Roller Hardness Research Articles

Influence of thermal history and consolidation force on wedge peel strength of CF/PEEK laminates manufactured by laser‐radiated in‐situ consolidation

AbstractProcessing parameters during the laser‐radiated in‐situ manufacturing process change the thermal history of the thermoplastic composite, which affects porosity and fiber‐resin interfacial bonding quality, and hence the wedge peel strength of the laminate. The effect of different laser powers and consolidation forces on the wedge peel strength of the specimens was investigated. Due to the fiber‐rich area on the tape surface during the laser heating phase as well as the insufficient consolidation force and consolidation length during the consolidation phase, the wedge peel strength decreased due to increased porosity and weak fiber‐resin bonding at the interlayer bonding interface. A conformable consolidation roller of lower hardness was used to improve the wedge peel strength of the laminates, which reduced the initial temperature of the cooling phase, thus inhibiting the void rebound and increasing the bonding strength at the fiber‐resin interface. The cross‐section and peeling surface were characterized by optical microscope and scanning electron microscope. The wedge peel strength of the laminates, with reduced voids and increased interfacial bonding strength between the fibers and the resin, is improved.Highlights Mechanism of void formation and evolution in different phases of laser‐radiated in‐situ consolidated laminate. Effect of consolidation roller hardness and deformation on wedge peel strength.

Prioritising Yarn Quality Via Varying Top Roller Hardness: A Fuzzy Application

In recent years, the spinning or yarn manufacturing sector has seen remarkable technological advancements, emphasizing high-quality yarn production, especially for cotton combed ring spun yarns. In the case of better quality ring spun combed yarn, each part of the ring frame is significant. To fulfil this issue, this study focuses on understanding the impact of the drafting roller hardness on cotton-combed ring-spun yarn quality. It delves into how ten top and bottom roller hardness combinations influence yarn quality parameters. The cotton combed yarns underwent rigorous testing after spinning on ring frames with varying drafting roller hardness. Key quality parameters studied included yarn Imperfection Index (IPI), Unevenness (Ue%), Hairiness (Hi), Elongation at break (Eb%), and Count Strength Product (CSP), and Tenacity (Te). The primary insight was that extreme roller hardness adversely affects all parameters except Elongation at the break value obtained for the shore hardness value of 80/83. Yarns produced using medium-hardness rollers showcased fewer imperfections due to more consistent fibre flow and minimized drafting slippages, resulting in an even twist. These findings are pivotal for the yarn manufacturing industry, hinting at potential refinements in production methods. The usage of the Fuzzy DEMATEL (Decision-Making Trial and Evaluation Laboratory) methodology also determined that Te CSP) and IPI values significantly influence the combed yarn quality when adjusting roller hardness, whereas Hi is the least influential. Therefore, this study offers twofold insights: determining the optimal roller hardness and identifying the most affected quality parameters.

Analysis of Rubber Roller Coating and Influence of Rubber Roller Characteristics on the Coating Thickness

This paper has got the relationship between coating thickness and roller radius,speed, viscosity,elastic modulus,load,which is through the analysis of rubber roller’s coating flow mathematical model,and verify the elastic modulus and the load force on the coating thickness through the experimental methods. Experiments show that the coating thickness is inversely proportional to the elastic modulus and the load force.In conclusion, the diameter of the roller, the range of load imposed on the rubber roller, the hardness of rubber roller hardness, the suitable viscosity range and the speed limit must be taken into account during the design of the five rollers solvent-free coating system.

