Paste Formulation Research Articles

ПЕРСПЕКТИВЫ ИСПОЛЬЗОВАНИЯ ВТОРИЧНЫХ СЫРЬЕВЫХ РЕСУРСОВ ДЛЯ ПРОИЗВОДСТВА ДЕСЕРТОВ

The paper presents the implementation of non-waste technologies into food production at food industry and catering enterprises on the example of the production of desserts with the use of buckwheat husk as secondary raw materials. The use of secondary raw materials as food ingredients is aimed at reducing unused and non-recyclable waste generated during the processing of grain raw materials into groats and flour. The husk yield depends on the buckwheat variety, growing conditions and other factors and averages from 14 to 30 %. Despite the high content of biologically active substances in the husk and its high availability, its use in food production is limited. The formulations and technologies for the desserts with different contents of buckwheat husk powder were developed and substantiated in the present research. For the use as a food additive, buckwheat husk was processed into the form of a fine mechanically activated powder. Buckwheat husk powder was introduced into the chocolate-nut paste formulation in the amount of 10 %, 20 %, and 50 % of cocoa powder. The dessert samples were evaluated on their sensory characteristics and nutritional value. It was found that the use of buckwheat husk powder in the chocolate-nut paste formulation has a positive effect on its sensory characteristics, among which the aroma harmony and saturation, as well as the taste harmony, stand out. The dietary fiber, calcium, magnesium and iron content in 100 g of the dessert sample was above 15 % from the adequate level of their daily norm. Thus, the developed dessert formulation based on chocolate-nut paste with buckwheat husk has high sensory characteristics and increased nutritional value with functional properties and can be recommended for production and sale at catering enterprises.

Review on Formulation of Polyherbal Toothpaste Using Medicinal Plants

Toothpaste is a gel or paste formulation product and is use to clean and maintain oral hygiene with the aid of toothbrush. But some of these substances show undesirable side effects such as tooth staining and altered taste. India is that the largest producer of healthful herbs and is termed the “Botanical Garden of the world”. The objective of the present review to formulate herbal toothpaste containing natural ingredients like clove fruit, Neem leaves, Honey and Acacia powder, Betel, Peppermint, Turmeric, Guava etc. which were traditionally used for tooth cleaning. They not only show antimicrobial property for naturally action diseases however even have essential concentration of bound phytochemical present in them which will profit our body in some ways. Based on increased usage of herbal cosmetics we tried to make a comprehensive review on herbal toothpaste that helps to maintain a proper oral hygiene and free from periodontal disorder, reduce stain, gingivitis, calculus and caries. The present review gives basic information regarding antimicrobial potential of various herbs, formulation excipients, that can be used in preparation of toothpaste. Herbal toothpaste which can be used as a tool for proper oral hygiene and to overcome the side effect of the conventional toothpaste by synthetic ingredients.

Antibacterial and osteoinductive properties of wollastonite scaffolds impregnated with propolis produced by additive manufacturing

Biocompatible ceramic scaffolds offer a promising approach to address the challenges in bone reconstruction. Wollastonite, well-known for its exceptional biocompatibility, has attracted significant attention in orthopedics and craniofacial fields. However, the antimicrobial properties of wollastonite have contradictory findings, necessitating further research to enhance its antibacterial characteristics. This study aimed to explore a new approach to improve in vitro biological response in terms of antimicrobial activity and cell proliferation by taking advantage of additive manufacturing for the development of scaffolds with complex geometries by 3D printing using propolis-modified wollastonite. The scaffolds were designed with a TPMS (Triply Periodic Minimal Surface) gyroid geometric shape and 3D printed prior to impregnation with propolis extract. The paste formulation was characterized by rheometric measurements, and the presence of propolis was confirmed by FTIR spectroscopy. The scaffolds were comprehensively assessed for their mechanical strength. The biological characterization involved evaluating the antimicrobial effects against Staphylococcus aureus and Staphylococcus epidermidis, employing Minimum Inhibitory Concentration (MIC), Zone of Inhibition (ZOI), and biofilm formation assays. Additionally, SaOs-2 cultures were used to study cell proliferation (Alamar blue assay), and potential osteogenic was tested (von Kossa, Alizarin Red, and ALP stainings) at different time points. Propolis impregnation did not compromise the mechanical properties of the scaffolds, which exhibited values comparable to human trabecular bone. Propolis incorporation conferred antibacterial activity against both Staphylococcus aureus and Staphylococcus epidermidis. The implementation of TPMS gyroid geometry in the scaffold design demonstrated favorable cell proliferation with increased metabolic activity and osteogenic potential after 21 days of cell cultures.

