Papers by Keyword: End Milling

Abstract: Machining processes on hybrid composite materials involve activities such as surface cutting, hole drilling and other cutting processes to achieve final shape and dimension of the composite product. There were several unexpected situations during the process, such as ununiform vibrations due to inconsistent of natural fiber structures and nonideal cutting conditions lead to progressive tool wear and low quality of the cutting surface. In this study, an experimental approach was conducted on the milling process of polyester matrix-based composites reinforced with abaca and glass fibers, produced through the press molding process. The milling process was utilized by a 10 mm diameter 4-flute carbide end mill cutter with a 45-degree helix angle. The study aimed to investigate the influence of cutting conditions (spindle speed, feed, and depth of cut) on vibration during the milling process of abaca-glass fiber composites. Three levels of each cutting parameters were determined based on cutting tool working capabilities, i.e. the spindle speed = 2000, 3000 and 5000 rpm, the feed = 0.004, 0.007 and 0.10 mm/tooth, and depth of cut = 1, 1.5 and 2 mm. The Design of Experiment (DOE) was constructed by Box-Behnken technique of Response Surface Methodology. The down milling process were conducted for all scenario of DOE, and the vibration was measured using a digital accelerometer. The results of the study indicated that vibration increased with the increase of spindle speed, feed, and depth of cut. The results show that the maximum vibration value (0.0206 m/s²) was obtained at a spindle speed of 5000 rpm with a feed of 0.07 mm/tooth and a depth of cut 2 mm. Meanwhile, the minimum vibration value (0.0143 m/s²) was obtained at the spindle speed 2000 rpm, feed 0.04 mm/tooth and depth of cut 1.5 mm.

Abstract: This study investigated the effects of tool runout on chatter vibration taking images of a machined surface to assess the vibration strength, number of vibrations, and phase difference depending on the spindle speed and axial depth of the cut. This study obtained significant results regarding the stability pocket represented by the spindle speed. We observed that the stability limit changed depending on tool runout.

Abstract: The CNC milling process is one of the most valuable traditional machining processes for machining hardened material by using various coated end mill tools. The attention of the current study has been done on end milling of hardened AISI D2 tool steel which is a commonly used tool steel grade in a press machine. The material removal rate is an essential aspect of improving productivity and reducing lead time and production costs. MRR has been considered as a response in this experimental work. A number of experiments were conducted using the design of the experiment via response surface methodology (RSM). MRR was calculated for each machining performance. A mathematical model of MRR was found using response surface methodology.

Abstract: A material with exceptional levels of abrasion resistance, compressive strength, and hardness is known as bearing steel, also known as EN-31 high-grade carbon alloy steel. It has several uses, including the bulk manufacturing of roller bearings, taps, gauges, ejector pins, swaging dies, etc. The lowest surface roughness (Ra) and highest material removal rate (MRR) are sought for this alloy steel in order for it to be used successfully in a range of applications. In the experiment, a L9 Taguchi orthogonal array design was used to CNC end mill EN-31 steel using a bullnose end mill carbide tool with inserts. This study presents a way for enhancing process factors such as cutting speed, depth of cut, feed rate, and tool corner radius that result in desirable output responses. Taguchi and Taguchi-Grey analyses are used to show the best input values that reduce surface roughness and increase MRR. The lowest level of surface roughness could be attained using the operating parameters of 3000 rpm cutting speed, 500 mm/min feed rate, 0.25 mm depth of cut, and 1.00 mm tool corner radius, while the highest level of material removal rate could be attained using 3000 rpm cutting speed, 2500 mm/min feed rate, 0.25 mm depth of cut, and 1.00 mm tool corner radius.

Abstract: The instantaneous uncut chip thickness is an important parameter in the study of milling force model. By analyzing the real tooth trajectory in milling process, accurate instantaneous uncut chip thickness can be obtained to solve the complex transcendental equation. Traditional chip thickness models always simplify the tooth trajectory to get approximate solution. A new instantaneous uncut chip thickness model is proposed in this paper. Based on real tooth trajectory of general end milling cutter, a Taylor's series is used to approximate the involved infinitesimal variable in the transcendental equation, which results in an explicit expression for practical application of the uncut chip thickness with higher accuracy compared to the traditional model.

