Technical Specifications for Paint Bucket Molds
Paint bucket molds are professional injection molding equipment used to produce plastic paint buckets with handles. Their technical core lies in the balanced optimization of sealing structure, handle strength, and production efficiency.
I. Product Specification System
1. Standard Capacity Series
Capacity Specification | Dimensions | Opening Diameter | Wall Thickness | Handle Structure | Applicable Paint Type |
|---|
1-liter bucket | Φ120×160mm | Φ60mm | 1.8-2.0mm | Integral handle | Small package paints |
4-liter bucket | Φ190×220mm | Φ85mm | 2.0-2.2mm | Arch handle | Household latex paint |
18-liter bucket | Φ285×320mm | Φ100mm | 2.3-2.5mm | Reinforced handle | Construction paint |
20-liter bucket | Φ295×330mm | Φ100mm | 2.3-2.5mm | Dual handles | Industrial paint |
2. Sealing Structure Types
Threaded Seal: 60° trapezoidal thread, pitch 4-5mm
Snap-fit Seal: Three-point snap fit, interference 0.3-0.5mm
Press-in Seal: Flat seal + rubber gasket
Tamper-evident Seal: One-time tear ring structure
II. Mold Design Key Points
1. Handle Structure Design
Handle Molding System:Integral Handle├── Arch height: 40-60mm├── Cross-section: Oval 20×12mm├── Connection points: Gradual transition R8-R10└── Internal reinforcement: Cross-rib structureFoldable Handle├── Hinge thickness: 1.2-1.5mm├── Movement clearance: 0.3-0.4mm├── Positioning structure: Male-female配合└── Fatigue life: ≥5000 cyclesDual Handle Structure├── Symmetrical arrangement: Spacing 120-150mm├── Load distribution: 50% each└── Synchronized action: Simultaneous folding
2. Mold Structure Configuration
Cavity Layout:
1-4 liter buckets: 1×4 or 1×6
10-20 liter buckets: 1×2 or 1×3
Special specifications: 1×1
Core-pull Mechanisms:
Handle slides: Hydraulic or angle pin driven
Thread unscrewing: Gear rack demolding
Snap-fit slides: Delayed core pull design
Guidance system: Carbide guide bushings
III. Materials and Processes
1. Material Selection Standards
Material Type | Melt Flow Rate | Density | Tensile Strength | Chemical Resistance | Applicable Products |
|---|
HDPE | 4-7g/10min | 0.95-0.96 | ≥22MPa | Excellent | General paint buckets |
Copolymer PP | 8-12g/10min | 0.90-0.91 | ≥25MPa | Good | Water-based paint buckets |
LLDPE | 2-4g/10min | 0.92-0.93 | ≥20MPa | Excellent | Impact resistant buckets |
Modified PP | 10-15g/10min | 0.92-0.94 | ≥28MPa | Good | High-gloss buckets |
2. Injection Molding Parameters
Temperature Control:
Barrel temperature: 190-220℃
Mold temperature: 40-60℃
Hot runner temperature: 210-230℃
Handle area: Special temperature control
Pressure Parameters:
Injection pressure: 80-120 MPa
Packing pressure: 60-90 MPa
Back pressure: 5-10 MPa
Clamping force: 500-1500 tons
Time Control:
Injection time: 5-10 seconds
Packing time: 15-25 seconds
Cooling time: 25-40 seconds
Core-pull time: 2-4 seconds
Total cycle: 50-85 seconds
IV. Sealing System Design
1. Bucket Opening Seal Structure
Threaded Seal System:60° Trapezoidal Thread├── Pitch: 4-5mm├── Thread height: 1.5-2.0mm├── Fit clearance: 0.1-0.2mm└── Gasket groove: 2.0×2.0mmSnap-fit Seal System:Three-point Snap Fit├── Snap height: 3-4mm├── Snap angle: 15-20°├── Interference: 0.3-0.5mm└── Opening force: 20-30NPress-in Seal:Flat Seal Structure├── Seal surface width: 3-4mm├── Flatness: ≤0.05mm├── Rubber groove: 3×3mm└── Compression: 20-30%
2. Mold Implementation Solutions
Thread Molding: Rotating demolding or slide molding
Snap-fit Molding: Slides + delayed ejection
Sealing Surface: Mirror polish Ra ≤0.2μm
Venting System: Vacuum assisted venting
V. Quality Inspection Standards
1. Dimensional Accuracy Requirements
Inspection Item | Tolerance Standard | Inspection Method | Frequency |
|---|
Capacity Error | ±2% | Water volume method | Each batch |
Opening Diameter | ±0.2mm | Go/no-go gauge | Every 2 hours |
Wall Thickness Uniformity | ±0.2mm | Ultrasonic | Every 4 hours |
Seal Surface Flatness | ≤0.1mm | Surface plate + feeler gauge | Each batch |
Handle Position | ±1.0mm | Projector | Each batch |
2. Performance Test Items
Seal Test:
Load-bearing Test:
Drop Test:
Drop height: 1.2m
Drop angles: Corner, edge, face
Test temperature: -10℃
Requirements: No leakage, no cracking
VI. Production Efficiency Control
1. Production Cycle Optimization
Capacity Specification | Cavities | Cycle Time | Daily Output | Yield Target |
|---|
1-4 liter buckets | 1-4 | 45-55 seconds | 9,000-11,000 | ≥99% |
10 liter bucket | 1-2 | 55-65 seconds | 5,500-6,500 | ≥98.5% |
18-20 liter buckets | 1-2 | 70-85 seconds | 2,000-2,400 | ≥98% |
Special buckets | 1 | 80-100 seconds | 850-1,000 | ≥97.5% |
2. Automation Configuration
Robot part removal: 3-5 seconds/cycle
Automatic degating: Online cutting
Vision inspection: 100% seal surface check
Automatic stacking: Robotic palletizing
Online weighing: Weight sorting
VII. Mold Maintenance
1. Daily Maintenance
Per Shift Checks:
Daily Maintenance:
2. Periodic Maintenance
Maintenance Item | Maintenance Interval | Work Content | Standard Requirements |
|---|
Slide System | 10,000 cycles | Clean, inspect, lubricate | Smooth movement |
Thread Mechanism | 20,000 cycles | Wear check, clearance adjustment | Fit accuracy |
Hot Runner | 30,000 cycles | Temperature calibration, seal inspection | Temperature difference ≤2℃ |
Cooling System | 50,000 cycles | Chemical cleaning, flow rate inspection | Flow rate ≥95% |
Complete Overhaul | 100,000 cycles | Accuracy restoration, component replacement | Restore 90% accuracy |
VIII. Special Function Design
1. Anti-counterfeiting Structures
Tamper-evident ring: One-time tear design
Anti-backflow: Check valve structure
Marking area: Laser engraving position
Traceability code: In-mold engraving structure
2. Ergonomic Design
Grip optimization: Ergonomic handle
Anti-slip design: Bucket body non-slip texture
Stacking structure: Automatic positioning bosses
Handling assistance: Grip grooves or depressions
3. Environmental Design
Lightweighting: Wall thickness optimization
Easy recycling: Single material
Reusable: Durable structure
Easy cleaning: Smooth inner walls
Technical Characteristics: Paint bucket molds achieve high-quality, high-efficiency production of paint packaging containers through precise sealing structure design, reliable handle molding systems, and efficient production process control. Mold design must comprehensively consider sealing performance, load-bearing strength, operational convenience, and production costs. By optimizing core-pull mechanisms, cooling systems, and automation interfaces, the product is ensured to maintain long-term stable use in demanding chemical storage environments.
