Keynote Presentation
Megatrends in Near Net Shape Manufacturing
Dr. Diran Apelian - Distinguished Professor, MSE, Director, ACRC @ UCI
Diran Apelian is Distinguished Professor of MSE at the University of California, Irvine, where he is Director of the Advanced Casting Research Center (ACRC) and Associate Director of IDMI – Metal Processing. He is Provost Emeritus and Founding Director of the Metal Processing Institute at WPI, Worcester, Mass.
He received his B.S. degree in metallurgical engineering from Drexel University in 1968 and his doctorate in materials science and engineering from MIT in 1972. Apelian is a Fellow of TMS, ASM, and APMI; he is a member of the National Academy of Engineering (NAE), National Academy of Inventors (NAI), the European Academy of Sciences, the Armenian Academy of Sciences, and the Chinese Academy of Sciences. Apelian is the co-founder of Ascend Elements Inc., Solvus Global LLC, , and Melt Cognition LLC.
It is quite clear that in the 21st century we will need to reinvigorate our efforts to lightweight our infrastructure, reduce carbon footprint during manufacturing, reduce production waste, and recover post-consumer waste and upcycle. Manufacturing is at an inflection point with the advent of data science, digital manufacturing, Industry 4.0, and the changes we are experiencing in the future of work and the worker. In this presentation, the changes we anticipate in near net shape manufacturing will be reviewed and highlighted covering key industries: transportation, housing and architecture, energy production, batteries, fuel cells, electronics, and medical devices. The role of Policy is pivotal as it influences the megatrends that are envisioned. This presentation highlights the policies that need to be shaped by the voice of engineers and technologists to ensure a competitive and a sustainable future.
Gate Size in Metal Injection Molds
Griffin Seidler, Ruger Precision Metals
In plastic injection molding, there are few more important dimensions for the quality of molded part than the gate size. A larger gate allows more material to fill the part during the packing phase of injection, compensating for volumetric shrinkage. Evidence shows that larger gate sizes in Metal Injection Molds benefit metal parts in a similar way. In certain Metal Injection Molding applications, it is sometimes desired to have little to no evidence of the gate on a finished part. Sometimes, this can lead part and mold designers into the trap of building the mold with undersized gates. On parts with relatively large wall thicknesses, this can cause issues including sinks, voids, flow lines, and sometimes cracks. These problems can be discovered before any steel is cut for a mold using a simulation software like AutoDesk Moldflow. This presentation will show how gate size affects different aspects of MIM part quality and how simulation can accurately predict potential issues related to gate size.
Atomization and Characterization of Ferromagnetic Powders for MIM
John Johnson, FAPMI, Novamet/Ultra Fine Specialty Products
Ferromagnetic materials are used in almost all modern electronic equipment. They are also used for magnetic shielding. Metal injection molding enables fabrication of complex magnetic components for advanced applications while also avoiding particle deformation that reduces magnetic properties. Many different ferromagnetic powders can be produced by gas atomization. Some common alloys include Sendust (Fe-Si-Al), molybdenum permalloy (Ni-Fe-Mo), and permendur (Fe-Co-V). The effects of different particle size distributions and post-atomization treatments of these ferromagnetic powders on their magnetic properties, including permeability, coercivity, and saturation induction, are investigated.
Lithography-Based Metal Manufacturing (LMM)
György Attila Harakaly, Incus GmbH
Lithography-based Metal Manufacturing (LMM) is an additive manufacturing technology applying the principle of photopolymerization to metal parts fabrication. For the process, metal powder is dispersed in a light-sensitive binder, and the three-dimensional structure developed layer-by-layer with exposure of light. This so-called feedstock system is solid at room temperature and resolidified between the deposition of the new layers, thus supporting the polymerized parts. This technique allows to apply the benefits of lithography, such as superior surface aesthetics, highly accurate details, and feature resolutions to produce functional metal components, without the typical technological drawback of the necessary print supports.
