CFRP composite drilling through electrical discharge machining using aluminum as fixture plate

Author(s):  
Suvranshu Pattanayak ◽  
Ananda Kumar Sahoo ◽  
Susanta Kumar Sahoo

Recent developments in manufacturing require holes on composite materials, especially on the carbon fiber reinforced polymer (CFRP) with smooth hole periphery, low delamination, burr formation, taper, better circularity, and a high processing speed. Its non-conductive surface (epoxy layering) limits its machining through electrical discharge machining (EDM). To overcome this limitation, an aluminum fixture has been designed to guide the copper electrode of EDM for producing holes on a CFRP sheet of 1 mm thickness at low machining complexity, cost, time, delamination, burr in hole periphery and without affecting the material’s surface quality and performance. Even components with high geometrical complexity can also be drilled through this approach. Here, a multi-quality analysis called grey relational analysis is developed for examining the hole quality attributes, considering peak current, pulse on and off time, and flushing pressure as input parameters. This approach points out the optimum factor level setting and critical parameters (pulse-on time and peak current) that regulate the hole attributes (entrance and exit diameter, circularity, taper, material removal, and tool wear rate). An artificial neural network model has been designed and trained through experimental data sets. This model can also be adopted during the determination of hole quality attributes when the parameter settings are beyond a defined boundary, as the regression analysis value is very close to 1, and model performance is 4.99e-10. Peak current = 4 A, pulse-on time = 25 µs, pulse-off time=25 µs, and flushing pressure = 0.6 MPa were the optimum drilling parameters. In the initial hole, average burr length is 391.75 μm, and delamination of 539.3 μm is noticed. But burr formation is very negligible with delamination of 350.7 μm being observed with uniform circularity (0.979), low taper angle (−0.81354°), and TWR (0.000069 g/min) under optimum drilling conditions through this drilling approach.

2012 ◽  
Vol 488-489 ◽  
pp. 871-875
Author(s):  
V. Anandakrishnan ◽  
V. Senthilkumar

Copper based metal matrix composite reinforced with Boron Carbide is a newly developed Electrical Discharge Machining (EDM) electrode showing better performance than the conventional copper based electrode. Right selection of machining parameters such as current, pulse on time and pulse off time is one of the most important aspects in EDM. In this paper an attempt has been made to develop mathematical models for relating the Material Removal Rate (MRR), Tool Removal Rate (TRR) and Surface roughness (Ra) to machining parameters (current, pulse-on time and pulse-off time). Furthermore, a study was carried out to analyze thSubscript texte effects of machining parameters on various performance parameters such as, MRR, TRR and Ra. The results of Analysis of Variance (ANOVA) indicate that the proposed mathematical models, can adequately describe the performance within the limits of the factors being studied. Response surface modeling is used to develop surface and contour graphs to analyze the effects of EDM input parameters on outer parameters.


Author(s):  
Debal Pramanik ◽  
Dipankar Bose

An important electro-thermal process known as wire electrical discharge machining (WEDM) is applied for machining of conductive materials to generate most precisely. All cutting inaccuracies of WEDM arise out of the major cause of wire bending. At the time of cutting a sharp corner or cut profile, bending of the wire leads to a geometrical error on the workpiece. Though this type of error may be of a few hundred microns, it is not suitable for micro applications. In this research study, an experimental investigation based on response surface methodology (RSM) has been done on wire EDM of Aluminium 6061 t6 alloy. This chapter studies the outcome of input process variables (i.e., wire feed rate, pulse on time, pulse off time, and gap voltage) on machining output responses (i.e., corner inaccuracy) extensively. Experimental validation of the proposed model shows that corner inaccuracy value may be reduced by modification of input parameters.


2015 ◽  
Vol 14 (03) ◽  
pp. 189-202 ◽  
Author(s):  
V. Vikram Reddy ◽  
P. Madar Valli ◽  
A. Kumar ◽  
Ch. Sridhar Reddy

In the present work, an investigation has been made into the electrical discharge machining process during machining of precipitation hardening stainless steel PH17-4. Taguchi method is used to formulate the experimental layout, to analyze the effect of each process parameter on machining characteristics and to predict the optimal choice for each electrical discharge machining process parameters namely, peak current, pulse on time and pulse off time that give up optimal process performance characteristics such as material removal rate, surface roughness, tool wear rate and surface hardness. To identify the significance of parameters on measured response, the analysis of variance has been done. It is found that parameters peak current and pulse on time have the significant affect on material removal rate, surface roughness, tool wear rate and surface hardness. However, parameter pulse off time has significant affect on material removal rate. Confirmation tests are conducted at their respective optimum parametric settings to verify the predicted optimal values of performance characteristics.


