Unscrewing Mold - Kehui Mold Co., Limited

The unscrewing mold is a special die used to process parts with thread structures. It realizes the forming of the thread part through specific design and process. The unscrewing mold is widely used in the manufacturing industry, especially in the fields of automobile, medical, electronics, and other fields that require high thread precision.

Definition and Characteristics of Unscrewing Mold

1. Definition of Unscrewing Mold

The unscrewing mold is a special type of injection mold, which is used to mold products with internal or external threads. It can smoothly de-mold the product after molding and maintain the integrity of the thread through the cooperation of the thread structure in the mold and the demolding mechanism.

2. Characteristics of Unscrewing Mold

High Precision: High requirements for the size and shape accuracy of the thread.
Complex Structure: A special rotary demolding mechanism needs to be designed, such as an undercut or unscrewing mechanism.
Strong Applicability: suitable for products of various materials, such as plastic, metal, etc.
Efficient Production: Thread processing is completed in one injection molding, without subsequent processing.

Application Scenarios of Unscrewing Molds

Bottle Caps and Containers: Such as mineral water bottle caps and cosmetic bottle caps.
Medical Devices: Such as the threaded interface of syringes.
Electronic Products: Such as the threaded part of the connector housing.
Mechanical Parts: Such as pipe joints, threaded shafts, etc.

Design Method of Unscrewing Mold

1. Product Structure Analysis

Determine Thread Parameters: Analyze the product’s thread type (such as metric thread or imperial thread), pitch, diameter, and depth.
Analyze De-molding Direction: Determine the appropriate demolding mechanism according to the direction and angle of the thread.

2. Select the Appropriate Demolding Mechanism

Mechanical Core Pulling Mechanism: Driven by gears or racks to achieve rotary de-molding of internal thread products.
Hydraulic or Pneumatic Drive: Use hydraulic cylinders or cylinders to drive the core components to rotate, suitable for larger thread products.
Manual Demoulding: Suitable for simple products produced in small batches.

3. Mold Structure Design

Parting Surface Design: Determine a reasonable parting surface according to the product structure to avoid interference with the thread.
Core Component Design:
Thread Core: Design a core part that fully matches the product thread.
Core Pulling Mechanism: Ensure that the thread core can be smoothly rotated and demolded when the mold is opened.
Mold Steel Selection: Select materials with high wear resistance and strength (such as P20 or H13 steel).

4. Cooling and Pouring System Design

Cooling System: Arrange cooling water channels in the thread area to ensure uniform mold temperature and avoid deformation.

Gating System

Select an appropriate gate position to ensure that the molten material can fill the thread area.
Optimize the runner design to reduce pressure loss.

5. Mold Flow Analysis and Optimization

Use mold flow analysis software (such as Moldflow) to simulate the thread-forming process, verify the rationality of the design, and optimize:
Check whether the material filling is uniform to avoid bubbles or material shortages in the thread.
Optimize the stress distribution during demoulding to prevent thread deformation.

Common Problems and Solutions in the Design of Unscrewing Mold

1. Incomplete Thread Forming

Problem Cause: Insufficient material filling or insufficient pouring pressure.
Solution: Adjust the gate position and increase the injection speed and pressure.

2. Difficult Unscrewing Demolding

Problem Cause: Improper design of the core pulling mechanism or excessive thread angle.
Solution: Optimize the core pulling mechanism, add lubricant, or change the thread design.

3. Severe Mold Wear

Problem Cause: Frequent movement of the thread area causes wear.
Solution: Select high-hardness mold steel and maintain it regularly.

4. Product Surface Defects

Problem Cause: Uneven cooling or poor mold surface treatment.
Solution: Optimize the cooling system and improve the surface finish of the mold.

The unscrewing mold play an important role in modern manufacturing. Their design needs to be considered comprehensively in combination with product characteristics, production requirements and technical conditions. From structural analysis to mold flow optimization, each step determines the quality and production efficiency of the final product.

By rationally designing and maintaining unscrewing mold, not only can production efficiency be improved, but also high precision and consistency of threaded products can be ensured, bringing greater competitive advantages.