Intended learning outcomes: Explain the work-center load and the load profile of a work center. Disclose capacity utilization and work center efficiency. Differentiate between rated capacity and theoretical capacity.
Continuation from previous subsection (1.2.4).
The following definitions are again related to the work center.
Work center load is the sum of the load of all operations for orders processed by the work center.
The load profile, or load projection, of a work center is a display of work center load and capacity over a given span of time. See Figure 1.2.4.1.
(Capacity) utilization is a measure of how intensively a resource is being used to produce a good or service. Traditionally, it is the ratio of its actual load to its theoretical capacity.
Figure 1.2.4.1 shows a typical picture of a load profile, under the assumption of continuous or rectangular distribution within a time period. Similar to product structure and the process plan, the load profile represents a scheme, or natural conception, from the perspective of the people responsible for the processing of the production order.
Fig. 1.2.4.1 The load profile of a work center (continuous and rectangular distribution).
It is also a common practice to set the capacity profile at 100%, that is, to make it the horizontal value and to express load as percentages thereof.
The production lead time ignores the actual capacity utilization of the work center, although utilization can strongly influence queue times. Mostly, for long-term planning, the lead time calculation according to Section 1.2.3, which is based on the average duration of operations and interoperation times, is sufficiently accurate. The shorter the planning term, the more important it is to consider capacity utilization when calculating lead time.
The animation shows a typical picture of a load profile, under the assumption of continuous or rectangular distribution within a time periode.
Press the start button to beginn the animation.
For a detailed analysis of the load profile, it is necessary to take a closer look at capacity.
Work center efficiency, or the efficiency rate of a work center, is a percentage, namely, “standard load divided by actual load” or — equivalently — “actual units produced divided by standard units to produce” (cf. [ASCM22]). This is calculated as the average of all operations performed by a work center.
Rated capacity, or calculated capacity, is the expected output capability of a work center, that is, theoretical capacity times capacity utilization times work center efficiency.
An example of theoretical capacity and rated capacity, along with detailed explanations of the terms, is shown in Figure 14.1.1.1. The above definitions, however, provide a basis for understanding important aspects for planning & control:
Standard load to be scheduled should always refer to rated capacity. To compare capacity with standard load, the capacity profile should always show theoretical capacity multiplied by efficiency.
Course section 1.2: Subsections and their intended learning outcomes
1.2 Business Objects
Intended learning outcomes: Present business-partner, and order-related business objects in detail. Explain product-related, process-related, and resource-related business objects. Produce an overview on rough-cut business objects.
1.2.1 Customer, Supplier: Business-Partner Objects; Order, Customer Order, Procurement Order, Production Order, Overhead Order: Order-Related Business Objects
Intended learning outcomes: Present in detail the order as a business object. Produce an overview on terms such as customer, supplier, business partner, due date, customer order, procurement order, production order, overhead order.
1.2.1b Order Promising, Order Confirmation, Order Status, Order Header, Order Main Section, Order Footer: Order-Related Business Objects
Intended learning outcomes: Produce an overview on terms such as order promising, order confirmation, order status. Differentiate between order positions for items (to be) delivered and labor (to be) performed.
1.2.2 Item, Component, End Product, Assembly, Raw Material, Spare Part, Item Family: Product-Related Objects
Intended learning outcomes: Produce an overview on business objects such as item, specializations thereof (particularly part and component), spare part and item family.
1.2.2b Product Structure, Bill of Material, Product Family, Product Variant, Commonality: Product-Related Objects
Intended learning outcomes: Explain the product structure and the bill of material. Differentiate between a convergent and a divergent product structure. Describe the concepts of product family, product variant, and commonality.
1.2.3 Operation, Operation Time, Setup, Run Time, Routing Sheet, Critical Path, Interoperation Time, Production Lead Time: Process-Related Business Objects
Intended learning outcomes: Present in detail business objects such as operation, setup and run time. Explain the routing sheet, the critical path, interoperation time and the production lead time.
1.2.3b Production Structure, Product Module, Cumulative Lead Time, Process Plan, Lead-Time Offset: Process-Related Business Objects
Intended learning outcomes: Describe the production structure, the product module, and the cumulative lead time. Disclose the process plan. and the lead-time offset.
1.2.4 Employees, Facilities, Workstation, Production Equipment, Work Center, Capacity, Load, Standard Load, Actual Load: Resource-Related Business Objects
Intended learning outcomes: Produce an overview on terms such as employees, facilities, workstations, production equipment, work center, capacity, load, work-center load. Differentiate between standard load and actual load
1.2.4b Work Center Load, Load Profile, Capacity Utilization, Work Center Efficiency, Rated Capacity: Resource-Related Business Objects
Explain the work-center load and the load profile of a work center. Disclose capacity utilization and work center efficiency. Differentiate between rated capacity and theoretical capacity.
1.2.5 Rough-Cut Product Structure, Rough-Cut Work Center, Rough-Cut Operation, Rough-Cut Process Plan: Rough-Cut Business Objects
Intended learning outcomes: Identify reasons and principles for defining rough-cut business objects. Disclose the rough-cut product structure, the rough-cut work center, the rough-cut operation, and the rough-cut process plan. Explain a way to derive a rough-cut process plan from a detailed process plan.
1.2.5b Bill of Resources, Product Load Profile: Rough-Cut Business Objects
Intended learning outcomes: Describe the bill of resources. Explain a way to establish a product load profile from a rough-cut process plan.