2015 ◽  
Vol 766-767 ◽  
pp. 902-907
Author(s):  
Bibin K. Tharian ◽  
B. Kuriachen ◽  
Josephkunju Paul ◽  
Paul V. Elson

Wire electrical discharge machining is one of the important non-traditional machining processes for machining difficult to machine materials. It involves the removal of material by the discrete electric discharges produced between the inter electrode gap of continuously moving wire electrode and the work piece. The ability to produce intricate profiles on materials irrespective of the mechanical properties made this process to be widely used in industries. The present study investigates the relationship of various process parameters in WEDM of AISI 202 stainless steel with brass electrode.The experiments were planned according to Taguchi’s L18 orthogonal array and experimental models were developed. The important process parameters identified for the present study were pulse on time, peak current, pulse off time, wire feed, wire tension, dielectric flushing pressure, servo feed and gap voltage. The surface roughness of the machined surface was measured as the process performance measure. Analysis of variance test has also been carried out to check the adequacy of the developed models and to identify the level of significance of each process parameters. In addition to the developed models, ABC optimization has been performed to identify the optimum parameter combination for minimum surface roughness and the obtained optimal process parameters are peak current 11 A, pulse on time 100 μs, pulse off time 49 μs, wire feed 4 m/min, wire tension 10 N, flushing pressure 12 kg/cm2, servo feed 2100 mm/min and set gap voltage 30 V. Finally the results were verified with the experimental results and found that they are in good agreement.


2018 ◽  
Vol 14 (4) ◽  
pp. 115-124 ◽  
Author(s):  
Shukry H. Aghdeab ◽  
Nareen Hafidh Obaeed ◽  
Marwa Qasim Ibraheem

Electrical Discharge Machining (EDM) is a non-traditional cutting technique for metals removing which is relied upon the basic fact that negligible tool force is produced during the machining process. Also, electrical discharge machining is used in manufacturing very hard materials that are electrically conductive. Regarding the electrical discharge machining procedure, the most significant factor of the cutting parameter is the surface roughness (Ra). Conventional try and error method is time consuming as well as high cost. The purpose of the present research is to develop a mathematical model using response graph modeling (RGM). The impact of various parameters such as (current, pulsation on time and pulsation off time) are studied on the surface roughness in the present research. 27 samples were run by using CNC-EDM machine which used for cutting steel 304 with dielectric solution of gas oil by supplied DC current values (10, 20, and 30A). Voltage of (140V) uses to cut 1.7mm thickness of the steel and use the copper electrode. The result from this work is useful to be implemented in industry to reduce the time and cost of Ra prediction. It is observed from response table and response graph that the applied current and pulse on time have the most influence parameters of surface roughness while pulse off time has less influence parameter on it. The supreme and least surface roughness, which is achieved from all the 27 experiments is (4.02 and 2.12µm), respectively. The qualitative assessment reveals that the surface roughness increases as the applied current and pulse on time increases


2014 ◽  
Vol 68 (1) ◽  
Author(s):  
Md. Ashikur Rahman Khan ◽  
M. M. Rahman

Electrical discharge machining (EDM) produces complex shapes and permits high-precision machining of any hard or difficult-to-cut materials. The performance characteristics such as surface roughness and microstructure of the machined face are influenced by numerous parameters. The selection of parameters becomes complicated. Thus, the surface roughness (Ra) and microstructure of the machined surface in EDM on Grade 6 titanium alloy are studied is this study. The experimental work is performed using copper as electrode material. The polarity of the electrode is maintained as negative. The process parameters taken into account in this study are peak current (Ip), pulse-on time (Ton), pulse-off time (Toff), and servo-voltage (Sv). A smooth surface finish is found at low pulse current, small on-time and high off-time. The servo-voltage affects the roughness diversely however, a finish surface is found at 80 V Sv. Craters, cracks and globules of debris are appeared in the microstructure of the machined part. The size and degree of craters as well as cracks increase with increasing in energy level. Low discharge energy yields an even surface. This approach helps in selecting proper process parameters resulting in economic EDM machining. 


2020 ◽  
Vol 853 ◽  
pp. 13-17
Author(s):  
Le Hong Ky ◽  
Thi Hong Tran ◽  
Nguyen Van Cuong ◽  
Tran Thanh Hoang ◽  
Do Thi Tam ◽  
...  

