Development and Characterization of Biobased Polyamide 56/Polyethylene Terephthalate Composite Fibers

The present research studied the production process and performance of biobased PA56 (polyamide 56) and PET (polyethylene terephthalate) composite fibers through melt side-by-side spinning. The results showed that biobased PA56 and PET composites with strength of 4.0–4.3 CN/dtex were prepared by applying a spinning speed of 4,000–4,050 m/min, draw ratio of 2.50–2.70, first heat roll temperature of 80–90 °C, second heat roll temperature of 160–165 °C, and the addition of 5% compatibilizer between the two components. The fibers and fabric showed high moisture absorption, good air permeability, and excellent antistatic properties. The saturated moisture absorption rate was 11.2%, the air permeability was 9680 g/(m2·d), and the specific resistance was 1080*1010 Ω·m.

Evolution of Microstructure and Mechanical Properties of Mg-6Al Alloy Processed by Differential Speed Rolling upon Post-Annealing Treatment

Magnesium-6 wt.% aluminum (Mg-6Al) alloy plates with a 6-millimeter thickness were processed from an initial 12-millimeter thickness by differential speed rolling (DSR), with a 0.76-millimeter thickness reduction per pass using a speed ratio of 2, preheating temperature of 315 °C, and roll temperature of 265 °C. The effects of annealing temperature of 250, 275, and 300 °C with a corresponding holding time of 15 min on the microstructure, texture, and mechanical properties were investigated. Key results show that dynamic recrystallization (DRX) occurred during the roll processing, resulting in a greatly reduced grain size. In addition, the basal pole of the as-rolled plate was inclined to the rolling direction (RD) by ~20°, due to the shear strain introduced during DSR. Subsequent annealing caused grain growth, eliminated the basal pole inclination towards the RD, and slightly increased the pole intensity. Compared with the as-rolled plate, the average of the ultimate tensile strength (UTS) and the yield strength (YS) of the annealed plates decreased, while the average elongation at fracture (εf) increased. With the annealing temperature of 275 °C, the plate achieved a good combination of mechanical properties with UTS, YS, and εf being 292.1 MPa, 185.0 MPa, and 24.9%, respectively. These results suggest that post-roll annealing is an effective way to improve the mechanical response of this Mg alloy processed by DSR.

Machine Information System for Bajaj Rotobar using PLC

Looking towards the importance of improved contamination-free of ginned cotton and a high degree of reliability and efficiency in the performance of machinery in ginning setup, rejuvenation, and automation in ginning is required. So, it becomes mandatory to continuously monitor the performance of the ginning machine. The main objective of the project is to monitor the performance of the machine and its troubleshooting with the help of the MIS system through PLC logic. The temperature control system plays a very important role in various fields like metallurgy, building materials, food, etc. By using this temperature control system, we can set temperatures as per our requirements. With the help of a PLC-based MIS system, we can create the time vs temperature Graph. Also, we can monitor the roll temperature hot spot with help of temperature sensor feedback. It will be very advantageous in calculating the performance of machines and accordingly do preventive maintenance which will lead to an increase in productivity.

Thermal Camber and Temperature Evolution on Work Roll during Aluminum Hot Rolling

Flatness is an important quality characteristic for rolled products. Modern hot rolling mills are equipped with actuators that can modify the uneven thickness distribution across the width of the strip (crown), taking into account online measurements of various process parameters such as temperature, force and exit strip profile, either automatically or manually by the operator. However, the crown is also influenced by many parameters that cannot easily be measured during production, such as work roll temperature evolution through thickness and roll geometric variation due to thermal expansion (thermal camber). These have an impact on the strip flatness. In this paper, a thermo-mechanical finite element model on LS-DYNA™ software was utilized to predict the influence of process parameters, and more specifically strip temperature, cooling strategy (application of cooling on the entry or entry and exit side simultaneously) and roll core temperature, on the evolution of roll temperature and thermal camber. The model was initially validated with industrial data. The results indicate that the application of both entry and exit cooling is ~30% more efficient compared to the entry cooling only, thus the thermal camber will be reduced by 2 μm. A hotter roll (380 K) is more stable compared to the cold roll (340 K), showing also an improvement of 2 μm. The hotter roll will also reach a thermal steady state on the surface faster compared to the colder one, without making a significant difference on the steady state temperature. Strip temperature plays a roll in the thermal camber evolution, but it is a less important parameter compared to cooling strategy and roll temperature.

Systematic Investigation on the Structure-Property Relationship in Isotactic Polypropylene Films Processed via Cast Film Extrusion

The effect of cast film extrusion processing conditions, such as the chill-roll temperature, temperature of the melt, and line speed, on the structure of different isotactic polypropylene homo- and random copolymers has been investigated by means of Small- and Wide-Angle X-ray Scattering (SAXS and WAXS) and correlated to stiffness and haze. Stiffness and transparency have been found to be strongly dependent on the temperature of the chill-roll. Interestingly, line speed has been found to affect the total crystallinity when the chill-roll temperature is increased, while an overall minor effect of the melt temperature was found for all cast films. The polymer characteristics, defined by the catalyst nature and comonomer content, affect the final material performance, with the single-site catalyzed grades performing better in both mechanics and optics. Haze levels were found to correlate with the mesophase content rather than to α-crystallinity and to be dependent on the domain size for all grades. The remarkably low haze levels reached by the single-site grade with higher isotacticity can arise from high nucleation rate and orientational effects, which ultimately yield smaller and smoother scattering domains.

