Circular Diamond Research Articles

Experimental and statistical analysis of cutting force acting on diamond sawblade in sawing of granitic rocks

In this study, sawability analyses of granitic rocks were carried out using segmented circular diamond sawblades. In the experimentations, a computer controlled cutting machine was used and the experiments were performed with the same-direction cutting mode. Effects and contribution of each operating variable (the peripheral speed, workpiece traverse speed, cutting depth and flowrate of cooling fluid) on the cutting force were determined and cutting forces were correlated with rock properties. Moreover, models were built depending on the operating variables and the rock properties (physico-mechanical and mineralogical properties) for the estimation of cutting force. The results indicated that the higher cutting forces were obtained for higher cutting depth and traverse speed and for lower peripheral speed and flowrate of cooling fluid. The most significant operating variable affecting the cutting force was determined as cutting depth. It was concluded that rather than the physico-mechanical properties, mineralogical properties (such as quarts, plagioclase and feldspar content) is the dominant rock properties affecting the cutting force. Results also revealed that the predictive models derived from operating variables and materials properties have high potentials for practical applications.

Development of Predictive Models for the Specific Energy of Circular Diamond Sawblades in the Sawing of Granitic Rocks

This paper presents an experimental study on the sawing of granitic rocks by circular diamond sawblades. The influence of the operating variables and rock properties on the specific energy were initially investigated and analyzed. To determine the most significant operating variables and rock properties influencing the specific energy, statistical analyses were then employed and the models were built for the estimation of specific energy depending on the operating variables and the rock properties. Moreover, the derived models were validated through statistical tests such as the determination coefficient, t-test, F-test, and residuals. The results indicated that the specific energy decreased with the decreasing of peripheral speed and the increasing of traverse speed, cutting depth, and flow rate of cooling fluid, respectively. It was concluded that, rather than the physico-mechanical properties, the mineralogical properties were the dominant rock properties affecting the specific energy. Additionally, the peripheral speed was statistically determined as the most significant operating variable affecting the specific energy. The peripheral speed was followed by the cutting depth, traverse speed, and flow rate of cooling fluid with respect to their level of significance on the specific energy. Furthermore, the model results revealed that the developed models have high potentials as a guidance for practical applications.

Prediction of specific cutting energy for large diameter circular saws during natural stone cutting

Statistical methods re-utilized for the prediction of specific cutting energy values (SEcut) based on the operational variables of block cutters and rock properties. Performance measurements of seven different types of block cutters were applied to six different carbonate rocks and three stone processing plants. Energy consumption of large diameter circular diamond saw block cutters was measured and recorded for a number of sawblade diameters during the cutting process by means of a portable power analyzer. Additionally, rock samples were collected from stone processing plants for laboratory tests. Uniaxial compressive strength, bending strength, Brazilian tensile strength, point load strength, Shore hardness test, Schmidt hammer hardness test, seismic velocity, water absorption at atmospheric pressure, apparent density, open porosity, sawblade diameter, and depth of cut values were used as input parameters in the analysis for the prediction of SEcut. The reliability of the developed model was tested with statistical methods. The SEcut values for carbonate rocks in the stone cutting process can be predicted successfully for large diameter circular saws in natural stone processing by using the model developed here.

Optimum cutting speed of block-cutting machines in natural stones for energy saving

Energy consumption of block-cutting machines represents a major cost item in the processing of travertines and other natural stones. Therefore, determining the optimum sawing conditions for a particular stone is of major importance in the natural stone-processing industry. An experimental study was carried out utilizing a fully instrumented block-cutter to investigate the sawing performances of five different types of travertine blocks during cutting with a circular diamond saw. The sawing tests were performed in the down-cutting mode. Performance measurements were determined by measuring the cutting speed and energy consumption. Then, specific energy was determined. The one main cutting parameter, cutting speed, was varied in the investigation of optimum cutting performance. Furthermore, some physico-mechanical properties of the travertine blocks were determined in the laboratory. As a result, it is found that the energy consumption (specific energy) of block cutting machines is highly affected by cutting speed. It is determined that specific energy value usually decreases when cutting speed increases. When the cutting speed is higher than the determined value, the diamond saw can become stuck in the travertine block; this situation can be a problem for the block-cutting machine. As a result, the optimum cutting speed obtained for the travertine mines examined is approximately 1.5–2.0 m/min.

