The ability to bring clean air to large spaces and workpieces has been a significant breakthrough for manufacturers whose work involves hazardous air pollutants such as hexavalent chromium, isocyanates, and volatile organic compounds (VOCs). Portable enclosures serve as an all-in-one sanding, coating, and painting booth where workers simply change filters for each task.
But for aerospace and defense (A&D) contractors, it can be difficult to balance the movements of large workpieces requiring many operations without creating backlogs. Contractors increasingly need flexibility to do surface prep, sand, paint, and coat in the same area simultaneously. So, Duroair has taken its engineering ingenuity to a new level by designing a multi-chamber booth that accommodates up to three separate clean-air operations simultaneously.
Each chamber has the patented six-stage DuroPure™ air filtration system. The three chambers can be used independently, or interior walls can be removed to perform one or two functions. The enclosure can be accessed from the front or the side, and the unit can be fixed or retractable on wheels.
How the DuroPure™ air filtration system works
DuroPure™ industrial air filtration technology captures more than 99% of particulates and exceeds EPA and OSHA requirements. The unvented recirculating solution doesn’t require ducting or make-up air. It places less expensive filters in front of more expensive, technically advanced filters for protection and longer life.
The first three stages capture particulates to less than one micron. The third stage filter can be changed to accommodate MERV 15, HEPA, and NESHAP 319 standards, providing the manufacturer with the flexibility to do different operations. The final three stages are a gas filtration process before the clean air is recirculated back into the shop space.
Solutions for compliance, flexibility
Duroair’s clean air solutions cost less to build than traditional systems that require a permanent footprint and venting and can be costly if a facility is at its EPA limit for exhaust stacks. Duroair solutions can be installed within days and weeks – not months – and can be retracted in hours and moved or stored in a fraction of the space.
The clean air solutions also offer A&D manufacturers flexibility for 3D printing and additive manufacturing (AM) to radically reduce the number of parts or design complexity and assembly, reduce costs, save time, and increase scale of production.
Duroair’s retractable clean air solutions bring clean air to the workpiece and help you:
Avoid disrupting adjacent manufacturing or maintenance operations
Save material handling costs
Reduce or eliminate outsourcing
Find agile ways to safeguard critical tasks without impacting productivity
1) What new, innovative technologies has Greenleaf introduced to increase productivity when machining aerospace components?
Earlier this year, Greenleaf launched the XSYTIN®-360 line of solid ceramic end mills. We took our successful XSYTIN®-1 phase-toughened ceramic material, already very well known throughout the aerospace industry, and used that as the base material for XSYTIN-360. Our ceramic material, unique cutting geometry, and edge prep combination provides up to 10x the productivity and tremendous cost savings compared to carbide end mills. As new materials and new machines require faster cutting parameters in a more abrasive environment, XSYTIN-360 is the answer.
Greenleaf also recently introduced G-9610, a titanium turning grade that uses a unique coating process that provides a very smooth, lubricious coating. Coupled with a sub-micron substrate, it offers increased performance in the semi-finish and finish turning of titanium alloys. This additional carbide grade provides aerospace customers with a new weapon that will offer marked improvements in productivity.
2) What are typical applications for XSYTIN-360?
These ceramic end mills can be run in a broad range of workpiece materials including high-temperature alloys, hardened steels, ductile cast irons, and compacted graphite iron. Applications such as periphery milling, slotting, pocketing, ramping, and profiling are common for these end mills. The toughness of the XSYTIN-1 material allows the end mills to have a much broader speed-and-feed operating range, allowing them to run on various machining centers with increased productivity. These are extremely versatile tools that change the game when it comes to overall value in high-performance end milling.
3) What are XSYTIN-360’s operating parameters?
In heat-resistant super alloys (HRSA), these ceramic end mills typically run between 1,300 surface feet per minute (sfm) and 2,000sfm, compared to traditional carbide end mills that run 150sfm to 200sfm. In certain milling applications, we can feed these end mills in the range of 0.0014 inches per tooth (ipt) to 0.0044ipt, which significantly increases material removal rates. There are tremendous opportunities to improve productivity and reduce tool consumption with XSYTIN-360.
4) What are typical applications for G-9610?
G-9610 was designed for semi-finish and finish turning applications in titanium alloys. Many components in aircraft engines use titanium because of its high strength and low weight, but this material can cause issues when manufacturing these components. G-9610 has proven to be more resistant to build-up edge, chemical and abrasive wear, and loss of hardness at high temperatures – common issues when machining titanium alloys. This grade also performs well in the finish turning of nickel- and cobalt-based HRSA materials.
