Papers by Keyword: Deep Hole

Abstract: In drilling the ultra-slim small diameter deep hole of titanium alloy, the problem of chip breaking and chip removal is common. When the drill is working normally, the ultrasonic vibration can be applied for the drill bit to cut the bit in the vibration to form a pulse. The cutting force waveform in drilling, should select the reasonable vibration frequency, amplitude, feed amount, workpiece rotation and other parameters to match, control the size and shape of the chip, get satisfactory chips, and avoid chip clogging. In this study, the ANSYS finite element simulation software was used to simulate the TC4 drilling process, and the difference between ultrasonic vibration drilling and ordinary drilling was analyzed. Drilling experiments were carried out. The experimental results show that compared with conventional drilling, ultrasonic vibration drilling has better surface quality, reduced tool wear and increased material removal rate.

Abstract: In this study, a series of deep micro holes were machined on thick GH4169 super alloy by the trepan drilling, using a millisecond pulsed laser which equipped to the numerical control processing system. The microstructure of the holes including surface and longitudinal morphologies, diameter, taper, circularity, micro cracks and recast layer were systematically characterized. The surface morphology and the longitudinal section of the drilled holes were observed by Scanning Electron Microscope and 3D Laser Scanning Confocal Microscope. The method of Minimum circumcircle method was employed to evaluate the entrance and exit end circularity. The results showed that the melt and spattering accumulating around the holes decreased with the augment of laser power. The diameter of the entrance showed an increasing tendency with the growing of laser power, but the exit end was not seriously affected by the power. The micro cracks and recast layer could be found obviously, the micro cracks appeared in those zones which thermal stress concentrated, the thickness of recast layer is about 20μm and the taper and circularity were optimized at a laser power of 80-100W.

Abstract: Based on the working principle of the capacitive sensor, according to the requirements of deep hole diameter measuring, a capacitance probe sensor was designed, and then the design and type-selection of probe structure, cable inner structure to the capacitance probe sensor were done. At the same time, in order to overcome the measurement error caused by eccentricity, the capacitance sensor probe and inner hole of the corresponding fastener both are designed to a taper, taper positioning is relatively accurate positioning way. The design is to avoid the measurement position offset, and ensures the coaxality on the mechanical structure. The equipotential ring technology effectively overcomes the problem of edge effect of capacitance sensor, and makes the probe’s effective measurement electrode under the condition of limited long, can effectively guarantee the measure precision. By moving the capacitance probe in the hole to the different position, we will realize the deep hole diameter measurement in different cross section.

Abstract: This research aimed to study the machining efficiency of AISI P20 steel by Electrical Discharge Machining (EDM) using rod copper electrode to machining material by 50 mm depth of machining was mainly assessed from Materials Removal Rate (MRR) and Electrode Wear Ratio (EWR). From the experiment designed to use Taguchi technique of data analysis and suitable parameter prediction, the highest MRR was at on-time of 150 μs, off-time of 2 μs and electric current level was at 15 A or 0.25 A/mm². Predicted value was at 19.2395 mm³/min which was equal to real experiment, showing Materials Removal Rate of 19.647 mm³/min (with error of 2.12 percent) .Moreover, it was found that gap would increase with the size of electrode and depth of machining caused by movement of particles removed from side surface of electrode, which cause micro sparks at the side of the material workpiece.

Abstract: Top-quality surfaces are obtained by means of pulse electrochemical finishing (PECF) in neutral electrolyte. The rules of effect of main experimental parameters such as pulse current density, electrolyte flow rate and interelectrode gap on surface quality are analyzed based on the experiments in detail. Moreover, the technique are applied to some typical cases such as surface finishing of fine and deep holes that is more difficult to be machined by the traditional finishing technologies. The results show mirror-like surfaces could be gained by PECF and the surface roughness values could be reduced from more than Ra 1.6μm to less than Ra 0.08μm within several seconds. The experiments show that PECF will play an important role in finishing key parts that is more difficult to be machined by the traditional finishing technologies in the modern manufacturing industries.

