Preform Material Research Articles

Pengendalian Kualitas Menggunakan Metode Six Sigma dan FMEA untuk Mengurangi Reject Material Preform pada Industri AMDK

One of the stages of bottled drinking water production at PT X is bottle making using preform material. Preform material is made from PET (Polyethylen Terphtalate). During the production process, there are preform material rejects such as broken bottles, unstable bottle thickness, white preforms, pinched bottles, and white bottles. The total preform material rejects during January to October 2022 amounted to 0.98% or there were 234,504 pcs of preform rejects from the total production of 23,905,322 bottles. The percentage of preform material rejects is above the company standard of 0.5%, so it requires Six Sigma and FMEA methods to reduce these rejects. The proposed improvement recommendations are blowing machine operation checklist form, preform specification form for suppliers, and training schedule form. However, the recommendation that was implemented was the blowing machine operation form checklist because machine malfuction was the main factor causing preform material rejects based on FMEA analysis. The recommendation was implemented for one month in November and succeeded in reducing preform material rejects by an average of 0.86% or there were preform rejects of 298,641 pcs of preforms from a total production output of 34,599.74 bottles during January to November 2022. The final calculation after the implementation of the proposed improvements shows that there is a decrease in the DPMO value from 1961.93 to 1726.26 and an increase in the sigma level value of 4.42 sigma which was previously 4.38 sigma, from this value it shows that the sigma level has increased by 0.04 sigma.
 Keywords: Reject, Preform Material, Six Sigma

Resin Film Infusion Process: Numerical Algorithm

The liquid composite molding (LCM) belongs to the composite manufacturing processes. In this family, a fabric preform material is placed into the mold cavity, and then it is impregnated with a thermosetting resin of low viscosity, until the fiber skeleton is entirely filled and finally polymerized to create a polymeric composite product. Due to its advantages, LCM has gained attention and competitiveness against other composite manufacturing processes. The resin film infusion (RFI) belongs to the LCM family, but unlike the other variants, such as resin transfer molding (RTM) and vacuum assisted resin infusion (VARI), in which the liquid resin is injected or infused into the mold cavity, the resin in the RFI process is placed into the mold cavity in the semi-cured state. Then, under pressure and temperature, the resin film will be liquefied and impregnated the fibrous reinforcement in the thickness direction. This particularity permits to RFI to fabricate large complex composite structures and reduce significantly the equipment cost as compared to the conventional resin transfer molding processes. However, as this variant used only a vacuum bag as the upper half-mold, the fabricated part has non-uniformity in the thickness, low dimensional tolerances and low fiber volume fraction. The main objective of this paper is to propose a numerical algorithm allowing to study the influence of part thickness on the RFI’ filling time. Numerical simulation is based on the explicit finite difference method. The results obtained show that the filling time increases parabolically with the part thickness.

In-Plane Permeability Measurement of Biaxial Woven Fabrics by 2D-Radial Flow Method

Abstract The accurate characterization of fabrics used in vacuum assisted resin transfer molding (VARTM) is essential in order to model the flow through these porous preforms. A wide range of these fabrics are available for composite manufacturing through VARTM and thus brings about a need to opt a methodology which characterizes the in-plane permeability of these preforms. These permeability values can then be used in simulations that can track the flow front progression and mold filling time. This work identifies the permeability of an E-glass fabric based on Darcy's law. Woven fabric having areal weight of 200 grams per square meter (gsm) is under consideration. The experiments are conducted at constant pressure conditions using 2D Radial flow method. Stereo microscopy of the preform material is done for detailed study of the weaving pattern. It is concluded that plain woven fabric exhibits anisotropic behavior when tested for in-plane permeability. Permeability is found to be higher in a direction which offers more interspacing between adjacent fibers threads causing more resin to flow in this direction.

Blowing Kinetics, Pressure Resistance, Thermal Stability, and Relaxation of the Amorphous Phase of the PET Container in the SBM Process with Hot and Cold Mold. Part II: Statistical Analysis and Interpretation of Tests.

