Abrasive Disks Research Articles

Experimental study on removal of phenol formaldehyde resin coating from the abrasive disc and preparation of abrasive disc for polishing application

In the automotive and aerospace industry, abrasive products lodge the major portion of the machining applications. Among that, the coated abrasive disc is used for a finishing application. Once the disc is fully consumed, the disc is unused and considered waste. The present work focuses on removing phenol-formaldehyde resin coating, and the fiber backing is reused for the same coated abrasive disc production application as flexible fiber backing. A sandblasting technique removes phenol-formaldehyde resin coating and embedded abrasive grains. During the fiber backing recovery process, the experimental parameters such as abrasive pressure, abrasive type, abrasive size, and orientation of the disc are varied to find out the optimal surface roughness value for reusing the produced coated abrasive discs. The results highlight that the recovered backing has an abrasive size of 120 mesh pressure of 0.20 MPa, an abrasive type of garnet, and a standoff distance of 1 mm. Surface features such as surface roughness and micrographs of the eroded surface are analyzed. Finally, the recovered backing was reused in the coated abrasive disc production, and the performance of the recovered disc was compared with the standard discs. The recovered fiber backing disc product was similar to a standard fresh disc.

Influence of the Duration of Current Pulses on the Roughness in the Combined Processing of Corrosion Steel 12H18N10T

The competitiveness of engineering products in the world market is often determined not only by the quality and operational characteristics of products, but also by the cost saving level and labor intensity of their manufacture. This became especially relevant when a wide range of high-strength and difficult-to-machine construction materials appeared, the processing of which by conventional methods is difficult and ineffective. In recent years, various methods are increasingly used for the shaping of parts made of these materials, the efficiency of which is higher due to the combination of several types of effects on the processing object - combined methods. So, for example, the methods of electrolytic abrasive machining with abrasive disks on a conductive bond have replaced the traditional grinding. One of the particular cases of method implementation is processing with a periodic change in the current pulse direction: direct polarity for electrochemical softening of the processed surface, reverse polarity for restoring the cutting ability of an abrasive tool. Whereanent, the purpose of the work is to establish the effect of dressing current pulses duration on the surface roughness of products made of corrosion-resistant steel of 12H18N10T grade. For laboratory research, a bench was designed and manufactured to simulate the conditions of combined processing. It has been experimentally proved that the smallest roughness value Ra = 0.26 μm is observed at the following values of the current pulse duration: the current pulse of direct polarity duration τst = 1 s and the current pulse of reverse polarity duration τre = 1 s. This allows us to recommend the indicated values in order to ensure high quality of processed surfaces of products made of corrosion-resistant steel 12H18N10T of grade

Effect of stand-off-distance on the performance of TIG cladded TiC-Co coating deposited on Ti-6Al-4V alloy

TiC-Co layer was fabricated on Ti-6Al-4V alloy plate by TIG cladding route using TiC/Co powder blend of equal weight ratio. The distance between the electrode and the work, namely stand-off-distance (SOD), was varied between 4 and 6 mm during the TIG arc scanning, which altered the arc volume and subsequent heat intensity in the powder melt pool. A significant variation in the clad track width and depth was noticed due to the discrepancy in the arc-workpiece interaction area for increasing the SOD. Although almost uniform thickness in the clad layer was obtained, owing to discrepancies in the specific density and thermal conductivity between TiC, Co powder, and Ti-6Al-4V substrate, the constituents of the clad layer were found in-homogenously distributed. Consequently, a marginal diversity in the micro-hardness and wear resistance of the clad layer was recorded for the alteration of SOD conditions. Variation in the concentration of partially melted spherical shaped TiC particles, resolidified dendritic TiC, and other intermediate phases alter the microhardness value in different regions of the clad layer. The results indicated that the wear value or height reduction of the clad specimen was up to 15 times lower than the substrate material when tested against hardened steel. In contrast, the wear value was reduced almost three times when tested against the alumina abrasive disc under different load conditions.

