Flap Wheels Research Articles

Wear behaviour of abrasive tools and its effect on surface integrity during polishing superalloy GH4169G with abrasive cloth flap wheels

In polishing nickel-based superalloys, the surface quality and dimensional accuracy of the workpiece are closely related to the wear of the abrasive tools. Over the years, several researchers have studied the wear of grinding wheels or abrasive belts, including the effects of various machining methods, abrasive materials, and machining parameters on the wear of abrasive tools. However, there is not enough research on the wear mechanism of the abrasive cloth flap wheel (ACFW). In this paper, during polishing GH4169G with ACFW, the wear evolution mechanism of ACFW and its effect on the surface integrity of GH4169G were investigated. First, the variations in material removal and ACFW wear amounts during the polishing process were analysed, and the different wear stages were divided based on the polishing ratio. Second, the mic-morphology and surface element distribution of ACFW at different wear stages were investigated using SEM and, EDS, and the wear evolution mechanism of ACFW was analysed. Finally, the effects of ACFW wear on the surface morphology, surface oxidation and microstructure of GH4169G were investigated by SEM, EDS, XRD, and EBSD. The results showed that the primary wear forms of ACFW were stepped fracture, cleavage fracture, blunt, pull-out, and adhesion wear. During the initial wear stage, the proportion of each wear form was relatively balanced. In the medium wear stage, fracture wear was the main wear form. Blunt and adhesive wear were the primary forms of wear during the final wear stage. In addition, with ACFW wear, the surface roughness tend to decrease first and then increase, however, the refinement level of the grains, the intensity of plastic deformation and the intensity of the oxidation reaction gradually increased. This study provides effective guidance for developing more wear-resistant abrasive tools and optimising the grinding and polishing processes.

Features of Machine Grinding of Surfaces with a Flap Wheel

In order to obtain the necessary shape of long panels and sheaths, the aircraft industry successfully uses a complex technology of shaping. Grinding, as an operation in a complex technological process, is provided after the operation of shot-peen forming before hardening. It is designed to ensure that the roughness and final aerodynamic shape of the surface meet the requirements established by the drawing of the part. To implement this technology, a special installation UDF-4 (shot-impact forming unit) was designed and manufactured at the Irkutsk National Research Technical University. The version of this installation was equipped with a CNC system and a revolver stripping head with 4-flap wheels. The possibility of choosing the necessary flap wheels in the process of grinding, depending on the curvature and width of the treated surface, significantly expanded the technological capabilities of the installation. The elastic abrasive flap wheels of a straight profile used in production have proven themselves well both in terms of grinding performance and tool durability. However, practice has shown that due to the complex impact of abrasive petals during contact with the treated surface, a special zone of uneven impact along the length of the contact of the petals is formed during grinding. The results of experimental studies have shown that the roughness of the treated surface is significantly improved when the direction of movement of the flap wheels feed in the contact zone is changed from oncoming to passing. The paper presents experimental data on studies of changes in surface roughness in the contact zone with the abrasive flap wheels during grinding, depending on the processing modes, as well as the results of an experimental study of the quality of the treated surface with counter and passing feed.

Improving the Efficiency of Machine Grinding of Double Curvature Surfaces with a Profiled Flap Wheel

To obtain the desired shape of long panels and sheaths in the aircraft industry, the technology of shot peen forming with subsequent grinding with flap wheels is successfully used. To implement this technology, a special UDF-4 (shot peen forming equipment of the 4th version of modernization) device was designed and manufactured. The last version of this device is equipped with a CNC system and a revolver head with the 4-flap wheels for optimizing the grinding operation. The ability to select the desired flap wheel during the grinding process, depending on the curvature and width of panels or sheaths, has significantly expanded the technological capabilities of this equipment. During grinding with flap wheels of a rectilinear profile, to ensure uniform removal along the cross-section of the part’s curvilinear contour, it is necessary to carry out processing with overlapping previous passages. The need for overlapping passages significantly increases the processing time. At the same time, the calculation of the overlapping width during the changing curvature of the part’s profile is quite a difficult task. This paper presents analytical studies of the use of profiled flap wheels for grinding the part’s surface with a variable radius of transverse curvature, and also proposed the mathematical models for selecting the necessary profiled flap wheels depending on the curvature of the part’s processing surface.

