scholarly journals Correlation between Ink Thickness and "Shrink Sleeve" Flexographic Print Quality at a Stable Friction Coefficient

2021 ◽  
Vol 15 (3) ◽  
pp. 366-370
Author(s):  
Igor Zjakić ◽  
Ivana Ljevak ◽  
Albulena Bilalli
Keyword(s):  
Friction Coefficient ◽  
White Layer ◽  
Print Quality ◽  
Technology Usage ◽  
Flexographic Printing

Flexographic technology usage is increasing in recent years. Predicted growth in the technology usage intensifies the demand for improved quality. It is expected that flexographic printing will achieve greater results than ever before. Since this technique is used in the printing of shrink sleeve packaging, it is imperative to meet the technical and economic requirements of the shrink sleeve product. This is primarily to ensure gliding of the white printing material. The amount of white should be as small as possible, making the sliding of the material optimal and the quality of the print better. Therefore, the quality of the printing was measured by changing the conditions of slippage and white color. This research has established a correlation between the thickness of the white layer and the reduction of print quality over thin lines.

Flexographic ink-coating interactions: effects of latex variations in coating layers

TAPPI Journal ◽  
2016 ◽  
Vol 15 (4) ◽  
pp. 253-262 ◽  
Author(s):  
ERIK BOHLIN ◽  
CAISA JOHANNSON ◽  
MAGNUS LESTELIUS
Keyword(s):  
Contact Angles ◽  
High Ratio ◽  
Print Quality ◽  
Particle Sizes ◽  
Mixed Composition ◽  
Coating Surface ◽  
Covered Area ◽  
Surface Optical ◽  
Flexographic Printing ◽  
Coating Formulation

The effect of coating structure variations on flexographic print quality was studied using pilot-coated paperboard samples with different latex content and latex particle sizes. Two latexes, with particle sizes of 120 nm and 160 nm, were added at either 12 parts per hundred (pph) or 18 pph to the coating formulation. The samples were printed with full tone areas at print forces of 25 N and 50 N in a laboratory flexographic printing press using a waterbased ink. A high ratio of uncovered areas (UCAs) could be detected for the samples that contained 18 pph latex printed at a print force of 25 N. UCAs decreased with increased print force and with decreased amounts of latex in the coating formulation. The fraction of latex covered area on the coating surface was estimated to be 0.35–0.40 for the 12 pph, and 0.70–0.75 for the 18 pph samples. The ink penetration depth into the coating layer could be linked to the fraction of latex-free areas on the coating surface. Optical cross section microscopy indicated that a higher printing force did not increase the depth of penetrated ink to any greater extent. Higher printing force did increase contact between plate and substrate, leading to an improved distribution of the ink. This, in turn, increased print density and decreased UCAs. On closer inspection, the UCAs could be categorized as being induced by steep topographic changes. When appearing at other locations, they were more likely to be caused by poor wetting of the surface. To understand the wetting behavior of the coating surface, observed contact angles were compared with calculated contact angles on surfaces of mixed composition.

Influence of surface roughness, friction coefficient, and wrap angle on clinching joint strength and its correlation with belt friction phenomenon

2021 ◽  
pp. 135065012110253
Author(s):  
Santosh Kumar ◽  
Vimal Edachery ◽  
Swamybabu Velpula ◽  
Avinash Govindaraju ◽  
Sounak K. Choudhury ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Joint Strength ◽  
Joint Interface ◽  
Cross Sectional ◽  
Lap Shear ◽  
Mathematical Correlation ◽  
Mechanical Clinching ◽  
Wrap Angle

