Preparation and performances of coated and aluminous entry boards with water-soluble resins for PCB drilling

Circuit World ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 153-161 ◽  
Author(s):  
Hu Zhou ◽  
Bin Yu ◽  
Ning Li ◽  
Jie Zhou ◽  
Xiaoyang Luo ◽  
...  
Keyword(s):  
Production Efficiency ◽  
Heat Dissipation ◽  
Water Solubility ◽  
Water Soluble ◽  
Circuit Board ◽  
Drilling Process ◽  
Drill Bit ◽  
Scanning Calorimetry ◽  
Location Accuracy ◽  
Content Type

Purpose This paper aims to provide a new drilling entry board for printed circuit board (PCB) process, superior in heat dissipation, lubrication, water solubility and hole location accuracy, achieving an excellent drilling process. Design/methodology/approach Using a mixture of polyethylene glycol (PEG) and water-soluble adhesives as hydrosoluble, endothermic and lubricant resins and aluminum foils as baseplates, a series of coated and aluminous entry boards (CABs) for PCB drilling was successfully prepared. The surface appearance of the entry boards was observed clearly by scanning electron microscopy (SEM). The endothermic and lubricant effects of the resins applied on the CABs was characterized by differential scanning calorimetry (DSC) and their water solubility was tested in the normal-temperature water (25°C). Moreover, the CABs’ good drilling properties were tested when they were used for PCB drilling. Findings The SEM analysis showed that the surfaces of the resin layers coated on the CABs whose coating thicknesses were less than 80 μm were smoother and flatter, which could improve hole location accuracy and reduce drill breakage ratio. By virtue of DSC, the endothermic and lubricant effects of the CABs were proven. The fusion of PEG in the resin layers could absorb the heat produced by drilling, restrain the temperature of the drill bit and hole rising and lubricate the drill bit efficiently when a hole was being drilled, which could achieve high-quality holes with good production efficiency. The water-soluble test showed that the prepared CABs had excellent water solubility at normal temperature, enabling the resin left on the hole walls and in the flute of the drill bit to be washed away easily and thereby improving the drilling efficiency and quality. The drilling tests showed that the increase in the thickness of the CABs’ coating could improve the hole location accuracy and alleviate the bit wear. In addition, the suitable coating thickness could ensure the firm adhering of the resin coating the aluminum foil, effectively avoid drill intertwist and prevent the resin debris from blocking the drilled holes on the surface of the entry board, which could hinder chip removal, resulting in poor hole wall quality and drill breakage. Originality/value This paper has a remarkably high industrial practicality in the PCB manufacture process.

Characterization of drill bit breakage in PCB drilling process based on high-speed video analysis

Circuit World ◽  
2017 ◽  
Vol 43 (3) ◽  
pp. 89-96 ◽  
Author(s):  
Hongyan Shi ◽  
Xiaoke Lin ◽  
Yun Wang
Keyword(s):  
Video Analysis ◽  
High Speed ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Drilling Process ◽  
Drill Bit ◽  
Content Type ◽  
High Speed Video ◽  
Micro Drill

Purpose The purposes of this paper are to study the characterization of drill bit breakage in printed circuit board (PCB) drilling process based on high-speed video analysis and to provide an important reference for micro drill bit breakage prediction. Design/methodology/approach Based on PCB drilling experiment, the high-speed camera was used to observe the micro drill breakage process and the chip removal process. The variation of chip in the drilling process was studied and one of the key reasons for the drill bit breakage was analysed. Finally, the swing angles’ feature during the breakage process of the micro drill was analysed and researched with the image processing tools of MATLAB. Findings The micro drill was prone to breakage mainly because of the blocked chips. The breakage process of the micro drill can be divided into the stage of stable chips evacuation, the stage of blocked chips and the stage of drill bit breakage. The radians of swing angles were basically in the range of ±0.01 when the drilling possess is normal. But when the radians of swing angles considerably exceeded the range of ±0.01, the micro drill bit may be fractured. Originality/value This paper presented the method to study the characterization of drill bit breakage in the PCB drilling process by using high-speed video analysis technology. Meanwhile, an effective suggestion about monitoring the radians of swing angles to predict the breakage of micro drill bit was also provided.

