The objective of the Roadmap for Additive Manufacturing (RAM): Identifying the Future of Freeform Processing was to develop and articulate a roadmap for research in the area of additive manufacturing for the next 10-12 years. (102 page pdf)
Industries that will drive the market over the next decade include the military, dentistry, jewelry, entertainment products (e.g., video games), collectables, home accessories, and toys.
Two whole layer AM processes have been commercialized and two others are in the works. This type of processing is not only faster, but it may offer improvements in accuracy, surface finish, simplicity, and machine reliability.
Successful completion of the following recommendations will lead to significant benefits on affordability, maintainability, reliability, rapidity and functionality in practical applications of AM. The technologies will become more adopted by the technical community with AM expertise, but there is a great potential for catalyzing the use of AM technologies by a broad population of entrepreneurs.
• Create conceptual design methods to aid designers in defining and exploring design spaces enabled by AM.
• Produce a new foundation for computer-aided design systems to overcome the limitations of existing solid modeling in representing complex geometries and multiple materials.
• Provide a multiscale modeling and inverse design methodology to assist in navigating complex process-structure-property relationships.
• Create methods to model and design with variability: shape, properties, process, etc.
Process Modeling and Control Recommendations
• Develop predictive process-structure-property relationships integrated with CAD/E/M tools.
• Create closed-loop and adaptive control systems with feedforward and feedback capabilities. Control system algorithms must be based on predictive models of system response to process changes.
• Produce new sensors that can operate in build chamber environments and sensor fusion methods.
Materials, Processes and Machines Recommendations
• Develop a better understanding of the basic physics of AM processes to capture the complexity in the multiple interacting physical phenomena.
• Create scalable, fast line or area material processing methods to greatly increase machine throughput.
• Create open-architecture controllers and reconfigurable machine modules.
• Exploit unique AM characteristics to produce epitaxial metallic structures, fabricate parts with multiple and functionally gradient materials, and embed components during fabrication processes.
• Develop screening methodologies to answer the question as to why some materials are processable by AM and some are not.
• Develop tools for AM fabrication of structures and devices atom by atom and design for nanomanufacturing.
• Develop and identify sustainable (green) materials including recyclable, reusable, and biodegradable materials.
Biomedical Applications Recommendations
• Create design and modeling methods for customized implants and medical devices.
• Develop viable Bio-AM (BAM) processes for fabrication of “smart scaffolds” and for construction of 3D biological and tissue models using living biologics.
• Create computer-aided BAM including modeling, analysis and simulation of cell responses and cell-tissue growth behavior.
Energy and Sustainability Applications
• Design energy system components to take advantage of AM capabilities.
• Pursue Maintenance, Repair, and Overhaul (MRO) as a potential AM application.
• Develop equitable indicators for measuring sustainability in AM processes and products.
• Identify sustainable engineering materials for AM processes.
• Develop university courses, education materials, and curricula at both the undergraduate and graduate levels, as well as at the technical college level.
• Develop training programs for industry practitioners with certifications given by professional societies or organizations.
Development and Community Recommendations
• Reduce machine, material and servicing costs to ensure the affordability of AM in relation to conventional manufacturing.
• Develop and adopt internationally recognized standards (such as those recently initiated by ASTM Committee F42) which are useful to product, process and material certification.
National Testbed Center Recommendation
• Establish a national testbed center with distributed AM machines and/or expert users to leverage equipment and human resources in future research and to exemplify the cyber-enabled manufacturing research concept.
Barriers and Challenges
Aerospace companies often require a 3:1 return on its investment, meaning that for every dollar spent on AM, it must receive $3 in return to cover implementation and maintenance costs. For companies that are comparing an existing manufacturing process to AM, it is believed that many must realize a gain of at least 30-
40% when replacing the old with the new. Anything less is usually not worth the risk and hassle of replacing a proven method with one that is new and uncertain.
