Optimisation of microwave-oven assisted debinding of material extrusion additive manufactured 316 L stainless steel samples

Metal powder filters are key components in semiconductor manufacturing equipment that play a critical role in preventing the ingress of impurities and fine particles that may be contained in process gases. With the increasingly advanced development of the semiconductor industry, metal powder filters also require more precise and advanced performance. Therefore, in this study, a filter with a honeycomb structure morphology with crossed top and bottom was fabricated by a material extrusion additive manufacturing (MEAM) process. To achieve this, the prepared pellets were subjected to the MEAM, allowing the creation of filters with complex shapes featuring crossed top and bottom structures. After polishing the surface of the specimen, solvent debinding and thermal debinding were performed to remove the binder. Solvent debinding was performed in n-Heptane for 24 hours, while thermal debinding was performed in an Ar atmosphere at a maximum temperature of 800°C. The debinded specimens were sintered under a high vacuum atmosphere at temperatures of 850°C, 950°C, and 1050°C, respectively. The prepared metal powder filters were examined for filter morphology and microstructure using optical microscopy, and pore properties such as porosity and air permeability were evaluated.

Debinding is a critical process for injection molded green parts of soft magnetic materials. In case of incomplete binder removal, the residual impurities deteriorate the magnetic performance of the final components. On the other hand, binder decomposition reduces the structural strength of the green parts. Therefore, it is important to engineer an appropriate debinding cycle not only to ensure efficient binder removal but also to retain the structural strength of the parts. In this study, the two-stage debinding process is optimized focusing on the higher rate of binder removal to get defect-free parts. The feedstock of Fe–50Ni alloy with a multicomponent binder system was prepared followed by injection molding. In the first stage, the binder was removed by solvent debinding and in the second stage, thermal debinding was carried out. The various types of defects were observed during debinding process. It has been found that efficient solvent debinding extracted 98% binder whereas thermal debinding at a heating rate of 2 °C min−1 results in defect-free quality parts.

Impact of strand deposition and infill strategies on the properties of monolithic copper via material extrusion additive manufacturing

Thermal debinding processing of 316L stainless steel powder injection molding compacts

Additive Manufacturing or Direct Manufacturing, popularly known as 3D Printing, has become the leading-edge manufacturing technology. Today Metal Additive Manufacturing (MAM) is a reality, not only for prototype fabrication, also for functional parts in all industrial sectors. Design freedom that the AM processes offer has led to design and engineering of new, complex, light-weight structures in all applications. However, in order to realize further and widespread use of metal AM for manufacturing critical components, it is necessary to explore the inherent material freedom in AM. While new metal AM materials are being developed, the role of Materials Science and Engineering (MSE) is becoming more apparent than ever before. This presentation will highlight the increasing role of Materials Science and Engineering in metal AM technologies. This presentation will show the essence of metallurgical principles in realizing full scope of material freedom in metal additive manufacturing. This presentation will demonstrate how fundamental MSE principles can be utilized to develop new materials, optimize metal AM and post processing, and their controls that cannot be achieved by conventional manufacturing methods. The examples with new AM alloys based on Al, Ti, and Ni will be presented, leading to a path of developing advanced and higher performance products for critical applications.

The mechanisms of thermal, solvent, and vacuum debinding processes for powder injection molded (PIM) compacts were investigated. Mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) observations on PIM specimens showed that fine interconnected pores were developed in the early stages of debinding in all three processes. These pores were formed as a result of the decomposition of low temperature binders such as paraffin wax during thermal debinding or arise from the extraction of soluble binder components in solvent debinding. In the later stages of thermal and vacuum debinding, decomposed gases could be trapped in the center region and build up a pressure causing cracking or blistering defects. The solvent debinding process could alleviate these problems, but the penetration of solvent into the binder could still cause cracking or distortion due to swelling of the binder. It was found that the pore structure evolution was influenced by the heating rate, temperature, pore size, and the amount of existing porosity. From the observed microstructure and mercury porosimetry data, debinding mechanisms were derived and the defects which were frequently seen during debinding were explained with these mechanisms.

