Glass Manufacturing Process Research Articles

A novel industrial process situation awareness model based on multi‐time scale dynamic feature fusion with applications to float glass manufacturing

AbstractModern industrial manufacturing processes often focus on the changes of performance indicators and the evolution of operation conditions. However, the dynamics of variables are vague within processes and even more difficult to be characterised across different processes. The time‐series dynamic characteristics of the different scales among variables, processes, and production cycles develop and transfer with changes in parameters, equipment, and processes. It is difficult to accurately show the quality index and operating condition trend at the same time. To solve these problems, a situation awareness (SA) framework integrating multi‐time scale dynamic features for manufacturing processes is proposed. First, data are condensed and reconstructed through the denoising long short term memory autoencoder to reveal the time series dynamic characteristics to get neighbourhood features which contain features among neighbourhood samples. Second, the neighbourhood features divided into window blocks are fused into the stage features by statistical analysis. Finally, a multi‐scale isometric convolution network is designed to extract the local and global features, which can effectively show the development of dynamic features on a long time scale, and profoundly describe the influence of full cycle features on variables and operating conditions. The proposed model is verified on the real data set of a float glass manufacturing process, and the SA model can well predict the future trend of long time series.

Effect of ammonia-air combustion melting on the color and physical properties of soda lime silicate

Ammonia is a carbon-free fuel; hence, it does not generate CO2 during combustion. However, ammonia has a different combustion reaction and flue gas composition from conventional city gas; therefore, its impact on the glass-melting process and glass quality is unknown. In this study, batches of soda lime silicate glass and cullet raw materials were melted using ammonia or city gas as the fuel. Furthermore, the glass melted in the combustion and exhaust gas fields was analyzed to evaluate the effects on composition and color tone. The type of fuel and combustion atmosphere were found to affect the color and glass transition temperature. The batches and cullet materials that melted in the combustion field were colored because of combustion-atmosphere-induced changes in the valence of the Fe in the raw materials, and the coloration of this glass was more affected by the cullet than by the batches. Meanwhile, the glass melted in the exhaust gas field of ammonia combustion exhibited a lower glass transition temperature owing to the higher presence of H2O in the exhaust gas. The temperature was measured by four thermocouples (TC1–4) installed inside the furnace. The glass transition temperature of the glass at the TC4 position in the exhaust gas field using ammonia as fuel was 24 and 9 °C lower than those of the reference batch and cullet, respectively. Ammonia can be used as a decarbonized fuel for glass-melting furnaces by designing raw materials for soda lime silicate glass. However, the raw materials containing carbonates emitted CO2 in the exhaust gases during ammonia combustion. Therefore, to achieve a carbon-neutral glass manufacturing process, CO2 derived from both raw materials and fuel should be reduced.

Tree-based machine learning approach to modelling tensile strength retention of Fibre Reinforced Polymer composites exposed to elevated temperatures

Fibre Reinforced Polymer (FRP) composites are susceptible to degradation at elevated temperatures. Accurate modelling of the tensile performance of FRP composites under high-temperature exposure is crucial for their structural integrity. In this study, tree-based models, namely, decision tree, M5P, and random forest methods, are utilised to model the impact of elevated temperatures on the tensile strength of composite materials. A database of 787 experimental results is established and processed to train and test the regression tree models. The exposure temperature, resin glass transition temperature, sample thickness/diameter, exposure duration, ambient cooling, fibre-to-resin ratio, fibre orientation, resin type, fibre type, and manufacturing process were considered as the main parameters affecting the tensile strength retention (TSR) of FRP composites after exposure to elevated temperatures. To improve the prediction performance of machine learning, Bayesian optimisation and 10-fold cross validation (CV) technique were used to train regression tree methods. The results demonstrated the accuracy of the developed models in predicting the TSR of the composites under elevated temperatures. Feature contribution analysis showed that the exposure temperature exerts the most significant impact on the TSR, with the glass transition temperature coming next in importance. These were followed by sample thickness, exposure duration, ambient cooling, fibre-to-resin ratio, and fibre orientation, respectively. Resin type, fibre type, and the manufacturing process had the least contributions to the observed variations in TSR. Examining the tensile strength retention of FRP composites at high temperatures enables the development of precise predictive models and design guidelines for their optimal use across industries.