The Effect of the Ring Spinning Machine Top Drafting Roller Hardness and the Fiber Blend Ratio on the Quality of Yarn

The ring spinning machine, in which the fibers are converted from the roving form to yarn, applies higher draft than the roving frame and roving frame. The rate and control of this draft has a great importance on yarn quality. During this controlled shooting, the hardness of the upper drafting rollers and the size of the clips placed on the aprons are of great importance. The cot stiffness and the clip type determine the dimensions of the fiber clamping surface between the rollers. The hardness of the upper roller used, the pressure applied to the top rollers, the type of clips that adjust the distance between the top and bottom rollers are the parameters that control the controlled drawing in this context. The aim of this study is to improve the yarn quality by changing the cot stiffness. For this, two different experimental factors were chosen to investigate the effect of cot stiffness and fiber type on yarn quality. The first factor is the upper roller hardness at three different lower levels, 70, 76 and 83 shore. The second factor is the fiber type, and the fiber type has two different sub-levels. In this context, the yarns consisting of different fibers planned to be produced are 20/1 Ne 50/50 cotton/acrylic and 20/1 Ne 100% acrylic yarns. Unevenness, thin/thick place, neps, hairiness and strength tests were carried out on the produced yarns. The results obtained were analyzed statistically and the effect of cot stiffness and fiber type on yarn quality was revealed.

Fractographic analysis of fracture features of a slugger punch and profile bending roll made of Kh12MF steel

A slugger punch and a roll forming roller made of C1.5Cr12MoV steel destroyed during operation are studied. It was established by spark spectrometry that the steel was up to the requirements for the chemical composition. Metallographic studies have shown that the steel structure represents martensite with carbides precipitates along the grain boundaries. Typical of this steel grade sulfides were found in the structure by the method of energy-dispersive X-ray spectral microanalysis. Fractographic analysis of fractures made it possible to determine the location of the initial crack and the subsequent fracture nature of the tool. The punch geometry discrepancy to the drawing is established. Its working surface has a one-sided slope. This fact led to unequal lateral stresses and brittle fracture of the punch support surface. Wear marks and transverse cracks were found on the roller working surface. They are caused by high contact stresses in conjunction with the difference in relative speeds of the roller surface and the workpiece. The propagation of main cracks in the radial direction of the roller led to its fatigue failure. Measurements of the punch and roller hardness by the Rockwell method revealed a deviation of the values from the normative documentation. It is found that the punch has extra hardness, which increases the fragility of the tool and reduces its resistance to impact loads. The working surface hardness of the roller is lowered, which leads to a decrease in the strength characteristics of the tool. Thus, the destruction of the tool was caused by the uneven action of operating stresses in combination with a violation of the recommendations on the tool hardness.

ИЗНОСЫ ПРАВОГО НОЖА СКОРОСТНОГО ПЛУГА ПСКУ И ТЕХНОЛОГИЧЕСКИЕ МЕРОПРИЯТИЯ ПО УВЕЛИЧЕНИЮ ЕГО ДОЛГОВЕЧНОСТИ

The intensification of crop production has led to the creation of equipment for high-speed tillage. The high speed of plowing causes an increased intensity of wear of the working bodies of plows. The limit capacity of the vertical knife when processing loamy soils is about 30 hectares, after which the body must be subjected to repair (maintenance) operations. (Research purpose) The research purpose is in studying the wear of the right knives of the PSKU plow (geometry and location on the working surface), assessing the technical condition and develop measures to improve their durability. (Materials and methods) The right knife (plowshare) performs the function of a pruning element, its design corresponds to the design of the plowshare in the classic version, but with reduced dimensions. We carried out wear control in width and thickness on 14 parts. (Results and discussion) The knives after working 30 hectares are suitable for further use in width. The width of the solid layer deposited on the back side is about 7-8 millimeters, so additional surfacing of the abrasive-resistant alloy is necessary. The wear on the thickness of the knife cannot be the reason for its decommissioning, since the strength and rigidity are preserved, and the agrotechnical requirements for soil cultivation are not violated. (Conclusions) The residual width and thickness of the studied knives when plowing loam retain the normalized limits, which indicates the possibility of their further operation, but it is necessary to weld the cutting-blade part from the back with an abrasive- resistant alloy. The xiphoid wear is fused with an electrode that provides a roller hardness of about 50 HRC. A low level of wear rate of the part is achieved due to the hardness of the blade area 60 HRC.

