scholarly journals Lateral Vibrations in Deep Hole Drilling Due to Land Width Variation

2020 ◽  
Vol 4 (2) ◽  
pp. 28
Author(s):  
Marcel Volz ◽  
Eberhard Abele ◽  
Matthias Weigold
Keyword(s):  
Cutting Speed ◽  
Low Frequency ◽  
Negative Influence ◽  
Diameter Ratio ◽  
Hole Diameter ◽  
Hole Drilling ◽  
Radial Vibrations ◽  
Lateral Vibrations ◽  
Drilling Tools ◽  
Land Width

In drilling processes, self-excited vibrations have a negative influence on the achievable drilling qualities and tool life. Low-frequency radial vibrations are characterised by oscillating movements of the tool tip and the generation of lobed holes in drilling. This study focuses on the participation and influence of the land widths of twisted drilling tools on these vibrations. Therefore, drilling tools with different land widths and a length-to-diameter ratio of 12 are used, and different parameters, such as feed rate, cutting speed, coolant pressure, pre-hole diameter, and chuck selection, are varied in a drill-out process. The results show that the land widths have a statistically significant influence on the formation of lateral vibrations and the generation of lobed holes.

scholarly journals Analyzing the Effects of the Kinematic System on the Quality of Holes Drilled in 42CrMo4 + QT Steel

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4046
Author(s):  
Mateusz Bronis ◽  
Edward Miko ◽  
Lukasz Nowakowski
Keyword(s):  
Cutting Speed ◽  
Hole Drilling ◽  
Internal Cooling ◽  
Hole Quality ◽  
The Third ◽  
Kinematic System ◽  
Turning Center ◽  
Dimensional Errors ◽  
The Relationship

This article discusses the relationship between the kinematic system used in drilling and the quality of through-holes. The drilling was done on a CTX Alpha 500 universal turning center using a TiAlN-coated 6.0 mm drill bit with internal cooling, mounted in a driven tool holder. The holes were cut in cylindrical 42CrMo4 + QT steel samples measuring 30 mm in diameter and 30 mm in length. Three types of hole-drilling kinematic systems were considered. The first consisted of a fixed workpiece and a tool performing rotary (primary) and linear motions. In the second system, the workpiece rotated (primary motion) while the tool moved linearly. In the third system, the workpiece and the tool rotated in opposite directions; the tool also moved linearly. The analysis was carried out for four output parameters characterizing the hole quality (i.e., cylindricity, straightness, roundness, and diameter errors). The experiment was designed using the Taguchi approach (orthogonal array). ANOVA multi-factor statistical analysis was used to determine the influence of the input parameters (cutting speed, feed per revolution and type of kinematic system) on the geometrical and dimensional errors of the hole. From the analysis, it is evident that the kinematic system had a significant effect on the hole roundness error.

scholarly journals Analysis of machining-induced residual stresses of milled aluminum workpieces, their repeatability, and their resulting distortion

2021 ◽  
Author(s):  
Daniel Weber ◽  
Benjamin Kirsch ◽  
Christopher R. Chighizola ◽  
Christopher R. D’Elia ◽  
Barbara S. Linke ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Cutting Speed ◽  
Past Research ◽  
Hole Drilling ◽  
Statistical Confidence ◽  
Measured Stress ◽  
Main Driver ◽  
Milled Surface ◽  
Force Signal ◽  
Repeatability Standard Deviation

AbstractMachining-induced residual stresses (MIRS) are a main driver for distortion of thin-walled monolithic aluminum workpieces. Before one can develop compensation techniques to minimize distortion, the effect of machining on the MIRS has to be fully understood. This means that not only an investigation of the effect of different process parameters on the MIRS is important. In addition, the repeatability of the MIRS resulting from the same machining condition has to be considered. In past research, statistical confidence of MIRS of machined samples was not focused on. In this paper, the repeatability of the MIRS for different machining modes, consisting of a variation in feed per tooth and cutting speed, is investigated. Multiple hole-drilling measurements within one sample and on different samples, machined with the same parameter set, were part of the investigations. Besides, the effect of two different clamping strategies on the MIRS was investigated. The results show that an overall repeatability for MIRS is given for stable machining (between 16 and 34% repeatability standard deviation of maximum normal MIRS), whereas instable machining, detected by vibrations in the force signal, has worse repeatability (54%) independent of the used clamping strategy. Further experiments, where a 1-mm-thick wafer was removed at the milled surface, show the connection between MIRS and their distortion. A numerical stress analysis reveals that the measured stress data is consistent with machining-induced distortion across and within different machining modes. It was found that more and/or deeper MIRS cause more distortion.

