Productions and Operations Management

What are some reasons project scheduling not done well?
Uncertainties inherent in the activities comprising the network of any project make it necessary to update the schedule on a regular basis
project control always focus on the critical path
In many situations, it is not the activities on the critical path which can cause problems, but rather noncritical activities, which for various reasons, become critical.
Generic product development process
the basic steps needed to design a product. This process represents the basic sequence of steps or activities that a firm employs to conceive, design, and bring a product to market.
Phase 0, Planning
The planning activity is often referred to as “phase zero” since it precedes the project approval and launch of the actual product development process. This phase begins with corporate strategy and includes assessment of technology developments and market objectives. The output of the planning phase is the project mission statement, which specifies the target market for the product, business goals, key assumptions, and constraints.
Phase 1, Concept development
In the concept development phase, the needs of the target market are identified, alternative product concepts are generated and evaluated, and one or more concepts are selected for further development and testing. A concept is a description of the form, function, and features of a product and is usually accompanied by a set of specifications, an analysis of competitive products, and an economic justification of the project.
Phase 2, System-level design
The system-level design phase includes the definition of the product architecture and the decomposition of the product into subsystems and components. The final assembly scheme for the production system is usually defined during this phase as well. The output of this phase usually includes a geometric layout of the product, a functional specification of each of the product’s subsystems, and a preliminary process flow diagram for the final assembly process
Phase 3, Detail design
The detail design phase includes the complete specification of the geometry, materials, and tolerances of all of the unique parts in the product and the identification of all of the standard parts to be purchased from suppliers. A process plan is established and tooling is designed for each part to be fabricated within the production system. The output of this phase is the control documentation for the product – the drawings or computer files describing the geometry of each part and its production tooling, the specifications of the purchased parts, and the process plans for the fabrication and assembly of the product. Two critical issues addressed in the detail design phase are production cost and robust performance.
Phase 4, Testing and refinement
The testing and refinement phase involves the construction and evaluation of multiple preproduction versions of the product. Early (alpha) prototypes are usually built with production-intent parts – parts with the same geometry and material properties as intended for the production version of the product but not necessarily fabricated with the actual processes to be used in production. Alpha prototypes are tested to determine whether the product will work as designed and whether the product satisfies the key customer needs. Later (beta) prototypes are usually built with parts supplied by the intended production processes but may not be assembled using the intended final assembly process. Beta prototypes are extensively evaluated internally and are also typically tested by customers in their own use environment. The goal for the beta prototypes is usually to answer questions about performance and reliability in order to identify necessary engineering changes for the final product.
Phase 5, Production ramp-up
In the production ramp-up phase, the product is made using the intended production system. The purpose of the ramp-up is to train the work force and to work out any remaining problems in the production processes. Products produced during production ramp-up are sometimes supplied to preferred customers and are carefully evaluated to identify any remaining flaws. The transition from production ramp-up to ongoing production is usually gradual. At some point in this transition, the product is launched and becomes available for widespread distribution.
technology-push
would be more narrowly focused in phase 0 and phase 1 of Marketing. There focus would be narrower because you would only look at market segments that could benefit from the application of your technology.
Industrial design is concerned
designing a product from the end-user’s point of view, such as aesthetics and user friendliness of the product.
Design for manufacturability
makes the product design less complicated and easier to manufacture. Very often it results in less parts, smaller size, increased reliability, and lower cost.
Quality Function Development (QFD)
a process that helps a company determine the product characteristics important to the consumer and to evaluate its own product in relation to others.
(QFD) pro
helps to get the voice of the customer into the design process using interfunctional teams.
(QFD) con
The limitations of QFD relate to the culture of the organization. In the United States, we tend to be vertically oriented and try to promote breakthrough. This can work against interfunctional continuous improvement mentality through interfunctional teams; this would lead to tremendous improvements in productivity.
