Tape Manufacturing Research Articles

Optimization of Cross-sectional Shapes of the Bi-2223/Ag Wires before Flat Rolling

Rolling process plays an important role in the manufacture of Bi-based high temperature superconductor tapes, and the plastic flow regularities of the superconducting wires during deformation will directly affect the ultimate quality of the tapes. In order to investigate the effect of cross-sectional shapes before flat rolling on the performance and homogeneity of the tapes, some numerical models of Bi-2223/Ag wires with different cross-sectional shapes including circular, square, elliptical and racetrack cross-sections are constructed during the rolling process. By comparing the relative density, logarithmic strain ratio and length-width ratio on the filaments, it is revealed that Bi-2223/Ag wire with special-shaped cross-section can achieve better conductivity than the round wire, in particular, the racetrack cross-sectional wire has the second best performance among four wires. Based on material processability and experimental condition, tri-pass racetrack drawing technique is employed to optimize the process and obtain racetrack cross-sectional wire. The rolling process of Bi-2223/Ag wire with racetrack cross-section causes more intensive deformation of filaments in the center of the tape and achieves the filaments with larger length-width ratio. Also, the deformation distribution of filaments verifies the numerical results. Consequently, the racetrack drawing technique can be utilized for a reference during the mechanical processing and to increase the current transmission capacities of Bi-2223/Ag tapes.

Chemical Fingerprinting of Adhesive Tapes by GCMS Detection of Petroleum Hydrocarbon Products

Pressure-sensitive adhesive tapes often represent key evidence of crimes such as assault, rape or homicide; thus, the development of analytical techniques able to contribute to a detailed characterization of these materials is of forensic importance. The gas chromatography-mass spectrometry (GCMS) analysis of the solvent extractable fractions of a suite of electrical and gaffer adhesive tapes spanning a range of colors and manufacturers identified a number of petroleum-derived hydrocarbons. Molecular and isotopic analyses of hydrocarbon constituents of complex materials have found wide analytical utility including the forensic investigation of oil spills and arson. Here, we investigate the utility of these techniques for characterizing the hydrocarbon composition of pressure-sensitive adhesive tapes for forensic correlation purposes. Subtle distinction of tape samples was evident in the GCMS distribution of several hydrocarbon groups including alkyl-naphthalenes, hopane and sterane biomarkers. Linear discriminant analysis of the abundances of these products provided high level differentiation of tape manufacturer. The distinction of different adhesive tape samples was further extended by measurement of their stable carbon isotopic values. The molecular and isotopic differences of the petroleum content of tapes are consistent with the use of different petroleum materials used in the manufacturing process and demonstrate the benefits of the combined use of complementary oil hydrocarbon characterization approaches. This study reveals the forensic potential of using established petroleum characterization methods for characterizing materials with a petroleum-derived hydrocarbon element.

Manufacture of (Bi,Pb)2Sr2Ca2Cu3O10-based tapes with a composite sheath

(Bi,Pb)2Sr2Ca2Cu3O10-based single-filament tapes were prepared using a pure Ag protective sheath in contact with the ceramic core and an external sheath consisting of Ni. The influence of the composite sheath geometry on the (Bi,Pb)2Sr2Ca2Cu3O10 phase formation kinetics was studied by in-situ synchrotron x-ray diffraction in a 8.5% O2 – 91.5% N2 gas mixture and was found to depend strongly on the sheath architecture as a consequence of differences in the oxygen supply between the ceramic core and the outer atmosphere. Owing to the efficient protection of the pure Ag layer against Ni diffusion, the critical temperature of the (Bi,Pb)2Sr2Ca2Cu3O10 phase is unaffected. Critical current densities as high as 35 kA/cm2 (77K, self field) were obtained in a single heat treatment when a slow cooling rate was used. The ceramic density was significantly improved in comparison with that of tapes prepared using only pure Ag as sheath material and heat treated once. This effect can be attributed to the higher mechanical strength of the composite sheath at elevated temperatures, which prevents the development of an otherwise significant porosity during the growth of the superconducting crystallites.