Technique for accelerated tests of samples for wear resistance

A review of the existing methods of accelerated abrasive wear tests is presented. The shortcomings of the technique implemented on an IM-01 installation of the VISKHOM design, as well as the Brinell-Howarth technique for laboratory studies, in which a powder abrasive is used are discussed, e.g., a problem of a uniform distribution of a free-flowing abrasive material over the surface of the contact zone, as well as problems of ensuring the stability of the supply of the abrasive material during the experiment. The goal of the study is to develop a methodology for comparative assessment of the wear resistance, excluding noted shortcomings. The tests were carried out on an M-1 installation using plate specimens 60 × 40 × 3 mm. The abrasive material used was a radial flap wheel 150 – 220 mm in diameter (width 30 mm, bore diameter 30 – 40 mm). The degree of wear was determined by a decrease in the mass of the sample by weighing on a balance with an accuracy of 0.1 mg before and after testing. The test results were considered as a relative wear resistance ε equal to the ratio of the wear resistance of the test specimen to the wear resistance of the reference one. The use of relative wear resistance makes it possible to increase the accuracy of the results obtained due to elimination of the influence of natural changes in external parameters that determine the intensity of wear during the test. The developed installation provides significant shortening of the accelerated comparative test (8 min) compared to 40 min on an IM-1, the structure and grain size of the working fluid, the constancy of the load in the contact zone and the speed of interaction between the sample and the tool being the same. Flap wheels of various grain sizes provide application of the device to a wide range of tasks without preliminary grinding of the samples and necessitate only their preliminary cleaning from slags and large particles after applying wear-resistant coatings.

Improving stripping efficiency of double curvature surface on a setup with turret head

The study was performed to develop a method for selecting a rational profile of a profiled flap wheel for a turret stripping head for cleaning parts with different radius of the transverse curvature. Researchers from the Irkutsk National Research Technical University and Irkutsk Aviation Plant designed and fabricated a special PFS-4 (peen forming setup) unit to implement manufacturing technology of large-scale contour-forming components. The unit is equipped with a CNC system, two movable operating elements, a shot blaster and a turret stripping head with four flap wheels. The paper offers methods and criteria for selecting the profiled flap wheel for stripping the contour-forming surfaces of the components, depending on the curvature radius of the latter. A flap wheel with an optimal curvature radius of 40 m was chosen for analysis, which allows a sufficiently large range of profile curvature of the processed components (from 8 to 40 m) to be covered. Profiled flap wheels 100 and 200 m wide with a flap profile radius of 40 m provided uniform material removal when cleaning the surface with a curvature radius from 8 to 40 m without further overlapping with a finished strip. It was shown that wider profiled flap wheels are necessary to increase stripping efficiency. In this case, a 300 mm wide flap wheel can be used for a component surface area with a transverse curvature radius over 14 m and a 400 mm wheel for surface areas with a curvature radius of over 20 m. Thus, comparing the stripping process of a curved surface by the straight flap wheel revealed that profiled flap wheels significantly expand the workability of the PFS-4 unit turret stripping head.

Features of grinding surfaces of double curvature with cylindrical flap wheels

In the manufacture of the panels and sheaths of outer-forming parts, after milling operations or shot peen forming, grinding the surface with flap wheels is widely used. Surface grinding is often performed with flap wheels, which may have a cylindrical or profiled surface. Since profiled flap wheels are designed to handle surfaces with a specific curvature, cylindrical flap wheels are more universal and more often used. The main task of technological operation of grinding the complex surfaces is to ensure a same removal over the entire part surface. In this paper, an analytical study of the interaction features of the flaps of the cylindrical flap wheel along the width of the flap wheel when grinding the surfaces of double curvature is carried out. The analysis of possibilities for leveling the degree of influence of the flaps of the cylindrical flap wheel on the treated surface by re-overlapping the processing surface to ensure uniformity of grinding is carried out. A variant of grinding the surfaces of outer-forming parts with a cylindrical flap wheel with overlapping passages, which provides uniform treatment of the surface of double curvature, is proposed.

Design technique of highly efficient technological processes for preparation of polymeric composite parts for adhesive bonding

This paper presents the results of technological machining of polymer composite parts with the flexible flap wheels for further adhesive bonding. The peculiarities of polymer composite materials and their application field are revealed. Constructions that use polymer composite material parts are described.The article identifies the process of gluing parts made of polymer composites, as well as features of ensuring the strength of the adhesive joint after mechanical processing of bonded parts.Methodology of modes processing selection and structural-geometric tool parameters for the processing of surface parts under the adhesive bonding is elaborated. Theoretical studies of processing the polymer composite parts with the help of flap wheels are conducted. The surface roughness model is developed. A considerable amount of experimental research has been carried out. The tools for machining and cutting modes are selected. The strength of the glue connection of the details processed by the flap wheels is examined. To compare the durability of the received glue connections and the combinations executed according to the factory technology, the reference surfaces of the samples used at comparative control of quality sanding are investigated. The theoretical and experimental results are compared. Their high convergence is established. The adequacy of the theoretical dependence in compliance with the Fisher criterion is checked. Effective methodology for designing highly efficient technological processes tested in industrial conditions is presented. It allowed to reduce the processing time in more than 2 times, while providing the high strength adhesive bonds.

