scholarly journals Experimental Investigation of Suitable Cutting Conditions of Dry Drilling into High-Strength Structural Steel

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4381
Author(s):  
Lukáš Pelikán ◽  
Michal Slaný ◽  
Libor Beránek ◽  
Vladislav Andronov ◽  
Martin Nečas ◽  
...  

Dry machining is one of the main ways to reduce the environmental burden of the machining process and reduce the negative effect of the cutting fluid and aerosols on operators. In addition, dry machining can reduce overall machining costs and, in the case of large workpieces, reduce the extra work associated with removing residual cutting fluid from the workpiece and adjacent area. For high-strength structural steel products, it is typical to drill holes with larger diameters of around 20 mm. Therefore, this work is devoted to the investigation of the dry drilling process carried out on a workpiece made of S960QL steel with a helical drill with a diameter of 21 mm. The aim was to find suitable cutting conditions for dry drilling with regard to process stability and workpiece quality. An experiment performed with a coolant served as a comparison base. A dry drilling experiment was performed with cutting speeds from 30 to 70 m·min−1 and feeds from 0.1 to 0.3 mm·rev−1, and with the results of this experiment, the same experiment with flood cooling was performed. During the drilling process, spindle torque values were recorded using the indirect spindle current recording method. The macroscopic chip morphology was studied to understand the cutting process. The chip thickness ratio was measured, as well as the maximum diameter of spiral chips. On the final workpiece, the qualitative and dimensional parameters of the holes were evaluated, such as the diameter, cylindricity and surface roughness, depending on the change in the cutting conditions and cutting environment. Evaluation of the obtained data led to the following conclusions. When drilling the S960QL material, there is only a very small increase in the drilling torque during dry drilling compared to drilling with cutting fluid. The increase in friction demonstrated by the chip thickness coefficient is significant. The influence of the environment on the dimensional accuracy showed a tendency for a slight increase in the holes’ diameters during dry machining. In comparison, the cylindricity of the dry-drilled holes shows a lower deviation than the holes drilled with cutting fluid. The surface roughness of the holes after dry drilling is affected by the increased friction of the outgoing chips, despite the resulting parameters being very good due to the drilling technology standards. This work provides a comprehensive view of the dry drilling process under defined conditions, and the results represent suitable cutting conditions to achieve a stable cutting process and a suitable quality of drilled holes.

Author(s):  
Stephen A. Batzer ◽  
Alexander M. Gouskov ◽  
Sergey A. Voronov

Abstract The dynamic behavior of deep-hole vibratory drilling is analyzed. The mathematical model presented allows the determination of axial tool and workpiece displacements and cutting forces for significant dynamic system behavior such as the entrance of the cutting tool into workpiece material and exit. Model parameters include the actual rigidity of the tool and workpiece, time-varying chip thickness, time lag for chip formation due to tool rotation and possible disengagement of drill cutting edges from the workpiece due to tool and/or workpiece axial vibrations. The main features of this model are its nonlinearity and inclusion of time lag differential equations which require numeric solutions. The specific cutting conditions (feed, tool rotational velocity, amplitude and frequency of forced vibrations) necessary to obtain discontinuous chips and reliable removal are determined. The stability conditions of excited vibrations are also investigated. Calculated bifurcation diagrams make it possible to derive the domain of system parameters along with the determination of optimal cutting conditions.


2019 ◽  
Vol 105 (5-6) ◽  
pp. 2151-2165 ◽  
Author(s):  
Adel Taha Abbas ◽  
Danil Yurievich Pimenov ◽  
Ivan Nikolaevich Erdakov ◽  
Tadeusz Mikolajczyk ◽  
Mahmoud Sayed Soliman ◽  
...  

Abstract Computer Numerical Control (CNC) face milling is commonly used to manufacture products from high-strength grade-H steel in both the automotive and the construction industry. The various milling operations for these components have key performance indicators: accuracy, surface roughness (Ra), and machining time for removal of a unit volume min/cm3 (Tm). The specified surface roughness values for machining each component is achieved based on the prototype specifications. However, poor adherence to specifications can result in the rejection of the machined parts, implying extra production costs and raw material wastage. An algorithm using an artificial neural network (ANN) with the Edgeworth-Pareto method is presented in this paper to optimize the cutting parameter in CNC face-milling operations. The set of parameters are adjusted to improve surface roughness and minimal unit-volume material removal rates, thereby reducing production costs and improving accuracy. An ANN algorithm is designed in Matlab, based on a 3–10-1 Multi-Layer Perceptron (MLP), which predicts the Ra of the workpiece surface to an accuracy of ± 5.78% within the range of the experimental angular spindle speed, feed rate, and cutting depth. An unprecedented Pareto frontier for Ra and Tm was obtained for the finished grade-H steel workpiece using an ANN algorithm that was then used to determine optimized cutting conditions. Depending on the production objective, one or the other of two sets of optimum machining conditions can be used: the first one sets a minimum cutting power, while the other sets a maximum Tm with a slight increase (under 5%) in milling costs.


