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In view of the problems of inaccurate sandblasting depth control, large operating vibration, clamping instability, and poor process consistency in the surface treatment of the runner of valve body casting, a new type of runner sandblasting gun was designed. The sandblasting gun integrates depth adjustable and active clamping functions, an adjustable fixing sleeve based on the principle of cone thread compound locking, a barrel with an axial scale and a wide-face clamping mechanism driven by a two-way thread, which realizes the accurate setting of the blasting depth and the fast and rigid connection between the spray gun valve body, improves the stability, repeatability and convenience of operation of the sandblasting operation, and meets the technical requirements of high-precision valve body casting runner surface treatment.

Surface coatings may experience wear, peeling, and other forms of damage during service, which severely impacts their absorbing performance. To restore the performance of damaged coatings, it is crucial to remove coatings. This paper investigated the effect of sandblasting angle on the removal of damaged coatings from TC4 titanium alloy surfaces and determined the optimal sandblasting angle. When SiC is selected as the abrasive, the removal effect is best when the blasting angle is 60°, taking into account the comprehensive sandblasting effect and the degree of damage to the substrate. The sandblasting removal mechanism of surface coatings was explored and this study provides a procedural pathway for the effective removal of surface coatings.

Investment castings often have surface impurities, and pieces of shell moulds can remain on the surface after sandblasting. Identification of defects involves time-consuming manual inspections in working environments of high noise and poor air quality. To reduce labour costs and increase the health and safety of employees, automated optical inspection (AOI) combined with a deep learning framework based on convolutional neural networks (CNNs) was applied for the detection of sandblasting defects. Four classic CNN models, including AlexNet, VGG-16, GoogLeNet, and ResNet-34, were applied for training and predictive classification. A comprehensive comparison reveals that AlexNet, VGG-16, and GoogLeNet v1 could accurately determine whether there were defects. Among the four models, AlexNet and VGG-16 were the most accurate, with prediction accuracy of 99.53% and 99.07% for qualifying products and both 100% for defective products. GoogLeNet v4 and ResNet-34 did not perform as expected in defect prediction. The reasoning behind the poor performance of GoogLeNet v4 and ResNet-34 is attributed to the restrictedness of the investment casting dataset to use models with residual learning architectures. Finally, a direct detection technique based on the AOI and CNN structure with a fast and flexible computational interface was demonstrated.

In dentistry, the surfaces of titanium implants are often sandblasted and acid-etched in order to support successful osseointegration. The aim of this study was to investigate the impact of various sandblasting parameters on the surface roughness, contact angle and surface energy of additively manufactured (TiAl6V4) and machined commercially pure titanium (cpTi) surfaces. A total of 56 disc-shaped samples were produced using either laser powder bed fusion (TiAl6V4) or using precision cutting (cpTi). The samples were then sandblasted with different angles, distances, and pressures using an automated sandblasting machine. Afterwards, surface roughness and contact angle for water and diiodomethane were measured, and scanning electron microscopy images were taken. The results showed that the initially rough TiAl6V4 samples became smoother after sandblasting, while the smooth cpTi surfaces became rougher. Sandblasting pressure had the most significant influence on surface roughness. The surface energy of sandblasted TiAl6V4 samples showed no significant change compared to the as-built state (26.6±1.3 to 26.3±1.8 mJ/m ). In contrast, cpTi samples showed a reduction in surface energy after sandblasting (32.3±1.6 to 26.8±1.2 mJ/m ). Scanning electron microscopy revealed irregular surfaces with grooves and ridges for both types of samples. The roughness of TiAl6V4 decreased at higher sandblasting pressures, whereas cpTi surfaces became rougher. Surface roughness after sandblasting is strongly influenced by the initial surface, which differs in additively manufactured TiAl6V4 samples compared to machined cpTi surfaces.

To investigate the effect of different sandblasting settings on the shear bond strength (SBS) in the repair of resin composite, specimens (resin composite, enamel, and dentin; each group n = 16) were sandblasted by varying the parameters of air pressure (0.2/0.3/0.4 MPa), angle (45/90°), particle size (27/50 μm), tip size (0.8/1.2 mm), and distance (2/5/10 mm) prior to the application of a universal adhesive (Adhese Universal) and resin composite (adhesive area: 7.07 mm2). The specimens were subjected to artificial aging (10,000 cycles, 5–55 °C) prior to (resin composite only) and after repair. Groups without mechanical pretreatment and resin composite incremental bond strength served as controls. Statistical analysis was performed using ANOVAs, post hoc tests, and Chi2-tests (p < 0.05). Only air pressure and distance impacted SBS (p ≤ 0.049). However, resin composite SBS did not differ from the resin composite incremental SBS within all sandblasting settings (positive control: 21.0 ± 5.0 MPa, p ≥ 0.566). While sandblasting did not impact bond strength on enamel (control: 20.5 ± 5.1 MPa, p ≥ 0.999), most settings resulted in a lower bond strength on dentin (control: 20.1 ± 4.7 MPa, p ≤ 0.027). In conclusion, sandblasting significantly improves resin composite repair bond strength, while application parameters are of minor relevance.