This paper introduces an experimental study on the influence of electrical discharge machining (EDM) cylindrical shaped parts made of 90CrSi tool steel. In this work, some experiments were designed and analysed based on Taguchi method. Also, four input parameters including the pulse on time, the pulse off time, the current, and the server voltage were investigated. The influence of these parameters on the surface roughness were estimated by analysing variance. In addition, the optimum input parameters were found for getting the minimum surface roughness.


2020 ◽  
Vol 62 (5) ◽  
pp. 481-491
Author(s):  
Engin Nas

Abstract This study investigated the electrical discharge machining (EDM) performance of Ramor 500 Armor steel, a material used in the defense industry for armor production. In addition, the surface quality and amount of material wear of the treated surfaces were determined using different electrical discharge processing parameters for a copper electrode including pulse on-time (99, 150, 225, 300, 351 μs), pulse off-time (10, 15, 23, 30, 35 μs), and discharge current (3, 4, 6, 8, 9 A), at a constant pressure of 1 mm depth of cut. As a result of the experiments, the values related to the material removal rate (MRR) and the surface roughness (Ra) were obtained and the findings analyzed via response surface methodology (RSM). The increase in amperage and pulse on time resulted in an increase in Ra and MRR values. The minimum and maximum Ra and MRR values emerged at currents of 3 and 9 A, respectively. In the experiments performed applying currents of between 3 and 9 A, the white layer widths were measured as 0.0474 mm and 0.0915 mm, respectively. The statistical test results showed that the most effective processing parameters for the MRR were the discharge current amperage (49.01 %) and the pulse off-time (16.51 %), whereas the most effective parameter for the Ra value was the discharge current amperage (79.07 %).


2019 ◽  
Vol 69 (1) ◽  
pp. 17-38 ◽  
Author(s):  
De Dwaipayan ◽  
Nandi Titas ◽  
Bandyopadhyay Asish

AbstractIn 21st century, it has been observed that Wire Cut Electrical Discharge Machining (WEDM) has evolved as one of the most important non-traditional machining process. The popularity and its success lies because of its uniqueness towards producing different components which are very difficult to machine like titanium, tungsten carbide, Inconel materials etc and provides a platform in producing intricate complex shape which in many cases become impossible to machine by traditional machining methods. Pure sintered titanium bears very high specific strength, abrasion and corrosion resistances and thus machining this type of materials by conventional techniques becomes very difficult though this material finds immense applications in bio-plant and aerospace components. In the present work, WEDM on pure sintered titanium is studied. The different input parameters of WEDM like, pulse on time, pulse off time, wire tension and wire feed have been varied to investigate the output response like MRR, Surface Roughness (Ra), Kerf Width and Over Cut. A response surface methodology (4 factors 3 level) design of experiment (DOE) has been applied in this context to examine the machining ability of pure sintered titanium and results are found to be satisfactory and verified by confirmatory test. The machining parameters like pulse on time, pulse off time, wire tension and wire feed shows immense effect on the output responses and present study provide an optimal conditions of these input parameters to get the best output responses through RSM


2015 ◽  
Vol 787 ◽  
pp. 366-370 ◽  
Author(s):  
Vaibhav Gaikwad ◽  
Vijaykumar S. Jatti ◽  
T.P. Singh

NiTi alloys possess superior material properties such as high specific strength, high corrosion resistance, high wear resistance and high anti-fatigue property. Due to these properties it is difficult to machine these alloys using conventional machining process. Nowadays non-conventional machining processes are widely used for machining such adavanced materials. Electrical Discharge machining (EDM) is one such non-conventional process, which can machine electrically conductive materials of any hardness values. Present study aims at drilling mesoscale 3 mm square holes on NiTi alloy by varying the electrical parameters namely, gap current, pulse on time and pulse off time. Additional, the present work includes finding out the effect of cryogenic treatment of NiTi work material on electrical discharge machining performance measures namely material removal rate (MRR) and tool wear rate (TWR). Based on experiments conducted, it can be concluded that with increase in current both material removal rate and tool wear rate increases. It is also noted that cryo-treatment of workpiece material improves MRR with respect to gap current. Similarly there is an increase in MRR with respect to pulse on time and pulse off time for cryo-treated workpiece material. There is a slight improvement of TWR with respect to gap current, pulse on time and pulse off time for cryo-treated workpiece material.


Sign in / Sign up

Export Citation Format

Share Document