Thermomechanical Impact of the Single-Lip Deep Hole Drilling on the Surface Integrity on the Example of Steel Components

The fatigue behavior of components made of quenched and tempered steel alloys is of elementary importance, especially in the automotive industry. To a great extent, the components’ fatigue strength is influenced by the surface integrity properties. For machined components, the generated surface is often exposed to the highest thermomechanical loads, potentially resulting in transformations of the subsurface microstructure and hardness as well as the residual stress state. While the measurement of the mechanical load using dynamometers is well established, in-process temperature measurements are challenging, especially for drilling processes due to the process kinematics and the difficult to access cutting zone. To access the impact of the thermomechanical load during the single-lip drilling process on the produced surface integrity, an in-process measurement was developed and applied for different cutting parameters. By using a two-color pyrometer for temperature measurements at the tool’s cutting edge in combination with a dynamometer for measuring the occurring force and torque, the influence of different cutting parameter variations on the thermomechanical impact on the bore surface are evaluated. By correlating force and temperature values with the resultant surface integrity, a range of process parameters can be determined in which the highest dynamic strength of the samples is expected. Thermally induced defects, such as the formation of white etching layers (WEL), can be avoided by the exact identification of critical parameter combinations whereas a mechanically induced microstructure refinement and the induction of residual compressive stresses in the subsurface zone is targeted. Further, eddy-current analysis as a non-destructive method for surface integrity evaluation is used for the characterization of the surface integrity properties.

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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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Influence of cutting parameters on the formation of white etching layers in BTA deep hole drilling

tm - Technisches Messen ◽

10.1515/teme-2020-0046 ◽

2020 ◽

Vol 87 (11) ◽

pp. 674-682

Author(s):

Simon Strodick ◽

Kai Berteld ◽

Robert Schmidt ◽

Dirk Biermann ◽

Andreas Zabel ◽

...

Keyword(s):

Surface Integrity ◽

Cutting Speed ◽

Cutting Parameters ◽

Substrate Material ◽

Hole Drilling ◽

Deep Hole ◽

Deep Hole Drilling ◽

Aisi 4140 ◽

High Feed ◽

Subsurface Zones

AbstractIn this study, the influence of cutting speed and feed rate on surface integrity in Boring Trepanning Association (BTA) deep hole drilling of AISI 4140+QT is investigated. Microstructure and micro-hardness in the subsurface zones of bores are analyzed, using metallographic and micromagnetic methods. It was found that when using high feed rates and cutting speeds, white etching layers (WEL) form at the surface of the bores. These layers are up to three times harder than the substrate material and have a maximum thickness of approx. {t_{\mathrm{WEL}}}\approx 12\hspace{0.1667em}\text{\textmu m}. WEL were usually followed by a transitional layer, so that elevated hardness was observed until a depth of {d_{\mathrm{surf}}}=35\hspace{0.1667em}\text{\textmu m} below the surface. Magnetic Barkhausen noise (MBN) analysis proved to be applicable for the fast and reliable detection of WEL. The presented results contribute to gaining a deeper understanding of the complex interrelations between the design of the BTA process, the resulting microstructure in the machined component and the properties of the conditioned surface. Based on discovered correlations, a dynamic process control will be developed for BTA deep hole drilling, which will allow reliably tailoring surface integrity of components to specific demands, like an optimized fatigue performance.

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WEAR TESTING OF BUTTONS IN BITS FOR BLASTHOLE DRILLING

Tribologia ◽

10.5604/01.3001.0012.6954 ◽

2018 ◽

Vol 278 (2) ◽

pp. 13-19 ◽

Cited By ~ 1

Author(s):

Rafał DUDEK ◽

Krzysztof WŁADZIELCZYK

Keyword(s):

Abrasive Wear ◽

Blast Hole ◽

Operating Time ◽

Operating Conditions ◽

Wear Testing ◽

Hole Drilling ◽

Drilling Process ◽

Rock Mining ◽

Drilling Rigs ◽

The Impact

The article presents the results of the wear testing of buttons in selected types of bits with the diameter of 95 mm used for blast hole drilling in a rock mining. The purpose of the testing was to determine the type of the wear of peripheral and frontal buttons in the actual operating conditions of bits and the impact of selected parameters of the drilling process and of sharpening the buttons on their durability. Tests of button wear were carried out by the blasthole drilling in deposits of the Devonian and Triassic dolomites. For the blast hole drilling with tested bits, drilling rigs HSB 500 and HBM 60, equipped with down-the-hole impact mechanisms VKP 95-2 from the company Permon were used. Tests on the wear of buttons were carried out according to the adopted methodology, taking into account both their abrasive wear and wear through crushing or falling out. During the drilling of holes, every effort was made to use fixed values of parameters of the drilling process, except for the value of drill stem rotation speed, because one of objectives of the research was to determine its impact on the abrasive wear of tested bits buttons. The obtained results of tests proved that the predominant type of wear of button bits for blast hole drilling is an abrasive wear of frontal buttons, and regular sharpening of the buttons allows increasing the operating time of rock bits by up to 35%.