An investigation on the effect of diamond concentration and matrix material composition in the circular sawing process of granites

In the process of natural stone cutting, segmented circular diamond saw blades are widely used in the sawing process of granites. Generally, copper, cobalt, or a combination of these is used as the matrix material. The diamond particle used in segments is added to the matrix material in certain rates and sizes. In this article, the effect of tungsten, cobalt, copper, and tin elements, which are added to the matrix material, on the cutting performance was studied. In addition, in order to study the effect of diamond concentration, the segments with different diamond concentration were manufactured. Using these segments, cutting experiments for granite, which are known as natural hard stones, are conducted. In the cutting experiments, peripheral speed of the cutting disc, cutting speed, and depth cut were taken as constant. After the experiments, cutting forces, power consumption, and specific energy changes for each segment were determined. On the other hand, the status of damage and wear for the surfaces of each segment during the cutting process was evaluated in terms of segment performances. According to the results, an increase in diamond concentration results in a lower cutting force and power consumption and also causes a lower specific wear of the segment.

Investigation of the Effect of Axial Cutting Force on Circular Diamond Sawblade Used in Marble Cutting Process

In the marble cutting process, generally, normal and tangential forces are taken into account. However, the axial forces (F z ) on the cutting disc affect the economic life of the disc and segment wear significantly. In this study, the effect of the axial forces on discs, which are used in the marble cutting process, on cutting performance was investigated. Therefore, by taking into account different cutting parameters (peripheral speed, traverse speed and depth of cut), the axial forces on circular saw were measured by means of a dynamometer. In addition to this, using a laser displacement meter, the amount of axial deviation for each cutting parameter in the course of cutting was determined. According to the experimental results obtained, the increase of traverse speed and depth of cut also significantly increases the axial deviation of the cutting disc. Moreover, it is observed that traverse speed and depth of cut have an impact on axial deviation of the saw at the initial moment when the saw starts to cut.

Optimization of the arrangement of fiber laser array in beam coherent combining

Based on the expanding of the fundamental mode of a step-index fiber in terms of Laguerre–Gaussian modes, the accurate expression for the beam propagation of a fiber laser in free space is obtained. Thereby, the coherent combining beam of three fiber laser arrays including circular arrangement, square arrangement, and diamond arrangement are numerically analyzed. The study shows that all the beams gradually concentrate centrally on the propagation axis and the highest far-field peak intensity can be obtained by using the circular arrangement. Meanwhile, the far-field intensity of the circular arrangement by using the Laguerre–Gaussian approximation is also compared with that by using the pure Gaussian approximation, which indicates that the pure Gaussian approximation will induce much error in the far-field intensity. Finally, the influence of the radius of a circular fiber laser array on the far-field intensity is studied, of which the result shows that the far-field intensity decreases with increasing radius. Therefore, the fiber laser elements are suggested to be placed as close as possible.

Correlation of specific energy of cutting saws and drilling bits with rock brittleness and destruction energy

The focus of this study is to statistically evaluate the correlations between brittleness, destruction specific energy (SE des), and both cut-ability and drillability using the optimum data obtained from the experimental works. Applying regression analyses, the predictive models of cutting specific energy (SE cut) and the drilling specific energy (SE drill) were developed based on the rock brittleness and rock destruction energy data. The models were verified by statistical tests and found to be reliable on being used in practical situations. Good linear, polynomial and exponential relationships between SE cut of circular diamond saw blades and the brittleness B 1 (the ratio of compressive strength to tensile strength), B 2 (the ratio of compressive strength minus tensile strength) and B 3 (compressive strength multiple tensile strength divided by two) were found. There are no correlations between SE drill of polycrystalline diamond compact (PDC) core bits, impregnated diamond both core and non-core bits and brittleness values. The newly defined destruction specific energy (SE des) was estimated from the area (integral) under stress–strain envelope in unconfined compression test. This method provides a better understanding of the relationships between SE cut, SE drill, drilling and cutting rate, and the main mechanical rock character. SE des was found to be directly related to brittleness of B 1, B 2 and B 3. Each method of measuring brittleness has its own usage in rock processing depending on practical utility.