Design of sol-gel bioactive glasses: Towards tailored architecture and ion-supply for bone tissue regeneration

This paper reports the synthesis of borosilicate bioactive glasses nanoparticles containing ions of interest (calcium, strontium or silver ions) for the purpose of bone tissue regeneration using a modified Stöber method and their shaping by robocasting to produce macroporous grid-like architectures with controlled interconnected porosity. Main focus is on the design of a paste formulation, the optimization of the robocasting process to produce 3D scaffolds and ion release from the sintered scaffold in solution. Pastes were developed (40 vol% powder loading), characterized, and extruded layer-by-layer to form three-dimensional scaffolds with a grid-like macrostructure (400 μm diameter of the rods). After drying under controlled atmosphere, scaffolds were sintered. The sintering study revealed that the addition of silver reduced the densification point of the borosilicate glass. After immersion in a buffer solution, ionic release (Si, B and Sr) of the sintered scaffold was evaluated, and compared with the synthetized powder. The shaping process did not affect Sr dissolution. This controllable ion-release behavior of the scaffolds are promising for their therapeutic application.

Tailoring Morphology and Size of Silver Nanoparticles Prepared by Polyol Method by Changing the Structure of Silver Carboxylate Precursor

AbstractSilver nanoparticles are synthesized by reducing silver alkyl carboxylates at their high concentrations with ethylene and propylene glycol without a common use of polymeric dispersants and stabilizers. The effects of alkyl chain structure on the morphology and size of silver particles have been studied by scanning electron microscopy, transmission electron microscopy, powder X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analyses. The carboxylates that have been investigated are silver caprylate, laurate, 2‐butyloctanoate, and 2‐ethylhexanoate. It was found that the reduction temperature of straight‐chain alkyl carboxylates is in the 110–120 °C range. The particles prepared under these conditions are perfectly spherical in shape and their average size varies from 20 to 40 nm. In the case of the branched structure, the reduction process starts at around 80 °C and produces irregularly shaped silver particles with a size of 150 to 450 nm. Possible ways of controlling the parameters of the synthesized nanoparticles are proposed. This study proposes a simple and easily scalable method to prepare silver nanoparticles stabilized by a non‐polymeric stabilizer. The as‐synthesized silver particles may have applications as metallic fillers in ink and paste formulations for 2D and 3D printing to fabricate functional components and devices.

Optimization of spicy red pepper paste (Awaze) formulation by D-optimal mixture design.

The aim of this study was to produce spicy red pepper paste (Awaze) by addition of various sources of antioxidant, mineral, and fiber and optimize betterprocessing methods of the paste. For this purpose, D-optimal mixture design was used, Awaze considering color value (a*), antioxidant content, mineral content, fiber content, chewiness, and viscosity of the paste as the main parameters. Various properties of the optimized formulation were evaluated. The optimal formulation contained 65.66% red pepper, 10% garlic, 19.08% red onion, and 5.25% ginger. In the optimized formulation, the redness value (a*) increased by more than 3.12 times compared to the control with the average antioxidant activity (44.6%). The optimal formulation had a higher fiber content, chewiness, and viscosity value compared to control which is probably related to the ingredient proportion difference. Due to the higher nutritional and processing quality obtained, this formulation can be suggested for commercial and household producers as a guide to manufacture Awaze. The results obtained indicate that it is possible to production of Awaze with high nutritional value and improved processing quality by utilizing a blend of red pepper, garlic, red onion, and ginger. Therefore, this formulation stands as a viable recommendation for both commercial enterprises and household producers due to its demonstrated ability to yield Awaze with enhanced nutritional content and superior processing quality.