Process optimization and removal of phenol formaldehyde resin coating using mechanical erosion process

Consumption of coated abrasive discs in various automobile and pipe fitting application is increasing, due to its good surface finish. Coated abrasive disc consists of single layer of abrasive grain bonded to a fibre backing. The major portion of the disc is comprised of fibre backing. But the sustainability of the fibre backing is low and is dumped as waste after usage. The present work deals with the removal of resin coating and recovery of fibre backing from the spent coated abrasive discs using physical separation process such as sand blasting technique. Initially, the recovery experiment was carried out based on L16 orthogonal array. The factors and levels chosen for the experiments were erodent pressure (0.2, 0.4, 0.6 and 0.8 MPa), erodent size (36, 60, 80 and 120 grit), disc orientation (30, 45, 60 and 75°) and number of times flexing (5, 10, 15 and 20). The experimental result shows that erodent size and erodent pressure have a major impact on recovery of the fibre backing. The surface structure of the recovered backing was analysed using scanning electron microscopy and optical microscopy. The recovered backing was very much useful for the coated abrasive industry as the flexible backing and support material for abrasive grain coating.

Tribological behaviour of aluminium based hybrid metal matrix composites (Al6061/B4C/ZrO2/SiC)

This research is aimed into the use of stir casting technique to make a variety of reinforced aluminium and non-reinforced hybrid composite materials. Aluminium Metal Matrix reinforced with different volume proportions of ZrO2 (2%, 4% and 6%) and SiC (4%, 8%, 12%) particulate by stir casting techniques. Al6061 and B4C are selected as a base material and ZrO2 and SiC utilized as a reinforced material. Actual density and theoretical density are calculated using the Archimedes principle and the rule of mixtures, respectively, and the porosity is measured in terms of theoretical and actual densities. It can be observed that the density of hybrid composites increases with the addition of reinforcement materials in aluminium matrix. The Pin-on-disc apparatus was used to conduct the wear experiment various sliding distance, sliding speed and applied loads. As results concluded that wear rate of Al6061 + 2%B4C + 6%ZrO2 + 12%SiC hybrid composites are smaller than that of unreinforced aluminium alloys. From the experimental analysis the increasing reinforcements of ZrO2 and SiC particle in aluminium metal matrix decreases the wear rate of prepared hybrid samples. Increasing the load on the abrasive disk reduces the abrasion rate on all models and decreases at a sliding speed of 4.5 m / s and then increases. However, the wear rate decreases with increasing sliding speed, while the depreciation rate increases with increasing sliding distance and load.

Bracket Removal and Enamel Polishing Procedures After Completion of Orthodontic Treatment; A Survey Among Iraqi Orthodontists

Objective: To survey the orthodontic debonding techniques in Iraq and describe the most commonly used methods to remove the brackets and adhesive remnants from the enamel surfaces. 
 Methods: A questionnaire survey consisting of 9 questions about general information of the participants (gender, work location, duration of practicing orthodontics), bracket debonding methods, and instruments used was electronically sent to Iraqi orthodontists. 
 Results: Overall, 91 orthodontists responded. 67% of participants found enamel damage after bracket removal. The most commonly used pliers for bracket debonding were bracket removal pliers (73.6%) and ligature cutters (23.1%). For adhesive removal, high-speed tungsten carbide burs were the most widely used technique for adhesive removal, followed by low-speed carbide burs and low-speed abrasive discs, respectively. The most frequently used instruments for polishing after debonding were rubber cups with pumice (40.65%). 
 Conclusions: In the present survey, it is shown that bracket debonding pliers are the most commonly used pliers for bracket removal. High-speed tungsten carbide bur is the most utilized method for adhesive removal, rubber cup together with pumice is the most commonly used technique for tooth polishing.

