Study of Overlapping Adjacent Jets for Effective Laser-Induced Forward Transfer Printing

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Marc Sole-Gras ◽  
Ruitong Xiong ◽  
Changxiao Liang ◽  
William Roorda ◽  
Hitomi Yamaguchi ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Time Interval ◽  
Material System ◽  
Laser Printing ◽  
Optical Scanner ◽  
Material Deposition ◽  
Forward Transfer ◽  
Laser Frequencies ◽  
Deposition Processes ◽  
Viscous Solutions

Abstract Laser-induced forward transfer (LIFT) is a well-established, versatile additive manufacturing technology for orifice-free printing of highly viscous solutions and suspensions. In order to improve the efficiency of point-wise LIFT printing, an optical scanner is integrated into the laser printing system to enable the formation of overlapping adjacent jets used for deposition. The objective of this study is to evaluate the ejection behavior and deposition performance under such conditions during LIFT printing for further improvement. The effects of the overlap of adjacent jets are investigated in terms of jet formation and material deposition processes, capturing the jet tilting phenomenon caused by the perturbance induced by previously formed jet(s). The feasibility of optical scanner-assisted LIFT printing of viscous metal-based ink suspension has been successfully demonstrated during conductive line printing with induced overlapping jets. Investigation of various overlap ratios of adjacent jets found that a 30% jet overlap and a 133 µs time interval between laser pulses are optimal, in terms of deposition quality and ejection stability, even when a tilted jet ejection is present for the laser and material system in this study. Furthermore, multilayer polygonal and interdigitated structures are successfully deposited under these identified printing conditions. With the inclusion of an optical scanner, LIFT printing efficiency for viscous inks can be improved as the usage of higher laser frequencies is enabled, providing a faster orifice-free laser printing methodology.

scholarly journals Surface treatment on cobalt and titanium alloys using picosecond laser pulses in burst mode

2020 ◽  
Vol 127 (1) ◽  
Author(s):  
Daniel Metzner ◽  
Peter Lickschat ◽  
Steffen Weißmantel
Keyword(s):  
Surface Treatment ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Laser Source ◽  
Time Interval ◽  
Cobalt Chromium ◽  
Burst Mode ◽  
Self Organized ◽  
Implant Alloys ◽  
Cobalt Chromium Molybdenum

AbstractThe authors report on the results of surface treatment experiments using a solid-state amplified laser source emitting laser pulses with a pulse duration of 10 ps. The laser source allows the generation of pulse trains (bursts) with an intra-burst pulse repetition rate of 80 MHz (pulse-to-pulse time interval about 12.5 ns) with up to eight pulses per burst. In this study a wavelength of 1064 nm was used to investigate both ablation of material and laser-induced surface modifications occuring in metallic implant alloys CoCrMo (cobalt-chromium-molybdenum) and TiAlV (titanium-aluminum-vanadium) in dependence of the number of pulses and fluences per pulse in the burst. By using the burst mode, a smoothing effect occurs in a certain parameter range, resulting in very low surface roughness of the generated microstructures. It is demonstrated that at fluences per pulse which are smaller than the material-specific ablation threshold, a self-organized pore formation takes place if a defined number of pulses per burst is used. Thus, the advantage of the MHz burst mode in terms of a possible surface modification is established.

scholarly journals Overlapping Limitations for ps-Pulsed LIFT Printing of High Viscosity Metallic Pastes

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 168 ◽  
Author(s):  
David Munoz-Martin ◽  
Yu Chen ◽  
Miguel Morales ◽  
Carlos Molpeceres
Keyword(s):  
Laser Pulse ◽  
Short Distance ◽  
Laser Pulse Energy ◽  
Laser Pulses ◽  
High Viscosity ◽  
Single Step ◽  
High Speeds ◽  
Forward Transfer ◽  
Micron Size ◽  
Interference Problems

