P18433: Nicaragua Bottle Upcycling Product Design and Manufacturing
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Detailed Design

Table of Contents

Team Vision for Detailed Design Phase

Phase 4 Team Vision

What is our plan?

What have we completed?

Progress Report

The team progress report to assess design aspect completion prior to the Detailed Design Review can be found here.

This progress report details what we plan to have accomplished by the Detailed Design Review, what has been accomplished so far, the tasks that remain to be completed, decisions we've made so far, and questions for our customer and guide.

Overall Design

Transfer Molding Design

Our current overall design consists of the 6 subsystems as defined below.
Overall Design Frame with Corner Braces

Overall Design Frame with Corner Braces

Design Revisions are where the previous design revisions of the system framing and component placement can be found.

Our reasoning for choosing specific parts for this design is summarized here.

Overall Design Frame with Corner Braces

Overall Design Frame with Corner Braces

Current Design System Architecture

Current Design System Architecture

Current Design System Architecture

Part Drawings

The full system assembly drawing package for the current transfer heating design can be found here.

Current Gutter & Mold Design

The gutter design was modified after new information was learned from initial prototyping. The gutter no longer uses a clipping mechanism and instead will be connected with the holes on the gutter flange. Additionally, the gutter is now tapered at one end to ensure proper mating between gutter sections. Further prototyping is required to adjust for proper dimensions.

New Gutter Design

New Gutter Design


The initial mold design is as seen below. For this design, a gate and runner system are still required as well as an ejection pin system to remove the part after molding. Documented research on how to design a mold can be found here.

New Gutter Mold

New Gutter Mold

Prototyping, Engineering Analysis, Simulation

Frame Strength

Top Frame with Corner Braces

Top Frame with Corner Braces

The most important aspect of the frame is to have the strength to withstand the expansion forces that the car jack will exert on the system. A secondary aspect is that the frame will be designed to support its own weight. The frame will be constructed out of strong 5.08 x 5.08 cm steel square tubing with a wall thickness of 0.3175 cm (2" x 2" x 1/8" nominal sq. tubing), unless stated otherwise.

The key structural elements to analyze in the frame are:

The key assumptions made in the following calculations are:

Impact of Moment of Inertial on Bending

Hollow tubing with larger moments of inertia were initially considered when designing the frame. Large moments of inertial are the result of larger cross sectional areas, larger cross section heights along the bending axis, or both. A thick walled tube that is oriented vertically has the greatest potential to resist bending.

These pieces of tubing include the following and are compared here.

The calculations for frame strength can be found here. These calculations do not reflect the diagonal corner braces that are seen in the pictures. From the calculations, it can be seen that using these cross sections yields beam deflections on the top tubing supporting the car jack of 9.1 cm, 5.5cm, and 0.9cm, from smallest cross section to largest respectively.

Equipment Weight

The legs and wheels on the frame will need to support all the design components. The total weight from all the components is found to be 263 lbs, not accounting for electronics, plastic input, and misc. fasteners.

All the system components and their weights are noted here.

Frame Strength Conclusions

Other methods to reduce the beam deflection in the frame are to provide more support for the horizontal tubing members by using framing on the corners. Using a 13.5cm (5.3 in) piece of tubing with the ends cut at 45 degree angles and attached as seen in the Top Frame CAD Model, the length of tubing susceptible to bending is greatly reduced. Finally, using the same square tubing throughout the design makes purchasing and sourcing the material much easier as long bulk sections can be ordered cheaper per unit length.

Frame Prototyping

To get a sense of the scale and clearance spaces within the frame, a rectangular prism was constructed out of slightly smaller 3.81cm x 3.81cm (1.5"x1.5") wood pieces. This frame prototype is seen below.
Wood Frame Prototype

Wood Frame Prototype

Plastic Melting Testing

Preliminary plastic melting tests were done on a hot plate to represent the conductive heating from the resistors along with an 1/8th inch piece of aluminum to represent the walls of the heating chamber.

Melting Testing: Setup

Melting Testing: Setup

The hot plate was initially set to 275 degrees Celsius as this is the melting point of PET plastic and the lowest maximum temperature of the system. Plastic PET chips were added once the aluminum had heated up.

