Printing on a Substrate for PDMS Molding Applications

One common motivation for additive manufacturing is reducing time and cost for some tooling applications, such as master patterns for PDMS molding. When using additive manufacturing to shorten lead times, it is important to consider printing only what needs to be printed to avoid adding extra time to the process. Using microArch® printers, these two ideas converge, and lead times for certain 3D printed tooling applications can be even faster relative to other additive processes.

Printing on a Substrate

Printing on a substrate reduces build times, allowing the microArch system to focus on fabricating the much smaller features where high resolution and detail is critical. The most common substrate used to print on is glass, like a microscope slide. While a glass substrate may be a more ergonomic solution for handling small parts, the adhesion between the printed part and the glass is not strong enough for PDMS molding applications. The adhesion needs to be strong enough so that the features on the substrate can survive the demolding process. Adhering an optically clear vinyl sheet to the glass substrate first addresses this issue. This process is cost effective, and only takes minutes to prepare.

This sample microfluidic device master pattern for PDMS molding has a 4mm base and 400µm channels. It would take 4-5 hours to print the entire master pattern. A 3mm glass microscope slide and a 1mm Rinzyl disposable microscope slide were aligned and glued together removing the need to print the 4mm base. Adding the prefabricated base to the platform prior to printing, meant that only the microchannels needed to be printed, which takes only 30 minutes to print.

CAD Model of Sample Microfluidic Master Pattern for PDMS Molding
Sample microfluidic master pattern with printed base
Sample microfluidic master pattern with prefabricated base

Testing the Master Pattern

Adhesion of the printed features on the substrate was tested by placing packaging tape on the top surface and quickly peeling it off. After several cycles of removing the tape, there was no delamination from the substrate.

Testing the adhesion of the master microfluidic pattern printed on a substrate

About BMF

Boston Micro Fabrication (BMF) specializes in micro precision 3D printing. Our microArch system uses PμSL technology, a unique 3D printing approach that leverages light, customizable optics, a high-quality movement platform, and controlled processing mechanics to produce the industry’s most accurate and precise high-resolution 3D prints for product development, research, and industrial short-run production. The technology represents a true industry breakthrough by empowering product manufacturers to capitalize on the benefits of 3D printing without sacrificing quality or scale. Contact us to learn more about PµSL technology for micro 3D printing.