In recent years, additive manufacturing, also known as three-dimensional (3D) printing, has emerged as an environmentally friendly green manufacturing technology which brings great benefits, such as energy saving, less material consumption, and efficient production. These advantages are attributed to the successive material deposition at designated target areas by delivering the energy on it. In this regard, lasers are the most effective energy source in additive manufacturing since the laser beam can transfer a large amount of energy into micro-scale focal region instantaneously to solidify or cure materials in air, therefore enabling high-precision and high-throughput manufacturing for a wide range of materials. In this paper, we introduce laser-based additive manufacturing methods and review the types of lasers widely used in 3D printing machines. Important laser parameters relevant to additive manufacturing will be analyzed and general guidelines for selecting suitable lasers for additive manufacturing will be provided. Discussion on future prospects of laser technologies for additive manufacturing will be finally covered.

Lasers in additive manufacturing: A review

Chemical mechanical planarization (CMP) is a wet polishing technique employed to smooth the surface of various materials using a combination of chemical and mechanical forces to achieve finer and longer lines on semiconductor devices. Among the published papers related to CMP, the CMP metal slurry has been the primary focus, and it appears to be the main driver to improve the CMP performance and quality for next-generation devices. Slurry can affect the removal rate, uniformity, defects, and selectivity between the metal and the barrier layer. The material-removal mechanism of metal CMP is determined by the chemical reaction due to chemical solutions compared to the mechanical action, which is due to the abrasiveness of the slurry. We verify that for each user, a chemical knowledge of slurry is required to obtain preferred results. The basic chemical factors of metal CMP slurry are oxidizers, chelating agents, and corrosion inhibitors. This review focuses on the role and effectiveness of each chemical solution by considering the electrochemical characteristics. It will assist in determining the most appropriate solution to further the development of new slurry for next-generation metal CMP.

Slurry components in metal chemical mechanical planarization (CMP) process: A review

Lubrication is essential for proper and reliable operation of mechanical systems as it is vital to reduce friction and wear of moving components to assure high quality performance. Particularly, with continued development of precision devices the need to acquire effective lubrication technology for micro-systems continues to rise. The challenge lies in the fact that conventional lubrication methods cannot be applied to micro-systems due to viscosity effects. Thus, driven by the needs of precision devices, stringent operating conditions and environmental preservation, numerous alternatives to conventional liquid lubricants have been proposed. In this paper, various lubrication methods to replace or improve conventional liquid lubrication and their characteristics are reviewed. Fundamental mechanism and tribological characteristics of minimum quantity lubrication (MQL), vapor phase lubrication (VPL), and self-assembled monolayer are discussed.

Nano-lubrication: A review

Laser-Assisted milling is a type of thermally-assisted machining process in which a workpiece is locally softened by a laser heat source before machining. This method is effective solution for machining materials such as Inconel series alloys, titanium alloy, and ceramics, which are more difficult to machine compared with conventional materials. It is also a green machining process, because it saves energy by reducing the cutting force. Laser-Assisted milling has only been used in limited fields including single-direction machining of flat surfaces. When the laser-assisted milling has a complex tool-path, it is difficult to control the heat source and cutting tool simultaneously. To apply the process in industrial field studies of workpieces having various shapes are needed. This paper provides a review of current laser-assisted milling devices, and then develops a three-dimensional laser-assisted milling device for complex tool-path machining. A high-power diode laser with additional axes was retrofit to the spindle of a five-axis machining center. The device could be used in industrial fields whose machined products have complicated shapes.

Laser assisted milling device: A review

Manufacturing can be defined as the transformation of raw materials into desired products by various processes, such as machining, welding and coating. Today, laser and arc heat sources are largely used as the means for processing raw materials. The laser is one of the most widely used non-contact thermal energy sources in various processes, and the development of laser processes and devices for effective manufacturing is still ongoing. Arc heat sources are widely used in welding and coating processes. In particular, the types of welding processes using arc heat sources are very different depending on the materials used and the purpose of welding. In this paper, individual processes using laser and arc heat that have been reported over the past five years are reviewed, including machining, welding, sintering and coating. Then, hybrid processes that use laser and arc heat sources together are also reviewed. The final part of this review provides a summary and discusses future trends for individual and hybrid processes using laser and arc heat sources.

Laser and Arc Manufacturing Processes: A Review

We show that crack-free drilled structures with 25 μm hole size can be fabricated in the 12 μm-thick Permalloy foil by a nanosecond ultraviolet laser with low pulse energy and high repetition rate. The number of pulses required for drilling decreased with increasing pulse energy. The obtained hole exhibited a smaller size than the laser spot, implying that only the central part of a focused Gaussian beam contributed to the drilling. Debris and burr incurring as a result of the laser micromachining could be quickly removed by etching in an HCl/HNO3 solution. This made it possible to obtain a clear structure without any debris remaining on the foil. This laserdirect process may be effectively utilized for fabricating fine metal masks necessary for the production of organic light emitting diode displays and other electronic devices.