The technology of filling drinks without preservatives (such as fresh juices, iced tea drinks, and vitaminized drinks) is carried out using hot filling. Mainly due to the production costs and lower carbon footprint, polyethylene terephthalate (PET) bottles are increasingly used in this technology. In this paper, the main aim is to describe and interpret the results of statistical analysis of the influence of the temperature of the blow mold in the SBM (stretch blow molding) process and the method of hot filling on the macroscopic and microscopic bottle properties. The macroscopic bottle properties were defined by the thickness profile, pressure resistance, thermal stability, and the coefficients of blowing kinetics. In addition, the influence of the SBM process on the microscopic PET material properties (in the bottle) relative to the microscopic preform properties was analyzed. The microscopic properties were defined by the degree of crystallite, density, and relaxation of the amorphous phase of the PET material. For this purpose, response surface experiments were performed for the two analyzed factors, i.e., the temperature of the blow mold and the method of hot filling. The sample size was investigated to determine the minimum number of repetitions (number of bottles in the measurement series) required to achieve acceptable measurement uncertainty. The research conducted shows that, despite fulfilling the postulate of acceptable measurement uncertainty, in terms of the power of ANOVA (analysis of variance) in DOE (design of experiment), the accepted number of bottles in the measurement series is too small. The tests of the bottle material density, material crystallite, and relaxation of amorphous phase relative to the preform material density, material crystallite, and relaxation of amorphous phase show that microcavity effects occur during the deformation of the PET material, and that these are associated with the orientation of the microstructure. The blow kinetics study shows that there is a gradient of flow of the bottle material over the thickness of the bottle wall during blowing, and it has been deduced that the air temperature between the blow mold and the wall of the blown bottle has an impact on the kinetics of blowing the bottle.

Blowing Kinetics, Pressure Resistance, Thermal Stability, and Relaxation of the Amorphous Phase of the PET Container in the SBM Process with Hot and Cold Mold. Part I: Research Methodology and Results.

The technology of filling drinks without preservatives (such as fresh juices, iced tea drinks, vitaminized drinks) is carried out using hot filling. Mainly due to the production costs and lower carbon footprint, polyethylene terephthalate bottles, commonly called PET, are increasingly used in this technology. In this paper, the main aim is to describe the statistical analysis methodology of the influence of the temperature of the blow mold in the SBM process and the method of hot filling on the macroscopic and microscopic bottle properties. The macroscopic bottle properties were defined by the thickness profile, pressure resistance, thermal stability, and the coefficients of blowing kinetics. Moreover, the influence of the SBM (stretch blow moulding) process on the microscopic PET material properties (in the bottle) relative to the microscopic preform properties was analyzed. The microscopic properties were defined by the degree of crystallite, density, and relaxation of the amorphous phase of the PET material. For this purpose, response surface experiments were performed for the two analyzed factors (independent variables), i.e., the temperature of the blow mold and the method of hot filling. The sample size was investigated to determine the minimum number of repetitions (number of bottles in the measurement series) required to achieve acceptable measurement uncertainty. The research conducted shows that despite fulfilling the postulate of acceptable measurement uncertainty, in terms of the power of ANOVA (analysis of variance) in DOE (design of experiment) the accepted number of bottles in the measurement series is too small. The tests of the bottle material density, material crystallite, and relaxation of amorphous phase relative to the preform material density, material crystallite, and relaxation of amorphous phase show that the microcavity effects occur during the deformation of the PET material, and that these are associated with the orientation of the microstructure. The blow kinetics study shows that there is a gradient of flow of the bottle material over the thickness of the bottle wall during blowing, and it has been deduced that the air temperature between the blow mold and the wall of the blown bottle has an impact on the kinetics of blowing the bottle.

