Minor errors in raw materials, temperature, equipment and operation will cause defects in the hose's appearance, size and performance. This article lists common extrusion problems, simple causes and practical solutions for production guidance.
1. Uneven Wall Thickness & Dimensional Deviation
Problem: Ununiform wall thickness, unstable pipe diameter and poor roundness.
Causes: Unstable extruder and traction speed; die eccentricity; uneven PVC plasticization; equipment vibration.
Solutions: Calibrate the die regularly; stabilize extrusion and traction speed; adjust temperature for even plasticization; fix vibrating equipment parts.
2. Hose Surface Bubbles & Blisters
Problem: Bubbles on hose surface, reducing tightness and pressure resistance.
Causes: Wet raw materials; overhigh extrusion temperature causing material decomposition; blocked extruder exhaust.
Solutions: Dry raw materials before production; lower excessive processing temperature; clean exhaust vents regularly.
3. Interlayer Delamination (Inner Tube / Fiber / Outer Layer Separation)
Problem: Interlayer delamination between inner tube, fiber layer and outer layer, leading to water leakage and pressure failure.
Causes: Insufficient preheating; residual moisture on fiber layer; poor material adhesion; too fast cooling speed.
Solutions: Improve preheating effect to dry fiber layers; adjust PVC formula for better adhesion; slow down cooling speed for tight lamination.
4. Rough & Matte Hose Surface
Problem: Rough, streaky or matte hose surface, failing appearance standards.
Causes: Incomplete PVC plasticization; dirty or worn die; unreasonable lubricant ratio; unstable extrusion pressure.
Solutions: Adjust temperature for full plasticization; clean and polish the die; optimize lubricant proportion; stabilize feeding and extrusion pressure.
5. Hose Bending & Deformation After Shaping
Problem: Curved, twisted or flat hoses with poor straightness and roundness after shaping.
Causes: Uneven cooling water distribution; unstable traction tension; irregular fiber braiding; residual internal stress.
Solutions: Balance cooling water spray; stabilize traction tension and speed; standardize braiding density; extend cooling time to release internal stress.
6. Low Pressure Resistance & Easy Bursting
Problem: Low pressure resistance; hose bulges or bursts under standard working pressure.
Causes: Low braiding density or broken yarns; thin tube wall; poor material toughness; unfilled fiber gaps.
Solutions: Adjust braiding parameters for standard density; control wall thickness strictly; improve PVC material toughness; increase extrusion pressure to fill fiber gaps fully.
7. Extrusion Material Blocking & Uneven Feeding
Problem: Material blocking and uneven feeding, causing discontinuous hose molding.
Causes: Agglomerated raw materials; blocked extruder screw and barrel; improper temperature causing material curing.
Solutions: Screen loose raw materials before feeding; clean extruder regularly; optimize segmented extrusion temperature.
Most PVC hose extrusion defects come from unstable raw materials, improper temperature control, faulty equipment and non-standard operations. Strict material inspection, accurate temperature setting, regular equipment calibration and standardized production can effectively avoid common problems, ensuring stable hose quality and performance.
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