The printed parts, likewise to other sinter-based metal manufacturing technologies, require a debinding and sintering process step to gain the final metallic properties. LMM is developed to be a complementary technology for Metal Injection Molding (MIM) to support a fast design iteration process and to enable small to mid-scale production for complex geometries up to 200g component mass. The sintered 316L parts achieve >550 MPa tensile strength and >200 MPa yield strength, equivalent to metal parts made with MIM. Additionally, the arithmetic average (Ra) surface roughness values for as-sintered components are <5 µm. The LMM approach enables the production of complex geometries without the risk of material loss during the fabrication process, thus offering an economically and environmentally feasible metal manufacturing method.
Hot Disk Thermal Characterization of MIM Parts at Every Production Stage
Artem Trofimov, Orton Ceramic Foundation
Thermal characterization of metal (MIM) and ceramic (CIM) injection molded parts as well as additively manufactured (AM) materials is vital for modeling and simulations, optimization of the processing parameters, and can be used for quality evaluation of components at different steps of manufacturing. Meanwhile, the evaluation of thermal properties at every production stage (and not only at the final sintering) is challenging due to a necessity to accommodate the testing of both powders and solid samples, as well as insulative and conductive materials (e.g., green and sintered parts, respectively). In this work, Hot Disk Transient Plane Source (TPS) technique is demonstrated as a suitable and convenient tool for the evaluation of thermal properties at all MIM stages, including raw powders, feedstock, green, brown, and sintered parts. The accuracy of the technique will be demonstrated on the example of sintered 17-4PH Charpy bars in comparison to the bulk properties of this material. The ability to test and differentiate between the powders with different particle sizes will be shown on examples of tungsten and 17-4PH alloy. The potential use of Hot Disk as a quality control technique will be illustrated by evaluating and comparing green parts, brown parts, and several partially debind parts with different amounts of residual binder.
Review of Some Sinter-Based Metal Additive Manufacturing Technologies
Animesh Bose, FAPMI, Desktop Metal
The rapid growth of the additive manufacturing (AM) sector has led to the development of a multitude of novel 3D printing processes. Attempts have been made by ASTM/ISO to classify these processes into broad categories. Sinter-based metal additive manufacturing (AM) processes that separate the geometric shaping process and the consolidation step exhibit several advantages over conventional melt-based AM technologies such as laser or ebeam based processes where the consolidation and geometrical shaping are carried out in one step. All the sinter-based AM processes have similarities with powder injection molding (PIM) where the geometrical shaping is separate from the final consolidation (typically by sintering) of the part resulting in isotropic microstructures. This presentation will highlight some of the developments in the traditional sinter-based AM processes and also discuss some of the novel, non-traditional sinter-based AM processes.
Pre-Sinter Rework of Green Parts to Eliminate Molding Defects of MIM Parts
Caleb Spencer, ARC Group Worldwide
In the Metal Injection Molding Industry, during the molding process there are a multitude of defects that occur. Through the sintering process these defects can then turn into cracks, voids, and sinks. This study seeks to determine if a process in the green state can “heal” some of the defects from molding so that when the part goes through final sintering the cracks, voids, and sinks no longer present themselves. This can help the amount of scrap in parts that use high-cost alloys or to fix defects during the sintering stage by adding a processing step pre-sinter so that the previous defects are no longer present in the sintered MIM components.
Extrusion-Based Additive Manufacturing (EAM) of Nickel-Titanium Shape Memory Alloy via Bio-Based Polymer
Hong Wang, Université de Franche-Comté, FEMTO-ST institute
The extrusion-based additive manufacturing (EAM), an adaptation of metal injection molding (MIM), has been used for manufacturing Nickel-Titanium shape memory alloy due to its high cost effectiveness and practicality. In this presentation, the preparation of the feedstock consisting of NiTi powder and a polylactic acid (PLA) based binder, the optimization of the printing parameters, the thermal debinding and sintering processes will be introduced. The rheological behavior of the feedstock is characterized, modelled by constitutive models, and used as input parameters for the finite element simulation relating to extrusion process, which gives an insight of the physical fields of the melt flow inside the nozzle and helps to optimize the processing parameters.
