How Thermal Conductivity Drives Mold Efficiency

Thermal conductivity plays a key role in mold manufacturing, especially for industries requiring quick and efficient production cycles. High thermal conductivity allows faster cooling, which shortens production cycles and enhances efficiency.

In response, mold makers incorporate materials such as Thermodur 2383 and Moldmax HH, known for their superior thermal conductivity, wear resistance, and stability under high temperatures.

You can also read: 3 Tips for Cooling Design in Injection Molding

The Big Picture

In injection mold production, materials with high thermal conductivity, ranging from 15 W/mK to over 150 W/mK, help dissipate heat quickly, thereby reducing cycle time. However, such high-conductivity materials often have lower mechanical strength, making them less suitable for processing reinforced polymers. As a result, manufacturers often consider mold steels with a more moderate thermal conductivity range (40 W/mK to 65 W/mK), as these materials offer a better balance between heat dissipation and structural strength.

Thermal conductivity through temperature change of five metal alloys. Courtesy PM Tec Engineering

Despite their advantages, high-conductivity mold steels are priced significantly higher, leading to industry hesitation. In some cases they reach up seven times the cost of conventional options. To assess the actual value of these materials, a study compared the cycle times and part quality between high thermal conductivity mold steel and traditional mold steel.

For manufacturers working with semicrystalline thermoplastics like polyamide, researchs found that the material’s thermal conductivity had a minimal impact on part properties, indicating that investing in high-conductivity mold steel might yield minimal improvements in part quality for certain materials. Therefore, a detailed cost analysis considering mold expenses and cycle time is essential before choosing a high-conductivity material. For this the simulation can help to take the decision easer quantifying the cost-benefit rate of all options.

The Case Study

A key advantage of high-conductivity materials is their ability to maintain uniform surface temperatures, even in narrow mold sections where water cooling may be challenging. Through simulations, thermal conductivity performance across different materials has been tested, allowing manufacturers to visualize and quantify thermal behavior in multi-cycle experiments. For instance, a virtual thermocouple might be placed on mold surfaces to monitor thermal distribution. This reveals significant temperature differences across alloy types.

Comparison Cycle 21 of 5 alloys cavity temperature (left) and estimated solidification time (right) for each. Courtesy PM Tec Engineering

For manufacturers focusing on minimizing cycle time, the choice of a high-conductivity alloy can be game-changing. Alloys like Moldmax HH, which exhibit both excellent conductivity and thermal stability, stand out for applications demanding swift heat dissipation. These materials support the efficiency and quality of the production process, which is critical when high-volume outputs are necessary.

Wrapping-up

Selecting alloys with optimal thermal conductivity is essential for manufacturers aiming to streamline their production cycles. Thermodur 2383 and Moldmax HH offer enhanced performance, maintaining consistent temperatures and improving the overall efficiency of the mold-making process. However, to further boost mold longevity, effective surface hardening techniques are essential. In the next article, we’ll explore how surface hardening can extend mold life and improve performance.

To read more: Optimization of heat transfer in injection molds and its impact on process efficiency and part quality