The overall look of PlasticX
The top view showing the waiting container and eight bins.
The two entrance chutes used to receive plastic items.
The pair of rollers and conveyor belts used as the compression mechanism.
The claw used for sorting the plastic items.
What it does
Users can dispose of their plastic waste and the machine will do sort them according to its corresponding plastic type. It strives to solve the issue where plastic sorted ineffectively is unable to be recycled and returned to the system causing waste.
Over the past 50 years, global production and consumption of plastics have increased more than 20-fold, and plastic production has reached 320 million tonnes a year. Most consumers are unaware of the fine distinction among various types of plastics but gaily throw them into a single bin, not knowing that different types of plastics cannot be processed together for effective recycling and reuse, creating huge waste and plastic pollution. We decide to solve this issue of unthorough plastic sorting by proposing "PlasticX". Our inspiration comes from the "SamurAI" robot in recycling plants. Instead, we bring the recycling plant to the public.
How it works
The entrance chute contains a pair of rollers that compress any incoming plastic items. A force sensor is used to reactive the rollers once the applied force exceeds the threshold, allowing the item to fall without further compression and preventing damage to the machinery. A combination of NIR and visual spectrum optical sensors, a camera, and a weight sensor is used to collect data on input items. Principal component analysis is then applied to reduce the data dimension while emphasizing the variation between the different plastic types, simplifying the final classification step using support vector machines. This method has been shown to have up to 97.5% accuracy .  Shichao Zhu, Honghui Chen, Mengmeng Wang, Xuemei Guo, Yu Lei, GangJin, “Plastic solid waste identification system based on near infrared spectroscopy in combination with support vector machine”, Advanced Industrial and Engineering Polymer Research, vol. 2, no. 2, pp 77-81, April. 2019
Since the very first day of our invention, our team used TRIZ tools to find the problems of the existing solutions as well to solve various conflicts that we have met during our design process. The tools include 5 Whys, 40 inventive principles, 76 standard solutions and trimming. We started by discussing and drafting a schematic in our meeting by paper and pen, and drawing a rough outline of how the shape our product would be. At the beginning, we decided to create a cylindrical bin that has eight segments in it, where the scanning process of the bin is right at the top of it. After we completed the first prototype, we discovered that it has a big flaw, because it can only sort one item at once. Then, we come up with a new design that is inspired by a doll claw machine. It has a cuboid body and inside of it is segments of eight containers follow by another container placing on top of it to collect the recyclables. Also, we added a pair of rollers inside the chutes to compress the plastic items to save the space of our container. Thus, we arrived at our final product.
How it is different
Compared to an ordinary recyclable bin, our design is unique for its ability to accurately sort a relatively large volume of plastic waste into the 7 plastic types, contrary to most solutions currently on the market, as they are lacking due to the inability to take in more than one item at a time and being unable to thoroughly sort plastic to a sufficient purity and specificity. This is made possible using the simple but highly effective classification process described above. The use of a waiting container to store items to be sorted and an automatic claw to send items to its corresponding bin also allows our product to cope with larger input volumes, without having to wait for the last item to be sorted before receiving the next item. Lastly, our product contains a compression mechanism located at the entrance of the bin which solves the problem of a bulkier product due to the increased number of bins for different plastic types.
In the future where fluorescent ink technology for sorting plastics is made widespread, plasticX will install the new fluorescent light sensors to make use of the new technology so that our product can have higher efficiency, remain relevant and also be more flexible. The design and technology of PlasticX can be paired with different sensors and repurposed to help in the tedious sorting of other items. We will also work more closely with plastic producers and recyclers to be able to improve the effectiveness of our products in terms of sorting and meeting the needs of plastic recyclers to help close the loop of the plastic production system.