Search Results (334)

The surface quality of biomedical implants, such as shoulder joint caps, plays a critical role in their performance, longevity, and biocompatibility. Most biomedical shoulder joints fail to reach their optimal functionality when finished through conventional techniques like grinding and lapping due to their inability to achieve nanometer-grade smoothness, which results in greater wear and friction along with potential failure. The advanced magnetorheological finishing (MRF) approach provides enhanced surface quality through specific dimensional control material removal. This research evaluates how MRF treatment affects the surface roughness performance and microhardness properties and wear resistance behavior of cobalt–chromium alloy shoulder joint caps which have biocompatible qualities. The study implements a magnetorheological finishing system built with an electromagnetic tool to achieve the surface roughness improvements from 0.35 µm to 0.03 µm. The microhardness measurements show that MRF applications lead to a rise from HV 510 to HV 560 which boosts the wear protection of samples. After MRF finishing, the coefficient of friction demonstrates a decrease from 0.12 to 0.06 which proves improved tribological properties of these implants. The results show that MRF technology delivers superior benefits for biomedical use as it extends implant life span and decreases medical complications leading to better patient health outcomes. The purposeful evaluation of finishing techniques and their effects on implant functionality demonstrates MRF is an advanced technology for upcoming orthopedic implants while yielding high precision and enhanced durability and functional output. Full article

This study analyzed the surface layer condition of X5CRNI18-10 stainless austenitic chromium–nickel steel test pieces after burnishing. Among the finishing operations, burnishing is an economical and low-environmental-impact process. In special cases, grinding can be replaced by burnishing, so the same roughness can be achieved with much lower environmental impact. The aim of this study is to analyze the roughness of a surface machined by diamond burnishing using Kraljic matrices. The technological parameters used during the burnishing tests were burnishing speed, feed rate, and burnishing force. The full factorial experimental design method was used to carry out the experiments. Using Kraljic matrices, the optimum burnishing force was determined to select the best value of the surface roughness, and the change in surface roughness was investigated using full factorial experimental design for different technological parameter combinations. A special improvement ratio formula was developed to evaluate the effectiveness of the burnishing process with respect to 2D and 3D roughness parameters. Full article

This study determines the influence of technological parameters of slide burnishing on the size of surface defects (scratches). The experiment was performed on ring-shaped samples of C45 steel. The samples had scratches made on their surface with a nominal depth from 10 μm to 70 μm. Slide burnishing was carried out using a variable force and feed. It was observed that regardless of the applied force and feed, scratches with a nominal depth of 10 μm and 20 μm were completely removed, and a “crushing” effect occurred. As for other surface defects, they were 2 to 27 times smaller compared to their values before burnishing. The surface roughness parameters Ra, Rt, Rpk, Rk, and Rvk decreased. Their values were 42% to 91% lower than those observed after grinding. The thickness of the strengthened layer ranged from 10 μm to 15 μm, and the degree of strengthening was from 20% to 38% at a depth of 1 μm. Compressive residual stresses occurred in the surface layer. Taking into account the surface layer properties and the effectiveness of surface defect removal, it should be noted that the most beneficial effects were obtained at F = 150 N and f = 0.03 mm/rev. Full article

In the domain of agricultural machinery, the utilization of carbon fiber-reinforced plastics (CFRP) for structural components, such as the chassis, facilitates substantial weight reduction. To integrate additional components, stainless-steel connection points can be bonded to the CFRP chassis using adhesives. This study investigates surface preparation methods to enhance adhesive bonding strength at the coupon level. Three adhesives (DP490, MA8110, SG300) were tested on untreated, sandblasted, and sandpaper-grinded steel surfaces. Contrary to predictions, the highest strength (28.7 MPa) for DP490 was achieved after simple acetone cleaning, despite lower surface roughness (Ra = 1.60 µm), while sandblasting (Ra = 3.71 µm, 22 MPa) and grinding (Ra = 2.78 µm, 25.95 MPa) performed worse due to incomplete adhesive penetration. Subsequent tests on DP490 with laser structuring (Ra = 88.8 µm) and sandblasting with coating (Ra = 1.94 µm) provided strengths of 27.5 MPa and 29.3 MPa, respectively. The findings indicate that, under the examined conditions, surface cleanliness plays a more critical role in adhesive bonding strength than surface roughness. Practically, acetone cleaning is a cost-effective and time-efficient alternative to treatments like sandblasting or laser structuring. This makes it attractive for industrial use in agricultural machinery. While this study focuses on coupon-level surfaces, the findings provide a basis for scaling to component-level applications in future research. Full article

The surface quality of diamond wire sawing (DWS) wafers directly affects the efficiency and yield of subsequent processing steps. This paper investigates the motion trajectory of abrasives in ultrasonic-assisted diamond wire sawing (UADWS) and its mechanism for improving surface quality. The influence of ultrasonic vibration on the cutting arc length, cutting depth, and interference of multi-abrasive trajectories was analyzed through the establishment of an abrasive motion trajectory model. The ultrasonic vibration transforms the abrasive trajectory from linear to sinusoidal, thereby increasing the cutting arc length while reducing the cutting depth. A lower wire speed was found to be more conducive to exploiting the advantages of ultrasonic vibration. Furthermore, the intersecting interference of multi-abrasive trajectories contributes to enhanced surface quality. Experimental studies were conducted on monocrystalline silicon (mono-Si) to verify the effectiveness of ultrasonic vibration in improving surface morphology and reducing wire marks during the sawing process. The experimental results demonstrate that, compared with DWS, UADWS achieves a significantly lower surface roughness Ra and generates micro-pits. The ultrasonic vibration induces a micro-grinding effect on both peaks and valleys of wire marks, effectively reducing their peak–valley (PV) height. This study provides a theoretical basis for optimizing UADWS process parameters and holds significant implications for improving surface quality in mono-Si wafer slicing. Full article

The 316L stainless steel material boasts exceptional corrosion resistance and plasticity, among other benefits, and finds extensive application in automotive components, molds, aerospace parts, biomedical equipment, and more. This work focuses on the surface polishing of selective laser melting (SLM) 316L stainless steel using 1064 nm nanosecond laser processing and mechanical grinding. The influence of laser processing parameters on the surface roughness of SLM-316L stainless steel was investigated using an orthogonal experiment. After laser processing, the surface roughness of SLM-316L stainless steel was reduced from 7.912 μm to 1.936 μm, but many randomly distributed irregular micro-cracks appeared on the surface. EDS and XRD detections illustrated that iron oxides were generated on the surface of SLM-316L stainless steel after laser processing. Mechanical grinding was further performed to achieve a nanometer surface finish and remove the metal oxides and micro-cracks generated on the surface of SLM-316L stainless steel after laser processing. The AFM measurement results indicate that the surface roughness of SLM-316L stainless steel was reduced to approximately 3 nm after mechanical grinding. Moreover, the micro-cracks and iron oxides on the surface of laser-processed SLM-316L stainless steel were completely removed. This work provides guidance for the precision polishing of SLM-316L stainless steel. Full article

Grinding, as the most crucial finishing process for bearing rings, influences the surface integrity of bearings through the roughness of the ground surface. In order to improve the surface roughness of bearing ring grinding under multiple working conditions, a prediction model of bearing ring surface roughness based on feature extraction was proposed. Firstly, the signal was decomposed using the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) algorithm, and the sensitive components were selected based on the correlation coefficient between Intrinsic Mode Functions (IMFs) and the original signal. The time-domain, frequency-domain, and entropy-domain features of the selected IMF components were extracted. Then, Principal Component Analysis (PCA) was employed for signal feature fusion, and a feature set was constructed in combination with grinding parameters. A prediction model based on Support Vector Regression (SVR) was established to achieve regression prediction of the grinding surface roughness. The proposed method for predicting the surface roughness of precision cylindrical grinding of bearings demonstrated that the determination coefficient (R²), mean absolute error (MAE), root mean square error (RMSE), and mean absolute percentage error (MAPE) were 0.9953, 0.0020, 0.0050, and 0.0187, respectively. The results indicate that the incorporation of entropy features and grinding parameters in the model provide more information pertinent to grinding surface roughness, thereby effectively enhancing the predictive accuracy. Full article

Single sapphire crystals has been widely used in technology such as light emitting diodes, lasers, high-temperature and high-voltage devices, special windows, and optical systems, and grinding is an important process of their machining. In order to reveal the influence of the grinding wheel speed, grinding depth, and feed rate on the ground surface quality of sapphire crystals, a three-factor and five-level orthogonal experiment was designed and completed. Variance and range analysis was conducted on the experimental results using the surface roughness Ra and subsurface crack damage depth (SSD) as evaluation indicators, and optimized parameter combinations were explored. Furthermore, mathematical prediction models for the power regression of the Ra and SSD were established based on the experimental data. The research results indicate that within the range of the process parameters used in this experiment, the grinding process did not achieve the full ductile removal of the material. Some of the material was removed in a brittle mode, forming fractured pits on the ground surface, and median crack propagation occurred in the subsurface, forming a subsurface microcrack damage layer. The influence of the grinding parameters on the Ra and SSD showed a consistent trend, which was that the parameter with the greatest impact was the grinding wheel speed, followed by the feed rate and grinding depth. The Ra and SSD obtained under the optimized grinding parameter combination were 0.326 μm and 2.86 μm, respectively. The research results provide an experimental basis and guidance for improving the surface quality of sapphire crystals during grinding. Full article

Hastelloy is widely used in the manufacturing of high-temperature components in the aerospace industry because of its high strength and corrosion-resistant physical properties, as well as its ability to maintain excellent mechanical properties at high temperatures. However, with developments in science and technology, the amount of available components for use in high-temperature and corrosive environments is increasing, their structures are becoming more complex and varied, and requirements with regard to the surface quality of the components has also become more stringent. The integration of cold plasma (CP) and nano-lubricant minimum quantity lubrication (NMQL), within a multi-physics coupling-assisted micro-grinding process (CPNMQL), presents a promising strategy to overcome this bottleneck. In this paper, micro-grinding of Hastelloy C-276 was performed under dry, CP, NMQL, and CPNMQL conditions, respectively. Contact angle testing, X-ray photoelectron spectroscopy (XPS) analysis, and nano-scratch experiments were used to investigate the mechanism of CPNMQL and to compare the micro-milling performance under different cooling and lubrication conditions employing various characteristics such as grinding temperature, surface roughness, and 3D surface profile. The results showed that at different micro-grinding depths, the micro-grinding temperature and surface roughness were significantly reduced under CP, NMQL, and CPNMQL conditions compared to dry friction. Among them, CPNMQL showed the best performance, with 53.4% and 54.7% reductions in temperature and surface roughness, respectively, compared to the dry condition. Full article

This paper presents an experimental study of uniform and variable texture patterns on a honed EN-GJS 400-15 spheroidal graphite cast iron surface. Textured samples were fabricated using a CNC electrochemical jet machining technique and tested against a 52100 G5 roller countersurface featuring a rectangular 1 mm × 13 mm contact area. Tribological tests were conducted in a fully flooded PAO4 lubricant bath at 30 °C on a TE-77 reciprocating sliding tribometer with a 25 mm stroke length. Frictional behaviour was assessed at test frequencies from 12 to 18 Hz under two loads, 11 N and 50 N, covering mixed and hydrodynamic lubrication regimes. Experimental results demonstrated that EJM textured surfaces were accurately fabricated within a ±2.50 µm standard error in depth, with chemical etching effects reducing the $R_q$ roughness of initial grinding marks by 0.223 µm. Textured surfaces exhibited a more pronounced friction performance at 50 N than at 11 N, exhibiting a consistent friction reduction of up to 18.8% compared to the untextured surface. The variable textured surface outperformed the uniform textured surface under the mixed lubrication regime due to the enhanced secondary lubrication effect. Optical and SEM analyses revealed that textured surfaces reduced plastic deformation and two-body abrasion. Full article

The optimal management of manufacturing processes can be achieved through a set of optimal decisions, which must be made to choose the best method to follow every time the process planner reaches a point when several potential manufacturing paths branch off. A dedicated method, namely the Holistic Optimization Method (HOM), has already been developed for this purpose and has been validated in several studies based on artificial- and real-instance databases. The HOM consists of two algorithms: (i) the causal identification of a manufacturing process and (ii) a comparative assessment with similar already-assessed manufacturing cases recorded in an instance database. The two algorithms can be used to estimate the values of the different performance indicators of manufacturing processes. Their application for processing cost estimation in the case of the manufacturing processes of bearing components has already shown good results. In this paper, the HOM is presented as a solution for predicting the timespan needed for grinding roller bearing rings. The specific algorithms of the HOM were applied, grounded in the use of a database with data collected from the industrial environment. The cause variables selected to describe the grinding process of the roller bearing rings were the inner and outer diameter of the ring, its width and weight, the machined surface roughness, the grinding stone rotation speed, the cutting speed, the feed rate, and the cutting depth, while the effect variable to be used by the process planner as the decision criterion was the timespan. Full article

In this paper, the wear characteristics of 20GrNi2MoV bearing steel under different working conditions were investigated by finite element simulation considering microscopic grain size and pin-on-disk friction experiments, and the wear mechanism during friction and wear was explained, along with a finite element model that took initial grain size and material organization into account to predict the process of subsurface crack initiation during friction. The results show that high-speed and large-load conditions have a significant effect on the wear characteristics of dry friction of pinned disks. The effect of high speed and load will greatly reduce the time of the grinding stage, and the friction coefficient can quickly reach a stable state; the roughness of the surface of the friction pair increases with the increase in load, but the roughness shows a tendency to first increase and then decrease with the increase in sliding speed. Martensitic phase transformation occurs in the friction subsurface, and the decrease in Mn element content is one of the causes of cracks on the subsurface of the material; with the increase in load and speed, the damage form of the sample disk material is changed from abrasive wear and adhesive wear to the mixture of three kinds of wear: abrasive wear, adhesive wear, and cracks. In addition, the simulation of crack initiation and growth agrees well with the experiment, which proves the accuracy of crack prediction. This study provides a reference for crack initiation prediction in the study of pinned disk friction vises. Full article

