8L Plastic Paint Bucket Mold
Professional Definition:
Refers to an injection mold used for producing 8-liter plastic packaging buckets for industrial paints. It represents a technically demanding, structurally complex, and highly stable key piece of equipment in the paint packaging industry.
Core Technical Features
Technical Parameter | Detailed Specification |
|---|
Mold Structure | Hot runner + Cold runner composite system |
Number of Cavities | 1-2 cavities (single cavity primarily) |
Mold Weight | 3.5-5 tons |
Injection Machine Requirement | 800-1200 tons clamping force |
Shot Weight | 800-1200g |
Molding Cycle | 40-60 seconds |
Daily Output | 1200-1800 pieces (24 hours) |
Innovative Mold Structure Design
1. Multi-layer Composite Bucket Wall Molding Technology
Bucket body structure: - Outer layer: Thickness 1.8-2.2mm, high-gloss surface - Middle layer: Foam layer, thickness 0.5-0.8mm, provides heat and sound insulation - Inner layer: Thickness 0.6-0.9mm, chemical-resistant coating - Reinforcement ribs: Ring + longitudinal composite ribs, height 4-6mm - Bottom anti-slip pattern: Depth 0.8-1.2mm
2. Integrated Handle Simultaneous Molding
Handle structure: - Material: PP+TPE composite injection molding - Molding method: In-mold assembly rotational molding - Rotation shaft: Diameter Φ8mm, includes self-lubricating bearing structure - Locking mechanism: Ratchet-type self-locking, opening torque 2-3N·m - Strength test: Load-bearing capacity ≥25kg
3. Dual Sealing Lip Design
Sealing system: ├─ Primary seal: 3mm wide sealing lip, interference fit 0.4-0.6mm ├─ Secondary seal: 2mm wide auxiliary lip, inclination angle 15° ├─ Tamper-evident ring: 0.3mm connecting rib, breaking force 30-40N └─ Threads: M65×4 trapezoidal threads, 4 complete thread turns
Runner and Cooling System
1. Multi-stage Hot Runner System
Runner configuration: ├─ Primary distribution: Center gate, diameter Φ20-25mm ├─ Secondary distribution: 4-point symmetrical, diameter Φ12-15mm ├─ Tertiary distribution: 8-point annular, diameter Φ8-10mm └─ Gate design: Submarine + Direct gate compositeTemperature control: Zoned independent, temperature difference ≤±2℃
2. Layered Cooling Design
Cooling circuits: ├─ Barrel cooling: 6 spiral water channels, Φ12mm ├─ Bottom cooling: Cross water channels, Φ10mm ├─ Neck cooling: Annular water channel + bubbler tube ├─ Handle area: Independent rapid cooling └─ Gate area: Beryllium copper insert enhanced coolingTotal flow rate: 60-80 L/min
Mold Materials and Processes
Component | Material Grade | Hardness | Special Treatment |
|---|
Cavity | 1.2738HH | 32-36 HRC | Hard chrome plating + Nano-coating |
Core | 1.2344 ESR | 48-52 HRC | Deep nitriding |
Thread inserts | Powder high-speed steel | 60-63 HRC | Diamond-like carbon coating |
Hot runner | High-temperature alloy | 40-45 HRC | Ceramic insulation |
Ejector pins | SKD61 | 54-58 HRC | Titanium plating |
Production Process Control
1. Multi-stage Injection Parameters
Injection process: ├─ Stage 1: Low-speed bottom filling (20-30 mm/s) ├─ Stage 2: Medium-speed barrel filling (40-50 mm/s) ├─ Stage 3: High-speed neck filling (60-70 mm/s) ├─ Stage 4: Low-speed handle filling (15-20 mm/s) └─ Holding pressure: 5-stage decreasing pressureInjection pressure: 100-140 MPaMelt temperature: 200-230°C (for PP)
2. Post-molding Processing
Post-demolding treatment: - Stress relief annealing: 80-90°C, 2-3 hours - Neck sizing: Hydraulic neck expansion to ensure roundness - Seal testing: 0.05 MPa air pressure test - Stacking inspection: 5-layer stacking stability
Quality Control Standards
1. Dimensional Accuracy Requirements
Key dimension tolerances: ├─ Capacity: 8L ±0.1L ├─ Height: 285-295mm ±1mm ├─ Diameter: Φ240-250mm ±0.5mm ├─ Wall thickness: 2.5-3.5mm ±0.2mm ├─ Thread accuracy: Class 6g └─ Flatness: ≤0.3mm/300mm
2. Performance Testing Items
Mechanical performance tests: - Drop test: 1.2m height, 3 orientations - Stacking test: ≥300kg, 24 hours - Seal test: 0.03 MPa, 30 minutes - Handle strength: 25kg load, 1000 cycles - Chemical resistance: 30-day immersion test
Mold Maintenance
1. Daily Maintenance Points
Maintenance Item | Frequency---|---Clean parting surface | Every cycleCheck hot runner | Every 4 hoursLubricate moving parts | Per shiftCheck cooling water | DailyRecord data | Every cycle
2. Regular Maintenance Schedule
Maintenance schedule: ┌─ Every 10,000 cycles: Check seals ├─ Every 30,000 cycles: Inspect cavity dimensions ├─ Every 50,000 cycles: Replace wear parts ├─ Every 100,000 cycles: Hot runner maintenance └─ Every 200,000 cycles: Complete overhaul
Innovation Highlights
1. Anti-sediment Structure Design
Bottom taper: 5-8° inclination for easy paint outflow
Inner wall streamlined design: Reduces paint residue
Anti-settling ribs: 3-4 flow-guiding ribs to prevent pigment settling
2. Anti-counterfeiting and Traceability System
Laser engraving area: Production batch number, date
RFID implant slot: Electronic tag embedding
Anti-counterfeiting texture: Special anti-counterfeiting marks on bucket bottom
3. Environmental Design
Wall thickness optimization: Weight reduction 10-15%
Monomaterial: Facilitates recycling
Quick cleaning: Special inner wall treatment
Production Efficiency and Cost
Economic Indicator | Value Range | Industry Comparison |
|---|
Mold Investment | 250,000-400,000 RMB | Medium to high |
Material Cost per Piece | 4-6 RMB | 8% reduction |
Production Cycle | 45-55 seconds | 15% improvement |
Qualification Rate | ≥99% | 1% improvement |
Energy Consumption per Piece | 0.8-1.2 kWh | 20% reduction |
Mold Life | 500,000-800,000 cycles | 30% extension |
Application Scenarios Expansion
Industrial Paint Packaging
Architectural paints
Automotive paints
Marine paints
Anti-corrosion paints
Special Liquid Packaging
Customized Requirements
Technology Development Trends
Lightweight Direction
Wall thickness reduction to 2.0-2.5mm
Microcellular foaming technology application
Structural topology optimization
Functional Integration
Integrated metering devices
Intelligent liquid level indication
Temperature and humidity sensing
Green Manufacturing
Industry Value: The 8L plastic paint bucket mold is a critical link connecting paint manufacturing and end-use applications. Its technological level directly impacts packaging safety, transportation economics, and usage convenience. As industrial paints evolve towards environmental friendliness, functionality, and premiumization, this mold technology is rapidly advancing towards lightweight high strength, intelligent anti-counterfeiting, and green sustainability, becoming a crucial technological pillar driving the upgrading of the paint packaging industry.