Papers by Keyword: Taper Angle

Abstract: Abrasive Waterjet Machining (AWJM) has significant advantages, such as being environmentally friendly, used for machining hard-to-cut materials, and do not cause a heat-affected zone. More machining tests are needed to understand the concept of material machinability in AWJM to increase process flexibility and produce parts with higher productivity, better accuracy, and surface quality. This paper presents drilling and slotting experiments through different metallic materials at fixed machining conditions to evaluate their machinability using AWJM. It introduces new machinability indices that arrange the tested materials concerning their machinability rating. Drilling indices include volumetric removal rate (VRR), penetration rate (PR), specific removal rate (SRR), and taper angle (TA). The paper correlates VRR, PR, drilling power, and Young’s modulus of the tested materials. In the case of slotting, VRR, kerf taper angle (TA), and the average surface roughness, Ra, were measured and used as indices of machinability. Cost analysis was also performed to introduce an economical index of machinability for both AWJ drilling and slotting AWJM operations.

Abstract: Due to outstanding material qualities such as higher strength to weight ratio, resistance to corrosion and resistance to fatigue, titanium alloys (Ti-6Al-4V) are widely applied in aerospace industries. Such a challenging to machine and necessary expensive convenctional machinery materials can cut using Electrical Discharge Machining (EDM). This work involves the study of influence of process characteristics on the performance quality of EDM during machining of Ti-6Al-4V. The process characteristics that are considered in this study are Current (9-15amps) or Input power (I.P. of 3-5 kVA), pulse on (60-80 μsec) and pulse off (20-40μsec) times, the pressure of dielectric fluid (6-10 MPa). The effectiveness of the EDM is measured using rate of tool wear (TWR) and rate of material removal (MRR) during machining, taper angle and surface roughness (SR). Dry brass multi hole tool electrode is used along with deionized water as the dielectric medium. Taguchi L18 orthogonal design is used for experimentation. The optimal combination of process characteristics is determined.

Abstract: Bellows are a cylindrical shell with a corrugated part, widely used in aviation engineering as a movable sealing element to balance pressure and temperature differences, which ensure continuous and accurate system operation. The use of bellows expansion joints provides reliable and effective protection of pipelines from static and dynamic loads arising from deformations and vibration. Welded-edge bellows are a popular choice for regulating and controlling fuel supply in aircraft devices. The ability of the compensator to perceive deformations is determined by its assigned operating time, which describes how many cycles, and with what amplitude, the bellows compensator perceives without damage. A method for stamping bellows from tubular billets by using magnetic-pulse field in rigid dies, including sequential shaping of corrugations by distributing the internal magnetic pressure with axial movement of the free end of a tubular billet, characterized in that the material of the tubular billet for shaping corrugations is selected in accordance with its relative elongation.

Abstract: An engineering technique has been developed that makes it possible to determine the power regimes of the process of crimping a tubular billet in a conical die, taking into account the effect of deformation conditions. The influence of the geometric parameters of the workpiece and tool, the crimping coefficient and non-contact deformation on the axial stress of the crimping process is studied. The main factors influencing the limiting values ​​of the workpiece crimping factor are established. Calculations are performed for the crimping process performed on an open circuit (without stop block), taking into account the friction and hardening of the material. The obtained results are in good agreement with the known experimental data and can be used in the development of the processes of crimping of pipe billets.

Abstract: Silicon nitride (SiNx), an important material used as a dielectric layer and passivation layer in thin film transistor liquid crystal display (TFT LCD) was patterned by a non-lithographic process. SiNx was deposited by plasma enhanced chemical vapor deposition (PECVD) on glass substrate. Laser photoablation can effectively pattern 5 µm diameter with 200 nm depth hole in SiNx thin films with laser photoablation. The threshold remove fluence is 1350 mJ/cm² with 1 laser irradiation shot. The contact-hole taper angle as a function of the laser irradiation shot number. The taper angle increased with increasing the laser irradiation shot number. The contact-hole taper angle etched profile was successfully controlled by vary the laser irradiation shot number.

Abstract: Flexural motion of a cantilever bar can be used to monitor the taper angle measurements of the bar without incorporating any geometric measurement. This provides non-destructive taper measurement with fast processing in manufacturing line. The laser ablation of a free end of the cantilever bar enables to generate a recoil pressure at the irradiated surface while resulting in external forcing function for the initiation of the flexural motion. Consequently, in the present study, laser induced ablation of free end tapered cantilever bar and resulting displacement and frequency of the flexural motion is examined. The study is extended to include influence of positive and negative bar taper angles on the flexural characteristics. In addition, deviation of displacement and frequency of the flexural motion due to tapered bar from the parallel bar is examined. It is found that the flexural characteristics of the tapered bar enable to determine taper angle of the bar with high accuracy.

Abstract: The objective of this experiment is to study the effect of taper angle of the optical fiber microprobe in power collection. Optical fiber microprobes with taper angle from 10° to 23° were fabricated using the automatic fusion splicer by applying one-sided pulling and electric arc heating technique. It was found that the maximum power detected by a small taper angle probe was only -34.22dBm. The highest optical power collected by the optical fiber microprobe in this study was -25.01dBm with taper angle of 22.9°. Large taper angle probe receives more light at the tip which increases the sensitivity of the probe.

Abstract: Titanium nitride-aluminium oxide (TiN-Al2O3) is a new generation ceramic composite material having potential for many industrial applications as it possess high resistance to thermal degradation, anti-wear and anti-abrasion properties. In the present research the characteristic features of EDM process are explored through Taguchi methodology based experimental studies with various process parametric combinations. Finally the process has been optimized using Genetic algorithm based Pareto optimization search. From Pareto optimal search the technology guideline for optimal parameter settings have been selected. The present research approach is extremely useful for maximizing the productivity while maintaining the geometrical accuracy within desired limit.

Abstract: This paper discusses the microfabrication of microholes using focused ion beam and investigation of geometrical integrity of microholes. Different combination of aperture size, probe current, acceleration voltage was applied for micromachining and optimized based on taper angle. Microholes with 3.0 μm of diameter were milled according to the optimized parameter using bitmap mode. The depth range of microholes was 1.0-5.5 μm. The hole’s depth and taper angle were investigated for characterization. Each of the microholes was cross sectioned for investigation. A relationship of taper angle (θ), depth and aspect ratio were plotted. Low aspect ratio (less than 1) would give the lower taper angle and hence better integrity. Acceleration voltage of 25 kV, probe current of 41.5 pA and aperture size of 4 nm produced lower taper angle for different aspect ratio.