Glass Press Research Articles

Removal of collagen three-dimensional scaffold bubbles utilizing a vacuum suction technique.

The process of generating type I/II collagen scaffolds is fraught with bubble formation, which can interfere with the three-dimensional structure of the scaffold. Herein, we applied low-temperature vacuum freeze-drying to remove mixed air bubbles under negative pressure. Type I and II rubber sponges were acid-solubilized via acid lysis and enzymolysis. Thereafter, vacuum negative pressure was applied to remove bubbles, and the cover glass press method was applied to shape the type I/II original scaffold. Vacuum negative pressure was applied for a second time to remove any residual bubbles. Subsequent application of carbamide/N-hydroxysuccinimide cross-linked the scaffold. The traditional method was used as the control group. The structure and number of residual bubbles and pore sizes of the two scaffolds were compared. Based on the relationship between the pressure and the number of residual bubbles, a curve was created, and the time of ice formation was calculated. The bubble content of the experimental group was significantly lower than that of the control group (P < 0.05). The pore diameter of the type I/II collagen scaffold was higher in the experimental group than in the control group. The time of icing effect of type I and II collagen solution was 136.54 ± 5.26 and 144.40 ± 6.45s, respectively. The experimental scaffold had a more regular structure with actively proliferating chondrocytes that possessed adherent pseudopodia. The findings indicated that the vacuum negative pressure method did not affect the physical or chemical properties of collagen, and these scaffolds exhibited good biocompatibility with chondrocytes.

A Study on Ball Motion Control Method for Glass Press Handling Based on Plate Manipulation of Industrial Dual Arm Robot

A Study on Ball Motion Control Method for Glass Press Handling Based on Plate Manipulation of Industrial Dual Arm Robot

AE法を併用した静的および繰返しインデンテーション試験による高温環境下でのDLC膜の強度評価

This study aims to evaluate strength of a diamond-like carbon (DLC) film on a metal for glass press molding at high temperature. Static and cyclic indentation tests at high temperature up to 300℃ with AE monitoring technique were performed. AE monitoring reveled crack generation load or cyclic number during the indentation tests. The static strength of the films at each temperature was determined from maximum stress in the film in the radial direction induced by sink-in deformation due to static indentation. The maximum stress at each temperature was estimated with indentation loads at first AE generation and FEM analysis. Thermal stress in DLC film was at each temperature also calculated. The film strength estimated by taking the thermal stresses into account was decreased with an increase of temperature. In cyclic indentation test, AE due to cracks in film was detected after 1.0×104 cycles at the load where no crack generated under one loading cycle. The cyclic number to crack initiation for the sample in 300℃ was 1/50 smaller than that in room temperature.

熱衝撃試験による金型離型用DLC膜の損傷評価

This study aims to evaluate adhesion quality and surface damage of DLC film as a releasing agent with a thermal shock test. To imitate a practical glass press molding process, DLC specimen was vacuum-encapsulated with a glass tube, and then they were heated up to 610oC using the electric furnace and were quenched to 20oC in water. After eight cycle thermal shock test, localized surface damage and exfoliations were observed, and expanded with the cyclic number. Moreover, the ratio of G-peak to D-peak (ID/IG) in Raman spectra suggesting the degree of graphitization of DLC for the samples after the test increased. These results show that the proposed thermal shock test is useful to evaluate the adhesion quality and surface damage of the DLC film at high temperature.

Feasibility study on cubic boron nitride coated glass press molds

We report the feasibility of glass press molds using high-quality, thick cubic boron nitride (cBN) films prepared in a plasma jet by chemical vapor deposition. A press test using a cBN film for an optical glass is carried out at a high temperature (≥ 650 °C), above the glass transition temperature. Surface morphology, chemical composition, and optical transparency of the glass after a press test are examined by atomic force microscopy, X-ray photoelectron spectroscopy, energy dispersion X-ray spectroscopy, and ultraviolet-visible-near-infrared (UV-VIS-near-IR) and IR spectroscopy. The B and N concentrations at the top several nanometers of the glass increase by several at.% after a press test. This is attributed to diffusion of B and N from the film into the glass. The UV-VIS-near-IR transparency of the glass in a short wavelength range (≤ 900 nm) decreases by several % due to light scattering at the roughened glass surface. In contrast, the IR transparency of the glass remains constant despite an increase in the surface roughness.

Micro/nano electro mechanical systems for practical applications

Silicon MEMS as electrostatically levitated rotational gyroscope, 2D optical scanner and wafer level packaged devices as integrated capacitive pressure sensor and MEMS switch are described. MEMS which use non-silicon materials as diamond, PZT, conductive polymer, CNT (carbon nano tube), LTCC with electrical feedthrough, SiC (silicon carbide) and LiNbO3 for multi-probe data storage, multi-column electron beam lithography system, probe card for wafer-level burn-in test, mould for glass press moulding and SAW wireless passive sensor respectively are also described.

RECENT PROGRESSES OF APPLICATION-ORIENTED MEMS THROUGH INDUSTRY-UNIVERSITY COLLABORATION

MEMS research has been carried out through industry-university (Tohoku) collaboration for practical applications. Sophisticated devices such as electrostatically levitated rotational gyroscope, MEMS relay for wafer level packaging, array MEMS including multi-probe data storage and multi-column electron beam lithography system, small diameter fiber optic pressure sensor and SiC micro structure or glass press molding, have been developed. Electrical feedthroughs in glass play important role in the wafer level packaging and array MEMS. Materials such as conductive polymer for recording media, carbon nanotube for electron field emitter, SiC for harsh environment are used in these MEMS because of their unique features.

Development of Ultrasonic Vibration Assisted Polishing Machine for Micro Aspheric Die and Mold

Demands are increasing for micro axis-symmetric aspherical lenses to be installed in various optical devices. The micro glass lenses are generally molded by glass press process with micro aspheric ceramic molding dies or molds made of tungsten carbide or silicon carbide. These dies and molds are mostly ground with micro diamond wheels, but require additional finishing process as the size of the dies and molds become smaller and the required accuracy becomes higher. In order to finish micro aspheric dies and molds with diameter less than 3mm, an ultrasonic vibration assisted polishing machine is developed. A small polishing tool is mounted on a 3-axis controlled table, and vibrated at an ultrasonic frequency with piezo-electric actuators. The polishing pressure can be controlled with a resolution of 2 mN. Some micro aspheric molding dies made of binder-less tungsten carbide were polished, and the form accuracy below 70 nmP-V and surface roughness of 7 nmRy were obtained with the developed machine.

Camphor cryoscopy by differential thermal analysis

The determination of the freezing point depression of organic solutions with camphor as solvent was performed by means of DTA. Amounts of 50–100μg substance and 1–2 mg camphor were weighed on a platinum wire, the camphor being pressed to a pellet by a glass press. The temperature difference between the glass tubes with pure camphor and with solution was recorded versus temperature, while the samples were cooled in a previously heated aluminium block. The difference between the recorded deviations from a straight line was found to be a measure of the freezing point depression. Errors less than 5 % were computed for various samples.

Heat-resistant cast iron for glass press molds

Heat-resistant cast iron for glass press molds