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Abstracts


Keynote Presentation - The Question: Is MIM there yet?
Randall M. German, FAPMI, San Diego State University
The foundations for Metal Injection Molding started soon after plastic injection molding. But process control and other details were missing. Success, both technical and financial, required decades, so there was no benefit from being first. Once the mystery on the technology disappeared, MIM expanded rapidly. In this talk some of the historical key points are identified in terms of who, what, why, when, and where. Some of the most significant developments trace to answering a few difficult early questions.


Effect of Grain Size in Granulated MIM Feedstock
Kimberly R. Cullian, ARC Group Worldwide
In the Metal Injection Molding (MIM) industry, feedstock can be manufactured in either pelletized or granulated form. It is theorized that, when utilizing a wax-polymer binder system, variation in the grain size of granulated MIM feedstock could have implications on final part properties. The objective of this study is to better characterize the impact to dimensional and mechanical properties of alternate grain sizes of a granulated MIM feedstock. Three separate grain sizes will be tested and all processes post- molding will be held constant. Evaluation and analysis will be completed post-sinter.


Model for Thermal Debinding of MIM "Green" Parts for Higher Production Rate Operations
Harb S. Nayar, FAPMI, TAT Technologies
Using a typical MIM feedstock used to produce "green" Metal Injection Molded parts weighing up to a couple of hundred grams, a model, process and results will be presented that will allow debinding and sintering in one operation at high temperature in batch or continuous conveyor furnace under H2-based atmosphere at a rate upto and above 100 lbs per hour at lower energy cost. The model will include removal of organic binders as vapors, sweeping the vapors toward front end of the furnace and "destroying" the organic vapors into harmless emissions before the vapors exit the front end of the furnace.


Ideal Sintering Ceramic Setter Designs for MIM Components
Sachin Malgave, Indo-MIM Pvt. Ltd.
Getting high first pass yields in sintering thereby avoiding or minimizing complex coining or sizing operations post-sintering has been a necessity to take the real benefits of MIM technology to our customers. The complex interplay between sintering force of fine MIM powders coupled with gravitational forces and frictional drag force makes design of right ceramic setters an iterative long drawn process. In this study, based on the vast experience of sintering close to 5000 different varieties of MIM parts (large to small), broad guidelines for design of sintering setters for MIM parts of various geometries to minimize the effect of gravity and frictional drag is being presented. While the present mathematical models for sintering mostly deal at particulate level, extrapolating the same models for a real MIM Part has been a challenge. In this study, a practical methodology to measure sintering force which is a key parameter that would help in designing the right staging method of MIM parts is being proposed.


MIM 465 Stainless Steel as an Alternative to 17-4PH
Michael Stucky, Norwood Medical
MIM 17-4PH is a workhorse alloy for the MIM industry in general and is especially important for the medical device industry do to its high strength combined with good corrosion resistance. As the medical industry pushes for more complex devices that can perform multiple functions in the same or smaller space the designs require smaller, thinner parts while still maintaining high strength. This has pushed 17-4PH to the edge, and sometimes beyond, it’s capabilities. In response the designers are looking at other alloys that can get them the properties they need. One such alloy is Carpenter’s patented alloy 465. This paper will investigate the mechanical properties that this alloy can provide through a MIM process.


Comparison of Ti-6AL-4V Fabricated via MIM and Binder Jet Printing
Joseph Grohowski, Praxis Powder Technology Inc.
Binder jet printing offers the exciting possibility of rapidly producing articles comparable to green injection molded parts. Equipment already present in a conventional titanium MIM processing line has the potential to be used to debind and sinter green articles manufactured via binder jet printing. Ti-6L4V samples were fabricated by metal injection molding and binder jet printing. Samples were compared throughout the processing steps. Finished samples were compared on the basis of chemistry, microstructure and mechanical properties.


