Cross Machine Direction Research Articles

Effect of doctoring on the performance of direct gravure printing for conductive microfine lines

Printed electronics on flexible thin film has challenged and inspired the motivation of scientists in many fields. Among traditional printing methods such as stamping, flexography, offset, screen-printing, and inkjet, the gravure method is expected to reduce costs and increase productivity for printed electronics applications. In this research, conductive microfine line patterns, which print out the layer as microelectrodes for organic thin film transistor (OTFT) or microcircuit lines, have been designed with different size widths and lengths according to the printing direction, MD (machine direction), and CMD (cross machine direction, or transverse direction, TD, which is popularly used in industry). These patterns were printed with nano-particle silver ink on PI thin film, but had some serious problems with discontinuity and less filling after doctoring and printing. To solve these problems, the doctoring effect is investigated and analyzed before ink transferring, mainly in the printing machine direction and CMD. The uniformity and accuracy of the microfine lines are controlled and improved in order to achieve the stability of the printed pattern lines. In this work, considering the effect of the deflection of the doctor blade in the CMD (transverse direction), a doctoring model in the CMD is proposed and compared with the experimental result. Experimentally, proper doctoring conditions like blade stiffness and doctoring pressure are sought.

Optimization of Production Parameters of Geotextiles Used for Shoreline Protection

The use of geotextile sand containers (GSCs) in shoreline protection systems has moderately grown since the first applications in the 1970s and increasingly used as an alternative to natural stone, slag, and concrete. Due to their economical, technical and ecological advantages, the use of geotextiles and geocomposites for filter and drainage functions is increasing worldwide and has a 40 year history already. For coastal protection measures, nonwovens are proven to have long-term resistance against ultraviolet radiation and saltwater. High elongation behavior provides superior properties during loading in coastal protection means, which is determined as being the biggest risk for damaging geotextiles. Such applications require certain functional characteristics in the geotextiles, besides their basic properties, which are required to be engineered by the judicious optimization of the needlepunching process. In this study, the effect of the process parameters including punch density and depth of needle penetration has been investigated on the mechanical (tensile strengths in the machine and cross-machine directions) properties of needlepunched nonwoven geotextiles. These process parameters are then empirically related to the fabric properties by using a multiple regression technique.

Development of hydroentangled nonwoven fabrics for the protective garments

The aim of this research was to establish the optimum processing conditions for producing hydroentangled nonwoven fabrics best suited for application in disposable and protective wear, such as surgical gowns, drapes and laboratory coats. Carded and cross-lapped webs, from greige cotton, viscose and polyester fibres of three basic weights, were hydroentangled, at three different waterjet pressures on a Fleissner’s Aquajet hydroentanglement machine. An antibacterial agent and a fluorochemical water repellent finish were applied in one bath using the pad-dry-cure technique to impart both antibacterial and water repellent properties to the fabrics. The standard spray ratings, tensile strength and extension at break for three treated and untreated fabrics were evaluated. The spray ratings for the treated fabrics ranged from 80% to 90% against zero for the untreated fabrics while the tensile strengths in both the machine and cross-machine directions of treated fabrics were greater than that for the untreated fabrics, the reverse being true for the extension at break. Contact angles for all treated fabrics exceeded 90° which indicate good resistance to wetting. The finishing treatment decreased the mean pore size of all fabrics and increase in waterjet pressure and fabric weight decreased the air and water permeability. In this study, it was observed that low weight fabrics of 80 g/m2 hydroentangled at low waterjet pressure of 60 bars were suitable for use due to their higher air and water vapour permeability as well as higher pore size distribution. These fabrics meet the requirements for surgical gowns, drapes, nurses’ uniforms and laboratory coats.

Comparison of Wood Composite Properties Using Cantilever-Beam Bending

Wood-based composite panels generally are first tested out-of-plane in the primary panel direction followed by the cross panel direction, but rarely edgewise. While most applications use wood-based composites in the flat-wise orientation and only need the out-of-plane properties, there are construction configurations where edgewise properties are needed for improved design configurations. A square cantilever beam was used to determine the apparent stiffness (EI) and modulus of elasticity (E) differences for 3 wood-based composite panel materials. Specimens were cut along the primary panel direction or machine direction (MD) and perpendicular to the primary direction or cross-machine direction (CD). The square specimens were first non-destructively tested oriented in the normal or out-of-plane position, then rotated 90 degrees to measure edgewise properties. The results for a 20 mm thick medium density fiberboard (MDF) showed that the MD properties were 56% higher than the CD properties. The other two composite materials, 12 mm thick particleboard (PB) and 12 mm thick MDF, were essentially the same in the MD or CD directions. For all the materials, the differences between the out-of-plane and the edgewise loading directions showed higher EI and E between 17 to 61%, respectively. The largest difference was found in the PB composite material properties that were between 42 to 61% higher for the out-of-plane properties. For the 12 and 20 mm thick MDF material, in-plane properties were 27 to 33% and 17 to 23% higher, respectively. The cantilever bending method was able to quickly assess the difference using the same specimen.