Diamond milling of micro-optics

A diamond mill (a tiny end mill) can cut aspheric lenses and mirrors with diameters smaller than 0.5 mm. The cutting tool has a two-dimensional shape and is spun about the axis of the surface to be cut. As the spinning tool is plunged into the substrate, it cuts a radially symmetric surface to sub-micron accuracies. Commercially available circular diamond tools can be modified to aspheric shapes using a focused ion beam. Fabrication examples will be presented and the optical performance of an array of micro-lenses will be described.

The state of concrete on the upstream face of the Ust’-Ilimskaya Hydropower Plant

An integrated investigation of the state of concrete of the upstream face of the Ust’-Ilimskaya HPP was carried out in 2004 – 2005 by means of control drilling and testing the concrete core samples. Holes were drilled in the upstream face concrete near the joints between sections and at the depth of elevation 220, 235, and 250 in sections 33, 34, 35, 42, 43, 49, and 50; the total length of the holes was more than 150 m. Furthermore, a network of holes of total length 127 m was drilled at mark 235 in section 30, which intersected a constantly seeping crack. The tests of the concrete core samples included the determination of the strength of concrete, its density and pore structure, the degree of hydration of cement, and the content of free CaO and Na2O in cement stone. The end faces of samples for strength tests were treated by a circular diamond saw to obtain cylindrical samples with the ratio d:h = 1:2. The density of hydrotechnical concrete mostly operating in the water-saturated state was determined on samples with the maximum water absorption [1].

Effect of cutting mode on the sawability of granites using segmented circular diamond sawblade

Wear and energy consumption are the two main cost items in the processing of natural stones using segmented circular diamond sawblades. Hence, there are many benefits to be gained in understanding the various aspects of this process. The present study was undertaken to examine the effect of cutting mode on the sawing performance of some selected granites. Two cutting modes, up-cutting and down-cutting, were employed in the experiments. Six different types of granites which have substantial market demand were used as workpiece materials for the sawing experiments. Experimental tests were conducted on a fully instrumented experimental block-cutter. Considering the specific wear rate of the sawblade and specific energy of cutting as the main performance criteria of the process, the variations in specific wear rate of the sawblade and specific energy consumption of cutting for each employed cutting mode were analyzed. Valid for all tested granite types, the experimental results showed that specific wear rate and specific energy values obtained in the up-cutting mode are less than those of the down-cutting mode, indicating a more efficient cutting process. The obtained results show that high values of specific energy are associated with high specific wear rates of the sawblade. Also, a stepwise linear multiple regression analysis was performed in order to be able to determine the combined effect of the most dominant mineralogical and physico-mechanical rock properties on specific wear rate and specific energy for both up-cutting and down-cutting modes. The statistical analysis indicated the bending strength and plagioclase percent as the most dominant rock parameters in the prediction of specific wear rate and specific energy of cutting.

Performance Prediction of Circular Diamond Saws from Mechanical Rock Properties in Cutting Carbonate Rocks

Performance Prediction of Circular Diamond Saws from Mechanical Rock Properties in Cutting Carbonate Rocks

Specific Energy Prediction for Circular Diamond Saw in Cutting Different Types of Rocks Using Multivariable Linear Regression Analysis

Circular diamond saw performance is affected by a variety of factors. The principal factors requiring consideration when predicting cutting rates are the type and operating features of a diamond saw and the rock characteristics. The laboratory experimental tests are carried out on three groups of rocks (16 types) cut with the help of three types of diamond disk saws with different feed rates and cutting depths at constant peripheral velocity. The quantitative determinations of a wide range of textural, mechanical, and intact properties of rocks are also made. The relationship between the specific cutting energy SE cut of the sawblade operating parameters and rock properties is established. Applying multivariable linear regression analysis, the predictive model of SE cut is developed based on the rock property data. Models verified by statistical tests prove their practical validity.

