ATR-FTIR distinguished major 3D-printing polymer types in forensic samples

What the study found: ATR-FTIR spectroscopy with chemometric analysis was able to distinguish major 3D printing polymer categories in a set of 67 filament samples from the Australian market. The study also found that some filament subgroups could be separated when minor additives were present, and that raw filament outer coatings could differ chemically from inner cores or printed exemplars.
Why the authors say this matters: The authors say these findings matter for forensic interpretation of 3D-printed firearms and related components, because chemistry-based analysis may help develop interpretation frameworks and laboratory workflows where toolmark examination has limited effectiveness. They also note that the study addresses a gap in published research on 3D printing filament as forensic evidence in the Australian context.
What the researchers tested: The researchers examined 67 polymeric 3D printing filaments available on the Australian market. They used ATR-FTIR spectroscopy, which measures how a sample absorbs infrared light, together with chemometric analysis to assess variation among acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and polyethylene terephthalate glycol (PETG) filaments.
What worked and what didn't: The approach successfully identified filament from each polymer category. In some cases it also separated filament subgroups based on minor additives, but it could not identify specific suppliers. The study also reported spectral differences between outer surface coatings and inner cores or printed exemplars.
What to keep in mind: The abstract describes this as the first study of its kind in the Australian context, but it does not provide detailed limitations beyond the inability to identify specific suppliers. It also suggests that complementary techniques may be needed to improve specificity.

Key points

• The study analyzed 67 3D printing filaments from the Australian market.
• ATR-FTIR spectroscopy and chemometrics distinguished the main polymer types: ABS, PLA, and PETG.
• Some filament subgroups were separated when minor additives were present.
• Specific suppliers could not be identified from the ATR-FTIR results.
• The researchers found chemical differences between outer coatings and inner cores or printed exemplars.