Additive Manufacturing of Complex 17-4 PH Parts to MIM Standards via FFF

Michelle Chao, Markforged
The idea of bringing MIM to the average engineer has spurred several companies to introduce fused filament fabrication (FFF) methods to produce metal parts. As shown in this talk, similar to 3D printing of polymeric materials, FFF can readily produce a wide range of geometries, including sealed internal cavities and complex features with automatically generated supports. These printed parts can be debound, sintered and post-processed similarly to MIM parts, and with properties that meet or exceed MIM standards (e.g. >96% density, 1050 MPa ultimate strength). This talk will highlight the capabilities of FFF metal additive manufacturing through examples of 17-4 PH parts made for prototyping applications and explore the method’s use for pilot scale production.

Additively Manufactured Non-Weldable Super Alloys

Mats Persson, Digital Metal AB
Super alloys is a material group that have significant attention within additive manufacturing. Customization and weight optimizations as well as flexible manufacturing of components will contribute to more energy efficient solutions in sectors such as Aerospace and Power generation.
Some technically important Super alloys are non-weldable grades, making them difficult to produce without cracking with selective melting technologies where high solidification rates and thermal gradients are inherent. Metal Binder Jetting being an ambient temperature printing processes followed by a sintering where densification takes place without melting and with minimal thermal gradients does not experience these difficulties.
Digital Metal® binder jetting technology offers the capacity to rapidly and cost-effectively produce highly complex and intricate designs and features for metallic parts with high resolution and good surface finish. The two step process including ambient temperature printing followed by densification by sintering offer unique ability to process a wide range of metallic materials.
Inconel 625 and MAR M-247 have been successfully manufactured by the technology. Resulting density, chemical composition and microstructures are reported along with mechanical properties at room temperature.

BASF Ultrafuse 316LX—Easy, Affordable Metal Additive Manufacturing

Ben Rader, BASF Corporation
BASF’s Catamold® feedstock has been adapted for metal Additive Manufacturing (AM), via Fused Filament Fabrication (FFF), with the development of its Ultrafuse 316LX filament. This technology offers existing Catamold® MIM customers a low-investment entry into metal Additive Manufacturing, for prototyping or development of new applications. Ultrafuse 316LX can be used with almost any FFF AM system. Once a part is built, no additional post-processing steps are required prior to debinding and sintering. Taking advantage of the reliability and high productivity of catalytic debinding, Ultrafuse 316LX enables simple production of fully-sintered 316L stainless steel components. This is an ideal option for companies already using catalytic debinding and sintering in their manufacturing operations, that can now easily step into and explore metal AM. Ultrafuse 316LX parts can also debind and sinter alongside their traditional MIM components, eliminating the cost and time involved in special/additional furnace runs. BASF 3D Printing Solutions GmbH highlights the significant potential of this technology as a cost-effective entry point into metal AM.

Case Study of Mechanical Properties and Dimensional Variation Related to Residence Time of 4605 and 17-4 PH MIM Feedstocks

Kimberly Cullian, ARC Group Worldwide
The rapid growth of metal injection molding (MIM) in the 21st Century continues to push the development and the capabilities of the technology. With the increased demand for cost effective, reliable products from many MIM vendors, a key focus has been on improvements in the processing of MIM materials and the stability around each process. A study on the dimensional and mechanical aspects of MIM parts in relation to the residence time during molding will further push the understanding of material characteristics in the very early stages of the process. The study will focus on 17-4PH and 4605 feedstocks across multiple injection unit sizes. The case study is intended to understand what dimensional variations and changes in the mechanical properties are associated with the residence time during molding. Testing is intended to be completed in the sintered state, all processes post molding will remain constant.

Characterization of IN713C MIM Parts Made from Nitrogen Atomized Metal Powder

Martin Kearns, Sandvik
MIM is increasing in popularity for manufacture of parts in high performance nickel base superalloys. A number of components are now qualified for hot service environments in aero and powergen applications where excellent hot strength, oxidation resistance and low cycle fatigue resistance are required. MIM is increasingly seen as a viable, cost-effective alternative to investment casting when making small, complex parts from hard-to-machine and expensive alloys in high volume. Various studies have been published on Inconel alloys including gamma prime-strengthened alloys IN718 and IN713C. For these and other alloys containing Al, Ti, it has been considered preferable to use powders made by atomizing in argon rather than nitrogen to minimize nitride formation during processing. This inevitably incurs higher cost and has discouraged the wider use of such alloys in high volume applications. It is the purpose of this study to explore the potential for using lower cost nitrogen atomized nickel superalloy powders in high temperature auto applications. We characterize the microstructures of sintered parts and report on room temperature and elevated temperature tensile tests and compare with results obtained from parts made using argon atomized powders.