Thixotropy and printability study of intense pulsed light sinterable copper paste formulations for flexible substrates

At present, most of the reported articles on IPL sintering of flexible copper paste focus mainly on the effects of IPL sintering parameters and copper powder modification methods on conductive copper patterns, which ignores the influence of thixotropy, printing and other properties that are of great concern in industrial production on the conductive copper pattern. In this article, four resin materials with distinctive mechanical properties, heat resistance, and stability are selected to develop a flexible copper paste formulation for IPL sintering. By focusing on the thixotropy and printing properties of different flexible copper pastes formulations, we found the relationship between these two properties and the performance of conductive copper patterns. The results show that thixotropy property affects the printing property, and the printing property affects the density and boundary definition of the conductive copper pattern film layer after sintering, thus affecting the conductivity. Finally, we obtained a flexible copper paste formulation suitable for IPL sintering with a printed line width of 35.47 μm, a line space of 31.55 μm, and a square resistance of 15.7 mΩ/◻.

Development of new formulation for soft material in paste extrusion-based 3D Printer

Fused Deposition Modelling is a form of additive manufacturing where solid filament is heated into molten state and deposited onto a heating platform to create three-dimensional objects layer-by-layer. Since heating and cooling processes are involved in Fused Deposition Modelling (FDM), this restricts the use of thermoplastic polymers such Room Temperature Vulcanizing (RTV) silicones and gels. Others concern are with the right rheological properties for extrusion and the ability to provide desired mechanical qualities upon quick solidification. To develop a suitable silicone printing technology, it is crucial to understand the silicone polymerization mechanism in terms of its rheological and mechanical characteristics. Due to the numerous factors that can influence silicone paste mixtures, this study utilized the Taguchi method to design experiments, optimize factors, and predict properties, thereby avoiding extensive and resource-intensive experimental work. The study specifically considered the factors of curing method, mass ratio of silicone thinner, and fumed-silica in the silicone paste formulation. Among the 9 samples generated through the Taguchi method, only one sample demonstrated favourable results in terms of mechanical properties and the curing process, with a mixture ratio of base silicone, silicone thinner, and fumed-silica at 15g, <1g, 0.1g; respectively. However, further investigation into the fixed amount of silicone and fumed silica in the selected mixture ratio indicate that the amount of silicone thinner must be less than 1g or can be omitted as the silicone paste can be used as printing ink for the extruder. The shore hardness testing for the silicone samples revealed with zero percent silicone thinner exhibited a hardness value of 21.5 HA (Shore A) while the sample obtained less than 1g displayed a significantly lower hardness value of 10.5 HA. These findings indicate that the addition of silicone thinner in the silicone paste formulation, as optimized through the Taguchi method, contributed to a reduction in the hardness of the material for shore A scale. This suggests that the presence of silicone thinner affects the elasticity and flexibility of the silicone paste, resulting in a lower Shore hardness value. The discrepancy in hardness values between the samples further highlights the significance of formulation optimization to achieve desired material properties for silicone paste-based applications in 3D printing.

3-D printed meat alternatives based on pea and single cell proteins and hydrocolloids: Effect of paste formulation on process-induced fibre alignment and structural and textural properties

