Open petal mold, also known as easy to retract combination mold, is generally composed of 3-4 petals (3 circular/4 square) inner cores combined into a mold cavity, which is fixed in shape by a circular sleeve covering the inner core from top to bottom; Its operation is simple, the mold is quickly removed, and the success rate is high, which is deeply loved by users. It is mainly targeted at some ultrafine powders or powder samples that are difficult to form and have difficulty removing the film. Customized according to user needs, commonly available are cylindrical and square split molds, and other shapes can also be customized.
1、 Open valve mold: structure and principle
Composed of separable modules, it solves the problem of complex product demolding by opening and closing the mold flaps through inclined guide columns or hydraulic drive. For example, the threaded bottle cap can be separated and removed along the thread direction to ensure product integrity.
2、 Manufacturing process: precise carving from design to finished product
（1） Design blueprint
Based on the 3D model of the product, determine the number and opening direction of the mold flaps, consider the material shrinkage rate and demolding slope, and use UG and SolidWorks to simulate the motion trajectory to prevent interference.
（2） Material selection
The mold core and mold disc are made of P20 and H13 tool steel (HRC48-52 after heat treatment), and the guide components are made of wear-resistant alloy steel. The precision mold can be chrome plated to reduce friction.
（3） Processing technology
3、 Breaking through Difficulties: The Path to Overcoming Core Technologies
（1） Sealing of parting surface
If the gap exceeds 0.02mm, it is prone to flying edges, and can be processed into a circular sealing groove or matched with a conical surface.
（2） Synchronous opening and closing control
Multiple petals need to move synchronously, such as the gear rack linkage used in car lampshade molds.
（3） Cooling system optimization
The segmentation of the template restricts the waterway, and 3D printing of conformal cooling channels improves efficiency by more than 40%.
4、 Maintenance and upgrade: make the mold shine with lasting vitality
（1） Daily maintenance
Regularly check the wear of guiding components and retest the fit clearance every 50000 times of opening and closing.
（2） Upgrade Strategy
Surface nitriding extends the lifespan to over 2 million mold cycles; Attempt induction heating inside the mold to reduce the risk of deformation in thin-walled products.