scholarly journals Experimental and simulative investigation of the oil distribution during a deep-hole drilling process and comparing of the RANS kω-SST and RANS hybrid SAS-SST turbulence model

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Ekrem Oezkaya
Keyword(s):  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Hole Drilling ◽  
Experimental Investigations ◽  
Drilling Process ◽  
Deep Hole ◽  
Deep Drilling ◽  
Deep Hole Drilling ◽  
Sst Model ◽  
Cooling And Lubrication

Helical deep hole drilling is a process frequently used in industrial applications to produce bores with a large length to diameter ratio. For better cooling and lubrication, the deep drilling oil is fed directly into the bore hole via two internal cooling channels. Due to the inaccessibility of the cutting area, experimental investigations that provide information on the actual machining and cooling behavior are difficult to carry out. In this paper, the distribution of the deep drilling oil is investigated both experimentally and simulatively and the results are evaluated. For the Computational Fluid Dynamics (CFD) simulation, two different turbulence models, i.e. the RANS k-ω-SST and hybrid SAS-SST model, are used and compared. Thereby, the actual used deep drilling oil is modelled instead of using fluid dynamic parameters of water, as is often the case. With the hybrid SAS-SST model, the flow could be analyzed much better than with the RANS k-ω-SST model and thus the processes that take place during helical deep drilling could be  simulated with realistic details. Both the experimental and the simulative results show that the deep drilling oil movement is almost exclusively generated by the tool rotation. At the tool’s cutting edges and in the flute, the flow velocity drops to zero for the most part, so that no efficient cooling and lubrication could take place there. In addition, cavitation bubbles form and implode, concluding in the assumption that the process heat is not adequately dissipated and the removal of chips is adversely affected, which in turn can affect the service life of the tool and the bore quality. The carried out investigations show that the application of CFD simulation is an important research instrument in machining technology and that there is still great potential in the area of tool and process optimization.

Whirling vibration of drilling shaft in minimal quantity lubrication deep hole drilling using theoretical and experimental investigation

2014 ◽  
Vol 229 (13) ◽  
pp. 2433-2442
Author(s):  
Lingfei Kong ◽  
Han Niu ◽  
Xiaoli Hou ◽  
Qingfeng Wang
Keyword(s):  
Surface Roughness ◽  
Rotational Speed ◽  
Cutting Fluid ◽  
Hole Drilling ◽  
Experimental Investigations ◽  
Drilling Process ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Minimal Quantity Lubrication ◽  
Minimal Quantity

Under the concept of safety, improving efficiency, or reducing costs in deep hole drilling, the effect of minimal quantity lubrication (MQL) on the dynamic characteristics of drilling shaft is analyzed. A model is presented to describe the pressure function of MQL cutting fluid during drilling process. This model is based on the compressible Reynolds equation in air/oil feature with nonlinearity, and the differential transformation theory is introduced to solve the time-dependent pressure equation satisfied with MQL cutting fluid. Further, with an emphasis on model development, experiments are performed to validate the correctness and effectiveness of the above methods. A series of experimental investigations are carried out on the whirling characteristics of drilling shaft when the rotational speed and drilling depth are changed. Additionally, the vibration trajectories of drilling shaft and the surface roughness of hole are detected under different experimental conditions such as MQL drilling or traditional drilling. The results show that the whirling trajectory of drilling shaft decreases significantly in MQL deep hole drilling but the surface roughness of machined hole is worse due to surface scratches or scales. Nevertheless, there exists an optimal rotational speed of drilling shaft to improve machining precision of hole surface. These results indicate that the MQL method has shown potential to be even more productive as compared to traditional drilling and that the proposed method in this paper can lay a foundation for investigating the dynamic stability of drilling shaft in MQL drilling.

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.