The entry drilling process of flexible printed circuit board and its influence on hole quality

Circuit World ◽  
2015 ◽  
Vol 41 (4) ◽  
pp. 147-153 ◽  
Author(s):  
Lijuan Zheng ◽  
Chengyong Wang ◽  
Xin Zhang ◽  
Yuexian Song ◽  
Lunqiang Zhang ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Drilling Process ◽  
Hole Quality ◽  
Location Accuracy ◽  
Content Type ◽  
Printed Circuit ◽  
Flexible Printed Circuit ◽  
Micro Drilling ◽  
Micro Hole

Purpose – The purpose of this study is to present the entry drilling process of flexible printed circuit board (FPCs) and its influence on hole quality, especially hole location accuracy. Compared with the traditional PCB drilling process, the technology of drilling FPCs is facing more problems, such as hole location accuracy, smear on the hole wall surface, burned hole wall surface, etc. Moreover, the materials of FPCs are quite different from the rigid printed circuit boards (RPCs). FPCs no longer contain glass fiber cloths to reinforce resin, resulting in flexibility. Micro-hole quality is the most important issue in FPC drilling. Suggestions were given to obtain higher hole qualities and higher FPC reliability. Design/methodology/approach – The entry drilling process of FPC with different kind of entry boards was observed by a high-speed camera. The hole qualities of FPC micro-drilling, especially hole location accuracy and hole entrance quality, were measured. The relationship between entry boards and hole quality was analyzed. Findings – Significant sliding occurred when drilling FPC with using no-entry board or pure aluminum plate entry board. On the contrary, no significant sliding occurred when using LC-110 or resin-coated aluminum foil (MVC) entry boards. The type, thickness and use-pattern of entry boards influenced hole location accuracy of FPCs seriously. In addition, entry board also influenced the micro-hole entrance quality and micro-hole diameter. The entrance quality of drilling FPC with LC-110 entry board was the best. The diameter variation of drilling FPC with MVC entry board was the smallest. The hole location accuracy decreased as the thickness of entry board increased. Thus, the best use-pattern of entry board was putting a LC-110 under MVC entry board, resulting in best entrance quality and hole location accuracy. Originality/value – The technology and manufacturing of FPCs in China are obviously behind. Research of FPCs micro-drilling and research data are lacking so far. Thus, it is most necessary to improve the technology level of FPCs micro-drilling in China. Researches on hole quality, especially hole location accuracy of FPCs drilling, were performed in this paper. Suggestions were given to obtain higher hole quality of FPCs.

Experimental study on micro-drills wear during high speed of drilling IC substrate

Circuit World ◽  
2014 ◽  
Vol 40 (2) ◽  
pp. 61-70 ◽  
Author(s):  
Linfang Wang ◽  
Lijuan Zheng ◽  
Cheng yong Wang ◽  
Shan Li ◽  
Yuexian Song ◽  
...  
Keyword(s):  
High Speed ◽  
Base Material ◽  
Circuit Board ◽  
Drilling Process ◽  
Wall Roughness ◽  
Location Accuracy ◽  
Content Type ◽  
Drill Diameter ◽  
Micro Holes ◽  
Micro Drill

