Wear Values Research Articles

A Novel Wear Detection Method Based on FPC: A Case Study on the Hoisting Cage Sliding Sleeve

Under severe working conditions in mines, common wear detection methods are difficult to apply to the hoisting cage sliding sleeves. This article proposes a wear detection method based on flexible printed circuit (FPC), which is conceived for the wear detection of sliding sleeves or the edge of complex curved surfaces under severe conditions. First, a new type of sensor based on FPC is proposed, and its detection principle is presented. Then, according to the wear mechanism of sliding sleeves, a wear detection system is designed and manufactured. In order to express wear value, a formula about the relationship between the number of broken wires and wear value is established. Finally, a series of verification experiments are carried out, and the obtained results confirm the feasibility of proposed approach and explain the causes of voltage fluctuations.

Analytical study of “crosshead – slide rail” wear effect on pump rod stress state

The work presents an analytical study of “crosshead-slide rail” wear effect on stress state of a double piston pump’s rod. The authors proposed an engineering model of pump’s rod stress state and analytically analyzed a pump rod's stress state caused by wear of the “crosshead-slide rail” pair. It was stated, that wear values according to regulations and directive documents can refer to significant values of rod’s residual stresses. The numerical validation of the obtained results was carried out on for drill pump rods, including reinforced functional coatings.

Possibilities of 3D scanning of parts during repair of agricultural machinery

New high-precision and productive tools are needed due to the increasing requirements to the finishing accuracy of reworked parts and the assembly of units and machines in repair production. One of the most dynamically developing areas of digital production is the use of 3D technologies. They are most actively used in the aviation and automotive industry, as well as in the manufacture of machine elements from various parts. In recent years, there have been some publications on the use of 3D technologies in the repair of machines, including the reconditioning and hardening of parts. The current global trend is the creation of digital measurements and systems for contactless optical quality control of products. The paper and analyzes 3D scanning technologies developed by scientific and educational organizations, as well as presented at various international specialized exhibitions. The analysis and synthesis of information revealed that various laser scanners have been developed and used for 3D scanning, mainly for manufacturing quality control. The study analyzes the possibilities of their use to monitor the geometric parameters of parts of agric ultural machines during the input control of spare parts and repair of machines. 3D scanning has been found to improve measurement accuracy and performance compared to contact tools. The paper presents the main directions of 3D technologies in repair production. A promising area of introducing 3D technologies into repair production is the integrated use of additive technologies and 3D scanning. In case of fault detection using a 3D scanner, the wear value is determined, and the 3D printer recovers the wornout surface taking into account the non-uniformity of wear. Thus, the additive material consumption is reduced from 20 to 90%.

Środki trwałe w publicznej i prywatnej ochronie zdrowia w latach 1999–2018

Fixed assets in public and private healthcare in 1999-2018 The presented article deals with the subject of fixed assets in healthcare: their gross value, condition and degree of wear, broken down into the public and private sectors. Above the value grew extremely strongly in the analysed period, particularly impressive in private healthcare. The financing of this growth seems to have the largest share of funds obtained from EU and the EEA Financial Mechanism and the Norwegian Financial Mechanism as well as from public payer funds. The rate of increase of funds in healthcare from other public sources is significantly lower than, for example, the rate of GDP growth, which may indicate the withdrawal of state structures from healthcare financing. The increase in the degree of wear of fixed assets, which took place in the analysed period, may cause some concern.

ПРИМЕНЕНИЕ МЕТОДОВ АНАЛИЗА СОЧЕТАНИЙ РАЗМЕРОВ КОЛЕСНЫХ ПАР И ЭЛЕМЕНТОВ СТРЕЛОЧНЫХ ПЕРЕВОДОВ ДЛЯ ОПРЕДЕЛЕНИЯ РАЗМЕРОВ ЖЕЛОБОВ КОНТРРЕЛЬСОВЫХ УЗЛОВ

