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23 Cards in this Set
- Front
- Back
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What does "layout" refer to in facility layout?
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Layout refers to the configuration of
departments, work centers, and equipment, with particular emphasis on movement of work (customers or materials) through the system |
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What is the Importance of Layout Decisions
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Requires substantial investments of
money and effort Involves long-term commitments long Has significant impact on cost and efficiency of short-term operations |
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What causes The Need for Layout Designs
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-changes in the environment or other legal requirements
- changes in volume of output or mix of products - changes in methods or equipment -moral problems |
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what are the Inputs to the Layout Decision
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1. Specification of objectives of the system in terms
of output and flexibility. 2. Estimation of product or service demand on the system. 3. Processing requirements in terms of number of operations and amount of flow between departments and work centers. 4. Space requirements for the elements in the layout. 5. Space availability within the facility itself. |
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what are the Basic Types of Layout
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Process (Functional) Layout
Product Layout Group Technology (Cellular Layout) Fixed-Position Layout Hybrid or Combination Layout |
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What factors might we consider when
determining the locations of process areas, or departments? |
Given
The flow (number of moves) to and from all departments The cost of moving from one department to another The existing or planned physical layout of the plant Determine The “best” locations for each department, where best means interdepartmental transportation, or flow, costs |
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Describe the cut-and-try approach for process layout.
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-Involves searching for departmental
changes to reduce overall flow cost -Difficult to determine correct moves - Non-optimal and based on limited criteria (cost, flow and distance) |
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describe the Process Layout: CRAFT Approach
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It is a heuristic program; it uses a simple
rule of thumb in making evaluations: - "Compare two departments at a time and exchange them if it reduces the total cost of the layout." It does not guarantee an optimal solution. CRAFT assumes the existence of variable path material handling equipment such as forklift trucks. |
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What are the advantages of process layouts?
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Can handle a variety of processing
requirements Not particularly vulnerable to equipment failures Equipment used is less costly Possible to use individual incentive plans |
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what are the Disadvantages of Process Layouts
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In-process inventory costs can be high
Challenging routing and scheduling Equipment utilization rates are low Material handling slow and inefficient Complexities often reduce span of supervision Special attention for each product or customer Accounting and purchasing are more involved |
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describe the Fixed-Position Layout (Project)
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Layout in which the product or project remains
stationary, and workers, materials, and equipment are moved as needed Used when the product is bulky, large, heavy or fragile Minimizes the amount of product movement Missile Assembly, Large aircraft assembly Ship Building Bridge construction |
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describe cellular layouts
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Cellular Manufacturing
-Layout in which machines are grouped into a cell that can process items that have similar processing requirements Group Technology -The grouping into part families of items with similar design or manufacturing characteristics |
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describe Product layout
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Layouts that use standardized processing
operations to achieve smooth, rapid, highvolume flow Used for Repetitive or Continuous Processing |
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What are the Advantages of Product Layout?
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High rate of output
Low unit cost Labor specialization Low material handling cost High utilization of labor and equipment Established routing and scheduling Routing accounting and purchasing |
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What are the disadvantages of Product Layout?
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Creates dull, repetitive jobs
Poorly skilled workers may not maintain equipment or quality of output Fairly inflexible to changes in volume Highly susceptible to shutdowns Needs preventive maintenance Individual incentive plans are impractical |
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Name some other service layouts.
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Warehouse and storage layouts
Retail layouts Office layouts |
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what is line balancing?
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Line Balancing is the process of assigning tasks to workstations in such a way that
the workstations have approximately equal time requirements. |
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What is cycle time?
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Cycle time is the maximum time
allowed at each workstation to complete its set of tasks on a unit. |
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What is the equation for output capacity?
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output capacity = OT/CT
OT = operating time per day D = output rate demanded CT = cycle time = OT/D |
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What is the equation for the minimum number of workstations required?
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Nt = [desired output rate (D) * sum of task times (summation, E * t) ] / operating time per day (OT)
Nt = (D*Et) / OT |
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What is the equation for efficiency?
And what if efficiency is low? |
efficiency =
(sum of task times ) / (actual number of workstations * cycle time ) If Efficiency is unsatisfactory, rebalance using a different decision rule. |
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Name two intuitive rules for line-balancing
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Assign tasks in order of most following
tasks: Count the number of tasks that follow Assign tasks in order of greatest positional weight: Positional weight is the sum of each task’s time and the times of all following tasks. |
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Name the 6 line-balancing issues.
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Split the task
Can the task be split so that complete units are processed in two workstations? Share the task Can the task be shared so an adjacent workstation does part of the work? Use parallel workstations It may be necessary to assign the task to workstations that would operate in parallel Work overtime Example: the assembly line contains the following task times in seconds:40, 30, 15, 25, 20, 18, 15. The line runs 7.5 hours per day and demand for output is 750 per day. CT = (7.5x60x60/750)=36 seconds/unit At a rate of one unit every 40 seconds, we produce 675 per day, 75 short of the 750 needed. 68 Overtime = 75x40=3000seconds=50minutes Use more skilled workers Sometimes a faster worker may finish the required task on time. Here, the task time exceeds the cycle time by just 11%. Redesign It may be possible to redesign the product to reduce the task time slightly |
