Rotomolding Service

Rotomolding primarily uses thermoplastic resins in powdered form, chosen for their durability, flexibility, and chemical resistance. The most commonly used materials at KingStar Mold include:

• Linear Low-Density Polyethylene (LLDPE): The most popular rotomolding material, known for its excellent impact resistance, UV stability, and flexibility. Ideal for outdoor products, tanks, and coolers.

• High-Density Polyethylene (HDPE): Offers higher stiffness and chemical resistance than LLDPE. Suitable for containers and parts requiring increased rigidity.

• Crosslinked Polyethylene (XLPE): Used when greater structural strength, thermal resistance, or environmental stress crack resistance is needed—commonly used in fuel tanks and industrial applications.

• Nylon (Polyamide): Provides high mechanical strength and heat resistance. It’s ideal for more demanding applications such as automotive and industrial components, though it requires higher molding temperatures.

• Polypropylene (PP): Offers excellent chemical resistance and stiffness. Often used for parts requiring low moisture absorption and dimensional stability.

• Flame-Retardant or UV-Stabilized Grades: Specialty formulations are available for specific performance needs, including fire safety or extended outdoor use.

Each material is selected based on the part’s end-use conditions, including temperature exposure, chemical contact, structural load, and environmental factors. KingStar Mold helps you choose the right resin to balance performance, cost, and production efficiency.

Yes, KingStar Mold specializes in supporting custom rotomolded product development from concept to production. Whether you’re starting with a rough idea, a 2D sketch, or a full 3D model, our engineering team works closely with you to refine the design for optimal moldability, performance, and cost-efficiency.

We provide:

• Design Assistance: Our experts offer input on wall thickness, draft angles, undercuts, parting lines, and material selection to improve manufacturability and product performance.

• Prototyping Options: We can produce initial prototypes through low-volume molding, CNC machining, or 3D printing before full-scale rotomolding, helping you validate fit, function, and aesthetics.

• Tooling Development: Once the design is finalized, we create custom molds tailored to your specific part geometry and production goals.

• Confidentiality and NDAs: We understand the importance of protecting your intellectual property. KingStar Mold is happy to sign non-disclosure agreements (NDAs) upon request to ensure that your designs, concepts, and technical details remain strictly confidential.

Whether you’re developing a new product or improving an existing one, we provide full design-to-delivery support with a strong emphasis on confidentiality, precision, and quality.

At KingStar Mold, quality is built into every step of our rotomolding process. We combine advanced equipment, process control, and rigorous testing to ensure every part we produce meets exact specifications for strength, uniformity, and reliability. Below is an overview of the key quality assurance methods we apply:

1. Leak and Pressure Testing

To ensure every hollow part is fully sealed and leak-proof, we conduct air pressure testing:

• Air Injection: Each part is pressurized to a specified PSI based on its size and application.

• Water Submersion: The pressurized part is submerged in water, and our technicians inspect it for air bubbles, which indicate leaks.

This method is especially crucial for water tanks, coolers, and chemical containers that require absolute airtight integrity.

2. Dimensional Verification

Maintaining consistent part dimensions is essential for proper fit and performance, especially for assemblies and interfacing components.

• In-Process Measurement: We measure production parts, fittings, and sub-assemblies throughout the molding process using calibrated tools.

• Tolerance Checks: Measurements are compared against CAD models or customer specifications to detect any deviation early.

This step ensures that all parts are interchangeable and maintain consistent performance.

3. Internal Air Temperature Monitoring (PIAT)

The rotomolding process relies on precise thermal control. We monitor Peak Internal Air Temperature (PIAT) to ensure proper resin curing.

• Temperature Logging Devices: Sensors placed inside the mold track internal air temperature during each molding cycle.

• Process Validation: The data is used to confirm that the resin reached the optimal temperature range, preventing under- or over-curing.

PIAT monitoring helps guarantee product integrity, surface finish, and mechanical properties.

4. Wall Thickness Mapping

Uniform wall thickness is key to ensuring part strength, load-bearing capacity, and durability.

• Ultrasonic Gauging: We measure wall thickness at multiple critical points using ultrasonic tools.

• Documentation and Mapping: Each part’s wall thickness is mapped and recorded to identify potential weak spots or areas of inconsistency.

By identifying thin or overbuilt areas, we fine-tune the mold and heating cycle for better consistency and performance.

5. Material and Color Uniformity Control

Material properties affect the overall quality of a rotomolded part. We use high-intensity mixers to prepare resin before molding.

• Agglomeration Prevention: The mixer creates shear and heat to prevent clumps, ensuring smooth flow and even melt.

• Color Consistency: The blending process results in polished resin for uniform color distribution and a more attractive surface appearance.

Uniform material flow also helps reduce internal stress, improving the part’s mechanical performance.

6. Foam Filling Quality (if applicable)

For parts requiring insulation, such as coolers, we use polyurethane foam filling systems.

• Controlled Injection: Foam is injected into hollow cavities in measured quantities.

• Expansion and Curing Control: We monitor foam expansion and curing to avoid gaps, ensure even fill, and maximize insulating efficiency.

This step not only boosts thermal performance but also adds structural rigidity.

7. Final Visual and Functional Inspections

Before shipment, each part undergoes a final quality check:

• Surface Inspection: We look for warping, pinholes, sink marks, or surface defects.

• Functional Testing: Hinges, inserts, closures, and other features are tested for usability and fit.

Only parts that pass all inspection points are approved for delivery.

Why Quality Matters at KingStar Mold

Our commitment to quality isn’t just about standards—it’s about trust. Customers across industries count on KingStar Mold for dependable, long-lasting rotomolded parts that perform in real-world applications. From outdoor equipment to insulated containers and automotive components, we ensure every part is built right—every time.

Rotomolding is ideal for producing large, hollow, and seamless plastic parts with complex shapes and consistent wall thickness. Common products include:

• Coolers and Insulated Containers – The hollow design allows for efficient polyurethane foam filling, providing excellent insulation and structural strength.

• Water and Chemical Tanks – Rotomolding produces seamless, corrosion-resistant tanks that can withstand pressure variations and harsh chemicals.

• Kayaks and Small Boats – The ability to mold large, one-piece parts without seams ensures high durability and buoyancy, perfect for marine applications.

• Outdoor Furniture and Playground Equipment – Rotomolded parts resist UV damage, weathering, and impact, making them ideal for outdoor use.

• Automotive Parts (e.g., air ducts, reservoirs) – Lightweight and durable components are easily formed with complex geometries.

• Industrial Housings and Enclosures – The process accommodates thick walls and integrated features, ideal for protective covers and casings.

Rotomolding is particularly suited for low- to medium-volume production where tooling costs need to stay low while maintaining design flexibility and performance.