5) What are the G-9610 operating parameters?
Titanium machining capabilities vary by the phase and alloy. G-9610 can be applied at speeds from 195sfm in semi-finishing beta or near-beta alloys to 360sfm in alpha phase alloys. In alpha-beta alloys such as Ti-6Al-4V, this grade is capable of semi-finishing at 230sfm and finishing at 295sfm. When G-9610 is applied with high-pressure coolant, these speeds can be increased by an additional 20%.
There are many benefits for using wireless gages, whether as a gage only or with an advanced data collection system – a process gaining acceptance and momentum for the highest levels of quality control.
1) First and foremost, wireless measuring tools eliminate the need for bulky and cumbersome hardware such as backpacks and cables which can be safety hazards.
By eliminating backpacks and cables, there’s less equipment to purchase, startup costs are decreased, and related maintenance requirements are reduced within the manufacturer’s tool calibration program.
2) Collecting and transmitting measurement data is faster and less error-prone, facilitated simply by measuring and pressing a button to send data to a mobile phone, tablet, or PC.
This way, operator subjectivity is removed when manually transcribing data. The time spent manually recording data is no longer a concern. In addition, wireless tools eliminate any recording measurement errors from manual entries. In simple terms, wireless provides speed, convenience, and ease of collecting and storing data.
3) Wireless precision measuring tools are engineered for efficient data collection for a wide range of end uses.
Whether for International Organization for Standardization (ISO), government, aerospace, medical requirements, or smaller shops, the need for accurate data is crucial for traceability to demonstrate qualified parts or to trace any manufacturing errors. Accurate measurement data provides assurance for the end user and insurance for the manufacturer.
4) By using wireless tools and an advanced data collection software system, data can be efficiently integrated into ERP/ MRP programs.
Also, wireless gages promote a cleaner work environment by removing the need for a log journal and pens/pencils, making an ideal setup for lean manufacturing.
5) Quality control is the last step when producing manufactured parts, so if a bad part slips by, it can result in problems in the final product assembly or final product.
Using wireless precision gages, inspectors can measure with confidence to qualify the part. With a simple push of a button, measurement data is stored for future analysis or history purposes. The time and money saved by going wireless and implementing a data collection system is incomparable. Digital calculators are available that can demonstrate that.
With Internet of Things (IoT) and Industry 4.0 being the omnipresent new paradigm in manufacturing, increasing the speed, amount, and accuracy of data generation is critical. Precision measurement data acquisition/collection for quality control applications benefits significantly from wireless and mobile retrieval. Wireless Data Collection systems, such as those from Starrett, should be mobile, exceptionally robust with levels of encryption/protection, suitable for multiple needs ranging from unrestricted distances and gage compatibility, and easy to use and integrate into automated manufacturing operations. Solutions should dramatically increase productivity, reduce errors, provide full documentation, and automate the acquisition process.
Developing new fluid control components used to be an entirely manual process. Engineers conceived a design, detailed part and assembly drawings, and fabricated prototype parts. The component was assembled and tested, with the resulting performance compared to the desired specifications. The engineer and technician would then tweak or alter the dimensions of critical parts to align performance of the prototype to design specifications. It was often hit or miss, which consumed substantial time and cost until the prototype’s performance met the specifications. Once satisfied with the performance of the first prototype, several second-generation prototypes were assembled and evaluated. Frequently, their performance differed from the original prototype. More time and money was spent retesting the prototypes with modified or new parts until performance met specification.
In contrast, today’s virtual digital technology takes the guesswork out of the equation, greatly reduces the design and development timeline, and minimizes related costs in new product creation. Using digital iterative design accelerates the design process, controls costs, and yields a substantially better valve in performance and value. By the time a prototype is built, engineers are confident its performance meets spec or is close.
Valcor Engineering uses a virtual digital process known as model-based systems engineering (MBSE) that lets engineers execute a complex electromechanical systems design by creating a digital twin of the valve. MBSE can design and evaluate the performance of fluid control components before a single part is fabricated.
Historically, sophisticated mathematical modeling and simulation capabilities required high performance computing (HPC) systems such as Cray supercomputers available only to a few national labs, academic research institutions, and Fortune 500 companies. Today, the tools that enable MBSE are readily available to most companies; Valcor relies on these tools to design and create new fluid control components for demanding applications.
EMag model of magnetic flux field.
The design process
To create a new solenoid valve, Valcor engineers start by using SolidWorks CAD/CAE 3D solid modeling software by Dassault Systèmes. The software’s 3D modelling feature establishes the critical part dimensions the new valve requires and evaluates how they all fit together.
