Manufacturing

Digital Prototyping - Concept to Reality

11 Oct, 2007 By: Jeffrey Rowe


Despite the tremendous progress made in 3D modeling over the past 20 years, most companies continue to create physical prototypes as a major part of their product development process. For some time, most manufacturers have realized that something else was needed to move beyond 3D geometry and physical prototypes. These same manufacturers, in addition to several MCAD vendors, acknowledged that further progress in the digital design process could take place only when the 3D CAD model is extended beyond just 3D geometry to provide a comprehensive digital representation of the product -- including its physical properties, underlying engineering principles, and functional characteristics.

Although other vendors have attempted to do away with physical prototypes, Autodesk has taken a step forward in Autodesk Inventor with its Digital Prototyping tool that promotes a “test before build” approach. This process focuses on creating a digital prototype before committing to a physical design and prototypes that begin with functional requirements and specifications. Parts and assemblies are then created with Inventor to meet those specifications. Theoretically, this approach changes the balance of the design process, ideally letting engineers spend more time engineering and less time constructing 3D geometry.

Like many of you, I was skeptical of the notion and practice of digital prototyping being much more than a nebulous term and marketing hype. That is, until I heard about Richlin Machinery and talked with its president, Jeff Richlin, about digital prototyping using Inventor, translating a concept into a reality.

When it comes right down to it, most 3D parametric design technologies are not focused on the design process, but rather on the documentation process; that is, creating 2D drawings or 3D models of a product concept. Geometry is the focus of much of today’s 3D parametric design process, but documenting geometry addresses only form and fit. Design is about function. The focus on geometry is consuming and limiting aspects of most parametric design software systems, forcing users to produce designs using concepts that often do not reflect a product’s original intent or function.

Admittedly, other competing CAD packages have attempted to take an approach analogous to digital prototyping. Some have succeeded, but many have not. These attempts have included “intelligent” parts libraries and mates, wizards, rudimentary calculators, and optimization tools. Fundamentally, digital prototyping is intended to allow you to make engineering decisions first for solving engineering problems instead of having to make geometric decisions up front. This approach lets you focus on the comprehensive design, not just a model.

Richlin Machinery, a custom builder of machine tools and precision machinery (such as high-volume metal cutting and assembly machines used primarily to manufacture screws and other fasteners), is using Inventor software with its digital prototyping capabilities as its only MCAD tool. Jeff Richlin said, “We are delighted with the way Autodesk Inventor has enhanced our performance at every stage of production.”

The digital prototypes help Richlin Machinery communicate more effectively with customers during the sales cycle by providing customers with a realistic, accurate representation of the product that ultimately will be built.

For Richlin, digital prototyping starts with customers defining what they want a machine to do. He explained, “Richlin designers take a customer’s requirements, grab some parts off of the Web, sketch in some linkages, and package some of the new machine components in sheet metal.” He said this process typically takes four to five hours, and his company performs this service free of charge. The customer either accepts the functional design or Richlin designers go back through the loop until the customer’s requirements are satisfied.

Once the requirements are met, Inventor is then used to design a machine that will perform the processes a customer wants; then it is constrained and simulated. The customer gets a functional 3D model that has been proven from a purely functional standpoint to perform the customer’s processes. At this stage, Richlin will either get the go-ahead to build the physical machine or provide engineering specs so it can be built elsewhere.

Digital prototyping extends into the engineering phase, where Richlin Machinery has used Inventor to design a complete product in two to three days rather than two to three weeks. Inventor has helped the company to increase its total volume of business; it now handles approximately ten sets of preliminary designs for customers every week and is able to complete an entire project, from start to finish, in three to four weeks.

Richlin creates machines in the following three ways -- designing and building them from the ground up, designing around existing machines with accessories, and gutting machines down to the original frame and castings and refitting them with state-of-the-art CNC capabilities and hydraulics. When Richlin designs parts that must be fabricated, it tries to employ water jet machining wherever possible because of its speed compared with some other techniques.

As advanced as Richlin Machinery seems today, it wasn’t all that long ago that it evolved from being a totally non-CAD environment. As recently as five years ago, the company was using VISIO as its “CAD tool,” and before that, Microsoft Draw. Jeff Richlin realized that he had to change to the true digital design world to survive, but said he couldn’t get comfortable with AutoCAD.

However, he did say that because of this slow start, he did not have to contend with legacy AutoCAD data. So, he stuck it out with the tools he had, started shopping around for a suitable 3D tool, and picked up Inventor at the tail end of Release 10. Today, Autodesk Inventor is the only digital tool used for design at Richlin Machinery, although it imports customer data from other CAD tools via techniques and formats such as STEP and SAT.

Jeff Richlin said his biggest advantage with digital prototyping is he now uses the capabilities in Inventor to model and physically design a machine once, instead of building it two or three times. He points out that many of his old competitors that were, and still are, hesitant to make the move to 3D are no longer in the game, adding, “To remain competitive, manufacturers must spend the time and money for technologies, such as digital prototyping, as well as embrace the people coming out of school for furthering the next generation of manufacturing minds.”


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