Case Introduction

Armed with FEA and other 3-D design tools, manufacturer is free to push design concepts without the cost and labor associated with building physical prototypes.

For 140 years, A.T. Ferrell Company has manufactured the grain cleaners, sifting conveyors, roller mills, and steamers that farm operators, feed mills, and food, cereal, and oilseed processors use on a daily basis to bring food and agricultural products to market. The machines and tooling structures are huge and often custom configured. Many in the company affectionately use a Mr. Potato Head metaphor to explain the A.T. Ferrell product development process, as it is possible for a single machine to be brought to life in seemingly endless combinations, depending on customer need.

Yet all that variety—not to mention the sheer size of the custom-configured machinery—posed obstacles for A.T. Ferrell engineers as they worked through the development process to zero in on optimal designs.  Producing physical prototypes for all the different variations was costly, requiring a team of designers, engineers, and production personnel to assemble and test each trial machine and determine what worked and, more important, what did not. Space was another issue because the engineers were limited in terms of how many of those physical prototypes they could build and accommodate in the confines of the plant floor.

Three years ago, A.T. Ferrell began an active campaign to address these challenges by transforming its physical prototype process into a digital one. Instead of Ferrell being limited to a handful of design possibilities, a digital prototyping approach would let design teams explore myriad options and pave the way for computer-aided simulation —specifically, finite element analysis(FEA)— to be incorporated into A.T. Ferrell’s engineering workflows. The changes would give the engineering teams more freedom to push design concepts and allow them to identify and address potential problem areas far earlier in the development process. The engineering group also would take steps to put processes and software platforms in place that would allow it to capture and save design iterations for reuse on subsequent products. The ultimate goal of A.T. Ferrell’s transformation: to make more competitive products at lower cost while accelerating time to market.

Fit and Function

The first step in the digital prototyping journey was to leverage mechanical computer-aided design (MCAD) tools, in this case, Autodesk Inventor, to create 3-D models of the machinery as well as to leverage Autodesk Vault Workgroup to manage design data. Although 3-D MCAD streamlined much of the drafting process, the models did not accurately reflect the fit and function of the various designs. Without additional information, it was hard to determine, for example, whether this was the best possible design: exactly how individual components would perform or whether the different assemblies would come together properly to meet safety requirements and achieve the expected reliability. To fill in the gaps, the teams built physical prototypes to test and refine each concept, a process that limited the number of possibilities they would explore for each project.

The limitations of the traditional engineering practice became obvious during a project for a roller mill system in which the customer required a higher amount of pressure than was applied normally. The engineering team quickly realized that its standard materials choices were likely to fail under the newly specified conditions, thus requiring a significant design change. This time, instead of traditional trial-and-error guesswork, the engineers decided to expand their CADuse and enlist FEA capabilities to explore and test different design and materials scenarios digitally instead of building physical structures. As a result, they were able to perform stress analysis simulations on 15 different digital design options, eventually zeroing in on a specific combination, which they then validated with help from an outside analysis specialist. With the digital prototyping method combined with FEA, it took one engineer only two days to complete this process. In contrast, the engineer would have been able to explore only a handful of design possibilities with the traditional approach, and it would have required participation from up to a dozen people, including design engineers and manufacturing production personnel, and taken weeks to build physically, test, and evaluate the different options.

After their initial success, the design teams regularly began to enlist FEA when appropriate. Unencumbered from the cost and labor of building physical prototypes, the engineers were more apt to refine machines proactively and continuously improve components that they otherwise might have left alone. In addition, because the what-if exploration is conducted in the digital world, there is little risk associated with exploring new ideas, enabling A.T. Ferrell to experiment freely with designs it never would have been able to entertain previously. In addition, FEA allows the team to apply forces and stresses to determine how much material it really needs, a process that has led to reduced materials and energy costs. The teams are also better able to address regulatory requirements—for example, OSHA regulations—much earlier in the cycle so that there is no last-minute, high-cost retooling of designs to accommodate the safety requirements of equipment for workers. Finally, the digital prototyping approach generates additional time and cost savings in that the same digital model is used to generate technical support documents and service manuals as well as sales and marketing materials.

One Step at a Time

Although it took some effort to integrate the changes into A.T. Ferrell’s engineering workflows, it did not require a wholesale sales pitch to get buy-in from top management or individual engineers. The colored charts and graphs produced by the FEA tool indicating potential material glitches or design flaws were strong enough proof points for management to green-light additional simulation software and services contracts. The engineering team also did not bite off more than it could chew. It started out using FEA and digital prototyping on a specific component or group of components, performing analysis and interpreting the results on a small scale. As the process became familiar and the benefits of the results became apparent, interest in the new way of working escalated and engineers began to ask to be trained in the new disciplines.

Another way A.T. Ferrell ensured success with its FEA efforts was by keeping a trained simulation expert in the loop. Although engineers could test and validate designs on their own with the CAD tool’s built-in FEA capabilities, they were not trained sufficiently in the science to interpret their assumptions properly and ensure that the results were accurate. The team made sure to send out its findings to an outside analysis services expert to validate the results before moving ahead with any development efforts. That trend is likely to continue as more mainstream engineers—not analysis experts—tap into FEA to test their own digital designs. Additional time and cost savings were achieved by narrowing the optimal design in house and sending out only the final version to be verified by outside services.

Although employees are often resistant to any variation in work style, A.T. Ferrell encountered little resistance from engineers in making the transition to digital prototyping. By keeping the lines of communication open and making the changes in small steps as opposed to one fell swoop, the company was able to infuse the transformational change that was necessary for moving along the digital prototyping path.