Drying of Thin Films of Polymer Solutions Coated over Impermeable Substrates

The manufacturing of adhesive tapes, photographic films, magnetic media, and many other products involves the coating and drying of thin films of polymeric solutions or emulsions over an impermeable substrate. Wet thickness may vary from 1 micron to 500 microns and solid content from 3% to 50% or more. The drying process generally occurs in convective ovens, where air temperature, air flow rate, and solvent partial pressure may be adjusted. In many cases, it is the manufacturing step that controls the productivity; therefore, it is very important to optimize the oven conditions to minimize the oven residence time without causing defects on the coated film and keeping the residual solvent inside the final product within specification limits. A drying model and a simulation software based on it were developed in order to solve the transient mass and heat transfer equations that describe the drying of a polymer solution containing two different solvents. The resulting system of equations shows strong non-linearity due to the free surface and the dependence of diffusion coefficients on solvent concentration and film temperature. The integration in time was performed with a fully implicit method, and at each time step, Newton's method was used to solve the resulting non-linear system of algebraic equations. An example of using the drying simulator to optimize an industrial adhesive tape line is discussed. The gain in productivity achieved by the analysis was greater than 40%.

Properties of pressure‐sensitive adhesive tapes with soft adhesives to human skin and their mechanism

The use of soft adhesives in the manufacture of pressure-sensitive adhesive tapes has recently increased. The dermal peeling force of adhesive tapes with soft adhesives was studied. Four kinds of adhesive tapes with adhesives of different softness were made, by adding varying amounts of isopropyl myristate as a softener. The tapes were applied on the flexor side of the forearm of six healthy male volunteers. The dermal peeling force, the amount of stripped corneocytes, the level of pain when the tapes were removed and the degree of penetration of adhesives into the sulcus cutis (skin furrows) were evaluated at 1 and 24 h after application of the tapes. Furthermore, a skin model panel (a sulcus cutis and crista cutis model panel) and a crista cutis model panel were constructed from a general stainless-steel panel, and the peeling force of the tapes against the model panels was measured. As the softness of adhesives increased, the peeling force against a general stainless-steel panel with a flat surface decreased, although the peeling force against human skin did not significantly change. The amount of stripped corneocytes on the removed tapes and the level of pain when the tapes were removed decreased with the increase in softness of the adhesives. These results suggest that adhesive tapes with soft adhesives that contain isopropyl myristate as a softener are suitable for the skin. Furthermore, the degree of penetration of adhesive into the sulcus cutis increased as the softness of adhesives increased. Upon evaluation of the peeling force against the model panels, as the softness of adhesives increased, there was a slight decrease in the peeling force against the skin model panel, while there was a remarkable decrease in the peeling force against the crista cutis model panel. These results suggest that the lack of change in the dermal peeling force as the softness of adhesives increased was caused by penetration of soft adhesive into the sulcus cutis, and that the decrease in the amount of stripped corneocytes was caused by a decrease in the peeling force against the crista cutis, which consists of corneocytes mainly removed by the tapes.

Factors Influencing the Green Body Properties and Shrinkage Tolerance of LTCC Green Tapes

Low‐temperature co‐fired ceramics (LTCC) is a powerful technology for the manufacture of integrated electronic devices. To fulfill the needs of miniaturization, the applied materials must be of constant quality and the manufacturing processes must be well controlled. The reproducibility in shrinkage is one of the most important quality issues of LTCC tapes. To guarantee the customer a narrow shrinkage tolerance, the tape producer must know the important influencing factors of tape manufacturing on shrinkage. In this work, the effects of slurry composition, tape‐casting parameters like casting speed and opening of the blades, and tape handling on the sintering shrinkage behavior were investigated by using design of experiments. The investigation showed that the green density and therefore the shrinkage values of tapes depend considerably on the variation of the solvent mixture. Furthermore, significant interactions were quantified between the tape‐casting velocity as well as the particle size and the shrinkage behavior. The shrinkage values were also influenced by mechanical deformations of the tapes before firing.