Comparison of the Effects of Pre-Alloy and Master Alloy Powders on Stainless Steel Metal Injection Molded Parts

J. Alan Sago, MPP
This study will investigate and compare the effects of Metal Injection Molded parts produced from feedstocks composed of pre-alloy versus master alloy blends of stainless steel alloys powders. The study will investigate the effects of the different powder approaches on the resultant feedstock molding behaviors, sintered part microstructures, and part density. In addition, an examination of the economic cost impact of the different powder blends will also be presented. Stainless steel MIM parts of 316L and 17-4PH will be examined.

The Effect of Carbon Content on the Dimensions of MIM 17-4 PH Parts

Mike Stucky, Norwood
The effects of carbon content on the mechanical and physical properties of MIM 17-4PH are well known. As carbon content increases it will tend to drive up tensile strength and hardness at the expense of corrosion resistance. In this study we will show that carbon content can also have a direct effect on the dimensions of a MIM part.

Effect of Sintering Conditions to Magnetic Behaviour of Nickel-free MIM X15CrMnMoN 17-11-3

Shin lee, Chenming Mold Ind. Corp. (UNEEC)
Recent technology trend and requests from communication and electronic industry are getting higher, such as high strength, non-magnetism, high corrosion resistance and good surface quality. High nitrogen and nickel-free X15CrMnMoN 17-11-3 austenite stainless steels, which is one of the promising candidates, was fabricated by metal injection molding (MIM) process via the commercial ready-to-use feedstocks in this study. In this paper, a systematic study on different sintering conditions was discussed to obtain the optimization production condition. Their effects to the microstructure δ-ferrite / austenite phases formation, and elemental composition variation were also discussed to find the root cause of weak ferromagnetism. From XRD analysis, major phase is based on austenite (FCC) phase; however, the ferrite (BCC) phase is observed on the outer surface from cross-section metallographic images. From EPMA analysis, nitrogen and nickel elemental distribution is uniform through outer surface to central region; however this is not the case for Mn distribution which showed relatively lower concentration near outer surface. This will reduce austenite phase stability due to Mn is the austenitic phase stabilizer. Meanwhile, for one specific parameter among all, the relatively higher nitrogen concentration specimens were obtained. Even the insufficient Mn profile in this set, the austenite phase could still be presented due to higher nitrogen could compensate the loss of Mn and in turn stabilize the austenitic phase.

Effects of Heat Treatment on Mechanical Properties of (MIM) Nimonic 90

Boon Sing NG, AMT PTE Ltd
Nimonic 90 is specially designed to service at high temperatures. The main use of this alloy is to fabricate the turbine blade, dics, forging, ring sections and hot working tools. Thus far, there is only one academic publication on the MIM Nimonic 90 found on 2012. AMT has initiated the development of MIM Nimonic 90 to create the need of powder injection molding (PIM) of superalloys for a variety of gas turbine engine parts. This study mainly focuses on the effects of heat treatment on the mechanical properties of MIM Nimonic 90. It was proven that a modified heat treatment profile with a 3rd phase heat treatment increases the ductility without sacrificing much tensile properties. MIM Nimonic 90 demonstrated comparable mechanical properties at room temperature compared to the extruded bar produced by Special Metals. It provided yield strength and ultimate tensile strength at 700MPa and 1000MPa respectively with ductility of 19%. The density of MIM part achieved 99% with porosity level lower than 1% before HIP. To improve the ductility, heat treated MIM Nimonic 90 parts were subjected to additional heat treatment (3rd Phase treatment). After completing this heat treatment, the yield strength and ultimate tensile strength slightly decreased (YS : 622MPa, UTS : 978MPa) while the ductility was improved from 19% to 26%. During creep test (300ºC), MIM Nimonic 90 survived perfectly at 550MPa after 100 hours of cycle time. Microstructural analysis revealed the formation of carbide and γ’ phases in the main matrix. Carbide phase segregation was not continuously along the grain boundary with the shape of nodular particles. It provided the ductility properties to the main matrix as well as inhibited the grain boundary sliding. γ’ phase accumulated at the surrounding of the pores and carbide. This phase was responsible mainly for the creep properties. MIM Nimonic 90 proves to be an alternative to wrought Nimonic 90 in application where it involves complex shapes. It will provide reduction to cost on secondary machining and materials wastage.