The paper considers methods for analysis of size combinations of wheelsets and elements of switches that are used at determination of dimensions of gutters for check-rail assemblies. The method of limit combinations, from the one side, doesn’t guarantee a reliable train operation on crossing assemblies in real operation, but, from the other side, it makes unreasonably strict demands to the design of the assembly. In order to eliminate the contradictions the paper proposes to use a method of probable compositions that allows not only solving an issue of limited safe dimensions of gauge and gutters, but also determining repeatability of impacts on check-rails in the most loaded cross sections and repeatability of motion paths of wheels on crossing. However, while using this method the authors have revealed a number of contradictions between calculated results and real operation. They show that it is possible to avoid the contradictions by the use of conditional probabilities method that allows calculating probabilities of phenomena for specific size combinations of gauge and gutters. As a result, the authors have concluded that it is the most accurate method of determination of permissible dimensions for gauge and gutters on switches. With the use of the method the authors have determined the maximal values of check-rail wear for straight track made of SP special profiles in conditions of nonexceedance of «impact effect» in bent part of the check-rail for switches with various angles.

ТРЕБОВАНИЯ К КОНТРРЕЛЬСОВЫМ УЗЛАМ СТРЕЛОЧНЫХ ПЕРЕВОДОВ

The paper is devoted to a problem of passing of rolling stock wheelsets with minimum deterioration of a crossing joint of a switch. The authors have formulated criteria representing necessary and sufficient requirements, on the basis of which it is possible to determine permissible values of check-rails wear and dimensions of their gutters. The paper also presents a method for calculation of rolling stock passage on the crossing joint equipped with check-rails that are not connected to running rails. With the u se of the experimental and calculation method the authors have highlighted stages for determination of stress-strain condition of check-rails. The have analysed the operation of check-rails made of RK special profiles that are mounted to a running rail by inserts. As a result, the authors have assessed the advantages of application of check-rails with mounts that are not connected to running rails. Since the method of check-rails calculation for the operation in other parts of the switch is similar, they have analysed the operation of a protector checkrail for switches and discussed the efficiency and disadvantages of its application.

On Fashion Industry Status and Design Innovation Strategies for Chinese Leather

The leather fashion industry has always been one of China’s important industries with a higher degree of industrial agglomeration and internationalization. After 30 years of precipitation, adjustment and reform, it is now marching towards a stage of in-depth innovation. Based on the analysis of the current situation of the leather industry and leather wear design, this paper puts forward the main status and problems faced by the Chinese leather wear design: style convergence, seasonal limitations, environmental issues, and talent problems. According to the characteristics of materials, craftsmanship and structure of leather wear, this paper attempts to propose specific design strategies from the following perspectives: design resource integration, design methods, design thinking, and collaborative innovation. These perspectives provide the following four aspects of innovation strategies for advancing the overall desgin level as well as design value for Chinese Leather wear: integration and optimization of design resources, innovation in design methods, improvement of design thinking, cross-border collaborative innovation and joint efforts of the government, enterprises, and colleges. On this basis, this paper explores and studies development ideas, and thus puts forward four suggestions on new directions of Chinese leather wear design, that is technology, refinement of positioning, branding and sustainability.

Prediction of tool wear in CFRP drilling based on neural network with multicharacteristics and multisignal sources

Carbon fiber-reinforced polymer (CFRP) drilling is a typical process in the aircraft industry. Because the components of CFRP are different and uneven, it is difficult to extract tool wear characteristics from the machining signals, which are composed of the processing characteristics of various materials and the tool state characteristics. The aim of this work is to present a new comprehensive approach based on multicharacteristics and multisignal sources to predict the tool wear state during CFRP drilling through a combination of a backpropagation (BP) artificial neural network (ANN) model and an efficient automatic system depending on the sliding window algorithm. It was verified that the peak factor and Kurtosis coefficient of different signals and the energy value of the d5 layer of the thrust force signal and the d3 layer of the vibration signal after wavelet decomposition were related to tool wear. Among them, the energy value of the d3 layer of the vibration signal was selected as the wear indicator and was able to describe the state of the tool during the CFRP drilling process regardless of the drilling conditions and individual tool differences. A confirmatory drilling experiment using 6-mm-diameter polycrystalline diamond twist drilling under different processing parameters was conducted to verify the ANN model based on multicharacteristics and multisignal sources. A lower feed speed and a higher cutting speed were both highly correlated with the VB value of flank wear. Drill wear accelerated because of the occurrence of adhesive wear when the number of drilled holes reached around 90. The accuracy of the neural network model is 80–87% when using the value of only one characteristic but clearly increases based on multicharacteristics and multisignal sources in real time, indicating that the BP ANN model has higher accuracy in predicting the tool state in CFRP drilling through the sensor signal fusion method.