Analysis of the Possibility of Using New Types of Protective Coatings and Abrasion-Resistant Linings under the Operating Conditions of the Spiral Classifier at KGHM Polska Miedź S.A. Ore Concentration Plant

A study was carried out to select the appropriate coatings for corrosion protection of the spiral classifier working at KGHM Polska Miedź S.A. Ore Concentration Plant. The abrasion resistance of selected protective coatings and wear-resistant linings was investigated using a DT-523 rotary abrasion tester with Taber CS-10 rubber abrasive discs. The average weight loss of the coatings after a cycle of 2000 revolutions was determined. Tests of protective coatings using the electrochemical impedance spectroscopy (EIS) technique were carried out to determine the suitability of coatings in the highly saline environment of the aqueous suspension of ground copper ore. During the measurements, changes in resistance, polarising current and capacitance were determined as a function of time for the tested coatings. The linings selected on the basis of laboratory tests were also tested under industrial conditions. Their degrees of wear were characterised. The results obtained indicated the highest abrasion resistance of materials from the polyolefin group (polyethylenes), where the average weight loss did not exceed 5 g/dm2. In the case of protective coatings, the highest durability was demonstrated by coatings with additives of ceramic aggregates, phenol-epoxy, and an elastomeric coating based on polyurea, whose average weight loss during the test cycle did not exceed 19 g/dm2. EIS measurements showed that the tested coatings were resistant to the aggressive environment of the feedstock. Tests under cathodic polarisation conditions of the samples at a potential below the protection potential showed that they were resistant to a highly saline environment and were also resistant to its alkalinisation resulting from the application of cathodic protection, which will be used to protect the classifier together with protective coatings. Tests carried out under industrial conditions using wear-resistant linings made of plastics have made it possible to analyse the mechanism and degree of wear of the various materials during the operation of the classifier. Measurements of lining wear were made in relation to baseline volumes. Polyurethane, a polymer lining based on MDI and PTMG, and those made of ultra-high-molecular-weight polyethylene with anti-stick additives showed the lowest wear rates.

Effect of brushing on surface roughness, fluoride release, and biofilm formation with different tooth-colored materials

Background/purposeTooth brushing, material mechanical ageing procedure, is the most effective way in removing biofilm. The purpose of this study was to investigate the surface roughness, fluoride-release, and S. mutans biofilm formation on various tooth-colored restorative materials before and after brushing. Materials and methodsDiscs of materials, a nanocomposite (Filtek Z350XT; CO), a giomer (Beautifil II; GIOMER), a resin-modified glass-ionomer material (Fuji II LC; RMGI), and a conventional glass-ionomer material (Fuji IX GP Extra; GI), were prepared, polished with abrasive discs (SofLex), and divided into brushed and not brushed groups. The surface roughness of specimens was observed using a contact profilometer, fluoride-release was measured using a fluoride-specific ion electrode, and S. mutans biofilm formation, biovolume and live/dead cells, was observed under a confocal laser scanning microscope. ResultsHigher roughness was observed on GI and RMGI than on CO and GIOMER. Brushing had no effect on the roughness. The fluoride-release of GI and RMGI was higher than that of GIOMER. The fluoride-release decreased after brushing in all materials. The biovolume of S. mutans was not significantly different between GIOMER, RMGI and GI, while CO showed the highest. Brushing resulted in a higher biovolume for all materials, except CO, which showed no change. After brushing, all the tested materials demonstrated identical biovolumes. There were no significant differences in live/dead cells among all groups. ConclusionBrushing demonstrated a negative effect on the fluoride-release and biovolume of S. mutans biofilms for all tested materials except nanocomposites.