Laser-induced forward transfer (LIFT) technique has been used for printing a high viscosity (250 Pa·s) commercial silver paste with micron-size particles (1–4 µm). Volumetric pixels (voxels) transferred using single ps laser pulses are overlapped in order to obtain continuous metallic lines. However, interference problems between successive voxels is a major issue that must be solved before obtaining lines with good morphologies. The effects of the laser pulse energy, thickness of the donor paste film, and distance between successive voxels on the morphology of single voxels and lines are discussed. Due to the high viscosity of the paste, the void in the donor film after a printing event remains, and it negatively affects the physical transfer mechanism of the next laser pulses. When two laser pulses are fired at a short distance, there is no transfer at all. Only when the pulses are separated by a distance long enough to avoid interference but short enough to allow overlapping (≈100 µm), is it possible to print continuous lines in a single step. Finally, the knowledge obtained has allowed the printing of silver lines at high speeds (up to 60 m/s).

scholarly journals Blister-Actuated LIFT Printing for Multiparametric Functionalization of Paper-Like Biosensors

Micromachines ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 221 ◽  
Author(s):  
Lars Hecht ◽  
Korbinian Rager ◽  
Martynas Davidonis ◽  
Patricia Weber ◽  
Günter Gauglitz ◽  
...  
Keyword(s):  
Color Change ◽  
Laser Pulses ◽  
Active Components ◽  
Buffer Solution ◽  
Contact Printing ◽  
Micro Channels ◽  
Custom Made ◽  
Forward Transfer ◽  
Lateral Flow Test ◽  
Active Detection

Laser induced forward transfer (LIFT) is a flexible digital printing process for maskless, selective pattern transfer, which uses single laser pulses focused through a transparent carrier substrate onto a donor layer to eject a tiny volume of the donor material towards a receiver substrate. Here, we present an advanced method for the high-resolution micro printing of bio-active detection chemicals diluted in a viscous buffer solution by transferring droplets with precisely controllable volumes using blister-actuated LIFT (BA-LIFT). This variant of the LIFT process makes use of an intermediate polyimide layer partially ablated by the laser pulses. The expanding gaseous ablation products lead to blisters in the polyimide and ejection of droplets from the subjacent viscous solution layer. A relative movement of donor and receiver substrates for the transfer of partially overlapping pixels is realized with a custom-made positioning system. Using a specially developed donor ink containing bio-active components presented method allows to transfer droplets with well controllable volumes between 20 fL and 6 pL, which is far more precise than other methods like inkjet or contact printing. The usefulness of the process is demonstrated by locally functionalizing laser-structured nitrocellulose paper-like membranes to form a multiparametric lateral flow test. The recognition zones localized within parallel micro channels exhibit a well-defined and homogeneous color change free of coffee-ring patterns, which is of utmost importance for reliable optical readout in miniature multiparametric test systems.

Build strategies for rapid manufacturing of components of varying complexity

2015 ◽  
Vol 21 (3) ◽  
pp. 340-350 ◽  
Author(s):  
Suryakumar Simhambhatla ◽  
K.P. Karunakaran
Keyword(s):  
Manufacturing Process ◽  
Design Methodology ◽  
Layered Manufacturing ◽  
Rapid Manufacturing ◽  
Geometric Complexity ◽  
Content Type ◽  
Material Deposition ◽  
Fixed Axis ◽  
Deposition Processes ◽  
Deposition Direction

Purpose – This paper aims to develop build strategies for rapid manufacturing of components of varying complexity with the help of illustration. Design/methodology/approach – The build strategies are developed using a hybrid layered manufacturing (HLM) setup. HLM, an automatic layered manufacturing process for metallic objects, combines the best features of two well-known and economical processes, viz., arc weld-deposition and milling. Depending on the geometric complexity of the object, the deposition and/or finish machining may involve fixed (3-axis) or variable axis (5-axis) kinematics. Findings – Fixed axis (3-axis) kinematics is sufficient to produce components free of undercuts and overhanging features. Manufacture of components with undercuts can be categorized into three methods, viz., those that exploit the inherent overhanging ability, those that involve blinding of the undercuts in the material deposition stage and those that involve variable axis kinematics for aligning the overhang with the deposition direction. Research limitations/implications – Although developed using the HLM setup, these generic concepts can be used in a variety of metal deposition processes. Originality/value – This paper describes the methodology for realizing undercut features of varying complexity and also chalks out the procedure for their manufacture with the help of case studies for each approach.

