Hybrid manufacturing case: Rosendahl Nextrom

Rosendahl Nextrom approached Etteplan AMO team with a challenging case. The aluminum component in question operates in a hostile environment, with temperatures exceeding 1000°C. In order to ensure that temperatures within the component remain below its melting point, channels for cooling water must be integrated into the part. An earlier design for this part consisted of a complex structure requiring 8 manufactured components, 11 welds, and machining after each individual weld. This first design was very difficult to manufacture and was not feasible for production. The goal of the redesign was to utilize additive manufacturing (AM) where needed to improve manufacturability and reduce the number of welds and components, while simultaneously achieving a similar level of cooling within the product.

Design for Manufacturing and Assembly (DFMA) is a design methodology that can be used to simplify a product structure, reduce manufacturing and assembly costs, and lead to more efficient manufacturing practices. DFMA and its more efficient offshoot Down-Costing (DC) methods have been offered as services and as training for engineers by Etteplan for 15 years, with more than 40 engineers trained internally and an additional 60 trained among our key customers. The DFMA approach was particularly useful in the customer case described here as the final product would inevitably have a complex structure and a large number of design objectives that needed to be balanced with manufacturability. 

The redesign project started with an in-depth study of the function of each part within the assembled component, and then by matching those functions to stated requirements. Once the functions and requirements were clearly understood, part consolidation and potential manufacturing approaches were considered as initial design concepts were developed. In addition, all potential IPR conflicts were noted and avoided.  

A summary of the manufacturing approach for the new design can be seen in Figure 1.  Additive manufacturing was used to produce the main body of the component as well as the two identical end pieces, each of which had internal channels that could be simplified with improved flow of the cooling water when AM was utilized (see Figure 2). Some surfaces on the printed parts were machined immediately after printing. Two simpler parts were produced on a lathe and then welded to the main body before key surfaces were machined to meet requirements. The final assembly of the component was completed by bolting the three welded and manufactured parts together. The finished component is shown in Figure 3.

By using hybrid manufacturing and following the DFMA approach, Etteplan was able to design a complex structure that was manufacturable and achieved all of the project goals provided by the customer, Rosendahl Nextrom.  The new design reduced the number of manufactured parts (8 → 5), welds (11 → 2), machining cycles, and mass (5.8 → 4.3 kg).  In addition, the integrated cooling channels successfully reduce the temperatures so that this aluminum component can operate in an environment where temperature exceeds 1000°C.