Investigation of the Influence of Non-Flatness and Runout of Friction Discs on the Service Life of Machine Clutches

In the manufacture of discs, it is important not only to ensure their specified geometric accuracy and correct shape, but to maintain geometric parameters during operation. The method of testing disks on the IKS-T inertial test bench is described. The main units of the test bench and the loading parameters of the disks are indicated. Research has been carried out on the influence of the runout and non-flatness of friction discs on the service life of the clutches. Bench tests made it possible to determine the optimal runout range of discs up to 0.8 mm, which ensures an increase in the reliability of the clutches by 30 % due to a decrease in the wear of the friction discs. In addition, the test results show that with a decrease in non-flatness from 1.2 mm to 0.3 mm, the service life of the friction discs increases by 16 %, i.e. wear of discs in the running-in mode with distortions in geometry occurs more intensively than for discs with a flat surface. With an out-of-flatness value of 0.3 mm, the discs acquire improved elastic characteristics. It was possible to determine that increased values of disc wear are observed mainly along the outer diameter, due to the runout and higher sliding speed compared to the sliding speed on the inner diameter. Calculated dependences of the limiting number of loading cycles on the beating and non-flatness of discs are presented. It was found that when testing discs with the non-flatness less than 0.3 mm, disc wear appears with the formation of “poppet” disc shape. For the purpose of imparting the correct shape to the products with the exclusion of “poppet” discs, a dynamic straightening with combined loading is proposed. The resulting calculated dependencies will be used in the design of industrial universal installations for cyclic alternating bending of friction discs.

Tool wear analysis in milling of locomotives wheels

The present work aims to evaluate the tool wear during the milling process of locomotives wheels—class C. A digital microscope is used to identify both the wear and the damage. The wear or damage, when propagated, can compromise the wheel roughness, which has a significant economic importance to railroad maintenance. A system for image capture composed of an ISM-PM200S INSIZE Digital Microscope and the ISM-Pro software is used to measure the flank wear. Firstly, milling process is applied with different numbers of passes. The results showed that, after flank wear, the most common wear is the thermal crack. It is also possible to observe the appearance of chipping and fracture as a consequence of the combination of thermal and mechanical cracks in the same insert. The inserts are more damaged in the raceway, due to the hardening of this region during its use. Inserts in the frieze region also showed higher values of wear, justified by the conditions of the railway. The highest values observed are around 0.1 mm. It is possible to notice that some inserts showed other damages, such as breaks and chipping, even before reaching the end of life due to wear.

CAE Modeling of Hot Stamping Tool Wear

To assess the wear of the hot stamping tool, a model of punch deformation under the influence of thermal and mechanical loads was developed. The shape and relative position of the punch and die were designed to localize maximum contact loads at a predetermined location. It was assumed that the punch wear is caused by a removal of the surface metal layer, due to decreasing its mechanical strength during hot plastic deformation. Simulation was performed by the finite element method in the Deform software package. A temperature field and wear pattern in the contact zone were calculated. With respect to the loads typical for hot forging railway wheels, the comparison showed that the wear in a numerical experiment is of the same level as the actual value of wear.

Flooring characteristics of thermo-mechanical densified wood from three hardwood tropical species in Costa Rica

Densification is one method used to modify low-density woods to make them achieve the hardness required for flooring application. The purpose of this study was to investigate the effect of thermo-mechanical densification with pre-heating in wood of Alnus acuminata, Vochysia ferruginea and Vochysia guatemalensis from, seeking to stabilize and reduce spring-back of the densified wood and evaluate its performance in flooring applications. The results showed that the wood of the three species turned dark. This is because brightness diminished and yellowness and redness increased. Weight loss due to pre-heating was statistically higher in V. ferruginea and V. guatemalensis. The final density and spring-back were statistically similar in the three species. The percentage of densification of A. acuminata and V. guatemalensis were statistically higher than for V. ferruginea and the degree of compression was statistically higher in V. guatemalensis. As for flooring evaluation, the percentage of densification, temperature and time of pre-heating affected the behavior of densified wood flooring. The low percentage of densification and high weight loss in the pre-heating stage caused greater values of wear, wear index, residual deformation, residual indentation for the falling ball indentation test, and more damages in the surface indentation test in wood of V. ferruginea