Wear characteristics of circular diamond saws in the cutting of different hard abrasive rocks

Circular diamond saw of wear is affected by a range of factors. However, the principal factors that require consideration in predicting wear rates are the type of diamond saw, the saw operating parameters and the characteristics of the cut rock. A single rock property index is not a sufficient basis for predicting wear performance. A variety of ten types of rocks were cut in the laboratory with two types of circular diamond saw using a fully instrumented cutting rig at different feed rates, depths of cut and at constant peripheral speed. Quantitative determinations of a wide range of textural, mechanical and intact properties of the rocks were also made. Wear (weight loss and height loss) of saw were measured after a series of test in each rock type. The wear of saws can take many forms, however, the most common wear mechanism operating on saws during the rock cutting is abrasion. Impact loading and impact fatigue also accelerates the wear of saws. The analysis indicated that the statistical model for the rock saws have potential for practical application. The application of multiple regression analysis to diamond saw performance is novel and the technique shows promise for the prediction of saw wear in specific rock types. The ability of the technique to provide a mathematical characterization of the performance of new cutting saws in the specific rocks may prove to value to saw manufacturers and users.

Performance characteristics of circular diamond saws in cutting different types of rocks

Sawing or cutting cost is controlled to a large extent by the sawing or cutting rate, which is heavily influenced by the performance of the saw. The performance characteristics of the saws are affected by a range of factors. However, the principal factors that require consideration in predicting sawing rates are the type of diamond saw, the saw operating parameters and the properties of the sawn rock. A variety of five groups of rocks (16 types) were cut using three types of diamond circular saws at different feed rates (0.2, 0.4, 0.6, 0.8, 1.0 m/min) and depths of cut (10, 30, 50, 70, 90 mm) and at a constant peripheral speed (65 m/s). A wide range of textural, mechanical, physical and intact properties of the rocks were quantitatively determined. Operating parameters of the diamond saws were continuously monitored during the cutting trials. Generally, down cutting method was applied in the experiments. The effects of the operating and rock parameters on the performance of the diamond saws were examined and relations between the cutting variables are described. Correlations between textural, physical and mechanical properties of the rocks with specific cutting energy of the saw are also highlighted.

Investigation of Cutting Forces in Concrete Sawing Process

Diamond saw blades are widely used in cutting concrete materials in civil engineering 6 industry. Concrete is a kind of difficult-to-cut composite material. The cutting forces in concrete 7 cutting processes by single-diamond tools and sawing processes by circular diamond blade were 8 investigated in this paper to provide basic information for properly selecting sawing conditions and 9 optimizing blade structure. The signals of cutting forces under different conditions were acquired 10 and analyzed. The results show that the properties of composition in asphalt concrete have 11 significant influence on instantaneous cutting forces. The effect of cutting speed on cutting forces is 12 smaller than feed speed and depth of cut in concrete sawing processes. 13

반도체 웨이퍼를 위한 새로운 다이싱 방법

The general dicing process cuts a semiconductor wafer to lengthwise and crosswise direction by using a rotating circular diamond blade. But products with inferior quality are produced under the influence of several parameters in dicing process such as blade, wafer, cutting water and cutting conditions. Moreover we can not apply this dicing method to GaN wafer, because the GaN wafer is harder than the other wafer such as Si02, GaAs, GaAsP, and AIGaAs. In order to overcome this problem, development of a new dicing process and determination of dicing parameters are necessary. This paper describes a new wafer dicing method using fixed diamond scriber and precision servo mechanism and determination of several parameters - scribing depth, scribing force, scriber inclined angle, scribing speed, and factor for scriber replacement - for a new dicing machine using scriber.

