Design Optimization Through Lithography-based Metal Manufacturing Supporting MIM Applications
Dr. Gyoergy Harakaly, Incus GmbH
Lithography-based Metal Manufacturing (LMM) is a sinter-based additive manufacturing technology that shares key process steps with Metal Injection Molding (MIM), namely debinding and sintering. This similarity arises because both technologies start with a composite of metal powder and a binder system, which defines the shape of the part prior to sintering. As a result, LMM can leverage the metallurgical understanding, material systems, and post-processing strategies developed for MIM, while offering the design flexibility and complexity benefits inherent to additive manufacturing. This commonality makes LMM a natural complement to MIM, while also unlocking unique advantages for part design and production. LMM enables the fabrication of filigree components with surface roughness below 2 Ra, approaching the quality of MIM. By removing the need for mold fabrication, LMM offers significant cost savings in prototyping and design iteration, and extends its value proposition to cost-effective small- and mid-scale production. Furthermore, LMM provides access to design features and geometries that are difficult or impossible to achieve with MIM, broadening the scope of applications. This presentation highlights design strategies tailored for LMM and presents case studies where LMM-enabled designs have successfully transitioned to production scale.
Development of Dual-Color Ceramic Molding Technology
Tomotaka Shimoyama, Tosoh Corporation
Yttria-stabilized zirconia (YSZ) is extensively utilized in structural components, optical fiber ferrules, and grinding media, owing to its superior mechanical strength and fracture toughness. Recently, its translucent white appearance has facilitated its adoption as a dental material.
Concurrently, the demand for YSZ in horological components and jewelry, which leverages its high surface gloss and premium tactile quality post-mirror polishing, has been increasing. For decorative applications, there is a pronounced requirement for diverse chromatic variations, and we have already developed sintered colored zirconia ceramics with a broad spectrum of hues.
Typically, the aesthetic value of colored zirconia decorative components is manifested through morphological design and chromatic selection, although the latter has traditionally been restricted to monolithic coloration. To generate novel aesthetic and functional properties, we have focused on dual-color (multicolor) co-molding technology.
Through comprehensive optimization of the raw powder formulation for both ceramic phases and advancements in sintering protocols, we have established a robust dual-color co-molding technology for colored zirconia ceramics.
This presentation will introduce the newly developed dual-color co-molding technology for colored zirconia ceramics.
Micropowders for MIM and Metal AM
John Johnson, FAPMI, Novamet Specialty Products
Components with features measured in micrometers can be produced by metal injection molding (MIM), but powders with particle sizes significantly smaller than the microfeatures are required. Metal powders with mean particle sizes less than 5 µm can be produced by various processes including hydrogen reduction, hydride/dehydride, carbonyl decomposition, and gas atomization. The typical compositions, sizes, and other characteristics that can be produced by these methods are reviewed. Finer particles increase feedstock viscosity, but it also depends on the particle morphology, which is related to the powder production method. High feedstock viscosity and small part features present challenges for molding and tool construction. Microparts can be produced without tooling via metal additive manufacturing methods such as material extrusion (MEX) and vat photopolymerization (VPP), and their ability to produce them will be compared to that of MIM.
Study of Corrosion on Additive-Manufactured Metals
Braydan Daniels, University of Louisville
The purpose of this study was to investigate and compare the corrosion mechanisms between wrought and additive-manufactured (3D-printed) copper and stainless steel. The experimental procedure applied open circuit potentiometry (OCP), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), Tafel analysis, surface topology, and scanning electron microscopy (SEM) to analyze each metal sample within saltwater, tap water, sulfuric acid, and synthetic body fluid (excluding copper in synthetic body fluid).
Overall, printed stainless steel was more corrosion-resistant than wrought stainless steel in tap water and synthetic body fluid based on OCP, LSV, and surface topology results. Additionally, printed copper was more corrosion-resistant than wrought copper in tap water and 0.5 M sulfuric acid. Thus, printed metals seem to resist corrosion more than their wrought counterpart in tap water.
Based on EIS results of stainless steel, printed stainless steel was found to be more corrosion-resistant than wrought stainless steel in only synthetic body fluid. Although kinetic data showed that printed stainless steel is more corrosion-resistant than wrought in tap water, both corroded at similar rates, so this conclusion can be overlooked. On average, printed and wrought 17-4PH stainless steel corroded the fastest in 0.5 M sulfuric acid, followed by synthetic body fluid, then salt water, and finally tap water. Stainless steel exhibited pitting corrosion in salt water and synthetic body fluid while it experienced uniform (and partial uniform) corrosion in tap water and sulfuric acid.
Based on EIS results of copper, printed copper was more corrosion-resistant than wrought copper in tap water. Although kinetic data showed that printed copper was more corrosion-resistant than wrought copper in salt water and sulfuric acid, both corroded at similar rates for both cases. Therefore, this conclusion can also be neglected. Printed and wrought copper corroded the fastest in 0.5 M sulfuric acid, followed by salt water, then tap water. Copper exhibited uniform (and partial uniform) corrosion in tap water, salt water and 0.5 M sulfuric acid.
Uniformity of Shrinkage in MIM Components
Matt Bulger, ATPM Consulting
There is considerable shrinkage from molding through sinter in the MIM process. If shrinkage is not uniform, then dimensional control issues arise because it will be impossible for all dimensions to be centered on their desired nominal value. Shrink uniformity is discussed for different geometries, including the effect of different processing conditions on dimensional control.