Power CO2 Laser Research Articles

Enhancement of low power CO2 laser cutting process for injection molded polycarbonate

Laser cutting technology is a non-contact process that typically is used for industrial manufacturing applications. Laser cut quality is strongly influenced by the cutting processing parameters. In this research, CO2 laser cutting specifications have been investigated by using design of experiments (DOE) with considering laser cutting speed, laser power and focal plane position as process input parameters and kerf geometry dimensions (i.e. top and bottom kerf width, ratio of the upper kerf to lower kerf, upper heat affected zone (HAZ)) and surface roughness of the kerf wall as process output responses. A 60 Watts CO2 laser cutting machine is used for cutting the injection molded samples of polycarbonate sheet with the thickness of 3.2mm. Results reveal that by decreasing the laser focal plane position and laser power, the bottom kerf width will be decreased. Also the bottom kerf width decreases by increasing the cutting speed. As a general result, locating the laser spot point in the depth of the workpiece the laser cutting quality increases. Minimum value of the responses (top kerf, heat affected zone, ratio of the upper kerf to lower kerf, and surface roughness) are considered as optimization criteria. Validating the theoretical results using the experimental tests is carried out in order to analyze the results obtained via software.

Novel improvement glazing depth measurement model for concrete surface treated by CO2 laser

The accuracy of the existing glazing depth measurement models of concrete surface processed by CO2 laser are affected by numerous factors, such as sideways conduction and the inhomogeneous substrate of the concrete; in addition to the environment and measurement approach used and thus error factor is emerged.The empirical glazing surface of concrete samples using (25–100) watt power CO2 laser workstation shows inaccuracy of results matching within the existing calculated model results that cannot be ignored even in low laser power supplied. Thus, in this paper, a new empirical glazing model (IDGM) for glazing depth measurement is derived and verified. The validation process of the proposed model for transvers speed (1, 2, and 3mm/sec) shows that the real time measured values agree with those from the proposed models to within approximately 96%. In addition, it offers the capability to estimate the glazing depth for a wide range of predefined laser power intensity. In addition this model barring costly experimental validation studies, low cost solution and less power consumption.

Design of High Power CO2 Laser Controller Based on DSP Technology

The paper use CPLD chip EPM7812 to output 100 ~ 500Hz pulse signal and the trigger signal source with the single pulse signal, and design IGBT driving circuit with overcurrent and overvoltage protection function and electromagnetic compatibility (EMC) design of using optocoupler HCPL-3120. And for high power CO2 laser is developed, this paper designs a control system of digital signal processor based on DSP technology, and introduce respectively circuit from two aspects: hardware and software core unit control system in detail; in order to overcome the strong electromagnetic interference generated in the working process of laser, we design power filtering, grounding, safety the key data storage of digital filtering, self-recovery, anti-interference design reset. After a long run test, the control system is stable and reliable, and the control response is fast. It is of great practical and popularization value.

Analisis Fabrikasi Desain Passive Mixing Microchannel Perangkat Mikrofluidik Material Acrylic Dengan Laser CO2 Daya Rendah

Microfluidics devices have been applied in the biomedical field to manipulate the tissue fluids in channels with dimensions between 5-500 lm. Microfluidics device manufactured by a microfabrication process consisting of design, microstucturing and back-end processes. One application of microfluidics is a passive mixing microchannel. In this device, the liquid will flow through the channel without any moving parts and the pressure from the outside to produce a fluid mixing. It is important to design the shape of the channel to generate a nice passive mixing microchannel. Low power CO2 laser is used to process microstucturing as cutting tools to produce microfluidic devices on acyilic material. Surface roughness lines were designed to be observed. In this study, the design process channel carried by the experimental method through the parameters that affect the output of the process is the power of laser cutting, cutting speed and design channel. And then the fabrication of microfluidics with back-end processing is done by the process of merging with a thermal bonding method. Finally, From the experimental results, the design of the channel 1 has an influence on all the parameters for surface roughness compared with a channel design 2.

Effect of CO2 laser power intensity on the surface morphology and friction behavior of alumina ceramic brackets

This study aims at reducing frictional resistance of the ceramic brackets by using CO2 laser irradiation. Forty-two polycrystalline Al2 O3 ceramic brackets were randomly divided into six groups of seven samples: a control group B0 (not subjected to laser irradiation) and five groups subjected to irradiation with intensities of 10 (B10), 30 (B30), 70 (B70), 90 (B90), and 110 (B110) J/cm2 . After irradiation, two samples from each group were evaluated by scanning electron microscopy (SEM) and atomic force microscopy (AFM), while the remaining five samples were tested for frictional resistance. The sliding friction of stainless steel wires (SS-wires) in the brackets was measured using a universal testing machine. Samples from the first set (groups B0, B10, and B30) were significantly more resistant to wire sliding than the samples from the second set (groups B70, B90, and B110). The SEM analysis shows different degrees of blister formation on the bracket surfaces subjected to laser irradiation and no changes in their grain sizes. The AFM results indicate more consistent blister formation for groups B70, B90, and B110 than for other groups. Different CO2 laser power intensities significantly affect frictional resistances of SS-wires in Al2 O3 ceramic brackets.