The Relationship Between Molding Variables, Green Part Quality Indicators, and Final Sintered Shrinkage Part Quality
Gustavo Mosquera, SIGMA Plastic Services, Inc
In this presentation we will explore the injection molding process for MIM parts and the quality characteristics of green parts. We will assess each one of the indicators that may be used to evaluate and predict the part final dimensions or aesthetics defects. This will help us understand the effect of different molding variables on the part after sintering, as well as the potential root cause for common molding issues. Finally, we will define the changes needed for any given part defect given certain quality conditions after the molding process.
Simulating Sintering Shrinkage and Distortion for Production Success
Andrew Roberts, Desktop Metal
Sintering is a key step in the manufacturing workflows for both MIM and metal binder jet 3D printing. However, during sintering, many parts experience warpage in the furnace, which may lead to unsatisfactory final results. A new type of software is able to simulate the effects of gravity, friction, shrinkage, and powder density variations that lead to distortion during sintering, and modify the part geometry in order to compensate for this distortion.
We’ll explore the development of a novel Live Sinter technique that enables a full complement of predictive simulation and geometry compensation for sintering distortion combined with a composite scan adjustment to further hone high accuracy sintered results. Predictive simulation includes shrinkage and distortion due to frictional drag, gravity, creep strain, and powder density variations occurring during printing and sintering. The results yield negatively offset parts 3D printed to sinter to near net shaped components within tight tolerances.
A GPU-based multi-physics approach accurately simulates shrinkage and distortion and generates compensated geometry. This allows compensated part geometries to be sintered with minimal to no printed support structures. The software also enables the design of complex ceramic setters that can help guide parts into desired shapes. The technology combines an elastically/plastically deformable dynamic particle model, rigid body collisions, and meshless finite element analysis (FEA), and then tunes the process to match scans of a sintered calibration test part. Once tuned to furnace, printer, and material properties, the technology may be used to simulate and negatively distort parts and supports for subsequent designs, thereby avoiding “trial and error” guesswork.
Review of the MIM Industry in Europe
Paul A Davies, Sandvik Additive Manufacturing
A presentation focusing on a review of the MIM industry in Europe, from a metal powder supplier’s point of view. Featuring a review of recent technical developments, industry news, highlighting companies investments & expansion, as well as MIM research & development in Europe. The European MIM Market has emerged from the global pandemic with great resilience. And while challenges remain, including fluctuating demands for vehicles, consumer reluctance to invest during times of economic stress, shortage of electronic chips and the accelerating switch to electric vehicles, as fuel cost increase and legislation restrictions are implemented. The MIM industry in Europe can take advantage of new trends, such as re-shoring and increased supply chain security, as well as application developments in a number of different industries, including high-added value markets such as medical & aerospace. This presentation will review the state of the industry, drawing on the latest surveys and reports, to compare and contrast the data with the other regions, notably Asia & North America.
Influence on MIM Properties of Different Particle Size Distribution of Special Water Atomized Fine Powder
David Shore, Höganäs AB
17-4PH is the most used alloy in the metal injection molding (MIM) industry due to its high strength and hardness combined with modest corrosion resistance. Particle size distribution (PSD) of the powder used in a feedstock is key in how the end product will perform mechanically, feedstock processability and the appearance of the final components produced. Therefore, choosing a relevant powder fraction for a certain application becomes vital.
This work focused on a special water atomized powder lot of the alloy 17-4PH sieved in different size fractions. A catalytic feedstock with identical powder loading were used for all grades. Properties evaluated were Sintered Density (SD), Melt Flow Index (MFI), mechanical properties and surface roughness.
Impact of Gas Guiding and Advanced User-Friendly Binder Handling Solutions for MIM and AM Furnace Product Line: CFD Simulation, Customer Feedback and Binder Handling Solutions
Maximilian Mungenast, Carbolite Gero GmbH & Co. KG
Precision parts produced using the well-known MIM process need to achieve high demands on their geometry nowadays and suffer from a high price pressure. In series production, differences in carbon content and distortion occur depending on the position of the component in the sintering furnace, especially during production start-up, as the binder is removed inhomogeneously in the usable volume. This results in high costs and loss of time due to empirical loops to improve the process.