Once the parts are designed, engineers use Ansys finite element analysis (FEA) software for evaluation. The FEA process for each critical part of the assembly ensures that it’s robust and appropriate for service in the new valve. FEA identifies areas of unacceptable stress, as well as areas with dimensional weaknesses. The FEA process is used for thermal analysis and structural evaluation including stress, deflection, and distortion. Simultaneously, MathCad is used to perform preliminary vibration analysis and analyze a subsequent FEA model.
The engineering team then uses FEA to perform fatigue analysis on each part using the solid model generated by SolidWorks. Fatigue analysis determines the usable life of each part. The information derived can then be used to predict the need for periodic maintenance or replacement.
Several other tools within the Ansys product family assist in the design process. One tool for electromagnetic simulation is EMag. Using this module allows the engineer to virtually simulate the electromagnetic and electromechanical forces in the solenoid design by evaluating pull-in and response time characteristics related to material selection and part geometry. Response time is how fast the valve moves from one state to another. The module also evaluates magnetic flux related to bobbin and coil design. Valcor’s comprehensive database of analytics provides engineers with a high level of confidence that the new coil designs meet performance specifications prior to prototyping.
Computational fluid dynamics (CFD) software models flow characteristics of the new design. Ansys Fluent and CFX modules integrate the individual parts into a virtual working model of the new valve, allowing engineers to evaluate its theoretical performance against the customer’s specifications. Tweaking subcomponent tolerances and dimensions and evaluating performance changes yields a design that moves to the prototype stage.
Modeling of velocity streamlines through a manifold.
Evaluation and modification
Valcor uses MATLAB/Simulink to further enhance the digital twin’s evaluation. These tools enable the engineering team to model response time, forces acting on critical components of the valve, pressures, flow rates, and determine the acceleration of a particular valve component. Simulink collects the data to analyze the design, and MATLAB controls the virtual model’s performance based on data inputs.
Once engineers are satisfied with the digital twin’s performance, they release the drawings for fabricating the parts needed to build prototypes. The prototype’s performance is tested and compared to the theoretical performance of the digital twin. Here, test results are plotted against the theoretical performance of the valve. By making changes to the critical part dimensions and profiles in CAD and running the simulation model again, the design moves closer to meeting spec. With relatively few iterations of the physical hardware, a design that meets specifications can be arrived at quickly, cost effectively, and moved into production with minimal effort.
As part of the value engineering process, Valcor also uses the digital twin to optimize manufacturability of the valve. Design changes can make the valve easier to assemble without affecting performance, minimizing the need for special fixtures and tools to efficiently build the production valve. Once the valve design performs to the customer’s specification, final drawings are released.
Valcor’s manufacturing team can generate computer aided manufacturing (CAM) programming for each part used in the valve assembly. Computer numerical control (CNC) programmers will review the programming, and occasionally modify it to suit the specific needs of the CNC machining centers. However, using the MATLAB-generated programming eliminates the task of developing from scratch the CNC programming for each part from scratch. The result is the manufacture of quality parts that meet print and are ready for assembly in the final product.
Once in production, Valcor relies on test data to create a feedback loop to the digital twin, which allows them to study the valve’s performance in its intended use, affirm the design’s suitability, and make modifications when application parameters change. The engineers anchor the theoretical model to the test data, helping them refine their tools that can be carried over to future analysis and product design.
The aerospike nozzle provides numerous benefits including reduced fuel consumption and efficiency at a wide range of altitudes. Complex designs can be printed from a single part ceramic.
All photos credit Lithoz
Aerospace is the second largest industry sector served by additive manufacturing (AM), after medicine, according to manufacturing technology advisory firm SmarTech. Yet there remains a lack of awareness about the potential of AM with ceramic materials to make aerospace components rapidly, with increased flexibility and cost effectiveness. AM offers faster and more sustainable production of stronger and lighter ceramic parts – reducing labor costs, minimizing manual assembly, and reducing the weight of aircraft via modelling-developed designs that improve efficiency and performance. Plus, AM ceramic technology offers dimension control in finished parts for features smaller than 100µm.
However, the word ceramic may conjure an incorrect idea of brittleness. In reality, AM ceramics create lighter, highly detailed components boasting huge structural strength, toughness, and resistance to vast temperature ranges. Forward-looking firms are turning to ceramics for components including nozzles and thrusters, electrical insulators, and turbine blades.
Materials
High-purity aluminum oxides, for example, offer high levels of hardness, allied to strong resistance to corrosion and temperature ranges. Components made from alumina are also electrically insulating at high temperatures often found in aerospace systems.