Extrusion-based 3D food printing can be used as an alternative structuring technique to traditional extrusion processing for creating meat-like structures. This study focused on 3-D food printing to generate structures analogous to meat by using various combinations of texturized pea protein fibrils, microbial Single Cell Protein (SCP) and hydrocolloids locust bean gum and/or sodium alginate. Simple moulding was utilized as benchmarking to better understand the 3D printing-induced structural effects. To gain understanding of the interactions between proteins of different origin (plant and SCP) and with hydrocolloids, structural, textural and rheological properties were analysed. Oscillatory stress sweeps of all printing pastes revealed elastic-dominant rheological behaviour (G′ 4000–6000 Pa) with a defined yield stress (25–60 Pa) explaining their printability and shape stability. X-ray microtomography of ion-crosslinked analogues showed a printing-induced preferential alignment of fibrils in the direction of nozzle movement, while moulding led to a random orientation. Textural characterization via bi-directional cutting tests demonstrated higher cutting force in transversal (FT) over longitudinal (FL) direction in 3D-printed samples and equal forces in moulded samples. The anisotropy index (AI = FT/FL) of printed samples ranged between 1.4 and 2.5, indicating anisotropic texture, and 0.8–1 for moulded samples indicating isotropic texture. This study demonstrated the applicability of paste-extrusion in generating anisotropic structures analogous to meat by process-induced fibril alignment. The results support further development of 3D food printing technology in design of sustainable meat alternatives resembling whole-muscle meat.

Non-toxic flexible screen-printed MWCNT-based electrodes for non-invasive biomedical applications

Here, a non-toxic, flexible, low-cost, and disposable multiwalled carbon nanotube (MWCNT)-based screen-printed electrode (SPE) was developed for non-invasive health monitoring applications. A novel MWCNT-based conductive paste formulation was prepared and optimized for printing SPEs using a computer numerical control (CNC)-made stencil. The electrodes were electrochemically characterized and subjected to physical stress to investigate their mechanical durability in extreme situations such as heavy exercise. The reproducibility of the fabrication approach and the stability of the electrodes were also demonstrated. The electrochemical performance of the electrodes was tested with first dopamine (DA) and then glucose. The SPE displayed a linear response in the DA concentration range of 5–500 μM with a limit-of-detection (LOD) of 0.87 μM. Detection of glucose was carried out based on electrochemical-enzymatic redox cycling in artificial sweat; wherein the flexible SPE-based biosensor exhibited a linear response, particularly up to 1 mM with an LOD of 31.7 μM. It is likely that the high sensitivity was achieved due to the large surface-to-volume ratio of MWCNTs and micro/nanoporous network morphology of the electrode surface which was observed in scanning electron microscopy (SEM). Cytotoxicity tests confirmed that the flexible MWCNT-SPEs are non-toxic and therefore safe for non-invasive health monitoring. As a result, the electrodes displayed excellent electrochemical behavior and are expected to contribute to wearable sensor technology due to features such as high stability, sensitivity, flexibility, and non-toxicity.

A Novel Herbal Paste Formulation of Turmeric, Tulsi, and Honey for the Treatment of Oral Submucous Fibrosis.

Background and objectives Oral submucous fibrosis (OSMF) is a condition that affects the oral cavity and is characterized by the development of fibrous bands in the submucosal layers, leading to progressive difficulty in mouth opening and other symptoms. Inflammation and advancing fibrosis of the submucosal tissues are the hallmarks of this chronic, disabling illness of the oral cavity. The disorder is well known for having a propensity for cancer and is particularly linked to the habit of chewing tobacco and areca nuts. The study mentioned aims to compare the effectiveness of a novel herbal paste formulation containing turmeric, tulsi (holy basil), and honey in managing OSMF. The use of herbal remedies is common in traditional medicine, and turmeric and tulsi are known for their potential anti-inflammatory and antioxidant properties. Honey, too, is believed to have some therapeutic benefits. Methodology A study was conducted at MNR Dental College and Hospital, Sangareddy, Telangana, India, in the Department of Oral Medicine and Radiology (OMR) on 80 oral submucous fibrosis patients to evaluate the efficacy of a novel herbal paste formulation of turmeric, tulsi, and honey, comprising 77 males and three females. Patients were given a novel herbal paste formulation consisting of 10 g of turmeric powder and 10 g of tulsi powder, mixed in 10 ml of honey, to study subjects, and a placebo consisting of anti-oxidants was administered to control subjects for three months. The subjective and objective symptoms were recorded and statistically analyzed. Results The majority of the subjects were in the age group of 18-22 years, with an average age of 28.09+/-8.38 years with the most predominant habit of gutka chewing. A statistically significant change in the mouth opening, tongue protrusion, burning sensation, blanching of the mucous membrane, and reduction in palpable fibrous bands was found in the study subjects when compared to control subjects. Conclusion The present study evaluated the efficacy of a novel herbal paste formulation of turmeric, tulsi, and honey in the management of OSMF.

