A Study of the Vibrational Dynamics of an Endrill Clamped by Side-Locking

1993 ◽  
Vol 115 (4) ◽  
pp. 438-443 ◽  
Author(s):  
M. Rahman ◽  
M. A. Matin ◽  
K. H. W. Seah
Keyword(s):  
Fourier Analysis ◽  
Frequency Response ◽  
Centrifugal Force ◽  
Spindle Speed ◽  
Drill Bit ◽  
Vibrational Dynamics ◽  
Stability Chart ◽  
Harmonic Variation ◽  
Oval Shape

An endrill is clamped by a side-locking device. The shape of a hole obtained by such a drill is found to be of a distorted oval shape. Fourier analysis of the process reveals that the out-of-roundness of the hole is due to the harmonic variation of the centrifugal force developed on the drill-bit. The chattering ranges of the spindle speed are also shown in a stability chart representing the frequency response of the system.

FEMTOSECOND VIBRATIONAL DYNAMICS OF POTASSIUM DIMER

1996 ◽  
Vol 03 (01) ◽  
pp. 475-477 ◽  
Author(s):  
S. RUTZ ◽  
E. SCHREIBER ◽  
L. WÖSTE
Keyword(s):  
Laser Pulse ◽  
Fourier Analysis ◽  
Delay Time ◽  
Time Range ◽  
Selective Detection ◽  
Vibrational Dynamics ◽  
Probe Technique ◽  
Fs Laser ◽  
Photon Ionization ◽  
Potassium Dimer

Combining the femtosecond pump & probe technique with isotope-selective detection, the dynamics of the [Formula: see text] state could be investigated. The three-photon-ionization (3PI) signal was recorded over a delay time range of 220 ps. A strong oscillation around the zero-of-time dephases within 10 ps. Fourier analysis of the spectrum yields a group of frequencies settled between 63 and 68 cm−1 which can be assigned to the energy spacings in the A state being excited by a 90-fs laser pulse. The corresponding vibrational periods could be estimated to lie between 499 and 520 fs.

Effects of drilling parameters on delamination of kenaf-glass fibre reinforced unsaturated polyester composites

2021 ◽  
pp. 152808372110620
Author(s):  
AR Ngah ◽  
Suhad D Salman ◽  
Z Leman ◽  
SM Sapuan ◽  
MFM Alkbir ◽  
...  
Keyword(s):  
Glass Fibre ◽  
Feed Rate ◽  
Unsaturated Polyester ◽  
Spindle Speed ◽  
Taguchi Methods ◽  
Drilling Process ◽  
Drill Bit ◽  
Influence Of Process Parameters ◽  
Drill Bits ◽  
Glass Fibre Reinforced

Drilling is a secondary material removal and usually carried out to facilitate fastening of parts together. Drilling of composite materials is not usually a problem-free process. Issues related to delamination composite laminates need to be addressed because it introduces the stress concentration point on the composite. This study focussed on the influence of process parameters such as spindle speed, feed rate, type of drill bits and geometry on the extend of delamination experienced by the composite during the drilling process of kenaf-glass fibre-reinforced unsaturated polyester composite, and the delamination measurements were taken under a microscope. Taguchi methods and analysis of variance were employed to find the optimal parameters. From the results, the most significant parameter was the feed rate. The minimum delamination was achieved when the feed rate was 0.05 mm/rev and spindle speed was 700r/min using both types of drill bits. The quality of the drill hole using the twist drill bit has been proven to be better than the brad drill bit.

Experimental Study of Aeroacoustics in Supersonic Nozzles

2002 ◽  
Author(s):  
Kei Okamoto ◽  
Kazuyasu Shimura
Keyword(s):  
Experimental Study ◽  
Shock Waves ◽  
Fourier Analysis ◽  
Frequency Response ◽  
Pressure Ratio ◽  
Flow Conditions ◽  
Schlieren Method ◽  
Supersonic Nozzles

In supersonic nozzles, changing pressure ratio varies not only flow conditions but also noises. In order to clarify the relationships between noises and flows (such as shock waves and separation), the present study was conducted using the Fourier Analysis of aerodynamic noises and the Schlieren method. From the investigation, it was found that when the flow was separated from one side of the nozzle, the peak of the spectrum of the frequency response was at around 2000Hz. However, when the flow was in the whole area, the peak of the spectrum was at around 5000Hz.

