The limitations of traditional engineering approaches

*All design must keep the end product in mind.
*The aim is to produce an artifact, which can provide something approaching the best means of meeting a need at an appropriate manufacturing cost.
*The end must be hardware, and in order to achieve this the interface between design and manufacture must be crossed.

The life cycle of a product can be divided into three stages: the design phase, the manufacturing phase and the end-of-life phase.

The design and manufacturing phases were separated and occurred sequentially, with process planning as the activity that bridged the gap between the two phases

In many large-volume industries the traditional product development route has been to design and make prototype components, then test them and redesign as necessary and then re-test to iron out any faults. This process leads to satisfactory, but not optimal, designs at reasonably low cost, but it contributes to long design and development times.

Limitations of traditional approaches: Information on how to achieve product quality, cost and variety is not fed back to the designer at a sufficiently early stage; the whole process has taken too long.

Today more than ever, it is important for the product designer to understand the implications of decision making on the manufacturability of a product. For a commercial product to fair well in the marketplace, the design needs for the product must first to be met. However, no company will survive in today’s competitive market selling an equivalent product at a higher price. The key to any manufacturer’s success is to develop a good product that is easily manufactured. Whether a product is produced manually or using automatic equipment, the key to successful production is good design.
The design should not be overspecified so as to include tight dimensional tolerances. The surface finish, for instance, should be specified to be the largest value possible that meets the functional needs. Deep holes (one with a length/diameter ratio greater than 3.5) should be avoided in a part by changing the hole diameter or modifying the hole length. Similarly, parts that must be assembled should be designed so that tolerance “stacks” do not introduce any assembly interference and assembly takes place in a logical manner.

Current Themes in Manufacturing Engineering

Quality: A modern approach to quality replaces the notion of acceptable of defects with a zero-defect philosophy. The word quality is used here in the sense of meeting or exceeding the customer’s expectations.

Total quality: The achievement of high quality is the responsibility of everyone in an organization.

Two approaches are characteristic of a “total quality” approach to engineering. The first is to see things in system terms: products are systems from which a certain performance is required; the manufacturing processes and their disposition for a product constitute a manufacturing system; the manufacturing organization itself is a system with certain goals and characteristics. The second approach is to adopt a philosophy of continuous improvement.

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