Microstructure and Magnetic Properties of Magnetic Alloys Fabricated by MIM
Mary Kate Johnston (Peng Yu), Sandvik Osprey Ltd.
Magnetic materials have featured prominently in the MIM industry from its earliest days with the manufacture of a wide range of components based on ferrite and carbonyl iron and advancing to prealloyed ferrous (FeSi, FeCr) and nickel base (FeNi, FeNiMo) materials. In recent years there has been increasing interest in higher performance soft magnetic materials for electronic devices and automotive applications. Here, the goal is to achieve high magnetic flux saturation (Bs) at low coercive force (Hc) by control of the alloy microstructure. In this study, we examine the impact of different powder raw materials and sintering conditions on the microstructure and magnetic properties of FeCo alloys. It is shown that microstructural features affect magnetic permeability and that control of sintering parameters is critical in optimizing magnetic performance.


Effect of Humidity on the Flow Properties of Metal Powders
Martin Laloux, GranuTools
Granular materials and metallic fine powders are widely used in many industries (3D Printing, sintering, alloys, …). To control and optimize the processing methods, the physics of powders must be precisely analysed. Moreover, the collective behaviour of powders such as the flowability (GranuDrum instrument), compaction dynamic (GranuPack device), and the triboelectric effect (GranuCharge instrument) on powders are key parameters in several dynamic processes, such as pneumatic conveying, additive manufacturing (during recoater operation) etc. In this presentation, we will focus on powder bed based additive manufacturing processes and in particular on powder spreadability. The measurement methods are based on the rotating drum principle, powder packing fraction, and electrostatic charge generation. In order to avoid the unwanted end, some powders can be treated with a special coating to decrease its tendency to charge in contact with a specific material (SS 316L in this study), improving spreadability and compaction dynamics. In addition, some coating is also sensitive to humidity/temperature conditions. In this research, we show how a metallic powder reacts in contact with humidity. It will be shown that the humidity modifies the product chemistry, resulting in a charging behaviour decrease, spreadability, and packing dynamics improves. A low Cohesive Index is observed for a powder easy to spread and a fast packing dynamic yield a mechanical piece with a lower porosity.


The Effect of Hot Working MIM Components
Brodie Van Allen, ARC Group Worldwide
Distortion of complex part geometries through the debind and sinter processes is common in the Metal Injection Molding (MIM) industry. As such, secondary processing of MIM components is often necessary to achieve customer specifications. Typically, parts are cold worked post- sinter in order to bring parts into compliance. However, cold working does have certain limitations depending on the material and process. This study will explore the effect hot working has on dimensional characteristics of MIM components at varying elevated temperatures when compared to the standard cold


3D Printing of Metals and Ceramics
Jan Sumerel, BASF
BASF has a successful history producing Catamold feedstocks for metal injection molding (MIM). In this presentation, we will show our work using these feedstocks to produce stainless steel and ceramic filaments for successful additive manufacturing employing filament fused fabrication (FFF) methodologies. We will show the entire process flow from initial part design considerations through the printing, debinding and sintering, and post-processing steps and discuss process requirements. We will show the resulting mechanical properties of these printed parts and compare the results of this process to traditional MIM technologies.


Gas Flow Optimization in the MIM Sintering Furnace Using CFD Simulation
Timm Ohnweiler, Carbolite Ger GmbH
The influence of temperature and holding time on the debinding and sintering process is well known. However, the influence or the adjustment possibilities of the gas flow are often underestimated. By using CFD simulations, it has already been possible to achieve improvements in the gas flow on the PDS 120, which has led to a more stable sintering process over the entire furnace volume. This has now also to be implemented in other furnace models and improved by further investigations. Based on the HTK 80, both the geometric influence of the components, such as the gas inlet and outlet, and the influence of pressures and flow velocities on the flow around the component are to be investigated. In this study we will show the effects of these parameters on the gas flow.


What Effects Have MIM Materials Made on Consumer Electronics Devices?
Mike Guthrie, Foresee
Permanent magnets and magnetic circuits are used in the vast majority of consumer electronics devices; everything from watches and wireless earphones to computers and speakers. It is necessary to conduct and contain the magnetic flux to optimize it’s potential and also to shield it away from susceptible electrical components and vulnerable materials. As these devices are miniaturized, the flux conducting components must also be miniaturized and reshaped. Without MIM technology, these optimization possibilities could not be realized. Example designs will show that the utilization of MIM components has greatly reduced the device size and weight; and also, where only through the utilization of MIM processes have some technologies been made practical.


