WEB-TeK 2002 Applications

"Best Practices in CAD Data Conversion"
by
Butch Smigel & Derek Neiding
• Featured in Solid Solutions Magazine Nov./Dec. 2001

Introduction

Motivated to compete in today's market or spurred on by missed sales opportunities and perceptions of antiquation and inefficiency, many manufacturing organizations are re-engineering themselves and redefining their business and engineering objectives. As a result, these companies are striving to increase engineering data throughput, reduce design process mistakes, maximize downstream applications, secure collaborative engineering tools and attract and maximize technical talent. Furthermore, these companies are deploying advanced technologies such as product data management (PDM) and are converting their 2D design systems to 3D solid modeling systems to accomplish their goals.

Successful organizations in the process of implementing a major CAD conversion find it imperative to collaborate with leaders about their plans for data management and information sharing. However, enterprise-level planning should by no means be a deterrent to developing sound engineering standards, creating a plan for deploying PDM or proceeding with the process of CAD data conversion. In fact, a well-thought out and executed CAD conversion effort provides a strong foundation for future data management strategies. This means utilizing best practices; establishing and testing engineering standards; categorizing part, product, and assembly data; refining the engineering change and approval process and creating a momentum within the organization toward effective and efficient information sharing and management.

Manufacturing organizations in the midst of planning a conversion of their legacy CAD data to a new solid modeling package will have to make some difficult decisions about the scope and depth of the conversion process. Similarly, guaranteeing a significant return on one's investment is elusive in the short term and questionable at best down the road. But measurable gains can be made if best practices are incorporated and careful consideration is given to the fundamental method for planning and implementing the conversion.

In this three-part series, we will address several issues involved in implementing a potentially large-scale conversion, focusing heavily on sound, upfront procedures when planning or starting a conversion. We do not intend to take you through the details of the conversion process nor to preach the definitive approach to proceed, but rather to lay some important guidelines for an efficient and effective conversion that meets the engineering and business goals of your organization. We will focus on maximizing limited resources within an organization, pointing out common mistakes, achieving a significant return on the investment, and illustrating practical approaches to CAD data conversion.

This series is not intended for all manufacturing environments but rather addresses medium-to large-size organizations that are considering, or have begun, replacing their legacy CAD system with a solid modeling system. Legacy systems may stay in place for specific groups and/or projects, but a planned conversion is extensive and crosses over separate, even autonomous divisions or business units. For the purpose of this series, we also assume that the company intends to standardize the new software throughout the organization and, through that process of standardization, to address questionable engineering procedure and practices.

The implementation of a new modeling package is often a result of a manufacturing firm re-engineering itself by examining and redefining its business and engineering objectives. Typically, the resultant objectives include the following:

Increase Engineering Data Throughput - Through the proper implementation of a modeling package and the ready availability of modeled legacy CAD data, new assembly configurations and part iterations become smooth, quick, and efficient constructions.

Reduce Design Process Mistakes - Particularly in the early stages of design when overlooked errors take on much greater downstream damage, having a modeling tool that allows for clearer visualization and a simplified means to check for fits and interference is very helpful to both the designer and the company's bottom line.

Maximize Downstream Applications - Modeling packages increase the ability to use state-of-the-art analytical and manufacturing software in downstream applications, thus creating an integrated and fully compatible engineering environment. In addition, today's modelers make the analysis and machining processes easier by eliminating programming and incorporating a seamless union between the modeling software and the specialized application.

Secure Collaborative Engineering Tools - In pursuing a true, simultaneous group effort in developing product, modeling software offers the advantage of having the necessary intelligence to process information easily and allow for expedient and effective feedback among group members.

Attract and Maximize Technical Talent - If you want innovative products introduced to the market place in a timely manner, it is important to the state-of-the-art tools to first attract talent and then allow them to maximize their capabilities.

A common mistake firms make is to treat conversion as an afterthought, an issue that seems to pop up out of nowhere and has little connection to the company's new attitude. In planning and implementing a CAD conversion (an integral part of any significant move to solid modeling), you need to look for fundamental guidance from your original business and engineering objectives used in evaluating the purchase of the new CAD system. Any individual or CAD team should be well aware of these objectives and should be certain they are being addressed as conversion planning and implementation proceeds. If there is not a clear understanding of your objectives in bringing in a new modeling package, it is very likely the conversion, if it proceeds at all, will not accomplish what it should.