In the past CFD simulations were used to analyse the debinding of the MIM process in a Carbolite Gero furnace. The geometry of the furnace, the gas inlet and outlet geometry, as well as the geometry of the entire sample loading and the shape of each individual part have been considered. The aim was to achieve a uniform gas distribution within the useful volume that is as independent as possible of the specific furnace loading. As a review, simulation results are presented in summary, leading to a new generation of MIM sintering furnaces. Experimental results and customer feedback will be presented additionally.
Optimizing the debinding is not enough, since during sintering the gas flow must be changed. As during the debinding step the gas flow must be optimized in order to remove the binder, in the sintering phase uniformity is the important parameter.
Therefore in the second step, the sintering process was analyzed using another CFD simulation. The aim was to determine the influence of the necessary gas flows during sintering in the MIM furnace. In the simulation, the optimal quantities of gas flows, the total gas flow and the distribution from front to back in the furnace were analysed. All these theoretical analyses were performed in order to achieve uniformity and minimum distortion of the components. The simulation results of the sintering optimisation will be presented.
CASE STUDY: Utilizing Metal Injection Molding and AM Binder Jetting in the Production of a 316L Industrial Part
Gaetano Mariella, Polymer Technologies Inc.
Metal additive manufacturing (Metal AM), specifically the sintering based, binder jet technology can provide complex shape creation with no tooling. This fact enables the creation of numerous design variations quickly and supplies part samples for process iterations. Binder Jetting production capability is somewhat limited to low and medium rate production. Metal Injection Molding (MIM), also sintering based, is used to produce near net or net complex shapes in advanced metals or alloys. Currently, (MIM) provides an advantage over Metal AM for medium to high volume production.
This presentation provides a case study for the production of a 316L SS industrial part brought thru initial design, DFM for manufacturing, final product design stage and production using both Metal AM - binder jetting technology and Metal Injection Molding (MIM).
Binder jetting was used to streamline and narrow initial design feasibility- DFM, clarify dimensional tolerances achievable after debinding and sintering and develop CNC programs and machining fixturing in the LRIP stage. Later MIM processing used the information gained from the binder jetting LRIP parts, to determine part feature sizes, sintering orientations and machining fixturing.
The marriage of Metal AM- binder jetting and metal injection molding (MIM) prove to be powerful allies in bringing down new part design cycle time, process development and overall time to full rate production.
Effect of Feedstock, Filament, and Green Part Characteristics on Sintered Properties of Material Extrusion (MEX) 3D Printed Copper
Kameswara Pavan Kumar Ajjarapu, University of Louisville
To adapt metal injection molding (MIM) principles to material extrusion (MEX) 3D printing, it is crucial to understand how materials behave during the 3D printing process due to variation in powder-polymer concentration that affects green part quality, dimensional accuracy, and minimize processing defects. Therefore, it is essential to understand and identify how the feedstock, filament, and green part characteristics affect the final sintered density of parts fabricated via MEX 3D printing. In the current work, copper powder-filled polymeric feedstocks and filaments with 58 vol.% solids loading were prepared and characterized for physical, thermal, and rheological properties. Subsequently, the filaments were extruded at three temperatures near the glass transition temperature of the feedstock to understand if filaments can be fabricated with varying degrees of packing densities. The extruded filaments were 3D printed into tensile and tablet geometries via a benchtop MEX-AM machine. The green parts were sintered and characterized to understand how the sintered physical and mechanical properties scale compared to the variation in filament packing characteristics. Density measurements and SEM images were collected at each step to keep track of porosity and powder packing density from green to sintered state. This work aims to identify and develop a process flow that can help qualify a given material system and outline the importance of filament packing characteristics for 3D printing via MEX technology while comparing the results with parts fabricated via MIM.
Binder System for Powder Injection Molding of NdFeB Permanent Magnets
Vahid Momeni, Institute of Polymer Processing of the Montanuniversitaet Leoben
Metal injection molding (MIM) is a proven technology for producing low-cost, complex-geometry components. In this process, the feedstock formulation is one of the most influential factors for the final properties, especially for oxygen-sensitive materials like NdFeB. In this study, feedstocks with binder systems composed of low-density polyethylene (LDPE), paraffin wax (PW), stearic acid (SA), and different powder loading were produced. Measuring the oxygen and carbon contamination in the NdFeB components after debinding and sintering revealed that an increase in O and C can reduce the density. Based on the findings, the optimal binder formulation consisted of 47.5% PW, 45.5% LDPE, and 7.5% SA with the lowest amount of C and O contamination.