In the automotive and aerospace industry, abrasive products lodge the major portion of the machining applications. Among that, the coated abrasive disc is used for a finishing application. Once the disc is fully consumed, the disc is unused and considered waste. The present work focuses on removing phenol-formaldehyde resin coating, and the fiber backing is reused for the same coated abrasive disc production application as flexible fiber backing. A sandblasting technique removes phenol-formaldehyde resin coating and embedded abrasive grains. During the fiber backing recovery process, the experimental parameters such as abrasive pressure, abrasive type, abrasive size, and orientation of the disc are varied to find out the optimal surface roughness value for reusing the produced coated abrasive discs. The results highlight that the recovered backing has an abrasive size of 120 mesh pressure of 0.20 MPa, an abrasive type of garnet, and a standoff distance of 1 mm. Surface features such as surface roughness and micrographs of the eroded surface are analyzed. Finally, the recovered backing was reused in the coated abrasive disc production, and the performance of the recovered disc was compared with the standard discs. The recovered fiber backing disc product was similar to a standard fresh disc.

Thermal barrier coatings (TBCs) are widely used to protect high-temperature components against harsh environments, such as extremely high temperatures. In this work, a second generation Ni-based single crystal superalloy (DD6) was treated in two ways: (1) via simple surface sandblasting under different pressures with no additional coating, and (2) through simple surface sandblasting under different pressures and then by applying NiCoCrAlYHf (HY5) coatings. The effects of pre-treatment (sandblasting) and the HY5 coating on the surface recrystallization of the alloy were thoroughly investigated. According to the results, both sandblasting pressure and the presence or absence of a coating significantly influence surface recrystallization. In particular, the critical sandblasting pressure for recrystallization increased the maximum recrystallization depth in both the coated and uncoated samples. Meanwhile, the recrystallization depth of the alloy with a coating was reduced compared to that without a coating. In addition, the number of recrystallized cells in the coated alloy was decreased, which indicated that the HY5 coating effectively reduced the degree of recrystallization.

Dentine pretreatment through sandblasting procedures has been widely studied but no curve test results are currently available. Thus, the aim herein was to in vitro compare the adhesive strength in sandblasted or not samples using a universal testing machine. Thirty -two bovine teeth were divided into two groups, namely test (n = 16 bars), sandblasting with aluminum oxide particles (50 µm) was performed before the adhesion procedures), and control (n = 16 bars), where no sandblasting procedure was performed. A bi-material curve test was used to evaluate the characteristics of the dentine pretreatment in terms of tensile stress and fracture strength. A scanning electron microscope (SEM) was used to analyze the fracture topography in the composite, bonding, dentin, and at the relative interfaces. The results demonstrated a statistically significant difference between the two groups in terms of tensile stress at maximum load showing values of 84.300 ± 51.342 MPa and 35.071 ± 16.609 MPa, respectively for test and control groups (p = 0.033). Moreover, a fracture strength test showed values of 18.543 ± 8.145 MPa for test and 8.186 ± 2.833 MPa for control group (p = 0.008). In conclusion, the sandblasting treatment of the dentine significantly influenced the mechanical resistance of the adhesion in this in vitro study.

In the actual production of ultrasonic atomization, to cater to the consumers’ preference for the appearance of the products, the surface of the ultrasonic atomizer needs to be treated with different machining processes, which tend to affect the surface hardness of the atomizer, and affect the atomization performance of the atomizer. Therefore, the beauty of the appearance and the reduction of atomization performance has become a contradiction in the current industrial production of atomizers. In this study, it is theoretically proved that the hardness is inversely proportional to the atomization rate. Two machining processes are selected among the five common processing techniques for the experiment: (1) mirror polishing treatment of the atomizer, and (2) mirror polishing-sandblasting-plasma spraying treatment of the atomizer. To evaluate various aspects of the atomizer’s performance, several experiments were conducted, focusing on the hardness of the atomizer’s surface, its vibration displacement and the atomization performance. The results indicate that there is an inverse relationship between the atomization rate and the surface hardness, while the atomization rate is directly proportional to the peak vibration displacement. These findings align with the theoretical predictions. Following the process (2) treatment, the atomizer’s surface developed a frosted texture. As a result, its hardness increased by approximately 13.6%, the peak vibration displacement decreased by around 23.46%, and the atomization rate dropped by about 30.59% compared to the untreated atomizer. After the treatment of process (1), the surface of the atomizer had a mirror texture, where the hardness decreased by around 26.8%, the peak vibration displacement increased by approximately 64.2%, and the atomization rate increased by approximately 110.81%, compared with the untreated atomizer. The hardness influences the atomization rate by affecting the vibration displacement of the ultrasonic atomizer.

This study investigates the effect of defined working distances between the tip of a sandblasting device and a resin composite surface on the composite–composite repair bond strength. Resin composite specimens (Ceram.x Spectra ST (HV); Dentsply Sirona, Konstanz, Germany) were aged by thermal cycling (5000 cycles, 5–55 °C) and one week of water storage. Mechanical surface conditioning of the substrate surfaces was performed by sandblasting with aluminum oxide particles (50 µm, 3 bar, 10 s) from varying working distances of 1, 5, 10, and 15 mm. Specimens were then silanized and restored by application of an adhesive system and repair composite material (Ceram.x Spectra ST (HV)). In the negative control group, no mechanical surface pretreatment or silanization was performed. Directly applied inherent increments served as the positive control group (n = 8). After thermal cycling of all groups, microtensile repair bond strength was assessed, and surfaces were additionally characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The negative control group reached the significantly lowest microtensile bond strength of all groups. No significant differences in repair bond strength were observed within the groups with varying sandblasting distances. Composite surfaces sandblasted from a distance of 1 mm or 5 mm showed no difference in repair bond strength compared to the positive control group, whereas distances of 10 or 15 mm revealed significantly higher repair bond strengths than the inherent incremental bond strength (positive control group). In conclusion, all sandblasted test groups achieved similar or higher repair bond strength than the inherent incremental bond strength, indicating that irrespective of the employed working distance between the sandblasting device and the composite substrate surface, repair restorations can be successfully performed.