It is also very helpful in the planning stage if broad business objectives narrow down to increasingly specific technical objectives. Although properly laid-out objectives can sound inspiring at any level of the organization, it is very difficult for an engineering group or conversion team to grasp or justify how converting hundreds or thousands of legacy prints meets the business objective of "reducing overall company costs by 5 percent." Conversely, justifications are not as obtuse when the goal is to "reduce the time to market of a product line from 24 to 16 weeks."

Much of business directly or indirectly boils down to some form of return on investment (ROI), and data conversion is no exception. However, unlike other straightforward projects that have more historic and objective data to fall back on, CAD data conversions often have nebulous future returns and often require highly subjective and speculative assumptions. In attempting to get a handle on the value and subsequent scope of a CAD conversion, it is important to evaluate the following:

The Value of the Product/Product Line to the Company - In evaluating whether to model certain products or product lines, the most significant issue is the value of these parts to the company and if that value would be sustained or increased if they were modeled. Their value may be determined in many ways, such as the revenue or profit they generate, their brand recognition to the company, their dependence or influence on other products, or their future potential growth. The question to ask for each product is to what degree it forms an integral part of the organization and whether or not it is worth the effort.

The Value of the Product/Product Line as Modeled - A part or assembly should be appraised for its value as a 3D model as opposed to its legacy representation. The modeled part or assembly is likely to be easier to manufacture, visualize, analyze, modify and market, but a quantitative value also need to be associated with that improvement in order to categorize product and product lines into particular levels of modeling value.

The Cost to Model the Product/Product Line - After the modeling methods are agreed upon, the determination of the cost to convert CAD data is rather straightforward and predominately an accounting practice. However, some other less noticeable costs are associated with the conversion, such as the opportunity cost of technical staff not working on new products or improving existing ones; the training and developmental costs of bringing new personnel on staff to help with the conversion; and the startup costs resulting from changing direction and scope several times before the project reaches a production mode.

Conversion Evaluation Model - Once values and costs are estimated, a graphic representation can visually determine a gross hierarchy of conversion. As illustrated in Figure 1, the top right cube area represents the greatest conversion value: high product importance to the company, high value in having models and low cost to model. This graph assumes an evenly weighted value to each of the axes.

However, it is very likely within an organization that one or more of the value criteria will be weighted more heavily, thus skewing the graph and turning the cube into a different shape.

This model is better used as a means to eliminate or re-prioritize potential conversion candidates, rather than pick out best candidates for conversion. Again, Figure 1 shows such a volume of minimal value in the lower left corner. In a CAD conversion project, there is often more confidence in determining what lacks value than in what truly contains value. As a result, a method frequently employed is to start from the least desirable parts and assemblies and expand out to those that start to show significant value. Once the poor candidates are eliminated, whatever remains constitutes the scope of the conversion project.

Although the graph gives a clear picture of how the different values and costs interplay, assigning of measurable numbers is the ultimate goal and can be performed in a number of different ways.

The chart above illustrates one such way in which parts and assemblies are assigned numbers relative to their value and costs. The weighting factor, often a very contentious issue because of its subjectivity, adds greater value to an area an organization deems appropriate. The resultant sum of the three areas is a number that can be used to rank product or product lines and determine a hierarchy of conversion.
To sum up, any CAD conversion should be based on sound evaluation of need and objectives. In Part II, we will talk about how to determine the scope of your conversion to 3D CAD, and ways to ascertain the quality you want.

Butch Smigel, P.E. is president of DAD Engineering Group, a mechanical engineering firm. He previously spent 12 years as a design and project engineer, directing product development and data management implementations. A Professional Engineer with an MBA from Baldwin Wallace College in Berea, Ohio. He can be reached at bsmigel@dad-inc.com.

Derek Neiding is a senior product data management (PDM) consultant for the Razorleaf Corporation, a PDM implementation and consulting firm. He has worked as a project/implementation leader, is experienced in relational database/CAD/PDM application development, CAD/PDM system management and MCAD detailing and design, and performs software development for core SmarTeam.