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Application and Technology Research in Deep-Hole Drilling System

Materials Science Forum ◽

10.4028/www.scientific.net/msf.800-801.506 ◽

2014 ◽

Vol 800-801 ◽

pp. 506-510

Author(s):

Hai Yan You ◽

Shu Cai Yang ◽

Cai Xu Yue ◽

Xue Feng Wu ◽

Yang Xie

Keyword(s):

Cutting Speed ◽

High Hardness ◽

High Strength ◽

Cutting Parameters ◽

Hole Drilling ◽

Drilling Process ◽

Deep Hole ◽

Deep Hole Drilling ◽

Chip Breaking ◽

Content Selection

With the new type of high strength , high hardness difficult machining parts appear constantly, both for the quality of deep processing, durability of the tools, or reliability of the drilling systems are putting forward higher requirements. This paper mainly describes the characteristics of deep-hole drilling systems and applications, and content selection of cutting parameters, impact of cutting speed and feed rate for chip breaking and so do some explanation, These have certain guiding significance for chip breaking can get better. Finally, introduce the deep-hole drilling in the drilling process causes common problems and solutions, to provide some references for practical manufacture process.

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A Study on Drilling High-Strength CFRP Laminates: Frictional Heat and Cutting Temperature

Materials ◽

10.3390/ma11122366 ◽

2018 ◽

Vol 11 (12) ◽

pp. 2366 ◽

Cited By ~ 8

Author(s):

Jinyang Xu ◽

Chao Li ◽

Jiaqiang Dang ◽

Mohamed El Mansori ◽

Fei Ren

Keyword(s):

Elastic Recovery ◽

Dominant Role ◽

Cutting Temperature ◽

High Strength ◽

Cutting Parameters ◽

Vital Role ◽

Frictional Heat ◽

Drilling Process ◽

Friction Behavior ◽

The Impact

High-strength carbon fiber reinforced polymer (CFRP) composites have become popular materials to be utilized in the aerospace and automotive industries, due to their unique and superior mechanical properties. An understanding of cutting temperatures is rather important when dealing with high-strength CFRPs, since machining defects are likely to occur because of high temperatures (especially in the semi-closed drilling process). The friction behavior at the flank tool-workpiece interface when drilling CFRPs plays a vital role in the heat generation, which still remains poorly understood. The aim of this paper is to address the friction-induced heat based on two specially-designed tribometers to simulate different sliding velocities, similar to those occurring along the flank tool-work interface in drilling. The elastic recovery effect during the drilling process was considered during the tribo-drilling experiments. The drilling temperatures were calculated by the analytical model and verified by the in-situ experimental results gained using the embedded thermocouples into the drills. The results indicate that the magnitudes of the interfacial friction coefficients between the cemented carbide tool and the CFRP specimen are within the range between 0.135–0.168 under the examined conditions. Additionally, the friction caused by the plastic deformation and elastic recovery effects plays a dominant role when the sliding velocity increases. The findings in this paper point out the impact of the friction-induced heat and cutting parameters on the overall drilling temperature.

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Experimental Study on Ultrasonic Vibration Drilling of Titanium Alloy Micro-Hole

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.588-589.1877 ◽

2012 ◽

Vol 588-589 ◽

pp. 1877-1880 ◽

Cited By ~ 1

Author(s):

Zhan Feng Liu ◽

Huan Chang Zhang

Keyword(s):

Titanium Alloy ◽

Ultrasonic Vibration ◽

Cutting Parameters ◽

Hole Drilling ◽

Drilling Process ◽

Basic Principles ◽

Actual Structure ◽

Tc4 Titanium Alloy ◽

Micro Hole ◽

Vibration Drilling

Through the analysis of the basic principles of vibration drilling and vibration drilling process, in the drilling device and the cutting parameter sides , combined with the actual structure of the workpiece as well as the ultrasonic vibration drilling processing methods to elaborate, using the ultrasonic vibration drilling device to carry out the TC4 titanium alloy micro-hole drilling test. The test prove that selecting reasonable cutting parameters can solve the problem of drillingTC4 titanium alloy micro-hole that size is Φ1.5mm × 12mm , fully reflects the superiority of the ultrasonic vibration drilling. A new method was afforded for titanium alloy micro-hole drilling.