A new method for preform dimension and influence of relevant parameters in the gear forced throughfeed rolling process

Gear rolling process is an advanced forming technology in which the rolling die extrudes the preform material to flow plastically and finally form desired gears, and the preform dimension has a decisive impact on the quality of the final formed gears. To further explore the influence of tooth-tip defects on the tooth height of the formed gears in the forced throughfeed rolling process, and ensure the quality of the formed parts, a new computational method for the preform dimension was firstly proposed. A growth coefficient model based on the effective top circle of the formed gears was also given. Then, the dependence of the effective top circle size in regard to geometric parameters and material of the formed gears such as the number of teeth, module, and pressure angle were explored by the established model and finite element analysis (FEA). Finally, the experimental results were displayed to verify the proposed computational method and theoretical model. The results show the growth coefficient increases with the increase of the number of teeth and module, and decreases as the pressure angle increases. Moreover, the material with better plastic deformation ability contributes to improving the growth coefficient. Additionally, the proposed new method and theoretical model for preform dimension calculation could be adopted in the gear rolling.

Analysis of thermal stabilization process for organomorphic preforms made of oxidized polyacrylonitrile

Simulation and analysis of thermophysical processes in PAN-fiber-based pressed samples that occurs during thermal stabilization were carried out. It is significant fact from the heat transfer point of view that the heat stabilization process proceeds with a definite exothermic effect. Herewith a strongly pronounced coupling between both the intensity of heat generation and the temperature level and heating rate at each point of the sample was observed. The influence of the main factors that effects on the sample temperature state, such as the density and thermal conductivity of the preform material, also the rate constants of the thermal stabilization process, was studied. The experimental data of the sample temperature state in the thermal stabilization process is presented and was compared with the analysis results.

Three-Dimensional Thermal Modeling and Management of System on Package with Gold and Nano Based Material

Abstract A detailed computational fluid dynamic based thermal model and simulation of exposed pad SOIC package on PCB is developed with Nano and gold-based material to characterize the thermal behavior or cooling capability of the package. Achieving lower thermal resistance of electronic packaging is one of the important points of interest in electronic application. In this paper, exposed small outline IC package on PCB is compared with different composition of Au-Sn die attach materials and Nano-foil preform material to understand the thermal behavior of the package which will provide cooling through low thermal resistance between junction-to-case. Thermal reliability of electronic packaging depends on the package design and selection of materials. Package material design plays an important role in thermal management of the product. Nano-based package material can be a good choice to improve the thermal performance of system on package. Developed a 3 D model of exposed small outline IC (E-SOIC) package on a printed circuit board (PCB). Au-Sn solder paste is used as die attach material and Nano-Foil preform is used to develop the system on package (SOP) model of exposed pad SOIC package on PWB. Different types of composition of Au-Sn solder paste, such as 78Au22Sn and 80Au20Sn are considered for die attach purpose. The reason for choosing the AuSn solder paste is good reliability and performance. Au-Sn has higher thermal conductivity than other solder materials, such as Pb-free solder paste, 96.5Sn3.5Ag and leaded solder paste, 37Pb63Sn. Two types of thermal model developed to compare the package material and design of the different die attach materials and Nano-Foil preforms. In this paper simulation and data analysis will show how the optimum thermal management depends on the material selection and design of the system on package (SOP). Surface mount type SOIC package with exposed pad design is selected to enhance the thermal purpose. Gold-tin and Nano-Foil preform will be used as alternative of lead-free package materials.

Analysis of non-equal-channel angular pressing scheme applied for obtaining magnesium sheet in cold state