Measurement of Fiber Board Poisson's Ratio using High-Speed Digital Camera

Purpose: The finite element method (FEM) is advantageous because it can save time and cost by reducing the number of samples and experiments in the effort to identify design factors. In computational problem-solving it is necessary that the exact material properties are input for achieving a reliable analysis. However, in the case of fiber boards, it is difficult to measure their cross-directional material properties because of their small thickness. In previous research studies, the Poisson's ratio was measured by analyzing ultrasonic wave velocities. Recently, the Poisson's ratio was measured using a high-speed digital camera. In this study, we measured the transverse strain of a fiber board and calculated its Poisson's ratio using a high-speed digital camera in order to apply these estimates to a FEM analysis of a fiber board, a corrugated board, and a corrugated box. Methods: Three different fiber board samples were used in a uniaxial tensile test. The longitudinal strain was measured using the Universal Testing Machine. The transverse strain was measured using an image processing method. To calculate the transverse strain, we acquired images of the fiber board before the test onset and before the fracture occurred. Acquired images were processed using the image processing program MATLAB. After the images were converted from color to binary, we calculated the width of the fiber board. Results: The calculated Poisson's ratio ranged between 0.2968-0.4425 (Machine direction, MD) and 0.1619-0.1751 (Cross machine direction, CD). Conclusions: This study demonstrates that measurement of the transverse properties of a fiber board is possible using image processing methods. Correspondingly, these processing methods could be used to measure material properties that are difficult to measure using conventional measuring methodologies that employ strain gauge extensometers.

Effects of blown film process on initial properties of HPDE geomembranes of different thicknesses

ABSTRACT: The differences in the properties of five high density polyethylene geomembranes (GMBs) of different thicknesses made by the same manufacturer from same GMB resin are investigated. The 1.0, 1.5, 2.0 and 2.4 mm thick GMBs investigated were manufactured during the same production run by changing the pulling speed of the GMB out of the extrusion die, such that, the pulling speed decreased with increasing thickness. There were no differences in the initial HP-OIT or Std-OIT values of the different GMBs. However, there were differences in the key mechanical and physical properties of the GMBs that cannot be simply explained by the increase in the amount of material due to increasing GMB thickness. These differences are explained by differences in the morphological structure of the GMBs arising from the different thermal and stress histories experienced during the manufacturing process. The effects of the differences in the morphological structure are discussed in terms of: the decrease in the relative differences between the stress–elongation curves in the machine and cross-machine directions as thickness increases; changes in the enthalpies of melting and crystallisation by differential scanning calorimetry with changing thickness; and the different stress crack resistance (SCR) for the GMBs. For example, thinner GMBs had a greater difference between the SCR in the machine and cross-machine direction. Increasing the GMB thickness from 1.5 to 2.4 mm resulted in increasing the SCR from ∼ 800 to ∼ 1100 h in the cross-machine direction and decreasing its SCR from ∼ 4100 to ∼ 2000 h in the machine direction. Thus, GMBs of different thickness manufactured from the same resin can be expected to have differences in their physical and mechanical properties that are dependent on the additional material but also the difference in the tension and cooling rate experienced during the manufacturing process.

MECHANICAL PROPERTIES OF FLEXOGRAPHIC PRINTS / FLEKSOGRAFINIŲ ATSPAUDŲ MECHANINĖS SAVYBĖS

Mechanical properties of paper and flexographic prints madewith different anilox rollers were investigated experimentally.Flexographic prints roughness, breaking force and folding resistancevalues were determined. The results showed that foldingresistance is bigger for machine direction prints than for crossmachine direction prints. Flexographic prints on cardboardsfolding resistance values are different for machine direction andcross machine direction. It was determined that roughness offlexographic prints increases with the amount of ink on aniloxroller. Results were explained by the ink water influence. Santrauka Eksperimentiškai ištirtos įvairių rūšių popieriaus ir fleksografinių atspaudų, gautų dengiant popierių skirtingo plotinio tūrio aniloksiniais voleliais, mechaninės savybės. Nustatytos popieriaus ir fleksografinių atspaudų šiurkštumo, atsparumo tempimui bei atsparumo lenkimui vertės. Gauti rezultatai parodė, kad atspaudų atsparumas lankstymui yra didesnis išilgine nei skersine popieriaus kryptimi. Dengiant kartonus fleksografiniais dažais, atsparumas tempimui keičiasi, ir ši kaita yra skirtinga išilgine ir skersine kryptimis. Nustatyta, kad fleksografinio atspaudo šiurkštumas didėja, storėjant dažų sluoksniui ant aniloksinio volelio. Manoma, kad taip nutinka dėl dažuose esančio vandens.

