Unterschiede
Hier werden die Unterschiede zwischen zwei Versionen angezeigt.
| Beide Seiten der vorigen RevisionVorhergehende ÜberarbeitungNächste Überarbeitung | Vorhergehende Überarbeitung | ||
| en:berechnungen:aufschmelzverlauf [2025/06/27 13:26] – [Calculation of melt pool formation location] cschall | en:berechnungen:aufschmelzverlauf [2025/07/03 13:34] (aktuell) – cschall | ||
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| - | The solid bed is deposited on the non-driving (passive) flank of the screw channel. As the plastic melts, it is carried away to the active flank of the screw channel by the relative movement between the screw and barrel and by the ‘scraping’ by the screw flights. This creates a melt vortex, which simultaneously presses the solid bed against the non-driving flank. \\ | + | The solid bed is deposited on the non-driving (passive) flank of the screw channel. As the plastic melts, it is carried away to the active flank of the screw channel by the relative movement between the screw and barrel and by the ‘scraping’ by the screw flights. This creates a melt pool, which simultaneously presses the solid bed against the non-driving flank. \\ |
| - | As the melting process continues, the solids bed becomes narrower, but retains its height due to the pressure of the melt vortex. The solid bed width therefore decreases as a result of the melting process. If the channel geometry remains constant, the solids bed width decreases continuously. If the channel volume is reduced (lower channel depth, bigger flights, multi-flight section, lower channel pitch, restriction to the solid channel in barrier screws), the solids bed width increases, as the solids volume flow remains constant. | + | As the melting process continues, the solids bed becomes narrower, but retains its height due to the pressure of the melt pool. The solid bed width therefore decreases as a result of the melting process. If the channel geometry remains constant, the solids bed width decreases continuously. If the channel volume is reduced (lower channel depth, bigger flights, multi-flight section, lower channel pitch, restriction to the solid channel in barrier screws), the solids bed width increases, as the solids volume flow remains constant. |
| The dimensionless solids bed width $y$ shown in REX is normalised to the channel width: $y = \frac{solids bed width}{channel width}$ | The dimensionless solids bed width $y$ shown in REX is normalised to the channel width: $y = \frac{solids bed width}{channel width}$ | ||
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| ==== Calculation of the melt fraction ==== | ==== Calculation of the melt fraction ==== | ||
| - | The melt fraction is calculated from the current normalised solids bed width $y$, the current channel width $b$, channel height $h$, number of channels $i$, and the current solids bed velocity $v_{fz}$ in relation to the channel geometry at the location of the melt vortex | + | The melt fraction is calculated from the current normalised solids bed width $y$, the current channel width $b$, channel height $h$, number of channels $i$, and the current solids bed velocity $v_{fz}$ in relation to the channel geometry at the location of the melt pool formation and the solids bed velocity $v_{fz, |
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