Cost is only one factor that influences the adoption of an entirely new process or the launching of a new business based on a new process. Time to market is another important one. Some companies are willing to pay a premium if the time savings are significant. Additive manufacturing presents the opportunity to reduce the part count in a product by consolidating two or more parts into a single design. Additionally, complex parts can often be produced in less time with AM.
Northrop Grumman has identified 1,400 parts that could be manufactured by AM for one of its military aircraft programs if the right materials were available. The challenge, therefore, is to develop AM plastics and metals, along with testing standards to ensure quality and consistency that meet the needs of leading aerospace manufacturers. Turbine blades made by direct metal laser sintering (DMLS) from EOS (a German manufacturer of laser sintering/melting systems) have found their way onto test rigs.
Direct Metal Deposition
according to Jyoti Mazumder, University of Michigan at Ann Arbor :for commercial viability and mass acceptance. Some of the issues are:
1) Deposition rate: Higher deposition rate is a must for making it a commercially
palatable process. Presently, about 6 in3/hr/kW is the limit ‐ similar to electronics
industries, our goal should be to double the deposition rate every 2 years.
2) Powder catchment ideally should be 99% or more, whereas presently, it is around 20‐70% based on the design of the 3‐D structure.
3) Online diagnostics and feedback control are a must for robust quality production. Some of the important issues include (a) repeatable deposition geometry, (b) defects
such as porosity, voids, microcracks, (c) composition control, (d) residual stress
evolution and (e) distortion.
4) Surface Finish. However, near net shape is the product from additive manufacturing
may be presently possible, but it still needs some post‐processing to bring it to
mirror (υm) finish. A system which can achieve mirror finish will widen the market
for molds, etc.
5) Control of internal geometry: Conformal cooling for energy conservation and lead time reduction. Additive manufacturing can offer many a functionality for a designed product. For example, in the pixel by pixel manufacturing of a product, using additive manufacturing, one can create a cooling line in a mold which conforms to the shape of the product that the tool will be making. A recent study with a global company revealed that a particular set of 5 tools can save the company 23 billion BTU/year. Additive manufacturing can be effectively used for conservation of energy during manufacturing leading to a significant reduction of the carbon footprint. Manufacturing is responsible for 33% of the world’s carbon footprint. The scope is enormous.
6) Patient specific biomedical products: Synthesis of a CT scan with additive manufacturing for rapid prototyping biomedical products such as prosthesis, scaffolds for regenerative treatments, etc. This will enable accelerated recovery of wounded people, and products can be patient specific. Recent work at Michigan demonstrates patient specific bone by inserting the genes harvested from the bone marrow into the scaffold. Within 6 weeks, scaffold was covered with bones grown from the genes. With recent freedom of research in stem cells, who knows where we can go. I can foresee additive manufacturing systems in the field hospitals or emergency rooms where quick prosthesis or scaffold can be generated for speedy regeneration limiting human agony and medical expenses.
Electron beam freeform fabrication
The buy to fly ratio is the mass of material that is require to machine a part compared to the mass of material in the finished part.
Ryan Wicker, University of Texas at el Paso, works on Direct Digital Manufacturing (DDM). Wicker’s group and Brent Stucker’s group at Utah State developed a flexible and mobile fused deposition modeling (FDM) manufacturing system that can deposit material on virtually any surface. This new machine has been integrated with an ultrasonic consolidation (UC) machine and used to dispense support material for UC fabrication as well as a potting material for embedded electronics so that the combined processes can produce fully functional integrated electronic systems. The development of integrated technologies for fabricating 3D electronic systems is a focus of my group, and I believe represents another significant opportunity for growth of our industry. It is interesting that a “printable/flexible electronics” industry already exists (in the ~$10B range), and this industry has by and large emerged from the electronics fabrication industry — I believe both industries can benefit from cross-fertilization (especially since some industry estimates in “printable electronics” include revenues in excess of $100B and possibly up to $300B by 2025.