scholarly journals Investigating the Efficacy of Adhesive Tape for Drilling Carbon Fibre Reinforced Polymers

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1699
Author(s):  
Chander Prakash ◽  
Alokesh Pramanik ◽  
Animesh K. Basak ◽  
Yu Dong ◽  
Sujan Debnath ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Feed Rate ◽  
Research Work ◽  
Spindle Speed ◽  
Adhesive Tape ◽  
Drill Bit ◽  
Scotch Tape ◽  
Error Surface ◽  
Drill Diameter ◽  
Circularity Error

In the present research work, an effort has been made to explore the potential of using the adhesive tapes while drilling CFRPs. The input parameters, such as drill bit diameter, point angle, Scotch tape layers, spindle speed, and feed rate have been studied in response to thrust force, torque, circularity, diameter error, surface roughness, and delamination occurring during drilling. It has been found that the increase in point angle increased the delamination, while increase in Scotch tape layers reduced delamination. The surface roughness decreased with the increase in drill diameter and point angle, while it increased with the speed, feed rate, and tape layer. The best low roughness was obtained at 6 mm diameter, 130° point angle, 0.11 mm/rev feed rate, and 2250 rpm speed at three layers of Scotch tape. The circularity error initially increased with drill bit diameter and point angle, but then decreased sharply with further increase in the drill bit diameter. Further, the circularity error has non-linear behavior with the speed, feed rate, and tape layer. Low circularity error has been obtained at 4 mm diameter, 118° point angle, 0.1 mm/rev feed rate, and 2500 RPM speed at three layers of Scotch tape. The low diameter error has been obtained at 6 mm diameter, 130° point angle, 0.12 mm/rev feed rate, and 2500 rpm speed at three layer Scotch tape. From the optical micro-graphs of drilled holes, it has been found that the point angle is one of the most effective process parameters that significantly affects the delamination mechanism, followed by Scotch tape layers as compared to other parameters such as drill bit diameter, spindle speed, and feed rate.

scholarly journals Study of Complex Helical Drill with a “S” Type Chisel Edge Tip Orient to Carbon Fiber Reinforced Plastics

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yu He ◽  
Xiaolong Zhou ◽  
Ping Zou ◽  
Kun Liu
Keyword(s):  
Carbon Fiber ◽  
Axial Force ◽  
Great Influence ◽  
Spindle Speed ◽  
Drill Bit ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics ◽  
Carbon Fiber Reinforced

In this paper, a complex helicoids’ drill tip of “S” type chisel edge grinded with a three-parallel universal CNC grinding machine tool is carefully studied to obtain the optimum drill bit tip geometry parameters. The effects of experimental parameters, such as apex angle, chisel edge incline angle, and structure circumference rear angle, on the quality of the drilling hole and the machining force were studied from the orthogonal experiment compared with the ordinary drill bit. The range of technological parameters are confirmed which should be used during the drilling process of carbon fiber reinforced plastics (CFRP) in order to realize the reduction of cutting defects such as cutting force and spurs. The effect of spindle speed and feed on the drilling behaviour of the experiment using optimum complex helicoids’ drill tip is also analyzed. It is found that the feed has a great influence on the drilling axial force and the spindle speed has little influence on axial force, but great influence on torque.

The influencing mechanism of drilling parameters on micro drilling temperature on the basis of calibration of surface emissivity of micro drill bit

Circuit World ◽  
2016 ◽  
Vol 42 (2) ◽  
pp. 63-68 ◽  
Author(s):  
Hongyan Shi ◽  
Jiali Ning ◽  
Qiuxin Yan
Keyword(s):  
Influencing Factor ◽  
Spindle Speed ◽  
Drill Bit ◽  
Surface Emissivity ◽  
Simple Method ◽  
Content Type ◽  
Drilling Temperature ◽  
Drilling Parameters ◽  
Micro Drilling ◽  
Micro Drill

