Maintaining Purity: Advances in Preventing Resin Contamination in 3D Printing

Contamination control is pivotal for consistent performance in vat polymerization 3D printing techniques such as stereolithography (SLA) and digital light processing (DLP). Even minute contaminants can negatively impact mechanical properties, dimensional accuracy and surface finish of printed parts. Engineers have developed key innovations across the resin workflow to avoid contamination.

1. Advances in Material Handling and Storage

New methods in resin storage and transport aim to minimize contamination exposure. These include:

Inert Environment Resin Storage

Storing and handling resins in positive pressure inert gas chambers prevents oxygen inhibition and absorption of environmental contaminants. Argon or nitrogen atmospheres maintain resin purity.

Automated Resin Transport

Resins are transferred between printers and storage tanks via closed tubing systems with peristaltic pumps. This avoids contamination while enabling precise fluid metering.

Disposable Resin Vats

Single-use resin vats guarantee each print batch has clean exposure surfaces, eliminating cross-contamination. Automated vat swapping streamlines this approach.

Vacuuming and Ultrasonic Resin Conditioning

Combining vacuuming to degas resins and ultrasonic agitation to suspend particles helps condition resins before printing. This process removes bubbles and improves consistency.

2. Contamination Detection and Removal

Advanced techniques also actively identify and eliminate contaminants already present through:

Laser Transmissivity Measurement

By measuring resin optical transmissivity, contamination screening identifies particulates and property changes from resin aging or chemical contamination. Sudden transmissivity reductions prompt resin replacement.

Centrifugation

Centrifugal separation efficiently extracts dense particulate contaminants suspended in resin samples prior to printing. The purified resin can then be recovered.

Micron Filtration

Final stage micron filters remove contaminants while transferring resin from storage to build vats, protecting print purity.

Targeted UV-C Exposure

Strategic germicidal UV irradiation clears biological microbe contaminants from resin between print runs without impacting resin reactivity.

3. Enhanced Print Processes

Finally, contamination can be avoided through robust printing methodologies:

Humidified Build Chambers

Controlled humidification of resin print chambers prevents moisture absorption and associated resin property changes over long prints.

Interlayer Resin Cleansing

Automated wiper blades clean printed part surfaces between layers, preventing accumulation of micro-debris that get trapped on upward facing surfaces.

Closed Loop Resin Recirculation

Continuous filtration and recirculation of resin around a closed build vat loop maintains purity even in large volume printing.

With rigorous contamination prevention and control measures across the entire resin workflow, 3D printing promises wider adoption for applications requiring exceptional material purity and consistency.