Cooling and shaping is a critical process in sheet extrusion production. After the molten material leaves the die, it remains at a high temperature. If cooling is not properly controlled, defects such as sheet warping, uneven thickness, surface wrinkles, and high internal stress may occur.Many operators focus on extruder parameters but overlook cooling details, resulting in unstable product quality. Based on practical commissioning experience, Benk Machinery summarizes key cooling and shaping methods for sheet extrusion production lines.

Proper Control of Roller Temperature

1.Roller Temperature Zoning

Cooling rollers for sheet extrusion production machine should not be set to the same temperature. The temperature should be adjusted according to the sheet material and thickness.The first roller contacting the hot melt should not be too cold, as rapid cooling may increase internal stress. Later rollers should gradually reduce temperature to achieve step-by-step cooling.Different materials such as PP, PE, and PVC sheets require different roller temperature settings, which should be adjusted based on material characteristics.

2.Check Roller Temperature Uniformity

Poor cooling water circulation inside rollers may cause uneven surface temperatures, leading to strip-like waves on the sheet surface.Regular inspection of the cooling water system is necessary to prevent scale buildup and pipe blockage.

Matching Cooling Roller Speed with Haul-Off Speed

1.Synchronized Speed Control

The cooling rollers and haul-off unit must maintain synchronized speeds. Excessive speed differences may cause sheet stretching, looseness, or wrinkles.Benk Machinery extrusion lines are equipped with synchronized speed control systems to reduce defects caused by speed mismatch.For thick sheets, cooling time should be increased, and production speed should not be raised blindly.

2.Adjust Roller Gap Pressure

Roller pressure should be properly controlled.Too little pressure may cause poor contact between the sheet and rollers, reducing cooling efficiency.
Excessive pressure may damage the hot melt surface and create pressure marks.

Environmental and Auxiliary Cooling Considerations

1.Workshop Environment Control

Large temperature fluctuations in the workshop can affect the natural cooling process of sheets.Avoid direct airflow onto hot sheets after leaving the rollers, as sudden local cooling may cause deformation.

2.Proper Use of Air Cooling

For some thick sheet products, additional air cooling may be required.Airflow speed and direction should be uniform to prevent local strong airflow from affecting sheet flatness.

4. Cooling After-Treatment and Stress Release

Even after leaving the cooling unit, sheets may still contain residual heat.Do not wind sheets immediately after cooling. Allow sufficient natural cooling time to release internal stress and reduce deformation during storage.

FAQ

Q1: What causes sheet warping after cooling?

A: It is mainly caused by improper cooling gradients, uneven roller temperature, or early winding before internal stress is released.

Q2: For thin sheet production, is a lower cooling roller temperature always better?

A: No. Excessively low temperatures can cause rapid cooling and increase internal stress, leading to later deformation.

Q3: Does cooling water scaling affect sheet quality?

A: Yes. Scale buildup can block water channels, causing uneven roller temperatures and surface defects.

Q4: Does Benk Machinery sheet extrusion line support temperature zoning control?

A: Yes. The cooling system supports customized gradient cooling settings for different sheet materials.

Q5: How can thick sheets improve cooling performance?

A: Reduce production speed appropriately, add uniform air cooling, and extend the overall cooling path.

Why Choose Benk Machinery?

From individual machines to complete production lines, Benk Machinery provides reliable and customized plastic processing
solutions. Since 2012, we have focused on plastic extrusion, nergy-saving plastic recycling machine, and automated compounding centralized feeding systems, helping customers build efficient and cost-effective production facilities.

• Complete Extrusion Solutions: Professional expertise in plastic pipe, profile, sheet, plate and board extrusion lines.
• Customized Project Solutions: Equipment and production lines can be configured according to your materials, products, capacity and factory requirements.
• Stable & Cost-Effective Equipment: Reliable machine performance, efficient production and optimized energy consumption help reduce operating costs.
• Professional Service: From technical consultation and production to installation, commissioning and after-sales support, our team provides complete project assistance.

Contact Benk Machinery:

PPlanning to upgrade your factory? Contact Benk Machinery for a customized project solution.

• Email: [email protected]
• Tel / WhatsApp: +8615950962426