Deere & Co., the Moline, IL, agricultural equipment giant, has been using rapid prototyping (RP) for about a decade, and is now finishing a wider examination of its entire product development process. Deere is seeking to cut development time by as much as 50 percent, and is looking at how the different prototyping techniques can help that along. Using solid modeling software, as Deere did, is critical for engineering teams wishing to use RP technology. Deere has expended considerable effort recently developing a new product-delivery process (PDP). Such processes can be difficult to hammer out and then follow faithfully, especially in today’s work environment of lean staffs and greater profit pressure. Although RP materials have improved significantly since the first stereolithography machine came into use a little over 10 years ago, none of the current materials to date have the durability required for use on John Deere products sold to customers.

## Article

Throughout the 1990s, engineering departments and divisions worldwide have been acclimating and refining the processes of rapid prototyping. New methods have come to the fore, and the cost of the original methods has come down dramatically. Systems have even made the proverbial march to the desktop.

Deere & Co., the Moline, Ill., agricultural equipment giant, has been using RP for about a decade, and is now finishing a wider examination of its entire product development process. Deere is seeking to cut development time by as much as 50 percent, and is looking at how the different prototyping techniques can help that along.

We talked with John K. Lawson, Deere's senior VP for engineering, information, and technology, about RP and the engineering process.

Lawson reports that rapid prototyping of physical models has been important in Deere's product design cycle, but today the role of virtual prototyping—that is, computer modeling-is growing faster, and the company is finding advantages in working with computer models at ever-earlier stages of design.

Senior VP John K. lawson of Deere: "We move from solving problems to preventing them."

## Proving Rapid Prototyping's Worth

John Deere has been using what is commonly referred to as rapid prototyping to produce physical models since 1990. At that time, the new technology was seen as another potentially valuable tool to improve the development of John Deere products, Lawson said, but its worth had to be proved. Deere executives recognized that RP, like many emerging technologies, would evolve and develop over time, that some of the processes would mature into a lasting, robust technology, and others would disappear. With this in mind, Deere decided not to in- vest in the ownership of RP equipment, but opted instead to purchase RP models and replicas from outside service bureaus.

Deere appointed an RP facilitator to introduce the new technology at various product development sites, to assist specific design teams in rapid prototyping, and to conduct in-house seminars. The approach enabled Deere to involve about 200 designers, engineers, and other design-team members in the use of RP during the early 1990s.

Since Deere had decided not to purchase RP equipment, a sm60th transition from in-house engineering to the service bureaus was important. Integrating a computer modeling program-in this case, Parametric Technology Corp.'s Pro/Engineer-into the design process made it easier for designers to order RP models from the company's outside supplier.

Using solid modeling software, as Deere did, is critical for engineering teams wishing to use RP technology, according to Terry Wohlers, an industry consultant and analyst based in Fort Collins, Colo. Nearly all RP systems start from a stereolithography (STL) file, which is the de facto standard format for RP systems and is supported by almost all CAD programs. These STL files must be what Wohlers terms "watertight," so the RP system does not choke on holes and gaps in the data.

Lawson said that only in the last year or so has John Deere purchased any equipment for in-house building of physical RP models. Now, one Genisys desktop machine from Stratasys and one Actua 2100 desktop modeler from 3D Systems are in use at Deere's Product Engineering Center in Waterloo, Iowa, where tractor and engine design teams are making concept parts. Another Genisys machine, at the Deere Technical Center in Moline, has been used as a more centralized source by different product-design centers.

Deere engineers exploited their CAE software, including PTC's Pro/Engineer, to virtually prototype the components of this tractor control panel.

## Establshing Engineering Procedure

Deere has expended considerable effort recently developing a new product-delivery process (PDP), Lawson said. Such processes can be difficult to hammer out and then follow faithfully, especially in today's work environment of lean staffs and greater profit pressure. But for the same reasons, a clear process that everyone follows is vital.

The Deere process is "a structure that defines the steps and approvals that are necessary to develop a new product," Lawson said. But the process does not enumerate how many engineers or how much time each step can take. Products provided by the four Deere equipment divisions vary considerably in their complexity and size, he said, so for this and other reasons there can't be specific time frames or manpower limits for product development.