Hole Accuracy during Deep Hole Drilling for Hydraulic Cylinder Application

2014 ◽  
Vol 984-985 ◽  
pp. 67-72 ◽  
Author(s):  
R. Clifford Benjamin Raj ◽  
B. Anand Ronald ◽  
A. Velayudham ◽  
Prasmit Kumar Nayak
Keyword(s):  
Feed Rate ◽  
Drill Hole ◽  
Hydraulic Cylinder ◽  
High Accuracy ◽  
Diameter Ratio ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Very High ◽  
Continuous Chip

Deep-hole drilling is a process in which the hole length will be very high when compared to diameter of the drill hole (i.e. length to diameter ratio will be greater than 5). Drilling a deep hole with very high accuracy is difficult process. The current project is about the production of deep hole with the aim to produce a chip which is not a continuous chip and also not a powdery chip. These conditions can be attained by varying the spindle speed and the tool feed rate.

Fuzzy Logic in Hole Drilling of Composites

1994 ◽  
Author(s):  
Aditya Thadani ◽  
Athamaram H. Soni
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Thrust Force ◽  
Cutting Speed ◽  
Research Data ◽  
Theoretical Research ◽  
Hole Drilling ◽  
Tool Geometry ◽  
Drilling Process ◽  
And Control

Abstract Experimental and theoretical research data was utilized in building a Fuzzy Logic Controller model applied to simulate the drilling process of composite materials. The objective is to have a better understanding and control of delamination of composites during the drilling process and at the same time to improve the hole finish by controlling fraying and splintering. By controlling the main issues in the drilling process such as feed rate, cutting speed, thrust force, and torque generated in addition to the tool geometry, it is possible to optimize the drilling process avoiding the conventionally encountered problems.

Effects of Hole Pitch to Diameter Ratio P/D of Impingement and Film Hole on Laminated Cooling Effectiveness

2017 ◽  
Author(s):  
Weilun Zhou ◽  
Qinghua Deng ◽  
Wei He ◽  
Zhenping Feng
Keyword(s):  
Mass Flux ◽  
Pressure Loss ◽  
Pressure Ratio ◽  
Diameter Ratio ◽  
Hole Diameter ◽  
Heat Transfer Analysis ◽  
Internal Cooling ◽  
Cooling Effectiveness ◽  
System Pressure ◽  
The Difference

The laminated cooling, also known as impingement-effusion cooling, is believed to be a promising gas turbine blade cooling technique. In this paper, conjugate heat transfer analysis was employed to investigate the overall cooling effectiveness and total pressure loss of the laminated cooling configuration. The pitch to film hole diameter ratio P/Df of 3, 4, 5, 6, combined with pitch to impingement hole diameter ratio P/Di of 4, 6, 8, 10, are studied at the coolant mass flux G of 0.5, 1.0, 1.5, 2.0 kg/(sm2bar) respectively. The results show that overall cooling effectiveness of laminated cooling configuration increases with the decreasing of P/Df and the increasing of the coolant mass flux in general. However P/Df smaller than 3 may leads to a serious blocking in first few film holes at low coolant mass flux. The large P/Di that makes the Mach number of impingement flow greater than 0.16 may cause unacceptable pressure loss. The increment of overall cooling effectiveness depends on the difference between the deterioration of external cooling and the enhancement of internal cooling. Pressure loss increases exponentially with P/Di and G, and it increases more slowly with P/Df that compared to P/Di and G. The mixing loss takes up the most pressure loss at low coolant mass flux. With the increasing of the whole pressure loss, the proportion of throttling loss and laminated loss becomes larger and finally takes up the most of the whole pressure loss. When the sum of throttling loss and laminated loss is greater than mixing loss, the increment of system pressure ratio is unreasonable that compared to the increment of overall cooling effectiveness.

Wet Core Drilling of CFRP with an Electrodeposited Diamond Core Drill - Effects of Cutting Conditions on Chip Evacuation and Core Jamming

2017 ◽  
Vol 749 ◽  
pp. 58-64
Author(s):  
Yuto Kojima ◽  
Ryutaro Tanaka ◽  
Yasuo Yamane ◽  
Katsuhiko Sekiya ◽  
Keiji Yamada
Keyword(s):  
Surface Roughness ◽  
Thrust Force ◽  
Cutting Speed ◽  
Hole Drilling ◽  
Exit Point ◽  
Grain Sizes ◽  
Normal Core ◽  
Tool Shape ◽  
Wet Condition ◽  
On Chip