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Weak Signal Enhancement For Small Drill Condition Monitoring In PCB Drilling Process By Using Adaptive Multistable Stochastic Resonance

10.21203/rs.3.rs-965549/v1 ◽

2021 ◽

Author(s):

Qifeng Tan ◽

Guodong Liu ◽

Yong Li ◽

Hao Tong

Keyword(s):

Tool Wear ◽

Stochastic Resonance ◽

Condition Monitoring ◽

Printed Circuit Boards ◽

Hole Drilling ◽

Drilling Process ◽

Weak Signal ◽

Weak Signals ◽

The Impact ◽

Sr Method

Abstract The on-line tool condition monitoring is demanded to detect the tool wear and to ensure the hole drilling process of printed circuit boards (PCB) goes on smoothly. However, due to the impact of ambient noise caused by the limited size of small drill and the laminated material of PCB, the tool wear signal features are too weak to extract. The stochastic resonance (SR) method has been proven to be effective in enhancing weak signals among various weak signal extraction. In this paper, an adaptive multistable stochastic resonance is presented to improve performance of the SR method and process the tool wear signals for PCB drilling. The differential evolution (DE) algorithm is applied to adaptively optimize potential parameters and compensation factor, which makes the SR method suitable for high frequency signal. Moreover, tool wear experiments with different drill wear are carried out to verify the effectiveness of the proposed method. The results indicate that the proposed method improves the signal-to-noise ratio and has great potential in enhancing weak signals for small drill condition monitoring in PCB drilling process.

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Analysis of the Machinability of Carbon Fiber Composite Materials in Function of Tool Wear and Cutting Parameters Using the Artificial Neural Network Approach

Materials ◽

10.3390/ma12172747 ◽

2019 ◽

Vol 12 (17) ◽

pp. 2747 ◽

Cited By ~ 1

Author(s):

Norberto Feito ◽

Ana Muñoz-Sánchez ◽

Antonio Díaz-Álvarez ◽

José Antonio Loya

Keyword(s):

Neural Network ◽

Artificial Neural Network ◽

Composite Materials ◽

Carbon Fiber ◽

Tool Wear ◽

Thrust Force ◽

Cutting Parameters ◽

Drilling Process ◽

Artificial Neural ◽

The Impact

Local delamination is the most undesirable damage associated with drilling carbon fiber reinforced composite materials (CFRPs). This defect reduces the structural integrity of the material, which affects the residual strength of the assembled components. A positive correlation between delamination extension and thrust force during the drilling process is reported in literature. The abrasive effect of the carbon fibers modifies the geometry of the fresh tool, which increases the thrust force and, in consequence, the induced damage in the workpiece. Using a control system based on an artificial neural network (ANN), an analysis of the influence of the tool wear in the thrust force during the drilling of CFRP laminate to reduce the damage is developed. The spindle speed, feed rate, and drill point angle are also included as input parameters of the study. The training and testing of the ANN model are carried out with experimental drilling tests using uncoated carbide helicoidal tools. The data were trained using error-back propagation-training algorithm (EBPTA). The use of the neural network rapidly provides results of the thrust force evolution in function of the tool wear and cutting parameters. The obtained results can be used by the industry as a guide to control the impact of the wear of the tool in the quality of the finished workpiece.

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Investigation of the Impact of Cutting Parameters on Surface Integrity in the End Milling of Inconel 625

Materials Science Forum ◽

10.4028/www.scientific.net/msf.969.762 ◽

2019 ◽

Vol 969 ◽

pp. 762-767 ◽

Cited By ~ 2

Author(s):

Ramesh Rajguru ◽

Hari Vasudevan

Keyword(s):

Residual Stresses ◽

Surface Integrity ◽

Cutting Parameters ◽

Rake Angle ◽

Inconel 625 ◽

Micro Hardness ◽

Machined Surface ◽

Radial Rake Angle ◽

Radial Depth ◽

The Impact

Nickel based super alloys, such as Inconel 625 is amongst the most difficult to machine, due to its low thermal conductivity and high strength at higher temperature. Although, they are used in aerospace exhaust systems and other applications, the strain hardening that results during the machining operation, which adversely affects surface integrity of machined surface of such materials especially in extensive applications, is a cause for concern. In this context, this study was carried out, involving the milling operation, using solid carbide tools coated with TiAlSiN, under specifically developed conditions for dry machining of the difficult to cut materials. The cutting parameters were 4 in number, namely radial rake angle, feed per tooth, cutting speed and radial depth of cut and the response parameters included surface integrity characteristics, such as residual stresses, surface roughness and micro-hardness. Based on the experimental analyses, it was found that the micro-hardness of machined surface was higher. Micro hardness of sub surface decreases with the depth (50,100,150,250μm) due to a reduction in the work hardening of the Inconel 625, underneath the surface layer. The residual stresses were analyzed using main effect plot, and it was seen that the residual stresses were significantly influenced by the radial rake angle, followed by feed per tooth.

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