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This paper provides a quantitative and qualitative assessment of the effects of electroplating on polymer parts made by stereolithography (SL) and laser sintering. A series of test samples were coated with copper and nickel with varying thickness. Thicker coatings (120 μm) were reproduced with a repeatability that should not adversely affect the tolerances with which such parts may be produced given the tolerances of the initial rapid prototyping processes themselves. Thinner coatings (20 μm) resulted in a smother surface finish than thicker coatings for SL parts, however the converse was true for laser‐sintered parts. Composite theory was used to predict that thicker coating would lead to higher Young's modulus in parts and this was shown to be true in physical tests although the practical values were lower than the predicted values especially for thicker coatings. Physical tests also confirmed that thicker coatings increased UTS and impact energy but had a minimal effect on the ductility of parts.

The purpose of this paper is to discuss laser cutting of FR4, and BT/Epoxy‐based PCB substrates with 355 nm DPSS UV laser.

The effects of various laser conditions such as scanning speed, assisting gas, repetition rate and interval between scans on the heat affected zone (HAZ) and charring are studied. The quality and morphology of laser cut PCB substrates are analyzed with optical microscopy, and scanning electron microscopy (SEM). Also, the laser cut PCB substrates are evaluated by humidity testing and thermal cycle testing.

Multi‐pass cutting at high scanning speed, with O₂ assist gas was found to be able to achieve high quality cutting with little charring. It was also found that a certain time interval between scans and higher repetition rates led to a reduced heat affected zone and less charring.

This paper demonstrates high quality laser cutting of PCB substrates with no delamination, little charring and minimum HAZ. The developed process has important potential applications in the electronics industry.

The purpose of this paper is to demonstrate laser microvia drilling of polyimide thin films from multiple sources before metallic sputtering. This process flow reduces Flexible Printed Circuit Board (FPCB) material, chemical and operational costs by 90 per cent in the construction of flexible circuits.

The UV laser percussion drilling of microvias in 25 μm thick polyimide films with low coefficients of thermal expansion (CTE) and elastic modulii was investigated. Results were obtained using Scanning Electron Microscopy and Surface Profilometry. Polyimide films tested included: Dupont™ Kapton^® EN; Kolon^® GP and LV; Apical^® NPI; and Taimide™ TA‐T.

There was no direct relationship between the top and bottom diameters and ablation depth rates between the polyimide films tested using the same test conditions. There was a direct relationship with exit diameters and etch rates at different laser pulse frequency rates and fluence levels. Laser pulse rates at 30 kHz produced 20 per cent larger exit diameters than at 70 kHz, however at 70 kHz the first pulse etched 16.5 per cent more material. High fluence levels etched more material but with a lower etch efficiency rate. Other microvia quality concerns such as surface swelling, membrane residues on the bottom side and surface debris inside the microvias were observed. Nanoscale powder‐like surface debris was observed on all samples in all test conditions.

This is the first comparison of material specifications and costs for films from multiple polyimide manufactures and laser microvia drilling. The paper also is the first to demonstrate results using a JDSU™ Lightwave Q302^® laser rail. The results provide the first insights into potential microvia membrane issues and debris characteristics.

The melt pool created by a laser is one of the most important factors affecting the quality of the deposit in a laser metal deposition (LMD) process. The high‐intensity infrared (IR) radiation emitted by the melt pool saturates a conventional camera sensor preventing useful data acquisition. The purpose of this paper is to discuss the development of a low‐cost vision system to monitor the size of the melt pool for in‐process quality control of the deposit.

According to the black body radiation theory, there is no radiation emitted in the ultraviolet (UV) region from the melt pool created in the LMD process. IR radiation and visible light are the only radiations inherent to the LMD process. UV illumination is utilized along with narrow band pass filters on a USB camera to achieve a clear image of the melt pool while IR radiation of the process is blocked out. The melt pool size and shape were closely monitored during the deposition process.

A clear image of the melt pool was obtained using a relatively low‐cost imaging system during laser deposition process.

Traditional approaches to vision systems in high‐intensity processes use a high‐speed video camera fitted with IR filters to prevent saturation of the camera sensor. Such systems are usually complex and expensive to run and maintain. This paper demonstrates an alternative and lower cost method to achieve in process monitoring in an LMD process.

