Control of Chip Formation and Improved Chip Ejection in Drilling With Modulation-Assisted Machining

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Yang Guo ◽  
James B. Mann
Keyword(s):  
Chip Formation ◽  
Kinematic Model ◽  
Low Frequency ◽  
Hole Drilling ◽  
Drilling Process ◽  
Low Frequency Oscillation ◽  
Thin Sections ◽  
Gun Drill ◽  
Chip Size ◽  
Cutting Regimes

Abstract Drilling with modulation-assisted machining (MAM) superimposes a low-frequency oscillation onto the drill feed motion. The otherwise continuous cutting in the drilling process is converted into a series of discrete cutting events. The result is a discrete chip formation process and concurrent improvement in chip ejection. The discrete chip formation and ejection in drilling with MAM were investigated via systematic experiments in OFHC Cu and Ti6Al4V using a two-flute twist drill and a single-flute gun drill. Drilling thrust force and chip morphologies for various modulation conditions are examined. The continuous cutting and discrete cutting regimes of modulation-assisted drilling are compared with conditions determined by a kinematic model. The results show that chip formation in the continuous cutting regime with MAM can influence chip breakage by random fracture at thin sections of the chip, but in this regime the resulting chip size is variable and not controlled. In contrast, when MAM conditions operate in the regime of discrete cutting, the deformed chip size can be directly controlled. The ability to control the chip size improves chip ejection and drilling process stability. A set of modulation conditions for enhanced performance of chip ejection are proposed. The study shows that modulation-assisted machining offers distinct advantages as a method for deep-hole drilling applications.

Experimental Evaluation of Cutting Kinematics and Chip Evacuation in Drilling With Low-Frequency Modulation-Assisted Machining

2017 ◽  
Author(s):  
Yang Guo ◽  
James B. Mann
Keyword(s):  
Kinematic Model ◽  
Low Frequency ◽  
Chip Morphology ◽  
Process Efficiency ◽  
Low Frequency Oscillation ◽  
Gun Drill ◽  
Chip Size ◽  
Cutting Kinematics ◽  
Cutting Regimes ◽  
Intermittent Cutting

Modulation assisted machining (MAM) superimposes a low-frequency oscillation onto the cutting process. The otherwise continuous cutting is transformed into a series of discrete, intermittent cutting events. A primary benefit of this process is to form discrete chips of small sizes and hence to improve chip evacuation. For applications in drilling the ability to control the chip size offers a direct route to improving process efficiency and stability. In this paper, the MAM process is evaluated for drilling applications via systematic experiments in drilling copper and Ti6Al4V with a two-flute twist drill and a single-flute gun drill. Based on the measurement of thrust force and examination of chip morphology, the continuous cutting and intermittent cutting regimes of MAM are determined experimentally in the normalized frequency and amplitude parameter space. The results are compared with those predicted by the kinematic model of MAM. Furthermore, the results clearly demonstrate the effect of chip morphology control on chip evacuation and process stability in drilling. The modulation conditions leading to the best performance in chip evacuation are discussed. The study shows that MAM is a promising process for enhancing the efficiency and stability in drilling difficult-to-cut materials and/or holes with high length-to-diameter ratio.

Research of Machining Process on 17-4PH Stainless Steel Superfine Deep-Hole Drilling

2014 ◽  
Vol 633-634 ◽  
pp. 688-692 ◽  
Author(s):  
Zhan Feng Liu ◽  
Han Chen Wang
Keyword(s):  
Stainless Steel ◽  
Wall Thickness ◽  
Machining Process ◽  
New Method ◽  
Hole Drilling ◽  
Drilling Process ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Gun Drill

Through the analysis of superfine deep-hole drilling process, we used the combination of gun drill and BTA deep-hole drilling process for 17-4PH (0Cr17Ni4Cu4Nb) stainless steel deep-hole drilling test. We measured wall thickness point by point, and calculated the conversion of the eccentricity in a deviation axis line. Which fully embodies the advantage of this process for stainless steel 17-4PH, and provides a new method in super hardness material deep-hole drilling field.

