Screw length 970 INDEX

From this equation, the various parameters that influence the temperature rise by viscous dissipation can be cleariy distinguished. The temperature rise increases with consistency index (m), the length (L), the screw diameter (D), the screw speed (N), and the power law index (n). The temperature rise reduces with melt density (p), the specific heat (Cp), the channel depth (H), the throttle ratio (rt), and the helix angle (cp). 

In order to understand this, let us consider the case of a unit cell with a 2, screw axis parallel to a. Since the screw axis involves translation by a/Z the structure is reproduced not after a translation by a, but by a/2 (albeit with a 180° twist). Thus, it appears that the unit cell length is a/2 and not a. This leads to the disappearance of every reflection due to planes with indexes (AOO), where h is odd. Similarly, a twofold screw axis parallel to b leads to the extinction of (OkO) reflections with k odd, and for one parallel to c, to the absence of (001) with I odd. 

The experimental flow curves obtained at constant injection pressure under given melt temperature, mold temperature and axial screw speed are given schematically in Figure 2 for a resin type at various spiral heists with melt flow index of the polymer brand as parameter. By comparing the flow lengths with one another at any spiral height also called wall thickness, the flowabihty of the resin brand in qnestion with reference to another brand can be inferred (1), (2). 

---