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3D measurements on extrusion marks in plastic bags
1Nationaal Instituut voor Criminalistiek en Criminologie, Brussels, Belgium. veerle.berx@just.fgov.be
Journal of Forensic Sciences
|October 2, 2002
Summary
Non-contact laser profilometry effectively detects manufacturing defects in garbage bags, including extrusion lines in low-density polyethylene. This technique offers a novel way to analyze surface irregularities and potentially link bag segments.
Area of Science:
- Materials Science
- Manufacturing Engineering
- Quality Control
Background:
- Garbage bag quality is crucial for containment and waste management.
- Traditional visual inspection can miss subtle surface defects.
- Understanding surface topography is key to identifying manufacturing flaws.
Purpose of the Study:
- To investigate the use of non-contact laser profilometry for analyzing garbage bag surfaces.
- To identify and characterize manufacturing defects like fish eyes, arrowheads, scratches, and extrusion lines.
- To compare laser profilometry data with visual inspection findings.
Main Methods:
- Scanning of various garbage bag surfaces using non-contact laser profilometry.
- Analysis of height profile data to detect surface anomalies.
- Correlation of detected features with known manufacturing defects.
Main Results:
- Manufacturing defects (fish eyes, arrowheads, scratches) were identifiable as height profile differences.
- Extrusion lines were detected in low-density polyethylene (LDPE) bags, with correlation lengths of centimeters.
- Extrusion lines in high-density polyethylene (HDPE) bags were on the order of 0.1 micrometers.
Conclusions:
- Laser profilometry is a viable method for objective detection of garbage bag surface defects.
- The technique can differentiate between defect types based on their topographical signatures.
- Extrusion line characteristics measured by profilometry may enable linking of sequential garbage bags.