The DirectTool™ process utilizes advanced metal alloy powders for creating high-performance molds using Selective Laser Sintering (SLS) technology. Two commonly used alloy powders in the DirectTool™ process are DirectMetal Copper-Nickel Hybrid Powder and DirectSteel Steel-Bronze-Nickel Hybrid Powder. These materials are specifically designed to meet the rigorous demands of rapid mold production, offering both durability and precision.

1. DirectMetal Copper-Nickel Hybrid Powder

The DirectMetal Copper-Nickel Hybrid Powder is a composite material developed by Electrolux, a Swedish company. It consists of a blend of bronze and nickel alloys, with the following composition:

• 75% Bronze (90% Copper, 10% Tin)
• 20% Nickel
• 5% Phosphor Bronze

The average particle size of the powder ranges from 35 to 40 micrometers.

Process and Properties

• During the Selective Laser Sintering (SLS) process, the alloy powder undergoes a phase transition, which leads to volume expansion that compensates for shrinkage during sintering. As a result, even if the sintered metal mold does not experience significant dimensional shrinkage, it still retains over 20% porosity.
• After the sintering process, it is essential to perform a penetration treatment to remove the porosity. Typically, this involves infiltrating the mold with low-melting metals (like tin) or high-temperature epoxy resins, which help to close the pores and enhance the mold’s strength and durability.
• The mechanical properties of the material are enhanced after the infiltration step, resulting in a tensile strength of 150 MPa and bending strength of 300 MPa before post-treatment. After the infiltration process, the bending strength increases to 400 MPa, with an improved surface finish (roughness Ra=3.5 µm), and hardness reaching 108 HBW. Additionally, the thermal conductivity reaches 110 W/(m·K).
• The process achieves high accuracy, with a mold precision range of 0.05% to 0.1%, ensuring high-quality mold production suitable for injection molding and die-casting applications.

Infiltration Process

The infiltration process takes advantage of capillary action. The semi-finished part is immersed in resin for about 30 minutes and then placed in an oven at 160°C for curing. This post-processing step ensures that the mold remains dimensionally accurate while improving its mechanical properties.

2. DirectSteel Steel-Bronze-Nickel Hybrid Powder

DirectSteel Steel-Bronze-Nickel Hybrid Powder is another popular material used in the DirectTool™ process, and it comes in several variations: 50-V1, 50-V2, and 100-V3. This alloy powder does not contain any organic components, and its particle size is typically around 50 micrometers.

Characteristics of DirectSteel Alloys

• 50-V1 Grade: This alloy is particularly suited for high-strength applications, with a tensile strength of 500 MPa and a hardness range of 60-80 HBW. Molds made from this powder can last through thousands of injection cycles and hundreds of die-casting cycles without noticeable wear. When surface treatments like nickel plating (10-30 µm thick) are applied, the hardness increases to 512 HV, equivalent to that of hardened steel, further enhancing the mold’s durability.
• 50-V2 Grade: This alloy is used for producing small batch functional prototypes. Molds made with 50-V2 exhibit excellent mechanical properties, along with outstanding precision and surface finish, making them ideal for rapid prototyping and small-volume production.
• 100-V3 Grade: The 100-V3 alloy powder is designed for quick sintering and produces steel-based molds with high mechanical strength, excellent precision, and great internal structure. This material is particularly beneficial for high-precision applications and provides strong, durable molds for injection molding and die-casting.

Benefits of DirectSteel Alloys

• No Post-Sintering or Infiltration Required: Unlike the DirectMetal Copper-Nickel Hybrid Powder, DirectSteel alloys do not require infiltration with additional materials such as copper, tin, or resins. The sintered molds are ready for use in applications like injection molding and die-casting.
• High Precision and Quality: DirectSteel powders offer high precision in the sintering process, leading to molds with excellent dimensional accuracy and surface quality.
• Longer Mold Life: The 50-V1 and 50-V2 grades, in particular, are known for their extended mold life, making them ideal for industries that require high-volume production, such as automotive and electronics.

Conclusion

The DirectTool™ process utilizes advanced metal alloy powders to produce high-performance, durable molds for rapid manufacturing. The DirectMetal Copper-Nickel Hybrid Powder offers superior precision and enhanced mechanical properties after infiltration, making it ideal for molds used in injection molding and die-casting. Meanwhile, the DirectSteel Steel-Bronze-Nickel Hybrid Powder offers outstanding mechanical strength, high precision, and long mold life, all without the need for post-sintering or infiltration. Both materials provide the flexibility and performance needed for high-quality, cost-effective rapid tooling solutions across a variety of industries.