Experimental Analysis of the Effect of Cutting Conditions on the Initial Penetration in Drilling: A Comparative Study Between Conventional and Split Chisel Drills

2009 ◽  
Author(s):  
Sungwoo Park ◽  
Issam Abu-Mahfouz ◽  
Amit Banerjee
Keyword(s):  
Time Domain ◽  
Drilling Process ◽  
Drill Bit ◽  
Penetration Process ◽  
Initial Penetration ◽  
Split Point ◽  
The Time Domain ◽  
Twist Drills ◽  
Skewness And Kurtosis ◽  
Peak Value

To improve the performance and the capability of the drilling process, it is necessary to understand the mechanics of drilling. In particular, drill bit vibrations lead to undesirable effects such as chatter, hole location and roundness errors. In this study, the wandering motion during initial penetration in drilling is experimentally investigated. Four quantities, namely, mean, peak-to-peak value, skewness, and kurtosis are calculated for the time-domain orbital signals. The orbital signals were obtained using proximity probes. The drilling was performed in plates of aluminum, brass, steel, and stainless steel using conventional point and split-chisel symmetrical twist drills. The conventional and split-point drills show different wandering paths during the penetration process. In general, split-point drills produced larger size orbits with more chatter during initial penetration, but showed better centering. On the other hand, conventional drills were found to produce holes that were more offset with smaller size and smoother wandering motion around the actual centers.

Surgical Drilling: Design and Performance of an Improved Drill

1982 ◽  
Vol 104 (3) ◽  
pp. 245-252 ◽  
Author(s):  
S. Saha ◽  
S. Pal ◽  
J. A. Albright
Keyword(s):  
Compact Bone ◽  
Helix Angle ◽  
Rake Angle ◽  
Peak Temperature ◽  
Published Data ◽  
Drill Bit ◽  
Effective Removal ◽  
Split Point ◽  
And Performance ◽  
Twist Drills

The majority of twist drills used in orthopaedics are very similar to chisel pointed metal drilling bits. Modifications usually observed are reduction of the point angle to 90 deg and sometimes grinding of the entire cutting lip at 0 deg rake angle, which appeared to have been made arbitrarily without any advantage. We have attempted to design a surgical drill bit with the objective of minimization of the drilling thrust and temperature and effective removal of bone chips. Our results showed that the presence of the chisel edge was mainly responsible for increasing the thrust force and the temperature developed. The effects of a constant feed rate and thrust on the peak temperature were also examined. The combined effect of the helix and the point angles on the rake angle which in turn determines the cutting efficiency was analyzed for various types of surgical bits. Based on our results and previously published data from the literature an optimized drill bit was designed with a split point, a point angle of 118 deg, a parabolic flute, and a helix angle of 36 deg and its performance was compared with other existing surgical drill bits. For drilling in compact bone, the new design decreased the thrust load by 45 percent and the peak temperature rise by 41 percent. Simlar improvements were also recorded for drilling bone cement. The time of drilling a bone cortex was also significantly reduced and “walking” on the curved bone surface was eliminated and dimensional tolerance on hole sizes was improved. The new design is likely to reduce the time of surgery and also minimize the tissue damage.

scholarly journals Vibrations in CDFW

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 704
Author(s):  
Daniel Soares de Alcantara ◽  
Pedro Paulo Balestrassi ◽  
José Henrique Freitas Gomes ◽  
Carlos Alberto Carvalho Castro
Keyword(s):  
Time Domain ◽  
Low Frequency ◽  
Welding Process ◽  
Statistical Characteristics ◽  
Crest Factor ◽  
Vibration Signals ◽  
Mode Decomposition ◽  
Complex Process ◽  
The Time Domain ◽  
Peak Value

Continuous drive friction welding is a solid-state welding process that has been experimentally proven to be a fast and reliable method. This is a complex process; deformations in the viscosity of a material alter the friction between the surfaces of the pieces. All these dynamics cause changes in the vibration signals; the interpretation of these signals can reveal important information. The vibration signals generated during the friction and forging stages are measured on the stationary part of the structure to determine the influence of the manipulated variables on the time domain statistical characteristics (root mean square, peak value, crest factor, and kurtosis). In the frequency domain, empirical mode decomposition is used to characterize frequencies. It was observed that it is possible to identify the effects of the manipulated variables on the calculated statistical characteristics. The results also indicate that the effect of manipulated variables is stronger on low-frequency signals.

Time-Frequency Analyzing of Acoustic Emission Signals in Drilling of Glass/Epoxy Composites

2012 ◽  
Author(s):  
Hossein Heidary ◽  
Navid Zarif Karimi ◽  
Mehdi Ahmadi Najafabadi ◽  
Giangiacomo Minak ◽  
Andrea Zucchelli
Keyword(s):  
Acoustic Emission ◽  
Time Domain ◽  
Wavelet Packet ◽  
Matrix Cracking ◽  
Drilling Process ◽  
Damage Mechanisms ◽  
Time Frequency ◽  
Pull Out ◽  
The Time Domain ◽  
Stationary Behavior

Drilling is a dynamic process which causes some defects in composite materials such as delamination, fiber pull out and matrix cracking. Because of non-stationary behavior of drilling process, using online method to monitor these damage mechanisms is inevitable. In this paper, acoustic emission signals and wavelet analysis are applied to monitor drilling action from entry to exit. The results show that the selected monitoring indices from the time domain parameters and wavelet packet coefficients are capable of detecting the drilling stages and damage mechanisms during the process effectively.