Clinching is an economical sheet joining technique that does not require any consumables. Besides, after its usage, the joints can be recycled without much difficulty, making clinching one of the most sustainable and eco-friendly manufacturing processes and a topic of high research potential. In this work, the influence of surface roughness on the load-bearing capacity (strength) of joints made by the mechanical clinching method in cross-tensile and lap-shear configuration is explored. Additionally, a correlating mathematical model is established between the joint strength and its surface parameters, namely, friction coefficient and wrap angle, based on the belt friction phenomenon. This correlation also explains the generally observed higher strength in lap-shear configuration compared to cross-tensile in clinching joints. From the mathematical correlation, through friction by increasing the average surface roughness, it is possible to increase the strength of the joint. The quality of the thus produced joint is analyzed by cross-sectional examination and comparison with simulation results. Experimentally, it is shown that an increment of >50% in the joint strength is achieved in lap-shear configuration by modifying the surface roughness and increasing the friction coefficient at the joint interface. Further, the same surface modification does not significantly affect the strength in cross-tensile configuration.

scholarly journals Face Grinding Surface Quality of High Volume Fraction SiCp/Al Composite Materials

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Xu Zhao ◽  
Yadong Gong ◽  
Guiqiang Liang ◽  
Ming Cai ◽  
Bing Han
Keyword(s):  
Friction Coefficient ◽  
Surface Morphology ◽  
Surface Quality ◽  
Volume Fraction ◽  
High Volume ◽  
Spindle Speed ◽  
High Volume Fraction ◽  
Machining Parameters ◽  
Al Composite

AbstractThe existing research on SiCp/Al composite machining mainly focuses on the machining parameters or surface morphology. However, the surface quality of SiCp/Al composites with a high volume fraction has not been extensively studied. In this study, 32 SiCp/Al specimens with a high volume fraction were prepared and their machining parameters measured. The surface quality of the specimens was then tested and the effect of the grinding parameters on the surface quality was analyzed. The grinding quality of the composite specimens was comprehensively analyzed taking the grinding force, friction coefficient, and roughness parameters as the evaluation standards. The best grinding parameters were obtained by analyzing the surface morphology. The results show that, a higher spindle speed should be chosen to obtain a better surface quality. The final surface quality is related to the friction coefficient, surface roughness, and fragmentation degree as well as the quantity and distribution of the defects. Lower feeding amount, lower grinding depth and appropriately higher spindle speed should be chosen to obtain better surface quality. Lower feeding amount, higher grinding depth and spindle speed should be chosen to balance grind efficiently and surface quality. This study proposes a systematic evaluation method, which can be used to guide the machining of SiCp/Al composites with a high volume fraction.

An improved nonlinear model considering relative velocity for the friction behavior between untwisted glass-fiber tow and roller

2021 ◽  
pp. 004051752110308
Author(s):  
Yang Liu ◽  
Zhong Xiang ◽  
Xiangqin Zhou ◽  
Zhenyu Wu ◽  
Xudong Hu
Keyword(s):  
Friction Coefficient ◽  
Glass Fiber ◽  
Relative Velocity ◽  
Friction Model ◽  
Woven Fabric ◽  
Test Results ◽  
Application Process ◽  
Friction Behavior ◽  
Improved Model

Friction between the tow and tool surface normally happens during the tow production, fabric weaving, and application process and has an important influence on the quality of the woven fabric. Based on this fact, this paper studied the influence of tension and relative velocity on the three kinds of untwisted-glass-fiber tow-on-roller friction with a Capstan-based test setup. Furthermore, an improved nonlinear friction model taking both tension and velocity into account was proposed. According to statistical test results, firstly, the friction coefficient was found to be positively correlated with tension and relative velocity. Secondly, tension and velocity were complementary on the tow-on-roller friction behavior, with neither being superior to the other. Thirdly, an improved model was found to present well the nonlinear characteristics between friction coefficient and tension and velocity, and predicational results of the model were found to agree well with the observations from Capstan tests.

scholarly journals A Comprehensive Investigation on 3D Printing of Polyamide 11 and Thermoplastic Polyurethane via Multi Jet Fusion

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2139
Author(s):  
Wei Shian Tey ◽  
Chao Cai ◽  
Kun Zhou
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Wear Rate ◽  
Mechanical Performance ◽  
Thermoplastic Polyurethane ◽  
Print Quality ◽  
Polyamide 11 ◽  
Powder Bed

