The ExpressTool™ rapid molding process is a revolutionary technique for manufacturing nickel-copper composite shell molds with conformal cooling channels (CCC). This process, developed through collaboration between Hasbro and LaserFare, enables batch production of high-performance molds designed for injection molding. Below, we break down the key steps of the ExpressTool™ process, along with important technical considerations.

1. Prototype Creation and Coating

The first step in the ExpressTool™ molding process is creating a prototype model. The prototype is designed using CAD software, followed by its fabrication using either machining or rapid prototyping techniques. Afterward, a conductive coating is applied to the surface of the prototype. This coating is essential for enabling electroforming during the later stages of the process. Two common methods for coating the prototype include:

1. Silver Nitrate and Reducing Agent Spray: Using a dual-nozzle spray gun, silver nitrate mixed with a reducing agent is sprayed onto the prototype. This method creates a thin, uniform conductive layer (several micrometers thick), which has minimal impact on the prototype’s dimensional accuracy.
2. Silver Paint Coating: A simpler method where a layer of silver paint is applied. However, it’s important to ensure that the coating thickness does not exceed 25 microns to avoid affecting the prototype’s precision.

2. Electroforming Nickel Layer

Once the prototype is coated, it is used as the cathode (negative electrode) in an electroforming process, with nickel serving as the anode (positive electrode). In this step, a nickel shell is electroformed onto the prototype. This electroforming process continues until the nickel shell reaches a thickness of about 2mm. After electroforming, the prototype, now with the nickel shell, is removed from the electroforming tank, rinsed with water, and dried.

3. Conformal Cooling Channel Setup

Conformal cooling channels are a defining feature of the ExpressTool™ process. These cooling channels are added to the backside of the nickel shell, and they are designed to be conformal to the shape of the molded part. Unlike traditional drilled cooling channels, which are limited by the mold’s geometry, conformal cooling channels follow the contours of the part, providing more efficient and uniform cooling.

The main advantage of conformal cooling is that it reduces the temperature difference (ΔT) between different parts of the mold during injection. This leads to more uniform plastic solidification, resulting in less warping and internal stress in the final part. The cooling channels can be bent to conform to the part’s profile, improving cooling efficiency and reducing cycle time by 30% to 50%.

4. Electroforming Copper Layer

Next, the nickel-coated prototype (with conformal cooling channels) is placed into a copper electroplating tank, where a copper layer is electroformed onto the nickel shell. The copper layer serves multiple purposes:

1. Enhanced Heat Transfer: Copper has a much higher thermal conductivity than nickel, allowing heat from the injected plastic to transfer efficiently into the cooling channels.
2. Faster Cooling: The high thermal conductivity of copper significantly reduces the injection cycle time, improving overall production efficiency.
3. Better Temperature Control: Copper acts as an effective temperature control medium, helping to maintain consistent temperatures throughout the mold.
4. Strong Compression Resistance: Copper has a compressive strength of 280–360 MPa, making it durable for use in high-pressure injection molding.
5. Low Thermal Expansion: The coefficient of thermal expansion for copper (16.5×10⁻⁶ K⁻¹) is very similar to that of nickel (13.6×10⁻⁶ K⁻¹), minimizing thermal stresses during molding cycles and preventing cracking or delamination.

5. Adding a Backing Layer

After the electroplated nickel and copper shell with conformal cooling channels is completed, the next step is to apply a backing layer. This backing provides structural support for the mold. The material used for the backing is typically a low-melting-point alloy or filled aluminum epoxy resin, which has good compressive strength and cures quickly (within 4 hours). For high injection pressures (above 70 MPa), steel can be used as the backing material.

6. Prototype Removal

Once the backing layer has cured, the original prototype is removed from the nickel-copper shell. The mold cavity is then securely attached to a mold frame. Holes for ejector pins and the injection ports are drilled into the mold, completing the structure for the injection mold.

7. Final Assembly

The last step involves the assembly of the mold core and the mold frame, completing the injection mold. The mold is now ready for mass production of injection molded parts.

Key Benefits of ExpressTool™

• Improved Cooling Efficiency: The conformal cooling channels reduce the temperature gradient across the mold, resulting in faster and more uniform cooling of the plastic part, reducing cycle time by 30% to 50%.
• Enhanced Mold Life: The combination of nickel and copper provides excellent thermal resistance and strength, significantly increasing the mold’s lifespan and resistance to wear.
• Superior Part Quality: By improving the cooling process, ExpressTool™ molds reduce the warping and internal stress often found in traditionally molded parts, resulting in higher quality and more consistent products.
• Reduced Production Costs: The faster cooling and more efficient manufacturing process reduce production costs and increase throughput.

Conclusion

The ExpressTool™ rapid molding process is a game-changer in the field of injection molding. By using nickel-copper composite shells with conformal cooling channels, this technology significantly improves mold performance, cooling efficiency, and part quality. The detailed and efficient process flow—from prototype creation to final assembly—ensures a high-performance, long-lasting mold suitable for batch production. Whether used for mass production of complex parts or for improving mold cooling efficiency, ExpressTool™ provides a reliable and cost-effective solution for modern manufacturing needs.