Jan #1 - Factory Layouts Flashcards
Plant layout is dictated by two primary factors: product type and manufacturing quantity. What are the four types of classical layouts?
- Fixed position layout 2. Product layout 3. Process layout 4. Group layout
There are 9 major characteristics defining a good layout. List as many as you can. Hint: we want to minimise four things, and maximise five things.
Minimised: materials-handling costs, bottlenecks, cycle time, and waste Maximised: efficient space usage, ease of accessibility by support services, ease of communication, flexibility, and health and safety compliance
Categorise the four types of plant layout according to product variety and production quantity
Fixed position layout: lowest quantity, greatest variety Process layout: slightly greater quantity, slightly lower variety Group layout: much greater quantity, much less variation Product layout: greatest quantity, least variety
‘Process layout’ is one of the four types of classical layouts. Describe this layout, and list 4 advantages and 4 disadvantages.
Description: machines arranged according to function (e.g. lathes placed together in “lathing department”) Advantages: equipment/worker flexibility, high job satisfaction, high product variability is possible, low-cost general purpose equipment. Disadvantages: costly material handling, low equipment use, complex control/supervision, high-cost skilled labour needed
“Line Balancing” is a heuristic used in layout planning whereby we attempt to balance an assembly line such that the amount of work at each workstation is equalised. Define the following terms related to line balancing: cycle time, flow time, efficiency, and the minimum number of stations.
The cycle time is the maximum time spent at any station, while the flow time is the time taken to complete all stations.
Facility planning never ends until the plant is torn down. What are the five steps involved in facility planning?
- Define/redefine the objectives of the facility 2. Determine interrelationships between activities 3. Determine space requirements for all activities 4. Generate alternative facility plans 5. Evaluate alternatives, select most optimal, implement, review
Consider the process shown below. If it is a 40 hour working week, and we want to produce 6000 units per week, how can we use the “Line Balancing” heurestic to determine a layout? Calcultate the cycle time, minimum number of workstations, and efficiency.
Cycle time = (40*60 minutes)/(6000 units) = 0.4 min/unit
N = (0.1+0.2+0.3+0.4)/4=2.5=3 workstations
E = (0.1+0.2+0.3+0.4)/(3*0.4)=0.833=83.3%
Lets say we are using Muther’s systematic layout planning procedure, and we have already determined the FLOW OF MATERIALS (1) and the ACTIVITY RELATIONSHIPS (2). Once we have created an activity relationship matrix (shown below), what do we do next?
We then create a RELATIONSHIP DIAGRAM (3), and then use the SPACE REQUIREMENTS (4) and SPACE AVAILABLE (5) to create a SPACE RELATIONSHIP DIAGRAM (6). These diagrams are shown below.
Complete the following table
‘Fixed position layout’ is one of the four types of classical layouts. Describe this layout, and list 2 advantages and 3 disadvantages.
Description: very large items (e.g. ship) stay in fixed location, and equipment/workers are brought to it Advantages: less movement of work item, more continuity of workforce Disadvantages: need skilled/versatile workers, equipment movement is costly, and there is low equipment use
‘Product layout’ is one of the four types of classical layouts. Describe this layout, and list 4 advantages and 4 disadvantages.
Description: product is produced through continuous process (e.g. automobile appliance lines) Advantages: high equipment utilisation, reduced material handling, less in-process inventory, simplified production planning. Disadvantages: lack of flexibility, worker monotony, high-cost specialised equipment, interdependent operations
One example of a heuristic used in layout planning is Muther’s systematic layout planning procedure. What does the flow diagram for this heuristic look like?
We often use heuristics in the planning of plant layouts. What are heuristics, and why do we use them?
Experience-based methods that reduce the need for calculations, but are fallible and do not guarantee a correct solution. They offer time saving approximations in preliminary design.
How do systems engineering and systems thinking relate to manufacturing systems?
Systems engineering/thinking allows us to approach a complex system by considering the interrelationships and patterns between the many elements in the system. Manufacturing systems fall into this category, so systems engineering/thinking allows us to plan and control their behaviour to maximise efficiency.
‘Group layout’ is one of the four types of classical layouts. Describe this layout, and list 4 advantages and 1 disadvantage
Description: machines grouped according to process requirements for similar items requiring similar processing. Advantages: economy of scale achievable, just-in-time manufacturing feasible, low setup times, low in-process inventories Disadvantage: lack of flexibility (only one disadvantage so I guess this is a good layout?)
“Block Diagramming” is a simple heuristic we can use to generate a plant layout. Using the table below, describe how this heuristic could be applied to generate a plant layout.
We first calculate the composite (two-way) movements, and then devlop trial layouts such that the number of non-adjacent loads is minimised. This is shown below.
