Additively Manufactured Tool Cores as a Solution for Segmented Cooling Problems in Injection Molding

Segmented tool areas are among the most challenging zones in injection molding. Especially with components that require pronounced rib structures for increased stability, geometrically induced limitations arise in tool cooling. In industrial practice, this often leads to:

• limited or completely absent active cooling,

• inhomogeneous temperature distribution within the segments,

• increased cycle times and

• local hotspots with risks of infiltration or delayed crystallization.
  

Traditionally, attempts have been made to compensate for this problem by using materials with improved thermal conductivity. While such materials initially offer advantages in terms of heat management, their effectiveness is limited in segmented areas because heat dissipation ultimately occurs passively. Additionally, this class of materials often exhibits lower wear and process resistance and disadvantages in machinability – particularly in electrical discharge machining (EDM) and wire EDM.

Thermal challenges in segmented tool areas

With rib or segment geometries, the key challenges lie particularly in heat dissipation. The cooling channels must be routed in a confined space without compromising the structural integrity of the tool. In conventional tools, the cooling channels are therefore often too far from the contour or cannot be positioned at all. This results in temperature gradients and extended cooling times.

This is precisely where the additively manufactured tool core comes in: It enables the implementation of complex channel layouts that would not be feasible with conventional manufacturing.

Additive solution: Tool core with segment-specific cooling routing

Together with Juri Müller and the Addition team, a tooling solution was developed that specifically addresses these limitations: A steel core additively manufactured using the SLM (Selective Laser Melting) process , the design of which provides each individual tool segment with its own active cooling bore .

This concept leads to several process engineering advantages:

1. Uniform cooling directly at the contour

The proximity of the cooling channels to the contouring surface ensures a homogeneous temperature distribution across all segments. Local hotspots are eliminated.

2. Improved thermal reproducibility

Targeted cooling promotes uniform crystallization and thus reduces fluctuations in component properties.

3. Potential for a significant reduction in cooling time

Since the cooling is no longer passive but actively segmented, the cycle time can be significantly reduced in the future.

4. Mechanically stable tool components

Despite the complex channel geometry, the stability of the segment structure is fully maintained.

Manufacturing chain: Additive manufacturing and precise finishing

The blank was printed as a continuous steel component, already equipped with cooling channels, at Addition. The subsequent process steps were carried out entirely at Faust:

• Milling

• Erode

• Grind

• Wire cutting
  

Compared to conventional alternative materials, which can be complex to machine, especially using electrical discharge machining (EDM), the additively produced steel core proved to be significantly easier to machine. This leads to a noticeable reduction in post-processing time and thus to an overall more efficient manufacturing process.

Conclusion: Additive manufacturing as a technological advancement in toolmaking

This project exemplifies the potential of additive manufacturing for complex, thermally demanding tool areas in injection molding. The combination of state-of-the-art additive technology and precise post-processing at Faust results in a tool core that offers clear advantages in terms of both process technology and economics.

Companies struggling with hotspots, long cycle times or critical segment areas benefit from precisely such solutions – individually designed, thermally optimized and reliably manufacturable.

Faust has the experience, network, and manufacturing expertise to effectively solve even complex challenges in toolmaking.