2007: Assessing the challenges and rewards of design reuse

Manufacturing models may have hundreds of interrelated features, yet a growing number of companies are pushing to increase their reuse of design models. From the archives of Engineering Automation Report.

By Chad Jackson

Engineering Automation Report, May 2007—Design reuse: the idea is simple. Take past designs and repurpose them into new ones. The benefit? Starting with an already completed design allows engineers to avoid starting from scratch. Unfortunately, it?s not that easy. Design models with hundreds of interrelated features can be very difficult to change. They often end up spending more time fixing models than if they had simply started from scratch. Yet, despite these problems, some engineering organizations are seeing considerable success.

While all engineering organizations report that they are currently reusing designs, top performing ones are further along in the deployment of techniques and technologies to capitalize on design reuse. From product analysis, to NC programming and product design, these best-in-class companies are currently using these technologies to facilitate their design reuse strategies, or are planning to in the future.

The majority of engineering organizations have formal initiatives to increase reuse of designs, analyses and NC toolpaths, Aberdeen research shows that they face both serious known and unknown challenges. While some are taking steps in response, their strategies and tactics are only as good as the results they deliver. Aberdeen categorized survey respondents by measuring five key performance indicators (KPIs) that provide financial, process, and quality measures. This classification subsequently enabled differentiation between the “best practices” of the top performers and the practices of lower performing companies. Based on aggregate scores incorporating all five metrics, those companies in the top 20% achieved “best in class” status; those in the middle 50% were “average;” and those in the bottom 30% were “laggard.” As expected, companies in the different performance categories show substantial differences—with best in class hitting all five marks at a 76% or better average.

With the numbers quantifying a gap in performance, a lack of design reuse can be identified as a root cause of this difference. Companies that reuse designs shorten their design cycles, impacting how often an organization can hit their design release date. As such, it should be no surprise that this is exactly where the largest gap exists between the best in class and laggard performers.

Design reuse top challenges and responses from top performers

While a majority of manufacturers are pursuing a number of reuse initiatives, why is there such a disparity of performance between them? Aberdeen research points to the fact that many organizations struggle to change existing designs into new ones. Why the problem modifying designs? It point back to how the current generation of design tools fundamentally works.

Feature-based CAD tools allow users to create a sequence of individual geometric features that collectively form a complete design. Very often, interdependencies are created within the sequence of features. This interdependency can be incredibly powerful in making broad sweeping changes, yet it can also be constraining. A change to a feature early in the sequence can force a later feature change, creating invalid geometry.

The challenges manufacturing organizations face as a result are that model modification requires expert CAD knowledge, models are inflexible and fail after changes, and only original designers can change models successfully. These findings are a testament to the fact that feature-based models can be a barrier to design reuse. But these are challenges that can be solved. In fact, the best in class take very specific actions to increase design reuse despite these problems.

In fact, 71% of best-in-class companies train users to develop advanced CAD skills for model modification, with 36% also planning on detailing design information in models to enable designers other than the original to successfully change models and limit the reliance on 2D CAD data. While trying to meet these challenges head-on, some companies have been leaning on the expertise of third parties to help with training, freeing up resources to be able to focus on design. Top performing companies are also creating designs that are flexible, able to incorporate a wide range of modifications, with 64% using this as a means to further facilitate design reuse.

Do special efforts to increase design reuse pay off?

When it comes to design reuse, manufacturers are faced with a fundamental choice. They can dedicate resources and force end users to prepare designs for reuse. In the end, they face two fundamental questions:

  1. Will the special effort make a difference;
  2. Will the special effort distract my designers and engineers from completing the design by my design release date?

Overall, Aberdeen research finds that a special effort does make a difference. However, only pursuing the special effort in an integrated fashion allows manufacturers to avoid potential distractions.

Before a design can be reused, it must conform to a number of characteristics that are standard for the manufacturer. Geometry quality is of critical importance if NC toolpaths will be generated from the model. Parameter consistency and compliance to standards is important to the success of end-user searches for the part. Model flexibility is critical to modification of an existing design into a new design. It?s also important to include manufacturing information, as more and more companies turn to drawingless models according to the ASME Y14.4 standard.

Checking all of these characteristics manually is labor intensive and time consuming. To address this potential time sink, checker technologies automate the verification of these characteristics. Because of the benefits in time savings these techniques offer, it is no surprise that the top performers are more likely to leverage them. Top performers are twice as likely to perform checks for parameter consistency and model flexibility. Furthermore, a third of the top performers check for manufacturing information inclusion compared to none of the laggards.

How do these technologies help? There are a number of bottom-line differences associated with each. Because 48% of all companies are taxed with inflexible models that fail after changes, the top performers are using these technologies to make sure that their design models are in fact flexible and do not fail after changes. The top performer use of parameter consistency checks allows them to make sure their designs match company naming standards, thus becoming easier to find. Lastly, the best in class are pursuing the inclusion of PMI (product manufacturing information) in models for a reduced reliance on drawings for manufacturing. In this scenario, models are actually easier to reuse because engineers don?t have to manage the relationship between the drawing and the model; all the information needed to manufacture the design is right in the model itself. Companies that use this drawingless scenario are also less prone to mistakes that can be made from the interpretation of traditional 2D design data.

The research data used for this article, plus more detailed information, is available directly from the Aberdeen Group at http://www.aberdeen.com/link/sponsor.asp?cid=3908

At the time of this article Chad Jackson was research director and analyst for the Aberdeen Group.He is now president of Lifecycle Insights, and publisher of Engineering Matters.