P18676: Upcycling of 3D Printing Waste
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Detailed Design

Table of Contents

Team Vision for Detailed Design Phase

The team used the Detailed Design Phase to refine the plan and design proposed in our Preliminary Detailed Design Review. The work and data obtained during these weeks helped the team establish priorities, which will give us a clear direction to follow during the coming phase of MSD II. The main goals to accomplish during this Detailed Design Phase were the following:

Progress Report

What does the team plan to accomplish by the Detailed Design Review? The team has set out to work in four main components of the project prior to the Detailed Design Review Testing Testing involving the heating components CAD Modelling A complete CAD model detailing the different subsystems working congruently Technical Requirements Research More research regarding technical aspects of the heating elements and their interactions with the lead screw and barrel is required. Some values we would like to determine are:

Procurement The team will start investigating what items we want to start acquiring in order to move forward in the project. Key items to consider are the stepper motors, microcontrollers and their relevant drivers.

What tasks have been accomplished so far? A preliminary model of the subsystem comprised of a stepper motor, the lead screw and the barrel has been designed.

Programming Stepper: The Arduino library has been explored and we have successfully programmed both a stepper and servo motor. Continued research into Anaheim motor controllers is needed in the future.

Theoretical Study of Lead Screw: The lead screw has been modeled so that known parameters can be used to study flow rate based on stepper motor RPM. Continued troubleshooting and friction drag studies need to be done to complete model.

Die Design: Plastic extrusion and die design techniques have been explored. A rough prototype has been 3-D printed. Roller Wheel Testing: Wheels have been printed and the proof of concept test shows positive results. An updated design and styles of manufacturing the wheels need to be studied in the future.

CAD Model: Sizing hardware to mount the lead screw to the stepper is being explored. Bearings and flange mounts will be needed to mount the motor and barrel to the frame. While the parts do not need to be bought from McMaster, the CAD model uses the 3-D part files from McMaster for sizing purposes.

CAD Model Current Progress

CAD Model Current Progress

What tasks remain, and who is the owner of each? The table below shows the tasks that must be complete by the time of the Detailed Design Review. Each member of the team has been assigned a task for which they are responsible.

Responsibility Matrix

Responsibility Matrix

Notes: Testing of the heating components is scheduled to be completed by Tuesday, November 21. Tim has been working on this task and Adam will support him to make sure it’s complete on time.

What decisions have been made so far? Regarding our options for microcontrollers, the original idea was to explore the methods used to build homemade 3-D printing machines and translate it so that it meets our system’s requirements. However, it is possible that the firmware available (Repetier) will not be able to meet our requirements. The new plan is to explore the system used in coffee roasters. Once we have a good understanding of the methods they use in their heating systems, we will attempt to convert the equipment we have available at the Construct to replicate their methods.

What questions does the team have for the customer and/or guide in order to continue moving forward? Questions for Mike:

Engineering Analysis

Updated Requirements For testing purposes, it was decided that motor controllers would be simplified from the original into the following systems:

An upgrade to these features will be further developed once the system achieves basic functionality. The main focus for team is to get the system to extrude a consistent line of filament. Once this goal is achieved, higher level control systems will be implemented in the system.

Safety Requirements

The main safety requirements we must take into account are those highlighted by the Occupational Safety and Health Administration (OSHA). For our particular project, the main concern is the health hazards posed by the burning of ABS plastic. According to OSHA, “Materials made from and/or containing AN for which objective data is reasonably relied upon to demonstrate that the material is not capable of releasing AN in airborne concentrations in excess of 1 ppm as an eight (8)-hour time-weighted average, under the expected conditions of processing, use, and handling which will cause the greatest possible release.” In addition, we are required to minimize exposure to heating and pinch points as much as possible. This will be dealt with by the use of insulation and safety guards.

CAD Model

The main goal of the Detailed Design Phase was to develop a comprehensive CAD Model of our proposed design.

Proposed Design

Proposed Design

Section View

Section View

Frame Dimensions

The footprint of the frame will be 14 x 16 inches with a height of 40 inches. This will require us to cut the current frame we have to these dimensions.

Motor Assembly

The stepper motor will be attached to the lead screw using a belt and pulley system as seen on a previous design. The reason we are not using an "in-line" system is so that there is more room to access the lead screw, giving us several options for a hopper design.

Barrel Assembly

Die Design

Die Design

Die Design Features

Rollers

Roller Testing Rig Updated Design

Roller Testing Rig Updated Design

The early updates for the roller subassembly were completed in the Preliminary Detailed Design phase. These lead to simplifications and improvements that were then incorporated into the design.
Roller Final Design

Roller Final Design

Simplifications include the slider track and slider block. Improvements include thinned roller wheels, spring tensioned slider and slide lock. Further simplifications may be implemented in MSD II with input from the machine shop, when the design is closer to fabrication. (Note: The roller drive gears are not pictured.)
Roller On Frame Mount

Roller On Frame Mount

The rollers are mounted to the frame with a simple plate. The plate will be slotted to allow for x and y axis movement, and the 80/20 mount will allow for z axis movement. This will allow for variable settings for different plastics.

Bill of Material (BOM)

Once the CAD Model has been approved, the team will be able to build a Bill of Materials. Preliminary discussions of what we will need to build our machine have taken place. However, there are some technical items that are yet to be determined, such as the decision regarding our heating system. We will discuss as a team what our best options are for this, as well as other important technical requirements. Based on the feedback from the Detailed Design Review, we will select an option and then we will be on course to produce an accurate Bill of Materials.

Test Plans

Heat Test

Heat Test

Procedure We connected the heating cable to a Solid State Relay and ran a current through it to determine rise in temperature. Conclusions The main takeaways we got from this test are that this heating cable will not be sufficient for our project's needs. While the cable could most likely reach the temperatures that we require (which is about 400 degrees Celsius), it likely doesn't have enough thermal mass to keep the barrel and flowing material hot for continuous use. Going forward We will consider alternate heating solutions such as a cartridge heater or a band heater. These options have been tried and tested on benchmarked rigs. The next steps we need to take regarding our heating system are:

Completing these steps will enable the team to move forward in terms of developing the rest of the system.

Design and Flowcharts

This section should continue to be updated from your systems level design documentation.

Risk Assessment

Risk Management

Risk Management

Risk Analysis Matrix

Design Review Materials

Include links to:

Pre-Read

Slide Deck

Plans for next phase

Prior to the start of MSD II, the team has taken the time to analyze carefully several aspects of the project so far, regarding what we have done up to this point and what we will need to do moving forward.

What we've done

We sat down as a team and discussed were we stand at this particular point of the project and what we have done so far. Several items, such as team dynamics, team work ethic and the team's level of preparedness were discussed. The full results of this Team self-critique can be found in the document Self-critique

What we will do

individual 3-week plan


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