Advantages and Disadvantages of Copper Molds
Excellent Thermal Conductivity
Copper's thermal conductivity (approximately 380-401 W/(m・K)) is much higher than that of aluminum alloys (approximately 100-230 W/(m・K)). It can quickly transfer heat within the mold, making it suitable for applications requiring rapid heat dissipation. For example:
Hot runner inserts and localized cooling components for cores/cavities in injection molds can shorten molding cycles (e.g., for thin-walled plastic parts and precision parts);
Localized inserts in high-risk areas of die-casting molds prevent workpiece deformation due to excessive temperatures.
Excellent Electrical Conductivity
Some specialized molds (e.g., EDM electrodes and electromagnetic forming molds) require high electrical conductivity, making copper (especially red copper and chromium copper) the preferred material.
Good Toughness and Strong Fatigue Resistance
After aging treatment, beryllium copper can reach strengths exceeding 1000 MPa. Its toughness is superior to some aluminum alloys, making it suitable for applications subject to repeated impact but low loads (e.g., localized inserts in small stamping dies). Disadvantages: Low hardness and poor wear resistance. Copper's hardness (beryllium copper is approximately 30-45 HRC, while red copper is only 30-40 HB) is much lower than that of high-strength aluminum alloys (such as 7075 aluminum alloy, which can reach 150-180 HB, approximately 12-15 HRC). It is susceptible to wear and deformation when subjected to long-term friction or high pressure, resulting in a shorter lifespan.
It is not suitable for high-load molds (such as thick plate stamping and large die-casting molds).
High cost and high density: Copper (especially beryllium copper) is typically 3-5 times more expensive than aluminum alloys, and its density (8.9 g/cm³) is more than three times that of aluminum alloys (2.7 g/cm³). It is not suitable for large molds (as it increases equipment load and costs).
High processing difficulty: Copper's high ductility makes it prone to "sticking" during cutting, causing significant tool wear. Its efficiency in machining complex shapes is lower than that of aluminum alloys.