Spiral-Like Path Planning Without Gap for Material Deposition Processes

2006 ◽  
Author(s):  
Kunnayut Eiamsa-ard ◽  
F. W. Liou ◽  
Lan Ren ◽  
H. Choset
Keyword(s):  
Path Planning ◽  
Cross Sections ◽  
Arbitrary Shape ◽  
Metal Deposition ◽  
Cnc Machining ◽  
Pocket Machining ◽  
Parallel Path ◽  
Material Deposition ◽  
New Strategy ◽  
Deposition Processes

Contour-parallel path, also called offset path, is a commonly used deposition strategy exploited by many deposition processes. This offset path has been studied vastly due to the potential of its applications. The majority of contour-parallel path research is found in robotics, CNC machining, and metal deposition. Even though curve offsetting has been extensively studied, there is virtually no algorithm that can produce a complete connected deposition path and can fill arbitrary shape cross sections entirely without gaps. This gap problem is similar to the uncut-region problem in CNC pocket machining. There are only few investigations on this uncut-region or gap problem even though the problem has long been recognized. A new strategy to divide regions and to plan the spiral-like deposition paths without gap based on contour-parallel paths is discussed in this paper. To prove the correctness and the usefulness of the proposed method, simulations and experiments are also discussed.

HARMONIC GENERATIONS OF CLUSTER Na2 IN ULTRASHORT INTENSE LASER PULSES

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2687-2692 ◽  
Author(s):  
F. S. ZHANG ◽  
F. WANG ◽  
Y. ABE
Keyword(s):  
Harmonic Generation ◽  
Local Density ◽  
Laser Pulses ◽  
Time Dependent ◽  
Intense Laser ◽  
Density Approximation ◽  
The Third ◽  
Intense Laser Pulses ◽  
Laser Frequencies ◽  
Ponderomotive Potential

In the framework of the time dependent local density approximation the harmonic generation of Na2 in ultrashort intense pulses is investigated. The coupling between harmonics and plasmons of Na 2 is discussed in detail with two laser frequencies 5.266 eV, which is double the resonance of the plasmon, and 1.124 eV, which is half the frequency of plasmons, and with two different peak intensities. One finds appearance of the third and the fifth harmonic generation at high ponderomotive potential.

scholarly journals Effects of Layer-Interface Properties on Mechanical Performance of Concrete Elements Produced by Extrusion-Based 3D-Printing

2018 ◽  
Author(s):  
Venkatesh Naidu Nerella ◽  
Simone Hempel ◽  
Viktor Mechtcherine
Keyword(s):  
Flexural Strength ◽  
Mechanical Performance ◽  
Time Interval ◽  
Self Healing ◽  
Layer Interface ◽  
Material Deposition ◽  
Macro Scale ◽  
3D Printed ◽  
Pozzolanic Additives ◽  
Concrete Elements

Interfaces between layers in 3D-printed elements produced by extrusion-based material deposition were investigated on both macro- and micro-scales. On the macro-scale, compression and bend tests were performed on two 3D-printable cement-based compositions (3PCs), namely C1 and C2. The influences of binder composition and time interval between layers on layer-interface strength were critically analyzed. In the context of additive manufacturing, the optimized composition C2, containing pozzolanic additives, exhibited mechanical performance superior to that of the mixture with Portland cement as the sole binder. In particular, Mixture C2 showed a less pronounced decrease in interface tensile strength. Even for time intervals between depositions of two layers as long as 1 day the loss in corresponding flexural strength was below 25%, as compared with C2 specimens tested in the perpendicular direction. In contrast, the decrease in flexural strength measured for C1 specimens amounted to over 90% for the same set of parameters. Higher porosity at the interfaces of the printed concrete layers was identified as the cause for the lower interface strengths of C1. Microscopic observations supported the findings of the macroscopic investigations. While a pronounced recovery (“self-healing”) of the porous, discontinuous interlayers was observed with increasing age for Mixture C2, in case of C1 the filling products grown in the porous interlayer were found to be non-strengthening.

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