Study on the variation of recast layer in laser trepan drilling by millisecond Nd:YAG laser

2020 ◽  
Vol 564 (1) ◽  
pp. 128-145
Author(s):  
Wenqiang Duan ◽  
Zhengjie Fan ◽  
Yifei Zhang
2021 ◽  
pp. 251659842110154
Author(s):  
B. Muralidharan ◽  
K. Prabu ◽  
G. Rajamurugan

Nickel–Titanium (Ni-Ti) shape memory alloy, commonly called nitinol alloys, finds its primary application in the production of biomedical implants, mainly because of itsrare properties such asshape memory, superelasticity and superior biocompatibility. Laser cutting is anon-traditional machining process for the production ofparts with close tolerances andcomplex geometry. Electrical discharge machining (EDM) of nitinol is associated with more heat-affected zone (HAZ) and recast layer thickness. This article aims to study nitinol’s machining characteristics by alaser source with good beam quality to have a less HAZ, recast layer and striations. Experiments were designed and carried out using central composite designs (CCD) by a pulsed Nd:YAG laser. Analysis based on the different parameters chosen was conducted to determine the parameters; effects, including laser power, frequency and cutting speed concerning the surface roughness. From the results, it is observed that the presence of HAZ is measured up to1. 48 mm from the machined surface. The topography analysis reveals that the striation is identified at high speeds, with less pulse overlapping by columnar micro channels, which can be reduced at high pulse frequency.


2020 ◽  
Vol 37 (3) ◽  
pp. 804 ◽  
Author(s):  
Wenqiang Duan ◽  
Xuesong Mei ◽  
Zhengjie Fan ◽  
Jingmeng Chen ◽  
Yifei Zhang

VASA ◽  
2011 ◽  
Vol 40 (3) ◽  
pp. 235-240 ◽  
Author(s):  
Krnic ◽  
Sucic

Background: The aim of this study is to report our results in main stem vein closure using the bipolar radiofrequency induced thermotherapy (RFITT) system and the 1064nm Nd:Yag laser. Patients and methods: 44 incompetent main stem veins (37 great saphenous veins, one lesser saphenous vein, and 6 anterior accessory saphenous veins) in 29 patients were treated using RFITT. 53 incompetent main stem veins (45 great saphenous veins, 4 lesser saphenous veins, and 4 anterior accessory saphenous veins) in 43 patients were treated endovenously with 1064 nm Nd:Yag laser. All patients underwent postoperative duplex scanning within a month after procedure, as well as a short interview regarding postoperative discomfort. Results: In main stem veins treated with RFITT, the success rate within the first month was 86,4 % (38 out of 44 veins). Complete failure rate was 13,6 % (6 out of 44 veins). In 53 main stem veins treated by 1064 nm Nd:Yag laser, the success rate was 100 %, consisting of 98,1 % complete success (52/53 veins), and 1,9 % partial success (1/53 veins). None of the patients treated with RFITT experienced postoperative adverse effects, whereas 13/43 (30,2 %) patients treated with laser had to use oral analgesics after the treatment, and 21/43 (48,8 %) patients reported transient skin changes, such as bruising or skin redness. Conclusions: RFITT system was fairly efficient in the short term for closure of main trunk veins, whereas longer term results are still scarce. Postoperative side effects of RFITT were minimal. 1064nm Nd:Yag laser, according to short term results, proved to be very effective for main stem vein closure. Postoperative side effects related to 1064 nm Nd:Yag endovenous laser treatment proved to be minor, transient, and acceptable.


2020 ◽  
Vol 10 (03) ◽  
pp. 243-254
Author(s):  
Albrecht Lommatzsch

ZusammenfassungDas Management von symptomatischen Glaskörpertrübungen stellt sich in der täglichen Praxis oft als kompliziert dar. Die Nd:YAG-Laser-Vitreolyse rückt als weitere therapeutische Option immer mehr in den Fokus. Vergleichende randomisierte Studien zur Vitrektomie, Nd:YAG-Laser-Vitreolyse und einer abwartenden Vorgehensweise zum Spontanverlauf gibt es leider nicht. Dieser Beitrag versucht, zu dieser Problematik einen Überblick zu geben.


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