A novel operation mode for piezo inkjet printheads has been invented to close the gap of current commercial printheads in meeting the requirements for advanced additive manufacturing. Subsequently, a printhead using the new technology has been developed along with the necessary sub-systems for integration in a printer. The new inkjet technology brings a combination of advantages, the most relevant being the capability to jet extremely high viscosity fluids, combined with very high productivity per nozzle, very wide drop size control and the capability to jet fluids with high particle load and large particle sizes.

On-Demand Electro Spraying or Single Event Electrospraying (SEE) is a method to jet small amounts of fluid out of a nozzle with a relatively large diameter by switching on and off an electrical field between nozzle and substrate. The jet decomposes in many fl droplets, the total amount of volume deposited is up to 5 pl. A pipette is considered in which an electrode is mounted close to the exit of the nozzle. The electrode is connected to a high voltage power amplifier. By switching on the electrical field the apparent surface tension drops, the meniscus deforms into a cone and fluid starts to flow towards the nozzles. The moment the cone has reached the Taylor cone dimensions, from the tip of the cone a jet emerges and a number of charged fl droplets fly towards the substrate. This process stops when the pulse is switched off. After switching off the meniscus returns slowly to its equilibrium position. The process is controlled by different time constants, such as the slew rate of the power amplifier and the RC time of the electrical circuit composed of the electrical resistance in the fluid contained in the nozzle between electrode and meniscus, and the capacitance of the gap between the meniscus and the flat substrate. Another time constant deals with the fluid flow during the growth of the meniscus, directly after switching on the pulse. This fluid flow is driven by hydrostatic pressure and opposed by viscous drag in the nozzle. The final fluid flow during droplet formation is governed by the balance between by the drag of the charge carriers inside the fluid, caused by the current associated with the charged droplets leaving the meniscus and the viscous drag. These different phenomena will be discussed theoretically and compared to experimental results.

We proposed the method for non-destructively embedding information inside a 3D fabricated object very clearly by the process of re-magnetization. Our strong points are that the 3D object is finished (ready to use) after only a printing process, and is able to be reused by re-writing information many times. In this paper, we investigated the effects of the depth (positions inside the object) of the storage cell, which is printed as a ferromagnetic filament, on the clarity of the embedded information. Our purpose: we need to find the conditions that gave the most benefit in both obtaining high magnetic strength and protecting the embedded information. With this advantage, the method leads to the production of creating the high-quality household 4D object, the personal interactive 3D object, in the near future.

This paper provides examples of the use of direct print additive manufacturing to fabricate RF/microwave and optical components. Direct print additive manufacturing is the combination of extrusion and micro-dispensing on a single tool. The design, 3D printing process and material selections for finite ground coplanar waveguide (FG-CPW) planar transmission lines, the integration of DC contact RF MEMS switches within the FG-CPWs, and optical interconnects are detailed. Picosecondpulsed laser machining is performed to enhance the finish quality of the devices and achieve minimum feature size down to 6 μm specifically for the RF switch.

The invention of photography in the 19 th century changed our perception of reality for ever. Without the interpretation of an artist, an image could be recorded within minutes representing 'unfiltered' reality. Besides the scientific challenge how to capture the light and make the image permanent, the distribution of the image material became a scientific and commercial endeavor at the same time. We will present modern reincarnations of two technologies practiced by Walter Woodbury, the inventor of the first commercially successful photomechanical reproduction method: Merging Wet-Collodion photography and Woodburytype.

Digital and analogue printing methods are studied for reconstructing a Mayan decorative relief from the ancient temple of the Jaguars. Height maps, image files encoding height information as intensity values, were produced in commercial image editing software from early 20th century photographic records. Physical height was generated in different materials through analogue printing processes including casting and embossing from photo exposed polymer plates, and digital processes including 2.5D elevated printing and stereolithography. The surface geometry of the outcomes from the analogue processes was recorded using photometric stereo to obtain feedback on the translation of the grayscale range onto relief. 2.5D prints produced with Canon Elevated Printing and stereolithography were used for comparison and qualitive assessment. Differences, parallels and sustainability of the processes are discussed.

Digital textile printing technology has been considered the preferred textile printing technology since 2003, when production digital textile printers were first introduced at ITMA (International Exhibition of Textile Machinery) in Birmingham, UK. However, in 2021, 18 years later, this technology is utilized in fewer than 10% of the entire textile printing industry. In this document, we aim to summarize the state-of-the-art of the digital textile printing industry and to predict its future trajectory.

This research explored the potential for ink-jet printing to replicate the coloration and finishing techniques of traditional denim fabric and standardized the reproduction and evaluation procedure. Although denim fabric is widely consumed and very popular, one drawback to denim is that the finishing and manufacturing processes are energy and water intensive and can cause environmental hazards as well as generation of pollution through water waste, particularly at the finishing stage. Textile ink-jet printing has the potential to replicate some of the coloration and finishing techniques of traditional denim fabric without negative environmental impacts. A two-phase research project was conducted. In Phase I (P1), an optimal standard production workflow for digital denim reproduction (including color and finishing effects) was established, and six different denim samples were reproduced based on the workflow. In Phase II, an expert visual assessment protocol was developed to evaluate the acceptance of the replicated digital denim. Twelve ink-jet printing, color science, and denim industry experts finished the assessment.

In this paper, a method for the simultaneous provision of material validation, mass serialization, and binding enhancement using a portable hardness tester is presented for 3D printed parts. The process described in this paper is intended for implementation using a robotic arm-mounted hardness tester for ease of integration into a manufacturing environment, and adaptability of the process for custom parts. Hardness testing can be used for material validation, but the process of hardness testing leaves an indent in the material where the test is performed. Thus, the indents must be placed where they do not affect desired aesthetics, or else coupled with another desired process. By administering the hardness tests in a specified pattern on the material, the indents created on the material can be used for two additional functions – increasing the surface area to enhance joining, and marking an item-specific serialization code on the part that can be used for later identification. The postprocessing of 3D printed parts can be streamlined by completing these three objectives in a single process that is highly adaptable to customized manufactured parts through an implementation using a robotic arm.