Quasi static analysis of creasing and folding for three paperboards

The creasing and folding behavior of three paperboards have been studied both experimentally and numerically. Creasing and folding studies were performed on strips in both the machine direction and the cross machine direction. A finite element model that mimicked the experimental creasing and folding setup was developed, and the creasing and folding behavior could be well predicted for all three paperboards.An experimental characterization scheme consisting of three experiments was proposed, and was shown to be sufficient to predict the creasing and folding behavior. For the whole paperboard the shear strength profiles in the through thickness direction was determined with the notched shear test. Each ply was laid free by grinding, and density measurements and in-plane tension tests were performed on the bottom, middle and top plies of each paperboard. Instead of assuming uniform properties in each ply, the shear strength profiles were used to map the measured properties in the through thickness direction.Numerical simulations were performed when the ply and interface properties of the paperboards were altered to follow different shear strength profiles. This was done in order to mimic different production strategies. It was shown that the interface strengths mainly influenced the folding behavior. Whereas altered the ply properties affected the creasing force needed.

Tailoring the structure and properties of jute blended nonwoven geotextiles via alkali treatment of jute fibers

Geotextiles are generally made from natural or synthetic fibers and both fibers offer their own advantages and disadvantages for geotechnical applications. In this study, the jute fibers were treated with 4wt.% sodium hydroxide (NaOH) solution in order to enhance their tensile properties. A series of needlepunched nonwoven geotextiles were then fabricated by formulating blends of untreated jute and polypropylene fibers and corresponding sets of nonwovens containing alkali treated jute and polypropylene fibers in defined weight proportions. Subsequently, a comparison has been made between the physical and mechanical properties of these blended nonwoven geotextiles. In general, the alkali treated jute blended nonwoven geotextiles offer higher puncture resistance in addition to higher tensile and tearing strengths in the cross-machine (preferential) direction than their corresponding blended geotextiles consisting of untreated jute fibers. Blended nonwoven geotextiles consisting of more than 40wt.% jute fibers were not found to be useful in enhancing the mechanical properties.

Influence of In-Isolation Properties of Geogrids on Their Pullout Performance in a Dense Graded Aggregate

A series of in-isolation and pullout tests was carried out on selected extruded (EGG) and non-extruded (NEGG) geogrid products that are available for base reinforcement and subgrade stabilization applications. The objective of the study was to examine the influence of selected geogrids index properties on their in-aggregate performance in roadway applications. The pullout tests were carried out in Oklahoma Department of Transportation (ODOT) Type-A aggregate, which is a dense-graded aggregate most commonly used in ODOT projects. Pullout tests provide useful information on the in-aggregate performance of geogrids outside the stress bulb directly beneath the tire pressure. The in-isolation properties studied included the geogrids low-strain (i.e. 2 and 5 % strain) rib strength, and ultimate rib strength and junction strength in both machine and cross-machine directions. Results of the study indicated that for both EGG and NEGG categories of geogrids examined, greater rib and junction strength properties overall resulted in greater pullout resistance. Geogrids junction strength and low-strain rib strength showed a reasonably strong correlation with their pullout performance regardless of the geogrid category examined. The rib strength at 2 % strain showed a stronger correlation than the 5 %-strain strength with the geogrid pullout performance. However, ultimate rib strength of geogrid showed convincing correlations with their pullout performance only when they were examined in separate categories with respect to their manufacturing technique (i.e. when the EGG and NEGG geogrids were examined as separate categories). The findings of this study are expected to be beneficial in relating the in-isolation properties of geogrids to their in-aggregate performance.

