Detailed Design

Table of Contents

1 Team Vision for Detailed Design Phase
2 Prototyping, Engineering Analysis, Simulations
3 Drawings, Schematics, Flow Charts, Simulations
4 Bill of Material (BOM)
5 Test Plans
6 Risk Assessment
7 Design Review Materials
8 Plans for next phase

Team Vision for Detailed Design Phase

This phase was focused on detailed design for low risk items such as the structure.

What did your team plan to do during this phase?
- Decide upon structure type and linear motion solutions.
- Create a 3D model for the structure.
- Demonstrate working extruder prototype.
- Sent out more letters for sponsorship.

What did your team actually accomplish during this phase?
- We decided to move forward with an XYZ Cartesian. For linear guide rails we are looking to use carriage and rollers and for actuation, we are looking into ball/lead screws.
- A full 3D model of the structure and animation of the printer assembly has been completed with exception to fasteners.
- We were able to demonstrate successful extrusion with our latest extruder and auger prototypes.
- Sent out roughly 15 letters for sponsorship requisition.

Prototyping, Engineering Analysis, Simulations

During this phase additional prototyping, analysis and simulation were performed by each team.

Mechanical

Prototyping of the extruder was continued. A successful extrusion example is shown below.

Extruder prototype.

Extruder prototype testing.

Extruder prototype test GIF

This auger iteration had a smaller diameter allowing it to turn more freely. Additionally, the mixture used was a derivative of the Portland Cement Mortar Mix which worked fairly well.

Structural analysis

A static bending analysis for the x- and y-axes was completed to facilitate selection of aluminum extrusion profile. The maximum deflection was calculated for 6 different profiles from FramingTech. Three loads were considered: our estimate of the extruder weight, 2x this estimate, and 3x this estimate.

In the y-axis, the beam was assumed to have pin supports at each end and the extruder was applied as a static point load at every 10mm along an assumed 1.5m long beam.

In the x-axis, the beam was considered as a cantilever beam from a fixed support at the vertical beam toward the extremities. A worst-case analysis was performed by approximating the applied load as the sum of the entire extruder load (with factors of safety) as well as the weight of the y-axis beam.

From this analysis, we conclude that 45x45 profile will be used for the machine. A maximum deflection of 0.00085m was calculated in the y-axis under the extruder load with a factor of safety of 3. A maximum deflection of 0.00057m was calculated in the x-axis under the extruder load with a factor of safety of 3.

The matlab file used for the analysis is found here.

Electrical

A table displaying all of the variables and results in the system wide power analysis. The results yield that a 200W power supply should suffice for all functionalities, with a built in safety factor. For in-depth description see the "System Wide Power Analysis" document below.

Fig. 1: Power Consumption Calculation Table.

Fig. 2: Projected Total Power Consumption Graph.

Fig. 3: Power Supply Selection Choices/Benchmarking.

A few files are provided to show analysis for System Power, Power Consumption, and End-Stop Selection.

System Wide Power Analysis

Power Supply Consumption Calculation

Power Supply Proposal

End-Stop Selection Plan

Software

A Cura profile has been created for an example print of the RIT logo. The Cura settings are shown in the images below. The tool-path has been recorded and is shown in the video below.

Cura extruder settings.

Cura machine settings.

Cura profile settings.

Software Profile of Example Print.