Melt transport and shaping

Injection molding is a cyclic process for producing discrete identical articles from a hollow mold which is appropriately shaped to give the final product profile. Injection molding equipment consists of two parts (1) the injection unit and (2) the clamping unit. The function of the injection unit is to melt, transport, and inject the polymer into the mold, whereas the clamping unit is involved... 

Mixing and homogenization Melt transport Primary shaping Secondary shaping Shape stabilization Finishing operations. 

In this description the temperature field has been taken to be linear in the coordinate y and to be independent of the shape of the melt/crystal interface. This is a good assumption for systems with equal thermal conductivities in melt and crystal and negligible convective heat transport and latent heat release. Extensions of the model that include determination of the temperature field are discussed in the original analysis of Mullins and Sekerka (17) and in other papers (18,19). 

Examples of dimensionless groups that specify ratios of transport mechanisms are listed next in Table II and depend on the size and shape of the domain. The Peclet numbers for heat (Pet) and solute (Pes) and momentum (Re) transport are ratios of scales for convective to diffusive transport and depend on the magnitudes of the velocity field and the length scale for the diffusion gradient. Boundary layers form at large Peclet numbers (Pet or Pes) or Reynolds numbers (Re). The fonnation of a boundary layer at a large Re is particularly important in crystal growth from the melt, because the low... 

For packaging, transportation, storage of Uquids, chemicals, pharmaceuticals, etc., a high variety of hoUowware is produced in the shape of bottles and tubes. Most of the products are made from soda-Ume glass (Table 3.4-3) directly from the glass melt Vials and ampoules are manufactured from tubes for pharmaceuticals these are made from chemically resistant borosilicate glass. 

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