Statistical and microscopic investigation of disc segment wear related to sawing Ankara andesites

Despite the advancement in the technology, and the introduction of many synthetic materials, hard rock still keeps its vital importance in daily constructive and decorative consumption. The hard rock processing sector has shown a rapid development since 1930. Turkey has also been affected by this development and many numbers of hard rock processing factories have been established in the last 15 years. The import of basic machines, equipment and consumables in these factories constitutes a major economic problem in this sector. Disc consumption is the most important economic expenditure during the processing of hard rocks. Unsuitable manufacturing of discs and inappropriate adjustment of machine parameters to the rocks to be cut, causes the discs to deteriorate rapidly, leading to eventual economic loss [1]. The circular diamond saw blade contains a steel core which has diamond impregnated segments brazed on the periphery (Fig. 1). The segments (metal bonds) have two basic functions. These are to hold the diamond tight and to erode at a rate compatible with the diamond loss. Due to a large variety of sawing conditions many metal matrix compositions are in general use. Bonds based on copper, various bronze compositions, and on cobalt, tungsten, and tungsten carbide as well as combinations thereof cover a wide range of stone sawing applications. Sometimes small additions of iron, nickel, etc. are made to aid the manufacturing process or in the belief that the addition improves diamond retention or matrix wear properties; however, the complexity of compositions encountered in production practice, which in same cases comprise seven components, makes a scientific approach to the total problem extremely difficult or even impossible [2]. In general, many factors affect the stone cutting by a circular saw blade. These factors can be written in three groups (as shown in Table 1) [3]. The first important factor is the engineering properties of the material. The clue of the suitable values of parameters to reach the effective result is constant parameters. The physico-mechanical, mineralogical and petrographical properties must be analyzed before the sawing test and these results must be used in the producing part of the segment and saw blade. The performance of the sawing with a disc cutter is affected by diamond type, the size of diamond, the concentration of diamond and the properties of the metal bond (matrix). In general, the diamond crystals must have sufficent strength to withstand the repeated cutting forces during the granite sawing process. If the diamond is too weak in strength, it will easily produce macro-cracks and crushed particles. It will also cause the blade to act hard so that possibly glazing will occur. Conservely, if the diamond has very high strength and toughness, it will be difficult to fracture it to produce new cutting points and edges. In addition, it will be polished to give the blade a glazed appearance. The choice of the optimum diamond type for a given application depends on many factors, such as the stone type, the cutting conditions, the type and the quality of the machine, etc. [4]. Luo and Liao [4] report that various studies have been conducted to investigate the effects of the diamond type and size of wear and sawability in the processing of stone with diamond saw-blades. Jennings and Wright [5] stated that hard materials usually require a smaller size diamond than do softer stones because the load per particle is not sufficiently high and greater clearence is required for swarf. Conversely, if large diamond grits are used on hard materials, the penetration of the *Corresponding author. Department of Applied Science, University of Arkansas at Little Rock, Arkansas 72204, USA. Fax: +1-501-5698020. E-mail address: aseyuboglu@ualr.edu (A.S. Eyuboglu).

Machining-induced surface texture effects on the flexural properties of a graphite/epoxy laminate

The effects of surface texture induced by secondary processing on the flexural properties of a graphite/epoxy laminate were evaluated. Test specimens were machined by three methods including the abrasive waterjet, circular diamond saw and shaper planer mounted with polycrystalline diamond tool inserts. Machined surface topography was evaluated by surface profilometry as well as scanning electron microscopy. Flexural strength and modulus were obtained from fourpoint flexure loading to failure and Weibull statistics were used to evaluate characteristic strength and modulus. Although the textures of the machined surface representative of each process were different, no difference in bulk strength of the graphite/epoxy laminate was noted under bending loads.

FRACTURE STRENGTH STUDIES OF POLYCRYSTALLINE DIAMOND FILMS PRODUCED BY DC PLASMA CVD

The fracture strength of Polycrystalline diamond films produced by DC plasma CVD is investigated. The fracture strength of circular diamond film was measuned by a burst pressune technique. Experimental results have shown that the fracture strength is considerably dependent on grain size, sample thickness, apertune radius, methane concentration and substrate temperature. The results have also been discussed.