CMP Pad Conditioning and Applications to Type 1 Impregnated Felt Polishing Pads

Pad conditioning is the process of “dressing” the surface of the polishing pad, generally with a highly engineered diamond abrasive disc. Conditioning not only refreshes the pad surface, the cutting characteristics of the conditioner determine the structure of the asperities that are in contact with the wafer. By tuning the cutting characteristics of the conditioner, polish performance can be manipulated over a wide range. With the most advanced pads, specific conditioning protocols are typically required to obtain the designed performance. Optimization of these protocols is enabled by an understanding of the pad surface statistics.Figure 1 illustrates the two types of polishing pads that will be compared in this talk. Suba 800 is an example of a Type 1 pad. Type 1 pads consist of a “non-woven” needled polyester felt impregnated with polyurethane. The pores in a Type 1 pad are formed from the spaces between the impregnated fibers and have a length scale of 100s of microns. The pores in a Type 1 pad tend to be interconnected. VP5000 is a Type 3 pad. Type 3 pads consist of discrete pores in a matrix of polyurethane. The matrix properties can be varied over a wide range and pore sizes range from single to 10s of microns. Type 3 pads should be isotropic in terms of their physical property and porosity distribution. Type 3 pads typically exhibit Shore D hardness in the range of 20-70. Type 1 pads are measured on softer hardness scales or in terms of compressibility.Pad conditioning of Type 3 pads in semiconductor wafer CMP is at a technically mature stage, and the knowledge base can be directly applied to substrate polishing with Type 1 pads. The decoupled Gaussian-Exponential model which has been successfully used in Type 3 pads can be directly applied to Type 1 pads. As Figure 2 illustrates, Type 1 pads exhibit an exponential porosity signature, but with a decay length about an order of magnitude larger than a typical Type 3 pad, consistent with the difference in length scales of the pores of the two pad types. The core of the distribution (accounting for most of the total surface) can be modeled as a Gaussian.Figure 3 provides examples of both Suba 400 and Suba 800 and differences in both the intrinsic porosity (exponential decay constant, Eτ) and Gaussian core width are evident. At least part of the difference in the porosity signature is due to the Suba 800 receiving a double impregnation of polyurethane, compared to a single impregnation for Suba 400, resulting in a comparatively shallower pore structure. The difference in the Gaussian core width is most likely the result of a different buffing process or media used to impart a surface finish at the factory.Figure 4 illustrates the range of texture that can be developed on the DuPont Suba 800 impregnated felt pad, one of the Type 1 pads most widely used in substrate polishing applications. As the figure illustrates, the hwhm of the Gaussian core can be driven from about 10 to 50 µm, while maintaining the deep background porosity that characterizes this pad. The ability to drive the texture into rougher and smoother regimes, compared to a new pad, implies a potential to drive the substrate process into previously unattainable performance spaces. Initial feedback from the field indicates that smoother pad surfaces can contribute to improved substrate surface finish. Rougher surfaces may contribute to improved throughput through polish rate increase.Figure 5 illustrates how key pad roughness metrics of Suba 800 are correlated with a basic conditioner diamond design parameter. Most roughness measurements are highly correlated, although one of the most widely used roughness parameters, the average roughness Ra, does not correlate well at all in this case. This is an excellent example where pad height distribution modeling provides critical insight into the drivers of the textural changes that effect polish performance, and how that performance might be manipulated through conditioning design.Signatures of surface textural degradation from the stress of polishing and accumulation of debris can be observed on Type 1 pad surfaces. It is well known that restoration of the pad surface structure through conditioning is a primary mechanism of stability in Type 3 pads. Data from the field indicates improvements in process performance and consumable life with Type 1 pads when conditioning has been implemented versus processes with no pad conditioning. The examples given here will be expanded upon and additional applications will be discussed. Figure 1

Влияние отношения высот кругов в комбинированном инструменте на шероховатость шлифованной поверхности

The impact of the height ratio of fine-grain abrasive disks and coarse grinding ones included in a combined tool upon roughness of the surface ground is considered. There are drawn dependence diagrams of the arithmetic mean deviation of the ground surface profile in the function of independent factors of the process. On the basis of the multi-factor experiment carried out there is defined a ratio of heights of grinding disks mentioned ensuring a minimum value of the micro-geometry of the surface worked.

