Sales per unit area is a standard and usually the primary measurement of store success (Wikipedia). Firms sometimes pay a slotting fee to have their product placed on the retailer's shelves (Wikipedia).
Warehouse layout must accomodate material handling equipment.
A fixed position layout is used when the product is so large or located off site. In this case, the materials, tools and workers come to where they are needed on the product.
A process oriented layout is used when the number and types of products being produced are highly variable. Because of this variability, the like machines and functions are grouped together and the product travels to each function in the order of its need. When creating a process oriented (or functional) layout, the designer wants to minimize the total distrance travelled between functions. This total cost is a function of the distance (or cost) between functions and the number of trips made between each function in the business.
In manufacturing engineering, process layout is a design for the floor plan of a plant which aims to improve efficiency by arranging equipment according to its function. The production line should ideally be designed to eliminate waste in material flows, inventory handling and management. In process layout, the work stations and machinery are not arranged according to a particular production sequence. Instead, there is an assembly of similar operations or similar machinery in each department (for example, a drill department, a paint department, etc.)
In Cellular Manufacturing systems machines are grouped together according to the families of parts produced. The major advantage is that material flow is significantly improved, which reduces the distance travelled by materials, inventory and cumulative lead times (Wikipedia). Processes are arranged in a U-shape so that the beginning and end of the material flow within the cell are near each other. This allows quick rebalancing of tasks without redesigning stations, because workers can cross the aisle (Wikipedia).
The TAKT time (cycle time) for a work cell is the pace of production that is required to meet customer demand (Wikipedia).
TAKT time = total work time available / units required
To calculate the number of operators needed in a work cell:
# workers = total operation time for all steps / TAKT time
In a product layout, the workstations and equipment are located along the line of flow of the work units (Wikipedia). This is commonly understood as an assembly line, which is a manufacturing process (most of the time called a progressive assembly) in which parts (usually interchangeable parts) are added to a product in a sequential manner using optimally planned logistics to create a finished product much faster than with handcrafting-type methods (Wikipedia).
Production leveling (smoothing) reduces waste by producing intermediate goods at a constant rate (Wikipedia). To balance (level) a production line, follow these steps:
(1) Identify all the process steps required, including the time for each task (Ti), the immediate predecessor for each task, and the total time for all tasks (SumTi).
(2) Draw a precedence diagram based on the information gathered in step 1. This diagram is used when assigning individual tasks to workstations.
(3) Determine the takt time for the line. Takt time is the maximum allowable time between completions of successive units on the line. Takt time is computed as the available production time (e.g. minutes in the shift or day) divided by the required output rate:
Takt time = available production time / required output rate
(cycle time is the actual time between completion of units)
(4) Compute the theoretical minimum number of workstations needed. The shorter the takt time, the more workstations that are required. This is because the tasks will need to be divided across more workstations to ensure that cycle time, which is determined by the total amount of work in the largest workstation, remains below the takt time.
Wmin = total time for all tasks (e.g. åTi) / takt time
(5) Working on one workstation at a time, use a decision rule to assign tasks to the workstation. Start with the first workstation, and add tasks until you reach the point that no more tasks can be assigned without exceeding the takt time. If you reach this point and all the tasks have not been assigned yet, close the workstation to any more tasks and open up a new workstation. Repeat the process until all tasks have been assigned.
Be sure not to assign a task to a workstation unless all direct predecessors (if any) have been assigned. Common decision rules for determining which task to assign next are to:
1) assign the largest eligible task that will still fit within the workstation without exceeding the takt time,
2) assign the eligible task with the most tasks directly dependent on it, or
3) assign some combination of the two.
(6) Evaluate the performance of the proposed line by calculating some basic performance measures:
Cycle time (CT) = maximum amount of time spent in any one workstation
Idle time (IT) = [actual number of workstations (e.g. Wactual) * CT] – total time for all tasks (e.g. SumTi)
Percent idle time (PI) = 100% * [IT / total time for all tasks (e.g. SumTi)]
Efficiency delay (ED) = 100% - PI
In general, solutions with low idle times and high efficiency delay values are considered superior.
The objective is to arrange the different functional areas (departments) in such a way that departments that should be close to one another (such as packaging and shipping) are, while departments that don’t need to be near one another aren’t).
You can use qualitative (“undesirable”, “desirable”, “critical”) or quantitative methods.
A quantitative method commonly used is to locate departments in such a way as to minimize the total distance traveled, given a certain number of interdepartmental trips per time period.
Steps for departmental location: