Evaluation Of Wear Research Articles

An adaptive method of measuring the rake face wear of end mills based on image feature point set registration

An acceptable tool wear evaluation and acquisition approach is critical for developing an accurate, rapid, and practical online tool wear prediction system. The one-dimensional crater wear depth is difficult to quantify, and relying solely on flank wear width is very simplistic. External conditions such as vibration and illumination have a large impact on two-dimensional wear area and three-dimensional volume. In practice, these are difficult to successfully characterize tool wear. This work proposes a two-dimensional rake face edge loss area as an additional indicator to assess milling cutter wear. An adaptive measurement approach based on 2D image feature point set matching is presented to suppress the area calculation error caused by image position offset and chips or built-up edges. 201 images were collected in two groups of cutting experiments for comparison with the proposed method and the other two methods, manual registration and non-registration. The results show that the proposed method's measurement values are closer to the actual values and have a higher measurement efficiency. Furthermore, the proposed indicator is sensitive to micro-scale changes to the blade edge, especially at the tip, and can be used as a supplement one to monitor tool wear more comprehensively.

Simulation of Work Hardening in Machining Inconel 718 with Multiscale Grain Size.

Machining nickel-based alloys always exhibits significant work-hardening behavior, which may help to improve the part quality by building a hardened layer on the surface, while also causing severe tool wear during machining. Hence, modeling the work-hardening phenomenon plays a critical role in the evaluation of tool wear and part quality. This paper aims to propose a numerical model to estimate the work-hardening layer for a deeper understanding of this behavior, employing both recrystallization-based and dislocation-based models to cover workpieces with multiscale grain sizes. Different user routines are implemented in the finite element method to simulate the increase in hardness in the deformed area due to recrystallization or changes in the dislocation density. The validation of the proposed model is performed with both literature and experimental data for Inconel 718 with small or large grain sizes. It is found that the recrystallization-based model is more suitable for predicting the work-hardening behavior of small-grain-size Inconel 718 and the dislocation-based model is better for that of large-grain-size Inconel 718. Further, as an important type of cutting tool in machining Inconel 718, the chamfered tools with different edge geometries are employed in the simulations of machining-induced work hardening. The results illustrate that the uncut chip thickness and chamfer angle have a significant influence on the work-hardening behavior.

Effect of diamond like carbon coatings on reducing sliding fit joint interfacial wear damage on Al5083 alloy

Wear is an important concept and is being given importance in different manufacturing industries. In every mobile joint, studies in interaction between sliding surfaces are very important. This is due to the wear that occurs in between the sliding surfaces. A lot of sliding fit joints are fabricated and used in production companies and transportation industries. In this manuscript, an attempt has been made to reduce sliding wear of Al 5083 alloy materials by coating it with diamond like carbon material. Using high velocity oxy fuel thermal spray coating, diamond like carbon materials were coated over Al 5083. Then it was subjected to wear testing by using pin on disc wear testing equipment. Wear tests were conducted by using petroleum lubricant and also in dry conditions. A considerable improvement in wear resistance was observed on using diamond like carbon coatings. Using scanning electron microscopy, the alloy Al 5083 material was evaluated for microstructural variations on conducting wear studies, before and after coating it with diamond like carbon material, with and without lubrication. The variations in coefficient of friction, specific wear rate and wear mass loss were studied under lubrication and without lubrication, with and without diamond like carbon coating. Microstructural evaluation of wear tested surfaces exhibited micro wear, micro voids, coating pull outs, abrasive wear and micro cracks.

Comparative Evaluation of Wear of Natural Enamel Antagonist Against Glazed Monolithic Zirconia Crowns and Polished Monolithic Zirconia Crowns: An In Vivo Study.

To comparatively evaluate the amount of wear of natural enamel against a glazed full coverage monolithic zirconia crown and a polished monolithic zirconia crown at 6 and 12 months. Thirty subjects within the age range of 18 to 35 years participated in this study. The subjects received a total of 60 single crowns, which were divided into two groups: (1) 30 glazed monolithic zirconia crowns opposed by natural enamel (group A); and (2) 30 polished monolithic zirconia crowns opposed by natural enamel (group B). Each subject received a crown from both groups, placed bilaterally in endodontically treated maxillary or mandibular first molars. An impression was made of the opposing arch at 24 hours, 6 months, and 12 months. The resulting casts were scanned with a 3D optical scanner. The recall scans were superimposed and compared to baseline scans using 3D AutoCAD software. A control group was included to compare the wear values to natural enamel against natural enamel. No significant difference (P = .855) was found in enamel wear between groups A (42.80 μm) and B (42.50 μm) after 6 months of use. However, a significant difference (P < .05) in enamel wear was found between group A (81.87 μm) and group B (71.43 μm) after 12 months of use. Glazed monolithic zirconia crowns cause more wear to the opposing enamel than polished monolithic zirconia crowns after 12 months of clinical use.

High-temperature oxidation and tribological behaviors of WTaVCr alloy coating prepared by double glow plasma surface alloying technology

Tungsten-based refractory high entropy alloys (RHEAs) are a potential candidate for plasma-facing materials (PFM) due to their excellent properties. However, the oxidation resistance of W-based RHEAs is poor. Moreover, there is still a lack of research on the evaluation of room temperature wear. In this work, several WTaVCr alloy coatings were fabricated by double glow plasma surface alloying (DGPSA) technology at different temperatures and different source ratios. The microstructure of WTaVCr coatings exhibited BCC solid solution phase. The coatings were compact and uniform. The scratch test indicates that the coating combines the substrate well. The surface hardness of the samples increases significantly after alloying, which is 5 times that of the substrate. Sliding wear tests were performed on the coating as well as the substrate. The fairly low specific wear rate of the coating (W31.7Ta13.3V42.9Cr12.2) proved its excellent wear-resisting property (The wear rate was 8 × 10−7 mm3/N∙m, which was two orders of magnitude lower than that of the substrate), and the dominant wear mechanism was abrasive wear and oxidative wear. The coating (W45Ta45.4V4.5Cr5.1) showed a favorable oxidation resistance, and a continuous Cr2O3 protective layer was formed on the surface. The oxidation resistance of the coating was approximately a quarter of the W-substrate.

Mechanical and Tribological Behavior of LM26/SiC/Ni-Gr Hybrid Composites

The study evaluates the mechanical and wear properties of LM26 alloy and its hybrid composites with silicon carbide (SiC) and nickel-coated graphite (Ni-Gr). LM26 aluminum alloy is generally known for its high strength, wear, and corrosion resistance compared to similar materials such as zinc and magnesium. The effect of Ni-Gr was studied, with 2 wt.% was found to provide the best mechanical properties. LM26 composites reinforced with varying percentages of SiC (0 to 30 wt.%) showed the best properties at 20 wt.% reinforcement after fabrication using a bottom pouring type stir casting setup (Two step feeding method). Evaluation of five hybrid LM26 composites through tensile strength, elongation, hardness, impact, porosity, and thermal studies showed that the LM26/2 wt.% Ni-Gr/20 wt.% SiC configuration showed the best filler composition for improved strength. Sliding wear evaluation using experimental and Taguchi analysis was performed at different configurations to identify the best wear resistance. Microstructure studies showed the presence of Ni-Gr particles forming coatings and temperature playing a significant role in the progression of the wear rate. Furthermore, the hybrid composite with 20% SiC and 2% Ni-Gr reinforcement showed the best wear resistance.

Hardening behaviour, mechanical properties and wear evaluation of TRIP/TWIP manganese steels: A comprehensive review

Steel is by far the most popular structural material in the world. Due to its excellent strength and hardness, non-magnetic manganese steel provides adaptability. The effect of SFE on induced plasticity is thoroughly explored together with several hardening behaviors, including strain hardening, grain size hardening, solid solution hardening, and precipitation hardening of manganese steel, showing the TRIP/TWIP phenomena. By a thorough literature analysis, the effect of TRIP and TWIP on the mechanical and sliding wear parameters of manganese steel is well shown. Steel that has a TWIP phenomenon can be produced commercially and improves strength by providing improved plasticity. The addition of microalloying components has a significant impact on intermetallic precipitation, which imparts hardness and strength to the steel. Manganese steel with the TRIP/TWIP phenomenon demonstrates greater resistance to sliding wear under both lubricated and unlubricated situations as a result of improvements in its mechanical characteristics.

Impact-abrasive wear resistance of high alumina ceramics and ZTA

In transport of raw materials abrasive wear resistance is a requirement, which can be met with alumina ceramics. At certain locations additional impact load occurs, exacerbating the wear loss. As literature on impact-abrasive wear of ceramics is scarce this topic will be researched in this work.We selected a variety of commercial alumina ceramics (90–96% Al2O3) and according to literature much more impact resistant – and substantially more expensive – Zirconia Toughened Alumina (ZTA, 20–25% Zr) used for wear resistant linings in impact dominated systems. We selected the Impeller-Tumbler test, an impact-abrasion test for wear evaluation of highly loaded ceramic edges. Two load regimes were evaluated for the abrasive, either corundum particles for severe load or steel balls for extreme load conditions. Correlation of wear results with the fracture toughness (K1C) and Vickers hardness of the materials is intended – material parameters used as measure for brittle failure of ceramics and wear resistance, respectively.The various ceramic materials showed very different wear behaviour under the impact-abrasive load. The 90% Al2O3 was least wear resistant under both load conditions. Interestingly large differences between the 92% types were found at extreme load conditions. The increase of alumina content to 95–96% showed remarkable benefits in both wear regimes. Best wear resistance against severe load was achieved by 25% ZTA, while it is comparable to the 95–96% high alumina types at extreme load.

A semi-automatic methodology for tire’s wear evaluation

In this work, the authors aim at developing a reliable and fast methodology to evaluate the wear evolution in tire starting from a complete optical 3D scanning. Starting from a data cloud, a semi-automatic methodology was implemented in MATLAB to extract mean tread radial profiles in correspondence of the desired angular position of the tire. These profiles could be numerically evaluated to establish the presence of irregular wear and the characteristic parameter of the groove depth. The reliability and the robustness of this methodology was firstly tested by applying it to several synthetic case studies modeled in CATIA V5®, where ovalization and presence of defects were also simulated. The groove depth was determined with an error lower than 1% for the ideal model, while the introduction of ovalization and defects leaded to an error of 2.6% in the worst condition. In a second time, the methodology has been successfully applied to experimental measurements carried out in two different wear life of the tire, allowing the tracking of the wear phenomena through the evaluation of the progressive lowering of tread radial profiles.

Tribological behaviour of polycarbonate urethane against Ti-6Al-4V for long-term resilient

Polycarbonate urethane has gained popularity as a bearing material to replace the existing hard polymeric materials in artificial joints. However, the viability of using polycarbonate urethane in artificial disc replacement over its metal counterpart is the challenge addressed in this research work. The present study is carried out to find the tribological behaviour of polycarbonate urethane against Ti-6Al-4V, which is the most frequently used endplate material in artificial disc replacement. The wear test is performed in pin-on-disc tribometer under lubricated condition using Hank's balanced salt solution with the variation in load as 10, 15, and 20 N, speed as 0.31, 0.63, and 0.94 m/s, and the number of cycles being 10,000, 25,000, and 50,000. A long-term wear evaluation is carried out to find the wear behaviour of polycarbonate urethane against Ti-6Al-4V. The wear is measured based on gravimetric analysis, and microscopic images are taken to analyze the wear pattern. The multi-objective optimization is also carried out to study the effect of control parameters. The wear pattern reveals that polycarbonate urethane has good tribological behaviour against Ti-6Al-4V. As the number of cycles increases, the polycarbonate urethane worn surfaces were found to be smooth. These results indicate that the polycarbonate urethane exhibits good resilience even after prolonged use.

Evaluation of articular cartilage wear against pyrolytic carbon in the context of spherical interposition shoulder arthroplasty

Metal shoulder hemiarthroplasty is known to cause failure due to glenoid cartilage erosion. Pyrolytic carbon (PyC), a non-metallic biomaterial, may be an attractive alternative due to its good general tribological characteristics and biocompatibility. We investigated the in vitro biotribological properties of PyC articulated against living cartilage for use as spherical shoulder interposition implant. The evaluation includes a comparison with the typically used cobalt‑chromium‑molybdenum alloy (CoCrMo) and zirconia toughened alumina (ZTA), a more recent biomaterial for hemiarthroplasty. The rate of cartilage degradation was assessed by means of cartilage wear biomarkers (glycosaminoglycans and hydroxyproline) in lubricant and histological changes of the cartilage superficial zone. In addition, the percentage of cell viability and metabolic activity of chondrocytes was assessed. The data revealed that PyC has similar tribological performance in terms of cell viability, cell metabolic activity, and tissue degradation compared to ZTA. Although not significant, CoCrMo affected chondrocyte metabolism and induced a thinner superficial layer with structural defects. There was a combined adsorption of phospholipids and biomarkers on the biomaterials; sGAGs adsorbed between 23 and 43% of the total concentration, and the adsorption rate of phospholipids increased significantly with friction. Biomaterial analysis is required to obtain the full picture of cartilage biomarker release and lubrication mechanisms. Our results suggest that PyC has good tribological performance and compares well with established biomaterials for hemiarthroplasty. It supports the use of PyC in spherical shoulder interposition implant as a viable alternative to conventional metal hemiarthroplasty. Further evaluation of the clinical performance of PyC is required.

Automatic Estimation of Drill Wear Based on Images of Holes Drilled in Melamine Faced Chipboard with Machine Learning Algorithms

In this article, an approach to drill wear evaluation is presented. Tool condition monitoring is an important problem in furniture manufacturing and similar industries. At the same time, approaches that rely on sets of sensors, often tend to be to robust or complex for the production environment. Instead of signals acquired from dedicated sensors, presented approach uses images of drilled holes as input data. Initial pictures are processed and enhanced in order to highlight the crucial properties. A set of selected features is then calculated on the resulting images, and later used during the training of 5 state-of-the-art classifiers. Presented research also evaluates number of images for consecutive drillings that needs to be taken into account in order to produce accurate results. From the selected set, the best performing classifier was Random Forest and it achieved close to 100% accuracy.

Multi-body dynamics analysis for the wear of front-rod bearing during the switching operation of railroad switches (Effect of adjustment condition)

Since the wear of front-rod bearings of railroad switches induce the switch failure, wear evaluation is indispensable. On the other hand, the various parts of railroad switches are adjusted so as to avoid derailment. For example, the attachment position of the adjustment nut of switch adjuster rod could enlarge the contact force between tongue rail and stock rail. The extension of front rod is also used to eliminate the gap between the toe of tongue rail and stock rail. In this paper, the bearing wear during the switching operation is estimated by multi-body dynamics simulation. The effects of the attachment position of adjustment nut and the extension of front rod are also evaluated. When the switch moves rightward, the driving force of electric point machine is transmitted to switch rod through switch adjuster rod. Then, the force is transmitted to right tongue rail through right switch rod bracket which connects switch rod and right tongue rail. Although the attachment position of adjustment nut controls the contact force between tongue rail and stock rail, that does not change the path of force transmission and the force acting on the bearing. Therefore, the attachment position does not affect the bearing wear. On the other hand, the extension of front rod changes the path of force transmission. The most of driving force of electric point machine is transmitted to the left switch rod bracket, front rod and right tongue rail in order. Therefore, the increase in the force acting on the bearing increases its wear. In the case of 6 mm extension of front rod, the estimated amount of wear is 3.44 μm, which is 3 times larger than the case of no extension.

Wide-bandwidth cutting force monitoring via motor current and accelerometer signals

Cutting forces are valuable for monitoring machining processes, as they allow the evaluation of tool wear, process stability, and workpiece quality. This paper presents a new non-intrusive method for monitoring cutting forces using a Kalman filter (KF) and Rauch-Tung-Striebel (RTS) smoothing. The method incorporates structural acceleration measurements as well as feed drive motor currents, thereby achieving wide estimation bandwidth and steady-state (DC) gain preservation. The KF + RTS smoothing are parameterized using spindle speed-sweeping cutting tests, which significantly reduces the experimental effort for model identification. The approach was validated in different machining conditions, which demonstrated good agreement with dynamometer measurements.

Evaluation of Retention and Attachment Wear of CAD/CAM Versus Conventional Implant-Assisted Overdenture Frameworks.

Previous studies have demonstrated problems with implant-supported overdenture attachments, such as denture base fracture and retention loss of the attachment's nylon insert. In this study, three implants were surgically inserted at the anterior mandibular region of 16 completely edentulous men (mean age: 50 years), divided into two groups depending on the received mandibular complete overdenture: a conventional metal-reinforced framework with prefabricated metal housing (Group I) or a CAD/CAM metal-reinforced framework with custom metal housing (Group II). At 3 months (prostheses loading), 6 months, and 12 months after implant placement, the retention of the mandibular dentures and wear of O-ring attachments were evaluated. Data were collected, tabulated, and statistically analyzed using Student t test. Statistically significant differences were found between the two groups and within the same groups during the evaluation period (P < .05). Attachment housing incorporated within a CAD/CAM implant overdenture can be a better alternative to the manufacturer's metal housing, as it diminishes retention loss and attachment wear over time, thus increasing patient satisfaction and chewing efficiency.

An evaluation of the long-term wear of a distal extension-removable partial denture on abutment teeth that have undergone periodontal therapy

Although the evidence is clear on the long-term effects of removable partial dentures (RPDs) on the periodontal health of abutment and non-abutment teeth, little work has been done on the periodontal outcomes of the remaining teeth previously treated with periodontal therapy. The aim of this study was to evaluate the effect of denture loading on teeth previously exposed to periodontal treatment with additional photo-disinfection. Twelve partially edentulous patients classified as having mandibular Kennedy Class I arches were included. In each quadrant of the mandibular arch, the terminal abutment was diagnosed to have untreated chronic periodontitis. Initially, all the affected abutments received a conservative periodontal treatment in form of scaling and conventional root debridement. Patients were randomly received additional treatment with photodynamic therapy in one of the mandibular quadrants (test group). After the periodontal treatment, a 4-week load-free period was planned. Mandibular distal extension RPDs was fabricated to restore the missing teeth. The clinical periodontal parameters including plaque index (PI), gingival index (GI), gingival recession (GR), probing pocket depth (PD), clinical attachment level (CAL) and tooth mobility (TM) were assessed at baseline, and then for two additional 6-month recall appointments over a period of twelve months after prosthetic treatment. In addition, the mean annual vertical bone loss was also assessed. Except for the PI, GR, and PD, values for the mean GI, CAL, and TM scores at the test group were significantly lower than those in the control group. Better annual vertical bone loss results were observed on the proximal sides of abutments treated with additional photodynamic therapy. The results of this study suggest that RPD abutments affected by chronic periodontitis may perform better as abutments for distal extension RPDs when treated with both conventional root debridement and additional antimicrobial photodynamic therapy.

Initial tool wear and process monitoring during titanium metal matrix composite machining (TiMMC)

When machining titanium metal matrix composites (TiMMCs), the abrasiveness of the reinforcement particles of this material leads to numerous machinability challenges, namely severe tool wear and poor machined surface quality. This paper aims to study the initial tool wear and the phenomena occurring during machining of titanium metal matrix composites. Initial wear refers to tool wear that occurs early in the cutting process. When the tool life is relatively short, the initial wear could significantly influence the remaining machining process. Therefore, a better understanding of the initial tool wear mechanisms and characteristics could lead to solutions extending the tool life, thereby improving the cutting process and production efficiency. Hence, the flank tool wear was assessed and thoroughly investigated using a scanning electron microscope (SEM), an energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). A tool condition monitoring system (TCMS) for online tool wear evaluation was employed to detect the transition times between wear stages during the machining process.Based on results, the types of wear in the initial zone were characterized. Abrasion, adhesion and cracking are considered as the critical morphological changes. The reduction of workpiece surface damage and tool wear rate could be related to the formation of a protective layer as a thermal barrier at the first transition time, when the initial tool wear ends and the steady state wear region begins. This moment, as the first transition time can be a short period, less than 15 s, which was detected by fractal analysis of force and vibration signals during machining of TiMMCs. The clear signatures of the transition times were suggested by the results of the fractal analysis.

Wear Evaluation of Copper-Nickel-Aluminum Alloys under Extreme Conditions

Cu-Ni-Al alloys at different concentrations were obtained using a high frequency induction melting unit, keeping a balance in the nominal compositions. Light alloys are important to be used in industrial applications. Aluminum additions result in a positive hardness increment of the ternary alloys in comparison with the binary Cu-Ni alloys. Generalized wear mechanisms of the alloys with low aluminum content are basically type abrasive, while samples with 5 and 10 at.% Al present an oxidative-adhesive wear mechanism. Wear results have indicated that aluminum addition affects positively the wear resistance, mainly in samples with high aluminum content product of the creation during the test of different oxides corresponding to the elements present in the alloys.

Study on In-Situ Tool Wear Detection during Micro End Milling Based on Machine Vision.

Most in situ tool wear monitoring methods during micro end milling rely on signals captured from the machining process to evaluate tool wear behavior; accurate positioning in the tool wear region and direct measurement of the level of wear are difficult to achieve. In this paper, an in situ monitoring system based on machine vision is designed and established to monitor tool wear behavior in micro end milling of titanium alloy Ti6Al4V. Meanwhile, types of tool wear zones during micro end milling are discussed and analyzed to obtain indicators for evaluating wear behavior. Aiming to measure such indicators, this study proposes image processing algorithms. Furthermore, the accuracy and reliability of these algorithms are verified by processing the template image of tool wear gathered during the experiment. Finally, a micro end milling experiment is performed with the verified micro end milling tool and the main wear type of the tool is understood via in-situ tool wear detection. Analyzing the measurement results of evaluation indicators of wear behavior shows the relationship between the level of wear and varying cutting time; it also gives the main influencing reasons that cause the change in each wear evaluation indicator.

Evaluation of weight wear of disc brake pads after test stands

The article presents the results of the research of a railway disc brake in the evaluation of the weight wear of friction pads. The tests were carried out on a certified brake stand where the friction and mechanical characteristics of the brake are determined. The stand was additionally equipped with a thermal imaging camera to observe the contact of the pads with the brake disc. Attention was also paid to examining the influence of such parameters of the braking process as the contact surface of the pad with the disc, the thickness of the pads as a determinant of their initial wear, the pressure of the pads to the disc, braking mass and braking speed on the weight wear of the friction pads.