Study on the Effects of the Geometrical Parameter of Twist Drill on the Drilling Performance of Stainless Steel

2011 ◽  
Vol 189-193 ◽  
pp. 2251-2254
Author(s):  
Xing Jun Gao ◽  
Ping Zou ◽  
Qing Liu ◽  
Hong He Gao
Keyword(s):  
Stainless Steel ◽  
Unit Length ◽  
Edge Length ◽  
Geometrical Parameters ◽  
Drilling Process ◽  
Drill Bit ◽  
Twist Drill ◽  
Drilling Force ◽  
Drilling Performance ◽  
Twist Drills

The key geometrical parameters of twist drills that had a great effect on the drilling performance of stainless steel were studied by Pro/E and DEFORM-3D softwares. The influence of chisel edge and tip angle of twist drill on the drilling force, torque and tool wear in the drilling process was researched, and meantime the effects were introduced by shortened the chisel edge length or adopted S-shape helical drill points as well. The tip angle of drill bit that affected the main cutting edge length, the cutting load on unit length, the proportion between cutting width and cutting thickness in the cutting lay, the cutting force, the torque, the chip formation and chip removal was introduced in detail. The choice of tip angle of twist drill was introduced. In drilling, it has important instructional significance for improvement of life of drill bit, advancement of productivity of drilling and processing quality of hole.

Apodisation in the time domain

1992 ◽  
Vol 2 (4) ◽  
pp. 615-620
Author(s):  
G. W. Series
Keyword(s):  
Time Domain ◽  
The Time Domain

JOINT INTERPRETATION OF AIRBORNE ELECTROMAGNETIC DATA IN THE TIME DOMAIN AND FREQUENCY DOMAIN

2018 ◽  
Vol 12 (7-8) ◽  
pp. 76-83
Author(s):  
E. V. KARSHAKOV ◽  
J. MOILANEN
Keyword(s):  
Fourier Transform ◽  
Frequency Domain ◽  
Time Domain ◽  
Frequency Interval ◽  
Single Spectrum ◽  
Simultaneous Inversion ◽  
Homogeneous Half Space ◽  
Time Domain Data ◽  
The Time Domain

Тhe advantage of combine processing of frequency domain and time domain data provided by the EQUATOR system is discussed. The heliborne complex has a towed transmitter, and, raised above it on the same cable a towed receiver. The excitation signal contains both pulsed and harmonic components. In fact, there are two independent transmitters operate in the system: one of them is a normal pulsed domain transmitter, with a half-sinusoidal pulse and a small "cut" on the falling edge, and the other one is a classical frequency domain transmitter at several specially selected frequencies. The received signal is first processed to a direct Fourier transform with high Q-factor detection at all significant frequencies. After that, in the spectral region, operations of converting the spectra of two sounding signals to a single spectrum of an ideal transmitter are performed. Than we do an inverse Fourier transform and return to the time domain. The detection of spectral components is done at a frequency band of several Hz, the receiver has the ability to perfectly suppress all sorts of extra-band noise. The detection bandwidth is several dozen times less the frequency interval between the harmonics, it turns out thatto achieve the same measurement quality of ground response without using out-of-band suppression you need several dozen times higher moment of airborne transmitting system. The data obtained from the model of a homogeneous half-space, a two-layered model, and a model of a horizontally layered medium is considered. A time-domain data makes it easier to detect a conductor in a relative insulator at greater depths. The data in the frequency domain gives more detailed information about subsurface. These conclusions are illustrated by the example of processing the survey data of the Republic of Rwanda in 2017. The simultaneous inversion of data in frequency domain and time domain can significantly improve the quality of interpretation.

scholarly journals Broadband spectroscopy of astrophysical ice analogues

2019 ◽  
Vol 629 ◽  
pp. A112 ◽  
Author(s):  
B. M. Giuliano ◽  
A. A. Gavdush ◽  
B. Müller ◽  
K. I. Zaytsev ◽  
T. Grassi ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Time Domain ◽  
Complex Refractive Index ◽  
Far Infrared ◽  
Infrared Region ◽  
Thz Radiation ◽  
The Real ◽  
Thz Range ◽  
The Time Domain

Context. Reliable, directly measured optical properties of astrophysical ice analogues in the infrared and terahertz (THz) range are missing from the literature. These parameters are of great importance to model the dust continuum radiative transfer in dense and cold regions, where thick ice mantles are present, and are necessary for the interpretation of future observations planned in the far-infrared region. Aims. Coherent THz radiation allows for direct measurement of the complex dielectric function (refractive index) of astrophysically relevant ice species in the THz range. Methods. We recorded the time-domain waveforms and the frequency-domain spectra of reference samples of CO ice, deposited at a temperature of 28.5 K and annealed to 33 K at different thicknesses. We developed a new algorithm to reconstruct the real and imaginary parts of the refractive index from the time-domain THz data. Results. The complex refractive index in the wavelength range 1 mm–150 μm (0.3–2.0 THz) was determined for the studied ice samples, and this index was compared with available data found in the literature. Conclusions. The developed algorithm of reconstructing the real and imaginary parts of the refractive index from the time-domain THz data enables us, for the first time, to determine the optical properties of astrophysical ice analogues without using the Kramers–Kronig relations. The obtained data provide a benchmark to interpret the observational data from current ground-based facilities as well as future space telescope missions, and we used these data to estimate the opacities of the dust grains in presence of CO ice mantles.

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