InGaAs Sensor Selection for Foreign Matter Detection
Select standard InGaAs for cost-effective detection up to 1700 nm, or cooled extended InGaAs to capture 2200 nm polypropylene combination bands cleanly.
Polypropylene Twine Detection
Sorting Method
Identification of synthetic packaging materials within raw cotton prevents the contamination of high value yarn lots. This polypropylene twine detection relies on the unique spectral signature of the plastic compared to the natural cellulose of the lint. Fragments of twine often come from the bags or ties used during the harvesting and transport of cotton.
Because these fibers do not absorb standard cotton dyes, they appear as white or colored streaks in the finished fabric.
Spectral Identification
Near infrared sensors scan the raw fiber for the specific absorption peaks of the synthetic polymer. While white polypropylene is invisible to the human eye against white cotton, it is clearly visible to a swir camera. The polypropylene twine detection software analyzes the reflectance ratios to isolate the synthetic material.
This allows the system to trigger rejection mechanisms even at very high production speeds.
Contamination Risk
Small pieces of plastic can be shredded by the opening and cleaning machinery into thousands of tiny fibrils. Once dispersed, these fragments are nearly impossible to remove and will cause breakage during spinning or weaving. Early polypropylene twine detection at the blowroom stage is the most effective way to protect the quality of the entire batch.
Mill Cleanliness
Customers often demand certification that the fiber has passed through a dedicated cleaning line. Data from the polypropylene twine detection system provides a record of how many contaminants were removed per ton of fiber. This transparency helps mills justify the premium price of contamination free yarn.