Diamond Grinding Tools Research Articles

Abrasive points for drill grinding of carbon fibre reinforced thermoset

In this study, an approach for using diamond grinding tools to machine holes in epoxy carbon laminates is described. The development of a suitable tool design and the influence of the cutting parameters are presented. With these tools, large total drilling lengths can be achieved without significant grain wear. Analysis of the results shows that the coolant supply can be reduced without exceeding the resin's glass transition temperature. In addition to the experimental results, a process simulation is applied to improve the tool layout and hence to avoid material clogging at the grinding layer.

Effect of Arraying Patterns of Diamond Grits on the Grinding Forces of Mono-Layer Brazed Diamond Tool

Four uniform patterns include grid (GD), concentric circle (CC), spiral (SL) and uniformly random (UR) and one non-uniform (NUR) pattern of diamond grits are designed to fabricate mono-layer brazed diamond grinding tools. The grinding forces of five tools in the cut-in and the stable grinding processes are tested and compared. The results showed that NUR tool has the higher lateral and normal grinding forces than that of other uniformly tools in the cut-in and the stable grinding processes. GD owns the lower and smoother grinding forces than that of other tools in the cut-in process. In the stable grinding process the mean grinding forces of UR tool, namely FLM and FZM, are higher than that of GD, CC and SL tools. And normally CC and SL tools own the lower grinding forces than that of GD tool, especially at the higher feeding speed.

Effect of Arraying Patterns of Diamond Grits on the Wear of the Mono-Layer Brazed Diamond Tool

. In this paper three uniformly arraying patterns (GD, CC and UR) and one non-uniformly arraying pattern (NUR) of diamond grits are used to fabricate the mono-layer brazed diamond grinding tools. The wear characteristics of those grinding tools are compared. It is found that NUR tool wears faster than other uniformly arrayed tools in the wet grinding. The protrusion of diamond grits on NUR tool is much lower than that on GD, CC and UR tool after 20 h of wet grinding. By tracking one diamond grit’ wear processes on CC and NUR tools in the dry grinding respectively, it is found that the diamond grit on NUR tool is worn with the form of macro-fracture firstly, then is polished with large flattened area. However, the wear of diamond grit on CC tool keeps in a form of micro-fracture and a slow wear rate.

Development of High Performance Monolayer Brazed Diamond Grinding Tool for Ceramics

This study has developed a new kind of high performance monolayer brazed diamond tool for ceramic grinding. The grit size of the diamond brazed in the grinding wheel surface is 300m, which has never been reported in diamond tools for ceramic precision machining. The experiment has achieved wonderful surface finish of Zirconia workpiece. This does owe to the designed and precision conditioned topography of the new developed grinding wheel. The topography of the grinding wheel before and after dressing has been measured by means of laser triangulation method. Then the Zirconia workpiece has been ground. The obtained Ra value decreases with no spark grinding times and the minimum Ra of the ground surface is 0.11m. The study proved that the brazed large grit diamond tools would realize high efficiency and precision grinding, namely, high performance of ceramic grinding.

Effects of nano-AlN on phase transformation of low temperature vitrified bond during sintering process

The effects of nano-AlN and sintering temperature on bending strength and wear resistance of low temperature vitrified bond for diamond grinding tools were studied. Furthermore, the phase transformation during sintering process was investigated by means of thermo-gravimetric analysis (TG), differential thermal analysis (DTA) and X-ray diffraction (XRD). The results show that the higher bending strength and wear resistance of low temperature vitrified bond are obtained by adding nano-AlN in bonds and sintering at optimum temperature. Nano-AlN added in bonds promotes the crystallization during sintering process and refines the grain sizes of crystalline phase.