Purpose The purpose of this paper is to calibrate the surface emissivity of micro drill bit and to investigate the effect of different drilling parameters on the temperature of micro drill bit in printed circuit board (PCB) micro drilling process. Design/methodology/approach The surface emissivity of micro drill bit was obtained by experiments. Analysis of variance (ANOVA) was applied in this study to analysis the effect of different drilling parameters on the temperature of micro drill bit in PCB micro hole drilling. The most significant influencing factor on micro drill bit temperature was achieved by ANOVA. Findings First, the surface emissivity of cemented carbide rod decreased from 0.4 to 0.32 slowly with temperature in the range of 50-220°C. Second, the most significant influencing factor on the micro drill bit temperature was spindle speed among the drilling parameters including spindle speed, retract rate and infeed rate. Research limitations/implications In this paper, the influence of roughness of black coating, carbide rod and micro drill bit on the surface emissivity calibration and the temperature measurement was not considered. Originality/value A new simple method has been presented to calibrate the surface emissivity of micro drill bit. Through calibrating the surface emissivity of micro drill bit, the temperature of micro drill bit can be measured accurately by infrared thermometry. Analyzing the influences of different drilling parameters on the temperature of micro drill bit, the mechanism of drilling parameters on drilling temperature is achieved. The basis for the selection of drilling parameters to improve the hole quality is enhanced.

Frequency components and positional changes in electrocardiogram of the adult rat

1963 ◽  
Vol 18 (2) ◽  
pp. 261-263 ◽  
Author(s):  
Evangelos T. Angelakos ◽  
Pamela Bernardini
Keyword(s):  
Fourier Analysis ◽  
Frequency Response ◽  
High Frequency ◽  
Sine Wave ◽  
High Frequency Response ◽  
Adult Rat ◽  
Frequency Components ◽  
The Mean

Standard limb electrocardiograms of the adult rat (4–5 months old) were studied using cathode-ray oscillographic techniques. Fourier analysis revealed that the main QRS components can be represented with sine-wave frequencies of 50–400 cycles/sec. Gross distortion was observed with filters providing a high-frequency response of less than 250 cycles/sec. The mean QRS axis was found to be quite sensitive to positional changes. Submitted on August 8, 1962

scholarly journals Comparative Analysis in Drilling Performance of AA7075 in Different Temper Conditions

2021 ◽  
Author(s):  
ESER YARAR ◽  
Alpay Tamer ERTURK ◽  
Funda Gül KOÇ ◽  
Fahri VATANSEVER
Keyword(s):  
Tool Wear ◽  
Surface Quality ◽  
Heat Generation ◽  
Chip Formation ◽  
Feed Rate ◽  
Thrust Force ◽  
Spindle Speed ◽  
Drill Bit ◽  
Microstructural Properties ◽  
Drilling Performance

Abstract AA7075 is one of the most suitable materials for aerospace, aircraft, and defense applications with its high yield strength and low-density. In many other modern machining methods, conventional drilling remains the most extensive material removal process in industrial components. The main objective of this study is examining the machinability and surface quality conditions of the AA7075 material with different temper conditions. For this purpose, various temper treatments are implemented to evaluate the impact of microstructural properties on tool wear and surface quality of the drilled holes. The drilling operations have been done on O, F, T4, T6, and T7 temper conditions. Process parameters were three different spindle speeds (715, 1520, and 3030 rev/min) and three feed rates (0.1, 0.2, and 0.3 mm/rev) with HSS-G high-performance ground standard twist drill bit. The present work deals with the effects of temper conditions on thrust force, drilling temperature, tool wear, surface integrity, and chip morphology. Drilling performance is related to the intrinsic microstructural properties of temper conditions. Response surface methodology was used in the evaluation of experiment results. The optimization results showed that while thrust force and torque are not significantly affected by change in spindle speed, they are sensitive to increase in feed rate. Heat-generation on the drill bit is the lowest at low levels of both the feed rate and spindle speed parameters. Among different temper conditions, the AA7075-T6 condition sample is processed with continuous chip formation and resulted in the best hole surface quality. The 3D finite element modelling of the drilling process was carried out, and the drilling performance of AA7075-T6 was evaluated in terms of thrust force, heat generation, and chip formation.

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