|
| Brand Name: | SunMore |
| Model Number: | Hollow plastic products |
| MOQ: | 1 Piece |
| Delivery Time: | 45 days |
| Payment Terms: | T/T |
Rotational Molding Mold Process, Design and Engineering Specification for Hollow Plastic Products
Product Overview
Rotational molding molds are essential for manufacturing hollow plastic products through a one-piece forming process.
Plastic powder is heated and rotated along two axes, allowing material to evenly coat the mold surface.
This process is particularly suitable for large-scale products, complex geometries and customized production requirements.
Process Principle
The rotational molding process includes:
Loading material into the mold
Heating under controlled conditions
Biaxial rotation for uniform distribution
Melting and adhesion to mold surfaces
Cooling and demolding
No external pressure is applied, and material distribution is controlled by mold geometry and rotation.
Rotational Molding Engineering Control Parameters
|
Control Factor |
Range |
Engineering Purpose |
|---|---|---|
|
Heat Input Profile |
Multi-stage heating |
Ensures uniform melting |
|
Mold Surface ΔT |
≤ ±5°C |
Controls thickness consistency |
|
Biaxial Speed Ratio |
1:1 – 4:1 |
Influences material flow |
|
Powder Size Distribution |
300–500 μm |
Affects melting behavior |
|
Charge Weight |
Based on thickness |
Determines final thickness |
|
Gelation Time |
Adjustable |
Stabilizes adhesion |
|
Cooling Rate |
Controlled |
Reduces deformation |
|
Demolding Temperature |
Below softening point |
Maintains structure |
|
Thickness Variation |
±5% |
Ensures consistency |
|
Shrinkage Rate |
1.5% – 3% |
Mold compensation |
Rotomolding Mold Capability Specification
|
Capability |
Range |
Description |
|---|---|---|
|
Max Product Size |
≤ 5000 mm |
Large tanks and boats |
|
Min Product Size |
≥ 500 mm |
Small containers |
|
Max Volume |
≤ 30000 L |
Large hollow products |
|
Wall Thickness |
3 – 15 mm |
Adjustable |
|
Mold Material |
Aluminum Alloy |
Standard |
|
Structure Type |
Cylindrical / Rectangular / Complex |
Flexible design |
|
Molding Method |
Biaxial rotation |
Standard |
|
Production Mode |
Mass production |
Industrial use |
|
Surface Quality |
Controllable |
Depends on machining |
Role of Mold in the Process
The mold defines product geometry, structural integrity and wall thickness distribution.
Mold design determines material flow path and forming consistency.
Optimized mold geometry enables complex shapes, smooth transitions and functional features.
Rotomolding Design Guidelines
Proper design improves quality and reduces production risks:
Avoid sharp corners to ensure smooth material flow
Maintain uniform wall thickness across surfaces
Design adequate corner radius for stress reduction
Consider shrinkage in mold dimensioning
Ensure proper venting to prevent defects
Process Optimization Factors
Key factors influencing product performance:
Balance of biaxial rotation speeds
Uniform heat distribution across mold
Powder material quality and consistency
Cooling method and duration
Mold surface finish and precision
Process Comparison
|
Process |
Advantage |
Limitation |
|---|---|---|
|
Rotational Molding |
Seamless, large size capability |
Longer cycle time |
|
Injection Molding |
High precision |
High tooling cost |
|
Blow Molding |
Fast production |
Limited shape flexibility |
When to Choose Rotational Molding
Rotational molding is suitable when:
Large hollow products are required
Complex shapes are needed
Seamless structure is critical
Medium or low production volume is expected
Uniform wall thickness is required
Typical Issues and Engineering Solutions
Uneven wall thickness → Optimize rotation and mold geometry
Stress concentration → Improve corner design
Deformation → Control cooling rate
Inconsistent thickness → Adjust heat input and charge weight
Quality Control
Consistent production is achieved through:
Process parameter monitoring
Mold precision control
Material quality verification
Production consistency management
Selection Guidelines
Select mold design based on product geometry
Consider size and complexity
Ensure process compatibility
Optimize design based on application
Request Mold Design Evaluation
Provide your product drawings or requirements for engineering evaluation.
Supported services:
Custom mold design
Structural optimization
Process feasibility analysis
FAQ
Q1: Is high pressure required
A: No
Q2: Is it suitable for large products
A: Yes
Q3: Can complex shapes be produced
A: Yes
Q4: Does mold design affect product quality
A: Yes