Development of Breathable Films from Blends of Low-Density Polyethylene and Thermoplastic Polyester Elastomer

The main drawback of low-density polyethylene (LDPE) film for packaging of fresh fruit or vegetables is low moisture breathability. This study developed breathable films by blending LDPE with thermoplastic polyester elastomer (TPEE). LDPE and TPEE in the weight ratios of 95/5, 90/10, 80/20, 70/30, and 60/40 wt% were melt blended and then extruded into films using a cast film extruder. Clarity of films was characterized by UV-VIS spectroscopy. Tensile properties, tear resistance, the degree of crystallinity, and morphology of blend films were evaluated. Water vapour transmission rate (WVTR) was investigated using a desiccant method. The prepared films were transparent. However, the UV-VIS transmittance was reduced slightly. Blending TPEE of more than 10 wt% reduced the modulus but increased elongation at break. It did not impact on the tensile strength of the blends. Since LDPE and TPEE are immiscible, applied stress during extrusion pulled them apart at the interphase boundaries creating micro-pores. As a result, these micro-pores reduce tear resistance significantly but increase WVTR of the blend films. Using a blend ratio of 90/10 wt%, the effect of chill-roll temperature and nip-roll velocity on film properties were studied. It was found that nip-roll velocity had more influence on WVTR than chill-roll temperature due to elongation of the pores.

System of Energy-Saving Optimal Control of Metal Heating Process in Heat Treatment Furnaces of Rolling Mills

Heat-treatment furnaces for workpiece pre-rolling heating are heating plants of the transition type where sheet slabs with various characteristics are simultaneously heated. The heat treatment furnace performance is directly connected with the efficient operation of the rolling mill process plants. The irregular operation pace of the rolling mill complicates the implementation of energy-saving workpiece pre-rolling heating modes and increases the risk of delivering an insufficiently heated workpiece. This paper proposes the system of controlling the heat mode of the heat-treatment furnace by the criterion of fuel consumption rate minimization and controlling over a real heated state of a sheet slab located at the workpiece pushing from the heat-treatment furnace to the rolling mill. The author uses a simplified mathematical model of workpiece heating intended for defining the energy-saving heating path accounting for the impact of technological and structural constraints in the workpiece heating process. The calculation is conducted in real time and allows obtaining an optimal heating path of each workpiece at the moment of its loading into the heat-treatment furnace. The paper considers the necessity of interaction and the interaction itself of the subsystems performing the key function in the energy-saving operation mode of the heat-treatment furnace at workpiece heating. The author studied the subsystems of forecasting the workpiece heating time on the state of the rolling mill equipment and the geometrical dimensions of the rolled band, control over gaseous fuel burning in the heat-treatment furnace operation space, system of control over the workpiece heating state before pushing from the heat-treatment furnace and forecasting the roll temperature after the treatment of the rolling mill roughing train.

Simulation of Thermal Stress and Fatigue Life Prediction of High Speed Steel Work Roll during Hot Rolling Considering the Initial Residual Stress

Considerable residual stress is produced during heat treatment. Compressive residual stress at the shell is conductive to improving the thermal fatigue life of a work roll, while tensile stress in the core could cause thermal breakage. In hot rolling, thermal stress occurs under the heating-cooling cycles over the roll surface due to the contact with the hot strip and water spray cooling. The combination of thermal stress and residual stress remarkably influences the life of a work roll. In this paper, finite element method (FEM) simulation of hot rolling is performed by treating the residual stress as the initial stress. Afterwards, the effects of the initial roll temperature and cooling conditions on thermal stress considering the initial residual stress are discussed. Lastly, the thermal fatigue life of a work roll is estimated based on the strain life model. The higher initial roll temperature causes a higher temperature but a lower compressive thermal stress at the roll surface. The surface temperature and compressive stress increase significantly in the insufficient cooling conditions, as well as the center tensile stress. The calculation of the fatigue life of a work roll based on the universal slopes model according to the 10% rule and 20% rule is reasonable compared with experimental results.

PENERAPAN HAZARD ANALYSIS AND CRITICAL CONTROL POINT (HACCP) PADA PROSES PRODUKSI WAFER ROLL [Implementation of Hazard Analysis and Critical Control Point (HACCP) in Production of Wafer Roll]

The purpose of this study was to determine the application of Hazard Analysis and Critical Control Points (HACCP) to identify and prevent potential hazards in the production process of chocolate roll wafers at PT. X. The production process of wafer roll at PT. X consisted of mixing raw materials, filtering, roasting, rolling a wafer roll, filling cream, cutting, decreasing wafer roll temperature, packaging, and X-ray detection. The implementation of a quality assurance system must be carried out at every stage of processes to prevent microbiological chemical, and physical hazard pollution, and maintaining product quality. The study was conducted using a survey method, by directly following the entire process of making chocolate roll wafers from the receiving of raw materials to the final product in the packaging. The data was analyzed using descriptive analysis method. The application of the HACCP system at PT. X through two steps, that were preliminary hazard analysis step and hazard analysis step. The results showed that the X-ray detection pathway found CCP contamination of foreign objects with significant hazards in the form of metal parts in the product. Preventive actions taken included separating and marking deviant products, repairing the auto stop system, and visual observation by employees on X-ray detection machines.