Multi Jet Fusion (MJF) is a recently developed polymeric powder bed fusion (PBF) additive manufacturing technique that has received considerable attention in the industrial and scientific community due to its ability to fabricate functional and complex polymeric parts efficiently. In this work, a systematic characterization of the physicochemical properties of MJF-certified polyamide 11 (PA11) and thermoplastic polyurethane (TPU) powder was conducted. The mechanical performance and print quality of the specimens printed using both powders were then evaluated. Both PA11 and TPU powders showed irregular morphology with sharp features and had broad particle size distribution, but such features did not impair their printability significantly. According to the DSC scans, the PA11 specimen exhibited two endothermic peaks, while the TPU specimen exhibited a broad endothermic peak (116–150 °C). The PA11 specimens possessed the highest tensile strength in the Z orientation, as opposed to the TPU specimens which possessed the lowest tensile strength along the same orientation. The flexural properties of the PA11 and TPU specimens displayed a similar anisotropy where the flexural strength was highest in the Z orientation and lowest in the X orientation. The porosity values of both the PA11 and the TPU specimens were observed to be the lowest in the Z orientation and highest in the X orientation, which was the opposite of the trend observed for the flexural strength of the specimens. The PA11 specimen possessed a low coefficient of friction (COF) of 0.13 and wear rate of 8.68 × 10−5 mm3/Nm as compared to the TPU specimen, which had a COF of 0.55 and wear rate of 0.012 mm3/Nm. The PA11 specimens generally had lower roughness values on their surfaces (Ra < 25 μm), while the TPU specimens had much rougher surfaces (Ra > 40 μm). This investigation aims to uncover and explain phenomena that are unique to the MJF process of PA11 and TPU while also serving as a benchmark against similar polymeric parts printed using other PBF processes.

scholarly journals Washing treatment impact on print quality of screen printed knitted fabrics

2016 ◽  
Vol 21 (3) ◽  
pp. 817-826
Author(s):  
Mladen Stančić ◽  
Branka Ružičić ◽  
Nemanja Kašiković ◽  
Dragana Grujić ◽  
Dragoljub Novaković ◽  
...  
Keyword(s):  
Print Quality ◽  
Knitted Fabrics ◽  
Screen Printed

scholarly journals Erratum

1995 ◽  
Vol 15 (4) ◽  
pp. 719-719
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Electrical Impedance ◽  
Neonatal Rat ◽  
Print Quality ◽  
Resonance Imaging ◽  
Excitotoxic Injury ◽  
Cereb Blood Flow ◽  
Neonatal Rat Brain

Early Evolution and Recovery from Excitotoxic Injury in the Neonatal Rat Brain: A Study Combining Magnetic Resonance Imaging, Electrical Impedance, and Histology Menno van Lookeren Campagne, Jeroen B. Verheul, Klaas Nicolay and Robert Balázs [Originally published in J Cereb Blood Flow Metab 1994;14(6):JOll-J023] The print quality of Fig. 6G in the above article was poor and the figure therefore lacked the necessary detail. The publisher apologizes for this and reprints Fig. 6 , in its entirely, with the legend below. [Figure: see text]

scholarly journals Beyaz Yumurtacı Saf Hatlarda Yumurta Kalitesi Üzerine Yaş ve Kafes Katının Etkisi

2019 ◽  
Vol 7 (sp1) ◽  
pp. 173
Author(s):  
Hasan Eleroğlu
Keyword(s):  
Laying Hens ◽  
White Layer ◽  
Pure Line ◽  
Shape Index ◽  
External Quality ◽  
Egg Weight ◽  
Temperature And Humidity ◽  
Effect Of Age ◽  
Haugh Unit