Effects of Thermal Processing and Time On Cold Worked MIM Components

Levi Rust, ARC Group Worldwide
There are many factors that come into account when manufacturing a part to meet customer print specifications. In the Metal Injection Molding Industry the need for cold working parts is a necessity for part manufacturers. The theory is that after cold working operations, parts relax as time progresses and or thermal processing is performed. The objective of this study is it to determine the effects of time and thermal processing on critical part dimensions of cold worked parts.

Fatigue Study of 316L Produced Using Binder Jet 3D Printing With Hot Isostatic Pressing

Andrew Klein, ExOne
Binder jet 3D printers utilize MIM powders to print green parts in a layer-by-layer process. After printing, parts are sintered in the same furnaces used by MIM to produce sintered parts ranging from 97-99% dense. With MIM parts, hot isostatic pressing (HIP) can be used to eliminate internal defects like residual porosity in sintered parts. By eliminating internal porosity, the ductility, fracture toughness and fatigue properties of the material can be improved. Given the similarities of the MIM process and binder jet printing, it is expected that using HIP on parts produced using binder jet 3D printers will produce comparable improvements. This presentation will present a study on the fatigue performance of binder jet printed 316L. The fatigue properties have been evaluated for three different variants including as-sintered and then material that is post-processed with two different HIP cycles. Microstructural evaluation will also be done to draw further conclusions about the fatigue results.

Five Reasons to Celebrate Mold Cleaning in MIM

Steve Wilson, Cold Jet LLC
If there’s any segment of injection molding that has to clean molds frequently, its MIM processors. No matter how large or small of a molding operation, custom or captive, MIM processors deal with frequent mold fouling from the binders used in MIM. Keeping Mold cavities clean and vents open is critical for successful molding. How you clean your molds can mean the difference between mediocre performance and good OEE scores translating to high-profit productivity. Traditional methods not only can create extended downtown, but can cause mold wear to parting lines, sealing surfaces and various surface finishes. This presentation discusses the top 5 reasons MIM molders are turning to dry ice solutions to clean their molds while they are still in the machine, at operating temperatures, in a very quick and effective manner, without causing and wear to the tool.
This presentation will also provide the attendee a working knowledge of the theory and process of how dry ice cleaning works and how to adapt it to various other cleaning opportunities in their factories, i.e. screw cleaning. This presentation includes supporting research from several independent studies, along with several industry case studies, pictures and videos.

Future Growth in PIM—Materials, Applications, and Processes

Randall German, FAPMI, San Diego State University
The current status with injection molding and binder jetting provides a foundation for assessing pacing issues on growth. Three separate directions for growth are identified from a technical-market review. New materials are identified based on the early success with carbon-free stainless steels, then heat treatable carbon steels, and now sophisticated reactive, refractory, and high temperature alloys. New applications of merit come from long-wave markets, especially where structural response is dominant. Examples are identified in implants, thermal management, and aerospace situations. Finally, the third growth direction is associated with processing advances, including improved dimensional control, higher process yield, reduced time to market, integrated hot isostatic pressing, and fast sintering cycles. Progress in these three directions is illustrated.

Impact of Gas Guiding in an Improved MIM Sintering Furnace: CFD Simulations and Initial Experimental Results

Timm Ohnweiler, Carbolite Gero
Nowadays precision components fabricated by the well known MIM process have to fulfill high requirements to their geometry and suffer from a high pricing pressure. During serial production differences occur in carbon content and distortion in dependence of the position of the part inside the sintering furnace, especially during start of production, because the binder is carried away inhomogeneously in the usable volume. Hence, high costs are generated, and time is lost due to empirical loops to improve the process.
In order to overcome these problems, simulations are carried out to improve the situation beforehand. By a Computational Fluid Dynamics (CFD) approach, the geometry of the furnace, the gas inlet and outlet geometry as well as the geometry of the whole sample load and the shape of each individual part is taken into account: The aim is to improve the furnace in a first step in such a way to get a uniform gas distribution inside the usable volume, which is as much as possible independent of the specific furnace load. As the furnace load for sure influences the gas paths, the second step is to find the optimum load and sample orientation with as much samples inside the furnace as possible together with the right settings of gas flow. As an outlook this second step shall be developed as a software package in the future, allowing to quickly calculate the optimum load for the furnace whenever parts geometry is varied.
Initial simulation results will be presented, which were leading to a new generation of MIM sintering furnaces (type PDS 120 MO/14-3G MIM). Several next generation PDS are in full operation at customer site since 2018. The main design concepts are discussed. The presented results are part of an enclosed study as well as of an ongoing phd study, both in behalf of Carbolite Gero.