The purpose of this paper is to study the effect of laser fluence on the post‐transfer cell viability of human colon cancer cells (HT‐29) during a typical biofabrication process, matrix‐assisted pulsed‐laser evaporation direct‐write (MAPLE DW).

The post‐transfer cell viability in MAPLE DW depends on various operation conditions such as the applied laser fluence. HT‐29 cell was selected as a model mammalian cell to investigate the effect of laser fluence on the post‐transfer cell viability. MAPLE DW‐based HT‐29 cell direct writing was implemented using an ArF excimer laser under a wide range of laser fluence. Trypan blue dye‐exclusion was used to test the post‐transfer cell viability.

It has been observed that: the HT‐29 cell viability decreases from 95 to 78 percent as the laser fluence increases from 258 to 1,482 mJ/cm²; and cell injury in this study is mainly due to the process‐induced mechanical stress during the cell droplet formation and landing processes while the effects of thermal influence and ultraviolet radiation are below the level of detection.

This paper reveals some interesting relationships between the laser fluence and the post‐transfer mammalian cell viability and injury, and the resulting knowledge of these process‐related relationships helps the wide implementation of MAPLE DW‐based biofabrication. Post‐transfer cell injury reversibility and cell proliferation capacity need to be further elucidated.

This paper will help the wide implementation of cell direct‐write technologies including MAPLE DW to fabricate biological constructs as artificial tissues/organs and bio‐sensing devices.

The shortage of donor organs and the need of various bio‐sensing devices have significantly prompted the development of various biological material‐based direct‐write technologies. Process‐induced cell injury happens during fabricating of biological constructs using different direct‐write technologies including MAPLE DW. The post‐transfer cell viability is a key index to evaluate the feasibility and efficiency of any biofabrication technique. This paper has investigated the effect of laser fluence on the post‐transfer HT‐29 cell viability and injury. The knowledge from this study will help effectively and efficiently fabricate various biological constructs for organ printing and biosensor fabrication applications.

The importance of radiation curing was emphasised in the United States in 1984 when over 11,000 people specialising in this area — either a manufacturer or user attended a conference on the subject. Obviously interest is high.

In the Earth’s upper atmosphere, damage to satellite electronics is caused by exposure to extreme ultraviolet (EUV) radiation. One particular region where this type of radiation occurs is the South Atlantic Magnetic Anomaly region. As a result, there is a need to design and develop a sensor which could be used to investigate the flux and energy levels of radiation in this region. To do so, the aim of this study is to characterise the sensor and its electric response to typical EUV radiation levels based on the photoelectric effect principle.

For this purpose, a copper plate planar sensor prototype with dimensions that fit on the sides of a one-unit (1U) CubeSat was constructed. The sensor prototype was placed in a vacuum chamber and was subjected to continuous radiation from a vacuum ultraviolet deuterium light source at test facilities available in the Western Cape region (South Africa). Subsequently, the terminal voltage of the sensor was measured and compared with theory.

The measured time-averaged terminal voltages indicate the generation of photocurrents of the order of 1 μA, which is consistent with theory.

Conclusively, these results validate the measurement approach and operation of the sensor, which can be used to design a 1U CubeSat sensor that measures EUV radiation in low Earth orbit.

The need for a small, low cost, simple, personal UVR detector has been motivated by the growing concerns about adverse health effects induced by UV radiation. SolarTech Enterprises, LLC has developed several such photochromic detectors for UV radiation detection. Broadband detectors (290nm to 400nm) and wavelength specific detectors for UVB and UVA regions of the spectrum have all been developed by SolarTech.

Examines the use of power beams to prepare surfaces prior to adhesive bonding. Describes the current surface treatments available and discusses their limitations. Outlines how power beam techniques for surface modification of polymeric and metallic adherends has the potential to overcome many of these problems. Also looks at the emerging technology of using radiation‐curable adhesives based on ultraviolet, visible light and electron beams, which have the advantages of fast rates of cure, improved quality of finished products and the absence of any volatile organic compounds.