Raw Material Factors (Most Basic)
Raw material formulation and melt flowability
The higher the melt index (MI), the better the fluidity and the faster the extrusion discharge; The more calcium carbonate, glass fiber, and recycled material added, the greater the melt resistance and the lower the extrusion rate.
Raw materials with excessive moisture content easily cause bubbles, forcing production to slow down; Raw material mixing is uneven, discharge fluctuates between fast and slow, and cannot be accelerated at full capacity.
B.. Raw material temperature
If the feed temperature for powder/granular material is too high, bridging and material blockage can occur; if too low, plasticization is poor, so the traction speed should be reduced.
Extrusion Main System (Core Capacity)
A.Screw and barrel configuration
- Screw length-to-diameter ratio and compression ratio: Matched with corresponding raw materials (PE/PP/PVC); If the selection is too small, plasticization is insufficient, so only low speed is possible; If the selection is too large, it is prone to overheating and decomposition.
- Screw wear, increased edge gaps, plummeting conveying efficiency, unstable discharge, and a significant drop in output.
- Temperature control system
- Barrel and die head temperatures in each zone are too high, melt is too thin, causing expansion and uneven tube wall thickness; If the temperature is too low, plasticization is incomplete, so the extrusion speed must be reduced, directly reducing output.
- Drive and transmission
- Insufficient motor power, aging inverter, reducer failure, and maximum screw speed are limited, preventing the designed extrusion volume from being reached.
Machine Head Mold Shaping System
A.. Mold runner design: high runner resistance, small mold opening, high discharge resistance, and low capacity ceiling; Mold opening scorching and material accumulation blockage, forcing reduced speed for cleaning.
- Sizing sleeves and vacuum chambers: Unstable vacuum negative pressure, clogging of cooling water in sizing sleeves, substandard pipe roundness, and inability to speed up traction; Insufficient cooling during the setting process, pipe deformation, and production at limited speed
- Traction and cutting auxiliary machines (speed limit is key)
A, Traction machine: Slippery tracks/rubber blocks, traction motor frequency failure, insufficient clamping force, unable to increase traction speed; Traction is the bottleneck of the entire line; the traction limit ≈ the actual production capacity limit of the entire line.
- Cooling System: Insufficient cooling water flow and high temperature in the spray water tank and vacuum box, insufficient cooling after pipe shaping and formation, high-temperature pipes easily deform, and only a reduced traction speed can be achieved.
- Cutting machine and winding: The cutting machine responds slowly, saw blades get stuck, and frequent stops during rewinding and rerolling, with frequent start-stops lowering hourly output.
- Process parameter matching
- Ratio of extrusion speed to traction speed: Imbalance in ratio will cause the pipe wall to be too thick or too thin, and can only be corrected by reducing speed;
- Screw feeding speed: feeding too fast causes material blockage; feeding too slowly causes screw shortage, resulting in interrupted discharge.
- Equipment Operation and Maintenance and On-site Management
- Vulnerable parts: filter screen blockage (frequent screen stoppages), bearing wear, heating ring damage, single-point temperature control failure, intermittent speed reduction;
- Frequency of specification changes: frequent changes in pipe diameter and wall thickness, stopping machines for mold adjustment and process changes, resulting in a decrease in daily output;
- Manual operation: screen replacement, fault troubleshooting, and corner scrap rework and shutdown time required.
- Pipe specifications themselves
On the same extrusion line: the larger the pipe diameter and the thicker the wall, the lower the yield per unit meter; Line speed of thin-walled small tubes
Fast and highest output. Example: one 20mm small pipeline can reach speeds above 30m/min, while large-diameter solid-walled pipes are only 0.2～8m/min.
Jiangsu Xinrongplas Machinery Co., Ltd. is specialized in the production of pvc, hdpe ppr pvco pipe extrusion lines. We are looking forward to cooperating with you.