Magnetic evaluation of advanced metal-evaporated tape in an advanced linear tape drive

Demand for increased data storage has resulted in the development of various types of magnetic tapes. To achieve higher recording density, tape manufacturers are developing thin-film tapes, such as advanced metal-evaporated (AME) tape, for use in linear tape drives. In recent studies, these new AME tapes have demonstrated sustainable mechanical durability at low tensions suitable for use in linear tape drives. An evaluation of the magnetic performance of these AME tapes including the impact of tape cupping and initial edge quality was the goal of this study. Head output, dropouts, head–tape interface friction, and lateral tape motion (LTM) were monitored throughout testing. As track widths continue to narrow, LTM has become one of the critical limitations of magnetic performance. To more accurately measure LTM during drive development, a new method involving the output voltage of a head-read element that has been adjusted to be halfway off the recorded track on tape was implemented (LTM M). It is shown that positively cupped AME tapes will result in similar head output and fewer dropouts than the current MP tapes. The negatively cupped AME sample produced the lowest head output data and the highest amount of dropouts of all the tapes evaluated in this investigation. All the tapes evaluated demonstrated similar values of LTM when monitored at the center of the tape. When LTM was monitored at the lower edge of the tape, the positively cupped AME tape with the worst relative edge contour length resulted in the highest LTM M. As found in previous studies, AME tapes produced slightly lower values of coefficient of friction than the MP tapes. From this investigation, positively cupped AME tapes with good initial relative edge contour length are recommended for use in linear tape drives, similar to those used in this study.

Failure Mechanisms of Advanced Metal Evaporated Tape in an Advanced Linear Tape Drive

Demand for increased data storage has resulted in the development of various types of magnetic tape. To achieve higher recording density, tape manufacturers are developing thin-film tapes, such as advanced metal evaporated (AME) tape, for use in linear tape drives. The structure of AME tape is fundamentally different from metal particulate (MP) tape. The goal of this study was to determine the methods and mechanisms associated with failure of AME tapes as well as to investigate the effect of tape cupping and initial edge quality on tape durability in an advanced linear tape drive. It is shown that AME tape exhibits a slightly lower coefficient of friction than the MP. The negatively cupped AME tape demonstrated a greater value of lateral tape motion peak-to-peak amplitude than both of the positively cupped AME samples as well as the MP tape sample. It was found that poor initial tape edge condition plays a large role in debris generation. For these reasons, positively cupped AME tapes with good initial relative edge contour are recommended for use in linear tape drives. The dominant mechanism of failure for the AME samples is adhesive wear resulting in removal of the DLC overcoats and sublayers. Review led by Tom Karis

Measurement and mechanism of pole tip recession with advanced metal evaporated tape at low tension in a linear tape drive

Increased head-to-tape spacing in a magnetic tape drive causes signal loss. Pole tip recession (PTR) is a type of differential wear that occurs with tape heads and increases the effective head-to-tape spacing. The extent and mechanism of PTR that occurs when using metal particle (MP) tape has been examined by various authors and is well documented. To achieve higher recording density, tape manufacturers are developing thin-film tapes, such as advanced metal evaporated (AME) tape, for use in linear tape drives. The structure of AME tape is fundamentally different from MP tape and AME tape must be run at lower tension. The goals of this study are to determine the amount of PTR that occurs and to investigate the mechanism by which PTR proceeds when AME and MP tapes are rubbed against a commercial head in a linear tape drive at low tension. Atomic force microscopy (AFM) was used to measure PTR after interval sliding distances. It is shown that use of AME tape led to lower PTR than use of MP tape, and the probable mechanism of PTR growth is three-body abrasion, with different types of abrasive debris from the two tapes.

