IN-PROCESS MEASUREMENT AND NUMERICAL DETERMINATION OF THE TEMPERATURE IN THE CONTACT ZONE DURING SINGLE LIP DEEP HOLE DRILLING

In this presented work, the main objective is the in-process measurement of the thermal as-is state near the drilling contact zone by means of a sensor-integrated tool for single lip deep hole drilling (SLD). Additionally, the mechanical quantities feed force and drilling torque are evaluated. The process monitoring is essential to optimize the surface quality as well as the subsurface properties such as hardness and residual stresses. These quantities are strongly dependent on the thermo-mechanical as-is state in the cutting zone and in the contact zone between the guide pads and the drill hole surface. This contribution gives a project overview including the development of a sensor-integrated single lip deep hole driller for the in-process temperature measurement, the integration of sensor systems in the tool as well as the experimental investigations on the temperature, the feed force and the drilling torque during drilling of a 42CrMo4 steel. The temperature measurement at eleven positions in the driller head provides data to observe the heat generation, distribution, and flow independently from the workpiece characteristics. However, one of the greatest benefits is the non-destructive fashion of the measurement system with their sensor integrated in the tool and thus the reusability. A simulation method, which uses the experimental results as a reference, is used to predict the thermo-mechanical conditions in the contact zone of the drill head and the workpiece. The results of these thermo-mechanical process simulations and the validation of this applied FE approach using the measured quantities are presented, too. The results of this work are 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).

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Temperature monitoring in the subsurface during single lip deep hole drilling

tm - Technisches Messen ◽

10.1515/teme-2020-0055 ◽

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.

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A Study on the Characteristics of Micro Deep Hole Machining Processes

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.364-366.566 ◽

2007 ◽

Vol 364-366 ◽

pp. 566-571

Author(s):

Tae Il Seo ◽

Dong Woo Kim ◽

Myeong Woo Cho ◽

Eung Sug Lee

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

High Speed ◽

Printed Circuit Boards ◽

Hole Drilling ◽

Deep Hole ◽

Machining Processes ◽

Deep Hole Drilling ◽

Micro Drilling ◽

Hole Machining

Recently, the trends of industrial products move towards more miniaturization, variety and mass production. Micro drilling which take high precision in cutting work is required to perform more micro hole and high speed working. Especially, Micro deep hole drilling is becoming more important in a wide spectrum of precision production industries, ranging from the production of automotive fuel injection nozzle, watch and camera parts, medical needles, and thick multilayered Printed Circuit Boards(PCB) that are demanded for very high density electric circuitry. The industries of precision production require smaller holes, high aspect ratio and high speed working for micro deep hole drilling. However the undesirable characteristics of micro drilling is the small signal to noise ratios, wandering motion of drill, high aspect ratio and the increase of cutting force as cutting depth increases. In order to optimize cutting conditions, an experimental study on the characteristics of micro deep hole machining processes using a tool dynamometer was carried out. And additionally, microscope with built-in an inspection monitor showed the relationship between burr in workpieces and chip form of micro drill machining.

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Experimental investigations into electrical discharge deep hole drilling of Inconel 718 using copper-tungsten electrode

International Journal of Mechatronics and Manufacturing Systems ◽

10.1504/ijmms.2012.049969 ◽

2012 ◽

Vol 5 (5/6) ◽

pp. 399 ◽

Cited By ~ 2

Author(s):

P. Kuppan ◽

S. Narayanan ◽

A. Rajadurai

Keyword(s):

Inconel 718 ◽

Electrical Discharge ◽

Hole Drilling ◽

Experimental Investigations ◽

Deep Hole ◽

Tungsten Electrode ◽

Deep Hole Drilling

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Experimental investigations on single-lip deep hole drilling of superalloy Inconel 718 with small diameters

Journal of Manufacturing Processes ◽

10.1016/j.jmapro.2015.06.001 ◽

2015 ◽

Vol 20 ◽

pp. 332-339 ◽

Cited By ~ 23

Author(s):

Dirk Biermann ◽

Marko Kirschner

Keyword(s):

Inconel 718 ◽

Hole Drilling ◽

Experimental Investigations ◽

Deep Hole ◽

Deep Hole Drilling

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Influence of the Cutting Speed and Feed Rate on Torque, Feed Force, Roughness and Shape of the Chips During Deep Hole Drilling

Technological Engineering ◽

10.2478/teen-2013-0013 ◽

2013 ◽

Vol 10 (2) ◽

pp. 11-14

Author(s):

Martin Letavay ◽

M. Laluha ◽

Jozef Pilc

Keyword(s):

Feed Rate ◽

Cutting Forces ◽

Cutting Speed ◽

Hole Drilling ◽

Deep Hole ◽

Deep Hole Drilling ◽

Feed Force ◽

Gun Drill ◽

Steel Grades

Abstract This article describes methodology and realization of the deep hole drilling test. Goal of this trial is to define influence of the cutting speed and feed rate on torque and feed force. As well as during the test here was a focus on roughness and shape of the chips. A gun drill was used for deep hole drilling and we used etalon material, were here is possible to define cutting forces without any further testing of different steel grades. Also there is a description of CNC program, which was used for above mentioned testing and it can be utilized during other different trials.

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

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406214559110 ◽

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.

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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

Thermal Science and Engineering ◽

10.24294/tse.v1i4.874 ◽

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.

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