Product Development

Our product development team is working to connect outreach and engineering by designing items that we can create using our machines. More specifically, products are made during the injection molding process by melting the plastic pellets (created by the shredder) and injecting them into molds. We are hoping to create products that can then benefit the community, going along with our mission to put plastic recycling back into the hands of people. Currently, we are working with both the Ithaca Community Gardens and Ithaca Schools to create items to assist them in gardening and teaching, respectively.

The board of the Ithaca Community Gardens is excited at the prospect of a partnership with ARC because of  their interest in community engagement and need for new tools. We met with them at the beginning of the Spring semester and proposed simple products based on information from Dilmun hill, Cornell’s campus farm. We left the meeting with two product focuses: small clips to hold up tomato plants and plant markers for seed starting and rows. We considered more creative ideas, such as shaping the plant markers like the plant they are labeling, or embossing the name of the plant in the mold instead of writing on it, among others. After more discussion, we decided it would be more feasible to use one design that can be written on. While brainstorming ideas, our team came up with some great designs including leaves, trees, flowers, and more! The plan is to 3D print prototypes and take them to our next meeting with the Community Gardens Board to get feedback.

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With the Ithaca School District, we have been working with teachers from the science department to design models that could be useful in their curriculum. Currently designs are in the works for DNA and phase change models. These models are meant to provide high school students with an interactive learning tool that can help them visualize processes that happen on a molecular level. We are currently using software to design the models so that we can 3D print and figure out which is the best in terms of the needs of the teachers and students and in terms of feasibility and durability.

Kristen Ajmo
The Injection Molder

By Matthew Bell

The injection molder is the first machine to be made by ARC that will create a finished product. Plastic pellets are fed into the hopper, which leads into the melting chamber. The melting chamber is brought to the appropriate melting temperature of the plastic that is being used. After the plastic has been melted, it is then pressed down the melting chamber using a lever and piston. The plastic exits the melting chamber into the desired mold, which is in the shape of the finished product. After the plastic cools and solidifies, the mold is removed, leaving the finished product.

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There are many different ways to reform plastic into new products, but we chose to make an injection molder as our first recycling machine for a number of reasons. First, it seemed to be the cheapest option, with Precious Plastics estimating it cost them around $185. Also, we discovered we could make the machine without the need for intense machining or welding, therefore satisfying our goal of accessibility and ease of manufacture. This way, others can easily follow our initiative and expand the impact of this mission. Secondly, the injection molder offers a lot of creativity when it comes to products it can make. The parts are virtually only restricted by the mold design. In addition, once a mold is made, many replicas of the same part can be made quickly and easily, with just the pull of a lever. This would allow us to jump-start our operation, offering a very short lead time and large available quantity to our stakeholders right out of the gate.

Our design (represented in the CAD model below) takes inspiration from the Precious Plastics design, online research, and advice from Cornell professors. The main structure is built from 80/20Ⓡ, easily-assembled aluminum railed akin to an Erector SetⓇ. The lever and mounting pieces are made from aluminum bars, and the only necessary machining is drilling a few holes. The melting chamber is made from standard ¾ NPT tubing, allowing it to interface with standard nozzles, so the plastic won’t leak out. An adapter and nozzle attach to the end of the tube, which feeds the melted plastic into the mold. An aluminum cylinder is used for the piston to push the plastic through the melting chamber. The plastic is heated using band heaters that wrap around the tube and are controlled to the correct temperature by a temperature controller (not shown in the CAD model, shown separately). It is important to get the correct temperature, as going too high can create hazardous fumes. In all, the system easily fits on a desk and stands at about 3 feet tall.

 Injection Molder CAD

Injection Molder CAD

 Band Heater

Band Heater

A little bit more research and more testing need to be done to ensure that this design will work. However, we are very hopeful because similar designs have been successful in the past. After the completion of the injection molder, the next step is to make the molds for the products that we will be creating.

Kristen Ajmo
The Shredder

By Matt Bell

The first machine in our recycling process is the “shredder”. The purpose of this machine is to break down the collected plastic into small pellets. This serves three main functions. First, it makes the plastic of unknown number easier to separate. As each type of plastic has different properties (including density, melting temperature, etc.), a number of tests can be used to differentiate between them once the plastic is broken down. For example, if placed in a liquid of density 1.05 g/cm3, polypropylene (PP) will float, but ABS plastic will sink, allowing you to distinguish between the two. Secondly, the shredder makes the plastic easier to wash and store. Instead of having hundreds of plastic bottles lying around, we can have neat containers of plastic pellets, separated by type (or also by other things like color). Finally, the shredder allows the plastic we collect to be used in the injection molder, our second machine. These small pellets will be fed into a tube, which is then heated up. Once the plastic has melted, it is then pressed by a piston into a mold, where it solidifies and becomes the final product. The small pellets are easy to feed into the machine and have more surface area, allowing the plastic to melt more quickly in the melting chamber.