Effect of Short-Term Low-Temperature Austempering on the Microstructure and Abrasive Wear of Medium-Carbon Low-Alloy Steel

Nano-bainitic steels have attracted great attention for good wear resistance. In this research, a medium-carbon low-alloyed steel was austempered at a low temperature close to its martensite-start temperature for various times to obtain mixed microstructure of nano-bainite, martensite and retained austenite. The austempered samples were characterised comprehensively by field-emission SEM and quantitative XRD. Its two-body abrasive wear property was evaluated by sliding on a SiC abrasive disc. The results revealed the formation of initial nano-width carbide-free bainitic ferrite (BF) after austempering by 10 min, whereas the BF size and amount both increased with the austempering time. The austempered samples exhibited wear coefficients lower than the quenched martensitic sample by up to 50%. SEM and TEM observations showed wear mechanisms of micro-cutting and ploughing deformation, including the formation of a nano-laminate top layer and bending deformation in the subsurface multiphase microstructure. The decreased wear loss was attributed to the role of retained austenite in the increased plasticity.Graphic abstract

Повышение точности и уравновешенности шлифовальных кругов различной твердости

It is shown that the most efficient methods of abrasive disk quality improvement in the matter of abrasive disk accuracy and balance increase are vibro-mixing, formation in rotating press mold, burning between refractory plates and machining application with diamond tools.

Investigation of TIG Cladding of NiTi Wire on Substrate 304L to Study the Effect of Applied Current on Microstructure and Mechanical Properties

NiTi wire of 1 mm diameter was deposited on austenitic stainless steel (304L) for surface property modification using the tungsten inert gas (TIG) cladding process. The study shows that the microstructure and mechanical properties of the NiTi cladding are governed by TIG process parameters, namely TIG current. The micro-hardness of the NiTi clad region has improved 4.7 times compared to the substrate material 304L. The wear resistance of the clad layer against the abrasive disc (Al2O3) shows up to 6 times improvement than the substrate material austenitic stainless steel 304L. The presence of Ti-rich (Ni,Fe)Ti, NiTiFeCr and intermetallics, responsible for high hardness and high wear resistance, has been observed in the clad surface, which have been confirmed by the XRD and EDS analysis. The optical and FESEM micrographs of the clad, intermediate and substrate metals have been analysed, and the influence of TIG current on microstructure and mechanical properties has been investigated. With the improved significant results, NiTi clad specimens can be used as a cutting and grinding tool for industrial applications.

INFLUENCE OF THE COPPER AND STEEL SURFACES’ ROUGHNESS ON SURFACE ENERGY AND WETTABILITY

This article aims at solving the fundamental problem of thermal physics. This problem includes controlling small volumes of liquids on the heat exchange surfaces of special devices (for example, thermosyphons and heat pipes) working in a closed evaporative-condensation cycle. The authors analyze the effect of roughness on surface energy and wettability of different textures on typical heat exchange surfaces made of copper and steel prepared for operation by mechanical (abrasive) processing. Six textures were created on the copper and steel surfaces using a grinding and polishing machine. The roughness of the textures was evaluated based on the analysis of three-dimensional roughness characteristics (amplitude and hybrid). The surface wettability was studied on the experimental setup with the shadow method. The surface free energy of abrasively processed surfaces was determined by the Owens—Wendt—Rabel—Kaelble method. The results show the necessity of using at least one three-dimensional amplitude and hybrid characteristics to evaluate the textures. The authors have determined the conditions for the formation of Gaussian and sinusoidal textures. A significant increase in surface area is achieved when copper and steel are processed with the abrasive discs with an average grit size of up to 100 μm. This increase is up to 7% for copper and up to 2.7%. After abrasive processing of copper and steel surfaces, the proportion of the polar component in their total surface energy changes. This is a consequence of changes in dipole interactions and hydrogen bonds between atoms.

