Laser Microperforation Research Articles

The Electromagnetic Noise Level Influence on the Laser Micro-Perforation Process Specific to Automotive Components.

This article focuses on the influence of generated electromagnetic noise (energy) during the micro-perforation process. This study aims to investigate the critical parameters and effects of using laser technology in the processing of textile materials for airbags. Different levels of electromagnetic noise and material thicknesses were investigated to ensure the quality of manufactured parts and the best component performance. A factorial analysis (DOE) was developed to evaluate the influence of electromagnetic noise levels over pull test results and its effect on the micro-perforation process. The overall inferential analysis concludes a significant influence of the noise levels on micro-perforation processing. The detailed analysis suggests that 1.2 V is an optimal level of electromagnetic noise where the material maintains its mechanical properties in a more predictable and consistent manner. Additionally, the factorial design provides significant evidence for an interaction and main effects' influences of analyzed factors. The obtained results in this study have demonstrated that monitoring and controlling the noise level have beneficial effects over the laser processing. This ensures that the safety aspect of the produced parts is entirely upheld and protected. Also, this research contributes to improving the manufacturing process and ensures that high-quality products are obtained, being suitable for use in sensitive applications such as automotive airbags.

Improvement of multilayer plastic delamination using surface modification

Multilayer flexible packaging waste (MFPW) represents a critical issue in the field of waste management. The heterogeneous composition of this type of plastic makes its recyclability challenging. In this context, the delamination process appears to be a promising way to recycle the polymers layers separately. However, this process is still limited for a few MFPW.This work propose an innovative way to improve the delamination process using three surface modification techniques (mechanical and laser microperforation (µP), and abrasion) on the MFPW surface in order to accelerate the diffusion of the dissolving agent. The delamination was tested in a 10 % sodium hydroxide solution at 25ºC.Under this study, the mechanical µP and the abrasion gave the best results of delamination compared to the laser µP (total delamination in 25 min vs 45 min, respectively). It was concluded that the distance between the microholes was an important factor in both µP techniques.

Effect of CO2 Laser Microperforation Pretreatment on the Dehydration of Apple Slices during Refractive Window Drying.

This research studied the use of CO2 LASER microperforation as a pretreatment for the refractive window (RW) drying of apple slices with respect to total polyphenol content (TPC), antioxidant capacity, color ΔE, and product stability under accelerated storage. For this purpose, the processing variables assessed were pore size (200-600 µm), pore density (9-25 pores/cm2), and drying temperature (70-90 °C). As baseline criteria, a comparison with respect to the control without microperforations and samples subjected to conventional tunnel and lyophilization were also considered. The increase in the pore size from 200 to 600 µm resulted in shorter drying times (≤40 min), minimal change in color (ΔE) and loss of TPC, while DPPH was negatively affected by the combined effect of the pore density and the drying temperature. In general, the use of RW with CO2 resulted in apples of higher quality than those obtained in conventional drying and comparable to those obtained through the use of freeze-drying. Finally, during accelerated storage, quality attributes decreased significantly for samples dried at 90 °C regardless of whether microperforations were used, suggesting that a compromise between drying temperature and pore size must be weighed to reduce processing time and to avoid further quality losses during storage.

Laser Microperforation Assisted Drug-Elution from Biodegradable Films.

In a modern high-tech medicine, drug-eluting polymer coatings are actively used to solve a wide range of problems, including the prevention of post-surgery infection, inflammatory, restenosis, thrombosis and many other implant-associated complications. For major assumptions, the drug elution mechanism is considered mainly to be driven by the degradation of the polymer matrix. This process is very environmentally dependent, unpredictable and often leads to a non-linear drug release kinetic. In the present work, we demonstrate how the laser microperforation of cargo-loaded biodegradable films could be used as a tool to achieve zero-order release kinetics with different elution rates. The effects of the laser-induced hole’s diameter (10, 18, 22, 24 µm) and their density (0, 1, 2, 4 per sample) on release kinetic are studied. The linear dynamics of elution was measured for all perforation densities. Release rates were estimated to be 0.018 ± 0.01 µg/day, 0.211 ± 0.08 µg/day, 0.681 ± 0.1 µg/day and 1.19 ± 0.12 µg/day for groups with 0, 1, 2, 4 microperforations, respectively. The role of biodegradation of the polymer matrix is reduced only to the decomposition of the film over time with no major influence on elution rates.

