Concurrent engineering is defined as “a systematic approach to the integrated, simultaneous design of products and their related processes, including manufacture and support. This approach is intended to cause the developers, from the outset, to consider all elements of the product life cycle from conception through disposal, including quality, cost, schedule, and user requirements”
Why talking about concurrent engineering?
CALS is a project for Computer aided acquisition and logistic support. CALS started in the USA in 1985, launched by the DOD, Ministry of Defense, with a budget of 2 billion of $ per year.
CALS wants to exchange and manage the technical information needed for the design, production, purchasing and logistic for a weapon system.
In France, CALS France started only on 1990. It was launched by the DGA (Direction Générale de l’Armement), in charge of the projects Rafale and Apache.
It concerns about 20 to 30% of the turnover for the great enterprises, with some hundred of equipment providers, about 10.000 SME or 250.000 peoples.
Germany started a CALS project in 1992
Why to start such CALS projects ?
-On B1 bomber: the documentation, about 1,4 million pages, was more heavy than the bomber itself
-In US Navy: 200.000 manuals, 50 million pages, what can cause a drop in the level of floating of the Kennedy carry-plane of one meter
-5 to 8% of the fatal accidents which have occurred during military operations are due to errors slipped into the documentation of the materials
-US Air Force spends 3,5 million dollars per year because of the errors of documentation
So the question was: how to avoid such troubles ?
For that; they put a strategy in 3 steps:
-Before CALS, the technical information are exchange by paper, among the private companies and the military establishments. We did technical drawings, we did reports, we did documentation, we did copies of these documents and we sent this documents to a lot of people. Of course, all the modifications in the documents were not transmitted to all the actors receiving the previous version. So we can have different versions of the same document in different places.
-Starting in 1985, we expect to be able to exchange the different documents on electronic format, and for that, we have to create some standards. It is the time to standardize the links between computer (serial link RS323), the format of the transfer file (ASCII for text, postscript for writers), …
-The third step has as goal to be able to store the different electronic documents in a common database and to ask each of the concerned actor to get the document at the time they need it, in order to always have the last version of this document.So it was the beginning of concurrent engineering, integrated design, and was done with the introduction of standards.
We are speaking about design of product or system, and we also have to take into account a common definition.
For us, the design starts with the specification of the product, including the wanted functions, the loads and conditions to use this product, its lifetime without defects, the environment or context in which the product has to be used, …
The design only finishes when we get for the product the forms, dimensions, materials, fabrication processes, …, and now the recycling processes.
FACOM, a French machine maker for automotive industry, considered that the design is finished only six month after being put on the market. Because the first real test can always bring some requests from the customers.
What about concurrent engineering?
Two aspects of Concurrent Engineering that distinguish it from conventional approaches to product development are cross-functional integration and concurrency.
Conventional NPD programs execute concept exploration, product design, testing, and production activities serially. Each of these development activities is typically controlled by only one functional organization at a time (e.g., marketing, engineering, manufacturing). When one organization completes its design and development activities, it hands over control and responsibility to the next organizational function.
In the Concurrent Engineering approach, integrated, multi-functional teams work together, simultaneously attacking multiple aspects of new product development. Control and responsibility are shared among functions and development activities
Linear versus concurrent engineering
Concurrent engineering includes designing for assembly, availability, cost, customer satisfaction, maintainability, manageability, manufacturability, operability, performance, quality, risk, safety, schedule, social acceptability, and all other attributes of the product highlights the contrast between concurrent engineering and conventional engineering design.The concurrent engineering environment has the following characteristics:
•Reduced cycle time
•Overlapping of functional activities
•Collaboration in functional decisions
•Concurrent evolution of system and Component decisions
In linear model, the different steps of the design process are put sequentially, with the product opportunity, the concept development, the product design, the process design and the commercial production.
In concurrent engineering , We are not obliged to finish one step to start the next one. And we can have partly overlap, largely overlap or no overlap. Here, the degree of concurrency is the activity overlapping. The question is: How do we make decisions for these overlapping activities ?
we have to define common interfaces between the different tasks and in Collaborative engineering, we create synergy between actors.
Source: ECQA certified profession.
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