Formation of shot dimples during shot peening

In the aircraft industry, the technology of shot peen treatment is successfully used for the manufacture of long panels and sheaths, both for forming and finishing hardening. Shot dimples increase the roughness of the treated surface, so after the shot peening, the surface should be grinded with flap wheels to improve the roughness values by partially removing the traces of shot impact. To assess the quality of shot peening as a monitoring indicator, in practice the degree of coverage of shot dimples on the treated surface is used, which is determined by the percentages of the total area of shot dimples to the total area of the considered treatment part. To assign the modes of subsequent grinding with flap wheels, it is necessary to determine the allowance for grinding, which is determined by the value of the maximum depth of the largest dimple within the base area of the treated surface. The paper presents a method of creating a mathematical model to determine the size of dimples in shot peening, as well as modeling and engineering analysis of the shot peening process with the finite element method.

Выбор ширины цилиндрического лепесткового круга для револьверной головки при зачистке крупногабаритных обводообразующих деталей

Выбор ширины цилиндрического лепесткового круга для револьверной головки при зачистке крупногабаритных обводообразующих деталей

To determination of removable material during grinding with flap wheels after shot peen forming

Shot peening are widely used in forming the long panels and sheaths. Due to impact of shot on the processed surface, the specific microgeometry is formed, the characteristic feature of this microgeometry are the numerous dimples of shot with different diameters and depths. The presence of these dimples causes deterioration of the surface roughness parameters. Therefore, after shot peening the mandatory requirement is implementation of grinding with flap wheels for partial removal of the shot dimples, the depth of which in magnitude significantly exceeds the valleys of micro-irregularities formed as a result of previous treatment. The value of the assigned allowance for grinding depends on the requirements for the quality of the surface of the part. As a result of grinding on the treated surface, a new microrelief is formed in the form of a combination of traces of the impact of abrasive grains of flap wheels and the remains of the dimples from shot peening. At the same time, the depth of dimples of shot after grinding is much reater than the values of valleys of the micro-surface formed as a result of impact of the grains of flap wheels. Since the dimples have a spherical shape with a much larger radius of curvature than their depth, they have a special effect on the volume of the removed metal with an increase in the size of the allowance.

Technological Support of Abrasive Manufacturing of Products on a Flexible Basis by Evaluating Performance Indicators

In companies that perform fabrication supported by abrasive processes a challenge of the quality assurance system is development and control of tests for flexible abrasive tools. In this paper, are given the results of technological support of abrasive manufacturing of products on a flexible basis by creating a method and means of its implementation for assessing the quality of a flexible abrasive tool based on performance indicators. A methodology for testing the quality assessment of a flexible abrasive tool has been developed, which is supported by a test bench. An assessment of the stability and objectivity of the obtained indicators when testing a tool from sandpaper, grinding belts and flap wheels is given, and its compliance with the requirements of the standards is shown.

Determination of the allowance for grinding with flap wheels after shot peen forming

Shot peening is widely used in forming long panels and sheaths. Due to the impact of shot on the processed surface, the specific microgeometry is formed, the characteristic feature of this microgeometry is the numerous dimples of shot with different diameters and depths. The presence of these dimples causes deterioration of the surface roughness parameters. Therefore, after shot peening the mandatory requirement is implementation of surface grinding with flap wheels for partial removal of the shot dimples. Allowance for grinding depends on the requirements for the quality of the surface of the part. As a rule, the depth of dimples in magnitude significantly exceeds the valleys of micro-irregularities formed owing to previous treatment. The value of the assigned allowance for grinding depends on the requirements for the quality of the surface of the part. As a result of grinding on the treated surface, a new microrelief is formed in the shape of a combination of traces of the impact of abrasive grains of flap wheels and the remains of the dimples from the shot peening. Since the dimples have a spherical shape with a much larger radius of curvature than their depth, they have a special effect on the amount of metal removed and on the roughness of the treated surface. The paper presents an analytical description of the process of quantitative removal of metal and the formation of roughness during grinding with flap wheels of the surface treated with a shot peening. Based on the results of research, mathematical models are constructed to determine the amount of material removed from the surface treated with shot peening during grinding with flap wheels, and a numerical method for determining the allowance for obtaining the required roughness is proposed.

