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The ichnography of 316L stainless steel cardiovascular stent. (a) X–Z ichnography and (b) Y–Z ichnography.
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A metallic cardiovascular stent cutting system based on fiber laser was designed in this study. In order to achieve the cutting of stent, the main modules and the key technologies were analyzed and achieved. Then with the cutting system, the kerf width size was studied for different cutting parameters including laser output power, pulse length, rep...
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... the material characteristics and the mechanical performance [8]. Finally, this data are fed to the laser processing system and then the cutting of the desired pattern can be performed with the programming process. In order to show the characteristics of the fiber laser cutting system, we designed a simple kind of cardiovascular stent, shown in Fig. 2 CAD configuration. The 316L stainless steel tube (thickness 110 mm, diameter 2 mm) was used in the cutting experiment. Fig. 3 shows the kerf width as a function of the cutting speed for different laser output powers. The repeat frequency was 1500 Hz, pulse lengths 0.15 ms and assisting oxygen gas pressure 0.3 MPa. The kerf width size ...
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The present work reports the parameters on laser cutting stainless steel including workpiece thickness, cutting speed, defocus length and assisting gas pressure. The cutting kerf width, dross attachment and cut edge squareness deviation are examined to provide information on cutting quality. The results show that with the increasing thickness, the...
Laser cutting of thick steel plates and simulated steel components using a 30 kW fiber laser was studied for application to nuclear decommissioning. Successful cutting of carbon steel and stainless steel plates up to 300 mm in thickness was demonstrated, as was that of thick steel components such as simulated reactor vessel walls, a large pipe, and...
Citations
... For instance, steel tubes can be manufactured through processes such as extrusion, drawing, and welding. However, specific types of tubular structures, such as tubular grafts, are typically fabricated using laser subtractive manufacturing [6][7][8]. The movement of the laser point allows the creation of various patterns on polymeric tubes. ...
3D printing techniques offer an effective method in fabricating complex radially multi-material structures. However, it is challenging for complex and delicate radially multi-material model geometries without supporting structures, such as tissue vessels and tubular graft, among others. In this work, we tackle these challenges by developing a polar digital light processing technique which uses a rod as the printing platform. The 3D model fabrication is accomplished through line projection. The rotation and translation of the rod are synchronized to project and illuminate the photosensitive material volume. By controlling the distance between the rod and the printing window, we achieved the printing of tubular structures with a minimum wall thickness as thin as 50 micrometers. By controlling the width of fine slits at the printing window, we achieved the printing of structures with a minimum feature size of 10 micrometers. Our process accomplished the fabrication of thin-walled tubular graft structure with a thickness of only 100 micrometers and lengths of several centimeters within a timeframe of just 100 s. Additionally, it enables the printing of axial multi-material structures, thereby achieving adjustable mechanical strength. This method is conducive to rapid customization of tubular grafts and the manufacturing of tubular components in fields such as dentistry, aerospace, and more.
... Finally, the vascular stent is cut off from the tube [24]. Different types of laser techniques can be used in the manufacture of stents, such as CO 2 laser [25], Nd:YAG laser [26], fiber laser [27], excimer laser [28] and ultrashort pulse laser [29] and so on. The stent fabricated by laser technology has the advantages of high precision, which is widely concerned. ...
Cardiovascular disease has become the leading cause of death. A vascular stent is an effective means for the treatment of cardiovascular diseases. In recent years, biodegradable polymeric vascular stents have been widely investigated by researchers because of its degradability and clinical application potential for cardiovascular disease treatment. Compared to non-biodegradable stents, these stents are designed to degrade after vascular healing, leaving regenerated healthy arteries. This article reviews and summarizes the recent advanced methods for fabricating biodegradable polymeric stents, including injection molding, weaving, 3D printing, and laser cutting. Besides, the functional modification of biodegradable polymeric stents is also introduced, including visualization, anti-thrombus, endothelialization, and anti-inflammation. In the end, the challenges and future perspectives of biodegradable polymeric stents were discussed.
... Also, laser machining is very effective in producing micro indents, biomedical implants, etc., without causing considerable damage to the properties of the material. The laser micromachining process is primarily used to produce medical devices such as vascular stents [34,35]. Laser machining is a complex process involving various variables such as power, stand-off distance, frequency, pressure, pulse width, pulse overlap, speed, etc., and the control of these parameters is necessary to produce a properly machined surface with good surface finish and better quality. ...