Detailed comparison of physical fining methods in an industrial glass melting furnace using coupled CFD simulations

Melting and primary fining represent the most essential steps in the glass manufacturing process. Electric boosting and bubbling are common methods used to optimize these processes by improving the product quality and energy efficiency. However, a structured overview of their impacts on the operation of the total melting furnace has not previously been published. The present paper provides a thorough comparison of these technologies applied to an industrial melting furnace, including the effects on temperatures, melt flow patterns, glass quality, as well as the heat fluxes and process efficiency. In this work, extensive numerical simulations were performed. Unlike other studies described in the literature, a validated CFD model of exceptionally high accuracy was employed. Furthermore, the entire melting furnace was considered, such that the glass tank was coupled to detailed simulations of the turbulent gas-phase combustion. A novel method for combustion modeling in glass manufacturing was applied, and user-defined functions supported an analysis of glass quality. Substantial differences were observed between the furnaces with electric boosting and bubbling. For the first time, interrelated effects could be described in detail, providing a comprehensive overview of the entire operation. Based on the presented results, the targeted use of both electrodes and gas nozzles is suggested for future melting processes.

Optical Design of a Miniaturized 10× Periscope Zoom Lens for Smartphones.

The size of the optical zoom system is important in smartphone camera design, especially as it governs the thickness of the smartphone. We present the optical design of a miniaturized 10× periscope zoom lens for smartphones. To achieve the desired level of miniaturization, the conventional zoom lens can be replaced with a periscope zoom lens. In addition to this change in the optical design, the quality of the optical glass, which also affects the performance of the lens, must be considered. With advancements in the optical glass manufacturing process, aspheric lenses are becoming more widely used. In this study, aspheric lenses are incorporated into a design for a 10× optical zoom lens with a lens thickness of less than 6.5 mm and an eight-megapixel image sensor. Furthermore, tolerance analysis is carried out to prove its manufacturability.

The analysis of glass from portable electronic devices and glass accessories using µ-XRF for forensic investigations

In this study, glass from 30 different portable electronic devices (PED) screens, 15 screen protectors (SP), and 3 brands of liquid glass (LG) were analyzed using a µ-XRF instrument equipped with two silicon drift detectors (SDD). Additional analysis of six fragments, all originating from the same PED and SP screen, assessed the elemental homogeneity within a single glass source. Examinations of the 30 PEDs and the majority of the SP screens revealed spectra with low sodium and high potassium, which is likely due to the ion exchange process at the surface during the glass manufacturing process. The absence of calcium in the XRF spectra was also characteristic of PED formulations. Initial spectral overlay examinations classified the PED and SP samples into major groups based on their distinctive elemental profiles (5 PED groups, 4 SP groups). Further discrimination of within-group samples was possible when considering reproducible differences in signal intensities (discrimination 98.4 % PED, 98.1 % SP). Additionally, a 3 s (3 % Relative Standard Deviation, RSD) comparison criterion produced the lowest false exclusion rates among same-source fragments (3.3 % PED, 0.8 % SP) while maintaining a high discrimination power among different-source fragments (98.4 % PED, 100 % SP). Same source PED and SP samples resulted in low variability within most elements examined (< 8 % RSD), except for potassium. An experimental threshold established from the quantitative metric of spectral similarity, spectral contrast angle (SCA) ratio of same-source and different-source datasets, produced false exclusion and false inclusion rates of 4 % or 0.95 % for PED and SP fragments, respectively. Spectra of just the liquid glass residues indicated some major elements present but the effect of these elements in PED fragments treated with liquid glass was not significant. This study provides a preliminary understanding of the elemental composition of modern PED glasses and their accessories and the discrimination capability of µ-XRF for forensic comparisons.

Energy saving properties and development products of low radiation glass

With the development of modern society, more and more buildings have appeared, and the problem of building energy consumption has also attracted people's attention. The problem of building energy consumption really needs to be solved. It needs to work together from many aspects to reduce energy consumption, including the use of energy-saving glass. This article analyzes and summarizes the existing literature on energy-saving glass to explain the energy-saving principle and manufacturing process of low radiation glass in detail. The method of data analysis is adopted to compare the energy-saving effect of different energy-saving glasses based on the existing data, and the energy-saving effect of low radiation glass is objectively analyzed. The research found that the low radiation glass has strong heat insulation ability and heat preservation effect, and has significant energy saving effect, which is very suitable for the concept of energy-saving buildings in contemporary society.

Fabrication of Color Glass by Pearlescent Pigments and Dissolved EVA Film.

