Fine tuning injection feedstock by nano coating SS powder

Barreiros, Fátima M.; Vieira, M.T.; Castanho, José M.

doi:10.1016/s0026-0657(09)70215-2

Cited by 18 publications

(17 citation statements)

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“…The difference between the CPVC value of the 316L in this study and related studies, using similar PSD, which reported values close to 66% [7,14,17,19], can be attributed to the use of different binder type or processing conditions (mixing temperature or speed). The influence of these differences is seen in a related study in which a CPVC of 61% was reported for a 316L stainless-steel powder [20].…”

Section: Optimization Process: Effects Of Powder Typecontrasting

confidence: 50%

“…First, the binder (in a proper volume concentration) was melted inside the chamber (at 175 • C for 5 min) and then metal powders (or powder-MWCNT mixtures) were added. What regards the determination of CPVC, this started with the addition of 50 vol.% of powder to the pre-melted binder and continued through the increments of 1 vol.% powder until the chamber became full; the minimum mixing time for each sequence was considered five min (similar to previous study [14]). Since the Plastograph equipment showed the torque value in real time, it was only proceeded for the next batch when the torque value stabilized (aluminum powders mixing time frequently exceeded the previously fixed five min).…”

Section: Methodsmentioning

confidence: 99%

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Feedstocks of Aluminum and 316L Stainless Steel Powders for Micro Hot Embossing

Emadinia

Vieira

2018

Metals

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In metal powder, shaping the preparation and characterization of the feedstock is an aspect commonly recognized as fundamental. An optimized composition is required to ensure the successful shaping of the feedstock. In this study, a commercial binder system, pure aluminum and 316L austenitic stainless-steel powders were used for micro hot embossing. The optimization process revealed that powder characteristics such as shape and the stability of the torque mixing, were important parameters. Manipulating the feedstock composition by adding multi-walled carbon nanotubes or stearic acid or using a higher powder concentration considerably influenced the torque mixing values. The steady state of torque mixing was achieved for all feedstocks. This torque behavior indicates a homogeneous feedstock, which was also confirmed by microscopic observations. Nevertheless, an extruding process was required for greater homogeneity of the aluminum feedstocks. The presence of the carbon nanotubes increased the homogeneity of green parts and reduced microcrack formation. The roughness was essentially dependent on the feedstock composition and on the plastic deformation of the elastomer die. Shaping the prepared feedstocks (with or without carbon nanotube) was achieved by the optimized powder concentrations and it did not increase by the stearic acid addition.

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Section: Optimization Process: Effects Of Powder Typecontrasting

confidence: 50%

Section: Methodsmentioning

confidence: 99%

Feedstocks of Aluminum and 316L Stainless Steel Powders for Micro Hot Embossing

Emadinia

Vieira

2018

Metals

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“…Moreover, in order to achieve suitable filament flexibility for storage and use in the 3D printer, other polymeric additives were added to the filament feedstock, including a thermoplastic elastomer (TPE) and a plasticizer (P). The optimization of the NiTi filament master binder and additive content was performed using the methodology for powder injection moulding feedstocks by evaluating the critical powder volume concentration (CPVC) [ 21 , 22 , 23 ]. The mixture of NiTi powder particles, master binder, and additives was optimized in a torque rheometer (Plastograph Brabender GmbH and Co., Duisburg, Germany) with a selected rotation blade speed of 30 rpm at a temperature of 180 °C.…”

Section: Methodsmentioning

confidence: 99%

In Search of the Optimal Conditions to Process Shape Memory Alloys (NiTi) Using Fused Filament Fabrication (FFF)

Carreira

Cerejo²,

Alves

et al. 2020

Materials

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This research was performed so as to investigate the additive manufacturing of NiTi shape memory alloys, which is associated with direct processes, such as selective laser melting. In addition to its expensive production costs, NiTi readily undergoes chemical and phase modifications, mainly as a result of Ni loss during processing as a result of high temperatures. This research explores the potential usefulness of NiTi as well as its limitations using indirect additive processes, such as fused filament fabrication (FFF). The first step was to evaluate the NiTi critical powder volume content (CPVC) needed to process high-quality filaments (via extrusion). A typical 3D printer can build a selected part/system/device layer-by-layer from the filaments, followed by debinding and sintering (SDS), in order to generate a near-net-shape object. The mixing, extruding (filament), printing (shaping), debinding, and sintering steps were extensively studied in order to optimize their parameters. Moreover, for the sintering step, two main targets should be met, namely: the reduction of contamination during the process in order to avoid the formation of secondary phases, and the decrease in sintering temperature, which also contributes to reducing the production costs. This study aims to demonstrate the possibility of using FFF as an additive manufacturing technology for processing NiTi.

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“…The procedures applied in these processes depend on the binder material and powder type. The binder can be partially removed either by the application of a dissolving or by a thermal process and then passed for a complete decomposition process (before heating to higher temperatures) combined with the sintering step [32,33]. This is called secondary debinding and sintering approach.…”

Section: Input Materialsmentioning

confidence: 99%

“…The four feedstock revealed torque values < 2N [30] Gradual addition procedure during mixing torque CPVC = 62% PL = 60% [8,13,24,27] Gradual addition procedure during mixing torque 16,29] Gradual addition procedure during mixing torque CPVC = 62% PL = 60% [34] The value of the powder and binder content in feedstock (determined as PL) also affects the performance of debinding and sintering. An excess binder does not retain the shape after debinding [32]. Moreover, there is a minimum powder content that can ensure contact between the powders to create sintering necks between them, which leads to a final consolidation [40].…”

Section: Semicrystallinementioning

confidence: 99%

Development of Metal Powder Hot Embossing: A New Method for Micromanufacturing

Sequeiros

Emadinia

Vieira

et al. 2020

Metals

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Hot embossing is a small-scale, low-cost processing technology that can deliver products to the market in a short time. This microreplication technology is well established to produce polymeric components and has applications in several industrial sectors. The use of micropowder hot embossing in the production of metal components is an emerging and challenging process that, when compared to other typical technologies, brings some economic advantages in a volatile market with an increasing tendency to manufacture customized products. The main objective of this review is to analyze the potential of powder hot embossing and its developments in the production of metallic microparts/components. This technology requires four distinct steps: (1) production feedstock (preparation of mixtures), (2) hot embossing (shape forming), (3) debinding and (4) sintering. These steps are interrelated and influence the characteristics of the final metallic microparts. This study summarizes the approaches implemented for the use of different metallic powders and polymeric binder systems for the preparation of the feedstock, the mold materials and the critical conditions tested in the embossing step to produce green parts, and the production of the final parts through the application of debinding and sintering. Powder hot embossing is a viable replication technology that allows the production of new metallic microcomponents, contributing to the global scientific effort of miniaturizing manufacturing process, equipment and products. The merit of powder hot embossing for industrialization needs further development to assert itself in the market and compete with other micromanufacturing techniques.

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Fine tuning injection feedstock by nano coating SS powder

Cited by 18 publications

References 0 publications

Feedstocks of Aluminum and 316L Stainless Steel Powders for Micro Hot Embossing

Feedstocks of Aluminum and 316L Stainless Steel Powders for Micro Hot Embossing

In Search of the Optimal Conditions to Process Shape Memory Alloys (NiTi) Using Fused Filament Fabrication (FFF)

Development of Metal Powder Hot Embossing: A New Method for Micromanufacturing

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