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What are the key technical considerations in the extrusion process for sealing strip extruders?

Time：

2022-06-06

I believe that, for many people, the sealing strip extruder is a well‑known piece of equipment. Numerous chemical enterprises rely on it, and thanks to its excellent performance and high production efficiency, it has won widespread favor. Now, let’s take a look at the key technical aspects of sealing strip extrusion.

I believe that, for many people, the sealing‑strip extruder is a well‑known piece of equipment. Numerous chemical enterprises rely on it, and thanks to its excellent performance and high production efficiency, it has won widespread favor. Now, let’s take a look at the key technical aspects of sealing‑strip extrusion.

1. Seal strip extruder Technical Highlights

1. During the extrusion process, the material transitions from a glassy state to a molten state. In addition to maintaining a stable thermal balance between the heat required for plasticization and the feed‑in heat to ensure optimal plasticization, melt pressure is another critical control parameter. Because the material is subjected to die resistance and the compression ratios at each stage of the screw during extrusion, it does not remain at atmospheric pressure; moreover, the compression ratios at different stages are essentially balanced and stable, rather than variable.

2. Under the condition of a constant extrusion speed, when the feed rate is increased or decreased, the material capacity of the feeding screw changes, while the material capacity in the venting section remains unchanged. Consequently, the feeding and compression sections vary with the compression ratio, and the melt depth pressure rises or falls accordingly. Similarly, when the extrusion speed is adjusted—while the feed rate is held constant—the material capacity of the feeding screw also changes.

Since the material capacity in the discharge section remains constant, the feed and compression sections experience changes in melt depth as the compression ratio varies; the feed rate increases or decreases in tandem with the extrusion rate. However, the screw’s material capacity in the feed section stays unchanged, with variations in melt pressure arising solely from changes in speed.

II. Seal strip extruder Problem Analysis

1. The scaffold frame is severely worn.

If the clearance between the cutter head frame and the inner wall of the mud tank is excessive, or if the helix angle of the cutter blades is incorrect, care should be taken during replacement to ensure a clearance of 3–5 mm and to fabricate the cutter blades according to the design angles.

2. The surface is too rough.

The surface of the aperture blades is excessively rough, resulting in excessive friction between the mud and the blades. When rebuilding the aperture by surfacing welding, avoid patchwork welding; replace the entire assembly at once, proceeding gradually to ensure the brickwork is completed smoothly.

3. Severe wear on the cylinder liner of the mud tank

When the clearance between the cutter suction blade and the hopper wall is excessive, the sludge rotates excessively within the hopper, preventing it from exiting or entering. In such cases, the hopper liner should be replaced, or several reinforcing ribs—parallel to the liner’s inner wall or inclined axially—should be installed to suppress the sludge’s ineffective rotation, thereby compensating for the worn grooves and enhancing effective squeezing.

4. The gap is too large.

The gap between the sludge‑pressing plate and the racking frame is too large to allow effective sludge scraping. In this case, the clearance between the knife plate and the aperture blades must be adjusted or repaired by welding and replacement, ensuring it is less than 10 millimeters.

The above is what has been introduced. Seal strip extruder What are the key technical points of the process? For more information, please feel free to contact us at any time!