In this paper, we propose a single-layer thin-film color glass manufacturing process for building-integrated photovoltaics (BIPV) with excellent aesthetics and high transmittance, through a solution process using pearlescent pigments. As a matrix for the color solution, ethylene vinyl acetate (EVA), which serves as an encapsulant and adhesive for the photovoltaic module (PV), was dissolved and used as a matrix for the color solution. The color glass produced is excellent in securing the aesthetics of buildings, has a high transmittance of 90% or more, outputs a maximum solar power generation efficiency of 91% from a solar cell, and can minimize the deterioration of power generation efficiency. In addition, the characteristics do not change over time, so it is suitable as color glass for BIPV. Through this study, the solution-based color glass manufacturing process for BIPV using dissolved EVA as a matrix forms a single-layer thin film with good color extensions. The choice of EVA as a matrix makes it possible for color glass to be easily attached to a solar panel using a heat press method. This proposed technique makes it easier and simpler to manufacture color glass as compared to the physical vapor deposition process. The adoption of this solution process technique to fabricate pearlescent pigment-based color glass can effectively reduce the time and cost of the process, so it is expected to be applied to the low-cost BIPV market with excellent aesthetics and high transmittance.

Characterization of oxyfluorotellurite glasses with TeO2–Li2O–ZnO–LiF composition

Oxyfluorotellurite glasses in the form of 60TeO 2 –(15–x)Li 2 O–25ZnO–xLiF, 65TeO 2 –(15–x)Li 2 O–20ZnO–xLiF (with x = 0, 5, 10, and 15 in mol %), and 65TeO 2 (20–x)Li 2 O–15ZnO–xLiF (x = 0, 5, 10, 15, and 20 in mol %) have been synthesized. The amorphous state of the samples was assessed using X-ray diffraction (XRD). Density, molar volume, and oxygen packing density (OPD) were measured. The thermal properties were analyzed from room temperature to 873 K using a differential scanning calorimeter (DSC). The structural and optical properties were investigated using Fourier-transform infrared (FTIR), Raman, and ultraviolet–visible (UV–Vis) spectroscopies. The results demonstrated that the OPD values decreased with increasing LiF content, and this decrease can be attributed to a decrease in the total oxygen number. The structural characterization revealed that the addition of LiF reinforces the vitreous network causing the formation of F–Te–O bonds within a more connected network. In addition, increasing the LiF content improved the glass’s thermal properties, with a decrease in the glass transition temperature and an increase in thermal stability, which facilitates the glass manufacturing process. However, this feature is dependent on ZnO concentration.

Overview of 3D-Printed Silica Glass.

Not satisfied with the current stage of the extensive research on 3D printing technology for polymers and metals, researchers are searching for more innovative 3D printing technologies for glass fabrication in what has become the latest trend of interest. The traditional glass manufacturing process requires complex high-temperature melting and casting processes, which presents a great challenge to the fabrication of arbitrarily complex glass devices. The emergence of 3D printing technology provides a good solution. This paper reviews the recent advances in glass 3D printing, describes the history and development of related technologies, and lists popular applications of 3D printing for glass preparation. This review compares the advantages and disadvantages of various processing methods, summarizes the problems encountered in the process of technology application, and proposes the corresponding solutions to select the most appropriate preparation method in practical applications. The application of additive manufacturing in glass fabrication is in its infancy but has great potential. Based on this view, the methods for glass preparation with 3D printing technology are expected to achieve both high-speed and high-precision fabrication.

The product-mold-machine manufacturing problem

This paper introduces the product-mold-machine manufacturing problem, which is related to the manufacturing process of tires, plastics, ceramics, and glass. Each product has its own shape and mechanical properties obtained from processing a specific mold on a machine. Each machine can process a set of molds at the same time and, hence, the processing time on a machine depends on the longest processing time among the set of molds on the machine. The objective is to find a production plan that minimizes the total number of periods needed to meet the demand of each product, considering a limited number of machines, molds, changeover times, and incompatibilities constraints. We provide a mixed integer linear programming model for the problem and propose two constructive heuristics of polynomial-time, which provide upper bounds on the optimal value and easy-to-implement feasible solutions. Numerical experiments carried out over instances based on real data show the effectiveness of the proposed approaches.

