Integrated Design

DuPont introduced the ACA IV in 1983 as a desktop analyzer for small hospitals, clinics and emergency facilities worldwide. The ACA IV was a technological landmark when it was introduced since it was capable of conducting more than 67 different tests automatically. The ACA IV was so successful that it became a flagship product for DuPont’s medical division for more than 15 years. The design was so well executed that it remained virtually unchanged throughout the product’s life which lasted well past 1996, when DuPont sold its medical businesses to concentrate on other markets. Developing a design classic such as the ACA IV requires a keen understanding of human factors, aesthetics, technology, and engineering skills which are rarely found in a design firm such as Integrated Design. This is why the ACA IV has been profiled in a case study, serving as a testament to our long history in developing products from concept to production.

IDS was contracted by DuPont’s engineering department to develop a rudimentary hand fabricated sheet metal prototype of the ACA IV into a worldclass commercial product. Although the prototype appeared to be somewhat well defined when compared to other laboratory breadboards, it required complete redesign before it could be introduced as a commercial product. Our design development began by completely analyzing the product’s intended function. This study included a study of critical alignments between internal components, internal thermal requirements, preferred assembly procedures, operator interface, overall function, and hundreds of other considerations. Information was assembled into a comprehensive report which was shared with to DuPont’s management team. The report recommended a number of improvements which ranged from human factors and overall appearance to manufacturing alternatives. Photos of the original prototype are shown in the following pictures.

Part of the research study included design proposals defining how the product could be manufactured. This rigorous task was highly challenging because of the product’s complex functionality, number of parts and unique arrangement of components. In depth examination of the product precipitated three basic design directions for manufacturing the analyzer. These alternatives were based on the weight distribution of internal components, thermal isolation requirements for the reaction chamber, and user accessibility to routinely replenished chemicals. The three alternatives are shown in the following pictures.

The first concept was based on an inner one piece molded chamber which would be mounted to a cast aluminum base and support the covers surrounding it.

The second concept segmented the product into an upper and lower set of covers forming the chamber while also providing support for the external covers.

The third and last alternative was based on individual flat panels that formed the inner chamber. This assembly would support the external covers and also be mounted to the case aluminum base. This last approach was considered to offer the least risk, lowest tooling cost and most design flexibility.

Each of these studies involved an exhaustive cost study based on each part which was designed in sketch form for a particular manufacturing process. Costs were estimated for each part as well as tooling investment. The following pictures illustrate a few of the dozens of concepts that were distributed to vendors for estimates.

After the product was methodized for production, design concepts for the ACA IV were created. These concepts were based on the integration of form and function as well as the preferred manufacturing process. Concepts were developed with certain common features. These included a clear smoked acrylic top cover for viewing the internal thermal chamber, easy access to the input sample tray, easy access to the touch panel and display as well as a sloped front for optimal operator interface.

The preferred concept illustrating the diluent bottles as exposed blow molded containers with colored labels was accepted as the preferred design. It was refined and further developed throughout the remainder of the project.

After a few months of engineering development, the design was finalized and released for production tooling. Although the predominant manufacturing process was structural foam, the base was molded in sand cast aluminum and the top was thermoformed acrylic. Numerous secondary parts were fabricated in sheet metal. The following pictures illustrate patterns and molded parts during the initial production startup. A few of the numerous molded parts can be seen in these photos.

Molded parts were examined for dimensional accuracy, overall shape and configuration as well as general appearance. The following photos show some of the numerous structural foam molded parts which were carefully reviewed with the molder and DuPont’s engineering team.

IDS supported DuPont during this preproduction phase by reviewing the initial assembly of plastic parts to the base as well as to each other. After witnessing the molding process we examined each part and assembled a unit to verify fit. All parts assembled to each other and the base as expected. The following pictures will show individual panels and how they were mounted to the sand cast aluminum base to form the reaction chamber. This production design was primarily based on the concept determined during the earlier development phase.

The results of all this work are expressed in the ACA IV which was major success when it was introduced and remained a benchmark for desktop analytical instrumentation for more than 20 years. It is still recognized as a landmark product in analytical medical diagnostics and has been emulated by many other followers. The design was so successful that it remained virtually unchanged for the product’s entire life cycle. The ACA IV has become a classic.