Exploring The Potential Acceleration of Granny Smith Apple Drying By Pre-Treatment With CO2 Laser Microperforation

Exploring The Potential Acceleration of Granny Smith Apple Drying By Pre-Treatment With CO2 Laser Microperforation

Effect of pulsed vacuum and laser microperforations on the potential acceleration of chicken meat marination

AbstractChicken meat marination has become a fundamental process in the poultry industry since it provides a product with better sensory attributes. The objective of this study was to examine the effect ofCO2laser microperforation coupled with vacuum impregnation treatment on the marination processing time of chicken breasts and to mathematically analyze the marinade diffusion process using Fick's second law and an anomalous diffusion model. Cylindrical cuts of unmarinated chicken meat wereCO2‐laser microperforated with pores of 228 μm and marinated under vacuum pressure (15 kPa) with NaCl (3% wt/wt) and sodium tripolyphosphate (1% wt/wt) during 60 hr at6 ° C. The chicken:brine ratio was 1:11 wt/wt. Mass gain, moisture content, and salt concentration were determined over time; furthermore, effective diffusion coefficient (Deff) was obtained using Fick's second law and anomalous diffusion models. Marinade diffusion into chicken cuts was favored by microperforation combined with vacuum pulses, reduction processing time in 34%. TheDeffranged between1.46 × 10−10and2.08 × 10−10m2/sfor Fick's second law and between2.27 × 10−10and4.23 × 10−10m2/sαfor anomalous diffusion model, withα−values close to 1. In conclusion, the results showed no significant difference between the models, which was attributed to the homogeneity of the chicken tissue.Practical ApplicationsChicken meat marination has become a fundamental process in the poultry industry since it provides a product with better sensory attributes and shelf life than unmarinated chicken meat. Nevertheless, marination is a process that requires a long processing time to obtain a specified salt content in the meat. In this sense, laser microperforation of the meat is a treatment that when coupled with vacuum impregnation, can accelerate the marinating process of poultry meat. When simultaneously applying both technologies, the processing time was reduced by 6 hr compared with the control (almost 34%), which will allow a significant increase in plant productivity.

Application of vacuum impregnation and CO2-laser microperforations in the potential acceleration of the pork marinating process

The marination of meat takes many hours to attain the required salt content. Vacuum impregnation (VI) and CO2-laser microperforation have been studied to accelerate the mass transfer process and show promising results. The objective of this study was to investigate the feasibility of reducing the pork marinating time by coupling CO2-laser microperforation and VI processes and mathematically with Fick's second law and anomalous diffusion models. Pork cylinders were microperforated and marinated with a solution containing NaCl (8% w/w) and Na5P3O10 (0.3% w/w) at 6 °C for 60 h. The marinating process was modeled using Fick's second law and anomalous diffusion models. The marinating process coupling VI and microperforations significantly accelerated the mass transfer compared with that of the conventional salting process, reducing the marinating processing time by 47.8%. The anomalous diffusion model was better at representing and adjusting the experimental data compared than the model based on Fick's second law. Industrial applicationThe marinating of meat is a process commonly applied in the meat industry, which focuses on enhancing the flavor, tenderness and juiciness of meat. However, it is a time-consuming process. Laser microperforation is a pretreatment performed on the meat in which the laser acts as a drill, creating micropores in the meat, which coupled with vacuum impregnation can be applied to accelerate the marinating process of pork meat. Applying both technologies, it is possible to reduce the processing time by almost 48%, which can relevantly and significantly increase plant productivity.

Direct Laser Microperforation of Bioresponsive Surface-Patterned Films with Through-Hole Arrays for Vascular Tissue-Engineering Application.