Oberflächenkonditionierung beim Tiefbohren – Teil 2/Surface conditioning during deep drilling

2021 ◽  
Vol 111 (03) ◽  
pp. 118-123
Author(s):  
Andreas Zabel ◽  
Simon Strodick ◽  
Robert Schmidt ◽  
Frank Walther ◽  
Dirk Biermann ◽  
...  
Keyword(s):  
Sensor Technology ◽  
Hole Drilling ◽  
Process Conditions ◽  
Deep Hole ◽  
Process Data ◽  
Deep Drilling ◽  
Deep Hole Drilling ◽  
Surface Conditioning ◽  
Simulation Based

Der Beitrag befasst sich mit Teilaspekten bei der Entwicklung von Methoden zur gezielten, bearbeitungsparallelen Oberflächenkonditionierung beim Tiefbohren. Konkret handelt es sich um messtechnische und simulationsbasierte Ansätze zur Identifikation von thermomechanischen Prozesszuständen beim BTA- und ELB-Verfahren. Hierbei werden Möglichkeiten zur Gewinnung von Prozessdaten sowohl mit einer in-situ eingesetzten Sensorik als auch mit begleitend durchgeführten FEM-Simulationen betrachtet. Diese Daten bilden die Grundlage einer Prozessregelung für die beiden Tiefbohrverfahren. Im zweiten Teil werden nun die Arbeiten und Ergebnisse zum ELB-Tiefbohren behandelt.   The article deals with aspects of developing methods specifically for surface conditioning in deep hole drilling parallel to machining. This involves metrological and simulation-based approaches for identifying thermo-mechanical process conditions in both BTA and ELB process. Ways for obtaining process data both with sensor technology used in-situ and with FEM simulations performed concomitantly are investigated. These data form the basis of a deep hole process control. The second part presents the work and the results on single lip deep hole drilling.

scholarly journals Improved empirical wavelet denoising algorithm with application to whirling detection in deep hole drilling process

Procedia CIRP ◽  
2021 ◽  
Vol 104 ◽  
pp. 1924-1929
Author(s):  
Yue Si ◽  
Xuyang Li ◽  
Lingfei Kong ◽  
Jianming Zhen ◽  
Yan Li
Keyword(s):  
Wavelet Denoising ◽  
Hole Drilling ◽  
Drilling Process ◽  
Deep Hole ◽  
Deep Hole Drilling

The thermal modeling of deep-hole drilling process under MQL condition

2017 ◽  
Vol 29 ◽  
pp. 194-203 ◽  
Author(s):  
A.T. Kuzu ◽  
K. Rahimzadeh Berenji ◽  
B.C. Ekim ◽  
M. Bakkal
Keyword(s):  
Thermal Modeling ◽  
Hole Drilling ◽  
Drilling Process ◽  
Deep Hole ◽  
Deep Hole Drilling

Cutting Mechanism Study on Technology in Near-Dry Deep-Hole Drilling

2010 ◽  
Vol 455 ◽  
pp. 251-256
Author(s):  
Peng Hai ◽  
H.X. Wei
Keyword(s):  
Cutting Fluid ◽  
Hole Drilling ◽  
Deep Hole ◽  
Mechanism Study ◽  
Cutting Mechanism ◽  
Dry Cutting ◽  
Two Phase ◽  
Deep Hole Drilling ◽  
Mathematical Mode ◽  
Cooling And Lubrication

Near-dry deep hole processing technology is a kind of technology which dry cutting technology is applied to deep hole processing to save energy and decrease environmental pollution. In this paper, the structure and work principle of near-dry deep-hole drilling system were introduced and the cutting mechanism of near-dry deep-hole drilling was analyzed which include the mechanism of cutting fluid atomization and flow, the mechanism of atomized cutting fluid cool and lubricate, and the mechanism of separating chips into short pieces and discharge chips by air stream, etc. The mathematical mode of gas-liquid two-phase flow of atomized cutting fluid in drilling shaft and the cooling and lubrication mechanism of the capillary in cutting zone were introduced. It is found that near-dry deep hole processing has better cooling and lubrication effect through experiments.

Sign in / Sign up

Export Citation Format

Share Document