Performance of Highly Uniform High Density Multimodal Stainless Steel Powders in Metal Injection Molding
Joseph Schramm, Uniformity Labs
The achievable tolerances of parts made by metal injection molding are determined by sintering shrinkage and uniformity of sintering shrinkage, which are, in turn determined largely by powder loading and uniformity of powder loading in the molded green part. The current state of the art somewhat limits the maximum size of metal injection molded parts. Here multimodal mixtures of spherical stainless steel powders having high tapped density and high spatial uniformity have been used to produce highly loaded feedstock and molded into parts showing sintering shrinkage of around 12%. In addition, these high-density powders retain manageable flowability when compounded into MIM feedstock, and can provide 1000x more contact points hereby facilitating the sintering process. The high uniformity and low sintering shrinkage of molded parts results in tight tolerances and minimal warpage opening metal injection molding to a broader range of potential applications with notable commercial benefits, such as the production of larger parts or more precise smaller parts. Furthermore, the powders discussed here utilize a larger portion of an atomization curve resulting in less material waste and a more sustainable process.
Tungsten Carbide PM Products in High Precision and High-performance Engineered Tooling and Wear Solutions
Jeffrey Taylor, Crafts Technology, A Hyperion Materials & Technology Company
Tungsten carbide powdered metallurgy has played a critical role in the development of high precision injection mold tooling over the past decade, having essentially become the Best Available Technology (BAT) as it relates to the design and utility of tooling components such as core pins, valve gate bushings, nozzles, and inserts.
Some of the highest precision and highest volume plastic automotive components, medical consumables, and consumer goods in the world are now being produced at speeds and quality levels previously unattainable with commonly used hardened steels, aluminum and beryllium copper alloys.
Tungsten carbide powder metallurgy has afforded tool designers and fabricators the ability to design tooling that can significantly improve tool rigidity and wear life while also improving thermal conductivity and reducing the coefficient of friction. These are attractive features in a tool design as mold builders and molders alike regularly endeavor to improve part quality and reduce cycle time, while also being able to more easily eject parts from the mold and reduce mold maintenance intervals. Molders and mold builders no longer have to sacrifice or trade off these benefits when they elect to utilize tungsten carbide in their tooling designs.
Development of Flexible Magnetic Micropillar Actuator via Powder Injection Molding
Jin Wook Park, Korea Institute of Materials Science - Pusan National University
The development of micro/nano-parts with magnetic soft composites such as actuators and the soft robot is currently promising. Accordingly, the development of parts using magnetic soft composites has been conducted. However, those applications were manufactured by PDMS (polydimethylsiloxane) casting which is inefficient in manufacturing. Thus, the manufacturing process needs to be developed for mass production. Here, we developed the manufacturing process of a flexible magnetic micropillar actuator with an injection molding process. To shape the micropillar, polymethyl methacrylate (PMMA) insert molds were prepared by X-ray lithography. Magnetic soft composite, which was blended with magnetic powder and elastomer, was injected by applying the magnetic field in the mold cavity during the injection molding. Our manufacturing method opens the way to fabricate a flexible magnetic micropillar actuator as a mass production approach having high dimensional freedom.
Beyond Binder Jetting – Alternate Sinter Based AM Technologies
Benjamin Arnold, Tritone Technologies
As Binder Jet sinter based metal AM technology gains traction and headlines, other new processes for green part manufacturing technologies are emerging. This talk will highlight how these technologies address several key challenges facing binder jet.
We will share the technical basis of one such technology and share use cases and test data highlighting how improvements in mechanical properties, dimensional consistency and green part strength are opening new application opportunities.