Energy and Material Flow Evaluation with CO2 Emissions in the Glass Production Process

Glass manufacturing is an energy-intensive process with high demands on product quality. The wide usage of glass products results in a high end-product diversity. In the past, many models have been developed to optimize specific process steps, such as glass melting or glass forming. This approach presents a tool for the modeling of the entire glass manufacturing process for container glass, flat glass, and glass fibers. The tool considers detailed bottom-up energy and material balance in each step of the processing route with the corresponding costs and CO2 emissions. Subsequently, it provides the possibility to quantify optimization scenarios in the entire glass manufacturing process in terms of energy, material and cost flow efficiency.

A robust multivariate Shewhart chart for contaminated normal environments

AbstractLately, the multivariate setup of control charts, especially the memory‐less chart has received less attention of researchers as compared to the univariate setup. However, the multivariate setup is of paramount importance in this big‐data era. In this research work, we study the multivariate Shewhart chart for monitoring location parameter by examining the robustness of this scheme with the mean estimator. We also explored the scheme with some other robust parametric estimators in different process environments. The multivariate estimators such as median, midrange, tri‐mean (TM), and Hodges–Lehmann (HL) estimators were examined under uncontaminated, location contaminated, variance contaminated, and both location–variance contaminated normal environments. Through a synthetic Monte Carlo simulation and application of the schemes on a real‐life dataset, the findings suggest that the proposed estimators outperform the default estimator of the multivariate scheme (mean). The performance measures of comparing these estimators through the charts are the average run length, standard deviation run length, extra‐quadratic loss, and relative average run length. The charts resulting from applying the schemes on real‐life dataset recorded from glass manufacturing process also buttresses the simulation findings.

Mathematical models for a cutting problem in the glass manufacturing industry

The glass cutting problem proposed for the ROADEF 2018 challenge is a two-dimensional, three-stage guillotine cutting process, with an additional cut to obtain pieces in some specific situations. However, it is not a standard problem because it includes specific constraints. The sheets produced in the glass manufacturing process have defects that make them different and have to be used in order. The pieces to be cut are grouped into subsets and the pieces from each subset must be cut in order.We approach the problem by developing and solving integer linear models. We start with the basic model, which includes the essential features of the problem, as a classical three-stage cutting problem. Then, we progressively add new conditions to consider the order in the stacks, the minimum waste produced by guillotine cuts, and the possibility of trimming in some specific cases. Finally, we deal with the existence of defects in the sheets. We propose the first integer linear model capable of working with trimming and defects. The results show that in most cases it is possible to obtain the optimal solution for small problems taking into account all the constraints of the real problem and that good feasible solutions are obtained for larger instances.

Experimental Use of Microwaves in the High Temperature Foaming Process of Glass Waste to Manufacture Heat Insulating Material in Building Construction

&#x0D; &#x0D; &#x0D; &#x0D; Abstract &#x0D; The aim of the paper was the experimental manufacture of cellular glass from glass waste and coal ash as raw material and silicon carbide as a foaming agent, using the unconventional microwave heating technique. This heating technique, although known since the last century and recognized worldwide as fast and economical, is not yet industrially applied in high temperature thermal processes. The cellular glass manufacturing process requires high temperatures and the use of microwaves in this process is the originality of the work. The experiments aimed at producing thermal insulating materials with high porosity and low thermal conductivity for building construction similar in terms of quality to those manufactured industrially by conventional techniques, but with lower energy consumption. The obtained samples had adequate characteristics (apparent density 0.22-0.32 g/cm3, porosity 85.5-90.0%, thermal conductivity 0.043-0.060 W/m·K, compressive strength 1.23-1.34 MPa), and the specific energy consumption was low (0.84-0.89 kWh/kg). Theoretically, given the use of microwave equipment on an industrial scale, this consumption comparable in value to that industrially achieved by conventional techniques could decrease by up to 25%.&#x0D; &#x0D; &#x0D; &#x0D;

Tungsten DiSulphide FBG Sensor for Temperature Monitoring in Float Glass Manufacturing

In this paper, a temperature monitoring system for glass manufacturing process is proposed by using Fibre Bragg Grating (FBG) approach. This system can be done by using OptiSystem simulation. FBG was used as it allows a reflects a wavelength of light that shifts according to variations in temperature. Generally, FBG sensors can be easily installed, it has higher accuracy, longer stability, small in size, immunity to electromagnetic interference (EMI) and the ability to measure ultra-high and speed events. The results indicated that wavelength shifting is depended on thermal expansion coefficient and thermo-optic coefficient of materials, from simulation results it was seen that, Tungsten DiSulfide(WS2) has a better sensitivity than Silica, Poly Methyl Methacrylate(PMMA) and Lead Sulfide(PbS).

