Intended learning outcomes: Explain an example of a work-center-load profile. Present an example of a load profile known as an overload or underload curve along the time axis.
The load profile is a display of the work center load and capacity over a given span of time (Section 1.2.4).
For load profile calculation we assume, as an approximation, that operations will be executed as scheduled (see Section 13.3). Thus, in the simplest case, the method places the operation load in the time period that contains the start date of the operation.
Figure 14.2.1.1 shows a load profile over two time periods for six production orders, P1, . . . , P6, each with operations at two different work centers, work center A and work center B.
Fig. 14.2.1.1 Example of a work center load profile.
At the top of Figure 14.2.1.1, we can see the orders corresponding to the results of lead-time calculations. Each operation has a start date, which may be the earliest, latest, or probable date, depending on the scheduling technique used.[note 1404]
The bottom of the figure shows the loads for these operations along the vertical axis. The “preload” represents operations for orders that were loaded before orders P1, . . . , P6. The method then adds together the operation loads in each time period on the planning horizon to create a load profile.[note 1405]
Figure 14.2.1.2 provides an example of a load profile known as an overload or underload curve along the time axis.[note 1406]
Fig. 14.2.1.2 An example of a load profile.
The use of different colors or hatching patterns make individual orders stand out in the profile. This can also highlight partial sums for particular order categories, such as:
- Scheduled load, caused by released orders (released orders with provisional completion date can be highlighted by an additional category)
- Firm planned load, caused by planned orders with fixed completion dates
- Planned load, caused by planned orders with provisional completion dates
The information may change according to the length of the chosen periods, that is,
- By selecting shorter load periods, the overload and underload curve is more precise
- Longer time periods reveal a longer-term trend, with the short-term fluctuations evened out
Course section 14.2: Subsections and their intended learning outcomes
14.2 Infinite Loading
Intended learning outcomes: Present load profile calculation and problems associated with algorithms for load profile calculation. Explain methods of balancing capacity and load. Describe order-wise infinite loading.
14.2.1 Load Profile Calculation
Intended learning outcomes: Explain an example of a work-center-load profile. Present an example of a load profile known as an overload or underload curve along the time axis.
14.2.2 Problems Associated with Algorithms for Load Profile Calculation
Intended learning outcomes: Describe the problem of calculating capacity per load period. Explain the problem of load assignment for one operation during the load periods. Present the issue of calculating the load in a given time period when various operations occur only partly within the time period.
14.2.3 The Cumulative Load Profile
Intended learning outcomes: Describe the analysis of the load profile and the cumulative load profile.
14.2.3b Adapting Capacity to Load Rather Than Load Leveling
Intended learning outcomes: Explain possible strategies for capacity planning, in case of a trend toward persistent overload or underload, or in case of frequent and infrequent self-compensating fluctuations. Differentiate between adapting capacity to load and load leveling. Present an evaluation of the technique. Identify its limitations and typical areas of application.
14.2.4 Order-Wise Infinite Loading
Intended learning outcomes: Describe order-wise infinite loading. Identify the suitability of order-wise infinite loading.