2014 ◽  
Vol 30 (6) ◽  
pp. 667-678 ◽  
Author(s):  
S. Kouravand ◽  
B. M. Imani ◽  
J. Ni

AbstractMicro milling operation is a fabrication process to create 3D parts from tens of micrometers to a few millimeters in size using a tool with diameter less than 1mm. Micro groove is one of the common features observed in the micro parts. The surface roughness of micro grooves plays an important role in their performance. Since most of the finishing processes could not be easily performed on the micro grooves, it is of extreme importance to find a relationship between micro milling parameters and the surface roughness profile. In this paper, in order to anticipate the profile and surface roughness of the groove floor a model is proposed based on the kinematic of cutting process and tool geometry. The effects of minimum chip thickness, elastic recovery, size effect and tool deflection are included in the model. Relationship between position of points on the floor surface of groove and kinematics of cutting process are derived. In next step, simulations of proposed model are performed in the ACIS environment. Finally, using the DOE method surface roughness is investigated stochastically. The simulated and measured surface roughnesses are compared together that confirm the validity of proposed model.


2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
S. Turchetta

Stone machining by diamond disk is a widespread process to manufacture standard products, such as tiles, slabs, and kerbs. Cutting force and energy may be used to monitor stone machining. Empirical models are required to guide the selection of cutting conditions. In this paper, the effects of cutting conditions on cutting force and cutting energy are related to the shape of the idealized chip thickness. The empirical models developed in this paper can be used to predict the variation of the cutting energy. Therefore these models can be used to guide the selection of cutting conditions. The chip generation and removal process has been quantified with the intention of assisting both the toolmaker and the stonemason in optimising the tool composition and cutting process parameters, respectively.


2006 ◽  
Vol 532-533 ◽  
pp. 753-756 ◽  
Author(s):  
Jun Zhao ◽  
Xing Ai ◽  
Zuo Li Li

The Finite Element Method (FEM) has proven to be an effective technique to investigate cutting process so as to improve cutting tool design and select optimum cutting conditions. The present work focuses on the FEM simulation of cutting forces in high speed cutting by using an orthogonal cutting model with variant undeformed chip thickness under plane-strain condition to mimic intermittent cutting process such as milling. High speed cutting of 45%C steel using uncoated carbide tools are simulated as the application of the proposed model. The updated Lagrangian formulation is adopted in the dynamic FEM simulation in which the normalized Cockroft and Latham damage criterion is used as the ductile fracture criterion. The simulation results of cutting force components under different cutting conditions show that both the thrust cutting force and the tangential cutting force increase with the increase in undeformed chip thickness or feed rate, whereas decrease with the increase in cutting speed. Some important aspects of modeling the high speed cutting are discussed as well to expect the future work in FEM simulation.


Author(s):  
Mostafa A. Abdullah  , Ahmed B. Abdulwahhab   ,   Atheer R.

In the curents study aimed to assess the effects of cutting conditions  (spindle speed, feed rate, tool diameter) parameters as input impact on material removal rate (MRR) and surface roughness (Ra) as output of steel (AISI 1015). A number of drilling experiments were conducted using the L9 orthogonal array on conventional drilling machine with use feed rate (0.038,0.076,0.203) mm/rev and spindle speed (132,550,930) rpm and tool diameter (11,15,20) mm HSS twist drills under dry cutting conditions. Analysis of variance (ANOVA) was employed to determine the most significant control factors affecting on surface roughness and MRR. The result shown the tool diameter the important factor effect with (64.08%) and (76.12%) on MRR and surface roughness respectively.


2018 ◽  
Vol 80 (6) ◽  
Author(s):  
Sunil Kumar ◽  
Dilbag Singh ◽  
Nirmal Singh Kalsi

From the last decade, the use of high corrosion resistance, high strength superalloys (mostly Ni- or Ti-based) at elevated temperature have significantly increased in aerospace or transport industry. Such materials are tremendously difficult to cut, develop a high temperature and deteriorate the quality of the components leading to tool wear. In place of using the cutting fluid, strict environmental limit develops new cutting methods or techniques for enhancing the tool life. This study demonstrates the performance of solid lubricants (hexagonal boron nitride and graphite) on surface quality. Tool geometry and cutting variables were selected for machining Inconel 718 with TiAlN-coated carbide inserts. The comparison has been conducted between solid lubricant assistant machining and dry machining. The studies demonstrate that the performance of solid lubricants is better than dry machining. There is 10% to 18% reduction in surface roughness with solid lubricants as compared to dry machining.