Nanostructure characteristics of Bi2O3:Al2O3 thin films and the annealing temperature effect on morphological, optical, and mechanical properties

In this work, Bi2O3:Al2O3 thin films were prepared on a glass substrate by pulsed laser deposition (PLD) then thermally treated by annealing at temperatures 300, 400, and 500 °C. XRD analysis reveals that all films have a polycrystalline structure of Bi2Al4O9 with the presence of secondary phases of Bi2O3 and Al2O3, the degree of crystallinity increased with annealing temperature, we observed a significant decrease in crystallite size after annealing. SEM and AFM measurements show the films are homogeneous and free of voids and cracks with spherical nanoparticles and relatively high roughness. The optical characteristics show a redshift in the bandgap with increasing annealing temperature. Vickers micro-hardness increased with annealing temperature, the optimum condition is recorded in the films annealed at 500 °C where the highest micro-hardness is recorded and found to be comparable to those of soda-lime glass. These characteristics prove this composite is a promising material in the glass manufacturing process, optoelectronics, and smart windows.

Optimal demand response operation of electric boosting glass furnaces

The glass industry is highly energy-intensive, accounting for 1% of total industrial energy consumption in the United States. Most of the energy consumption in the glass manufacturing process is attributable to the significant heat required to melt raw materials. An electric boosting system which can transfer extra heat (5%–20% of total energy) to the glass melt in addition to the energy from natural gas combustion can be implemented in a glass furnace. Electric boosting is thermally efficient, reduces direct pollutant emissions, and prolongs furnace superstructure lifespan. However, a high level of electric boost is not always economically desirable, considering the volatility of electricity prices. Balancing between natural gas and electricity consumption in a demand response strategy can reduce the energy cost and mitigate strain on the electrical grid. In this paper, a physics-based model is developed to describe the dynamic behavior of a prototype electric boosting glass furnace. We present a dynamic optimization strategy to optimally balance between using natural gas and electric power under electricity price fluctuations. Case studies on the effect of varying energy prices and emissions regulations are analyzed.

Roasting of pyrophyllite for application in aluminoborosilicate glass production

ABSTRACT Pyrophyllite, an aluminum silicate mineral, was used as a raw material for the production of aluminoborosilicate glass. For the application of pyrophyllite to the glass manufacturing process as a raw material, the particle size distribution of the powder must the following requirements: 150–45 μm ≥ 60 mass% and below 45 μm ≤ 40 mass%. Hence, an attempt was made to develop the technology for pyrophyllite to produce a powder that meets these requirements through understanding the crushing characteristics. Roasting of pyrophyllite at 1150 °C resulted in the alternation of raw pyrophyllite and led to differences in the crushing characteristics. Crushing of the roasted pyrophyllite produced a powder with a reduction in the amount of the fine particles (−45 μm) compared to the powder of the raw pyrophyllite under identical crushing condition. This difference is attributed to the alternation of the raw pyrophyllite after the roasting process, as confirmed by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) results as well as by the amount of water adsorption. The melting characteristics of the raw and roasted pyrophyllite samples were investigated for application to the aluminumborosilicate glass production. The glass products are characterized as colorless and in an amorphous phase.

Manufacture of Glass Foam by Predominantly Direct Microwave Heating of Recycled Glass Waste

The paper presents authors’ contribution to the improvement of the manufacturing technique of foam glass using the microwave energy. Due to the physical and mechanical characteristics, this material, obtained by the sintering process of waste glass at high temperature, constitutes a viable replacer of existing similar materials, used especially in construction. Unlike the conventional heating methods used worldwide, the company Daily Sourcing &amp; Research SRL Bucharest tested lately microwave heating techniques in the manufacturing process of foam glass. In the paper it is presented an original method based on the feature of the powder mixture composed by waste glass (over 97 wt.%) and the foaming agent (calcium carbonate) to absorb the microwave energy and convert it to heat since the ambient temperature, using a silicon carbide and silicon nitride (80/ 20 weight ratio) crucible with thin wall (2.5 mm), which allows both a preponderantly direct heating and partially an indirect heating of the material. The main parameters of the process (specific consumption of energy, heating speed, process temperature and duration) were significant improved compared to the previous experiments.