Wallace Carr Publications

The objective of the proposed research is to develop fundamental understanding of the process of deposition of complex mixtures by the inkjet method. Motivation for this work results from the requirement that “inks” in a growing number of textile applications contain solid particles, typically also requiring additives including dispersants. Such inks are likely to be highly solids-laden and non-Newtonian, making prediction of behavior based on existing understanding of drop formation from Newtonian liquids unsatisfactory. The formulation of high performance / high value-added treatments in the form of inks for textiles greatly affects deposition and ink-substrate interaction. Characterization of the effects of the various components of the solids-laden inks on drop formation and substrate interaction is crucial to utilization. Based on a background in study of drop formation and impaction from mixtures, we propose to thoroughly characterize and model the phenomena associated with inkjet deposition to textiles. By the end of the third year we will: i) identify the effects of the solid-laden ink properties on drop formation in drop-on-demand (DOD) inkjet systems, ii) prescribe regions of reliable jetting behavior in DOD inkjet systems, iii) develop a model for prediction of the solid-laden ink properties on drop impaction and spread on rough and heterogeneous surfaces, including textile surfaces.

Novel, Hot-Air, Jet-Tube System for Drying/Curing Individual, High Speed Threadlines

The current methods for applying materials such as sizes, colorants and finishes on a rapidly moving threadline are incompatible with today’s mass-customization, short-run manufacturing strategies. A method for single-end application of materials for many textile operations would improve both the productivity and flexibility of wet processes. It would allow the industry to offer shorter “made to order” jobs to their customers, thus making them more competitive in the world market. In a previous CCACTI project, a single-end applicator for sizing yarn was developed and demonstrated in a plant test. The single-end sizing applicator was successfully used to apply size solution to a sheet of 94 yarns simultaneously, but a major problem with yarn breakage inside the microwave drying oven was encountered. Re-starting the system after single yarn breaks was also difficult. Since it became obvious that a single-end drying system that would isolate single yarns in the event of breaks would be necessary, the plant test was discontinued. Although the plant test was not a complete success, the industrial partners agreed that the single-end sizing applicator was promising and should be pursued, but a new method for drying the yarn must be developed for single-end sizing (or application of other chemicals or colorants to the moving thread line) to be successful. The objective of the proposed project is to develop a hot-air, jet-tube system for drying and/or curing individual threadlines moving at high speed. The accomplishment of this objective will allow utilization of the single-end applicator for applying a wide range of materials such as sizes, colorants and finishes on a rapidly moving threadline. Commercialization of the single-end sizing process should greatly improve productivity and flexibility that is needed to allow short-run, quick-response, capability necessary to meet today's global competition while providing a continuous processing alternative to batch application of chemicals/colorants to yarns, e.g., package and beam dyeing.

This study is expanding the scientific knowledge base for textile ink jet technology, which will enhance the competitiveness of the U.S. textile industry. The project is providing a foundation for rational design and advancement of the ink jet technology in textiles, with consequent economic benefits which are expected to include reduction of the time required to go from design to market. The research addresses the fundamental mechanisms of droplet formation and drop/surface interaction in the regimes characteristic of textile ink jet printing. Drop impaction on and interaction with surfaces of varying interfacial properties are being studied for drop size from micron diameter to the millimeter scale. We are conducting research to identify the role of particulates in drop formation and to prescribe regimes of reliable jetting behavior. We are investigating the effects of surface morphology (roughness) and surface energy on drop spreading dynamics in an effort to determine the critical parameters associated with textile surfaces that influence drop/surface interaction and subsequent image quality.

It is generally accepted that ink jet printing will become an important technology in printing of textiles, particularly in a demand-activated manufacturing environment. Ink jet printers have been used for producing samples in the design process and for small-scale production prints of exclusive design (e.g. ties and scarves), but printing speed must be increased and hardware reliability problems must be overcome for ink jet printing to be used in large-scale textile production. This research project is directed at improving ink jet printing of textiles. Existing ink jet systems exhibit significant problems in reliability (nozzle plugging, air injection, etc.), and ink/textile -media interactions are not well understood. The objectives of this project are: 1) To obtain fundamental understanding of the role of particles in setting the flow behavior and droplet formation characteristics in textile ink jet printing nozzles and 2) To understand at a fundamental level the interactions of a single ink-jet droplet with textile printing media on image formation.

The objective of this research is to understand and quantify moisture transport in textile structures so that novel/improved drying processes may be developed. Magnetic Resonance Imaging (MRI) techniques are being employed to measure one-, two-, and three-dimensional images of water within textile substrates. Because a single image can be measured in a matter of milliseconds, real-time monitoring of actual drying processes, as well as diffusion of moisture with in the textile, is possible. Mechanisms of drying are being established by following water distribution as a function of drying time. Through-air drying of wet nylon carpet is being simulated inside the MRI scanner. Based on the MRI results, a model of the through-air drying process will be constructed and verified using a laboratory though-air dryer which closely simulates the industrial drying process. The results will be used to propose new drying processes, such as combined IR and convective heating

This project is aimed at improving the productivity and flexibility of the weaving sector of the textile industry. The set up time for the current slashing system is long, requiring long process runs to obtain acceptable process efficiency. This mode of operation is incompatible with todayกฏs demand activated manufacturing strategies. A totally new method of slashing that is environmentally friendly and will greatly improve production speed and flexibility is needed. Single-end slashing earlier in the process would allow the industry to offer shorter กฐmade to orderกฑ jobs to their customers, thus making them more competitive in the world market. A process is being specifically designed for sizing yarns before or during the warping operation. This study involves investigating methods for applying size to a rapidly moving threadline and developing sizing materials that are compatible with the application technique while giving the required sized-yarn properties.

Moisture Sensors for Control and Optimization of Carpet Processes for Energy and Environmental Savings (with J. L. Dorrity)

Process moisture sensors are needed for control and optimization for many fabric and carpet processes. Overdrying and underdrying can lead to problems including reduction in quality, decreased productivity, increased environmental pollution and increased energy consumption. For example, controlling the moisture in the process of applying secondary backing to carpet is important. Not only does monitoring the moisture in the backing process have the potential of improving the quality of the product, but also, by using the output to control various components of the line, the overall energy efficiency of the range can be vastly improved. The accuracy and reliability of most of commercially available sensors are too low for application in many manufacturing processes. This project involves developing and demonstrating moisture sensors most suitable for use in control systems for carpet manufacturing processes.

A Model to Evaluation the Effectiveness of Carpet and Floor Coverings in Reducing Energy

Wallace Carr

Research Abstracts - Wallace Carr