Effect of rheology and cooling on paste extrusion using texture analysis

Extrusion of pastes from squeezable tubes is a ubiquitous but complex process, and it is not well studied. A common example is toothpaste, which needs to be easily extrudable from its tube, but it is not always the case due to the complex rheology of the paste. This may be particularly problematic if the base liquid in the formula is anhydrous leading to the paste hardening at temperatures close to ambient. In this work, we use various testing techniques to study the squeezability of the tubes containing hydrous and anhydrous paste formulations. We show that mechanical testing imitating human hand operation adequately predicts the actual sensorial panel data while also correlating with simple viscosity measurements. Furthermore, for anhydrous pastes sensitive to cooling their effective hardening temperature may be predicted by thermal analysis of their base liquids. Overall, it is expected that the results and the methodologies presented in this work will be of good guidance for product/packaging developers.

Paste Development for an Optimized Filament Stretching Effect during Parallel Dispensing on Transparent Conductive Oxide Layers for Solar Cell Metallization

The availability of silver as an electrically conductive filler material in printing pastes for solar cell metallization is becoming a more crucial issue for multiterawatt‐scale production due to its global constraints. Therefore, the silver consumption for solar cell production needs to be reduced drastically by substituting silver with alternative conductive filler materials or utilizing process‐specific phenomena. The phenomenon of filament stretching during microextrusion allows significantly lower paste laydowns. The magnitude of filament stretching is paste‐dependent and therefore further knowledge of the pastes’ impact to the filament stretching is required. This study presents nine low‐temperature curing pastes differing in the particle system and binder resin. The rheological and thermal behavior of these suspensions are investigated and printing tests onto silicon heterojunction (SHJ) precursors are carried out. Additionally, scanning electron microscopy (SEM)‐based microstructure analyses of printed electrodes are performed. Based on these experimental results, the impact of paste compositions regarding the paste behavior during microextrusion and the SHJ solar cell performances are analyzed. The developed paste formulations exhibit a strong filament stretching, leading to a reduced silver laydown of down to ΔmAg = −60%rel. and an absolute efficiency gain of up to Δη = +0.75%abs. due to less shading losses.

Sugarcane bagasse ash as a partial replacement for cement in paste and mortar formulation – A case in the Philippines

The quality of sugarcane bagasse ash (SCBA) varies significantly from one locality to another. It greatly influences its performance when used as cement replacement, thus requiring actual empirical data to be generated. This research explored the potential of locally available SCBA in the Philippines as a partial cement replacement material and assessed the appropriate formulations of the paste component with SCBA as part of the cement to be used for mortar and concrete production in the future. Mixtures with different SCBA-to-binder ratios (SBR) up to 20%, and water-to-binder ratios (WBR), were formulated to determine their effects on the consistency and setting time of paste, consistency of fresh mortar, density, and compressive strength of hardened mortar. Multivariate regression analysis was adopted to better interpret the influence of SBR and WBR on the different responses and generate models for their subsequent prediction, including the water requirement, to achieve normal consistency. It was found that increasing SBR from 0.00 to 0.20 increased the water demand for the paste from 0.27 to 0.36 WBR. An increase in the WBR subsequently increases the initial setting time to as much as 198 ± 16 min and the final setting time to 288 ± 4 min. The water demand for mortars also increased with increasing SBR to achieve the same workability. Generally, the models generated enabled good predictability (≥90% accuracy) of the water requirements of both paste and mortar. The density and compressive strength of mortars improved with SBR at 0.05 but then decreased as the SBR was increased. However, mixtures with SBR at 0.10 reached a compressive strength comparable to mixtures with pure cement, rendering the maximum amount that the cement can be replaced at 10%.