The term 'shape memory alloys' (SMAs) refer to a group of metallic materials that have the ability to return to a previously defined shape when subjected to the appropriate thermal or loading cycles. They are now being employed in different real-life applications. Cu-Al-Fe is a High Temperature Shape Memory Alloy (HTSMA) and could replace Ni-Ti SMAs. Conventional machining technologies are not efficient enough in machining SMAs, and thus the properties of the SMAs are affected. One of the most successful technologies for processing these alloys is Laser Beam Machining (LBM). This work shows an investigation of the effect of process variables in laser machining on SMA. Differential scanning calorimetry, X-Ray Diffraction, Optical Microscopy, Scanning Electron Microscopy, and Hardness tests were used to analyze the laser-machined material. It has been found that power was the highest influencing variable which affects Material Removal Rate (MRR) and Surface Roughness (Ra), and the second most influencing parameter was cutting speed. DSC thermograms confirm that the Shape Memory Effect (SME) and the transition temperatures of the SMA have not been much affected after machining. The hardness of the machined surface slightly increased after machining, owing to the formation of a re-solidified layer.
... Given these characteristics, the laser processing of NiTi SMAs appears more complex than that of other metallic alloys, because the feasibility of the process must be fixed not only by considering typical technological constraints (quality Fig. 9 e Schematic of the laser cutting system used to fabricate a stent from a tube [36]. and productivity), but also by endeavouring to limit the changes in functional performance. ...
Since several years the need for realizing small and smart devices composed of functional materials is constantly increasing. Among this advanced materials, shape memory alloys (SMAs) are some of the most important functional materials in several applications, including in the biomedical and aerospace fields. Nowadays, laser cutting is probably the most widespread cutting technology for realising SMA mini- and micro-devices for several applications. The present manuscript reviews the scientific literature on the performance of laser-cut elements, in NiTi SMA, under different points of view. The literature was systematically analysed, according with a technological, metallurgical, functional and device/prototypal approaches. It can be highlighted that a relevant correlation between design, process condition and material performances can promote the realization of advanced smart devices made in NiTi SMA.
... The data is then analyzed with FEA in order to evaluate its efficiency. In the next step, these data are imported to the laser processing system and the cutting process of the stent is performed [206]. ...
The present review gives an overview of the composition and fabrication technologies of metallic cardiovascular stents and their effects on the stent characteristics and function. The fabrication process has a significant effect on geometry and the design characteristics of the stent and imparts different microstructure, corrosion behavior, and mechanical properties to the fabricated stent. Therefore, the operational and functional efficiency of stents in the body is dependent on the manufacturing process. Several stents have been developed and used for the treatment of cardiovascular diseases since their introduction as atherosclerosis remedy, including bare-metal stents (BMS), drug‐eluting stents (DES), and bio-resorbable stents (BRS). Accordingly, various methods have been evaluated to fabricate stents in accordance with desired performance. Although several reviews have been published on the function and clinical success of various stent materials, there is a lack of information about the impact of various fabrication methods of metallic stents on their final features and functionality. The current work investigates a variety of conventional and modern methods that are used for the fabrication of metallic cardiovascular stents.
... It suggests that fiber laser has great potential in PCL stent machining. Meng et al. [55] designed a fiber laser cutting system for metallic stent fabrication, and the experimental results indicated that the kerf width plays an important role in the machining quality of 316 L stainless-steel stents. Muhammad et al. [56] fabricated nitinol and platinum-iridium alloy vascular stent by picosecond laser micromachining. ...
... Laser cutting [44][45][46][47][48][49][50][51][52][53][54][55][56] Good quality High processing accuracy Heat-affected zone 3D printing [57][58][59][60][61][62][63][64] Personalized customization High material utilization Poor accuracy µEDM ...
Percutaneous coronary intervention (PCI) with stent implantation is one of the most effective treatments for cardiovascular diseases (CVDs). However, there are still many complications after stent implantation. As a medical device with a complex structure and small size, the manufacture and post-processing technology greatly impact the mechanical and medical performances of stents. In this paper, the development history, material, manufacturing method, and post-processing technology of vascular stents are introduced. In particular, this paper focuses on the existing manufacturing technology and post-processing technology of vascular stents and the impact of these technologies on stent performance is described and discussed. Moreover, the future development of vascular stent manufacturing technology will be prospected and proposed.
... Addressing this Stents are used as a support for blood vessels, canals or ducts, or to aid and heal the obstruction of an artery, they are commonly used on the percutaneous transluminal coronary angioplasty (PTCA) to reduce the blockage of coronary arteries [1] which has been the primary leading cause of death globally for the last years [2]. For stents, several materials have been studied including stainless steel [3][4][5], CoCr alloys [6] and nitinol sheets [10]. Nitinol (NiTi alloy) self-expanding stents have been widely used for angioplasty procedures and have been broadly researched for its shape-memory effect [7][8][9]. ...
... Stents are used as a support for blood vessels, canals or ducts, or to aid and heal the obstruction of an artery, they are commonly used on the percutaneous transluminal coronary angioplasty (PTCA) to reduce the blockage of coronary arteries [1] which has been the primary leading cause of death globally for the last years [2]. For stents, several materials have been studied including stainless steel [3][4][5], CoCr alloys [6] and nitinol sheets [10]. Nitinol (NiTi alloy) self-expanding stents have been widely used for angioplasty procedures and have been broadly researched for its shape-memory effect [7][8][9]. ...
