Effect of Screw Speed on Blow Molding Machine

The screw speed directly affects the output of the blow molding machine and the quality of the product parison, with its optimal value contingent upon the dimensions and configuration of the screw, the nature of the extruded products, and the properties of the raw materials used. An increase in screw speed can markedly enhance the output of the blow molding machine, albeit with a proportional rise in energy consumption. For manufacturers aiming to boost production volumes, a higher screw velocity presents a tangible benefit.

Additionally, an escalated screw speed augments the plasticizing efficacy of the material, thereby refining the microscale quality of the product owing to the intensified shearing action imparted by the screw. Nevertheless, this escalation in speed must be judiciously moderated. Exceeding an optimal threshold can result in insufficient dwell time of the plastic within the barrel, potentially leading to irregular melt temperatures and diminished surface integrity of the parison. This is particularly crucial when processing high-density polyethylene materials with an hdpe blow moulding machine, as an excessive shear rate might precipitate melt fracture phenomena.

Furthermore, the elevation in screw velocity engenders a significant generation of frictional heat, risking the immediate thermal degradation of the plastic. Hence, meticulous calibration of the screw speed is imperative, tailored to the specific operational milieu and material characteristics.

Elevating the screw speed is a nuanced strategy to amplify the blow molding machine's output while enhancing the qualitative attributes of the product. However, this enhancement must be balanced against the risk of thermal degradation and material instability, especially when engaging sophisticated machinery like the jwell blow molding machine or when specific applications demand specialized equipment like a plastic pallet machine.

In the past, the main way to increase the output of blow molding machines was to increase the diameter of the screw. Although the screw diameter increases, the material extruded per unit time will increase. But a blow molding machine is not a screw conveyor. In addition to extruding the material, the screw also needs to squeeze, stir and shear the plastic to make the plastic plastic. On the premise that the screw speed remains unchanged, the screw speed of the ordinary blow molding machine, the traditional blow molding machine is 60 to 90 rpm (per minute, the same below). Now it has generally been increased to 100~120 rpm. A blow molding machine with a higher speed reaches 150 to 180 rpm. It is reported that the screw speed of the blow molding machine produced by a certain blow molding machine manufacturer is above 200 rpm.

If the screw diameter remains unchanged and the screw speed is increased, the torque on the screw will increase. When the torque reaches a certain level, the screw may be twisted. However, by improving the material and production process of the screw, rationally designing the screw structure, shortening the length of the feed section, increasing the flow rate of the material, and reducing the extrusion resistance, the torque can be reduced and the bearing capacity of the screw can be improved. How to design the most reasonable screw to maximize the screw speed under the premise that the screw can withstand it requires professionals to obtain through a lot of experiments.

For blow molding machines with the same screw diameter, high-speed and high-efficiency blow molding machines consume more energy than conventional blow molding machines, and it is necessary to increase the power of the motor.

Blow molding machines with the same screw diameter are equipped with larger motors, which seem to consume electricity, but if calculated according to output, high-speed and high-efficiency blow molding machines are more energy-efficient than conventional blow molding machines. And this is just a comparison of the energy consumption of the motor. If the power consumption of the heater and fan on the blow molding machine is taken into account, the difference in energy consumption will be even greater. A blow molding machine with a large screw diameter needs to be equipped with a larger heater, and the heat dissipation area is also increased. Therefore, for two blow molding machines with the same production capacity, the barrel of the new high-speed and high-efficiency blow molding machine is smaller, and the energy consumption of the heater is less than that of the traditional large screw blow molding machine, which also saves a lot of electric energy in heating.

In terms of heater power, compared with ordinary blow molding machines with the same screw diameter, the high-speed and high-efficiency blow molding machine does not increase the power of the heater due to the increase in production capacity. Because the power consumption of the heater of the blow molding machine is mainly in the preheating stage. During normal production, the heat of material melting is mainly converted by consuming the electric energy of the motor. The conduction rate of the heater is very low, and the power consumption is not high. Large, which is more obvious in high-speed blow molding machines.