BA 1000 70 70 70,000 70,000B 2000 90 50 180,000 100,000C 3000 30 30 90,000 90,000D 1000 50 90 50,000 90,000E 2000 30 30 60,000 60,000F 4000 30 30 120,000 120,000Totals 570,000 530,000*
Facility Design and Layout (Henry C. Co)25Computer Packages Heuristic, improvement algorithms. CRAFT (Computerized Relative Allocation of FacilitiesTechniques) is the best known of the heuristicsapproaches; attempts to minimize materials-handlingcost by calculating cost, pair-wise interchangingdepartments, calculating more costs until a goodsolution is obtained. ALDEP (Automated Layout Design Program) andCORELAP (Computerized Relationship LayoutPlanning) attempt to maximize a nearness ratingwithin the facility dimension constraints. PREP (Plant Re-layout and Evaluation Package)analyzes multilevel structures and is based on actualfootage traveled by materials-handling equipment.