P18433: Nicaragua Bottle Upcycling Product Design and Manufacturing
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Systems Design

Table of Contents

Team Vision for System-Level Design Phase

It was the goal of the team to decide on the overall design of the plastic melting and molding machine. To do this, the machine design must be broken down into sub-functions of the machine, and design components to satisfy the sub-functions individually. This is to be accomplished in the Functional Decomposition and Concept Selection sections. Benchmarking, a Morphological Table, and a Pugh Chart will be the tools used to compare the various proposed solutions. A visit to HARBEC Inc. (a local plastic molding plant in Rochester, NY) will help us to develop a solution to some or all of the sub-functions.

The team went through the process of Functional Decomposition and decided that the area that required the most design work was the heating and compression of the plastic. The visit to HARBEC was the primary inspiration for the solution to this problem and resulted in the current design that was selected. A System Architecture chart was created to further evaluate the selection.

Our notes from this meeting with Bob Bectold of HARBEC Inc. can be found here.

Functional Decomposition

The working Functional Decomposition can be found here and will be maintained by Vikas Patel.

Benchmarking

Benchmarking for compression methods

Benchmarking for compression methods

Benchmarking for plastic melting methods

Benchmarking for plastic melting methods

Benchmarking for different plastics

Benchmarking for different plastics

Benchmarking for resistance heaters

Benchmarking for resistance heaters

Feasibility: Economical, Market Analysis

Market Analysis

Market Analysis

Feasibility: Environmental, Water Quality Analysis

A link to the environmental feasibility research can be seen here.

All three studies looked at the effects of temperature and storage time on the material migration from the PET bottle to the water.

Results of each study indicated that during short sun-light exposure times, the PET-stored water quality barely changes. However, high temperature and CO2 presence increased the release of formaldehyde and acetaldehyde from the PET bottle to the water. A breakdown of each study is noted in the research document provided.

Feasibility: Prototyping, Analysis, Simulation

Screenshot of Melting Feasibility Spreadsheet

Screenshot of Melting Feasibility Spreadsheet

A link to the working melting feasibility spreadsheet can be seen here

Morphological Chart and Concept Selection

Morphological Chart

The working Morphological Chart can be found here.

Concept Development

Following the completion of the Pugh chart and concept selection, multiple possible concept solutions were generated. Short descriptions can be seen below and sketches of the concepts can be seen here.

Practical

This possible solution would be a melting and molding process that is the best fit to solve our problem statement.The design would include middle of the road elements to sufficiently accomplish the goal.

Economical

The economical solution would require less complex elements to be economically feasible for implementation in El Sauce, Nicaragua.

Ideal

The Ideal solution to our problem statement uses the top of the line elements as well as multiple elements for each sub function. Although this would be the most expensive solution, there would be the most safeguards for each sub function when in use.

Precious Plastics

This possible solution uses elements that are the most similar to the small scale plastic recycling machinery shown on preciousplastics.com

Complex Mold (Precious Plastics Design)

This Possible solution heats and melts the plastic chips inside the mold. The rest of the equipment setup is similar to the precious plastics example.

Concept Selection

Pugh Chart

Pugh chart

Pugh chart

Screening Matrix

Screening matrix

Screening matrix

A complete file of the Pugh charts can be found here.

Based on our Pugh Chart analysis, we determined that the Complex Mold solution is the most feasible. It has some of the best system controls and is a reasonable and practical solution to our problem that we will be able to produce.

Systems Architecture

Initial System Architecture, Next Iteration in Preliminary System Design

Initial System Architecture, Next Iteration in Preliminary System Design

System Inputs

The three inputs for our design include energy, plastic, and information. Energy input consists of power supplied from the grid which is 120 volts AC. The plastic input is the plastic chips that are meant to be upcycled. The information input consists of any human information interactions required to run the melting and molding process successfully.

The energy input's main use is in the heating process to melt the plastic. The plastic input is required to have a material input that is to be melted and molded. The information input serves the purposes of controlling the internal mold temperature through a manual dial and applying the compression force on the mold through a mechanical device.

Failure Modes

Some potential failures modes of this system could include:

Designs and Flowcharts

Current System Level Schematic

Current System Level Schematic

Risk Assessment

New risks

The new risks that have been discovered through the system design phase include:

A working Risk Assessment file can be found here.

Risk Mitigation

Three of our current risks have an importance of 9 and are detailed below.

Four of our current risks have an importance of 6 and are detailed below.

Design Review Materials

Plans for next phase

Personal 3 Week Plans


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