P18432: Plastic Bottle Rope Machine Improvements

Problem Definition

Table of Contents

Team Vision for Problem Definition Phase

During the Problem Definition phase our team aspired to identify all of the different desired characteristics of the finished product and quantify as many of those desired characteristics as possible.

Through the course of this process our group was able to define the desired requirements from the conversations with our customer and from these generate the Engineering Requirements for our project.

Project Summary

Plastic bottles are currently overly abundant in developing nations such as Haiti with no feasible path to recycling. A plastic bottle rope machine would be able to transform these waste bottles into usable and saleable rope while employing operators of the machines. Repurposing these bottles would reduce pollution in affected areas and improve quality of life by repurposing the plastic rather than disposing of it through the use of landfills or burning. Last year’s MSD team (2016-17) produced a prototype for both braided and twisted rope; the twisted rope machine was sent to Haiti for testing while the braided rope machine was not completely functional.

The goal of this MSD project is to create a new refined process for the preparation and processing of bottles into string and, in turn, rope. Specific goals of this project include increasing the maximum length of rope produced, preventing rope from unravelling with use, and streamline rope production procedures. The end product will be mainly comprised of easily sourced components, transported in a flat bed truck, operable by unskilled workers, and profitable in operation.

Use Cases

This project will be used in third world countries such as Haiti where there is an overabundance of recyclable plastic bottles but there is no clear path to recycle them. Such a situation creates a great business case for transforming these bottles into a usable and valuable material rather than becoming waste.

Figure 1: Typical Use Case Flowchart

Figure 1: Typical Use Case Flowchart

Figure 2: Typical Use Case Flowchart for Creating Rope

Figure 2: Typical Use Case Flowchart for Creating Rope

Figure 3: Typical Use Case Flowchart for Rope Applications

Figure 3: Typical Use Case Flowchart for Rope Applications

Project Goals and Key Deliverables

Our project aims to develop a complete system to take raw, recyclable, bottles and through a number of processes transform them into useful, usable rope while simultaneously employing people in the process. The distinct deliverables associated with this outcome are the artifacts that will be used to: prep the bottles (if necessary), cut the bottles into strings, transform the individual strings into rope either through braiding or twisting, and the process and documentation for the entire system including an financial analysis proving the case for economic viability.

Customer Requirements


Decompose the Problem Statement into functions of elements needed to satisfy the customer.


Customer Requirements were compiled from a combination of sources; the bulk of the customer requirements were found in the PRP with some clarifications needed during our customer interview with additional requirements being added as needed.
Figure 2: Customer Requirements

Figure 2: Customer Requirements

Inputs and Source

  1. PRP.
  2. Problem Statement.
  3. Customer Interviews.
  4. Template and Example.
  5. Guide & other stakeholders.

Outputs and Destination

  1. Engineering Requirements.
  2. House of Quality.

The full Customer Requirements document can be found as a page of the "Requirements and Testing" Excel document.

Engineering Requirements (Metrics & Specifications)


Create a contract between the engineer and the customer where indisputable satisfaction of the engineering requirements equates to customer satisfaction.
Figure 3: Engineering Requirements

Figure 3: Engineering Requirements

  1. References: https://edge.rit.edu/edge/PTemplate/public/Establish%20Engineering%20Requirements

Inputs and Source

  1. Customer Requirements
  2. Phase I benchmarking
  3. Standards, regulations, or other industry guidelines (e.g., ADA, EPA, OSHA, IEEE, ASME, etc.) The RIT library maintains an infoguide with links to standards databases.
  4. Selected concept list
  5. System Design
  6. Template and Example
  7. Guide & other stakeholders

Outputs and Destination

  1. Function Decomposition.
  2. Concept Generation & Development.
  3. House of Quality.
  4. System & Detail Design.
  5. Test Plans.
  6. Poster & Final Report.

The full Engineering Requirements document can be found as a page of the "Requirements and Testing" Excel document.


The designed system will be constrained in many metrics including weight, construction materials, and power source.

House of Quality


  1. Confirm that satisfaction of the Engineering Requirements implies that all of the Customer Requirements are met.
  2. Facilitate design trade off decisions
Figure 4: House of Quality

Figure 4: House of Quality

Inputs and Source

  1. Template and Example.
  2. Customer Requirements.
  3. Engineering Requirements.
  4. Benchmarking Data.

Outputs and Destination

  1. Provide input to the risk management process.

The full House of Quality excel document can be found here.

Design Review Materials

The full presentation document can be found here. "Problem Definition Review Presentation.pptx"

Plans for next phase

Team Plan

Individual 3 Week Plans

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