Principle: The petal block is designed as an inclined slider, which, under the opening force of the injection molding machine, completes radial sliding and vertical movement along the inclined guide groove simultaneously during mold opening, achieving demolding.

For example, the bottom surface of the inclined slider is connected to the mold ejection mechanism. When ejected, the inclined slider moves along the inclined groove, pushing out the product upward and sliding outward to detach from the concave structure of the product.

Features:

Efficient demolding: It can simultaneously complete demolding and opening actions, suitable for circular products with complex structures such as side holes and protrusions (such as gears and flanged pipe fittings).

Applicable scenarios: Widely used in precision molds that require multi-directional demolding, especially suitable for automated production lines.

Limitations: The inclination angle of the inclined slider needs to be designed reasonably (usually not exceeding 25 °), otherwise it may cause difficulty in demolding or damage to the mold.

Hydraulic/pneumatic valve opening (power driven valve opening)

Principle: Powered by a hydraulic cylinder or air cylinder, it directly drives the opening and closing of the valve block.

For example, installing a hydraulic cylinder on the outside of the mold, connecting the piston rod to the valve block, and pushing the valve block radially or axially through hydraulic oil or compressed air.

Features:

Controllable power: It can accurately control the opening speed and force, suitable for large molds or high hardness materials (such as metal die-casting molds).

Applicable scenarios: Used for large circular products (such as car wheels, industrial pipeline fittings), or automated production scenarios that require frequent and rapid opening of the valve.

Limitations: Additional hydraulic or pneumatic systems need to be configured, which increases equipment costs and complexity.

Thermal expansion valve opening (special scenario application)

Principle: By utilizing the thermal expansion and contraction characteristics of materials, the mold disc can be opened by heating or cooling it to produce small deformations.

For example, using shape memory alloys or materials with high thermal expansion coefficients to make valve blocks, the valve blocks will automatically expand or contract and separate from the product when the temperature changes.

Features:

Non contact demolding: No mechanical drive required, suitable for precision products sensitive to mechanical stress (such as optical lenses, microelectronic components).

Applicable scenarios: Micro circular parts in the manufacturing field, or special material products that need to avoid mechanical damage.

Limitations: Dependent on temperature control accuracy, low production efficiency, narrow application scenarios.

Key factors in choosing the valve opening method

1. Product structure: Simple circular products can choose radial sliding or axial opening; Complex structures (concave sides, threads, etc.) require inclined sliders or rotating flaps.

2. Production efficiency: For large-scale production, priority should be given to hydraulic/pneumatic or inclined slider opening (high degree of automation).

3. Mold cost: Small molds can be selected with radial sliding or rotating flaps; Large molds require comprehensive consideration of the cost of the power system.

4. Material characteristics: Soft materials (such as plastics) can withstand certain mechanical stresses, while hard materials (such as metals) require gentle demolding methods (such as hydraulic drive).

In practical applications, multiple opening methods (such as inclined slider+hydraulic drive) may be combined to meet the demolding requirements of complex products.