Questions and Answers – AAPT
Q1. Can you say whether the targeted application is heat exchangers? The canonical features of interest point to this conclusion.
A1. It is one of the application areas of interest, but the call is not limited to heat exchangers. Showing an understating of performance limits of the features in question would demonstrate an understanding of the problem space.
Q2. Can you elaborate on the mechanical properties desired? Specifically, temperature, strain-rate effects, and fatigue (LCF/HCF)?
A2. Strength, temperature, Low Cycle Fatigue (LCF) and high cycle fatigue (HCF) i.e. are the ones typically used as screening properties to identify mechanical trends and identify the efficiency of HIPed vs no HIPed. It is suggested to not solely focus on strength properties; a range of approaches within scope and schedule would be ideal.
Q3. Are you interested in the surface effects of smoothing on fatigue?
A3. No, the intention is to understand the limits of the as-built surface, if the proposal demonstrates it requires surface smoothing that would be seen as allowable, but the AF is not interested in the project team consuming resources to survey different techniques.
Q4. How thin is thin and how narrow is narrow? Are you interested in the limits of thin walls or narrow channels that can be fabricated or addressing RFP issues for larger, easier to fabricate features?
A4. Canonical features, standard features are thin walls, relatively tight radiuses, and passages of fairly narrow dimensions that could have pressure or flow requirements. It is not necessary to push the absolute boundaries of fabrication, but 0.010 mil wall thicknesses are achievable and suggest scaling up from there as appropriate.
Q5. Are there any specific (or high priority) applications under consideration for the canonical features?
A5. The applications of features themselves are typically what a thin wall itself would do in normal operation. Whether that’s lightweighting, heat transfer, or pressure retention or potentially all three.
Q6. Does a research group need to have their own nickel-alloy-capable AM equipment?
A6. No. This project call is not calling for process development to optimize parameters.
Q7. Do you envision concepts/proposals addressing all 3 nickel materials (625, 718, 230) or a single selected material?
A7. Either solution is possible, but caution that three could be a challenge in terms of scope. Depends on range of properties the team chooses to address; focusing on a single property is unlikely to provide sufficient confidence. The results should provide authoritative and confident data.
Q8. Is there a minimum wall thickness/feature size within scope?
A8. The starting point should be approximately 0.010 mils, but there is no lower limit if the team is confident in fabricating reproducible features. However, experience states wall thicknesses lower than 0.010 mils start to lose material integrity issues.
Q9. What range of thin wall thickness and narrow passage diameter are you interested?
A9. Wall thickness see answers 4 and 8. For narrow passages, propose whatever your experience is, 0.015-0.020 mils is achievable with difficulty.
Q10. Is there interest in process parameter manipulation to mitigate the debit (if it can be done within budget/time)?
A10. We are seeking proposers to utilize currently established parameter sets and to examine the debits associated with the identified features. If an approach proposed some baseline optimization, that may be acceptable, but the real focus should be on currently established parameter sets. It is a technical risk to approach an optimization methodology.
Q11. Who is the end customer/user for the design curves that will be generated?
A11. DoD and America Makes are the sponsors, so generally speaking DoD and America Makes Members.
Q12. What rules apply to solid metal block support interfaces? “As-Built” implies broken off supports with stubble left behind?
A12. “As-built” means it doesn’t receive extensive surface finished improvements. Avoid using methodology not current employed and not feasible for some of the features in question.
Q13. Will this webinar be recorded and made available?
Q14. Who can be the lead organization?
A14. Any America Makes Member.
Q15. Are you interested in corrosion performance of nickel alloy at high temperatures? Are you interested in varying material properties to decrease surface roughness of as-built surfaces?
A15. Not extensively. The reality is rough surfaces are relatively rough upward and smoother downward. Surfaces are rough, so assessing the realistic and common ranges is important. If a small portion of proposal wanted to explore looking at improved surface and use as baseline may be useful but the essence of the project is dealing with surfaces we know are going to encounter. Also, HIP vs No HIP is an important part of this program. Real challenge would be combing those two.
Q16. Should narrow passages be opened or closed on top?
A16. Both, but there must be access to the passage. Enclosed volumes with no powder egress is of no interest.
Q17. One of our partners wants to use a machine at a foreign facility (in this case, Sweden) in support of the proposed work. Is that acceptable?
A17. Foreign members with sites outside the US can use foreign resources but no federal monies can be spent outside the US. Also, they will be governed by the foreign process and ITAR / EAR of how data is handled between the US site and foreign site. Project Leads and team members will have to ensure they are adhering to the America Makes Foreign Membership agreement.
Q18. Can accumulated cost share from previous projects be applied as cost share for this RFP?
Q19. One of our partners is not an America Makes member and is considering joining – can they cite future membership fees as cost share?
Q20. Would a scope that focuses on thin walls alone, without consideration of channels or other features be considered as cause for rejection?
A20. Thin walls alone could constitute a fine proposal if the depth of technical evaluation was authoritative.
Q21. I have a question about the America Makes project requirements. We have been invited to be a sub contractor to a member of America Makes. I am aware that as a sub we are not required to be a member with the associated fee requirement (Platinum, Gold, Silver). However, what are the requirements around cost share. Is a 50% cost share a requirement as a sub, or does it depend on the wishes of the associated America Makes member project lead
A21. The Project Lead will determine the project team members breakdown to ensure the team meets the 50% cost share requirement. The total project cost share can come from 1 or all sources.
Q22. Is cost share a “straight dollar for services” methodology or may it also extend to an in-kind contribution of hardware, software or a combination of both systems?? Is there available documentation online to provide guidance on this particular subject?
A22. In-kind contributions are allowed provided they meet the requirements found in CFR 200.306.
Q23. What does ‘technology transition’ in the concept document entail? Could you please elaborate?
A23. There are a number of questions in the Concept Tool which are related to Technology Transition, please address those specific questions.
Q24. Other than papers, conferences and working with SDOs, does working with an university to develop and incorporating in an additive manufacturing course curriculum include technology transition?
A24. Yes, as long as there is benefit to the targeted community.
Q25. Concept document asks which critical technology element (CTE) the project address. Could you please specify what the distinctions are between the different elements?
A25. There is a high-level description of the Roadmap Swimlanes found here: https://www.americamakes.us/our_work/technology-roadmap/ additional detail on the CTEs is located in the Digital Storefront.
Q26. I was just reviewing the latest AM calls. It seems like the cost share for these is less than for prior projects. Any visibility to why this is?…
A26. Every project and project topic is assessed with our public partners for what shared risk in the form of cost share is required.
Q27. The RFP states…NCDMM and AFRL seeks proposals to address:
Quantify the mechanical performance debit of using as built SLM surfaces to fabricate high temperature nickel alloy canonical features such as thin walls and narrow flow channels.In the statement above you call out SLM surfaces. Are we restricting the type of system the proposers can use? Does it have to be an SLM solution or could a proposer include any DMLS solution?
A27. “SLM” refers only to the ASTM F42 term Selective Laser Melting and not the tradename of a machine vendor. Any selective laser melting machine (laser powder bed fusion) is equally viable. However, electron beam systems are not included.
Updated: August 11, 2018