Deformation patterns of rolling, equal-channel angular pressing and non-equal-channel angular pressing were evaluated. It is noted that when rolling, it is difficult to transfer a circular section preform into a rectangular section with a small thickness. This problem cannot be solved using equal-channel angular pressing. In connection with this, it is proposed to use a non-equal-channel angular pressing pattern to study the cast structure of magnesium. An experimental procedure based on cold extrusion of cylinders with a diameter of 42 mm and a height of 40 mm is described. The strip at the outlet was 40 mm in width and 1 mm in thickness. The percentage reduction of the preform material determined by the ratio of areas was 96 % with a draw ratio of 17. The specific pressures on the punch at the beginning ofthe extrusion process were 1200—1300 MPa, and extrusion force was 1670—1800 kN. The preform was cut into lengths that were rolled at a room temperature into 50 and 10 pm thick foils without intermediate annealing. Rolling was carried out on the Duo mill with a percentage reduction of 12—20 % at an average speed of 0,1 m/s. 20 passes were performed with a total relative reduction of 95 % to make the 50 pm thick foil. The results of computer simulation by the finite element method demonstrated that the constant value of the deformation degree is achieved at a rather considerable distance from the front end estimated as 50 times the thickness of the strip. The deformation rate field was calculated to determine the configuration of the deformation center. Energy costs were estimated. As a result of the completed set of calculated and experimental work, it was possible to establish the following — it is possible to produce a thin sheet preform from a cylindrical cast magnesium blank in one operation at a room temperature. The sheet blank has a level of ductility sufficient for subsequent sheet rolling. The sheet blank obtained in the proposed process has a high level of plastic deformation elaboration created due to the forming pattern with the high level of elongation and shear deformation. Despite the high level of pressure that must be applied to create a comprehensive compression scheme taking into account the lack of the need to heat the preform, energy costs are no higher than in traditional treatment processes.

Lithography Assisted Fiber-Drawing Nanomanufacturing.

We present a high-throughput and scalable technique for the production of metal nanowires embedded in glass fibres by taking advantage of thin film properties and patterning techniques commonly used in planar microfabrication. This hybrid process enables the fabrication of single nanowires and nanowire arrays encased in a preform material within a single fibre draw, providing an alternative to costly and time-consuming iterative fibre drawing. This method allows the combination of materials with different thermal properties to create functional optoelectronic nanostructures. As a proof of principle of the potential of this technique, centimetre long gold nanowires (bulk Tm = 1064 °C) embedded in silicate glass fibres (Tg = 567 °C) were drawn in a single step with high aspect ratios (>104); such nanowires can be released from the glass matrix and show relatively high electrical conductivity. Overall, this fabrication method could enable mass manufacturing of metallic nanowires for plasmonics and nonlinear optics applications, as well as the integration of functional multimaterial structures for completely fiberised optoelectronic devices.

Influence of Textile Reinforcement on Bending Properties and Impact Strength of SMC-components

In Europe, Sheet Molding Compound (SMC) has high market relevance in the field of glass fiber reinforced polymer composites with a market share of almost 20% in terms of mass. The material has a thermal expansion coefficient similar to steel and special grades show Class-A surface quality being thereby an appreciated material in the automotive industry. The mechanical properties of SMC components and thus its implementation in new application fields are mainly limited by the type of fiber and fiber length. The project “Preform-SMC” analyzed the combination of the standard SMC process (chopped long fibers) and the preform technology (textiles) in order to improve the overall performance of components. The studies revealed that the quality of the impregnation of the preform material is mainly determined by the density and thus the filler content of the SMC semi-finished product and the layer structure of the reinforcing fibers. Locally implemented reinforcing textiles improve, by implementing endless fibers among load paths, the mechanical properties. Depending on the fiber type and the layer structure e.g. impact strength and absorbed energy could at least be doubled.

Photogrammetric Surface Analysis of Ablation Processes in High-Enthalpy Air Plasma Flow

Results from an in situ analysis of ablative heat shield materials based on stereoscopic photogrammetry during plasma wind tunnel testing are presented. A carbon fiber preform material sample has been investigated in a high-enthalpy airflow corresponding to a Hayabusa reentry condition at a 78 km altitude. The applied photogrammetry uses two digital single lens reflex cameras triggered at to acquire images simultaneously from two different perspectives of the sample exposed to the high-speed flow. The photogrammetric analysis resolves the surface with , approximately 400 dpi, allowing the in situ analysis of the recession phenomena of ablators. Material inhomogeneities are identified during the ablation process, and surface recession is derived with an accuracy of . The method is a useful tool for the investigation of temporally resolved volumetric ablation phenomena in low-density carbon phenolic materials.