Study the effect of roller hardness on the surface properties of burnished AISI 1211 steel

Study the effect of roller hardness on the surface properties of burnished AISI 1211 steel

Study the effect of roller hardness on the surface properties of burnished AISI 1211 steel

This work aims to study the effect of roller hardness on the surface quality of AISI 1211 burnished steel surfaces. High-speed-steel rollers with untreated and cryogenic treated conditions are employed for roller burnishing. Cryogenic treatment is carried out at the temperature of −180°C for 36 hours in a liquid nitrogen bath followed by tempering at 200°C for six hours. CNC turning centre is employed for roller burnishing. The surface quality is measured in terms of surface roughness and hardness against the function of three different turning parameters namely spindle speed, feed rate and depth of penetration. The average hardness of cryogenic treated rollers is increased from 380 Hv0.5 to 625 Hv0.5. The results revealed that increasing the spindle speed significantly affected the surface finish and increase in roller penetration depth increases the hardness of AISI 1211 steel surfaces. Cryogenic treated rollers provide better surface finish and hardness on the AISI 1211 steel samples than untreated rollers.

Prediction of Blended Yarn Evenness and Tensile Properties by Using Artificial Neural Network and Multiple Linear Regression

Abstract The present research work was carried out to develop the prediction models for blended ring spun yarn evenness and tensile parameters using artificial neural networks (ANNs) and multiple linear regression (MLR). Polyester/cotton blend ratio, twist multiplier, back roller hardness and break draft ratio were used as input parameters to predict yarn evenness in terms of CVm% and yarn tensile properties in terms of tenacity and elongation. Feed forward neural networks with Bayesian regularisation support were successfully trained and tested using the available experimental data. The coefficients of determination of ANN and regression models indicate that there is a strong correlation between the measured and predicted yarn characteristics with an acceptable mean absolute error values. The comparative analysis of two modelling techniques shows that the ANNs perform better than the MLR models. The relative importance of input variables was determined using rank analysis through input saliency test on optimised ANN models and standardised coefficients of regression models. These models are suitable for yarn manufacturers and can be used within the investigated knowledge domain.

Effect of ink transfer on print mottle in shrink films

The gravure printing process is considered a pioneer in long run package printing jobs, offering exceptional print quality teamed with high quantities. Shrink films, primarily polyvinyl chloride (PVC) and polyethylene terephthalate-glycol modified (PET-G) are extensively printed using the rotogravure printing process. The intricacies of the printing process and the complex nature of the interactions between the substrate, ink, and printing press, if not studied and controlled, can contribute to unnecessary variation and degradation in print quality. Printability not only can be approximated in the dimensions of densitometry and spectrophotometry, but can also be gauged by print defects such as mottle. This study investigates the effect of process parameters, viz., line screen, ink viscosity, printing speed, and impression roller hardness on print mottle, and explores a way to minimize the same. Design of experiments were generated and analyzed through analysis of variance, main and interaction effects. Furthermore, a regression model was generated to predict the print mottle. The predicted values from the model were in close agreement with the press results. The optimization of process parameters resulted in reduction of print mottle in solid printed areas by 34% and 51% on PET-G and PVC, respectively.

엔지니어링 세라믹스의 경면연마를 위한 효율적인 슈퍼피니싱 조건의 결정

The Engineering ceramics have some excellent properties as materials for modern mechanical and electrical components. It is, however, not easy to polish them efficiently because they are strong and hard. This study is carried out to obtain a mirror surface on engineering ceramics by surperfinishing with high efficiency. To achieve this, we conducted a series of polishing experiments using representative engineering ceramics, such as <TEX>$Al_2O_3$</TEX>, SiC, <TEX>$Si_3N_4$</TEX> and <TEX>$ZrO_2$</TEX>, using diamond abrasive film from the perspective of oscillations peed, the rotational speed of the workpiece, contact roller hardness, contact pressure and feed rate. Furthermore, the polishing efficiency and characteristics for engineering ceramics are discussed on the basis of optimal polishing time and surface roughness. Our results confirmed that efficient superfinishing conditions and polishing characteristics of engineering ceramics can be determined.