Characterization of low AC loss elementary and assembled BSCCO conductors

A European consortium has progressed towards elementary and assembled conductorsviable for AC applications in the project ACropolis. The main goal was to achieve lowAC losses and high critical current densities in tapes developed for AC coils,transformers and cables. In order to verify the performance of tapes an extensivecharacterization programme was carried out. The dependence of critical current and AClosses on the parameters of the tape manufacturing process were scrutinized.Furthermore, SEM-EDX and DTA/TG analyses were performed to study thematerial microstructure, and the diffusion coefficient of oxygen through differentmatrix metals was measured. The homogeneity of the tapes was verified withmagnetic knife and Hall sensor experiments. Transport current measurements wereperformed at different mechanical stress conditions and also the distribution ofcritical current along long tapes was determined with a quasi-continuous four-pointmeasurement. The results confirmed that the low AC loss conductors can be produced onan industrial scale and they are competitive in power engineering applications.

A Spectral Identity Mapper for Chemical Image Analysis

Generating chemically relevant image contrast from spectral image data requires multivariate processing algorithms that can categorize spectra according to shape. Conventional chemometric techniques like inverse least squares, classical least squares, multiple linear regression, principle component regression, and multivariate curve resolution are effective for predicting the chemical composition of samples having known constituents, but they are less effective when a priori information about the sample is unavailable. We have developed a multivariate technique called spectral identity mapping (SIM) that reduces the dependence of spectral image analysis on training datasets. The qualitative SIM method provides enhanced spectral shape specificity and improved chemical image contrast. We present SIM results of spectral image data acquired from polymer-coated paper substrates used in the manufacture of pressure sensitive adhesive tapes. In addition, we compare the SIM results to results from spectral angle mapping (SAM) and cosine correlation analysis (CCA), two closely related techniques.

Mechanical, hygroscopic, and thermal properties of metal particle and metal evaporated tapes and their individual layers

AbstractMechanical and thermal properties of magnetic tapes and their individual layers strongly affect the tribology of magnetic head–tape interface and reliability of tape drives. Dynamic mechanical analysis, longitudinal creep, lateral creep, Poisson's ratio, the coefficient of hygroscopic expansion (CHE), and the coefficient of thermal expansion (CTE) tests were performed on magnetic tapes, tapes with front coat or back coat removed, substrates (with front and back coats removed), and never‐coated virgin films of the substrates. Storage modulus and loss tangent values were obtained at a frequency range from 0.016 to 28 Hz, and at a temperature range from −50 to 150 or 210°C. Longitudinal creep tests were performed at 25°C/50% RH, 40°C/25% RH, and 55°C/10% RH for 50 h. The Poisson's ratio and lateral creep were measured at 25°C/50% RH. CHE was measured at 25°C/15–80% RH. CTE values of various samples were measured at a temperature range from 30 to 70°C. The tapes used in this research included two magnetic particle (MP) tapes and two metal evaporated (ME) tapes that were based on poly(ethylene terephthalate) and poly(ethylene naphthalate) substrates. The master curves of storage modulus and creep compliance for these samples were generated for a frequency range from 10−20 to 1015 Hz. The effect of tape manufacturing process on the various mechanical properties of substrates was analyzed by comparing the data for the substrates (with front and back coats removed) and the never‐coated virgin films. A model based on the rule of mixtures was developed to determine the storage modulus, complex modulus, creep compliance, and CTE for the front coat and back coat of MP and ME tapes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1319–1345, 2004

Effect of processing defects on stress-strain-I/sub c/ for AgMg sheathed Bi-2212 tapes

Manufacture of multifilamentary BSCCO tapes involves rolling of billets to final form. In BSCCO-2212 tapes, one method used to control the microstructure and increase J/sub c/ is intermediate annealing during the deformation process. At times, small bubbles have been observed on the tapes after annealing. Although such bubbles do not remain at the end of fabrication, the question of possible effect on superconducting performance has been studied. The sections that had bubbles after annealing were marked and the fabrication process completed on the tape. After final reaction of the tape, comparisons of stress-strain-I/sub c/ for bubbled and nonbubbled sections were performed. Here we present electrical, mechanical and microstructural studies on bubbled and bubble-free sections of tape. It was found that sections with bubbles had lower I/sub c/ than sections with no bubbles, though both had similar onset of I/sub c/ degradation at /spl sim/0.40%.