Tissue architecture plays critical roles in the physiological functions of blood vessels. Surface-patterned films are promising to replicate cellular alignment as in the native vessels. However, for vascular tissue engineering (TE) applications, the current surface-patterned films lack structural support for the myoendothelial communications between tunica media and intima. Herein, we report the development of direct microperforation using a femtosecond laser on surface-patterned films for the native-like architecture reconstruction of blood vessels. Poly(ε-caprolactone) (PCL) thin films were surface-patterned with anisotropic microridges/grooves. Direct femtosecond laser ablation further resulted in microscale through-holes for the PCL films, without invasive thermal damage to the ridges/grooves on the nonprocessed surface. Laser fluence and pulse number were observed to significantly influence the microperforation on both hole quality and dimension. The PCL films after direct femtosecond laser microperforation exhibited improved flexible properties, without sacrificing the yield stress. Meanwhile, direct femtosecond laser microperforation resulted in PCL films with hydrophilic permeability to transport nutritional/signaling biomolecules and allowed for heterocellular protrusion ingrowth into the through-holes for physical myoendothelial contacts. Small-diameter vascular TE scaffolds based on the as-fabricated PCL films could enable a hybrid vascular wall construction with aligned stromal multilayers and a confluent endothelium similar to those of the native vascular tissue. These results showed that direct femtosecond laser microperforation could be a reliable approach for producing biomimetic films with through-holes. The developed vascular TE scaffolds with microridges/grooves and through-holes have the potential to offer structural support for vascular architecture reconstruction with the native-like stromal and endothelial components.

Optimized PLA-based EMAP systems for horticultural produce designed to regulate the targeted in-package atmosphere

An innovative biodegradable bio-based film packaging system has been designed to achieve equilibrium modified atmosphere packaging (EMAP) of high value fresh horticultural produce through tuning the packaging barrier properties combining laser micro-perforation, breathable membrane technologies and materials. The tested commodities were cherry tomatoes and peaches. Laser micro-perforated 30μm polylactic acid (PLA) film was used as the main bio-based packaging material. Key parameters of the novel bio-based EMAP system for the selected horticultural produce were optimized in terms of performance and cost reduction. Laboratory experiments were employed in order to validate the optimal design of the innovative EMA package. Results from lab experiments show improved efficiency of the optimized PLA based EMAP system in prolonging the shelf-life time of horticultural commodities as compared to non-packed commodities and commodities packed with conventional oriented polypropylene (OPP) film. The exposure of the PLA film to the EMA packed fresh produce conditions during the shelf-life period has negligible effect on the mechanical, physical and chemical properties of the film.

The Technique of Enhancing the Transdermal Penetration for the Gold Nanoparticles and Perspectives of Application

Background: In recent years, worldwide attention of researchers focused on the practical implementation of nanoscale materials in biomedical technology. It’s proved that intravenous injected gold nanoparticles are accumulated in tumor tissues. However, when gold nanoparticles injected intravenously negative effects in the internal organs of experimental animals are observed. 160 nm diameter particles affect the wall of blood vessels, resulting in vacuolar degeneration of endothelial cells. Particles with a diameter of 50 nm lead to more expressed changes in the internal organs. Injection of the particles diameter of 15 nm causes moderate degeneration of parenchymal cells of internal organs and circulatory disorders. Materials and Methods: In current research, for the first time using the methods of experimental pathology the permeability of intact and damaged skin for nanoscale gold particles in combination with organosulfur compounds—imethylsulfoxide and tiofansulfoxide were studied. We used 140 male outbred white rats with an average weight 150 - 200 grams. All the animals were divided into one control and three experimental groups. Results: Laser microperforation skin with ultrasound treatment can provide good skin permeability, but in contrast to use of agents with organosulfur compounds inflammatory reaction, the destruction of superficial and deep skin tissue structural elements are observed. The comparative efficacy of dimethylsulfoxide and tiofansulfoxide for transdermal permeability of gold nanoparticles was studied. It’s proved that in topical application solution of nanoparticles with organosulfur compounds negative effects of the accumulation of nanoparticles in the internal organs, disorders of organ and tissue microcirculation, development in the degenerative changes are not observed. We found that the depth of penetration of damaged skin (contact dermatitis) for the gold nanoparticles in combination with organosulfur compounds, and ultrasound exposure is substantially higher than the penetration of intact skin.