scholarly journals The system for adaptive control of axial tool oscillations in vibratory drilling: description and experimental study

2021 ◽  
Author(s):  
Ilya Ivanov ◽  
Sergey A. Voronov ◽  
Igor A. Kiselev
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Dynamic Properties ◽  
Low Frequency ◽  
Hole Drilling ◽  
Feedback Gain ◽  
Drilling Process ◽  
Additional Energy ◽  
Cutting Zone ◽  
Vibration Drilling

Abstract Reliable segmentation and evacuation of chips from the cutting zone are essential for effective deep hole drilling. Drilling with low-frequency axial vibrations ensures these useful effects because cutting edges periodically leave the cutting zone. Useful tool vibrations can be maintained by using a special self-vibratory drilling head. The drilling head has an elastic element and ensures the self-excitation of vibrations due to the regenerative effect. However, high damping in the cutting zone suppresses axial self-vibrations and renders such a drilling head inexpedient for the industry. In this study, a novel system of adaptive control of the vibration drilling process was developed. The control objective is to maintain a specified peak-to-peak (PTP) value of vibration displacements. Due to in-process adaptation of the feedback gain, the control system supplies additional energy if vibrations are not self-excited and removes energy if the PTP vibration displacements are greater than the specified value. To test the workability of the system, an experimental setup was made. In the setup, the actuator force acts on an elastically fixed workpiece. The dynamic properties of the setup are equivalent to those of the vibration drilling head. The algorithm of feedback gain adaptation was implemented with a microcontroller. A number of experiments for different drilling regimes revealed that the control system successfully maintains the specified PTP value of displacements. The developed control system can be implemented on a vibration drilling head because only an accelerometer is required for control and the required actuator force is under 100 N.

ANALYSIS OF STAND RESEARCH RESULTS OF AXIAL DYNAMIC FORCE IN DRILLING BY THREE ROLLER CONE BIT

2019 ◽  
pp. 81-93
Author(s):  
В. М. Мойсишин ◽  
M. V. Lyskanych ◽  
R. A. Zhovniruk ◽  
Ye. P. Majkovych
Keyword(s):  
Low Frequency ◽  
Maximum Energy ◽  
Dynamic Force ◽  
Low Frequency Oscillation ◽  
Drilling Tool ◽  
Rock Destruction ◽  
Frequency Components ◽  
Harmonic Components ◽  
Experimental Values ◽  
Harmful Effects

The purpose of the proposed article is to establish the causes of oscillations of drilling tool and the basic laws of the distribution of the total energy of the process of changing the axial dynamic force over frequencies of spectrum. Variable factors during experiments on the classical plan were the rigidity of drilling tool and the hardness of the rock. According to the results of research, the main power of the process of change of axial dynamic force during drilling of three roller cone bits is in the frequency range 0-32 Hz in which three harmonic frequency components are allocated which correspond to the theoretical values of low-frequency and gear oscillations of the chisel and proper oscillations of the bit. The experimental values of frequencies of harmonic components of energy and normalized spectrum as well as the magnitude of the dispersion of the axial dynamic force and its normalized values at these frequencies are presented. It has been found that with decreasing rigidity of the drilling tool maximum energy of axial dynamic force moves from the low-frequency oscillation region to the tooth oscillation area, intensifying the process of rock destruction and, at the same time, protecting the tool from the harmful effects of the vibrations of the bit. Reducing the rigidity of the drilling tool protects the bit from the harmful effects of the vibrations generated by the stand. The energy reductions in these fluctuations range from 47 to 77%.