Methods and approaches to improving the design of flexible backing grinding tools

Grinding with flexible backing grinding tools, such as flap wheels and grinding belts, has found wide application at all stages from roughing to decorative surface finish. At the same time, the performance of traditional factory-built flap wheels and grinding belts in many respects do not meet the expectations of consumers. Among other reasons, this is due to the fact that the designs of flap wheels and grinding belts are based on traditional sandpaper. In turn, the sandpaper is made from abrasive mass which is not sorted by shape and not oriented relative to the backing plate surface. The described situation leads to the fact that a large number of grains does not participate in the cutting process, but on the contrary, have a negative impact on it, because the abrasive particles fall out of the bond, heat and deform the material to be ground without cutting it off. The approaches to improving the design of flexible backing grinding tools are discussed, the issues of their design and manufacture using the abrasive grains with controlled shape and orientation are revealed in the article. The data on the impact of the grain shape and orientation on the cutting ability of grinding belts are given.

Механизация абразивной обработки деталей из полимерных композитных материалов под операцию склеивания

Introduction. The development of the final abrasive processing of parts from polymeric composite materials with the use of the flexible grinding tool is considered. The research objective is to reduce the processing time through displacement of human labour by mechanized work, as well as to improve the treated surface quality. Materials and Methods. The method of surface preparation of parts made of polymeric composite materials (PCM) is used for gluing through the mechanical abrasive treatment with a flexible grinding tool. Research Results. Characteristic features of forming the surface microprofile of GRP parts after treatment with a flexible abrasive tool by hand and mechanical methods are analyzed. Need for mechanization of the given operation is determined and validated. The surface parameters affecting the formation of a quality adhesive bond are described. The design features of a flexible grinding tool and their effect on the formation of surface roughness are considered. Data of the surface microprofile treated by a grit cloth and a flap wheel under various cutting conditions are compared. Discussion and Conclusions. Mechanical processing by flap wheels can replace manual sanding of parts made of polymeric composite materials, drastically reduce the operation time, and improve quality rating of the part surfaces for pasting

Formation of the surface roughness during grinding with flap wheels after shot peening

Shot peening is widely used in forming long panels and sheaths. Due to impact by shot on the processed surface, a specific microgeometry is formed, the characteristic feature of this microgeometry are the numerous dimples as the traces of shot impact with different diameters and depths. A presence of these dimples causes deterioration of the surface roughness parameters. Therefore, after shot peening the mandatory requirement is the implementation of surface grinding with flap wheels for partial removal of the dimples. The size of the assigned allowance for grinding depends on the quality requirements of the part surface. At the same time, the depths of the remaining dimples are determined by the part surface roughness requirements. After grinding, the new surface microgeometry is formed, as a combination of micro-roughness from previous types of processing and the remained dimples in result of shot peening. In this work the microgeometry formation of surface layer of the samples after shot peen forming and subsequent grinding with flap wheels was analysed. The parameters of surface roughness were measured by the method of three-dimensional optical scanning. In the measurement result, the mathematical model of the surface micro-profile formation was formulated, the analytical dependences of the position of the center plane and the arithmetic mean deviation of profile were obtained.

Some considerations regarding finishing by abrasive flap wheels

The diminishing of the surface roughness of a metallic part can be performed by using various finishing methods, polishing by means of abrasive flap wheels being one of them. There are several factors that influence the roughness of surfaces finished by means of abrasive flap wheels. When polishing external cylindrical surfaces by means of abrasive flap wheels, the surface roughness can be changed more easily if the following elements are modified: the peripheral speed of the workpiece and of the abrasive flap wheel, the speed of the longitudinal feed, and the grit size of the abrasive material. Experimental research has allowed for the establishment of power-type functions which highlight the influence exerted by the above-mentioned factors on the size of the surface roughness parameters Ra, RS, RSm, Rku. Analyses of the experimental results have shown that, in the case of the Ra roughness parameter, from among the range of interactions of orders 2 and 3, only the interaction between the rotation speed of the abrasive flap wheel and the speed of the longitudinal feed seems to be significant.

Hand–arm vibration in a group of hand‐operated grinding tools

AbstractVibration acceleration was triaxially and basicentrically measured, and digital‐audio‐tape‐recorded with each axis separately evaluated using both the ANSI S3.34 and ACGIH hand‐arm vibration (HAV) guidelines, for two pairs of pneumatic handheld grinders commonly used in metal fabrication operations including shipyards. Each tool pair consisted of a new and used grinder of the same model, performing the same simulated grinding tasks using new small grinding wheels, carbide burrs, wire brushes, and flap wheels. The results of this limited study showed, primarily, that the HAV standards were not exceeded, but there was a consistent tendency for the acceleration levels to increase between new and used tools, ranging from 11% to 66% on the Z‐axis, 13% to 66% on the Y‐axis, 44% to 58% on the X‐axis, when tasks involved using grinding wheels and carbide burrs (hard implements). The results were mixed when using disposable wire brushes and flap wheels (softer implements). The overall results suggest the need for and implementation of a regular tool vibration monitoring and maintenance program as a primary element to help maintain tool acceleration levels to a minimum. © 2002 Wiley Periodicals, Inc.