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Customer Handoff & Final Project Documentation

Table of Contents 1 Team Vision for Final Demo and Handoff 2 Test Results Summary 2.1 Performance 3 Project Management 3.1 Schedule Management 3.2 Risk Assessment 3.3 Budget Management 4 Final Project Documentation 4.1 Presentation Documents 4.2 Technical Documents 5 Recommendations for Future Work 5.1 Future Work 5.2 PRP Updates 6 Plans for Wrap-up

Team Vision for Final Demo and Handoff

Despite the situation resulting from COVID-19, the fourth and final phase of MSDII was productive and successful. In speculation of the school closing, team concRIT made a quick effort to remove the printer and all project materials from the campus. With the project safely offsite, machine testing continued in inventive forms that allowed one team member to safely continue conducting tests about 2-dimensional performance. Additionally, work continued on documentation (EDGE, Technical Paper, Poster, and video). This page reflects the culmination of effort from team concRIT on P20652.

Test Results Summary

Without a doubt, the biggest impact from COVID-19 for our team was testing. The majority of testing came to a halt after the machine moved off campus, in-person team meetings were limited. The test results for marker drawing and light painting are described in the Test Results section of the Integrated System Build and Test page. Since the Z-axis was not completed, there is no test documentation to present.

Performance

The table below captures which engineering requirements the printer was able to meet. Those in green are fully tested and met, yellow may not have been completely test or were out of range, and red were not able to be met within the scope of this project.

• Process times were not formally measured, although approximate times from team experience and testing can inform the expected range. Material testing for setting time intended to factor into both ER2 and 3, while experience from the material development for ER5 indicates that this requirement would have been passed. ER1 and 4 were untested due to prototyping being cut short.
• We failed to test the extrusion system to the point where we could adequately measure the extrusion flow rate, and therefore determine an estimation for print time based on volume. However, idealized predictions of flow through the extruder were performed, which can be modified and improved with additional mixture and extruder testing to address ER2.
• Due to time constraints, we failed to develop the mixture to the point where we can effectively test the concrete for compression and tension strengths for ER11 and 12. Due to our mortar selection and extruder assembly design, the MSA does not meet ER8. Without testing extrusion in 2 or more axes to print test parts, ER7 and 9 cannot be verified. However, testing in 2 dimensions showed ER6 was met.
• ER13, 14, 19, 20, and 23 were all met by design.
• All machine size requirements, except ER15 were met, where ER15 was marginally met.
• Cost requirements ER21 and 22 were met.
• Ergonomics requirements, ER24, 25, 26 and 27, were not considered due to shortened prototyping.
• Auger prototypes were printed with updates being made between each version. The first prototype was constructed to fit the WYE shaped PVC extruder housing snugly. The first prototype was not able to smoothly extrude concrete because there was too much friction between the auger and the PVC extruder housing. In later iterations, the radius of the auger was decreased to allow for more space between the auger and the PVC extruder housing. Taking an extra look into engineering tolerances, could have avoided this issue.
• In motor selection, we failed to adequately produce a model that could account for the complexities involved with using a motor coupled to a gearbox. Although a gearbox provides the advantage of torque/speed output manipulation, without a predictive model we resorted to physical testing of a geared stepper motor. This is not a thorough or efficient method to assess the validity of motor selection. It is recommended that a future team develops a method to theoretically assess the performance of a geared stepper motor so as to not exclude them as a potential solution.
• Shortcomings in developing the auger geometry and mixture parameters resulted in the inability to create an accurate Cura profile.

Project Management

Schedule Management

An effect of the pandemic related shutdowns we faced was the inability to continue purchasing components for our project. The agile build and testing schedule we followed resulted in this meaning that some of the components for the Z-axis would not arrive to the team. The impact to the project is reflected in our Schedule Management Plan For the final document, see this link.

Risk Assessment

Since the state of the project did not change since the previous stage, the risk and problem tracking were finalized on the last page. For the final Risk Management and Progress document, see this link.

Budget Management

Carefully tracking the budget throughout the second semester of the project horizon yielded some interesting results.