Metal based additive manufacturing methods using lasers are widely used in a variety of industries and applications. 3D printing, the metal powder bed based process and laser cladding are amongst the most commonly known means of metal AM. With the use of lasers the process chain metal AM can be extended offering unique advantages for process optimization.The combination of AM processes with conventional manufacturing allows for a cost and process optimized design. While many parts can be printed completely it might not be efficient for parts of the geometry. There the use of conventionally manufactured performs can reduce printing time and cost, the complex structure is then printed onto that perform.Another step towards process optimization is to combine AM technologies, using 3D printing for complex hollow structures and LMD for the solid part of a turbine blade is a prime example of fine tuning AM for maximum efficiency.Lasers can also be used in post processing of AM components. As each part that has been produced with an AM process requires surface treatments to enhance flow, fatigue strength or just appearance the laser can offer solutions.From surface re-melting of a laser clad part to area specific laser polishing the laser can be used to enhance part performance when and where it is needed and to the level required.Lasers in AM further enhance the capabilities of the already versatile processes and will help in further advancing the acceptance of metal based AM as viable tool of the trade.Metal based additive manufacturing methods using lasers are widely used in a variety of industries and applications. 3D printing, the metal powder bed based process and laser cladding are amongst the most commonly known means of metal AM. With the use of lasers the process chain metal AM can be extended offering unique advantages for process optimization.The combination of AM processes with conventional manufacturing allows for a cost and process optimized design. While many parts can be printed completely it might not be efficient for parts of the geometry. There the use of conventionally manufactured performs can reduce printing time and cost, the complex structure is then printed onto that perform.Another step towards process optimization is to combine AM technologies, using 3D printing for complex hollow structures and LMD for the solid part of a turbine blade is a prime example of fine tuning AM for maximum efficiency.Lasers can also be used in post processing of AM components. As each part that has ...

Unsatisfactory dimensional control, distortion, and defects are frequently observed in powder-injection-molded parts, particularly after the solvent and thermal-debinding processing steps. One of the reasons is that the amount of soluble binder removed during the first step, solvent debinding, is not great enough to form interconnected pores throughout the compact, particularly in the core region. Thus, blistering, cracking, and bubbles can form easily during the subsequent thermal debinding. To determine the minimum debinding fraction required for solvent debinding, at which point interconnected pore channels are formed at the center, modeling of the distribution of the remaining soluble binder in the compact was established. The actual distribution, which was obtained by measuring the binder content layer by layer with the soxhelt extraction method, is in good agreement with the model. The modeling, bubble test, and fluorescence dye-penetration analysis show that, regardless of the compact thickness, the minimum bulk debinding fraction needed is consistently approximately 59 pct, yielding a local debinding fraction of 37 pct and a porosity of 8.5 pct at the center. This porosity is close to the value at which pores in a sintered compact transform from open to closed at the beginning of the final stage of sintering.

Fused filament fabrication, debinding and sintering as a low cost additive manufacturing method of 316L stainless steel

The metal injection mold (MIM) process is the most cost effective, highest quality means to produce complex shaped, high performance parts. In the MIM process, debinding is a key step for successful MIM. However, the conventional debinding processes, which are thermal debinding and solvent debinding, have disadvantages that include long product development times, and harm to the environment. Therefore, the study of supercritical CO2 that can be used as solvent for debinding, a new debinding technology as substitute for a conventional technology, was considered. In this paper, we used two methods to investigate a method for reducing debinding time as well as lowering operation condition other than pure supercritical CO2 debinding: the first method was to add cosolvent in supercritical CO2, the second method was to use the mixture of propane + CO2, as the supercritical solvent. It was found that the addition of cosolvents and the use of binary mixture propane + CO2 for supercritical solvent remarkably improved the binder removal rate, in comparison with using pure supercritical CO2.

