The concurrent engineering design process was developed to ameliorate the problems associated with the over the wall design process. You can learn about the over-the-wall design process by clicking here. In short the over-the-wall design process consisted of different departments in a company working on designs in isloation and then Throwing the project over the wall to the next department. The complaints about the over-the-wall design systems are discussed below.
The products took too long to get to the market.
Because many products has to be sent back to previous departments for rework, the length of time for a product to get through the system to market was long. Often competitive products would be the first on the market and take the majority of the profits.
The products produced by the over-the-wall method cost too much.
The root cause of this problem could be traced back to the fact that manufacturing engineers were not consulted about the design until the design engineers had finished the design. Often the manufacturing engineers requests for design changes to make the design easier and cheaper caused delays while the design engineers considered the impact of the requested design changes. Figure one shows that early design decisions have much greater impact on the final cost of a product than do decisions made later in the design process. For instance a car manufacturer’s decision about what type of drive train to use is made early in the design process and has a huge impact on the cost of a car. Should the car be powered by a gas engine, diesel engine, electric motor, a hybrid system or a fuel cell? Whereas, the plastic slected to manufacture an interior trim piece has a much more limited impact on the cost of a car and is made much later in the design process. You can read a funny story about design for manufacture by clicking here.
Figure 1. The cost impact of making a design decision as a function of the stage in the deisgn process.
The products did not meet the needs of the customers.
After marketing had identified the need and passed it to the research engineers to investigate the possible technologies, the marketing people were not consulted. Often the needs of the customer were lost in the process and the back and forth between the departments. Therefore the final product did not meet the needs of the customer.
The Tenets of Concurrent Engineering
All Stakeholders represented on the design team. From the beginning of the product development effort until the product goes to the customer all stakeholders are represented on the design team. Example of stakeholders include;
- Suppliers of key components
Problems are identified and solved as early as possible in the design process. Problems are easier and less expensive to solve early in the design process. For example, a tolerance problem that is caught before any parts are made is much easier and less expensive to fix than a tolerance problem that is found when parts do not assemble correctly. In the first case a changing the tolerances on the drawings of the parts involved may solve the problem. In the second case, the solution requires not only a change to the drawings but also changes to tooling that makes the parts involved and finally the parts on hand must be reworked or scrapped. The costs add up fast! Click here to learn about a tragic tale of missed opportunity.
Advantages of Concurrent Engineering
Shorter Time to Market. Figure 2. shows how the concurrent engineering strategy shortens development time. Between 24 months and 18 months before the launch of the product, shown as month zero on the horizontal axis, design teams using concurrent engineering techniques made many more design changes than design teams using over-the-wall techniques. However, the concurrent engineering teams made far fewer design changes in the 12 months before the launch of the product while the over-the-wall teams filed a huge number of changes in the 6 months before and after the launch date.
Figure 2. The number of design changes made versus time.
Less Costly Product Development Projects. Figure 3. shows the product development costs versus time for both the concurrent engineering strategy and the over-the-wall strategy. Note the similarities to the trends seen in figure 2. In the beginning the the concurrent engineering strategy costs more because of the cost paying representatives of all of the stakeholders to participate on the design team. The over-the-wall strategy is expensive near launch because many people are added to the design team correct design issues that were not detected and dealt with earlier in the process. Click here to read about Caterpillar’s problems with over-the-wall design processes.
Figure 3. The product development cost versus time.
Concurrent engineering has become the standard method for product design in most progressive companies. However, when management wanted to assert more control over the projects and discontinue projects that were not going well, the Stage Gate process was born. Learn more about the Stage Gate process by clicking here.