• The total accumulated cost for all components and including shipping was $1,318.04 (69.37% of the allocated budget).
  • Total shipping costs was $122.02
  • Over 750 individual components including hardware
• The greatest spending took place for the Y axis build and integration.
• Components belonging to the Motion category had the highest cost.
• Donations and a budget increase served as positive cash flows, helping to reduce costs.

Breakdown by Phase

Breakdown by Category

Budget Cash Flows

For the final Budget Management document, see this link.

Final Project Documentation

All presentation and technical finalized documents can be found here.

Presentation Documents

• Technical Paper: The technical paper describing our design and results in pdf format.
• Poster: The poster overviewing the project (that would have been presented at Imagine RIT) in pdf format.
• Lightning Talk Video posted on YouTube.

Technical Documents

• Performance vs Requirements
• Bill of Materials
• Updated Project Readiness Package for P20652
• 3D_printer_Ct_v8.zip: CAD folder including Solidworks assembly and all part files. The download is a 141.9MB zip.
• Machine Assembly/Disassembly Instructions
• Machine Build Instructions
• Electrical Assembly/Disassembly Instructions
• Software
  • Cura Setup Cura printer setup document.
  • The printer can be connected to from own wifi signal. First find the SSID, P20652, on your device. The password is MSDP20652. At this point you should be connected. To view the printer interface, find the IP address of the device and enter IP:8080 into any web browser. Alternatively, you can enter duettest.com to connect.
  • Duet3D Wiki Link to the Duet 2 Wifi wiki.

Recommendations for Future Work

Our experience from the design and prototype has granted us a unique perspective on the current state of the project and project continuation, as well as the ability to provide advice to future teams working on this concrete printer. The most important lessons from both our progress and shortcomings can be adequately summarized here.

Future Work

While we did our best to ensure a completed product for the customer, here are some improvements and activities for future teams to consider.

• Z-Axis:
  • Some Z-axis components have already been purchased and delivered.
  • There are still Z-Axis components that need to be purchased.
  • The Z-axis must be built and integrated with the existing structure.
• Mixture development:
  • The basic mortar-based mixture that we used for this iteration of the project will only be adequate for so long.
  • Additional mixture components such as fly-ash, clay, fibers, etc.
  • Tensile and compressive strength testing should be performed.
• Mixture Reservoir
  • The current design requires continuous feeding of concrete into the extruder.
  • There should be a system that holds a large amount of mixture and feeds to the extruder.
• Nozzle Bead-shaping Attachments:
  • Many industry printers have a way to smooth or reshape the bead. This video gives some good ideas.
• Extruder Self-flushing Procedure:
  • The current design requires that the extruder be disassembled and cleaned after every session, or before the concrete has began to harden from inactivity.
  • There could be a system that automatically flushes the extruder into a waste container after such an amount of time.
• Testing Practices:
  • Testing practices should be improved so that process performance can be measured and analyzed.

PRP Updates

We have identified potential improvements that could be incorporated into the Project Readiness Package.

• The project would greatly benefit from having a civil or chemical engineer on the team. Someone with above-average knowledge of concrete should be dedicated to the research and prototype a concrete mixture specifically designed to work with our extrusion system.
  • OR a guide that has experience directly related to mixture development.
  • OR a situation where a class or individual partners with the team towards mixture development.
• We recommend to have at least one or two teammates possessing a graphics card ( preferably at least GTX 1080 performance) and RAM (16 GB+) supply that can meet the demands of a large, complex, existing solid models.
• This project is very mechanical and did not require a very high amount of electrical or computer engineering. There were over 750 individual components purchased for our project, including every piece of hardware.
• Either the mixture or the extrusion system could form the motivation for a separate project focused specifically on the design of those components and their integration to our printer.
  • The focus of the original project remains on improving the structure and integrating the extrusion system.
  • The additional project allows the two projects to be independently focused on overlapping goals.

Plans for Wrap-up

As the project has been off-site for this phase, a customer handoff is being scheduled so that they receive all of the project materials.

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