In this study, the effects of coat difference and breeding age on the internal and external quality of the eggs were investigated in white laying hens in different cages. The eggs obtained from a total of one hundred fifty eggs White layer pure line hens at 24, 28, 32, 36 and 40 weeks of age that housing in individual cages in the Ankara Poultry Research Institute were used. Shape Index, egg weight (g), albumen height (mm), Roche scale, Haugh unit and shell strength (N) values were examined in 438 eggs obtained from these chickens found in these cages which are three tiers as upper, middle and bottom. In addition, temperature and humidity values in the tiers were recorded at 30-minute intervals during the study and then they were analysed. Statistically significant differences were calculated between temperature and humidity values measured in tiers. Although there was no difference between the tiers in terms of shape index and egg weight, the effect of age was significant. The effect of age and tiers difference on albumen height (mm) was insignificant. The Roche scale and shell strength (N) values were significantly influenced by the tier difference and breeding age. In general, it was concluded that the effect of the tier difference on the Haugh unit was insignificant, but the age was found to have an effect on the Haugh unit.

scholarly journals ANALYZING THE EFFECT OF DENSITY VALUE DEVIATION ON PRINT QUALITY

KREATOR ◽  
2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Soebardianto . ◽  
Septia Ardiani ◽  
Romi Setiawan
Keyword(s):  
Quality Control ◽  
Quality Parameters ◽  
Quality Level ◽  
Print Quality ◽  
Machine Material ◽  
Digital World ◽  
Quality Control Parameters ◽  
Density Values ◽  
Standard Density

The quality control activities, in particular the measurement of density values, are part of the quality control parameters carried out by each company. Companies sometimes forget about the quality parameters of the name, even though the quality can give the printed products a good guarantee in the eyes of consumers. To achieve the quality level, of course, the business does not stand idle, there are several things that need to be done or provided by the business to support the quality, namely man (human), machine (machine), material (material), and method (method). In the development of technology in an increasingly advanced digital world, companies want to continue to compete with a digital world by making inroads, this of course gives the products produced by the company a good or a good level of quality. In this discussion, there is an identification of problematic aspects arising from the deviation of density values as well as ways to obtain standard density values and factors that affect the quality of prints on book cover prints using a Heidelberg machine.Keywords—Quality Control, Density, Standart, Product, Deviation

Formation of the Printing Elements in the Photopolymer Material Used in Flexography

2014 ◽  
Vol 611-612 ◽  
pp. 883-891 ◽  
Author(s):  
Sanja Mahovic Poljacek ◽  
Tamara Tomasegovic ◽  
Tomislav Cigula ◽  
Miroslav Gojo ◽  
Diana Milcic
Keyword(s):  
Laser Ablation ◽  
Polymer Material ◽  
Major Influence ◽  
Printing Plate ◽  
Starting Point ◽  
Reproduction Process ◽  
Flexographic Printing ◽  
Printing Ink

Starting point of this paper is photopolymer printing plate used for flexographic printing. It is used for transfer of the printing ink onto the printing surface during the reproduction process. Photopolymer printing plate consists of several layers: polyester basis, photo sensitive polymer material and LAMS - Laser Ablation Mask. In the platemaking process the photosensitive material, which will form a printing plate, has to be several time exposed to different radiation in order to obtain a functional printability performance. LAMS layer has a role of masking in the exposure process. Upon pre-exposure, LAMS layer has to be removed by laser ablation only at the surfaces where photopolymer printing plate needs to be exposed. After ablation the exposures to UV lights follows and the plate will be finished with chemical removal of the unexposed parts of the polymer. Functionality of the finished printing plate has to be characterised and monitored in every procedure step because the formed image element on the printing plate has a major influence on the quality of the finished printed product. In this paper observing of the changes in the polymer material which is caused by exposure through LAMS layer will be performed. The aim is to measure the surface openings on the LAMS mask and to measure surface coverage (image elements) on the polymer material formed by exposure through the LAMS. Measuring will be made by image analysis software based on microscopic images of the control fields of differing halftone values. It is assumed that there will be a correlation between the LAMS openings and formed image elements on the printing plates. Preliminary results indicate that certain differences in image elements can be detected and are probably the consequence of the different amount of irradiated surface of the polymer material. Since the polymer material which forms the printing plate should be stable in the graphic reproduction process, results of the paper will explain the influence of UV exposures on polymerisation process and on the functional printability performance of the plates.

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