Electrical resistivity prediction of dry carbon fiber media as a function of thickness and fiber volume fraction combining empirical and analytical formulas

The transverse electrical resistivity of the dry unidirectional carbon fiber preforms was studied experimentally taking into consideration various parameters. The dependency of the electrical resistivity transverse to the fibers was thoroughly experimentally studied as a function of the preform thickness and the fiber volume fraction. Empirical mathematical relations were extracted and combined with a non-linear compaction semi-analytical formula. The extracted formula consolidates the compressibility of the preform material, the preform thickness and the fiber volume fraction or the applied pressure in order to calculate the electrical resistivity of the unidirectional preform material transverse to the fibers. Two electrical resistance measurements, at two different thicknesses and two electrical resistance measurements, at two different pressure levels, are necessary to obtained, in order to predict the full range of the electrical resistivity values of the preform material transverse to the fibers as a function of thickness and fiber volume fraction. Very good agreement between the proposed formulas and the experiments has been obtained.

Casting protocols for the production of open cell aluminum foams by the replication technique and the effect on porosity.

Metal foams are interesting materials from both a fundamental understanding and practical applications point of view. Uses have been proposed, and in many cases validated experimentally, for light weight or impact energy absorbing structures, as high surface area heat exchangers or electrodes, as implants to the body, and many more. Although great progress has been made in understanding their structure-properties relationships, the large number of different processing techniques, each producing material with different characteristics and structure, means that understanding of the individual effects of all aspects of structure is not complete. The replication process, where molten metal is infiltrated between grains of a removable preform material, allows a markedly high degree of control and has been used to good effect to elucidate some of these relationships. Nevertheless, the process has many steps that are dependent on individual "know-how", and this paper aims to provide a detailed description of all stages of one embodiment of this processing method, using materials and equipment that would be relatively easy to set up in a research environment. The goal of this protocol and its variants is to produce metal foams in an effective and simple way, giving the possibility to tailor the outcome of the samples by modifying certain steps within the process. By following this, open cell aluminum foams with pore sizes of 1-2.36 mm diameter and 61% to 77% porosity can be obtained.

Effects of flow forming parameters on the development of residual stresses in Cr–Mo–V steel tubes

Abstract Residual stress generation during flow forming tubular components of Cr–Mo–V ferritic steel has been studied in detail using laboratory X-ray and neutron diffraction. In the present work, flow formed tubes were available for a detailed parameter study including level of wall thickness reduction, starting hardness of the preform material, feed rate, and roller geometry. The high sensitivity of the residual stress distributions to the process parameters is showcased by selecting values within relatively short ranges. In general, low wall thickness reduction, low preform hardness, high feed rate, and rollers with a low contact angle were preferable for keeping stresses at a low level. Mohr׳s circle analysis was employed in order to determine the magnitude and direction of the principal stress, which were found to change depending on the combination of parameters. Finally, the level of stress mitigation by post-processing heat treatments was also characterised for selected samples.

Analysis of the post-filling phase of the vacuum-assisted resin transfer molding process

The vacuum-assisted resin transfer molding process uses a compliant vacuum bagging material which allows the thickness of the saturated preform to change as a function of pressure. The final thickness of the part is dependent on the post-filling phase where excess resin is bled from the preform to achieve a desired final part thickness. The flow of resin during the bleeding process is dependent on the compaction and permeability characteristics of the preform material. This paper examines the post-filling stage of the vacuum-assisted resin transfer molding process through finite element-based flow simulation and experimental studies. The studies focus on thick laminates where both in-plane and through thickness flows are considered. Comparisons of experimental and simulation results for two different post-filling scenarios provide insight into the post-filling phase of the vacuum-assisted resin transfer molding process including model validation as well as understanding of limitations of compaction/relaxation constitutive models in predicting final preform thickness.