ПРОЕКТИРОВАНИЕ КАЛИБРА-СКОБЫ ДЛЯ КОНТРОЛЯ ДИАМЕТРА ПРОМЕЖУТОЧНОГО ВАЛА ПРИ РЕМОНТЕ ДВИГАТЕЛЕЙ ЗМЗ

Two goals can be achieved in repair production when controlling linear dimensions, depending on the task at hand. First, measurement is taken to determine the size of the controlled part in absolute terms. Then, the size of the controlled part is determined within the prescribed maximum deviations. According to the measurement results, the part is classifi ed as suitable or rejected. The second goal is achieved with the help of calibers, which signifi cantly increases the speed and reduces the labor intensity of control. But standard gauges are not available for repair dimensions and tolerances, so an individual approach is required. The authors off er a snap-gauge project including staples for serial repair production to control the diameter of the front journal of the countershaft of ZMZ engines during repairs. The technology includes grinding for a sleeve of the repair size and ensuring the quality of fi t in the joint of 48.8 mm. The tolerance for the production of the go and no-go sides equals 7 microns. To provide a margin for wear, the shift into the tolerance fi eld by the go side of the snap-gauge should amount to 6 microns. The calculated limiting wear value equals +5 microns. To control the dimensions of the working snap-gauge during operation, it is necessary to use a control gauge. The authors determined the tolerance for the dimensions of the control gauge that equals 2.5 microns and established the limiting dimensions of the gauge. Taking into account the obtained values, the authors have constructed a diagram of the tolerance fi elds of the snap-gauge for controlling the shaft size of 48.8 mm with upper and lower deviations of –0.041 mm and –0.016 mm, respectively, and made a sketch of the developed measuring instrument.

Influence of Mineral Supplementation on the Composition of Goat Milk.

Eighteen monoparousLactating West Afriacan Dwarf (WAD) does, with average weight of 25 土 0.80kg were used in a 12-week feeding trial to examine the effects of dietry mineral supplementation (Dicalcium phosphate and MgSO4 .7H2O) on milk production and composition of Ca. P and Mg The docs were grouped into three of six animal replicate/group and randomly assigned to each of the three isonitrogenous (15% CP) and isoenergetic 9.81MJ/kg ME) Supplementary diets (A, B,, and C) respectively. The supplementary diet contained graded levels (0.5, 1, and 1.5% of Dicalcium phosphate and MgSO4.7H20 and fed with a basal diet of cyndom nlemfeuns grass in a completely randomized design. Results showed that treatment effects on dry matter intake (DMI (g/dry/kgB )circulating levels (mg/100ml) of ca, P and Mg in milk and sera of WAD does were significant (P <0.05), Variations observed on milk wal said were not significant (P >0.05. Significant (p<0,05) dry matter intake (DMI) (g/day/kgBW) values of 155.55, 174.77 and 193.34 were obtained for does on diets A, B and C respectively; While corresponding significant (P < 0.01) mean milk value of 185.30, 301.20, and 340.05 g/day were obtained significantly different (P<0.05) wear values of Ca, P and Mg levels obtained milk of WAD does on diets A, B and C were: Ca. 121.0, 127.0 and 132.0; P. 84.5, 89.78 and 94.08; and Mg: 18.90, 41.87 and 47.61(mg/100ml); while corresponding values in serumn were Ca: 9.75, 10.0 and 10.13. P: 7.15, 7.57 7.79; and Mg: 3.20, 3.52 and' 4.54 (mg/100ml)respectively.Significant (P < 0.05) positive correlations (r- 0.99, 0.97 and 0.73) existed between and serum Ca, P and Mg contents respectively, suggested that blood is a Secondary source of milk mineral secretion in lactating animals. The general trend was that increasing dietary mineral supplementation resulted in concomitant Increase in dr matter consumption, milk yield and milk mineral (Cu, P. and Mg) contents with does and diet C recording In the best performance. Consequently, dietary Ca. P and Mg levels %DM) in supplementary lactation diet for indigenous WAD goats seemed to be best at 0.43, 0.35, and 0.17 respectively

