Project Update: “Multi-Cool” Investigates Innovative Cooling Processes for Multi-Stage Forming Operations

The two-year “Multi-Cool” research project is investigating ways to make multistage forming processes more robust by integrating active cooling. The goal is to better control unwanted temperature changes during the manufacture of complex sheet metal components, thereby improving process reliability and product quality. In this joint project with FKM Sintertechnik GmbH and the Institute for Production Engineering and Metal Forming Machinery (PtU) at TU Darmstadt, which has been underway since October 2023, Werner Schmid is serving as the consortium leader for the first time.

At the start of the project, heat input during the forming process was determined both experimentally — by inserting thermocouples — and through numerical simulations in order to precisely determine the temperature profiles during the various phases of the forming process. Based on this, the most temperature-critical forming stage was identified and equipped with active tool cooling.

In close collaboration with the project partners, the cooling system shown in the image was developed for the punch and die. Additive manufacturing using selective laser melting (SLM) enables contour-following cooling, which, in the case of the punch, is achieved through 16 individual cooling channels. Compared to conventionally manufactured cooling systems, this offers new degrees of freedom and significantly improves cooling performance. In addition to the design of the cooling system, manufacturability and ease of maintenance are also taken into account.

Another part of the project involves investigating suitable heat treatments and post-processing methods to further optimize the tools’ load-bearing capacity. The initial test results demonstrate the feasibility in principle of additively manufactured tool components and point to promising prospects for their use. While temperatures of up to 120 °C were observed in test series without cooling, the additive-manufactured version — with its significantly higher cooling capacity compared to conventionally manufactured cooling systems — results in more consistent processes and a significant reduction in mold temperature to just 35 °C. We expect this to result in significantly more stable and dimensionally accurate production, which will be validated across a larger number of stages in the next series of tests.

This project (HA Project No.: 1482/23-35) is funded as part of the Hesse Innovation Promotion Program with funds from LOEWE – Landes-Offensive zur Entwicklung Wissenschaftlich-ökonomischer Exzellenz, Förderlinie 3: KMU-Verbundvorhaben.