Determination of precision conditions for measuring relative values in mechanical tests of various materials

The problem of insufficient detail of the requirements for the developed and certified measurement methods used in mechanical testing of various materials is considered. The compatibility of the requirements of metrological support for the results of quantitative chemical analysis and indirect results of mechanical tests for the wear resistance of materials when rubbing against a fixed abrasive is relevant. To ensure the accuracy of measurements, it is proposed to use the grain size of the abrasive material and the rotation speed of the abrasive disk as variable factors. In order to establish the requirements for the metrological characteristics of materials during mechanical tests, in particular, when determining the relative wear resistance, the conditions for precision measurements are justified. The results of a multi-stage experiment-testing of materials for wear resistance with the use of various research and consumables, measuring instruments and testing equipment are presented. The conditions for the organization of the experiment in the case of determining other relative mechanical characteristics of the materials under study for establishing precision indicators in the development of methods of mechanical tests for abrasive wear are proposed and justified. The application of the obtained results will allow developers of mechanical testing methods to establish metrological characteristics of materials in compliance with all the requirements of the State System for Ensuring the Uniformity of Measurements of the Russian Federation.

Design and development of compact Foxtail millet deshelling machine

Abstract Millets are cereal crops that fall under the category of small seeded grasses. Millets are the basic cereals in India and eaten by a majority of the rural community, and constitute around 25 percent of the total food grain production in India. Millets are among the most nutritious food grains available in India and are rich source of vitamins, minerals, calcium, fiber and also has low glycemic index. Millets contain a dry external cover called husk/ shell. Removal of the husk is called De-husking/ De-shelling. Manually Deshelling is quite difficult and also requires lot of human effort and there will be damage to the seeds. To overcome these difficulties, machines have been developed. However, the existing/conventional machines have the drawbacks such as larger in size and capital intensive. The maximum number of farmers involved in millet cultivation are small land holding farmers producing millets in small quantity and the existing machines are not suitable for small quantity processing. Hence an attempt is made to overcome the difficulties of small farmers, by developing a small machine suitable for multiple millets. The specification developed included important parameters like Method of Deshelling, type of deshelling, weight of Millets for each batch, diameter of abrasive disc, motor power, distance between the abrasive discs, total weight of the system, operating speed. Different product concepts were developed to meet the developed specifications and the most suitable one was selected. The selected concept consisted of different subsystems like the deshelling mechanism, power system and frame. All these subsystems were synthesized and designed successfully to meet the requirements. The complete fabrication of all the subsystems and final assembly was carried out. The developed compact foxtail millet deshelling machine has been tested for its working and found to be satisfactory.

Dimensional Analysis of Workpieces Machined Using Prototype Machine Tool Integrating 3D Scanning, Milling and Shaped Grinding.

In the literature, there are a small number of publications regarding the construction and application of machine tools that integrate several machining operations. Additionally, solutions that allow for such integration for complex operations, such as the machining of shape surfaces with complex contours, are relatively rare. The authors of this article carried out dimensional analysis of workpieces machined using a prototype Computerized Numerical Control (CNC) machine tool that integrates the possibilities of 3D scanning, milling operations in three axes, and grinding operations using abrasive discs. The general description of this machine tool with developed methodology and the most interesting results obtained during the experimental studies are given. For a comparative analysis of the influence of the machining method on the geometric accuracy of the test pieces, an Analysis of Variance (ANOVA) was carried out. The obtained results show that for four considered features (deviations of flatness, vertical parallelism, opening dimensions, and opening cylindricality), no statistically significant differences were detected. For the evaluation criteria, the probability level p exceeded the assumed confidence level α = 0.05 and ranged from p = 0.737167 to p = 0.076764. However, such differences were found for two others—a dimensional deviation between flat surfaces (p = 0.010467) and horizontal parallelism deviation (p = 0.0)—as well as for the quality of the machined surface defined by four surface texture parameters: Ra (p = 0.831797), Rt (p = 0.759636), Rq (p = 0.867222), and Rz (p = 0.651896). The information obtained by the ANOVA will be useful for the elimination the weaknesses of the prototype machine tool, further analysis of technological strategies, and to find possible benefits of integrating machining operations.

