What happens when the melt temperature is wrong?
Melt temperature can be too high or too low: both are wrong. In addition, even distribution of temperature in the melt is also a factor to be kept in mind. Temperatures that are too high degrade the polymer, that is, destroy the molecular chains. Another consequence may be that additives in the melt, such as pigments, impact modifiers, etc., also decompose. The results are poorer mechanical properties (as a result of the shorter molecular chains), surface defects (caused by decomposition products) and unpleasant odours. When the temperature is too low, the structure fails to achieve the required homogeneity. This drastically reduces impact resistance and leads in most cases to considerable variations in physical properties. Apart from the melt temperature, the polymer’s dwell time in the injection unit also plays an important role. Experience has shown that dwell times of between two and nine minutes are normal. If the dwell time is longer, thermal decomposition may take place in certa
