Abstract Many ceramic manufacturing companies use three-dimensional (3D) computer-aided design (CAD) software and 3D printing technologies to produce design concept models for evaluation. Although the value to the design process is limited due to the types of material that can be printed, conventional modeling and processing methods still need to be used to achieve a design concept model in a real material. A solution is desired that delivers a prototype that looks and feels like the final product and which can be fully tested for functionality, glaze, and decoration. In collaboration with Denby Pottery as the industrial partner, this research project has refined and enhanced the 3D ceramic printing process already developed at the University of the West of England, and has enabled the production of concept models of new design ideas in a real ceramic material, printed directly from CAD data, fired, glazed, and decorated.

Abstract Rules for geometric design and compensation aim to guarantee that layout representations match final printed patterns within an accepted tolerance for a desired process yield. The more conservative the rules, the better the yield. Therefore, for a given process and after an experimental extraction of the required process parameters, it is possible to derive minimum design rules that characterize the technological process to a point where, without necessarily having an in-depth knowledge of the process and materials involved; design engineers can address physical design in order to develop devices and systems. In this article, a methodology for the extraction and characterization of inkjet geometric design rules and the application of compensation techniques to permit the inkjet manufacturing of reliable and precise designs is proposed as a first step towards separating design from digital fabrication, in a similar way to what has already occurred in silicon microelectronics technology.

Abstract Recent results from a number of UK academic inkjet research studies advance the understanding of complex fluid jetting behavior and may be of interest to the wider digital fabrication community for the enhancement of inkjet printing applications.

Abstract Laser-induced forward transfer, or LIFT, is a direct-write technique that enables nozzle-free, non-contact printing of 3-dimensional pixels or voxels of suspensions of functional materials across a wide range of viscosities with micrometer resolution. Printing of low-viscosity (<0.1 Pa s) nanoparticle (NP) inks by LIFT is in many ways similar to inkjet printing, where the cured voxel size and shape are determined by its interaction with the substrate. LIFT is also compatible with NP pastes of very high viscosity (>100 Pa s) and high solids content (>80 wt%), resulting in printed voxels that precisely replicate the shape and size of the laser transferring pulse. This LIFT regime, known as laser decal transfer or LDT, allows the congruent printing of highly loaded colloids and suspensions, unlike any existing direct-write process. This work compares LIFT of low-viscosity NP inks with LDT of high-viscosity NP pastes in terms of the voxels of silver NP suspensions printed by each technique. It also presents advances in a new digital fabrication technique using a spatial light modulator to change the size and shape of the LDT laser pulse, resulting in the dynamic reconfiguration of individual voxels. This enables a new level of parallelization unlike current serial direct-write processes, since each voxel can be varied according to the pattern design. An overview of the opportunities and challenges associated with LIFT of NP suspensions forms part of the conclusions.

Abstract In a color reproduction workflow, spectral prediction models are useful for establishing the correspondence between colorant surface coverages and resulting printed halftone color. Spectral prediction models enable calculation of the color gamut and establishment of the color separation tables. Discrete line juxtaposed halftoning, a recently proposed algorithm, is characterized by the fact that colorants formed by inks and ink superpositions are placed side by side. Juxtaposed halftoning is necessary when printing with special inks such as opaque or metallic inks. In order to predict the color of classical halftones, the Yule‐Nielsen modified spectral Neugebauer model is generally used. However, this model may not predict the color of juxtaposed halftones, since the effective surface coverages of colorants and of possible colorant overlaps are unknown. In contrast, the two-by-two dot centering spectral prediction model developed by S. G. Wang enables the reflectance of slightly overlapping colorants to be captured and is therefore appropriate for predicting the color of juxtaposed halftones. Since this model requires a large calibration set, the authors use an estimation technique which predicts more than 90% of the two-by-two calibration pattern reflectances by measuring less than 10% of them. For juxtaposed halftoning, the two-by-two dot centering model offers high prediction accuracies and outperforms the different variants of the Yule‐Nielsen spectral Neugebauer model for comparable setups.

Abstract Electro-optical devices are used for military applications to detect, identify and track targets. Typically, video information is presented to an operator. With an increasing availability of such devices data volumes are becoming large, and the need for automated analysis is becoming more urgent. In a military setting, this typically involves detecting and identifying targets as early as possible, i.e., when little visual information is available. The identification can be facilitated by combining the video stream into single enhanced images that provide more information for the operator. Using simulated and basic experimental images the authors study alignment in the aforementioned context and find that basic correlation is a potentially useful technique. Problems with background variation can be overcome and good alignment can be obtained even with severe noise. The authors illustrate how alignment quality responds to various parameters, which will help in the development of practical applications.

Abstract As more robust methods for ultra-violet (UV) curable inkjet printing are being introduced to market, alternative color and decorative printing methods have been tested for the art, design, and print sectors. In order to be able to increase the density of color, and improve the ink coverage when printing onto a range of non-standard substrates, this article describes results relating to the appearance of print on different surfaces, which includes both measured data (densitometry, gamut volume, International Colour Consortium (ICC) profiles) and a visual analysis (subjective assessment, microphotography). The objective is to address the requirements of the user, to accurately print a specific color through the multi-layering of inks, and to present methods of soft previewing the appearance of a multi-pass printed color. Several case studies are presented that incorporate recent research into the capabilities of UV curing technology, which has increased the opportunities for designers to print onto non-standard materials.