A simple digital control system with field-programmable gate array for stabilization of CO2 laser output.

A simple digital control system was designed to stabilize CO2 laser based on digital signal processing with the Field-Programmable Gate Array (FPGA) controlling chip and Very-High-Speed Integrated Circuit Hardware Description Language program. In this system, the control parameters were easily determined by software real-time control, and the control circuit was also designed compactly. In addition, the theoretical analysis on the stabilization of CO2 laser output characteristics was presented based on the photoacoustic effect, and the corresponding experiments on the stabilization of CO2 laser output characteristics were further performed. The results show that the output power of CO2 laser is stabilized at the peak with a relative power stability of 2.71%. Furthermore, the frequency of CO2 laser 9P(36) line is stabilized at the center of the laser gain curve with a relative stability of (1.57 ± 0.37)×10-8. This system has a potential of further improvements by optimizing the algorithm and choosing higher-speed signal processor.

Low power CO2 laser modified iron/nickel alloyed pure aluminum surface: Evaluation of structural and mechanical properties

Surface modification of metals is demanding for high strength industrial purposes. Weak mechanical properties of aluminum (Al) are disadvantageous for several applications and needs improvement. We modify the surface of pure Al substrate by alloying it with a thick layer of Fe-Ni, where a low power (27 watt) cw CO2 laser with varying exposure time (30, 40 and 50s) is used. The exposure time dependent microstructure, surface morphology, and surface hardness of the achieved inter-metallic alloyed samples are determined. Microstructure analysis revealed the formation of different phases (Al0.9Ni1.1, AlNi3, Al6Fe, AlFe3, Al5Fe2 and Al76.8Fe14, Al5FeNi) with chemical heterogeneity. Alloyed sample displayed enhanced surface hardness (varied from 27HV0.1 to 53.9HV0.1) for extended laser radiation exposure time (from 30 to 50s). A new inter-metallic compound aluminum-iron-nickel (Al-Fe-Ni) with considerably tougher surface is achieved. Our observations may contribute towards the development of laser assisted modification of metal surface alloying.

Relieving Pain in Oral Lesions of Pemphigus Vulgaris Using the Non-ablative, Non-thermal, CO2 Laser Therapy (NTCLT): Preliminary Results of a Novel Approach.

Introduction: Pemphigus vulgaris (PV) is a chronic, serious autoimmune mucocutaneous bullous disease. Oral lesions in PV may be extremely painful. This pain may adversely affect the patients' oral intake and quality of life. This before-after clinical trial was designed to assess the pain relieving effects of single session of non-ablative, non-thermal CO2 laser therapy (NTCLT) in oral lesions of PV. Methods: Fifty painful oral lesions of fourteen patients with PV were illuminated by CO2 laser (power: 1 W, scanning the lesions with rapid circular motion of the handpiece) passing through a thick layer of transparent gel with high water content. The pain severity of the oral lesions was reported by the patients up to the fourth postoperative day. They were also asked to continue their existing systemic treatment during the course of this study as a precondition for the participation. Results: The severity of contact and non-stimulate (non-contact) pain declined immediately and significantly after NTCLT (P < 0.001). The pain relieving effect was sustained during the four successive days of follow-up. The procedure was pain free and no kind of analgesics was required. Following NTCLT, there were no visible thermal complications such as destruction, ablation or irritation of the oral lesions. Conclusion: The results of the trial proposed that single session of NTCLT could immediately and significantly relieve pain in oral lesions of PV, without any visible thermal complications.

大功率CO2激光器输出窗口热性能分析

大功率CO₂激光器输出窗口热性能分析

大功率CO2激光器输出窗口热性能分析

大功率CO₂激光器输出窗口热性能分析

Optimization of CO2laser welding process parameters of PP/EPDM/Clay nanocomposite using response surface methodology

In recent years, polymer – based nanocomposites have found wide applications in various industries. Polypropylene / ethylene – propylene - diene monomer /Nanoclay (PP/EPDM/Nanoclay) nanocomposite is one of these materials that has many applications in automotive and aircraft industries. Welding as a fabrication process has attracted the attention of researchers for joining these materials. Among welding processes, laser welding because of its advantages can be a choice for joining of PP/EPDM/Nanoclay nanocomposites. In this paper, the effect of CO2 laser power, scan velocity, stand-off distance and clay content on impact strength of butt-welded PP/EPDM/Nanoclay 3.2 mm sheets is investigated. The response surface methodology (RSM) is used to develop a statistical model relating the above parameters to the impact strength of the weld joint. The results indicated that increase in clay content and scan velocity decreased the impact strength whereas stand-off distance increased it. The maximum impact strength of 70 J/m is achieved at laser power of about 103 W, velocity of 400 mm.min-1, stand-off-distance 8 mm and clay content of about 1.3% wt.

