Core Characteristics and Applications of Aluminum Alloy Molds
Common aluminum alloys used for molds include 7075, 6061, and 5052. Their core advantages are high strength, low cost, and lightweight, making them suitable for applications requiring high mechanical properties and economic efficiency.
Advantages
Balanced Strength and Hardness
7075 aluminum alloy (after heat treatment) has a tensile strength of 500-570 MPa and a hardness of approximately 150-180 HB. It can withstand high loads and is suitable for high-pressure molds (such as stamping dies, die-casting mold bases, and large injection molds).
6061 aluminum alloy has excellent processability (easily cut and welded), making it suitable for complex-shaped molds (such as automotive panel thermoforming dies and blow molding molds). Anodizing can also increase surface hardness (enhancing wear resistance). Lightweight and Low Cost
Aluminum alloy has a density of only 2.7 g/cm³, one-third that of copper. This makes it suitable for large molds (such as automobile bumper injection molds and container stamping molds), reducing the weight of the equipment. Its price is typically only one-third to one-fifth that of copper, offering significant cost advantages in mass production.
High Processing Efficiency
Aluminum alloy offers low cutting resistance and can be milled at high speeds (feed speeds 1.5-2 times that of copper). It is suitable for machining complex cavities (such as toy molds and appliance housing molds), shortening production cycles.
Disadvantages
Weaker thermal conductivity than copper. While superior to steel (approximately 45 W/(m・K)), it dissipates heat more quickly than copper, making it unsuitable for applications requiring extreme cooling efficiency (such as precision micro-plastic molds and rapid prototyping of thin-walled parts). Limited Heat Resistance: Aluminum alloys gradually soften above 120-150°C (the upper limit of 7075's heat resistance is approximately 120°C), making them unsuitable for high-temperature environments (such as the high-temperature cavity of a die-casting mold, which often operates at temperatures exceeding 300°C and requires heat-resistant steel).