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Views: 0 Author: Site Editor Publish Time: 2025-05-30 Origin: Site
| Table of Contents |
| 1. What is Two color Molding |
| 2. What is Overmolding |
| 3. Process and Equipment Differences |
| 4. Structural Design Key Points |
| 5. Material and Cost Analysis |
| 6. Application Scenario Recommendations |
| 7. Demonstration of Enterprise Technical Advantages (Case Studies) |
What is Two color Molding: A process where two plastic materials are injected sequentially in the same injection molding machine, forming a single product in one molding cycle. Typically requires a specialized two color injection molding machine and a single integrated injection mold.
What is Overmolding: A process where two plastic materials are molded separately using two independent molds. The first molded part (hard substrate) is manually or mechanically transferred to a second mold for soft material encapsulation. Does not require specialized two color molding equipment.
· First Injection: Hard material (e.g., ABS/PC) injected via the first nozzle.
· In-Mold Transition: Rear mold rotates 180° or slides horizontally to align with the second injection station.
· Second Injection: Soft material (e.g., TPU/TPE) injected to form a composite structure.
Key Principles:
1. Hard plastic material first, soft plastic material second.
2. Transparent material first, opaque material second.
3. Higher-melting-point material first, lower-melting-point material second.
· Step 1: Hard substrate injection molded in a standard injection molding machine.
· Step 2: Substrate transferred to a second mold for soft material encapsulation.
Comparison Dimension | Two color Molding | Overmolding |
Injection Machine Type | Dedicated two color injection molding machine (dual barrels + dual nozzles) | Standard single color plastic injection molding machine (single barrel + single nozzle) |
Mold Structure | Integrated design (1 set of plastic injection mold) with rotating/sliding mechanisms | Two independent plastic injection molds without linkage mechanisms |
Control System | Requires synchronized control of dual injection parameters (±2°C temperature accuracy) | Independent control of two injection processes; no synchronization required |
Automation Level | Fully automated (≥90% robotic integration) | Semi-automated (relies on manual substrate transfer) |
Energy Efficiency | Lower energy consumption per unit (one machine completes both processes) | Higher energy consumption (two independent machines operate separately) |
4. Structural Design Differences
Design Dimension | Two color Molding | Overmolding |
Mold Symmetry | Requires 180° rotational symmetry structure | Two independent plastic injection molds, no symmetry requirement |
Substrate Handling | Automatic in-mold positioning (no transfer) | Manual/robotic transfer with external alignment |
Gate Complexity | Dual gate systems (hot runner preferred) | Single gate design with anti-stick features |
two color molding machine
injection molding machine
· Two color Molding:
· Hard materials: High-temperature-resistant (ABS, PC) with ≥20°C higher melting points.
· Soft materials: TPE/TPU with chemical/mechanical bonding compatibility.
· Overmolding:
· Hard substrates: Recyclable materials (e.g., ABS regrind) with surface treatments (texturing/flame treatment).
· Soft encapsulation: Mechanical interlock designs (e.g., undercuts) for adhesion.
Comparison Dimension | Two color Molding | Overmolding |
Initial Investment | 2–3× higher cost for specialized two color injection molding machines; mold complexity increases costs by 30–50%. | Standard machines suffice (lower equipment cost); two simpler independent plastic injection molds required. |
Mass Production Efficiency | 30% shorter cycle time; ideal for high-volume molding orders (≥100k units), reducing long-term costs by 20–30%. | 30–50% longer cycle time due to dual processes; manual substrate transfer increases labor costs. |
Material Waste | 7% lower waste; automation minimizes defects. | Higher scrap rates due to substrate damage during transfer. |
Labor & Maintenance | High automation (≥90% robotic integration); labor costs <10%. | Labor-intensive substrate transfer (40% labor cost); lower mold maintenance frequency. |
Applicable Cost Scenarios | High-precision, high-volume molding orders (e.g., automotive buttons, dual-color lamp housings); high upfront costs amortized via scale. | Low-volume molding customization (e.g., medical device handles), experimental R&D; avoids equipment idle risks. |
· High-Precision Electronics: Dual-color seals, smartphone plastic housings.
· Automotive Plastic Parts: Two-tone lamp covers, wear-resistant handles.
· Consumer Durables: Ergonomic tool grips with anti-slip layers.
· Low-Volume Molding Customization: Medical device handles, experimental prototypes.
· Complex Functional Parts: Multi-angle automotive interiors with mechanical interlocks.
Dimension | Two color Molding | Overmolding |
Production Volume | Suitable for stable orders ≥100k units/year | Ideal for small batches ≤10k units/year |
Precision Requirements | High-precision bonding (tolerance ≤0.1mm) | Accepts ±0.3mm tolerance for general industrial parts |
Material Compatibility | Requires ≥20°C melting point difference + thermal bonding | Handles incompatible materials via mechanical interlocks |
Cost Sensitivity | High initial equipment investment (≈2-3× standard) | Lower equipment costs, ideal for budget-constrained projects |
Requirements:
Innovations:
· 180° Rotating Mold Design:
Utilizes a two color injection molding machine (HAITIAN MA2600Ⅱ) with a rotating core mold, achieving seamless dual-material alignment (tolerance ≤0.02mm) to ensure precision on sealing surfaces.
· Gate Optimization:
· First color: Submarine gate (diameter 0.8mm) minimizes gate marks.
· Second color: Fan gate eliminates weld lines and enhances TPE filling efficiency.
· Temperature Synchronization Technology:
Independently controls nozzle temperatures (280℃ for PA6-GF15 vs. 220℃ for TPE) to prevent thermal degradation.
· Automated Production:
Integrated robotic handling system achieves 99.3% yield rate and reduces cycle time to 35 seconds per piece.
Results:
· Performance Achievement: The customer expressed high satisfaction with the product sample quality after evaluation.
· Cost Optimization: Achieved a 28% cost reduction compared to traditional overmolding processes after producing 100,000 units (driven by 15% equipment efficiency improvement and 7% reduction in material waste).
two color product
two color mold
Requirements:
1. Functional positioning: Industrial-grade controller operating panel requiring IP54 protection rating and high-frequency operation durability.
2. Rigid material: PC-203 (high-temperature-resistant polycarbonate, melting point 260-280°C).
3. Soft material: TPE-70A (Shore hardness 70A, aging-resistant TPE material, melting point 190°C).
Innovations:
· Infrared Positioning System: Ensures substrate transfer accuracy of ±0.05mm, critical for sealing surface alignment.
· Closed-Loop Injection Pressure Control: Maintains TPE thickness uniformity with ±1.5MPa pressure tolerance, eliminating flow imbalance defects.
· 100% Recycled Rigid Sprue Material: Reduces raw material costs by 22% via in-process regrind reuse (qualified for non-critical structural areas).
· Standardized Positioning Fixtures: Enable 5-minute mold changeover across multiple panel models, cutting downtime by 40%.
Results: This case has been successfully applied to electronic control systems, with a cumulative mass production of 500,000 pieces, and customers are very satisfied
overmolding product
overmolding mold
Alpine Mold was founded in 2002 and is a high-tech enterprise integrating engineering design, injection mold manufacturing, small and large batch injection molding services. We focus on providing urgent, difficult and high-precision plastic manufacturing solutions for various industries.
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