This study investigated the cutting characteristics of electrodeposited diamond core drill when used to drill a CFRP under wet condition. The effects of different tool shapes, grain sizes and feed rates were examined. A normal core drill, an eccentric with slits core drill (E.S.), and an eccentric with slits and chamfers core drill (E.S.C.) were used. The normal core drill had the shape of a hollow cylinder. The E.S. core drill had the inner cylinder shifted from the center of this tool and slits in the bottom of this tool. The E.S.C. core drill had chamfers on the periphery of this tool. The normal core drill caused severe workpiece core jamming even at 1st hole drilling, and its electro-deposited area was covered entirely by adhered chips. In the case of the E.S. core drill and E.S.C. core drill, the workpiece core did not jam and the thrust force was smaller than that of the normal core drill. The effect of chamfers was little. The E.S.C. core drill with #200 caused smaller surface roughness than that with #100. However, the thrust force was two times larger, and the delamination was observed at the exit point of the hole. In the lower feed rate per revolution the better surface roughness and the lower thrust force were obtained irrespective of the tool shape while the cutting speed showed little effect.

The First Multilateral Well in Eastern Siberia on the Separated Oil Reservoirs

2021 ◽  
Author(s):  
Ruslan Fanisovich Gataullin ◽  
Stanislav Evgen’evich Ter-Saakov ◽  
Evgenij Vladimirovich Nikulin ◽  
Dmitriy Pavlovich Stifeev ◽  
Alexey Vyacheslavovich Filatov
Keyword(s):  
Low Frequency ◽  
Cost Effective ◽  
Drill String ◽  
Hole Drilling ◽  
Drill Bit ◽  
Eastern Siberia ◽  
Water Contact ◽  
Bottom Hole ◽  
Drilling Technology ◽  
Equipment Failures

Abstract This article describes engineering and technology solutions developed to successfully construct unconventional and unique horizontal well at the field of Eastern Siberia targeted to two isolated formations with an option to shut-off top Botuobinsky horizon after gas breakthrough and produce oil from underlying Ulakhansky bed further on. As oil-water contact in the lower part of Ulakhansky horizon makes fracturing the well inexpedient, multi hole drilling technology was implemented enabling drainage of the reserves that are far from the main borehole. The main objective of this well is to deplete Botuobinsky horizon subsequently shutting it off and continuing to recover petroleum reserves from Ulakhansky pay zone. Constructing such well is cost-effective, as it requires drilling only one intermediate casing interval instead of two. Accumulated experience of drilling and completing multi hole wells was used to ensure successful well construction; also, geological and stratigraphic data as well as possible complications while drilling Botuobunsky and Ulakhansky formations were analyzed in-depth. The following appliances were selected to meet the objective: –Bottom-hole equipment enabling drilling abrasive formations under conditions of high vibrations;–Special line of drill bits to ensure high ROP and successful sidetracking without additional tripping;–RSS with 152.4 mm drill bit. The goal set by the operating company was achieved through multi-faceted approach to performing the task, efficient cooperation of engineering technical services and continuous monitoring of output data while drilling. All that combined delivered the results listed below: –Sidetracks were carried out in an open horizontal hole without cement plugs and additional tripping for drill bit or BHA.–Minimized bottom-hole equipment failures under condition of increased high-frequency vibrations from bit while drilling hard formations due to implementation of modular PDM with data-transmitting channel.–Minimized bottom-hole equipment failures under condition of increased low-frequency vibrations from drill string with Hard Bending due to improved BHA design and optimized drilling parameters selection.–Liner was effectively run to Botuobinsky and Ulakhansky reservoirs with an option to shut-off the former after depletion and gas breakthrough. This well is the first one targeted at two isolated formations in East Siberia.

scholarly journals A Novel Manufacturing Technique to Improve Bearing Strength of Pin Loaded Woven Composites

2011 ◽  
Vol 20 (3) ◽  
pp. 096369351102000 ◽  
Author(s):  
Ercan Sevkat ◽  
Malek Brahimi ◽  
Sidi Berri
Keyword(s):  
Failure Modes ◽  
Hole Diameter ◽  
Woven Composites ◽  
Sustained Load ◽  
Hole Drilling ◽  
Geometrical Parameters ◽  
Composite Joints ◽  
Bearing Strength ◽  
Manufacturing Technique ◽  
Glass Fibre Reinforced

The bearing strength of pin-loaded woven glass-fibre reinforced epoxy composites was investigated. As an alternative to the hole-drilling procedure, a novel composite manufacturing technique has been implemented for pin-hole creation. The bearing performance of composite joints manufactured using both techniques was compared. Specimen with various edge- distances to pin-hole diameter ratios (e/d) and, width to pin-hole diameter ratios (w/d) were tested. It was observed that composite joints manufactured using the novel technique sustained more load compared to the joints manufactured by the hole-drilling procedure. Geometrical parameters were found to be effective on failure modes, bearing strength and magnitude of sustained load.

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