A novel strategy for fabrication, activation and cleaning of fully 3D printed flexible planar electrochemical platforms

AbstractIn recent years, 3D printing of carbon‐based conductive filaments has received growing attention for assembling electrodes to be used in a wide variety of electroanalytical devices and applications. Despite the large amount of work present in literature concerning the development of three‐dimensional (3D) conductive structures, its potential as dry deposition method for assembling two‐dimensional (2D) electrodes to be used in planar configuration is still largely unexplored. In fact, the possibility to rapidly change the geometry of the electrochemical circuits, associated with the reduction of waste and the absence of solvents, which are instead important components of ink and paste formulations, makes this strategy a valid green and efficient alternative to other deposition approaches such as screen‐printing technology. We report here a rapid and solvent‐free method for assembling fully 3D printed flexible planar electroanalytical platforms (3DEPs) to be used with microliters of liquid. At the same time, a novel protocol for the surface pre‐treatment of 3D printed electrodes based on ultrasonication in aqueous NaOH solution followed by electrochemical activation using the same medium, is presented. In addition, the same procedure has proved to be efficient for cleaning the electrode surface after electrochemical passivation, thus confirming the validity of both time‐efficient and environmentally‐friendly assembling and activation/cleaning procedures developed which allow efficient and reusable electrodes to be produced. Finally, 3DEPs were tested by a proof‐of‐concept quantification of a commonly used food dye (Brilliant Blue, E‐133) in commercial solutions used for homemade food coloring.

3D screen printing technology enables fabrication of oral drug dosage forms with freely tailorable release profiles

3D printing offers new opportunities to customize oral dosage forms of pharmaceuticals for different patient populations, improving patient safety, care, and compliance. Although several notable 3D print technologies have been developed, such as inkjet printing, powder-based printing, selective laser sintering (SLS) printing, and fused deposition modelling (FDM), among others, their capacity is often limited by the number of printing heads. 3D screen-printing (3DSP) is based on a classic flatbed screen printing that is widely used in industrial applications for technical applications. 3DSP can build up thousands of units per screen simultaneously, enabling mass customization of pharmaceuticals. Here, we use 3DSP to investigate two novel paste formulations: immediate-release (IR) and extended-release (ER) using Paracetamol (acetaminophen) as the active pharmaceutical ingredient (API). Both disk-shaped and donut-shaped tablets were fabricated using one or both pastes to design drug delivery systems (DDS) with tailored API release profiles. The size and mass of the produced tablets demonstrated high uniformity. Characterization of the tablets physical properties, such as breaking force (25–39 N) and friability (0.002–0.237%), adhering to Ph. Eur (10th edition). Finally, drug release tests with a phosphate buffer at pH 5.8 showed Paracetamol release depended on the IR- and ER paste materials and their respective compartment size of the composite DDS, which can be readily varied using 3DSP. This work further demonstrates the potential of 3DSP to manufacture complex oral dosage forms exhibiting custom release functionalities for mass production.

Determination of Wound Healing Potential of Pharmaceutical Formulations (Gel and Paste) Prepared by Using Sea Water Snail

Abstract: Background: Marine species have long been valued as both nutritious foods for human diets and as a good source of medicinal chemicals. Purpose: The present work aimed to investigate wound healing potential of prepared gel and paste formulation. Materials and Methods: The work involved the preparation of extracts, preparation of formulation using extract and shells of Tibia curta sea water snail and determination of action against wound healing. Sea water snail extract was utilised to make Gels with varying compositions (G1-G9), and snail shells were used to make Paste (P1-P6). The gel and paste were evaluated based on different parameters. Results: The formulations with a neutral pH and excellent spreadability (G7 and P1) were chosen for further wound healing studies (since neutral pH does not cause irritancy and improved spreadability results in increased medication effectiveness). The extract, as well as both formulations, were used to treat excise wounds. Conclusion: The reduction in skin thickness reveals that formulations formulated using snail extract and shell were more efficient than simple snail extract. Keywords: Shell, Mollusca, Gel, Paste, Wound healing.