Modified Taylor’s equation including the effects of fiber characteristics on tool wear when machining natural fiber composites

This study aims to give an understanding on the effects of diverse natural fibers on the mechanical properties and wear behavior of high-speed steel tool when machining polypropylene (PP) based natural fiber-reinforced composites (NFRCs). Rice husk (RH), jute and kenaf of 30 wt% each with notable differences in silicon content, hardness and aspect ratio values are used as reinforcements. The influence of worn-out tool on surface finish, machining force and work-tool interface temperature has also been elucidated. The microscopic analysis has enabled us to identify the distinct tool lives and wear mechanisms for the machined NFRCs demonstrating: (i) rigorous mechanical abrasion with strip chipping, cracks, galling and large nose deformation for RH/PP; (ii) less severe abrasion combined with adhesion and attrition wears for jute/PP; and (iii) mild abrasion/scratch marks with attrition wear and formation of protective/transfer layer for kenaf/PP composites. A remarkable difference has been observed in the flank wear values, such as VB = 0.25 mm after 55 min of machining for kenaf/PP composites whereas VB = 0.3 mm within 6 min for RH/PP. The machined surface textures generated by the worn tools reveal a plowing mechanism for RH/PP and jute/PP composites while shearing type for kenaf/PP composites. Overall, kenaf/PP composites prove to have superior mechanical and machinability characteristics in comparison to RH/PP composites, which reveal inferior outcomes. For the first time, a modified Taylor’s tool life equation, including silicon content and reinforcement aspect ratio has been derived with an error <18%.

Analysis of Surface Roughness and Flank Wear Using the Taguchi Method in Milling of NiTi Shape Memory Alloy with Uncoated Tools

The aim of this study was to optimize machining parameters to obtain the smallest average surface roughness (Ra) and flank wear (Vb) values as a result of the surface milling of a nickel-titanium (NiTi) shape memory alloy (SMA) with uncoated cutting tools with different nose radius (rε) under dry cutting conditions. Tungsten carbide cutting tools with different rε (0.4 mm and 0.8 mm) were used in milling operations. The milling process was performed as lateral/surface cutting at three different cutting speeds (Vc) (20, 35 and 50 m/min), feed rates (fz) (0.03, 0.07 and 0.14 mm/tooth) and a constant axial cutting depth (0.7 mm). The effects of machining parameters in milling experiments were investigated based on the Taguchi L18 (21 × 32) orthogonal sequence, and the data obtained were analyzed using the Minitab 17 software. To determine the effects of processing parameters on Ra and Vb, analysis of variance (ANOVA) was used. The analysis results reveal that the dominant factor affecting the Ra is the cutting tool rε, while the main factor affecting Vb is the fz. Since the predicted values and measured values are very close to each other, it can be said that optimization is correct according to the validation test results.

Kajian Simulasi Fem 3D : Keausan Pahat Twist Drill pada Pemesinan Bor Mikro Material Ti-6Al-4V

Titanium is a material that has a good strength to weight ratio, excellent corrosion resistance, and resistant to high or low temperatures Titanium alloys that are used in various industrial fields, one of them is the Ti6Al4V alloy. Micro drilling has a high rotational speed which results in tool wear, high temperatures, and surface roughness. This research uses The Finite Element Method (FEM) simulation. The application used is DEFORM 3D based on parameters from previous studies. The purpose of this research is to identify the progress of tool wear in a simulated manner on the Ti6Al4V alloy micro-dilling and analyze the tool wear on the Ti6Al4V alloy micro-drilling under dry machining conditions. Machining trials used CNC micro-drilling at various of cutting parameters such as cutting speed of 10.000 and 15.000 rpm. The results showed that the tool wear progress at the 5th hole was 0.00346 mm, the tool wear progress at the 10th hole was 0.00462 mm and the tool wear progress at the 15th hole was 0.00525 mm. Analyzing tool wear in simulated machining and experimental machining in dry conditions has a high wear value. Tool wear is simulated by measuring the radius of the tool in the 15th hole valued at 0.09973 mm. Tool wear is experimentally measured from the tool radius in the 15th hole valued at 0.0101 mm. The tool mesh is changed due to the tool wear. The tool mesh in the 5th hole is worth 17372 mesh. The tool mesh in the 10th hole is 15662 mesh. The tool mesh in the 15th hole was highly reduced by 13021 mesh. Tool wear affects the change in tool mesh. With increasing tool wear then tool mesh is reduced. The next cause of tool wear is the tool temperature in the machining process.