Additive manufacturing (AM) is a trending technology that is being adopted by many companies around the globe. The high level of product customization that this technology can provide, added to its link with key green targets such as the reduction of emissions or materials waste, makes AM a very attractive vehicle towards the transition to more adaptive and sustainable manufacturing. However, such a level of customization and this fast acceptance, raise new needs and challenges on how to monitor and digitalize the AM product life cycles and processes, which are essential features of a flexible factory that address adaptive and first-time-right manufacturing through the exploitation of knowledge gathered with the deep analysis of large amounts of data. How to organize and transfer such amounts of information becomes particularly complex in AM given not just its volume but also its level of heterogeneity. This work proposes a common methodology matching with specific data formats to solve the integration of all the information from AM processes in industrial digital frameworks. The scenario proposed in this work deals with the AM of metallic parts as a specially complex process due to the thermal properties of metals and the difficulties of predicting defects within their manipulation, making metal AM particularly challenging for stability and repeatability reasons but at the same time, a hot topic within AM research in general due to the large impact of such customized production in sectors like aeronautical, automotive, or medical. Also, in this work, we present a dataset developed following the proposed methodology that constitutes the first public available one of multi-process Metal AM components.KeywordsAdditive manufacturingDigitalizationDataset

In the present work the influence of two different thermal debinding atmosphere, vacuum and air, on the properties of 5wt% Y2O3-doped aluminum nitride (AlN) ceramics was investigated. The AlN powder as a raw material was synthesized by self-propagating high-temperature synthesis (SHS) and compact was fabricated by employing powder injection molding technique. The polymer-wax binder consists of 60wt% paraffin wax (PW), 35wt% polypropylene (PP) and 5wt% stearic acid (SA). The binder was removed through debinding process in two steps, solvent debinding followed by thermal debinding. After the removal of binder, specimens were sintered at 1850˚С in nitrogen atmosphere at atmospheric pressure. The result reveals that debinding atmosphere has significant effect on the thermal conductivity and densification of AlN ceramics. The microstructure and secondary phase identification was determined by scanning electron microscopy and X-ray diffraction. The thermal conductivity and density of injection molded AlN ceramics are 177.3W·m-1·K-1 and 3.31g·cm-3 in the air and 200.8W·m-1·K-1 and 3.28g·cm-3 in the vacuum.

Metal Additive Manufacturing (MAM) process has been established as an industrial process for customized and intricate metallic components. It is one of the growing technologies proving its potential in numerous fields by introducing the latest processing methods. The significant growth in this technology is partially fueled by its ability to manufacture parts that could be performance-beneficial and commercially utilizable in various industries. The adaptability of metal AM processes has prompted innovation across various industries with applications spanning defense, aerospace, medical, dental, automotive, and oil & gas sectors. Each industry benefits from the unique abilities of metal AM; for instance, material efficiency, design flexibility, lead time reduction, and the creation of lightweight and complex structures that were unachievable through traditional methods can now be achieved. Therefore, this review article analyzes metal AM, describing its types, technological challenges, environmental & business considerations, energy consumption, applications, and future trends. Initially, the article introduces primary categories of metal AM, elaborating their mechanism and working principles, later, it focuses on the industrial contributions of metal AM, technological challenges, and business considerations. The outlook of this technology highlights emerging materials and technologies, such as the inclusion of machine learning (ML) and artificial intelligence (AI) to predict defects, optimize process parameters, and enhance the quality of products. Furthermore, advanced materials like high entropy alloys (HEAs) are being discussed to broaden the functionality of AM parts. Metal AM is playing a critical role in shaping the future of manufacturing by offering customization, efficiency, and sustainability in the industries. The article aims to provide a general understanding of metal AM while highlighting key technological advancements and future research directions to expand its applications in various sectors further.

Thermogravimetric and binder removal analysis of injection moulded reinforced ceramic composite

Binder removal via a two-stage debinding process for ceramic injection molding parts