Printable Filament Design of 316L Stainless Steel Master Alloys
Marina Valero Rodrigo, Universidad de Castilla – La Mancha
The purpose of this study is design filaments for Fused Filament Fabrication (FFF) technology using carbonyl and master alloy powders of 316L stainless steel, where the final alloying is achieved during the sintering stage. The advantage of using master alloy (that doesn’t exist in the market filaments) is better shape retention than conventional pre-alloyed powders. Based on feedstock rheology (using a capillary and oscillatory rheometer) and mechanical properties, the binder system and the optimum powder loading can be determined. After that, feedstocks can be printed as filaments employing the results of limiting force of the previously studied properties. Once finished the sintering stage, density and hardness achieved are comparable to 316L SS parts processed by other techniques.
The Missing Link of MIM
Lucas Logan, ARC Group Worldwide
MIM parts often have dimensional non-confomances due to process variation, wherin parts made within the same molding run will be measurably different from each other despite using the same tool, press, debind run, sinter run, and feedstock lot. This variation is currently one of the fundamental limitations to the accuracy with which MIM'ed parts can be produced. We have found evidence that there is a substantial difference in the density, and thus effective powder loading, of feedstock granules that seems to be related to the granule size. By intentionally limiting the granule size range of the feedstock used for a particular molding run we hope to improve the consistency of parts produced during that run.
How Ti BJP Compliments Ti MIM
Victor Villarini, TriTech Titanium Parts
In this presentation, the speaker will describe how Titanium Binder Jet Printing processing can help and support Titanium Metal Injection Molding business. The processes will be compared in terms of prototyping, time to market, sintering, and properties. Our goal is to explain how we can use BJP to help develop MIM customers as well as look at ways binder jet printing does not help.
Additive Manufacturing of Aluminum Alloy by Metal Fused Filament Fabrication (MF3)
Sihan Zhang, University of Louisville
This research studies additive manufacturing of aluminum alloy via metal-fused filament fabrication (MF3). Feedstock was prepared by mixing Al-6061 powder and polymer binder and then extruded via capillary rheometry to form a filament. The filament was used to print green parts with common FDM 3D printers. The green parts would go through solvent debinding, thermal debinding and finally sintering processes to remove polymer content and become dense metal parts. Resulting grain structure, sintered density, and mechanical properties will be characterized and compared to metal injection molded (MIM) specimens. The main objective is to apply MF3 process on aluminum alloys and optimize the process parameters for better mechanical properties. The overarching goal is to enable rapid, predictable, reproducible, low cost, and accurate production of metal parts with 3D features, thereby significantly expanding the current additive manufacturing capability.
Metal Additive Manufacturing by Continuous De-Bind and Sintering of Binder Jetted Products
Stephen Feldbauer, Abbott Furnace Co.
Metal Injection Molding was the first technology to allow rapid production of complex shapes. This familiarity with complexity has made Metal Additive Manufacturing an excellent fit with many MIM shops. Binder Jetting has moved to the forfront of additive manufacturing because of its ability to print materials that cannot be joined through a melt based process, such as Laser Bed Fusion. It has also been recognized as one of the most promising methods of metal additive manufacturing to be able to produce at a volume that will anable to additive technology to move from a boutique specialty process to a viable process for large scale manufacturing. In the past, the sintering step of the binder jetting process has been done in a vacuum furnace. It was thought that this would allow the producer to move into the market in a more competitive position of cost and flexibility; however, recent developments in continuous sintering furnaces have proven this to no longer be true. Lower capital costs, maintenance cost, operating costs, and better quality are now available from a continuous system that also offers the manufacturer to move to high volume production. Here we will compare these technologies and discuss the nuances of each.
Additively Manufactured Metal Heat Exchangers for Energy Applications
Julio Jair Izquierdo, University of Louisville
Heat exchangers are currently manufactured with a variety of techniques that are reliable and had driven the cost to a very affordable price. However, advancements in additive manufacturing (AM) now enable high-performance non-conventional designs that are not manufacturable with traditional methods. We focus on the design, fabrication and performance characterization of triply periodic minimal surface (TPMS) copper heat sinks and falling-particle inconel-625 high-temperature heat exchangers for different energy applications. The heat sinks are fabricated using metal fused filament fabrication (MF3) with copper-saturated feedstocks that result in a 99% metal density after sintering, while the inconel-625 heat exchangers are fabricated using laser powder bed with a variety of powder sizes. This work serves as an example of how advances in manufacturing technology can lead to innovative solutions for the energy sector.