It has always been challenging and demanding to sort a random mix of plastics during the recycling process. Many recycling companies resort to manual sorting which is labor intensive, time-consuming and costly. To tackle these problems, HKPC has developed the Opto-mechatronics Plastic Bottle Sorting System, which automates the sorting process of plastic bottles based on near infrared (NIR) reflectance spectroscopy. With different absorbance and reflectance spectra, the NIR sensor can identify particular plastic types. By measuring the wavelengths of peaks in the spectra, various plastics including polyethylene terephthalate (PET) and high density polyethylene (HDPE) can be recognized and sorted, providing an inexpensive and quick sorting alternative for the recycling industry.
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