Limitations of Metal Powder Configurations at High Metal Loading in MIM Feedstocks

Lane Donoho, Advanced Metalworking Practices

This study will evaluate the impact that various percentages of carbonyl iron (CIP) and water atomized (WA) powders play on the viscosity and moldability of MIM feedstocks. Specifically, the limitations that high metal loading places on the volume percentages of irregular base metals will be investigated. Feedstocks with varying degrees of CIP and WA will be compounded and characterized using capillary rheometery. Charpy impact bars will be molded and sintered from viable feedstocks. Ultimately, the study will investigate the effects of the different powder approaches on the resultant feedstock molding behaviors and final part sintered density.

Melt-Free Titanium Alloy Powder: Production Facility and Development Center

Art Kracke, AAK Consulting LLC
The advanced industrial revolution awakened the demand for powder metals. Virtually no alloy system is being left behind as businesses, from around the world in diverse industries, participate in the revolution. Perhaps the powder alloy system seeing the greatest growth is titanium. This is not surprising considering the demand for titanium alloy mill products and castings has grown for decades. The growth engines of titanium powder demand are the biomedical and aerospace industries. However, other industries, such as automotive and consumer products, have renewed interest in titanium parts and components made from powder.
Advanced manufacturing, enabled by powder metals, is stepping-up with innovations that lower cost while improving part performance and shortening development and production cycle-times.
This presentation will discuss Coogee Titanium’s 10+ year development innovation which resulted in the construction of a production facility for melt-free Ti 6-4 powder.
Melt-free processing will dramatically lower cost facilitating growth for years to come. Titanium alloy powders, their time has come.

MIM Mechanical Properties Using New High Density 420 Stainless Steel Alloy Powder

Taku Kawasaki, Epson Atmix
For many years, Epson Atmix has studied methods of producing high density MIM sintered components, utilizing our pre-alloyed powders. Our goal has been to develop powders and processes that allow us to negate the need for HIP processing, thus saving time and money. A recent result is reported on with our 420J2 powder, 7 micron D50, having an as sintered density of 99.5% theoretical. Specimens were produced using general MIM processing. A tensile strength of 1,770 MPa, elongation of 6%, and hardness values of 600 Hv were achieved. These values are comparable to as HIP’ed properties of gas atomized powders.

MIM World Status—2019

Matthew Bulger, ATPM Consulting
A past president of MIMA will provide a brief history of MIM,; his perspective overview of the current MIM landscape for Europe, North America, and Asia. He will also discuss feedstock, powders, and future developments.

Optimized Properties in Sintered 17-4 PH Stainless Steel

Randall German, FAPMI, San Diego State University
A popular alloy for additive and injection technologies, 17-4 PH is a subtle alloy with respect to optimized sintered properties; reflecting phase transformation, microstructure, impurity interactions that depend on binder, powder, temperature, atmosphere, and hold time parameters. Densification behavior is reviewed versus each of these factors, including initial powder chemistry and sintering atmosphere. Microstructure evolution is captured by quenching during heating through the critical stages of sintering. Sintering densification is linked via X-ray diffraction analysis to reveal the role of austenite and delta–ferrite versus temperature. Pore elimination is favored by manipulation of the phases, depending on hydrogen as the atmosphere or carbon and nitrogen as impurities. Final tensile properties after heat treatment indicate a need for modified cycles to delivery optimal properties.

Relationship of Shear Rate and Particle Segregation in MIM Parts

Gabriel Geyne, SIGMASOFT Virtual Molding
Particle concentration is an intrinsic property of MIM materials. Variations in part wall thickness and process parameters may result in poor control over it and result in undesired green part density. The final shrinkage of the part after sintered is a result of all this variables. This presentation will address the issues related to particle concentration, green part density and shrinkage.

Understanding Surface Area Measurement Techniques for Improved Powder Production

Jack Saad, Micromeritics Instrument Corporation
A critical attribute that contributes to the quality of a manufacturing process is the surface area of the feedstock raw material. Surface area gives information amount of surface available to interact with binders which can offer a prediction of how the powder will behave. However, due to advances in technology, there are different techniques available and regularly used in industry to determine surface area. In this study, we explore and compare three techniques used to determine surface area of common metal powders. These techniques are BET method by gas adsorption, air permeability method, and calculated method from particle size and density data. In addition, these techniques also provide additional useful information about the metal powders, including porosity, density, and particle size.