Open-Source Grinding Machine for Compression Screw Manufacturing

Some of the most promising distributed recycling and additive manufacturing (DRAM) technical systems use fused particle fabrication (FPF) or fused granular fabrication (FGF), where compression screws force post-consumer waste plastic through a heated nozzle for direct 3D printing. To assist the technical evolution of these systems, this study provided the details of an invention for a low-cost, easily replicable open-source grinding machine for compression screw manufacturing. The system itself can be largely fabricated using FPF/FGF following the self-replicating rapid prototyper (RepRap) methodology. This grinding machine can be made from a cordless cut-off grinder and < $155 in parts. The new invention is demonstrated to be able to cut custom screws with variable (i) channel depths, (ii) screw diameters, (iii) screw lengths, (iv) pitches, (v) abrasive disk thicknesses, (vi) handedness of the screws, (vii) and materials (three types of steel tested: 1045 steel, 1144 steel, and 416 stainless steel). The results show that the device is more than capable of replicating commercial screws as well as providing makers with a much greater flexibility to make custom screws. This invention enables the DRAM toolchain to become even more self-sufficient, which assists the goals of the circular economy.

Process optimization for recovery of fiber backing from coated abrasive disks

Coated abrasive disks are supported by vulcanized fiber backing. The disks are normally used for various material removal processes, at the end of which the remaining backing is dumped as waste. Being vulcanized fiber, it is difficult to dispose of. It is non-biodegradable and causes environmental pollution. The fiber backing itself is costly and will be of value, if recovered. In this research work, chemical separation technique is opted to remove the available resin and grains from the fiber backing. The present work highlights and reduces pollution by addressing recovery of fiber backing from used fiber disks. Coated abrasive disks of grit sizes 36, 60, and 120 were chosen for the optimization process. The process parameters such as normality (2.5, 3, and 3.5 N), solution quantity (300, 400, and 500 ml), number of flexing cycles (0, 5, and 10), and immersion time (8, 10, and 12 h) were selected for the fiber recovery. Taguchi method was employed for the optimization process. Recovery duration was selected as a response parameter. Signal to noise (S/N) ratio was calculated from the experimental results, to optimize the quality and recovery duration of the fiber backing. The results indicate that increase in normality, solution quantity, and immersion time facilitate quick and easy recovery of the fiber backing. Apart from that, the disks of medium and fine grits are possible to reuse compared with coarser grit. The effectiveness of resin removal from the backing, is traced through optical microscopy.

Abrasive Disc Performance in Dry-Cutting of Medium-Carbon Steel

Abrasive-cutting processes are widely used to obtain semi-finished products from metal bars, slabs, or tubes. Thus, the abrasive cutting-off process is applied when requiring precision cutting and productivity at a moderate price. Cut-off tools are discs composed of small abrasive particles embedded in a bonding material, called the binder. This work aims to compare the cutting performance of discs with different composition, in dry cutting of steel bars. To do that, disc wear was measured and disc final topography was digitalized in order to determine both disc surface wear patterns and if the abrasive particles bonding into the binder matrix was affected. In addition, X-Ray inspection gave information about the abrasive grit-binder bonding. Therefore, the method here presented allows identifying discs with a superior abrasive-cutting capability, by combining profilometry and tomography to define micrometrical aspects, grit size, and binder matrix structure. Results led to the conclusion that discs with high grit size and protrusion, high grit retention by bond material, and closer mesh of fiberglass matrix binder were the optimal solution.