STUDYING PHOTOKINETICS OF THE IR LASER RADIATION EFFECT ON MIXTURE OF THE CO2-N2-H2O GASES FOR DIFFERENT ATMOSPHERIC MODELS

A kinetics of energy exchange in the mixture of the atmosphere CO2-N2-H2O gases under passing the powerful CO2 laser radiation pulses within the three-mode model of kinetical processes is studied. More accurate data for the absorption coefficient are presented.

Fabrication of microchannels on PMMA using a low power CO2 laser

This study presents a cheap and quick method for the formation of microchannels on poly methyl methacrylate (PMMA). A continuous wave CO2 laser with a wavelength of 10.6 μm was used to inscribe periodic ripple structures on a PMMA substrate. A direct writing technique was employed for micromachining. As PMMA is very sensitive to such laser irradiations, a slightly low power CO2 laser was effective in inscribing such periodic structures. The results show that smooth and fine ripple structures can be fabricated by controlling the input laser parameters and interaction time of the laser beam. This direct laser writing technique is promising enough to prevent us from using complex optical arrangements. Laser power was tested starting from the ablation threshold and was gradually increased, together with the variation in scanning speed of the xy-translational stage, to observe the effects on the target surface in terms of depth and width of trenches. It was observed that the depth of the trenches increases on increasing the laser power, and the bulge formation on the outer sides of the trenches was also studied. It was evident that the formation of bulges across the trenches is dependent on the scanning speed and input laser power. The results depict that a focused laser beam with optimized parameters, such as controlling the scanning speed and laser power, results in fine, regular and tidy periodic structures.

Properties and Microstructure of Laser Welded VM12-SHC Steel Pipes Joints

Abstract Paper presents results of microstructure and tests of welded joints of new generation VM12-SHC martensitic steel using high power CO2 laser (LBW method) with bifocal welding head. VM12-SHC is dedicated to energetic installation material, designed to replace currently used. High content of chromium and others alloying elements improve its resistance and strength characteristic. Use of VM12-SHC steel for production of the superheaters, heating chambers and walls in steam boilers resulted in various weldability researches. In article are presented results of destructive and non-destructive tests. For destructive: static bending and Vickers hardness tests, and for non-destructive: VT, RT, UT, micro and macroscopic tests were performed.

Rapid prototyping of biodegradable microneedle arrays by integrating CO2 laser processing and polymer molding

An integrated technology of CO2 laser processing and polymer molding has been demonstrated for the rapid prototyping of biodegradable poly-lactic-co-glycolic acid (PLGA) microneedle arrays. Rapid and low-cost CO2 laser processing was used for the fabrication of a high-aspect-ratio microneedle master mold instead of conventional time-consuming and expensive photolithography and etching processes. It is crucial to use flexible polydimethylsiloxane (PDMS) to detach PLGA. However, the direct CO2 laser-ablated PDMS could generate poor surfaces with bulges, scorches, re-solidification and shrinkage. Here, we have combined the polymethyl methacrylate (PMMA) ablation and two-step PDMS casting process to form a PDMS female microneedle mold to eliminate the problem of direct ablation. A self-assembled monolayer polyethylene glycol was coated to prevent stiction between the two PDMS layers during the peeling-off step in the PDMS-to-PDMS replication. Then the PLGA microneedle array was successfully released by bending the second-cast PDMS mold with flexibility and hydrophobic property. The depth of the polymer microneedles can range from hundreds of micrometers to millimeters. It is linked to the PMMA pattern profile and can be adjusted by CO2 laser power and scanning speed. The proposed integration process is maskless, simple and low-cost for rapid prototyping with a reusable mold.

Glass-on-Glass Fabrication of Bottle-Shaped Tunable Microlasers and their Applications.