Dynamic mechanical and thermal analyses of magnetic particle and metal evaporated tapes and their individual layers

AbstractThe mechanical and thermal properties of magnetic tapes and their individual layers strongly affect the tribology of the magnetic head–tape interface. Dynamic mechanical analysis and thermomechanical analysis tests were performed on magnetic tapes, tapes with front coat or back coat removed, substrates (with front and back coats removed), and never‐coated virgin films of the substrates. Storage modulus and loss tangent were obtained at a frequency range from 0.016 to 28 Hz, and at a temperature range from −50 to 150 or 210°C. Coefficients of thermal expansion (CTE) of various samples were measured at a temperature range from 30 to 70°C. The tapes used in this research include two magnetic particle (MP) tapes and two metal evaporated (ME) tapes based on poly(ethylene terephthalate) and poly(ethylene naphthalate) substrates. The master curves of storage modulus for these samples were generated for a frequency range from 10−20 to 1015 Hz. The effect of the tape manufacturing process on the dynamic mechanical properties of substrates was analyzed by comparing the data for the substrates (with front and back coats removed) and the never‐coated virgin films. A model based on the rule of mixtures was developed to determine the storage modulus, complex modulus, and CTE for the front coat and back coat of MP and ME tapes. To validate the procedure, data for these individual layers were then used to calculate the corresponding properties of the finished tape. The predicted results were compared with the experimental measurements. The data obtained in the study are also discussed in light of previously published lateral contraction, Poisson's ratio, CTE, and CHE (coefficient of hygroscopic expansion) data. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 548–567, 2003

Technique development and measurement of Poisson's ratio, lateral creep behavior, and thermal and hygroscopic expansion of individual layers in magnetic tapes

AbstractAn experimental technique was developed to measure the Poisson's ratio (lateral contraction over longitudinal elongation), lateral creep, and both thermal and hygroscopic expansion of thin polymeric films. A so‐called profile‐matching method was developed to measure the lateral and longitudinal deformation with the help of a laser scan micrometer. A thermomechanical analyzer was used to measure the coefficient of thermal expansion (CTE). The laser scan technique was also used to measure the coefficient of hygroscopic expansion (CHE). The measurements were performed on magnetic tapes, substrates, and tapes with front coat or back coat, or with both coats stripped. A model based on the rule of mixtures was developed to determine the Poisson's ratio, lateral and longitudinal deformation behavior, and thermal expansion of the front coat and back coat. To investigate the mechanical degradation of the substrates during tape manufacturing, the data for substrate with the front and back coats removed from the tape, were compared with the data for the never‐coated virgin film. The relationship between the molecular structure and the degradation mechanism of the substrates is discussed. The magnetic tapes used in this research include two metal particle (MP) tapes and two metal evaporated (ME) tapes that use polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) substrates. Longitudinal and lateral deformation tests were performed at 25 ± 0.5°C and 50 ± 2%RH, and thermal expansion was measured from 15 to 70°C. The CHE was measured at 25 ± 0.5°C and 15–80%RH. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2082–2096, 2003

On the UV Curability and Mechanical Properties of Novel Binder Systems Derived from Poly(ethylene terephthalate) (PET) Waste for Solventless Magnetic Tape Manufacturing, 2. Methacrylated Oligoesters