Beam diameter dependence of surface damage threshold of fused silica fibers and preforms for nanosecond laser treatment at 1064 nm wavelength

Optical fibers made of fused silica are a common method of transmitting high laser pulse energies. Failure of those fibers is a significant risk. The determination of laser-induced damage thresholds (LIDT) on fiber end facets according to ISO 21254 standard is needed. In the past, single pulse nanosecond laser experiments showed an improvement of LIDT with increasing fiber core diameter for 1064nm wavelength and a constant beam diameter of 50μm.This paper pays particular attention to the influence of the laser beam diameter on damage resistance. All-silica fiber types (LEONI) with different core diameters (100–600μm) were investigated using beam diameters in a range from 30μm to 100μm. For comparison experiments on fused silica preform material (Heraeus F300) were performed. On one hand, surface LIDT of fused silica preform material decreases significantly with increasing beam size. A model considering a random distribution of point defects explains the experimental data qualitatively. On the other hand, LIDT of fiber end facets stays constant. White light microscopy results suggest that the point defect density on fiber end facets is lower compared to the preform surface due to an excellent surface polish quality.

Influence of mechanical stress on nanosecond laser-induced damage threshold of fused silica

Optical multimode fibers made of fused silica are widely used for transmission of high power laser pulses. Bending of fibers creates mechanical stress inside the material. The bend stress of a fiber can be calculated from bend radius, geometrical fiber parameters and Young's Modulus of the fiber core material and reaches typically values of 220MPa. A thermo-elastic model of Kusov et al. predicts a quadratic dependence of laser-induced damage threshold fluence with applied stress.In the present study, fiber preform material F300 (Heraeus) was loaded mechanically with pressures up to 220MPa representing 20% of the pressure resistance of fused silica. Bulk laser-induced damage thresholds (LIDT) were evaluated using a longitudinal multimode Q-switched Nd:YAG laser (1064nm) at a pulse duration of 12ns with polarization states parallel and perpendicular to the stress direction. LIDT of fused silica samples of about 700J/cm2 were found. LIDT did not show a dependence on mechanical pressure and polarization state which is a consequence of the small ratio of maximum applied stress (220MPa) to Young's Modulus of fused silica (72.5GPa).

Soft Magnetic Composite Switched Reluctance Generator - Fabrication and Analysis

The main objective of this paper is to investigate the suitability of Soft Magnetic Composite (SMC) material SOMOLOY1000 for a Switched Reluctance Generator (SRG) through electromagnetic, thermal and vibration characteristics employing extensive Finite Element Analysis. The fabrication aspects of Soft Magnetic Composite Switched Reluctance Generator (SMC-SRG) using preform material blanks utilizing indigenous machining process have been delineated. The static and transient electromagnetic characteristics have been obtained through the electromagnetic finite element analysis software MagNet6.22.1 while the thermal and vibration aspects have been studied through coupled field Finite Element Analysis employing the multi physics software ANSYS10 while the Impulse hammers excitation - free vibration test using RT Pro Photon data acquisition system facilitated the experimental determination of vibration characteristics. The study concludes that the advantages of less weight , low torque ripple, low eddy current losses, reduction in vibration level of stator structure coupled with the ability to maintain precise mechanical dimensional tolerance may present SMC-SRG a viable candidate in standalone wind energy conversion systems meant for rural and remote area electrification scheme.

Breakdown limits of optical multimode fibers for the application of nanosecond laser pulses at 532 nm and 1064 nm wavelength

For many applications, optical multimode fibers are used for the transmission of powerful laser radiation. High light throughput and damage resistance are desirable. Laser-induced breakdown at the end faces of fibers can limit their performance. Therefore, the determination of laser-induced damage thresholds (LIDT) at the surface of fibers is essential. Nanosecond (1064 nm and 532 nm wavelength) single-shot LIDT were measured according to the relevant standard on SiO 2 glass preforms (Suprasil F300) as basic materials of the corresponding fibers. For 10 kinds of fused silica fibers (FiberTech) with core diameters between 180 μm and 600 μm, an illumination approach utilizing a stepwise increase of the laser fluence on a single spot was used. For both wavelengths, the LIDT values (0% damage probability) obtained by means of the two methods were compared. The influence of surface preparation (polishing) on damage resistance was investigated. For equal surface finishing, a correlation between drawing speed of the fibers and their surface LIDT values was found. In addition to the surface measurements, bulk LIDT were determined for the preform material.