Glass-molding Machines Research Articles

Surface failure analysis of AlCrN coating on WC substrate subjected to high-temperature oxidation in glass-molding machine

In this study, a surface failure analysis was performed on an aluminum chromium nitride (AlCrN) coating formed on a tungsten carbide (WC) substrate used in a glass-molding machine and subjected to oxidation at elevated temperatures. Several pinholes were observed in the coating, with the coating surface exhibiting discoloring. The microstructures, crystalline structures, and elemental compositions of the coating and substrate were observed using scanning electron microscopy, X-ray diffraction analysis, and X-ray fluorescence spectroscopy. In particular, the phenomena occurring near the coating/substrate interface were examined using focused ion beam milling and grazing incidence X-ray diffraction analysis. The pinholes-containing coating area consisted of an oxide, with the composition of the coating being inhomogeneous. Further, voids were present near the substrate/coating interface, with some of the coating components being detected in the substrate as well. It was concluded that the Al/Cr atomic ratio of the AlCrN coating was not constant, owing to the oxidation of the coating at the elevated temperatures.

모바일 스마트 기기 덮개 유리 순차이송형 성형기기의 가열시스템 최적화에 관한 연구

ABSTRACT Nowadays, flat-shaped cover glass is widely used for mobile devices. However, for its good design and convenience of use, curved cover glass has been demanded. Thus, many companies have tried to produce curved cover glass through the shaving technique, but the production efficiency is very low. Therefore, the molding technique has been adopted to increase the efficiency for the curved-glass production system. For a glass-molding system, several heating blocks are installed, and the flat cover glass is sequentially heated and molded. The production time for the cover glass is very different depending on the heating conditions; thus, the prediction of the production time for different heating conditions should be needed. Therefore, in this study, the computations were performed with different heating conditions (uniform and non-uniform) in the present cover glass-molding machine. For uniform and non-uniform heating conditions, the simple correlation between the heating time and the heater capacity and the heating time to achieve higher durability can be suggested, respectively.KeyWords : Glass Molding System(유리 성형 시스템), Thermal Analysis( ), Heating Time( )열해석 가열시간

Mechanical Properties of Pt-Ir and Ni-Ir Binary Alloys for Glass-Molding Dies Coating

In this study, the different compositions of Pt-Ir and Ni-Ir alloys were deposited by utilizing ion source assisted magnetron sputtering system (ISAMSS). The surface roughness and crystallite size of the Pt-Ir and Ni-Ir coatings were analyzed by atomic force microscopy (AFM) and X-ray diffraction (XRD), respectively. In addition, coatings were soaked at 700 degrees and maintained 10 min under N2 atmosphere using a glass-molding machine. The annealed coatings for oxidation test were examined by energy dispersive X-ray spectrometry (EDS) and for microhardness and reduced modulus test were evaluated by nanoindentation instrucment. The cross-sectional structures between the Pt-Ir and Ni-Ir coating layer and substrates were also examined by field emission scanning electron microscope (FESEM). The results show that surface roughness Ra from 1.25 nm to 3.426 nm was observed with increasing the Ni elements. However, the Ra is less than 2 nm measured in Ir-based coatings doped with Pt concentrations under this study. With increasing Pt and Ni doping, the microhardness of both coatings decreased significantly and the values of reduced modulus of Pt-Ir alloys are larger than that of Ni-Ir alloys. After oxidation process, the oxygen concentration of Pt-Ir coatings is less than that of Ni-Ir coatings and the Pt-Ir coatings exhibit superior properties including oxidation resistance, low surface roughness and high reduced modulus over Ni-Ir coatings, especially for the high Pt concentration coatings such as Pt-Ir 2 (55.25 at.% Pt) and Pt-Ir 3 (79.42 at.% Pt) coatings. The surface roughnesses of all specimens annealed at 700 degrees C were slightly larger than as-deposited coatings. Moreover, due to the serious oxidation occurred in Ni-Ir 3 (73.45 at.% Ni) coatings, the value of reduced modulus of this specimen coating is the lowest and the corrsponding Ra value is the largest compared with the rest of Ir-based coatings in the oxidation testing.

A new fire- and explosion-proof lubricant for glass-shaping molds

Compositions and properties of a new lubricant for glass-shaping molds and glass-molding machines are given. Its advantages over existing lubricants based on colloidal-graphite mixtures are shown.

The effect of the parameters of the molding unit in glass-molding machines on the nonstationary temperature field of glass molds

The temperature field of glass molds in the case of their external cooling is considered. The temperature field is represented as a sum of two components: the stationary component not depending on time, and the component cyclically varying with time. The cyclic component is investigated for the case where the heat flows at the mold boundaries are harmonic functions of time. Ratios establishing the relationship between the mold temperature variations per cycle and the molding unit parameters, as well as the relationships between the optimum values of these parameters, are obtained. The amplitude of temperature variations on the mold working surface is calculated for different parameters of the molding unit.

Heat regimes for the operation of automatic glass-molding machines

Heat regimes for the operation of automatic glass-molding machines

Selecting the optimum glass-gob temperature in the production of glassware on automatic glass-molding machines

Selecting the optimum glass-gob temperature in the production of glassware on automatic glass-molding machines

Feeders for glass-molding machines with combined electric heating

Feeders with combined electric heating have several advantages over feeders operated on liquid or gas fuel: more economical and convenient to use; increase of the thermal uniformity of the glass; and the ability to reduce the temperature gradient 2-4 fold. The authors attempt to obtain a solution by an electroheat analog using a BUSE-70 electrointegrator. The solution of the problem on an electro-integrator made it possible to reach another conclusion--if the electrodes are switched off and the upper heaters are operated at a load of 14 kW per meter of feeder length, the temperature in the cross section of the flow of glass is distributed as follows: in the center layers, 1020 degrees C; in the peripheral, 960 degrees C. Using a physical and analog model, the optimal relationship between the power in feeders with combined electric heating can be established. The results of this study can be used in planning electrically heated feeders and adjusting their operational regimes.

Automatic control of the mass of the gob on PVM glass-molding machines

Automatic control of the mass of the gob on PVM glass-molding machines

Optimum mass for cast-iron molds in the AV-type glass-molding machines

Optimum mass for cast-iron molds in the AV-type glass-molding machines

Technological lubricants for the molds of glass-molding machines

Technological lubricants for the molds of glass-molding machines

Untapped reserves for increasing the productivity of glass-molding machines

Untapped reserves for increasing the productivity of glass-molding machines

Organization of the repair and replacement of automatic glass-molding machines

Organization of the repair and replacement of automatic glass-molding machines