Abstract: In this study, tool edge temperature was measured by a two-color pyrometer with an optional fiber. During one revolution of spindle, the tool edge passes over the fine hole at workpiece after cutting workpiece. An optical fiber inserted into the fine hole transmits infrared ray radiated from tool edge to two detectors with different spectral sensitivities. One peak signal from each detector can be obtained by each spindle revolution. The tool edge temperature can be calculated by taking the ratio of outputs from these two detectors. The relation between cutting heat calculated from cutting force and tool edge temperature was discussed. The tool edge temperature at the same cutting heat could be compared. The wet cutting condition caused lower tool edge temperature than the others at the same cutting heat. MQL and dry showed almost same tool edge temperature. The dispersion of tool edge temperature in wet cutting is wider than that in dry cutting and MQL cutting.

Abstract: As titanium alloys have a high strength-to-weight ratio and superior corrosion resistance, they are widely used in the aerospace, biomedical, and automotive industries. However, these alloys exhibit very poor machinability, which results in problems such as short tool life. This study investigates the effect of the cutting atmosphere on tool wear during high-speed end milling of the titanium alloy Ti6Al4V. Dry cutting, cold air jet cutting, cutting fluid mist jet cutting, and cutting fluid flush cutting were considered in order to determine the optimum cutting atmosphere and conditions. For down-cutting speeds of 200−300 m/min, the cutting atmosphere and cutting speed were adopted as experimental parameters. Down-cutting was performed in order to measure the width of the tool flank wear land as the cutting length was increased. The results indicated that the optimum cutting method was cold air jet cutting. For a cutting length of 500 mm, this method produced a narrower flank wear land than dry cutting. In addition, for longer cutting lengths of up to 4000 mm, the wear rate for cold air jet cutting was less than or equal to that for dry cutting, and no chipping or excessive wear was observed.

Abstract: Recent developments in the composite materials with high performance increase its range of application most widely but the major disadvantage of these novel materials is machining. The selection of proper process parameters plays an important role in distinguishing machining quality. This work mainly concentrates on the selection of process parameter for minimizing the surface roughness in end milling operation for the newly developed aluminium rock dust metal matrix composite. Taguchi method is used to design and accordingly L27 orthogonal array with five factors viz particle size, weight percentage, cutting speed, feed and depth of cut each at three levels is employed. The experiments were performed in a CNC vertical machining center and corresponding surface roughness values are measured. From the collected data, ANOVA is performed and observations reveal that feed rate influence more on surface roughness followed by particle size, depth of cut, weight percentage and cutting speed.

Abstract: To evaluate and optimize the cutting process from the effective, qualitative and economic point of view, the detailed knowledge about size, direction and orientation of cutting forces is necessary. Cutting forces are an important indicator of machining performance. It helps to understand every single action which occurs during the machining process. In this study, the influence of selected cutting parameters (cutting speed and feed rate) on the behavior of cutting force components were experimentally investigated. AlMgSi1 aluminum alloy (EN AW 6082) was milled in dry and wet machining conditions utilizing uncoated sintered carbide end mills with a different helix angle. Cutting force components were measured and statistically analyzed with using of ANOVA.

Abstract: By considering several applications of aluminum based particle reinforced composites especially in automobile, aerospace and electronic industries, in this work, prediction of machinability responses of A356 alloy-SiC particles (5, 10, 15 and 20 vol%) reinforced metal matrix composites is described. Composites were synthesized by vacuum hot pressing (VHP) assisted powder metallurgy (P/M) process. Effect of cutting speed (Vc), feed (f), depth of cut (d) and quantity of SiC (vol %) on machinability of composites in terms of material removal rate (MRR) and resultant cutting forces (F_R) during end milling were investigated. Milling experiments were carried in dry condition based on central composite design and KISTLER dynamometer was used to measure cutting forces. Resultant cutting force values were increased from 21 to 105 N with an increase in ‘f’ and ‘d’, but decreased with increase in ‘Vc’. Increase in machining parameters increased the MRR from 2.3 to 8.6 × 10³ mm³/min and increase in SiC reduced the MRR. Statistical modeling with cubic response equations were used to predict the results and predicted results were closely matching with experimental values.