Fully automated 2K tool for 384-well plate modules with pins

Complex Assembly Structure: 384 Individually Controllable Reaction Vessels

The customer’s objective was to produce an assembly featuring 384 reaction vessels that can be individually pulsed and controlled via electrical current. The assembly consists of 24 separate strips, each containing 16 reaction vessels and 17 metal pins, all secured within a plastic frame. These strips are made of two materials—a transparent and an electrically conductive component—directly bonded to the metal pins. The final assembly is covered with a transparent lid and sealed in a thermoformed tray with Tyvek film for sterilization.

From Semi-Automation to an Integrated Manufacturing Cell

This project began around 2012 as a 2K tooling solution where pins were manually inserted into a fixture by two employees. In this original setup, the pins were overmolded with transparent plastic at the pre-molding station and then with black conductive plastic at the second station. A separate tool was used to mold the frame, followed by assembly, ultrasonic welding, and Tyvek-sealed blister packaging.

Due to the initially low production volumes, our strategy focused on a semi-automated process with manual intermediate steps. Ultimately, the project comprised three separate tools to cover the entire assembly process following the 2K molding.

However, as demand increased, manual pin insertion reached its economic limit. Two years ago, we developed a fully automated 2K tool that integrates all injection molding stages, automated pin feeding, and subsequent assembly steps into one fully integrated manufacturing cell.

Precision Engineering: Tooling and Injection Molding Synergy

In technical terms, this is effectively a three-component tool, as the high-precision placement of the metal pins serves as the “third component.” Aligning the pins with enough accuracy to ensure the plastic perfectly encapsulates them is a significant engineering challenge. Furthermore, the second plastic component requires a meticulously balanced interplay of material shrinkage, sealing, thermal management, and injection pressure. The molding process itself significantly influenced the tool design to ensure the final product met strict customer specifications for geometry, dimensional accuracy, surface finish, and electrical conductivity.

A Holistic View of the Process

Implementing multi-component molds requires technical finesse and a holistic perspective on the entire production line. During the injection of the second component, the stability of the first component and the precise feed of the metal pins must be maintained simultaneously. The more components involved, the more complex the process ramp-up becomes before the line reaches optimal performance.

Increased Efficiency and Optimized Application Quality

Individual part geometries and parameters must always be validated against the specifications of the final assembly. We found that parts which were individually within tolerance could still cause issues in the final product; for example, a slight deflection in the assembled plates—though within the specified tolerance—initially hindered the customer’s robotic pipetting process. We identified and corrected this through process adjustments.

By moving to a fully automated process, we improved individual cycle times and eliminated previous fluctuations. The automated manufacturing cell now allows for continuous production, interrupted only by scheduled maintenance. Ultimately, we reduced the cycle time by approximately 20% while significantly increasing part quality through automated precision.