/pdf/laser-micromachining-of-permalloy-for-fine-metal-mask-8segut8qs5.pdf

Laser micromachining of permalloy for fine metal mask

In this work, we explore the nonenzymatic detection of H2O2 using anodic SnO2 nanoporous channels (NPC) decorated with CuO quantum dots (QDs). The open-top and crack-free morphology of SnO2 NPC was obtained by modified anodization. The samples were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray analysis (EDAX), high-resolution transmission electron microscopy (HRTEM), Raman and X-ray photoelectron (XPS) spectroscopy. FESEM and HRTEM results show that SnO2 has a uniform channel width and pore size with an average diameter of around 40 nm. XRD, EDAX, XPS, Raman, and HRTEM measurements confirm the high purity of anodic SnO2 NPC with successful deposition of CuO QDs. Pristine (SnO2) and hybrid (SnO2-CuO) electrodes were used directly as the nonenzymatic H2O2 biosensor. The hybrid electrode demonstrated an ultrahigh sensitivity of ∼85,250 μA mM–1 cm–2 with an extremely low limit of detection (0.001 μM), broad linear detection ranges of 5–95 and 25–450 μM, and a quick response time (less than 1.9 s) toward H2O2 detection. This can be attributed to the advanced SnO2 nanoporous structure, the reduced band gap, and the formation of additional surface sites as a result of CuO QD decoration. H2O2 measurement in human blood serum demonstrates high sensitivity, good accuracy, and excellent selectivity of the fabricated hybrid electrode compared to the commercially available biosensor. Density functional theory results indicate that the formation of SnO2-CuO is energetically favorable. H2O2 is strongly and selectively adsorbed over the SnO2-CuO nanostructure possessing a large negative adsorption energy (−1.89 eV) and evinces a significant decrease in the band gap (up to 1.59 eV) of the hybrid structure. The fabricated biosensor showed the highest sensitivity, excellent selectivity, good reproducibility, repeatability, and stability, thus confirming it as a favorable candidate for nonenzymatic H2O2 sensing and quantification. 

Anodic SnO2 Nanoporous Channels Functionalized with CuO Quantum Dots for Selective H2O2 Biosensing

Substantial improvement of corrosion resistance of austenitic stainless steel (SS) has been demonstrated with a protective oxide layer formed by the cathodic plasma electrolytic oxidation (CPEO) process. Two distinct layers, a porous-structured outer layer comprising Fe oxides and a compact inner layer comprising Cr oxides, were created on the SS surface after the CPEO process. The thicknesses of the outer and inner layers were approximately 7 μm and 12 μm, respectively, and the oxide layers were fabricated in an exceptionally short time of <30 s. A potentiodynamic polarization analysis exhibited a 65 % decrease in the corrosion current after the formation of the protective oxide layer, verifying the effectiveness of the CPEO treatment on the corrosion resistance of SS. An electrochemical impedance spectroscopy study revealed that the outer layer captured corrosive species due to its porous structure, while the inner layer had high resistance to reactions with corrosive species due to the compact structure of Cr oxides. Additionally, a Rockwell C indentation test demonstrated the robust mechanical property of the protective oxide layer with a strong bonding strength to the substrate. 

Corrosion resistance of austenitic stainless steel using cathodic plasma electrolytic oxidation

In this study, Plasma Electrolytic Oxidation (PEO) technology was adapted to stainless steel for improving its corrosion resistance. Stainless steel is widely used in various fields due to its remarkable properties including high corrosion resistance, excellent weldability, good performance at all temperatures, etc. Although, in the case of nuclear power plants secondary cooling water components, which mainly utilize stainless steel, aggressive environments are situated created. Plenty of corrosive and abrasive species from the coolants attack the component materials to initiate a wide range of corrosion problems such as general corrosion, pitting corrosion, crevice corrosion, and Stress Corrosion Cracking (SCC), etc. In order to protect the substrate from those corrosive environments, a pre-oxidized layer was deposited through an electrochemical process. The technology used in this study, namely PEO, is an advanced surface engineering method that can produce a protective film having an excellent hardness, heat resistance, and adhesiveness with a compact layer. PEO, which is a developed version of the anodization method, utilizes relatively high voltage with a pulse to enhance the properties of the ceramic layer on the surface by heating and quenching repetitive processes. PEO on stainless steel was conducted by cathodic process and plasma discharges were generated through vapor gas envelope insulating film. After the experiment, a variety of characterizations were conducted. Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were firstly utilized to check the surface morphologies and compositions. Then using hot mounting and polishing, the cross-section of the sample was examined to check the oxide layer thickness and chemical composition by depth. By using an X-ray Diffractometer (XRD), the exact crystalline structure of the fabricated film was characterized. The following characterizations were mainly focused on electrochemical corrosion resistance tests. A typical three-electrode cell system was used to conduct the Potentiodynamic Polarization (PDP) technique for evaluating the improvement of general corrosion resistance. With corrosion potential and corrosion current density parameters from the PDP technique, pitting potential was also evaluated to check the pitting corrosion resistance. Lastly, Electrochemical Impedance Spectroscopy (EIS) method was conducted to figure out the corrosion resistance mechanism of the fabricated protective film and support the numerical data from the perspective of corrosion resistance improvement.
 PEO is a simple, fast, and relatively safe surface engineering method that can be applicated to various metal substrates. It is expected to improve diverse properties of the metal materials including corrosion resistance. It can be said that this technology can open a new era in material engineering in a wide range of industrial fields.

Improvement of Corrosion Resistance of Stainless Steel Used in Nuclear Power Plant Cooling Water Components By Plasma Electrolysis

In this paper we show that the photoresist-protective film of a printed circuit board (PCB) can be delaminated from the underlying photoresist layer by a single pulse of a nanosecond laser at 532 nm. After locally peeling the edge of the PCB with a laser beam of 9 mm size, Scotch tape was attached to the irradiated region to peel off the whole protective film. For a certain range of pulse energies the peeling probability was 100%, without leaving any damage. Since the use of a laser in initial delamination is noncontact and nondamaging, it may be more efficiently utilized in the PCB industry than the conventional knurling method based on mechanical pressing.Keywords: Pulsed laser, Laser-driven delaminationOCIS codes: (140.3538) Lasers, Pulsed; (140.3390) Laser materials processing

Laser-Driven Peeling of the Photoresist-Protective Film of a Printed Circuit Board

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Jun Yeon Heo

Author Tools

Chat about Author