"In a very large complex product PDP, we may have as many as 75 engineers over a period of three to four years," he said. "A smaller program may have 10. engineers and be complete within nine months." In the end, Deere wants to examine the product development cycle and then shorten it by 30. to 50. percent. Of course, Lawson said, the reduction in time has to occur along with improvements in product and process quality.

The first steps of the product delivery process break out in this order: strategic business planning, in which the customer and market are the first consideration (an engineering maxim); program definition, where potential design and manufacturing concepts are laid out; concept evaluation and program specification; and program development, when detailed design and development are finished.

In the fifth stage, confirmation and implementation, the manufacturing prototypes are made on the assembly line. The product delivery process is in a continuous sixth-and final-stage during manufacturing and delivery, when feedback is gathered for continuous improvement.

It is the fourth stage, program development, where rapid prototyping often falls, though Wohlers, the industry consultant, argued that engineering time is reduced an order of magnitude for each stage earlier in the game that RP is brought in.

Deere has found that earlier product design pays dividends, but not with rapid prototyping as much as with virtual prototyping, which is made possible by the latest CAE software.

According to Lawson, the development work with "hard prototypes" is typically done in the fifth phase, confirmation and implementation. "If we develop complete virtual prototypes in phases two and three," he said, "we move from solving problems to preventing problems."

However, brand-new technology requires a second protocol. "We are in the process of developing an enterprise tec hnology delivery process," Lawson said. "We have found that developing new technology must be done outside of a product PDP. And that TDP must be complete before inclusion in a PDP."

The technology delivery planat Deere includes technology identification, research, assessment, and development. The concept is to use only "proven" technology in product programs.

Components of this John Deere 8000 series tractor panel were rapid prototyped during the design phase.

## Building Fewer Prototypes

In some instances, advances in software appear to be presenting a serious challenge to the rationale for rapid prototyping. "At Deere, products are often quite large and involve various metal castings, sheet metal welded components, and plastic parts," Lawson said, "so what is commo nly referred to as RP-stereolithography, selective laser sintering, laminated object manufacturing, and soon-can only be applied to a portion of our designs."

As the product delivery protocol indicates, "We are moving toward electronic-design iterations, using product visualization software and virtual reality," he said, "and we are building fewer physical prototypes."

Whether a particular part is suitable for RP, or needs to be prototyped at all, is a decision left to members of the specific design team. "With Pro/Engineer as the foundation for our designs, it really makes no difference to the designer," Lawson said. Again, that 's beca use the Prol E files are easily transferred into RP-suitable STL files. The cost model is encouraging the drive away from physical prototypes and toward virtual prototyping, also. Most common full-size, robust RP machines, fully installed, cost $300,000 to$500,000 each, Lawson said.

"And in order to match specific part needs with the most suited technology, you might have to spend over a million dollars, in addition to the cost of a climate-controlled room, auxiliary equipment, and so on," he said. The number of physical models being built each year, even at a large company like Deere, "would not justify such expenditure."

## 'Desktop-Like' Systems

So, Deere employs a few of the new" desktop-like" systems and uses the mature process in place for sending CAD files out to an RP service bureau when that is deemed necessary. But th e emphasis is on virtual prototyping.

Lawson brought to light one reason that rapid prototyping has reached this more mature stage. RP still cannot be small-lot computer-aided manufac turing, because "the RP equipment does not yet produce a part with true engineering material properties and with the speed and cost near that of CNC machining, injection molding, or other manufacturing processes," Lawson said.

Although RP materials have improved significantly since the first stereolithography machine came into use a little over 10 years ago, none of the current materials to date have the durability required for use on John Deere products sold to customers," he added. In several isolated cases, RP components have been used for short-term field testing.

There are a number of ways that the field of rapid prototyping can broaden. Expect a greater number of options th anever, especially in software. And, as Wohlers has reported, expect to hear that engineers from service bureaus are expanding their capabilities to be sure they can continue to service the greater engineering community.