Influence on Diamonds During the Spraying of Diamond-Bronze Abrasive Coatings

Detonation spraying provides the opportunity to produce diamond grinding tools for the machining of stone, cement, and concrete. Especially the atmospheric conditions of the spraying process yield in a high production flexibility. However, during detonation spraying, the oxygenic atmosphere as well as the thermal and kinetic energy have an impact on the processed diamond. Despite its importance for the tools’ performance, the influence of the spraying process on the superabrasive diamond is predominantly unknown. The potential decrease of the diamond durability and strength due to degradation effects during the production of sprayed diamond-CuSn 85/15 composites has not yet been determined. X-ray diffraction and Raman spectroscopy were used to verify thermally initiated surface reactions of the sprayed diamonds after exposure to the spraying process. Additionally, reference measurements on the degradation of diamonds in oxidizing and inert conditions were carried out to compare the spraying results. Differential thermal and thermogravimetric analyses were employed. To validate the mechanical properties of the diamond superabrasives, friability tests and fracture force tests were performed. It was found that under optimized detonation spraying conditions the thermal and mechanical impact remains low enough to ensure a good reliability of the processed diamonds. The diamond crystal structure endured the spraying process without detectable graphitization or oxidation. Deterioration indicators were not observed in SEM micrographs, x-ray diffraction patterns or Raman spectra. Furthermore, a high durability and strength of the sprayed diamonds were confirmed by mechanical testing.

Development of a micro diamond grinding tool by compound process

This study presents a novel micro-diamond tool which is 100 μm in diameter and that allows precise and micro-grinding during miniature die machining. A novel integrated process technology is proposed that combines “micro-EDM” with “precision composite electroforming” for fabricating micro-diamond tools. First, the metal substrate is cut down to 50 μm in diameter using WEDG, then, the micro-diamonds with 0–2 μm grain is “plated” on the surface of the substrate by composite electroforming, thereby becoming a multilayer micro-grinding tool. The thickness of the electroformed layer is controlled to within 25 μm. The nickel and diamond form the bonder and cutter, respectively. To generate good convection for the electroforming solution, a partition designed with an array of drilled holes is recommended and verified. Besides effectively decreasing the impact energy of the circulatory electroforming solution, the dispersion of the diamond grains and displacement of the nickel ions are noticeably improved. Experimental results indicate that good circularity of the diamond tool can be obtained by arranging the nickel spherules array on the anode. To allow the diamond grains to converge toward the cathode, so as to increase the opportunity of reposing on the substrate, a miniature funnel mold is designed. Then the distribution of the diamond grains on the substrate surface is improved. A micro-ZrO 2 ceramic ferrule is grinded to verify the proposed approach. The surface roughness of R a = 0.085 μm is obtained. It is demonstrated that the micro-diamond grinding tool with various outer diameters is successfully developed in this study. The suggested approach, which depends on machining applications, can be applied during the final machining. Applications include dental drilling tools, precision optic dies, molds and tools, and biomedical instruments.

Fabrication of a miniature diamond grinding tool using a hybrid process of micro-EDM and co-deposition

A novel miniature diamond grinding tool usable for the precise micro-grinding of miniature parts is presented. A hybrid process that combines ‘micro-EDM’ with ‘precision co-deposition’ is proposed. The metal substrate is micro-EDMed to a 50 µm diameter and micro diamonds with 0–2 µm grains are ‘electroformed’ on the substrate surface, producing a miniature multilayered grinding tool. Nickel and diamond act as binders and cutters, respectively. A partition plate with an array of drilled holes is designed to ensure good convection in the electroforming solution. The dispersion of diamond grains and displacement of nickel ions are noticeably improved. A miniature funnel mould enables the diamond grains to converge towards the cathode to increase their deposition probability on the substrate, thereby improving their distribution on the substrate surface. A micro ZrO2 ceramic ferrule is finely ground by the developed grinding tool and then yields a surface roughness of Ra = 0.085 µm. The proposed approach is applied during the final machining process.

Grooving Performances of Developed Micro Diamond Grinding Tool by Electroless Composite Plating on Hard and Brittle Materials

Grooving Performances of Developed Micro Diamond Grinding Tool by Electroless Composite Plating on Hard and Brittle Materials

Shear Strength of Brazed Joint between Diamond Grains and Steel Matrix Using a Ni-Cr Filler Alloy

The joining strength and corresponding fracture mechanism of the brazing interface between diamond grains and tool matrix is one of the primary problems in the development and application of brazed diamond grinding tools. In this study shearing tests were performed for the brazed joints, meanwhile the fracture mechanism and the joining characteristics were analyzed deeply. The results indicate that, depending on the metallurgical integration effect through the atom diffusion between the filler alloy and the metal matrix, and on the strong chemical bond by the new-formed Cr-C compounds between the filler alloy and diamond grains, hard and reliable joining is realized at the grain interfaces, which significantly supports the potential advantages of the latest brazed diamond grinding tools.

