High-Pressure Proportional Pressure Regulator for Physical Foaming Technology

The core of physical foaming technology revolves around the role of high-pressure proportional valves in determining cell quality and product stability

In the contemporary high-performance plastic manufacturing industry, physical foaming technology is progressively replacing conventional chemical foaming methods.
It is widely used in lightweight structural components, thermal insulation materials, cushioning products, and high-end engineering plastics.

However, many manufacturers discover after adopting physical foaming that the true determinant of product quality lies not in the material itself, but in the ability to control gas pressure.
In such cases, high-pressure proportional pressure control technology is paramount.KaoLu's High Pressure Proportional Pressure Regulator has already been stably utilized in physical forming machine.

What is physical foaming?
It is essential to understand the necessity of high-pressure gas control.

Physical foaming involves injecting high-pressure gas (such as CO₂ or N₂) into molten polymer to create a supercritical state.
Upon pressure release, this process forms a uniform, fine-bubble structure.

Typical operating conditions include:

• The optimal range for CO2 pressure is 150 to 300 bar
• The nitrogen pressure range is from 100 to 250 bar
• The material will be subjected to a high-temperature, high-pressure melt environment
• Gas flow necessitates real-time adjustment during processing

This system is highly dynamic and operates under high pressure, where even slight fluctuations in pressure can directly impact foaming quality.

The True Cause of Unstable Foaming Quality

Many foaming issues are not derived from raw materials, but rather from imprecise gas control.

• There is an issue with the uneven cell size
• There is a need to consider density variations
• The product has exhibited signs of surface pitting and silver streaks
• The foaming expansion ratio drift is a key concern

You can see that physical foaming is fundamentally a "high-pressure dynamic fluid control problem."

What are the limitations of traditional pressure-reducing valves in meeting physical foaming demands?

Traditional pressure-reducing valves are characterized by the following properties:

• Static pressure regulation
• Slow response
• Susceptible to flow variations
• Incompatible with digital control

Traditional mechanical pressure-reducing valves are designed for steady-state pressure environments. In contrast, physical foaming involves high-speed dynamic conditions.

High-pressure proportional valves, dynamic closed-loop control, millisecond response, stable, repeatable pressure, and integration with PLC/control systems are key features of electronic proportional pressure control technology.
This technology is becoming a standard feature in increasingly advanced foaming equipment.

There are three core roles of high-pressure proportional valves in physical foaming:

1. Precise control of supercritical gas pressure is paramount for achieving uniform microcellular structures.

Ensuring stable gas pressure within the supercritical range is crucial for the successful formation of these structures.

2. Dynamic flow synchronization adjustment

The proportional valve is required to make instant adjustments to output in response to changes in screw speed and melt flow rate.

3. Stabilization of bubble size and density

Pressure stability directly determines consistent cell size and product weight.

The advantages of high-performance proportional control technology

For physical foaming applications, an ideal pressure control device must possess the following characteristics:

- Capable of high-pressure control (suitable for CO2/N2 high-pressure environments)

This product is distinguished by its high-precision pressure resolution.

The system demonstrates a high-speed, dynamic response.

The system has been engineered for long-term, stable operational capability.

- Ensure seamless integration and compatibility with digital control systems.

These characteristics represent the design direction for next-generation pressure proportional valves.

As the demand for lightweight, high-performance materials continues to rise, physical foaming will become a pivotal technology in plastics manufacturing.
The key to ensuring product quality and stability does not lie in the material itself, but rather in the precision of gas pressure and flow control.

Proportional pressure control technology is becoming the standard configuration for high-end foaming equipment, as it is increasingly replacing traditional solutions in the realm of high-pressure dynamic fluid control.