Heat Cycle Optimization for Additively Manufactured D2 Tool Steel
Mats Persson, Höganäs AB
Tool steels are applied in metal AM, however high carbon level brings additional challenges in selective melting processes. For this reason, maraging steels are more commonly applied in applications requiring hardness and wear resistance. For non-melting, processes these challenges do not apply. Tools steels are readily manufactured by various sintering based processes, including metal injection molding. This paper outlines the implementation of a high carbon cold-work tool steel, D2, for the metal binder jetting process. Material is printed in a Digital Metal® binder jetting printer. Optimization of the sintering cycle has been performed. Furthermore, the effect of various sintering atmospheres, e.g. hydrogen and vacuum, on physical properties and microstructure has been studied. Based on these trials, sintering conditions achieving a density level above 98% have been established, resulting in a hardness level of 38 HRC. Quenching and tempering parameters have been mapped and conditions for achieving typical hardness levels reported for D2 tool steels, i.e. 55-60 HRC. In conclusion, D2 tool steel components are successfully printed by Digital Metal® binder jetting technology. The technology offers, in addition to an increasing array of material, the capacity to both rapidly and cost-effectively produce highly complex and intricate designs.


Binder-Jet Printing: Meeting the Standards of Metal Injection Molding
James W. Sears, Carpenter Technology Corporation
Comparing typical material property results for Binder-Jet Printing to those of Metal Injection Molding (MIM). The typical material properties of several alloys have been published: 316L, 625, H-13 and 17-4PH. In this presentation those publish results along with properties of alloys under development by Carpenter (e.g., CCM, M4, 17-4, 316L, and 625) will be compared to those found in the MIM standards.


Polymer and Powder Characteristics Influencing MIM 2200 (FN02) Rheology and Molding
Dwight Webster, Advanced Metalworking Practices
One method to minimize distortion in MIM is to maximize metal loading. However, for any binder system, as the metal loading increases, material flow and subsequent molding become more challenging. Therefore a feedstock composition must be adapted to meet this need. In this paper we will investigate changes to the composition of a MIM 2200 feedstock, designed for catalytic debinding. We will discuss the influence of changing the metal powder and/or binder formulation on feedstock rheology and molding.


Application of Advanced Materials in 3C Products
Shin Lee, UNEEC
Recent technology trend and requests from communication and electronic industry are getting higher, such as high strength, non-magnetism, high corrosion resistance, high wear resistance, and good surface quality. In this study, materials like F75 (Co-Cr alloy), which is one of the promising candidates for smart phone components, X15 CrMnMoN 17-11-3 (also known as P.A.N.A.C.E.A. by users of BASF SE’s Catamold®), and SUS 17-4PH was manufactured by the metal injection molding (MIM) process. The characteristics and performance such as mechanical strength, magnetism, corrosion resistance, wear resistance, and cost based on different 3C applications were then compared among materials. The comparison trends, conclusions in this study are not fully applicable to all MIM cases, due to differences in raw metal powder grades, solid loading, binder types, manufacturing economic scale, etc., but provide the appropriate directions to pursue.


Breaking up is hard to do – Making up can be harder! (Tales of Atomising and Sintering)
Martin Kearns, Sandvik Osprey Ltd.
As well as having a strong focus on product consistency, Sandvik Osprey has sought over the years to understand more of its customers’ experience of its products through characterisation and customisation of its growing product range. By controlling the alloying, atomising and sizing processes, powder producers can subtly influence the compounding, moulding and sintering behavior in customers’ processes delivering various positive outcomes. In this retrospective, examples are given in case studies on fluidity, strength and surface finish in 17-4PH, high temperature stability in HK30 turbocharger alloy, improved processing windows and tolerance control in tool steels and martensitic stainless steels and the exceptional mechanical properties developed in CoCrMo for dental/medical and Ni base superalloys for aero applications. While primarily relating to MIM, the benefits described are potentially applicable in emerging binder jet technologies where additional emphasis is put on powder flow and packing density.