Fabrication of Ni-W Electroplated Micro Diamond Grinding Tools and Their Application to Grooving in Silicon(M^4 processes and micro-manufacturing for science (continued))

Ni-W electroplated micro diamond grinding tools with cylindrical carbide substrate having a diameter of 100μm were fabricated in ammonium citrate bath. In a fabrication of the Ni-W electroplated micro diamond tools, the effect of stirring the electroplated liquid on the abrasive grain distribution was investigated. Furthermore, the tool life in machining of the single crystalline silicon with the electroplated tools was examined.

Manufacturing the Schmidt corrector lens for the Pierre Auger Observatory

The Pierre Auger Observatory is designed to provide measurements of Extensive Air Showers initiated in the upper atmosphere by cosmic rays with energies greater than 10 18 eV . One of the employed techniques is air fluorescence detectors with UV filters and a corrector lens. We describe in this article the production process of the corrector lens in Brazil, starting from the design of the machines up to the final tests in the prototype telescope. We have used diamond grinding tools to shape a ring of corrector lens with inner radius of 85 cm and outer radius of 110 cm , divided in 24 segments and with aspherical shape. After the production of a first complete set of segments, we measured a segment shape scanning with a laser. The lens was then installed at the telescope and we measured its overall influence on the spot size, taking pictures of the Vega star.

ECD (Electrochemical In-Process Controlled Dressing), a New Method for Grinding of Modern High-Performance Cutting Materials to Highest Quality

The steadily increasing demand for cutting tools with high wear resistance coupled with an adequate toughness has led to the development of new cutting materials that are extremely difficult to machine by conventional grinding techniques: Cermets, Ceramics, PcBN, PCD. A new method of in-process dressing of metal bonded diamond grinding tools by a controlled electrochemical process, called ECD, opens up completely new ways-of grinding these materials. As a result not only the quality of the ground pieces is strongly improved but also an economical application of multi-layered, metal bonded diamond grinding wheels to the machining of modern cutting materials is achieved, which would be impossible otherwise. This new method has been applied successfully on an actual insert grinding machine.

Cobalt excretion in urine: results of a study on workers producing diamond grinding tools and on a control group

A study was carried out on cobalt (Co) excretion in the urine of 12 workers exposed to known cobalt concentrations in the stone cutting diamond wheel production and in six volunteers: four of these were exposed in the same work environment for a whole workshift and the other two were exposed to cobalt in a cabin under experimental conditions. The kinetics of the urinary excretion was multiphase: (i) a first stage of rapid elimination ( T 1 2 = 43.9 h. ); (ii) a second phase of slower elimination ( T 1 2 ″ = 10 days ); (iii) a longer period of retention, of the order of years, in subjects with higher exposure. In the control group (4 subjects), the excretion proved to be much faster in the first stage ( T 1 2 ′ = 20 h). The different behaviour of the two groups could be related to the different body burden, of cobalt and/or to the possibility of different kinetics induced by continuous exposure to the metal. Moreover, 3 weeks after the removal of the workers from exposure the urinary cobalt concentrations were not within the normal limits of CoU for the general population, (even for workers exposed to cobalt levels of the same order as the TLV). The increase of CoU concentrations in the first 3 h after the end of exposure, stresses the problem of when urine samples for biological monitoring of the workers should be collected. The present study confirms the utility of CoU in discriminating between exposed and non-exposed subjects as well as in assessing high and low level exposure.

A New Grinding Method for Ceramics Using a Biaxially Vibrated Nonrotational Ultrasonic Tool

Summary A new method for grinding ceramics and hard materials by using a non-rotational tool has been developed. In the method a fixed abrasive type grinding tool is vibrated by a complex ultrasonic transducer longitudinally and torsionally at the same time. Experiments showed that the complex ultrasonic vibration keeps grinding force low and stable for a long time in grinding hard ceramics even without rotating the tool. When a diamond grinding tool with a square or triangular bottom is used, this method has a great effect on producing cavities with sharp inner corners of almost zero radius on various hard-to-machine materials.