The design of our shredder closely follows that of Precious Plastics, a large inspiration for ARC as a whole. While eventually we want to completely design our own machines, we felt it more important to get fully-function machine right now, so we can get the ball rolling on the rest of the process. In simplest terms, the shredder has to break larger plastic parts into smaller ones. In order to accomplish that goal, this solution has a hopper to feed plastic parts into the box, where metal blades turn and press the plastic against a piece of perforated steel (sheet metal with small, uniform holes). Plastic is squeezed through the holes, creating equally-sized pellets, that fall out the bottom of the shredder into a collection bin. Most of the parts for this machine could be made with sheet metal, which was then manufactured using a waterjet cutter in the Clark Hall machine shop on Cornell’s campus. A sample of the resulting parts are seen below:

 Images 1 and 2: Sampling of parts for the shredder box

Images 1 and 2: Sampling of parts for the shredder box

The box itself was then welded together:

 Image 3: Mel welding the box together

Image 3: Mel welding the box together

 Image 4: Finished after welding

Image 4: Finished after welding

The only additional parts were the custom driveshaft which holds the blades, perforated sheet metal (purchased), and a hand-crank (purchased) to turn the driveshaft. The blades were attached to the driveshaft and the driveshaft was placed in the box, through the bearings. Then, the hand crank was attached to the shredder.

 Image 5: Matt Bell attaching hand crank to shredder

Image 5: Matt Bell attaching hand crank to shredder

The next immediate steps are assembling the blade guards, attaching the perforated sheet metal, adding a simple hopper, and making sure we can provide enough torque with the hand-crank to shred the plastic. In the long-term, we plan to revisit the shredder, making it more affordable and easy to make, without specialized equipment (i.e. remove welding steps), so that people without those resources can make a shredder, too. In the end, the shredder cost only about $200 and we think we can make that even lower!

             

We plan to have the shredder completed by the end of October and hope to make even more improvements by the end of the semester! We’re looking forward to having our first machine built and starting our personal recycling process.

Kristen Ajmo
Video Game Design

By Anthony Montoya

Warning: Melodrama.

During the early wintertide of 2018, our dear and glorious Outreach leader alighted upon the idea of creating a video game to promote ARC and educate the community about (alternatively) recycling plastic. Thus, he acquired RPGmaker and assembled the Outreach team, and hence a new world was born, and it was good.

Well, pretty good for a world that only consists of four unique character designs, dozens of lines of NPC dialogue, and one semi-polished demo. (There are four Outreach members. I think we’ve made decent progress over one semester.)

And so let us open a window to this world, the world of our video game, the world of ArcPG:\

Long ago, the whole planet was green and thriving. Humans lived separate from nature, in tall structures that stretched towards the blue and unclouded heavens. They created beautiful and terrifying machines of stone and oil, and they used them to conquer and lay waste to the earth. But everything changed when the planet counterattacked.

First, the weather assaulted humanity. Settlements were flooded; deserts were scorched. Snow storms swept towns into tundras. Hurricanes devastated entire regions. Lightning desiccated the soil. Ice melted, and oceans consumed most of the land, leaving only plundered archipelagos as the last bastions of humanity.

Most of human knowledge was lost to the sea. Civilizations degraded. Fresh water grew scarce. Many species of animals disappeared, replaced by horrifying creatures and monstrous amalgamations who attacked on sight. Disease and fever plagued the remaining humans. Millions died, and the rest could only pray for a savior or wait for imminent death.

After several (dozen) years, the surviving humans were few and far in between, living on islands lucky enough not to be devastated by storms. The survivors were more resistant to disease, more sturdily bodied, and more capable of surviving the extreme weather and vicious creatures of their angry planet. Their shores were plagued by monsters, and their technology was rudimentary compared to the past, but they lived with just enough.

Strange, mutated, but still benign plants began to sprout. Green hesitantly spread over the land again, and humans relied heavily on these natural resources to survive. Then, remnants of the old world began washing up onto beaches; damaged books, papers in bottles, even some old building materials and machines. The method of synthesizing plastic was rediscovered, and it quickly became a convenience that the surviving humans indulged in. Soon, a new renaissance began, as plastic goods improved the quality of life for many. Humans began to build towards the sky again, and their waste began, again, to accumulate in the sea…

Some people say that the Earth struck humanity down because humans were arrogant enough to aspire to reach the heavens. Some say that humanity is a pest that should be eradicated from the planet. Some say that humans were simply unlucky in having to weather a period of the earth’s tumult but that technology will be the miracle that preserves humanity. Some are still waiting for a savior to appear and bring back the good green Earth of old.

And some people don’t want to wait anymore.

ArcPG: The Lost Machines



Kristen Ajmo