PENGEMBANGAN ALAT UKUR COMPRESSION TESTER

2019 ◽  
Vol 3 (2) ◽  
pp. 111-118
Author(s):  
Bahtiar Wilantara ◽  
Raharjo Raharjo
Keyword(s):  
Pressure Gauge ◽  
Welding Process ◽  
Field Trials ◽  
Ease Of Use ◽  
Hole Drilling ◽  
Measurement Tool ◽  
Drilling Process ◽  
Measuring Instrument ◽  
Digital Compression ◽  
Materials Used

This study aims to develop an analog compression tester measuring instrument into a digital compression tester as a measurement tool that can provide effectiveness and efficiency to users.                     This research is a research and development or R&D. This research was conducted in several steps, namely: problem identification, information gathering, product design, product manufacture, expert validation, product revision, testing, final production. The development of analog compression tester was first validated by material experts, media experts, and 15 students, and 5 students for field trials. The subjects of this study were vocational students at Taman Karya Madya Teknik Kebumen. Data collection techniques used in this study using instruments in the form of a questionnaire. The data analysis technique of this research is descriptive qualitative and quantitative descriptive percentage.                 The results of the development of digital compression tester designs are: 1) the tools and materials used are electric drill, grinding, cutter, goggles, gloves, masks, ruler, acetaminine welding, screwdriver, scissors, digital dial pressure gauge, hose, spark plugs, clamps , and nepel, 2) the manufacturing process that starts from the cutting process, the hole drilling process, the welding process and the process of connecting between components, 3) the workings of digital compression tester design that is reading the pressure or compression of the machine displayed on the monitor digitally using dial pressure digital gauge, 4) the test results obtained from the validation results from: a) material experts at 89% or Eligible; b) media experts at 85% or reasonable; c) response of field trial students in terms of ease of use and reading of 90% or feasible. Thus, the conclusion that the digital compression tester measuring instrument declared feasible to use for measurement.

scholarly journals Temperature monitoring in the subsurface during single lip deep hole drilling

2020 ◽  
Vol 87 (12) ◽  
pp. 757-767
Author(s):  
Robert Wegert ◽  
Vinzenz Guski ◽  
Hans-Christian Möhring ◽  
Siegfried Schmauder
Keyword(s):  
Cutting Parameters ◽  
Drill Hole ◽  
Machining Process ◽  
Hole Drilling ◽  
Drilling Process ◽  
Deep Hole ◽  
Machining Processes ◽  
Deep Hole Drilling ◽  
Feed Force ◽  
Cutting Zone

AbstractThe surface quality and the subsurface properties such as hardness, residual stresses and grain size of a drill hole are dependent on the cutting parameters of the single lip deep hole drilling process and therefore on the thermomechanical as-is state in the cutting zone and in the contact zone between the guide pads and the drill hole surface. In this contribution, the main objectives are the in-process measurement of the thermal as-is state in the subsurface of a drilling hole by means of thermocouples as well as the feed force and drilling torque evaluation. FE simulation results to verify the investigations and to predict the thermomechanical conditions in the cutting zone are presented as well. The work is part of an interdisciplinary research project in the framework of the priority program “Surface Conditioning in Machining Processes” (SPP 2086) of the German Research Foundation (DFG).This contribution provides an overview of the effects of cutting parameters, cooling lubrication and including wear on the thermal conditions in the subsurface and mechanical loads during this machining process. At first, a test set up for the in-process temperature measurement will be presented with the execution as well as the analysis of the resulting temperature, feed force and drilling torque during drilling a 42CrMo4 steel. Furthermore, the results of process simulations and the validation of this applied FE approach with measured quantities are presented.

Low-frequency-oscillation characteristics of ionization distribution in Hall thruster channels

Vacuum ◽  
2021 ◽  
pp. 110320
Author(s):  
Tianyuan Ji ◽  
Liqiu Wei ◽  
Haifeng Lu ◽  
Shangmin Wang ◽  
Ning Guo ◽  
...  
Keyword(s):  
Low Frequency ◽  
Hall Thruster ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
Oscillation Characteristics
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