Purpose – Compared with the traditional printed circuit board (PCB) drilling process, the technology of drilling IC substrate is facing more problems, such as much smaller hole diameter, more intensive hole space, thinner sheet and more complicated materials are drilled in process. Moreover, the base material of IC substrate is different from traditional PCB, more kinds of fillers added in IC substrate which make the drill worn seriously during drilling process. Micro-drills wear and micro holes quality are the most important questions when drilling IC substrate so far. Wear morphology of micro-drill, holes wall roughness and hole location accuracy are researched in this paper. The influence factors of micro-drills wear and micro holes quality are also studied in this drilling process. The paper aims to discuss these issues. Design/methodology/approach – Two drills with same structure and different diameter are used to drill different stacks of IC substrate and drill different holes in this paper. There are four experiments made and the drilling parameters including spindle speed (n), feed rate (vf) and retraction speed (vr) are recommended by drill manufacturing company. Wear morphologies of drill are observed, holes wall roughness (Rmax) and holes location accuracy (Cpk) are measured in this paper. Analyzing the main factors influence on drill wear, holes wall roughness and holes location accuracy through these experiments. Findings – The micro-drills of IC substrate wear more severely compared with other material of PCB through the experimental results in this paper. Drill diameter has influence on micro-drill wear when drilling IC substrate, the smaller of drill is, the more severely of micro-drill wears. Drill diameter affect the holes wall roughness too, the holes wall roughness of larger holes is better than smaller one in a certain range. The drilled holes number also has influence on micro-drills wear, holes wall roughness and holes location accuracy. The more drilled holes, the seriously of micro-drills wear, and the worn drill would destroy the hole quality. Therefore, the more drilled holes lead the bad holes wall roughness and holes location accuracy in this paper. In addition, stacks of IC substrate affect much on the holes location accuracy, the more stacks, the worse holes location accuracy. Originality/value – Chinese Mainland is obviously lagging behind in technology and manufacturer of IC substrate which is incompatible with the nation circumstances. There is few research of drilling IC substrate in China and research data are lacking so far. It is most necessary to improve the technology level of drilling IC substrate in China. In order to reduce the wear of micro-drills and improve the quality of micro-holes, many experimental tests about drilling IC substrate are researched in this paper.

scholarly journals Effect of DMPA and Molecular Weight of Polyethylene Glycol on Water-Soluble Polyurethane

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1915 ◽  
Author(s):  
Eyob Wondu ◽  
Hyun Woo Oh ◽  
Jooheon Kim
Keyword(s):  
Molecular Weight ◽  
Contact Angle ◽  
Polyethylene Glycol ◽  
Photoelectron Spectroscopy ◽  
Water Solubility ◽  
Soft Segment ◽  
Water Soluble ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

scholarly journals Enhanced Water Solubility and Oral Bioavailability of Paclitaxel Crystal Powders through an Innovative Antisolvent Precipitation Process: Antisolvent Crystallization Using Ionic Liquids as Solvent

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1008 ◽  
Author(s):  
Qilei Yang ◽  
Chang Zu ◽  
Wengang Li ◽  
Weiwei Wu ◽  
Yunlong Ge ◽  
...  
Keyword(s):  
Oral Bioavailability ◽  
High Performance ◽  
Water Solubility ◽  
Water Soluble ◽  
Precipitation Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Antisolvent Precipitation ◽  
Antisolvent Crystallization ◽  
Artificial Gastric Juice

Paclitaxel (PTX) is a poor water-soluble antineoplastic drug with significant antitumor activity. However, its low bioavailability is a major obstacle for its biomedical applications. Thus, this experiment is designed to prepare PTX crystal powders through an antisolvent precipitation process using 1-hexyl-3-methylimidazolium bromide (HMImBr) as solvent and water as an antisolvent. The factors influencing saturation solubility of PTX crystal powders in water in water were optimized using a single-factor design. The optimum conditions for the antisolvent precipitation process were as follows: 50 mg/mL concentration of the PTX solution, 25 °C temperature, and 1:7 solvent-to-antisolvent ratio. The PTX crystal powders were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, high-performance liquid chromatography–mass spectrometry, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Raman spectroscopy, solid-state nuclear magnetic resonance, and dissolution and oral bioavailability studies. Results showed that the chemical structure of PTX crystal powders were unchanged; however, precipitation of the crystalline structure changed. The dissolution test showed that the dissolution rate and solubility of PTX crystal powders were nearly 3.21-folds higher compared to raw PTX in water, and 1.27 times higher in artificial gastric juice. Meanwhile, the bioavailability of PTX crystal increased 10.88 times than raw PTX. These results suggested that PTX crystal powders might have potential value to become a new oral PTX formulation with high bioavailability.

