Glass Pressing
The glass pressing process is extensively used to produce a large number of products. Among others are TV panels, tableware (dishes, asher, drinking glass, etc.) or preform for future blow molding application (press and blow process). Although most people may think that little technology is needed to produce something as common as a drinking glass or a dish, keeping the product quality high and the production costs down are challenges that require advanced technologies to accomplish. The market constantly demands thinner container walls, lighter objects and better textures making glass production far more complex than the apparent commonality of the goods it produces. Too fast of a plunger motion can lead to excessive residual stress or even product breakage during production, thermal effects may induce some weaknesses in the product and possible risk of later breakage. However, proper operating conditions may ensure an item's weight reduction. This competitive advantage can make a substantial difference between two glass companies.
Fluent software has been used successfully to improve the glass pressing process for many years. The combination of free surface deformation under the combined effect of the motion of different solid devices (molds, plunger(s), etc.), gravity, the cooling process (mainly due to the heat exchange with the mold and the plunger), the mechanical and thermal detection of the contact between the deforming glass and the moving and still molds despite the thin slit remaining between all this parts, create a better understanding of the subtleties of the glass pressing process. This better understanding quickly leads to tremendous savings in manufacturing cost and time while ensuring a high quality final product.
Glass pressing is probably the application where the deformations are the largest. In Figure 1, the process begins with a spherical sample of glass that becomes a typical dish. Here, the initial grid can not support such an extreme deformation. Therefore, specific advanced techniques such as the adaptive meshing method have been implemented in Fluent's software to ensure both a high robustness of the simulation and an easy to learn problem set-up. During the deformation process, the solver automatically refines the mesh where this is necessary. Refinement may appear where very large deformations occur or where the geometrical details of the mold require them. Intelligent algorithms automatically refine the grid only where and when this is necessary during the run both in 2D and in 3D. These techniques are especially important when small geometrical details are involved in the final product. Fluent's software lets you refine the mesh to close these details while keeping larger elements elsewhere in order to reduce to global computational time.