Zirconia-based ceramics satisfy many applications with extreme material demands coupled with high mechanical stress – such as high-end metal forming, valves, and bearings. Silicon nitride ceramics exhibit high strength, high toughness, and excellent thermal shock resistance, along with good chemical resistance to corrosion by many acids, alkalis, and molten metals. Silicon nitride is used in insulators, impellers, and high-temperature low-dielectric antennas.
Composite ceramics provide several desirable qualities. Silica-based ceramics with added alumina and zircon have proved outstanding for manufacturing single crystal casting of turbine blades. This is because ceramic cores made from this material have very low thermal expansion up to 1,500°C, high porosity, exceptional surface quality, and good leachability. Printing these cores enables production of turbine designs that can withstand higher operating temperatures and improve engine efficiency.
Various geometries and materials of ceramics for aerospace applications, including silica-based ceramic cores for investment casting of superalloy turbine blades, zirconia centrifugal impeller, and de Laval combustion nozzles made in silicon nitride.
Benefits of AM ceramics
Injection molding or machining of ceramics is notoriously difficult, and machining provides limited access into a component being manufactured. Features such as thin walls are also difficult to machine.
Lithography-based Ceramic Manufacturing (LCM) used at Lithoz, however, enables manufacturing of precise, complex-shaped 3D ceramic components.
Starting with a CAD model, detailed specs are digitally transferred to the 3D printer. Precisely formulated ceramic-laced powder is then coated on top of a transparent vat. The movable building platform is dipped into the slurry, then selectively exposed to visible light from below. The layer image is generated via a digital micromirror device (DMD) coupled with a projection system. By repeating this process, a three-dimensional green part can be generated layer-by-layer. Following thermal post-processing, the binder is removed and the green parts are sintered – coalesced by a special heating process – resulting in fully dense ceramic components boasting outstanding mechanical properties and surface quality.
LCM technology provides an innovative, cost-efficient, and quicker process for investment casting of turbine engine components – bypassing costly and laborious fabrication of molds required in injection molding and lost-wax casting.
LCM can also realize designs that can’t be made any other way, while also using far less raw material than other methods.
Lithoz ceramic 3D printers allow manufacturing of ceramics with high accuracy and reproducibility from research to production levels.
Bridging the gap
Despite the huge potential of ceramic materials and LCM technology, a gap exists between AM original equipment manufacturers (OEMs) and aerospace designers.
One reason may be resistance to new manufacturing methods within a sector with particularly stringent safety and quality demands. Aerospace manufacturing requires many validation and qualification processes, with thorough, rigorous testing.
Another hurdle includes the perception that 3D printing is primarily suited only for one-off rapid prototyping rather than anything that can go into service in the air. Again, this is a misperception, with 3D-printed ceramic components already proven reliable for serial production.
One example is the manufacture of turbine blades, where AM ceramic processes produce cores for single crystals (SX), along with directionally solidified (DS) and equiax-cast (EX) super-alloy turbine blades. Cores with complex branching structures, multiple walls, and trailing edges smaller than 200µm can be produced quickly and economically, with the final components having consistent dimensional accuracy and excellent surface finish.
Greater communication can bring together aerospace designers and AM OEMs, with full trust in ceramic components made using technology such as LCM. The technology and expertise exist. It requires changing mindsets from AM for R&D and prototyping, to seeing it instead as a way forward for large-scale commercial applications.
As well as education, aerospace firms can invest time in people, engineering, and testing. Manufacturers must become familiar with differing standards and methods for evaluating ceramics, as opposed to metals. Two key ASTM standards used by Lithoz for structural ceramics, for example, are ASTM C1161 for strength testing, and ASTM C1421 for toughness. These standards are used for ceramics produced by all methods. In ceramic AM, the printing step is only a forming method, and the parts go through the same type of sintering as in conventional ceramics. Therefore, the microstructure of the ceramic parts will be very similar to conventional processing.
Where will we be in 10 years?
Based on ongoing advances in materials and technology, we can say with some confidence there will be much more data available for designers. New ceramic materials will be developed and tailored to specific engineering demands. Parts made with AM ceramics will have completed the qualification process for use in aerospace. And better design tools will be available, such as improved modeling software.
By collaborating with LCM technology experts, aerospace firms can bring AM ceramic processes in-house – shortening timelines, reducing costs, and opening opportunities to develop their company’s own intellectual property. With vision and long-term planning, aerospace firms investing in ceramic technology can reap major benefits across their production portfolio through the next decade and beyond.
By forming collaborative partnerships with AM ceramics companies, aerospace OEMs will produce components not previously imagined.