Mechanical properties and damage analysis of jute/polypropylene hybrid nonwoven geotextiles

Hybrid needlepunched nonwoven geotextiles are prepared in defined weight proportions of jute and polypropylene fibres. Subsequently, a comparison is made between various physical and mechanical properties of hybrid needlepunched nonwoven geotextiles. It was found that 40 wt.% jute was an optimum level in hybrid nonwoven geotextiles that had a comparable tensile strength and higher secant modulus specifically in the cross-machine (preferential) direction in comparison to 100% polypropylene based nonwoven geotextiles. Two types of mechanical damage (i.e., a horizontal cut and a circular hole) were artificially induced in the hybrid nonwoven geotextiles and their notch-sensitive behaviour and the failure mechanisms are reported.

Damage analysis and notch sensitivity of hybrid needlepunched nonwoven materials

Needlepunched nonwovens are complex three-dimensional (3D) entangled fibrous materials which are extensively used for a range of technical and industrial applications. The micromechanisms of deformation and fracture behavior of these materials are complicated and least understood. In this study, the tensile behavior of virgin and notched samples is investigated for hybrid needlepunched nonwoven materials consisting of polypropylene and viscose fibers in defined proportions. The notches in nonwovens were induced by two types of mechanical damage (circular hole and vertical cut) in three spatial positions of hybrid nonwovens tested in the machine, 45°, and cross-machine directions. The notch sensitivity of hybrid nonwovens was demonstrated by localized fiber failures occurring around the region of induced damages. It was established that the shape and spatial position of induced damage have significant influence on the tensile behavior of hybrid nonwoven materials. Higher viscose contents (60–80 wt%) in notched hybrid nonwovens yielded minimal tensile strength reduction specifically in the preferential (cross-machine) direction.

Real Time Surface Measurement Technique in a Wide Range of Wavelengths Spectrum

Real time surface topography measurement in the paper and paperboard industries is a challenging research field. The existing online techniques measure only a small area of paper surface and estimate topographical irregularities in a narrow scale as a single predictor. Considering the limitations and complications in measuring the surface at high speed, a laser line triangulation technique is explored to measure surface topography in a wide scale. The developed technique is new for the paper and paperboard application that scans a line onto the paper-web surface up to 210 mm in length in the cross machine direction. The combination of a narrow laser linewidth imaging, a subpixel resolution, and the selection of a unique measurement location has made it possible to measure roughness and simultaneously characterize paper surface topography from 0.1 to 30 mm spatial wavelength. This spatial range covers wide scale surface properties such as roughness, cockling, and waviness. The technique clearly distinguishes and characterizes the surface of newspaper, and lightweight coated, coated, and uncoated paperboard in real time during the paper manufacturing process. The system temporal noise for the average roughness is estimated as 37 dB. The signal to noise ratio found is from 5.4 to 8.1 in the short spatial wavelength up to 1 mm, whereas it is more than 75 in the long spatial wavelength from 5 to 10 mm.

Design Optimization of Nonwoven Processing Parameters Using Hybrid Taguchi and TOPSIS Approach

This study aimed to apply Taguchi method and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to optimize multiple qualities of needlepunched nonwoven fabrics with the fewest experiments. The quality characteristics are tear strength of machine direction (MD)/ cross machine direction (TD) and tensile strength of MD/TD. From nine experiments based on the L9 orthogonal array, the swing rate of the cross-lapper machine is 1500 rpm, the delivery rate of the cross-lapper machine is 15 cm/min, the depth of the needle penetration is 14 mm, and the punch density is 60 punches/cm2 were found to be the optimal processing parameters. Finally, ten confirmation experiments were executed to ensure the reliability and reproducibility of the TOPSIS predicted optimal conditions with a 95% confidence interval for the needlepunched nonwoven fabrics.

Manufacturing Techniques and Mechanical Properties of Recycle Kevlar®/PET Composite Nonwoven

Kevlar® fiber has characteristics of thermostability, high modulus, low elongation, impact resistance, chemical resistance and high performance. Therefore, in this study Kevlar® fiber was used to reinforce the nonwoven fabrics. In this research, the content of the Kevlar® fiber was varied as 0 wt%, 5 wt%, 10 wt%, 20 wt%, and that of 15D PET fiber was changed as 70 wt%, 65 wt%, 60 wt%, 50 wt% accordingly when the Low-Tm polyester fibers was constant as 30 wt%. These fibers were used to manufacture the Kevlar®/PET composite nonwoven by nonwoven processing. Afterwards, the mechanical properties of the Kevlar®/PET composite nonwoven was measured both at cross direction and machine direction.

