Papers by Keyword: Milling

Abstract: Dolomite has great potential to be employed as filler or nanofiller in polymer composite/nanocomposite system. However, the research on dolomite as filler or nanofiller in polymer composite is still immature, requiring further investigations on how to optimize the dispersion of the dolomite in the polymer matrix, thus improving its properties. Particle size reduction of dolomite can be an efficient approach to increase its surface area and facilitate its dispersion and distribution within polymer matrix in order to develop homogeneous composite/nanocomposite system. In this study, the dolomite in pulverized form was obtained from Perlis Dolomite Industry, Malaysia with the average particle size of 150μm. In order to reduce the size of this dolomite, we have initially employed the planetary ball milling method. Results indicate that the particle size of dolomite has been reduced from 150μm to 2μm after subjected to ball milling process. This shows that upon ball milling procedure, the size of dolomite particle is still in micronmeter. Next, the ball milled dolomite was subjected to tip-sonication process to obtain dolomite in nanosize range. Several tip-sonication parameters, which were; amplitude and number of sonication repetition were applied in order to select the best parameters that can produce the finest dolomite powder. SEM and TEM were used to characterize the microstructure of the raw dolomite and the size reduced dolomite. Our results show that when the ball milled dolomite was tip-sonicated, much smaller particle size was obtained. Dolomite with the smallest particle size (~200nm) was obtained when the tip-ultrasonication was performed 3 times at amplitude of 50. These findings indicate that the combination of ball milling and tip-sonication is an efficient method to produce very fine dolomite particles, up to nanosize range. Furthermore, it is a clean, simple method and not involved any toxic and harmful chemicals.

Abstract: The present work presents the development of a numerical model to assess the machining performance in milling of a 15-5PH stainless steel. At first an experimental campaign was conducted using PVD coated TPUN inserts under three levels of cutting speed and feed: 100-170-240 m/min & 0.25-0.35-0.45 mm/rev. Forces were recorded using a Kistler 9257A dynamometer. For each experimental test, chips were mounted and polished to evaluate the chip thicknesses and contact lengths measured on inserts’ rake face. Regarding the numerical simulation, a 2D Arbitrary-Lagrangian-Eulerian (ALE) was then developed in the study. A tool motion was implemented to mimic the chip thickness evolution occurring during the milling process. These simulations allowed to numerically predict the chip thicknesses, contact lengths and cutting forces which were further compared to the experimental data.

Abstract: Functional surfaces have been widely used for control of physical and/or chemical properties of substances on the surface. In the manufacturing industries, some of micro fabrication approaches such as laser processing have been applied to form textured surfaces, which control the surface functions with topographies. This study presents the surface texturing in cutting with micro-scale structured end mills. Micro-scale nicks are fabricated on the cutting edges of PCD (Poly-Crystalline Diamond) end mills in laser finishing. The cutting operation is conducted to form the chips on each nick with the cutter axis inclination in the feed direction. An analytical model is applied to control the surface structure for the spindle speed, the feed rate, the nick geometry and the inclination angle of the cutter axis. Then, the surface structures were fabricated in the actual cutting process. The machining operation in this study is available in fabrication of the micro-scale structures at high production rates and the structures shape can be controlled in the surface simulation.

Abstract: The article shows the relevance and scientific significance in the use of a combined processing method that combines the cutting process and surface plastic deformation, which provides an increase in the efficiency of processing of the basic flat end surfaces of electrical parts made of copper, the study of the patterns of microrelief formation during mechanical processing and plastic deformation of a copper surface. It was found that the use of a combined tool allows you to combine several transitions, which provides an increase in processing productivity by reducing the machine and auxiliary processing time. Replacing the grinding operation of the existing technological process with diamond burnishing can significantly improve the quality of the processed surface.

Abstract: Hadfield steel is widely used in the manufacture of machines and mechanisms operating in harsh conditions. When machining Hadfield steel parts, problems are due to the strain hardening. The article studies the influence of cutting modes on steel hardness, tool thrust and surface roughness when milling Hadfield steel using cutters with replaceable inserts. The experiments were conducted on a milling machining center using high-productivity cutting tools. The optical roughness measuring method was applied. Hardness was measured with a portable hardness tester before and after milling. The article describes experimental results that show the dependence of the output machining parameters on the cutting speed and feed per tooth. The influence of cutting data on tool life in a finish milling operation was identified. The results will help to improve the quality and productivity and increase the tool life in roughing and finishing Hadfield steel parts.

Abstract: The choice of cutting mode elements in end milling has a significant effect on machining performance. However, an increase in these parameters leads to an increase in cutting force and vibration amplitude. Therefore, the designation of the elements of the cutting mode must be carried out taking into account the dynamic phenomena accompanying milling. The article shows the influence of the depth of cut on the amplitudes of forced vibrations. The choice of the optimal values of the cutting mode during end milling is proposed to ensure the minimum vibration amplitude.

Abstract: The paper is focused on one of the most important component of Portland clinker-on the tricalcium silicate. The study reported in this article is focuses on the changes in crystallite size of synthetic tricalcium silicate obtained using solid state reaction method. Crystallite size changes are monitored during the grinding in three types of laboratory mills in two different conditions. Changing in crystallite size at various grinding time up to 120 minutes are studied with the aid of X-ray diffraction and using the Scherrer equation. It has been found that the most efficient laboratory mill in terms of speed and fineness of the material was the planetary mill.

Abstract: Despite the advanced development in the field of creating new hard-alloy and ceramic tool materials, the use of modern high-speed steels has not yet lost its relevance, and it is especially true for the production of small batches of costly specialized tools, especially since modern strengthening technologies can make it competitive. For example, additive production systems associated with laser or electron beam manufacturing methods create products, including Ti-6Al-4V alloy, with low surface quality, and it is still necessary to apply the additional cutting treatment. The features of milling titanium alloy obtained by the electron beam melting method were revealed. It is determined that the force parameters differ from those in the processing of metal obtained by traditional technologies. Thus, the component of cutting tangential force F_T increases by approximately 15%. At the same time, a 20% drop in the radial force F_R observed

Abstract: The article discusses the issues of chatter damping during milling. The relationship between the amplitude of forced vibrations and the cutting speed has been established. The choice of the optimal values ​​of the cutting condition during end milling is proposed to ensure the minimum vibration amplitude.

Abstract: The present study was conducted to establish adsorbent potential of magnetite nanoparticle ferrous ferric oxide (Fe₃O₄) for removal of Cu(ll) ions in wastewater. In the study, Fe₃O₄ was prepared by synthesizing low-cost recycled mill scale waste in an aqueous solution. Samples of scale wastes were milled and ground using high-energy ball milling (HEBM) at three milling times of 5, 7 and 9 hours. Extraction of Fe₃O₄ was accomplished by magnetic separation technique (MST) and Curie temperature separation technique (CTST). The morphologies and structural properties of Fe₃O₄ were characterized by using X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Fourier-transform infrared spectroscopy (FTIR). HRTEM yielded images in the range of 10-22 nm. Maximum adsorption capacity, q_e, and percentage removal of Cu(II) ions were achieved at 4.45 mg/g and 62.61% respectively after 7 hours of milling time. The present study recorded the smallest particle size of Fe₃O₄ imparting high qe, and percentage removal of Cu (II) ion in an aqueous solution, suggesting its high adsorbent potential.