Melting Testing: Plastic Applied

Melting Testing: Plastic Applied

Based on visual observation, the plastic in contact with the surface of the aluminum melted very quickly (about 2 minutes), however the plastic that was not in direct contact took longer to melt (about 8 minutes). This could be due to the fact that the melted plastic did not conduct heat very well and therefore the plastic on top was not getting hot enough. It appears as if the melting plastic was insulting the rest of the plastic chips.

Melting Testing: Plastic Melted

Melting Testing: Plastic Melted

The melted plastic is clear and has similar viscous qualities to hot glue. It solidified quickly and was fairly strong after cooling.

An aluminum block with a cavity was introduced to analyze the behavior of small container of plastic. This simulated the conditions within the heating chamber as there will be only one source of heat.

Melting Testing: Aluminum Chamber

Melting Testing: Aluminum Chamber

This test showed that the plastic immediately in contact with the heated surface melted, but the plastic past this point was unaffected. The aluminum block did not conduct enough heat up the sides to melt the entire cavity worth of plastic.

The top of the chamber was heated with a heat gun to see if some radiation heating within the chamber would help increase the melting rate of the plastic. However this only melted the very top layer which in turn insulated the plastic in the middle.

Melting Testing: Results from Aluminum Chamber

Melting Testing: Results from Aluminum Chamber

Based on these findings, the final design needs to be rethought and updated to accommodate for the possibility of poor melting conditions within the melting chamber.

Proposed Compression Molding Design

This design tries to accommodate the issues faced when performing the plastic melting testing. By decreasing the thickness of the desired output product and adding heating elements to both sides, there is a greater likelihood of even heat distribution through the thickness.
Proposed Design System Architecture

Proposed Design System Architecture

Proposed Design CAD Model

Proposed Design CAD Model

The new design is similar to original but with a new heating system. The structure has minor changes to accommodate the new melting chamber.

Proposed Design System Architecture

Proposed Design System Architecture

Schematics, Flow Charts, Simulations

Wiring Diagram & Programming Flowchart

Wiring Diagram

Wiring Diagram

All electrical components were approved by Professor Slack from the Electrical Engineering Program.


Programming Flowchart

Programming Flowchart

Bill of Material (BOM)

Purpose

In this BOM we evaluate currently hypothesized, studied and planned material costs. There are close to no services that we need employ thus we are using this as a budgeting platform. Overall we are certain that our current provided budget of $500 will be insufficient as estimated cost is already sitting at $850. We will be putting in a request for an increase that will allow us to purchase our materials and advance the project.

Services

Currently the only service we will be purchasing is the delivery fee from Klein steel when we place our raw material order for them to deliver the purchase to us. The cost of this service is $25.

BOM

Current BOM

Current BOM

Test Plans

Our test plan for experimentally verifying the engineering requirements are broken up into the following categories:

Test Plan Chart

Test Plan Chart

The working Test Plans can be found here.

These Test Plans were formulated from the Engineering Requirements, which can be found here.

The Test Procedures to describe the testing processes can be found here.

Risk Assessment

Risk Assessment Screenshot

Risk Assessment Screenshot

A working Risk Assessment file can be found here.


Through the processes of re-scoping the project, the importance of many risks have been lowered or completely eliminated. These risks include:

Additional risks have been mitigated by placing the plastic chips directly in the steel mold. These risks include:

An additional risk was added due to the results from the preliminary plastic testing.

Risk Chart

Risk Chart

Design Review Materials

Plans for next phase

Phase 5 Team Plan

Lessons learned from original design and MSD I


Immediate development structure into the pivot system for MSD II:


What we hope to achieve in MSD II:

After undergoing our design phase in MSD I we have learned a great deal about the physical, economical and geographical requirements of our system. After our testing phase proved that the hypothesized plastic behavior actually does not work as expected we have shifted project scope. Our main goal for MSD II is to create a sheet of laminate PET plastic that will have the capabilities of undergoing vacuum forming. This will be useful as the plastic will have the ability to gain an assortment of shapes with low constraint levels allowing for massively increased flexibility of the system. We will be producing a raw material fit for production of different products.

In the case that we finalize this earlier than anticipated we will move into product design for the vacuum former, but this is not in the current project scope.


Individual Three-Week Plans


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