Evaluation of new technologies and materials for printed circuit boards with improved heat dissipation properties

Circuit World ◽  
2016 ◽  
Vol 42 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Michal Baszynski ◽  
Edward Ramotowski ◽  
Dariusz Ostaszewski ◽  
Tomasz Klej ◽  
Mariusz Wojcik ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Printed Circuit Boards ◽  
Heat Dissipation ◽  
Printed Circuit Board ◽  
New Technologies ◽  
Electronic Device ◽  
Circuit Board ◽  
New Materials ◽  
Content Type ◽  
Printed Circuit

Purpose – The purpose of this paper is to evaluate thermal properties of printed circuit board (PCB) made with use of new materials and technologies. Design/methodology/approach – Four PCBs with the same layout but made with use of different materials and technologies have been investigated using thermal camera to compare their thermal properties. Findings – The results show how important the thermal properties of PCBs are for providing effective heat dissipation, and how a simple alteration to the design can help to improve the thermal performance of electronic device. Proper layout, new materials and technologies of PCB manufacturing can significantly reduce the temperature of electronic components resulting in higher reliability of electronic and power electronic devices. Originality/value – This paper shows the advantages of new technologies and materials in PCB thermal management.

Formulation and Evaluation of Benidipine Nanosuspension

2021 ◽  
pp. 4111-4116
Author(s):  
Sejal Patel ◽  
Anita P. Patel
Keyword(s):  
Particle Size ◽  
Water Solubility ◽  
Polymer Concentration ◽  
Oral Route ◽  
Water Soluble ◽  
In Vitro Dissolution ◽  
Scanning Calorimetry ◽  
23 Factorial Design ◽  
Selection Of

In the interest of administration of dosage form oral route is most desirable and preferred method. After oral administration to get maximum therapeutic effect, major challenge is their water solubility. Water insoluble drug indicate insufficient bioavailability as well dissolution resulting in fluctuating plasma level. Benidipine (BND) is poorly water soluble antihypertensive drug has lower bioavailability. To improve bioavailability of Benidipine HCL, BND nanosuspension was formulated using media milling technique. HPMC E5 was used to stabilize nanosuspension. The effect of different important process parameters e.g. selection of polymer concentration X1(1.25 mg), stirring time X2 (800 rpm), selection of zirconium beads size X3 (0.4mm) were investigated by 23 factorial design to accomplish desired particle size and saturation solubility. The optimized batch had 408 nm particle size Y1, and showed in-vitro dissolution Y2 95±0.26 % in 30 mins and Zeta potential was -19.6. Differential scanning calorimetry (DSC) and FT-IR analysis was done to confirm there was no interaction between drug and polymer.

Development and Characterization of the Neuroregenerative Xanthohumol C/Hydroxypropyl-β-cyclodextrin Complex Suitable for Parenteral Administration

Planta Medica ◽  
2019 ◽  
Vol 85 (16) ◽  
pp. 1233-1241
Author(s):  
Michael Kirchinger ◽  
Lara Bieler ◽  
Julia Tevini ◽  
Michael Vogl ◽  
Elisabeth Haschke-Becher ◽  
...  
Keyword(s):  
Water Solubility ◽  
Pharmaceutical Research ◽  
Water Soluble ◽  
Complexing Agents ◽  
Cyclodextrin Complex ◽  
Scanning Calorimetry ◽  
In Vivo Experiments ◽  
Strong Candidate

AbstractThe chroman-like chalcone Xanthohumol C, originally found in hops, was demonstrated to be a potent neuroregenerative and neuroprotective natural product and therefore constitutes a strong candidate for further pharmaceutical research. The bottleneck for in vivo experiments is the low water solubility of this chalcone. Consequently, we developed and validated a suitable formulation enabling in vivo administration. Cyclodextrins were used as water-soluble and nontoxic complexing agents, and the complex of Xanthohumol C and 2-hydroxypropyl-β-cyclodextrin was characterized using HPLC, HPLC-MS, NMR, and differential scanning calorimetry. The water solubility of Xanthohumol C increases with increasing concentrations of cyclodextrin. Using 50 mM 2-hydroxypropyl-β-cyclodextrin, solubility was increased 650-fold. Furthermore, in vitro bioactivity of Xanthohumol C in free and complexed form did not significantly differ, suggesting the release of Xanthohumol C from 2-hydroxypropyl-β-cyclodextrin. Finally, a small-scaled in vivo experiment in a rat model showed that after i. p. administration of the complex, Xanthohumol C can be detected in serum, the brain, and the cerebrospinal fluid at 1 and 6 h post-administration. Mean (± SD) Xanthohumol C serum concentrations after 1, 6, and 12 h were determined as 463.5 (± 120.9), 61.9 (± 13.4), and 9.3 (± 0.8) ng/mL upon i. v., and 294.3 (± 22.4), 45.5 (± 0.7), and 13 (± 1.0) ng/mL after i. p. application, respectively. Accordingly, the formulation of Xanthohumol C/2-hydroxypropyl-β-cyclodextrin is suitable for further in vivo experiments and further pharmaceutical research aiming for the determination of its neuroregenerative potential in animal disease models.

