Plastic Bucket Mould Supplier

A plastic paint bucket mold is an injection mold used for the mass production of plastic paint buckets, coating buckets, or chemical buckets. Molten plastic is injected into the mold cavity using an injection molding machine, and after cooling and solidification, a bucket body with a certain strength and sealing performance is obtained.

Common products include:

• 1L–5L small paint buckets
• 10L–20L medium paint buckets
• 20L and above industrial plastic buckets
• Structural Design Considerations

The bucket wall is usually designed with uniform thickness.

The bottom and reinforcing rib areas require special reinforcement.

High precision is required for the bucket opening position, affecting the sealing performance of the lid.

Commonly Used Materials and Mold Steel

Plastic Materials

PP (Polypropylene): Widely used, moderate cost, good toughness

HDPE (High-Density Polyethylene): Good impact resistance and chemical resistance

Mold Steel

• P20: Commonly used for medium-volume molds
• 718 / 718H: Good stability, suitable for long-term production.
• H13: Suitable for high-volume and high-requirement molds.

Injection Molding Process and Production Characteristics

• Molding Cycle: Generally 30–60 seconds, depending on barrel size.
• High Cooling Requirements: Due to the thicker barrel, the cooling system design is particularly critical.
• Deformation Control: Requires a reasonable cooling and demolding solution.
• High Degree of Automation: Often used in conjunction with robotic arms for automatic part removal.

What are the key design requirements for a plastic paint bucket mould?

• Material selection: Paint buckets are usually made from HDPE or PP because these materials offer chemical resistance and durability. The chosen material affects wall thickness, cooling requirements, and gate design.
• Wall thickness and reinforcement: The bucket must withstand stacking and handling. Uniform wall thickness and properly placed ribs help maintain strength without excessive material use.
• Handle and rim design: The mould must include features for a stable handle attachment and a strong rim that can support lifting. These details influence the mould structure and ejection system.
• Surface finish: Paint buckets often require a smooth exterior to allow labels to adhere. The mould surface needs to be finished accordingly to reduce post-processing.

What are common issues in paint bucket moulding and how can they be managed?

• Warping and distortion: Uneven cooling can bring about warping. Balanced cooling channels and consistent processing parameters help reduce this issue.
• Sink marks and surface defects: High packing pressure or insufficient cooling time can cause sink marks. Adjusting packing profiles and ensuring proper wall thickness can help.
• Sticking or difficult ejection: Improper draft angles or inadequate ejector placement can cause sticking. Ensuring proper draft and a well-designed ejector system can reduce ejection problems.
• Runner and gate waste: Excessive runner material increases cost. Optimizing runner design and considering hot runner systems can reduce waste.

How should a plastic bucket mold be designed for high-volume production?

• Multi-cavity layout: A multi-cavity mold increases output but requires careful balance of runners and cooling to ensure consistent quality across cavities.
• Cooling system optimization: Uniform cooling reduces cycle time and maintains dimensional accuracy. Cooling channels should be designed to avoid hotspots and uneven shrinkage.
• Gate and runner system: The gate location affects filling balance and weld lines. A well-designed runner system supports uniform flow and reduces pressure drop.
• Durability and maintenance: For high-volume runs, the mold must withstand repeated cycles. Selecting appropriate mold steel and planning maintenance schedules can improve long-term performance.

What factors influence the choice between hot runner and cold runner systems for bucket molds?

• Material and product size: Hot runner systems reduce runner waste and can be effective for large or thick-walled buckets. Cold runner systems are simpler and may be suitable for smaller or lower-volume production.
• Initial cost vs long-term savings: Hot runner systems typically have higher initial costs but can reduce material waste and improve cycle time. Cold runner systems may be less expensive upfront but generate more runner scrap.
• Process stability: Hot runner systems require precise temperature control. Cold runner systems are easier to maintain but may have longer cycle times due to runner cooling.
• Maintenance requirements: Hot runner systems may require specialized maintenance and temperature control components. Cold runner systems have fewer components and can be easier to service.

This structure covers key considerations for plastic paint bucket moulds and plastic bucket molds, addressing common design and production questions in a clear and practical format.