Formulation and Evaluation of Herbal Toothpaste against Biofilm Producing Staphylococcus aureus

Dental and oral hygiene is essential for overall health and well-being. Tooth brush and dental floss help remove food debris and plaque, while tooth paste and mouth wash are a key part of oral hygiene as they reduce bacterial growth. The use of chemical agents in tooth paste formulations are effective but can have undesirable side effects. The use of herbal extracts instead can be equally effective due to the presence of phytochemicals which render antibacterial and antiseptic properties, with no side effects. In this study we have formulated toothpaste using the extracts of orange peel, tomato peel and Eucalyptus leaves. The extracts were positive for phytochemicals like terpenoids, flavonoids and tannins. The formulated tooth paste demonstrated antibacterial and biofilm degrading activity against Staphylococcus aureus isolated from dental plaques. On comparison with commercially available toothpastes, the herbal formulation was observed to be more effective against the biofilm forming Staphylococcus aureus. Rakhi Bajpai3, Chitranshu Pandey4, Varaprasad Kolla*5

Innovations in Soldering Materials and Optimization of Solder Paste Printing and Inspection Parameters for System-in-Package Assembly

System-in-Package (SiP) assembly has become a popular solution for the challenges of continued miniaturization in the semiconductor industry. The continued and expected growth of the semiconductor industry in the coming years is driving more advanced assembly methods within System-in-Package and advanced packaging in general, and more advanced semiconductor assembly materials are required to meet those challenges such as solder paste specifically designed for SiP assembly, with fine solder powder and specifically formulated flux vehicles. Fine feature solder paste printing as an assembly method continues to be a challenge for SiP assembly. Small stencil aperture designs have necessitated fine-powder solder pastes, with type 5, type 6, and type 7 being common, as well as there being a need for type 8 for future, more advanced designs. Additionally, as more components are being packed into a SiP, solder paste rheology becomes an important characteristic to consider. Printing transfer efficiency, stencil life, and resistance to slump, are other important paste attributes to consider when evaluating solder paste for SiP assembly. While material properties are important to consider, proper equipment setup for a certain paste formulation is also necessary to maximize throughput and minimize assembly defects. The effects of solder paste printer parameters on fine-feature printing performance will be discussed, such as print speed, separation speed, separation distance, and stencil material. This paper will first focus on common failure modes in SiP assembly, and the technology advancements in both solder paste formulation and substrate design which help eliminate those failure modes. Then, this paper will discuss how proper stencil printer setup can reduce assembly defects, and will highlight designs-of-experiment outlining which stencil printer parameters are statistically significant in improving process yields of SiP assemblies with fine powder solder pastes, both with respect to pre-reflow inspection and post-reflow component placement. This paper will also discuss the importance of solder paste inspection with respect to assembly defects, and will highlight important parameters to optimize to accurately inspect solder paste deposits below 90 microns.

Multi-response mixture design applied for the formulation of a textile green camouflage ink with reproduction of a leaf green

This study establishes a proportioning model of green camouflage ink for textile screen printing to reproduce a leaf green using four high-performance inorganic pigment pastes: cobalt blue, chrome oxide green, chrome yellow, and iron red. In order to study the influence of four-color paste formulations on the camouflage performance of ink, a multi-response quadratic Scheffe mathematical model was established, and a total of 20 runs of color paste formulations were designed. Blending mixed color paste with water-based pure acrylic lotion, drying retarder, and thickener, the ink was then printed to the surface of the khaki camouflage decorative textile through screen printing. The spectral reflectance of the ink film was measured at 380∼1100 nm, and the response values were calculated. The regression model of each response was fitted using the least squares method. The model and verification experiments show that when the color paste formulation is 45.08% cobalt blue, 10.00% chrome green, 40.53% chrome yellow, and 4.39% iron red, the green camouflage ink match the leaf green well. The color difference between the green camouflage ink and the leaf green is less than 3, the reflectance ratio in the near-infrared and infrared bands is not less than 5, and the near-infrared brightness contrast with the leaf green is not more than 0.2. In addition, the green camouflage ink’s reflectivity is located in the leaf green hyperspectral channel.