Crystallography, compositions, and properties of white layer by wire electrical discharge machining of nitinol shape memory alloy

This study deals with the development of a new method of directly measuring the movement of an electrode during normal electrical discharge machining (EDM) and the movement of an electrode during EDM by means of an automatic discharge gap controller (ADGC) devised by our research group. The ADGC, which mainly consists of a bidirectional actuator using a shape memory alloy (SMA) and an electrode and power supply for EDM, can sustain stable EDMby autonomously and automatically controlling the position of the electrode to keep the discharge gap appropriate. However, the movement of the electrode being controlled by the ADGC cannot be directly measured due to itsminute, high-speed, vibration-like movements inside the working fluid during EDM. This means that there is no way to prove that the ADGC actually controls the position of the electrode so as to maintain a suitable discharge gap for continuing stable EDM. This also means that there is no way to evaluate the movement of the electrode quantitatively and to design or optimize the structure of an ADGC so as to give the ADGC the desired or best performance. Therefore, a method to directlymeasure the electrodemovement by an ADGC is devised in this study. The results obtained in the measurement experiments using this method of measurement prove that the ADGC actually moves its electrode to achieve stable EDM, and they allow the movement of the electrode to be evaluated quantitatively.

Download Full-text

Optimasi Multirespon Proses Wire Electrical Discharge Machining untuk Pengerjaan Komponen Punch and Dies Bracket Konstruksi Kapal Alumunium

Jurnal Energi Dan Manufaktur ◽

10.24843/jem.2019.v12.i02.p11 ◽

2019 ◽

Vol 12 (2) ◽

pp. 107

Author(s):

Fipka Bisono ◽

Dhika Aditya P.

Keyword(s):

Surface Roughness ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

White Layer ◽

Performance Characteristics ◽

Machining Process ◽

Wire Electrical Discharge Machining ◽

Process Variables ◽

Relational Analysis ◽

Wedm Process

Wire electrical discharge machining(WEDM) banyak digunakan untuk proses pembuatan punch and dies. Dimana material yang digunakan memiliki tingkat kekerasan yang sangat tinggi. Parameter pemesinan yang kurang tepat dapat menyebabkan hasil pemotongan yang tidak optimal. Penelitian ini dilakukan untuk mengoptimalkan beberapa karakteristik hasil proses pemesinan secara serentak dengan cara mevariasikan variabel-variabel proses pemesinan WEDM. Karakteristik hasil proses yang diteliti antara lain adalah lebar pemotongan, kekasaran permukaan, dan tebal lapisan white layer. Proses pemesinan dilakukan pada material tool steel SKD 11. Arc on time, on time, open voltage dan servo voltage merupakan variabel-variabel proses yang akan divariasikan. Rancangan percobaan dilakukan menggunakan metode Taguchi dengan matriks ortogonal L18(21x33) dengan dua kali replikasi. Sedangkan langkah yang digunakan untuk mengoptimasi karakteristik hasil proses pemesinan yang diteliti secara serentak adalah menggunakan metode grey relational analysis (GRA). Lebar pemotongan, kekasaran permukaan dan tebal lapisan white layer memiliki performance characteristics “smaller-is-better.” Hasil dari penelitian menunjukkan nilai variabel-variabel proses pemesinan yang menghasilkan kualitas karakteristik yang paling optimum adalah sebagai berikut: arc on time (1A), on time (4?s), open voltage (70V), dan servo voltage (40V). Dengan persentase kontribusi variabel proses dari yang terbesar berturut-turut adalah on time (65,09%), open voltage (11,35%), arc on time (7,71%), dan servo voltage (5,61%). Wire electrical discharge machining (WEDM) process is commonly used to make punch and dies. WEDM services are typically used to cut hard metals. Inappropriate machining parameters can cause suboptimal cutting results. This research was conducted to optimize several characteristics of the machining process simultaneously by varying WEDM machining process variables. Performance characteristics of the WEDM process include the kerf, surface roughness and thickness of the white layer. The machining process is carried out on SKD 11 tool steel material. Arc on time, on time, open voltage and servo voltage are process variables that will be varied. The experimental matrix design was carried out using the Taguchi method L18 (21x33) orthogonal array with two replications. Then to optimize the performance characteristics of the machining process simultaneously is using the Gray Relational Analysis (GRA) method. Performance characteristics of kerf, surface roughness, and thickness of the white layer is "smaller-is-better". The results of the experiment indicate the value of the machining process variables that produce the most optimum quality performance characteristics are as follows: arc on time (1A), on time (4?s), open voltage (70V), and servo voltage (40V). And the percentage of contribution of the process variables from the largest to smallest are as follows: on time (65,09%), open voltage (11,35%), arc on time (7,71%), and servo voltage (5,61%).

Download Full-text

Electrical discharge machining for the formation of bulk-shape memory alloy actuators

Micro Electro-Fabrication ◽

10.1016/b978-0-12-820049-0.00007-4 ◽

2021 ◽

pp. 195-217

Author(s):

Md. Nazibul Hasan ◽

Mohamed Sultan Mohamed Ali

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Electrical Discharge ◽

Electrical Discharge Machining

Download Full-text

Electrical discharge machining of a NiAlFe ternary shape memory alloy

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2007.10.012 ◽

2008 ◽

Vol 464 (1-2) ◽

pp. 446-451 ◽

Cited By ~ 21

Author(s):

S.L. Chen ◽

S.F. Hsieh ◽

H.C. Lin ◽

M.H. Lin ◽

J.S. Huang

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Electrical Discharge ◽

Electrical Discharge Machining

Download Full-text

Effects of abrasive types on the surface integrity of abrasive-flow-machined surfaces

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405416662080 ◽

2016 ◽

Vol 232 (6) ◽

pp. 1044-1053 ◽

Cited By ~ 10

Author(s):

Kursad Gov ◽

Omer Eyercioglu

Keyword(s):

Surface Roughness ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

White Layer ◽

Machining Process ◽

Wire Electrical Discharge Machining ◽

Abrasive Flow Machining ◽

The Media ◽

Surface Improvement

In this article, the effect of abrasive types on the abrasive flow machining process was investigated. Four groups of abrasive media were prepared with different types of abrasives: SiC, AL2O3, B4C and Garnet. An experimental study was performed on DIN 1.2379 tool steel. The specimens were cut using wire electrical discharge machining and finished with the abrasive flow machining process. The results show that the white layer that formed during wire electrical discharge machining was successfully removed by abrasive flow machining in a few cycles. Although the surface roughness improves with similar trends for all media groups, the results show that the media prepared with B4C and SiC have more surface improvement than the Al2O3 and Garnet ones. The resulting average surface roughness (Ra) values are comparable to the surface quality of those obtained from lapping and super-finishing. The material removal is directly related to the hardness of the abrasive.

Download Full-text