The limitations of QFD relate to the culture of the organization. In the United States, we tend to be vertically oriented and try to promote breakthrough. This can work against interfunctional continuous improvement mentality through interfunctional teams; this would lead to tremendous improvements in productivity.
The primary concerns come from uncertain demand for the drug and the high capital investment typically needed for modern drug production. Being a new drug, there are no historical sales data on which to base forecasts of future demand. If forecasts are too high, significant capital resources will be underutilized. If forecasts are too low, there may be insufficient capital resources to meet the actual demand, resulting in lost sales when the price for the new drug is typically highest.
2.) List some practical limits to economies of scale; that is, when should a plant stop growing?
A plant should stop growing when its long-run average cost curve hits the inflection point. However, since this determination is often difficult to make (in the short run), other factors such as coordination problems, excess capacity, capacity imbalance, and market shifts indicate a need to consider setting capacity limits.
when costs per unit goes up!!
a) some capacity balance problems faced by an airline terminal
Congested flight arrival/departure scheduling typically leads to problems throughout the system, including waiting areas, distances from boarding gates, ground crew requirements, runways, baggage handling, etc.
b) some capacity balance problems faced by a university computing center.
The number of computer workstations, the size of each workstation (room for student papers, etc.), the mix of different computer types (Mac or PC), the number of printers, the capacity of the network access, study space for students waiting. These problems are exacerbated by surges in demand during certain points in the semester (e.g. finals week).
c) some capacity balance problems faced a clothing manufacturer
Many manufacturers now use highly decentralized shops to make clothes. This means that capacity of multiple sites must be accounted for in planning production.
What are some major capacity considerations in a hospital
Some capacity considerations are size and composition of nursing staff (RNs vs. LPNs), balance between operating room and intensive care units, emergency rooms, how many beds are available.
How do they differ from those of a factory?
One of the differences in capacity considerations between a hospital and a factory is that a hospital can add capacity rather quickly in the short run through “simply” adding more staff and beds. A factory is usually technologically limited, must plan well in advance to add major amounts of capacity. The general uncertainty which surrounds the demand for hospital services on any given day is much greater than would be faced at a factory. The factory management generally has the ability to backlog demand in such a way as to achieve more efficient levels of capacity utilization than does a hospital.
Management may choose to build up capacity in anticipation of demand or in response to developing demand. pro
The strategy of building up capacity ahead of demand is a risk taking stance. Investment is based on projections. This investment involves costs for new facilities, equipment, human resources, and overhead. If the demand materializes, the investment is worthwhile since the firm may capture a large amount of market share. If it does not materialize, the firm must redirect the invested resources. This strategy is most appropriate in high growth areas.
Management may choose to build up capacity in anticipation of demand or in response to developing demand. con
If the demand materializes, but the capacity planning strategy is risk adverse, i.e., building capacity only as demand develops, then most likely market share will be lost. The growth in demand will encourage new entrants resulting in more competition. The risk adverse strategy may be most appropriate for small firms who cannot afford to invest in un-proven prospects. To prevent potential loss of market share, firms may choose to incrementally increase capacity to match the increase in demand.
Food can rot, technology becomes outdated quickly
What is capacity balance
In a perfectly balanced plant, the output of each stage provides the exact input requirement for the subsequent stage. This continues throughout the entire operation.
Why is capacity balance hard to achieve
This condition is difficult to achieve because the best operating levels for each stage generally differ. Variability in product demand and the processes may lead to imbalance in the short run.
What methods are used to deal with capacity imbalances
There are various ways of dealing with capacity imbalances. One is to add capacity to those stages that are the bottlenecks. This can be achieved by temporary measures such as overtime, leasing equipment, or subcontracting. Another approach is to use buffer inventories so that interdependence between two departments can be loosened. A third approach involves duplicating the facilities of one department upon which another is dependent.
a+4m+b/6
mean (expected time) t=
(b-a/6)^2
variance (sigma squared)=
D-Te/√Σσ²
z score from the critical path