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Rapid Prototyping Technology Advancement (RPTA) II

The RPTA program was an ambitious and successful undertaking for both the industrial and Depot partners. During the decade of the 1990’s, rapid prototyping (RP) technology was deve­loping rapidly and was initially regarded as suitable only for development activity, such as concept models. However, by the end of the decade, industrial users were going beyond just concept models into areas of rapid tooling and functional part experimentation.

The RPTA program applied technology to newly identified Depot applications, using commer­cially available RP machines and technologies, and technical training and assistance to gain proficiency in using the machinery and various technologies.

For example, RP technologies offer the opportunity to make prototypes and parts in diverse materials such as plastics, metals, ceramics, and composites, all of which can be found in different departments within any Depot. The technologies can also be used to avoid the lead time and expense of complex tooling for short-run replacement parts that are no longer available through any acquisition means. Participating Depots and other Government partners shared their unique needs with the NCMS industrial team partners and together all searched for a best fit with an appropriate RP technology solution. In several case studies, varying types of technologies were applied resulting in multiple parts or tools being made from a variety of materials enabling a Depot to evaluate alternatives as well as to consider more than one type of RP technology for potential implementation.

Benefits can be measured in many ways. Frequently, benefits are defined only in financial terms. Another type of benefit can be less tangible or definable, but be more far-reaching, such as the establishment of cooperative relationships between the Maintenance Activities that promise to generate beneficial outcomes for the DoD for years to come. One such significant outcome of this collaborative program occurred as an outgrowth of the culture of cooperation that was established between industry and Government users and DoD Maintenance Activities, and even more importantly, among the Depot facilities themselves. One outstanding example can be found in the following case study included here:

Steering/Diving Cast Housing Collaboration for Portsmouth NS

This effort clearly demonstrated the synergy of the RPTA team and especially that of the participating Maintenance Depots in collaborating to solve one Depot’s problem. Their relationship continues to this day in support of the design, pattern-making and casting of submarine components. As a result of this RP case study, lead times for castings were reduced and the requirement for costly tooling eliminated. Further, in support of their demonstrated commitment to the use of digital data and RP technology for the manufacture of small quantity parts, the RPTA team placed multi-jet modeling (MJM) RP equipment at both TRF Kings Bay and NFPC Philadelphia to enable them to continue to support internal DoD Maintenance needs such as was pioneered in the following case study. 

• Problem/Challenge: Portsmouth NS overhauls several SSN 688 Class submarines. Several housings of steering and diving components were cracked and there were none in the supply system. The housings are made from cast aluminum; however, tooling to produce sand castings or the patterns necessary to produce investment castings were not available. Significant time and cost was involved if either of these approaches was pursued to make replacement housings.
• Solutions/Results: It was the synergy between three Depots, assisted by the industrial partners that created the solution. The team used RP to deliver patterns directly to the NFPC Philadelphia, internal Navy capability to reverse engineer, develop patterns, and cast the parts in support of the SSN 688 CL overhaul requirements.
• Benefit/Impact: Reduced cost and lead time. Gained self sufficiency in obtaining long lead time cast parts through collaboration between Depot activities. Portsmouth NS had the requirement for the cast housing. TRF Kings Bay contributed their digital modeling capability and their ability to make RP MJM of wax patterns for the foundry. Additional team members made other models such as stereo­lithography (SLA) and selective laser sintered (SLS) to enable the foundry at NFPC Philadelphia, to work with a range of RP patterns and examine alternative casting methods.

Projected cost avoidance was realized as a result of insertion of RP&M technologies starting with the very first two DoD Depot facilities, TRF Kings Bay and OC-ALC. The success of these initial applications began a wave of interest within the Depot community to explore the appli­cability of RP&M technologies for their facilities. Cost avoidance is typically derived from the following advantages afforded by RP&M technologies:

·   50–75% cycle-time reductions for part repair and replacement

·   50–75% raw material and labor cost avoidance

·   Overhaul related design corrections reducing repair cycles.

Estimates of cost-avoidance by the participants exceeded $2.5 million for the program.

Program Manager: Connie Philips, (734)995-7051, conniep@ncms.org