Papers by Keyword: Drilling

Abstract: This experiment is to investigate delamination damage of carbon/basalt/epoxy hybrid composites on the drilling manufacturing process. The damage is caused by drilling on wet and dry conditions with a twist drill size of 8 [mm], and 10 [mm] have been conducted. This experiment was carried out based on the ASTMD 5470-12 standard. Three hybrid composites have been manufactured for samples such as H₁, H₂, and H₃. Additionally, the carbon fibers reinforced epoxy composites (CFRP) and basalt fibers reinforced epoxy composites (BFRP) as experiment control had built. The aim is to assess the defect zone of carbon/basalt hybrid composite against the drilling. The examination results showed that the feed rate speed of various laminate configurations e.g., H₁, H₂, and H₃, on drilling dried between twist drill of 10 [mm] and 8 [mm] diameters are 50.5 %, 25 %, and 33.2 %, respectively. Also, adding lubricant during the drilling work has reduced peel-out and push-out effectively. The delamination defect has been the high resulted in drilling using drill 10 [mm] in wet or dry conditions. In contrast, delamination defect has occurred minimum on drilling hole using twist drill 8mm in work wet and dry condition. It has still occurred. From this research, the combination sequence of basalt and carbon fiber has the possibility to experience the delaminate damage in dry drilling processes.

Abstract: Recently, researchers and engineers have been interested in the development of hybrid metal matrix composites (HMMCs) for the applications of automotive and aerospace industries owing to their superior properties due to the usage a wide range of material combinations in its manufacturing. The present study focuses on the machining of magnesium based hybrid composites reinforced with CNT (1vol.%) and SiC (2vol.%).The influence of machining parameters such as spindle speed, feed rate, drill diameter and point angle on burr formation and surface roughness on drilling the composites were investigated using Taguchi method. The drilling parameters were optimized by using ANOVA experimental design and also find out the percentage of contribution of each factor. Based on the results, the most influential factor for the burr thickness was spindle speed and point angle. While spindle speed and feed rate were the influencing factors for surface roughness. The analysis revealed that burr height, burr thickness, and surface roughness decreases significantly with an increase in spindle speed.

Abstract: Utilization of natural fibers in a form of filler materials in composite structures has been successfully implemented in a broad range of industrial applications. In general, natural fibers have many advantages over synthetic counterparts, (e.g. glass and carbon) including lower density, ability to muffling vibration as well as its positive environmental impact. Hence, natural fibers can be used to enhance the characteristics of composite polymers. Expected improvements may include good thermal and acoustic insulating properties and better electrical resistance. However, in order to qualify any new developed material for commercialization, machining such as drilling, milling, cutting, bending, etc., becomes essential. In this experimental work, a newly developed Chopped Date Palm Fronds Polypropylene (CDPF/PP) bio-composite, which was mechanically characterized in a previous study, is investigated against conventional drilling operation. The data obtained through machining are processed and statistically analyzed based on Design of Experiment (DoE) to achieve the optimal input parameters using ANOVA and regression model. Moreover, the statistical evaluation of the results is useful to develop mathematical models that can be used with confidence to predict the drilling delamination for future works. In specific, optical microscopy was utilized to measure the dimension of the machined bio-composite surface to calculate the delamination factor.

Abstract: The article discusses the experience of drilling and blasting operations in the conditions of high water cut of the rock massif, it also presents practical experience in modeling and forecasting water inflows into workings. By the example of the Koashvinskoe deposit, the problems of work in conditions of high water cut of the rock mass leading to the collapse and silting of drilled boreholes are considered. The article presents calculations showing the effectiveness of the drainage systems for lowering the groundwater level of a prepared rock mass section. The paper provides a rationale for the optimal mass of bottom charges for the preparation of drains in the rock mass, depending on the water saturation of the mass and the grid of drilled boreholes.

Abstract: The present work deals with the finite element simulation of drilling of fibre-reinforced composites. The simulation is done using commercially available software. Hashin failure criteria has been used to simulate the drilling process. Three dimensional drill model was created and Hashin failure is defined via VUMAT sub-routine. Three-dimensional Hashin failure have larger stress and strain analysis resolution. This research is focused on validating reaction force and accuracy of drill. Reaction force obtained in composite drilling simulation is compared with experimental data. The work is focused on reproducing the simulation of composite modelling and composite damage rather than theoretical explanation of composite material and mathematical model behind the simulation. Thus, laying the knowledge to simulate composite fibres failure.

Abstract: Most machining processes produce burr as a result of plastic deformation. Exit burr strongly affect product quality during assembly and it is difficult to remove them easily. This work aims at minimizing burr produced in drilling of Al6061/SiCp composite fabricated through stir-casting process using HSCO drill. Analysis of experimental results using ANOVA indicated the influence of cutting conditions and drill geometry in reducing the thrust force as well as burr size. Keywords: Drilling, Al6061/SiCp, HSCO drill, ANOVA, Thrust force, Burr

Abstract: The paper presents the results of tribotechnical studies of anti-wear properties of iron-based coatings for light-alloy drill pipes made of aluminum alloys. The description of the tribotechnical stand simulating real processes of drilling in a wide range of conditions is given. Also, the analysis of corrosion resistance of coatings by electrochemical analysis was carried out. The results showed that there is a potential for the use of this type of coating.

Abstract: The description of the basic material for the printboards production is given, its basic physical properties are formulated, the features of machining are shown and the range of problems that arise in this case is determined. We specified common mistakes that could lead to mass marriage in the manufacture of printboard assemblies. The structure and composition of base materials for the production of clad dielectric materials are described in this paper. An equation for calculating the maximum shear stress for a composite material is given. It is shown that nesting and, as a consequence, an increased content of glass fibers through a chain of interrelated factors affects the quality and reliability of the printboard operation and the entire product as a whole. In addition, the dense laying of fibers increases the cutting tool wear significantly. The article provides the technique of the base material choice depending on the distribution structure of glassfiber filaments on which the labor productivity, the quality, the cutter power and the manufacturing cost of the printboards depends.

Abstract: Aluminum based metal matrix composites (AMMC) have found its applications in the automobile, aerospace, medical, and metal industries due to their superior mechanical properties. Fabricated Aluminum based metal matrix composites require machining to improve the surface finish and dimensional tolerance. Machining should be accomplished by good surface finish by consuming lowest energy and less tool wear. This paper reviews the machining of Aluminum based metal matrix composites to investigate the effect of process parameters such as tool geometry, tool wear, surface roughness, chip formation and also process parameters.

Abstract: Electrochemical machining process is an advanced material removal technique offering high precision and introducing no heat damage to the work material. The shape and size of machined area are highly dependent on some process parameters such as voltage, electrolyte and inter-electrode gap. To further enable a more insight into the process performance, this paper investigates the influences of applied voltage, electrolyte concentration and inter-electrode gap on the shape and sizes of hole produced by the electrochemical drilling process. Titanium alloy (Ti-6Al-4V) was used as a work sample in this study as it has been extensively used in many advanced applications. The experimental result indicated that the use of high voltage and high electrolyte concentration can enlarge and deepen hole in the workpiece, while the inter-electrode gap provided less effect to the hole features. The maximum hole depth can reach 300 μm within 60 seconds when the applied voltage of 30 V, the inter-electrode gap of 10 μm and the electrolyte concentration of 10%wt were used. However, with this setup, the obtained cut profile became a non-uniform V-shaped hole. The use of lower voltage was instead recommended to yield a better cut quality with U-shaped profile.