We describe a novel method for making microbottle-shaped lasers by using a CO2 laser to melt Er:Yb glass onto silica microcapillaries or fibres. This is realised by the fact that the two glasses have different melting points. The CO2 laser power is controlled to flow the doped glass around the silica cylinder. In the case of a capillary, the resulting geometry is a hollow, microbottle-shaped resonator. This is a simple method for fabricating a number of glass whispering gallery mode (WGM) lasers with a wide range of sizes on a single, micron-scale structure. The Er:Yb doped glass outer layer is pumped at 980 nm via a tapered optical fibre and WGM lasing is recorded around 1535 nm. This structure facilitates a new way to thermo-optically tune the microlaser modes by passing gas through the capillary. The cooling effect of the gas flow shifts the WGMs towards shorter wavelengths and thermal tuning of the lasing modes over 70 GHz is achieved. Results are fitted using the theory of hot wire anemometry, allowing the flow rate to be calibrated with a flow sensitivity as high as 72 GHz/sccm. Strain tuning of the microlaser modes by up to 60 GHz is also demonstrated.

Analisis Fabrikasi Desain Lamination Passive Mixing Microchannel Perangkat Mikrofluidik AcrylicMenggunakan Laser CO Daya Rendah

Microfluidics device has been applied in the biomedical fields to manipulate fluids in a channel network with the dimensions between 5-500 µm. Microfluidics device is manufactured by microfabrication process consists ofdesign, microstucturing and back-end process. One of microfluidics application is passive mixing microchannel. Inthis device, the fluids will flow through the channel without any moving part and pressure from outside to producemixing fluid. It is important to design the form of channel to produce a good lamination passive mixingmicrochannel. In this study, the process of channel design was performed. Low power CO2 laser was used formicrostucturing process as a cutting tool to produce microfluidic device on acrylic material. The parameters affectthe output of the cutting process are the laser power, cutting speed and the design of channel. Surface roughness ofdesigned channel was observed. Finally, back-end process was performed by joining process using thermalbonding method. From the experimental results, the design of lamination channel has an influence on allparameters to the surface roughnes.

Research on Characteristic Parameter of Ta-Zro2 Fiber Blackbody Cavity Temperature Sensor

By sputtering and plasma spraying technology, a sapphire optical fiber blackbody cavity temperature sensor of tantalum (melting point is 2997℃) - zirconium oxide (melting point is 2715℃) thin film was developed. Static calibration system for the sensor to measure target temperature 1721 ℃ is also designed by using three oxygen (produced by water electrolysis) flame guns. When its impact resistant capacity is more than 50MPa, the corresponding temperature is 2802 ℃ . A high power and high frequency modulation CO2 laser pulse is used as exciting source to heat it to 1500℃, and the dynamic calibration device is designed independently, thus this sensor in experimental results show a time response on the order of μs. Signal collection and transmission through fiber optic cable are proposed, which can meet the need of transient high temperature measurement in harsh environment.

Impact of CO2 laser and stannous fluoride on primary tooth erosion.

This study evaluated in vitro the effect of input power of CO2 laser, either associated or not to stannous fluoride (SnF2) gel, for the control of intrinsic erosion in primary teeth. One hundred four enamel slabs (3 × 3 × 2 mm) from human primary molars were flattened and polished. Adhesive tapes were placed on their surface leaving a window of 3 × 1 mm. Slabs were then cycled four times in 0.01 M hydrochloric acid (pH 2, 2 min) and in artificial saliva (2 h) for creation of erosive lesions. Specimens were randomly assigned into eight groups (n = 13) according to fluoride application [absent (control) or 0.4% stannous fluoride gel (SnF2)] and input power of CO2 laser [unlased (control), 0.5, 1.0 or 1.5 W]. The CO2 laser irradiation was performed in an ultra-pulse mode (100 μs of pulse duration), 4-mm working distance, for 10 s. Specimens were then submitted to further erosive episodes for 5 days and evaluated for enamel relative permeability. Fluoride did not show any protective effect for any of the laser-treated groups or control (p = 0.185). However, a significant effect was detected for input power of CO2 laser (p = 0.037). Tukey's test showed that there was a significant statistically difference between specimens irradiated with 0.5 and 1.5 W (p = 0.028). The input power of 0.5 W showed lower permeability. Variation of input power CO2 laser can influence enamel permeability, at the power of 1.5 W which promoted greater permeability.

BESTIA – The next generation ultra-fast CO2 laser for advanced accelerator research

Over the last two decades, BNL׳s ATF has pioneered the use of high-peak power CO2 lasers for research in advanced accelerators and radiation sources. Our recent developments in ion acceleration, Compton scattering, and IFELs have further underscored the benefits from expanding the landscape of strong-field laser interactions deeper into the mid-infrared (MIR) range of wavelengths. This extension validates our ongoing efforts in advancing CO2 laser technology, which we report here. Our next-generation, multi-terawatt, femtosecond CO2 laser will open new opportunities for studying ultra-relativistic laser interactions with plasma in the MIR spectral domain, including new regimes in the particle acceleration of ions and electrons.