Complex of laser processing techniques for production of fine-meshed grids of refractory materials

Laser processing techniques were used for production of fine-meshed control grids for cathode assemblies. In this paper we discuss the features of development and production of grids made of refractory materials with concentric arrangement of meshes and wires. Two different types of grid structures are studied: a pyrographite grid with thin wires and a molybdenum grid with small round meshes. The grid with concentric arrangement of meshes is connected with multibeam field-emission cathode which is also produced by laser processing techniques. High-performance, high-speed laser microperforation allows one to obtain high convergence between grid and cathode. The paper also contains an estimation of the defect zone size after the action of the laser.

Influence of Mie-scattering on high-speed micro-perforation considering brilliant laser radiation

High-speed laser micro-perforation (“on-the-fly” technique) represents a processing technique for the time-efficient and cost-effective production of microsieves. In order to increase the perforation rate this process is researched with use of a brilliant laser source. These laser sources combine ample output power with an excellent beam quality. The high perforation rate [<50 000 drillings/s, laser source: YLR-300SM (IPG)], which can be achieved with this technique makes it an attractive option for the creation of large drilling matrices and drilling widths of less than 15 μm. The described experimental work is carried out to validate a theoretical analysis of the maximum obtainable perforation rate and its main influencing factors. It was found that Mie-scattering represents a crucial factor for the whole process with respect to the application of a brilliant laser source.

Thermo-ductile composites: new materials for 21st century manufacturing—micro-perforation symmetry

New thermo-ductile composite materials with highly aligned discontinuous fibre reinforcement are being developed for the manufacture of light weight structural parts. Their enhanced formability and high specific stiffness make them interesting candidates for metal substitution in the cost effective volume manufacturing of lightweight structural parts. These new discontinuous fibre materials are produced by laser micro-perforation of pre-impregnated unidirectional composite precursors. The process converts the composite into a mass of small aggregates made up of aligned discontinuous fibres, otherwise called fibre domains, which become the key micro-structural participants in subsequent deformation processes. Micro-perforation is an inherently flexible process, which can convert a single composite precursor into a wide range of products. The treatment may be overall or only applied to those parts of the structure that need to exhibit enhanced formability. The induced fibre length may be consistent throughout the material or may be varied between different parts of the structure. In this paper the symmetry considerations underlying the selection of the micro-perforation patterns are discussed.

Non-enzymatic access to the plasma membrane of Medicago root hairs by laser microsurgery

Using UV laser microsurgery, the cell walls of root hairs from Medicago sativa (alfalfa) were perforated under plasmolysing conditions, giving direct access to the plasma membrane without enzyme treatment. The opening in the cell wall of a few micrometre in diameter results in immediate movement of the protoplasm and partial or complete extrusion of the cell contents. The movement of the protoplasm is retarded by increases in calcium concentration. The calcium-dependency of the movement of the protoplasm allows us to obtain preferentially the extrusion of protoplasm, or to gain access to a small area of plasma membrane in situ. The complete protoplasm can be expelled, to form a protoplast. Fluorescein diacetate staining indicated esterase activity and membrane integrity of the protoplasts. Microscopic examination revealed organelle movement and the presence of a nucleus. The plasma membrane was free from cell wall fragments, as shown by Tinopal staining. Conditions for obtaining plasmolysis without disturbing the physiology of the root hairs too much were achieved by slow, stepwise and reversible plasmolysis. Cytoplasmic streaming in root hairs was maintained during plasmolysis and laser microperforation. This laser technique should be suitable for the performance of electrophysiological studies using the patch-clamp technique on plasma membrane from non-enzyme-treated cells.