How does a melt pump work?

Melt pumps consist of two gears, usually driven by a single motor. The extruder fills the gears from the suction side (see diagram), and the rotating gears discharge the polymer on the other side. By precisely controlling the output of melt it eliminates many of the variables that impact extruder throughput stability.

What is melt pump?

The melt pump (or gear pump) is known as an accurate metering device that eliminates surging of the extruder screw, reduces back pressure and increases output of the complete line (up to 20%). It is used in a wide range of applications from PET sheet and rubber extrusion to recycling and compounding.

How do changes in die pressure affect the extruder output?

Due to an increase in the pressure flow portion of extruder output, the pressure and output increase of the melt to the die is somewhat less than the increase in extruder screw speed, but this effect is typically small. The output instability or surging of the extruder corresponds with the melt pressure at the die.

Why melt pump is used in sheet film extrusion process?

Melt pumps are used to build up constant pressure and ensure constant output. The extruder screw is relieved, this enables a higher output power and increases the flexibility in different applications. When a melt-pump is installed in extrusion-line the screw is not anymore responsible for the full pressure build-up.

What is a screen changer?

A continuous screen changer is a machine that filters out impurities in the polymer extrusion process—without interrupting the process when a dirty screen needs to be changed. It’s used in melt filtration processes where debris can clog up screens in a very short time and process disruptions are costly.

What is melt pressure?

Melt pressure measured with pressure sensors at the die is a sensitive measure of the overall process stability.

What is extrusion pressure?

In direct extrusion process, metal begins to flow through the die at the maximum value of the pressure called “break through pressure”. Therefore extrusion pressure is almost constant with increase in ram travel. • It represents the stress required to deform the metal through the die.

How do you fix an inconsistent extrusion?

Below are the main solutions that are effective in solving problems of inconsistent extrusion.

Increase Your Printing Temperature.
Make Sure the Nozzle is Not Clogged.
Make Sure That the Nozzle is at a Good Height.
Check the PTFE Tube.
Use a Filament of High Quality.

How does a melt pump work?