2015 ◽  
Vol 799-800 ◽  
pp. 247-250 ◽  
Author(s):  
M.A. Fairuz ◽  
M.J. Nurul Adlina ◽  
Azwan Iskandar Azmi ◽  
M.R.M. Hafiezal ◽  
K.W. Leong

Cutting fluid is a well-known as one of an important element in machining process. However, the consumption of mineral oils as cutting fluid has been raising concern due to worldwide interest in environmental and health matters. The application of vegetable-oil based lubricant is seen can overcome the problem but requires a research study about the machinability. This research paper represents the machinability of using several possible vegetable oils as cutting fluid in term of chip formation and tool wear during drilling operation on stainless steel, AISI 316. In particular, the performance of the vegetable oils; palm, sesame, olive and coconut oils were compared under minimum quantity lubrication (MQL) technique. The result reported that the coconut oil indicates the best machinability in term of highest and uniform chip thickness and least wear on the drill bit under same condition with others. These performances are followed by palm, olive and sesame oil. In additional, the viscosity measurement indicates that coconut oil has the lowest value which can possesses better fluidity and faster cooling capacity than other oils. Overall, coconut oil is recommended as viable alternative lubricants during drilling of stainless steel.


2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Sulaiman Abdulkareem ◽  
Moshood A Babatunde ◽  
Temitayo S Ogedengbe ◽  
Isaac K Adegun

Cutting fluids are used to reduce heat generated during machining, however some have been discovered to pose health challenges hence the search for viable alternatives. In this paper, three machining conditions (dry machining, wet machining with soluble oil and wet machining with used-engine oil) were conducted on high carbon steel, with a sole aim of investigating the suitability of engine oil as an alternative to soluble oil. Measurements related to effective use of oil as metal cutting fluids were determined and the machining parameters used were cutting speed (750 – 1750 rpm), feed rate (40 – 120 mm/rev), and depth of cut (0.1 – 0.3 mm). The experimental procedure was formulated using Minitab software version 18 and the machining responses investigated were maximum temperature at the cutting interface, surface roughness, and tool wear rate (TWR). Thermodynamic properties investigated include, flashpoint, specific heat capacity, viscosity and density. The experimental results showed that cutting temperature reduced from an average of 440oK during dry machining to 369.8oK (16% improvement) during machining with used-engine oil and 362.6oK (18% improvement) during machining with soluble oil. The surface roughness produced was generally higher while machining with used-engine oil with an average improvement of 39% in surface integrity. However, when soluble oil was used as cutting fluid, average improvement in surface integrity increased to 70%. Hence, used-engine oil offered impressive lubricating and cooling properties and could replace soluble oil as a cutting fluid during machining.Keywords—Cutting Fluid, Cutting Speed, Machining, Surface Roughness, Tool Wear


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Amrita Maddamasetty ◽  
Kamesh Bodduru ◽  
Siva Bevara ◽  
Rukmini Srikant Revuru ◽  
Sanjay Kumar

Purpose Inconel 718 is difficult to machine due to its high toughness and study hardenability. Though the use of cutting fluids alleviates the problem, it is not sustainable. So, supply of a small quantity of specialized coolant to the machining zone or use of a solid lubricant is a possible solution. The purpose of the present work is to improve machinability of Inconel718 using graphene nanoplatelets. Design/methodology/approach In the present study, graphene is used in the machining of Inconel 718 alloy. Graphene is applied in the following two forms: as a solid lubricant and as an inclusion in cutting fluid. Graphene-based self-lubricating tool and graphene added nanofluids are prepared and applied to turning of Inconel 718 at varying cutting velocities. Performances are compared by measuring cutting forces, cutting temperature, tool wear and surface roughness. Findings Graphene, in both forms, showed superior performance compared to dry machining. In total, 0.3 Wt.% graphene added nanofluids showed the lowest cutting tool temperature and flank wear with 44.95% and 83.37% decrease, respectively, compared to dry machining and lowest surface roughness, 0.424 times compared to dry machining at 87 m/min. Originality/value Graphene could improve the machinability of Inconel 718 when used in tools as a solid lubricant and also when used as a dispersant in cutting fluid. Graphene used as a dispersant in cutting fluid is found to be more effective.


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