Medical devices require features at the micro-scale which represent a challenge for the manufacturing process. Fiber laser cutting is capable to generate micro geometries with high accuracy and low surface roughness. Nitinol is a self-expanding material with the unique capacity of self-deployment and performance in the medical industry. In this work, we presented the influence of laser cutting parameters (i.e., feed rate, laser pulse frequency, pulse width and laser power) on surface roughness of Nitinol manufactured by fiber laser cutting. Our results indicate that the association of laser parameters in spot overlapping, and pulse energy contributes to reduce variables and to analyze the surface topography making laser power and feed rate of great significance in the manufacturing process of nitinol. Additionally, a combination of a laser pulse frequency of 600 Hz and a feed rate of 500 mm/min (Of = 78.3%) resulted with the lowest values of surface roughness (~0.96 µm), while increasing the feed rate to 750 mm/min (Of = 67.4%) resulted with the highest values of surface roughness (~2.1 µm).
... In addition, the telecommunications industry itself is potentially a natural area of application for the results of research in the field of fiber optics and fiber laser systems. Further, fiber laser systems have also proved to be very effective tools in the field of material processing: from industrial processing (welding, cutting, hardening, cleaning, and marking) [10] to precision micromachining of various objects [11] and biomedical manipulations of organic tissues [12]. The emergence and increasing implementation of efficient high-precision metrology systems based on fiber laser systems, e.g., in the field of time-and-frequency metrology [13] should also be noted. ...
... Liu et al. (2005) [5] compared traditional laser to fiber laser cutting system and found out that laser power, pulse length and pulse frequency can be tuned to meet the requirements for various kinds of stents cutting and micro-machining. Meng et al. (2009) [6] showed that fiber laser cutting a 316L stainless steel cardiovascular stent had better surface quality than cutting with YAG laser. It can be seen that the heat affected zone and the roughness are better by fiber laser cutting. ...
... Liu et al. (2005) [5] compared traditional laser to fiber laser cutting system and found out that laser power, pulse length and pulse frequency can be tuned to meet the requirements for various kinds of stents cutting and micro-machining. Meng et al. (2009) [6] showed that fiber laser cutting a 316L stainless steel cardiovascular stent had better surface quality than cutting with YAG laser. It can be seen that the heat affected zone and the roughness are better by fiber laser cutting. ...
The typical manufacturing process of tubular metallic cardiovascular stents includes laser cutting, sand blasting, acid pickling, electropolishing, surface passivation, and cleaning. The most commonly used material for cardiovascular stents is stainless steel, such as SUS 304 and SUS 316. After the laser cutting process, substantial improvement of the stent surface morphology is required to obtain acceptable surface roughness, edge roundness, and reduction of surface defects. This study focuses on a novel post-treatment method of fluid abrasive machining to replace the conventional sand blasting and acid pickling processes, resulting in the surface smoothness and edge roundness that are suitable for cardiovascular stent fabrication. The dross deposition and striations retained after laser cutting can be significantly removed with fluid abrasive machining. Both DC current and pulse current electropolishing techniques were performed to attain the final surface and structural quality after the fluid abrasive machining process. The experimental results show that an extremely fine surface roughness and a satisfactory edge roundness can be achieved for stents through both DC current and pulse current electropolishing. The pulse electropolishing process is more effective than the DC current electropolishing process to achieve edge roundness with less weight removal.
... As the precise medical device, the manufacturing methods of vascular stents mainly include braided method (Figure 7a) [75][76][77][78], laser cutting method (Figure 7b) [79][80][81][82], electrospinning technology (Figure 7c) [83][84][85][86] and additive manufacturing technology (Figure 7d) [87][88][89][90][91]. The braided method is to first wind the wire on the carrier. ...
Percutaneous Coronary Intervention (PCI) is currently the most conventional and effective method for clinically treating cardiovascular diseases such as atherosclerosis. Stent implantation, as one of the ways of PCI in the treatment of coronary artery diseases, has become a hot spot in scientific research with more and more patients suffering from cardiovascular diseases. However, vascular stent implanted into vessels of patients often causes complications such as In-Stent Restenosis (ISR). The vascular stent is one of the sophisticated medical devices, a reasonable structure of stent can effectively reduce the complications. In this paper, we introduce the evolution, performance evaluation standards, delivery and deployment, and manufacturing methods of vascular stents. Based on a large number of literature pieces, this paper focuses on designing structures of vascular stents in terms of “bridge (or link)” type, representative volume unit (RVE)/representative unit cell (RUC), and patient-specific stent. Finally, this paper gives an outlook on the future development of designing vascular stents.