Manufacturing Techniques and Mechanical Properties of Recycle High-Strength PET Compound Nonwoven

The high-strength polyester fiber is a kind of chemical fiber that is rapidly developed and widely applied. With development of technology, the demands for polyester fiber are becoming more and more. Furthermore, the high-strength polyester fiber, used to reinforce the matrix, has higher modulus and strength than commercial polyester fiber. In this research, the 15D polyester fiber, the low melting polyester and the high-strength polyester fiber were used to manufacture the high-strength PET compound nonwoven fabrics by nonwoven processing. Afterwards, the mechanical properties of the PET compound nonwoven was measured both at cross direction and machine direction.

The effect of roller taper on webs

Webs moving through process machinery encounter several rollers, each of which might have unintentional taper in radius. The taper might have resulted from machining or from wear. The objectives of this study were to show, for a particular web, the level of cross machine direction registration error that might result for a given roller taper, the level of taper that will induce web trough instability in free spans, and the level of taper that will induce web wrinkle instabilities on rollers.

Humidity effect on compressive deformation and failure of recycled and virgin layered corrugated paperboard structures

This paper evaluates the humidity effect on the elastic properties and failure mechanism of two types of layered corrugated paperboard structures composed of entirely recycled material and virgin radiata pine (Pinus radiata D. Don) kraft and mixed fibre linerboards and fluting medium. Board samples and their component paper sheets were tested at 50% and 90% constant relative humidity (RH) under compression load and images of failure zones were obtained by serial sectioning and confocal microscopy. The compressive strength and modulus of elasticity of all components were found to be highest in the machine direction at 50% RH and lowest in the cross-machine direction at 90% RH. Virgin paper sheet components performed better in compressive performance than recycled components in both directions and at both relative humidities. In both types of corrugated board microscopic examination showed that failure under compression at 50% and 90% RH occurred along the adhesive line as well as by failure of inter-fibre bonds within the components. The combination of failure mechanisms resulted in local buckling of the boards. The elastic performance of recycled corrugated board was found to be inferior to that of virgin corrugated board at both RH conditions.

Assessment of the properties of poly(L-lactic acid) sheets produced with differing amounts of postconsumer recycled poly(L-lactic acid)

The properties of sheet containing mechanically recycled postconsumer poly(L-lactic acid) bottle flakes blended with virgin poly(L-lactic acid) resin were assessed. Poly(L-lactic acid) bottles were flaked, cleaned, blended with virgin resin and then extruded and thermoformed into trays. The molecular weight, physical, optical, thermal and mechanical properties of the sheet containing 0, 20, 40, 60, 80 and 100 wt.% poly(L-lactic acid) recycled content were evaluated. The best cleaning conditions were found by using a mixed-level fractional factorial design. Cleaning conditions of 15 min, at 85°C, 1 wt.% NaOH and 0.3 wt.% surfactant were adopted for cleaning the poly(L-lactic acid) flakes. Cast-extruded virgin poly(L-lactic acid) sheet had superior mechanical and optical properties than recycled poly(L-lactic acid) sheet. Recycled poly(L-lactic acid) sheets were darker and absorbed more ultraviolet light in the 260 to 285 nm range when 20% or more recycled content was added. At 40% poly(L-lactic acid) recycled content, the sheet had increased blue and red tones and the mechanical properties in the cross-machine direction decreased. At 60% poly(L-lactic acid) recycled content or above, reduction of weight average molecular weight, tensile strength and tensile strength at yield in the machine direction were found. At 80% poly(L-lactic acid) recycled content, the melting temperature and modulus of elasticity in the machine direction decreased. All sheet samples were successfully thermoformed into trays showing the potential to use post-consumer poly(L-lactic acid) flakes in the production of poly(L-lactic acid) containers.

Manufacturing Technique and Physical Properties of Environment-Protective Composite Nonwoven Fabrics

Rapid technical advancement threatens the earth ecology, driving people by degrees to develop green energy and green products. Tencel® fiber uses natural fibers. Products made of Tencel® fiber could be biodegraded, which solves the problems for the increasing consumptions of disposable nonwoven product. In this research, Tencel® fiber, polylactic acid (PLA) fiber, and high absorbent fiber (HAF) were used to produce Tencel®/PLA/HAF composite nonwoven fabrics. Among the nonwoven processing parameters, to increase the Tencel® fiber content helped heighten the water absorbency. When there were 80 wt% Tencel® fibers, the basis weight was 100 g/m2 and the needle-punching density was 300 needle/cm2, the Tencel®/PLA/HAF composite nonwoven fabric exhibited the optimum water absorbency in cross machine direction (CD), which was 5.0 cm. The air permeability of the Tencel®/PLA/HAF composite nonwoven fabrics reached 164.4 cm3/cm2/s when the basis weight was 100 g/m2 and the needle-punching density was 300 needle/cm2