Determination of efficient superfinishing conditions for mirror surface finishing of titanium

To determine mirror surface finishing conditions and efficient and economical superfinishing conditions for pure titanium and titanium alloys, an abrasive film is used when superfinishing is performed under varying conditions. These conditions include the workpiece rotation speed, the oscillation speed, the contact pressure of the roller, the hardness of the roller, and the type of abrasive film. The superfinishing device is applied to polishing a thin and long cylindrical bar. A micro-finishing film and a lapping film were used as abrasive films. Al2O3 grains or SiC grains were used as abrasives. The surface roughness of a polished workpiece was measured using a stylus-type surface-roughness measuring instrument. As a result, the conditions to improve the polishing surface efficiently include high values for the workpiece rotation speed, oscillation speed and contact pressure. The roller hardness has no effect on the efficient polishing conditions. The mirror finish of a surface can be created using lapping film of 3 μm with Al2O3 grains after polishing to a steady surface roughness under the efficient polishing conditions.

The Determination of Efficient Super Finishing Conditions for the Mirror Surface Finishing of Titanium

Recently, the demands for superfinishing machines have increased, but the development of superfinishing devices and superfinishing technology remain insufficient. And titanium, with its infinite potential, is widely known as a highly ideal material. It is therefore used in various industries that require precision-machined parts, such as the automobile, chemistry and aerospace industries, due to its outstanding specific strength and corrosion resistance compared to any other alloys. In this study, a series of experiments was performed to determine the mirror surface finishing conditions of titanium as well as efficient superfinishing conditions that can be utilized practically and economically at production sites. The applied conditions were the workpiece rotation speed, the oscillation speed, the contact pressure, the roller hardness and the type of abrasive film used when superfinishing was performed using an abrasive film for titanium-based materials such as pure titanium and titanium alloy. From the experiments, it was confirmed that efficient superfinishing conditions and mirror surface finishing conditions were determined for pure titanium and titanium alloy.

Dry sliding wear behaviour of plasma transferred arc hardfaced colmonoy surface

Dry sliding wear occurs when two bodies are in sliding contact. During the process of sliding, fragments may be pulled out from one surface and they may stick on to the other. Later on, these may get transferred back or may become loose wear particles. This paper reports the effects of different experimental conditions on the dry sliding wear behaviour of nickel based alloy (Colmonoy) surface produced by plasma transferred arc (PTA) hardfacing process. The wear test was conducted in a pin on roller wear testing machine, under constant sliding distance of 1 km. Mathematical models were developed to estimate wear rate incorporating rotational speed, applied load and roller hardness using statistical tools such as design of experiments, regression analysis and analysis of variance. It is found that the wear resistance of the PTA hardfaced nickel based alloy (Colmonoy) surface is five times better than that of the substrate (carbon steel).

Evaluation of Dry Sliding Wear Behaviour of Plasma Transferred Arc Hardfaced Stainless Steel

The effects of different experimental conditions on the dry sliding wear behavior of stainless steel surface produced by plasma transferred arc (PTA) hardfacing process were studied. The wear test was conducted in a pinon-roller wear testing machine, at constant sliding distance of 1 km. Mathematical models were developed to estimate wear rate incorporating with rotational speed, applied load and roller hardness using statistical tools such as design of experiments, regression analysis and analysis of variance. It is found that the wear resistance of the PTA hardfaced stainless steel surface is better than that of the carbon steel substrate.

Effect of speed, load and hardness of rollers on dry sliding wear behaviour of PTA hardfaced Stellite surface

AbstractDry sliding wear occurs when two bodies are in sliding contact. During the process of sliding, fragments may be pulled out from one surface and they may stick on to the other. These may subsequantly get transferred back or may become loose wear particles. This paper reports the effects of different experimental conditions on the dry sliding wear behaviour of a cobalt based alloy surface produced by plasma transferred arc hardfacing. The wear test was conducted in a pin on roller wear testing machine, under constant sliding distance of 1 km. Mathematical models were developed to estimate wear rate incorporating rotational speed, applied load and roller hardness using statistical tools such as design of experiments, regression analysis and analysis of variance. It is found that the wear resistance of the plasma transferred arc hardfaced cobalt based alloy surface is three times better than that of the substrate (carbon steel).