Abstract: The BTA tool is a tool for deep-hole drilling. The deep-hole which be machined by this tool has the excellent straightness and roughness. However, it's use a lot of cutting oil. Therefore, it will lead to environmental destruction. Thereupon, in this study, it is applied the near-dry system to the deep-hole drilling with BTA tool. In the previously, it was designed the experimental device with a double tube system, and the cutting experiments was carried out. In this system, the chip is discharged through inside of the inner tube. Frequently, the chip is cannot be divided by the adhesion on the cutting edge during drilling. Thereby, the chip was jammed into the inside of tool’s tube. It is tried experiments of various cutting conditions, cutting speed and feed rate, by tools with different geometry, height and width, of the chip-breaker. And, it is observed the discharge condition of chips, the chip’s shape and the situation of adhesion. As a result, it can be found the optimum cutting condition and tool’s geometry for a continuous chip’s discharge while the deep-hole is drilling by a BTA tool in near-dry system.

Abstract: In the drilling process for deep hole, the continuous chips often jam up due to the difficulty of chip removal, and the chips cause problems such as tool breakage and deterioration of the surface quality. The measures of chip removal must be adopted, especially for small diameter deep hole, the chip removal space is limited and thickness and length of chips can directly influence the chip removal, the chip size are required as a precondition for chip removal. In this study, the feed is periodically varied in numerical control machine, and the length of chip can be controlled, then the chip breaking is realized with no addition special chip breaking mechanism, which combines with negative pressure suction mechanism for chips, and solves the problem of chip breaking and removal.

Abstract: In order to drill a deep steps hole with a big belly in hard-cutting material parts, a special boring cutter is designed by analyzing cutting technology of this kind of parts. On the basis of single-tube inner chipremoval ejector drill (SIED), a new tool radical movement mechanism is pulled by a wedge plate installed inside the tool rod at one end of the rod and plate is driven horizontally by a motor controlled by a numerical control device. A straight hole whose diameter is same as the minimum one of the steps holes is firstly machined by an entity drill. And then the tool is used to get the big belly hole in the middle of the straight hole and begin to move radically at the same time as axial feed just in the location of belly. The tool is retreated to the original position at the end of the big belly. Experiments show that this kind of tool can not only drill belly holes effectively but also improve the processing quality.

Abstract: Single-edge rigid reaming process has high-speed cutting rigid hinge processing, auto-oriented, low surface roughness of a series of advantages. In this paper, by using of the elastic and plastic theory, we studied the effect of the force acting on the guide block extrusion on the hole wall, proposed the two different cutting states of single-edge rigid reaming processing, and analyzed the conditions of the reaming processing in the extrusion state. By the analysis of experiments, we obtained that in order to achieve the good hole processing surface quality we must make the reaming processing in the extrusion processing state, and we determined the impact of the cutting parameters on the cutting force and surface roughness.

Abstract: This paper presents deep-hole etching process by inductively coupled plasma (ICP),the hole is higher than 400um ,and its diameter is 200um wide. Etching process successfully used in anchor fabrication below 150 um deep in micro-inertial devices, is first used in deep-hole etching .The result is badly, the sidewall surface is coarse, and the sidewall perpendicularity is poor,the dimension difference between upper and down diameter is as large as 35um.Because with the depth increasing , deep-hole etching brings new problem, such as fluorine(F) radical and ions distributing very differently between in down and upper area, also extracting reactant and temperature distribution . To solve above problems, process parameters such as gas flow mass and time in one reaction cycle, source and substrate power, reaction pressure and temperature should be adjusted. Through several experiments, optimal process is applied and the result is satisfied .From SEM figure, The the sidewall surface is smoother, the sidewall perpendicularity is good, the dimension difference between upper and down diameter is controlled in 1.6um,the sidewall angle is 89.78°. The process has been used in deep-hole fabrication of micromachined filter, and the rate of device enhances largely at present.