On the UV Curability and Mechanical Properties of Novel Binder Systems Derived from Poly(ethylene terephthalate) (PET) Waste for Solventless Magnetic Tape Manufacturing, 2. Methacrylated Oligoesters

Preparation of (Bi,Pb) 2Sr 2Ca 2Cu 3O x precursor powders by a modified polyethylene glycol based sol–gel process

A modified sol–gel process based on polyethylene glycol has been developed for preparing (Bi,Pb) 2Sr 2Ca 2Cu 3O x precursor powders in view of Ag-sheeted tape manufacture. A careful control of the pH and concentration temperature yields an amorphous gel, which can be converted to a fine and extremely reactive powder. The reactions taking place during the process were studied. Various calcination conditions were used in order to obtain precursor powders having different characteristics (grain size distribution, phase assembly). The influence of precursor preparation parameters on the formation of the (Bi,Pb) 2Sr 2Ca 2Cu 3O x phase in pressed pellets and on some of its physical properties is presented and discussed.

Continuous Monitoring of Resin Content in Prepreg Unidirectional Tapes by Beta-Ray Method

A beta-ray monitoring technique has been developed to measure the resin content during the manufacture of prepreg unidirectional tapes by solution impregnation process. A series of calibration relations have been obtained for aramid, carbon and glass fibres reinforced epoxy prepreg tapes, and good agreements with resin content have been shown by the beta-ray system and conventional solvent extraction method. Moreover, the effect of the variation of the fibre areal weight on measuring accuracy has been analysed.

On the UV Curability and Mechanical Properties of Novel Binder Systems Derived from Poly(ethylene terephthalate) (PET) Waste for Solventless Magnetic Tape Manufacturing, 1. Acrylated Oligoesters

PET waste obtained from beverage bottles was depolymerized by a glycolysis reaction, using diethylene glycol (DEG) as the glycolyzing system and manganese acetate as a transesterification catalyst. The glycolysis reaction was conducted at two different molar ratios of PET : DEG, namely 1 : 2.15 and 1 : 1.03, for the sake of obtaining oligoester polyols of varying molecular weights. The hydroxyl values of the obtained oligoesters were 361 and 330 mg KOH/g. Modification of these oligoester polyols was carried out by acrylation reactions of the available hydroxyl groups by acryloyl chloride. This gave acrylated oligoesters curable under UV or electron beam irradiation. The curability of these newly synthesized acrylated oligoesters was tested by UV irradiation, in the presence of 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone (BDMB) as a photo initiator. This gave cured films of high mechanical properties when the acrylated oligoesters were either cured alone or as mixtures with other commercially available diacrylate/dimethacrylate monomers. The measured tensile properties were in the range of 4.62–45 MPa for maximum tensile strength and 0.074–2.0 GPa for Young's modulus.

Electrical and stability properties and ultrasonic microscope characterisation of low temperature co-fired ceramics resistors

This paper presents systematic investigations of electrical and stability properties of various low temperature co-fired ceramics (LTCC) resistors. One of the goals of this work was to check the compatibility of LTCC materials (tapes, resistive and conductive inks) from various manufacturers. Three commercially available green tapes and three LTCC resistor/conductor systems were examined. The resistive inks with 1 kΩ/sq. nominal sheet resistance were used. Buried (inside) and surface resistors were laminated and fired according to the tape manufacturers’ recommendations. The influence of dimensional effect on sheet resistance and hot temperature coefficient of resistance, the temperature dependence of resistance in a wide temperature range (from −180°C to +130°C), long-term stability of thermally aged as-fired resistors (150°C, 500 h) and durability to high-voltage micro- or nanosecond pulses (50 ns pulses with 4000 V/mm maximum electric field or 10 μs ones with 700–1000 V/mm electrical field) were carried out for electrical and stability characterisation of LTCC resistors. Non-destructive scanning acoustic microscope diagnostics was applied for structure investigation and estimation of lamination and cofiring process quality of buried LTCC resistors.