Many of the malfunctions and wear issues encountered during the selection and actual operation of melt pump heating systems are directly related to improper heating methods and unreasonable configurations. These issues primarily fall into the following four categories:

First, poor temperature uniformity. An unreasonable layout of electric heating elements or obstructed heat transfer fluid circulation lines can cause temperature differences of over 5°C across the pump body, leading to localized overheating. This directly results in melt degradation and carbonization, causing defects such as color variations, flow marks, and crystalline spots in the final products. In precision extrusion applications such as medical catheters and films, this can easily lead to the scrapping of entire batches.

Second, high energy consumption and maintenance costs. Some large production lines blindly adopt electric heating, with multiple heating elements operating simultaneously, resulting in persistently high power consumption. Meanwhile, in thermal fluid heating systems, pipeline leaks or failure to promptly replace aged fluid can significantly reduce heating efficiency—in some operating conditions, by more than 30%—thereby increasing energy consumption and prolonging downtime for maintenance.

Third, there is a lack of adaptability to specific operating conditions. When electric heating is used for high-viscosity materials, it is prone to localized overheating and excessive shear; conversely, selecting thermal fluid heating for small pilot lines or low-capacity production lines results in excessively high initial investment and low system utilization, leading to a waste of resources and costs.

Fourth, equipment service life is shortened. When temperature fluctuations exceed ±3°C, the pump’s gears, bushings, and seals are subjected to frequent thermal expansion and contraction, leading to thermal fatigue, accelerated wear, and coking on sealing surfaces, which significantly shortens the overall service life of the equipment. For instance, an LLDPE production line once experienced gear damage due to excessive temperature fluctuations, resulting in a 36-hour shutdown of the entire line and significant losses.