Mold Inserts and Electroplating Processes (EP)

Dr. Markus Guttmann [Contact]

The activities of the group aims to offer, develop and optimize the combination of different (wet-chemical and galvanic) process steps to fabricate metallic microstructures in nickel or copper. Furthermore we manufacture nickel mold inserts for the use in polymer replication (i.e., hot embossing, thermoforming or injection molding).

The mold fabrication at IMT combines mostly a lithographic technique (X-ray lithography, UV Lithography, Ebeam-Lithography, Laser lithography), to generate a nano- or microstructured substrate, and a nickel electroforming process to obtain a negative galvanic copy of the original structure. Depending on the realized / desired nickel thickness “thin” shims (up to 500 µm) or “thick” tools (up to 5 mm) can be fabricated and used in the in-house replication laboratory. Link

In general, the mold fabrication at IMT includes the following process steps.

  • Supply of structured substrate (master piece)
  • Structure characterization using SEM and/or AFM
  • Metallization to generate a conductive plating base
  • Wet-chemical activation of plating base
  • Nickel electroforming
  • Substrate removal
  • Resist removal
  • Mechanical post-treatment to generate the outer dimensions
  • Structure characterization using SEM and/or AFM

Besides the application of lithographic methods and as an alternative technology for low-cost solutions we are able to use the combination of a joining process and nickel electroforming for mold fabrication. Hereby nano or microstructured master pieces made in glass or plastics (i.e., by Deep Proton Writing, Reactive Ion Etching, or 3D Printing) were fixed on a suitable substrate using an automated gluing process. The fabrication process for the final mold then is continued in a similar way (as mentioned above) with the coating of the conductive seed layer.

In addition to the mold manufacturing our group offers

  • the fabrication of thin nickel shadow masks to apply for structuring applications with PVD technologies,
  • the use of nickel electroplating to up-plate nano and microstructures and to fabricate thick mask plates,
  • the use of copper electroplating to fill microstructures or to apply copper electroforming on special metals (i.e., tungsten)
  • the testing of new anode materials or entire electrolyte systems
  • the development and use of wet-chemical etching processes for metallic layers.
  • the development and testing of analytical methods for galvanic processes

The existing plating lab equipment allows for the use of electrolyte volumes of up to 100 liters, substrate sizes of up to 300 x 300 mm and several consecutive wet-chemical process steps. In addition to a second chemistry lab, our working group also manages the institute's 3D printing lab, where several SLA and FDM printers are available.

All galvanic processes and process combinations for mold manufacturing are parts of our technology offer of the open access research infrastructure KNMFi and for bilateral enquiries from the industry. We always intend to upgrade the technologies according to current application needs and to convey the value of the technologies through various applications.

Our current cooperation partners are:

 

Training and Education: As part of the institute's interdisciplinary activities within the KIT, the three-year training program for chemistry laboratory technicians and DHBW students has been coordinated and carried out within the working group for many years. The trainees use the institute's infrastructure throughout their training, in particular the aforementioned second chemistry laboratory with a wide variety of up-to-date equipment. (link PEBA)