Purpose Maintaining the surface quality of ceramic restorations after clinical adjustments is critical for both aesthetic outcomes and long-term oral health, yet the optimal approach to restoring gloss and smoothness remains unclear. The purpose of this study is to investigate the effect of different surface finishing and grinding procedures on the surface gloss and roughness of three different monolithic lithium disilicate ceramics and one monolithic ultra-translucent zirconia ceramic. Materials and Methods A total of 104 specimens (1.5 × 12 × 14 mm) were prepared from four ceramic materials: LiSi CEREC Tessera (CT), GC Initial LiSi (LS), IPS e.max CAD (EC), and zirconia disc (KATANA UTML (KAT)). Each was divided into two subgroups based on surface finishing (mechanical polishing or glazing; n = 10). Gloss and surface roughness were measured using a glossmeter and a profilometer, respectively. One specimen per subgroup was analyzed under SEM at ×1000 magnification. Results Gloss and roughness values were analyzed with the two-way robust ANOVA test and multiple comparisons were made with Bonferroni correction. The significance level was set at p < 0.05. Mechanical polishing, glazing, and repolishing increased the gloss values of the materials, with the KAT group achieving the highest gloss in the repolishing groups. The lowest gloss values were observed in the grinding groups. Additionally, these surface treatments reduced the roughness of the surface of all the materials. Conclusions Surface finishing procedures significantly influenced the gloss and roughness of monolithic lithium disilicate and zirconia ceramics. Mechanical polishing systems performed similarly or better than glazing. However, selecting an appropriate polishing system for each material is essential. Full article

Surface roughness refers to the micron- or nanometer-scale irregularities (bumps and grooves) on material surfaces, and it varies greatly as particles are refined, affecting their flotation behavior, wettability, and bubble–particle interactions. In this paper, the main roughening and measurement methods for surface roughness are summarized, the effects of surface roughness on flotation behavior and wettability are reviewed, and the main wettability models for rough surfaces are also introduced. Grinding is the most commonly used method, while other methods, such as acid etching, abrasion, sand-blasting, ultrasonic pretreatments, and microwave treatments, have also been explored. Most research shows that increasing the surface roughness effectively enhances the hydrophobicity of hydrophobic surfaces and the hydrophilicity of hydrophilic surfaces. This improvement leads to better flotation recovery and kinetics for hydrophobic surfaces, whereas it deteriorates that for hydrophilic surfaces. Moreover, the relationship between surface roughness and bubble–particle interactions, including bubble–particle attachment, interaction energy, and interaction force, is introduced. Most research shows that increased surface roughness effectively decreases the attachment time and energy barrier and increases the adhesion force between air bubbles and rough hydrophobic surfaces. Conversely, these effects can be detrimental to rough hydrophilic surfaces. This paper also addresses existing problems and challenges in the field and offers references and suggestions for future research efforts. Full article

This study assessed the repair shear bond strength (SBS; MPa) and surface roughness (Ra; μm) of aged hybrid ceramic (Cerasmart270, GC) and nano-hybrid ceramic (Grandio Blocs, Voco) CAD/CAM blocks after different surface pretreatment methods. In this study, 2 mm thick Cerasmart270 and Grandio Blocs were cut into slabs (Isomet; n = 80 per group). Following aging for six months, the specimens in each CAD/CAM material were randomly divided into four groups (n: 20 each) according to the surface pretreatments: control (no pretreatment), Er:YAG laser, sandblasting, and bur grinding. A total of 10 specimens in each CAD/CAM material pretreatment group were used for Ra evaluation (Perthometer Mahr), while the other 10 were for SBS. After the application of a silane primer (G-Multi Primer, GC) and universal adhesive (G2-Bond, GC), composite build-ups (Filtek Z250; 3MESPE) were performed for the SBS evaluation. After storage in distilled water for 24 h, SBS was evaluated with a universal testing machine (Instron). SBS and Ra data were analyzed with two-way ANOVA and Tukey’s post hoc tests (p < 0.05). SBS was significantly affected by the surface pretreatment methods (p = 0.0001) and by the types of CAD/CAM material (p = 0.005). Bur grinding showed the highest SBS for both CAD/CAM materials, while the control groups yielded significantly lower SBS than bur grinding and sandblasting (p < 0.05). Er:YAG lasers did not significantly enhance the SBS compared to the control group. Sandblasting presented significantly higher SBS than lasers only in Grandio Blocs (p < 0.05). The surface pretreatment methods significantly influenced Ra (p = 0.0001); however, no significant interaction was found between the types of CAD/CAM material and the surface pretreatments (p > 0.05). Control groups exhibited, significantly, the lowest Ra for both materials (p = 0.0001), while no significant differences were observed between the other pretreatment methods. Bur grinding was identified as the most effective pretreatment method for repairing hybrid ceramic CAD/CAM materials. Full article