scholarly journals SPRAY DRYING APPROACH IN PREPARATION AND CHARACTERIZATION OF SOLID DISPERSION OF EPROSARTAN MESYLATE

2021 ◽  
Vol 10 (3) ◽  
pp. 2929-2932
Author(s):  
Sachin N Kothawade
Keyword(s):  
Spray Drying ◽  
Solid Dispersion ◽  
Water Solubility ◽  
Solid Dispersions ◽  
Weight Ratio ◽  
Water Soluble ◽  
Drying Methods ◽  
Scanning Calorimetry ◽  
Dispersion Systems ◽  
Physicochemical Features

Spray drying methods were used to make solid dispersions of the medication Eprosartan Mesylate, which is poorly water-soluble. X-ray Powder diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry were used to characterize the products' physicochemical features as well as drug-polymer interactions. Eprosartan Mesylate was shown to be dispersed amorphously in both solid dispersion systems, with a drug to polymer weight ratio of 1:4.The drug and polymer created hydrogen bonds, according to the spectrum data. Both techniques utilized in this investigation enhanced Eprosartan Mesylate solubility. Solid dispersions, on the other hand, performed significantly better, dissolving completely in 5 minutes and at a rate that was about 20 times faster than API within the first 15 minutes. Spray drying is a good way to boost the bioavailability of drugs that are poor water solubility.

scholarly journals Mechanisms of Antibacterial Action of Three Monoterpenes

2005 ◽  
Vol 49 (6) ◽  
pp. 2474-2478 ◽  
Author(s):  
Domenico Trombetta ◽  
Francesco Castelli ◽  
Maria Grazia Sarpietro ◽  
Vincenza Venuti ◽  
Mariateresa Cristani ◽  
...  
Keyword(s):  
Water Solubility ◽  
Lipid Fraction ◽  
Antimicrobial Effect ◽  
Physicochemical Characteristics ◽  
Water Soluble ◽  
Negative Bacterium ◽  
Positive Bacterium ◽  
Linalyl Acetate ◽  
Scanning Calorimetry ◽  
Fluorescent Marker

ABSTRACT In the present paper, we report the antimicrobial efficacy of three monoterpenes [linalyl acetate, (+)menthol, and thymol] against the gram-positive bacterium Staphylococcus aureus and the gram-negative bacterium Escherichia coli. For a better understanding of their mechanisms of action, the capability of these three monoterpenes to damage biomembranes was evaluated by monitoring the release, following exposure to the compounds under study, of the water-soluble fluorescent marker carboxyfluorescein from unilamellar vesicles with different lipidic compositions (phosphatidylcholine, phosphatidylcholine/phosphatidylserine [9:1], phosphatidylcholine/stearylamine [9:1], and phosphatidylglycerol/cardiolipin [9:1]). Furthermore, the interaction of the terpenes tested with dimyristoylphosphatidylcholine multilamellar vesicles as model membranes was monitored by means of differential scanning calorimetry. Finally, the results were related to the relative lipophilicity and water solubility of the compounds examined. Taken together, our findings lead us to speculate that the antimicrobial effect of (+)menthol, thymol, and linalyl acetate may result, at least partially, from a perturbation of the lipid fraction of microorganism plasma membrane, resulting in alterations of membrane permeability and in leakage of intracellular materials. Besides being related to physicochemical characteristics of the drugs (such as lipophilicity and water solubility), this effect seems to be dependent on lipid composition and net surface charge of microbial membranes. Furthermore, the drugs might cross the cell membranes, penetrating into the interior of the cell and interacting with intracellular sites critical for antibacterial activity.

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