The effect of abrasive grain's wear and contact conditions on surface texture in belt finishing

The belt finishing process is a recent manufacturing technique in the field of superfinishing of hard material. Its mechanisms have not yet been fully explained. This paper attempts to make a contribution to the understanding of the wear mechanisms of the abrasive film and its influence on surface roughness. First, the contact conditions between abrasive film and the surface have been analysed and the abrasive film wear has been theoretically modelled. Effective contact duration between grains and machined surface on the one hand, and average contact pressure on the other hand have been introduced as key parameters. Then, the effects of the most influential belt finishing parameters and their interactions on the surface roughness and the material removal have been experimentally investigated. It was revealed the existence of an optimum surface roughness reachable independently of the force and of the roller's hardness. It has also been revealed the existence of an optimum belt finishing duration depending on the feed, the force and on the roller's hardness.

Effects of difference in roller hardness on rolling contact fatigue.

Rollers made from 0.45% carbon steel with hardnesses in the range of 190 to 500 HB were used as test pieces. The rollers were rotated under rolling with sliding conditions. The sum of the initial surface hardnesses of the rollers was made greater than the theoretical oil film thickness, in most cases. Not a single pit occurred on the 190 HB rollers at a Hertzian pressure of 1.30 GPa (132.7 kgf/mm2) when the hardness differences were less than 40 HB units. However, pits occurred at the same Hertzian pressure before 1.5×106 revolutions on the slower rollers (follower) with hardnesses of 220, 250 and 300 HB when these rollers were rotated with the faster rollers of higher hardness, giving hardness differences greater than 10 HB units. By measuring the duration of full EHL conditions, the friction coefficients, etc., it was clearly shown that the reason why an unexpectedly small hardness difference can cause pitting failure is attributed to the insufficient running-in which occurs when the hardness difference is greater than a certain limit.

Limits of Contact Stress Allowable on Rollers Made of Carbon and Alloy Steels (160∼130 HB) and Changes in Contact Surface

Rolling contact fatigue tests were conducted under pure rolling conditions using carbon steel and alloy steel rollers. Hardnesses of pitting rollers were in the range 160 ∼ 100 HB (mating roller hardness was 420 HB in the case of unequal hardness combination). The results obtained are as follows : (1) Theoretical limits of contact stress pmax allowable on the steel rollers are in the range 0.31 ∼ 0.52 HB (kg/mm2) when they are calculated under assumption that pitting does not occur until the reversed shear stress τ2max in rolling contact reaches the endurance limit τw in reversed twisting. (2) In the cases of unequal hardness combination, pitting occurred at Hertzian stresses less than 0.3 HB when the roughness Rmax2 of harder roller was greater than the theoretical oil film thickness hmin. For instance, many pits occurred at a Hertzian stres of 50 kg/mm2 = 0.17 HB when a 300 HB roller with a roughness of 1μm Rmax was combined with a 420 HB roller with a roughness of 3 μm Rmax. (3) However, no pitting occurred at Hertzian stresses greater than the upper limit of theoretical pitting limit pmax = 0.52 HB when Rmax2 < hmin. For instance, no pitting occurred until 107 rotations even when loads corresponding to Hertzian stresses of 113 (=0.71 HB), 140 (=0.61 HB) and 165 (=0.55 HB) kg/mm2 were applied on 160, 230 and 300 HB steel rollers respectively. (4) Appreciable increases in hardness were observed at the subsurface of pitting rollers when the rollers were rotated at Hertzian stresses greater than the theoretical pitting limit 0.52 HB (kg/mm2).