Study on the Effects of the Wear-Rings Clearance on the Solid-Liquid Two-Phase Flow Characteristics of Centrifugal Pumps

In order to study the wear law of the centrifugal pump flowing surface under different wear-rings clearance, the McLaury wear model was used to conduct the full-passage numerical simulation of solid-liquid two-phase flow in a single-stage single-suction centrifugal pump. The reliability of the numerical calculation method is verified by comparing the experimental data and numerical simulation results. The clearance is 0.1, 0.15, 0.2, 0.3 and 0.5 mm, respectively. The results show that the wear of the centrifugal pump blades is mainly concentrated in the end part and the inlet part of the blade, and the wear of the pressure surface at the end of the suction surface and the front of the blade is more serious. As the clearance increases, the maximum wear value in the impeller increases first and then decreases, reaching a maximum at 0.15 mm. With the increase of the clearance, the wear degree and the wear rate of the volute wall surface first increase and then decrease, and reach the maximum at 0.2 mm. With the increase of the clearance and the concentration of the fluid medium, the wear at the clearance of the centrifugal pump is more serious, and the severe wear area exhibits a point-like circumferential distribution.

Investigation on sliding wear behaviour of walnut shell powder (WSP) filled polyester composites using finite element method

Walnut shell powder (WSP) is an agro-waste material generated in all over the world, primarily has no important use. In this study, an attempt has been made to utilize this waste as reinforcement in particulate filled polymer composite. Such polymer composite samples are fabricated with varying proportions of WSP filler content and unsaturated polyester resin. WSP-polyester composite samples are subjected to dry sliding wear test by pin-on-disc test machine according to L9 orthogonal array of Taguchi’s experimental design. The impact of different input factors on the wear behaviour of the WSP-polyester composites has been analyzed and also the best possible combination of these factors for the minimum specific wear rate is determined. Commercially available FEM-based simulation software is also utilized to assess the specific wear rate of the WSP-polyester composites. The wear values predicted by ANSYS 19.R2 are validated with the measured data and found to be in with close agreement.

Impact of simulated toothbrushing on surface properties of chairside CAD-CAM materials: An in vitro study

Statement of problemChairside computer-aided design and computer-aided manufacturing (CAD-CAM) materials that do not require any firing steps are a promising option to expedite restoration production; however, little information is available to determine the most suitable material for each clinical situation. PurposeThe purpose of this in vitro study was to evaluate the effect of simulated toothbrushing on surface gloss, roughness, and wear of chairside CAD-CAM materials. Material and methodsDisk-shaped specimens (n=15) were prepared of the following materials: ENA—VITA Enamic; LAV—Lava Ultimate; EMP—IPS Empress CAD; CER—Cerasmart; GRA—Grandio blocs. Gloss (Gloss Unit—GU) and surface roughness (Ra—μm) were evaluated before and after simulated toothbrushing (100 000 strokes). Wear (μm) was assessed by contact profilometry. Additional analyses of microhardness by scanning electron microscopy were also performed. Data were analyzed with 2-way repeated measures ANOVA test for roughness and gloss, and 1-way ANOVA for wear (α=.05). To estimate the correlation between Ra and GU, the Pearson correlation was calculated. ResultsBefore brushing, CER showed the lowest Ra (P<.001), and GRA the lowest GU values. After brushing, the feldspathic ceramic-based materials (ENA and EMP) presented the highest gloss, whereas the ceramic group (EMP) showed the lowest Ra. Before and after brushing, GRA showed the lowest GU values. Higher wear values were found for the composite resin groups (CER>GRA), with the exception of LAVA, which was similar to ENA, and EMP showing improved wear resistance. A strong negative correlation (-0.925) between GU and Ra values was detected (P<.001). ConclusionsThe materials containing a glass phase (ENA and EMP) presented higher wear resistance, higher gloss, and lower roughness after brushing than the other materials tested. The correlation test showed that the higher the surface roughness, the lower the gloss.