Subsystem Build & Test
Table of Contents
Team Vision for Subsystem Level Build & Test PhaseOne of our targets for this phase was to make the heart of our project work: the heater. First of all, we built the frame by assembling all the purchased aluminium sections. We also placed the heater on top of the frame to verify that everything was fitting as planned. About the heater electrical connections, we had to include a switch and made all the necessary wiring connections to plug the heater to the electrical grid. After all these previous steps, we finally managed to run our heater and it worked better than desired. Another important step through this phase was the vacuum test which performance was very positive.
Test Results Summary
Summarize test results and assess effectiveness of test plans to unambiguously demonstrate satisfaction of the engineering requirements
- Quantitatively summarize the capabilities, performance, throughput, and robustness of your subsystems as demonstrated by execution of the text plan. Document your testing with photos or videos in addition to test data.
- Evaluate how well the test plan was able to confirm satisfaction of subsystem requirements
- Include snapshot of testing completed to date, and include link to live requirements and testing document
Inputs & Source
- Test Plan
- Subsystem fabrication
Outputs & Destination
- Test Results
- System integration
Before we purchased the materials for the frame we discovered some free 80/20 sections in the MSD storage in the basement. Our original design used 10 series (1.0”) 80/20 sections but all the material that we found was 15 series (1.5”). We modified the design to use these new larger pieces for the vertical sections of the frame as it would also increase the rigidity of our frame. After the frame was redesigned a new bill of materials was created for just the frame and the parts were then ordered. After the materials were acquired they were cut to size and loosely assembled to make sure everything fit correctly.
For the electrical connections, we had to connect the wires coming from the heater to the electric grid. We had two different wiring standards, the American one (Black, White and Green) and the European one (Brown, Blue and Green). As the plug is polarized, we had to pay attention to properly connect the black wire with the brown one, the blue with the white and the ground ones together. We made those wiring connections through several wire nuts.
Propane and Vacuum
Plastic Holder-Linear Motion System
In order to test the linear motion mechanism, 3D printed “glider” plates were made to ensure smooth motion before devoting the time to machine the plates. The wheels were initially assembled with washers to hold the wheel in the correct location. This caused the plastic holder to slightly bind while moving it up and down. Some washers were removed to allow the wheels to slightly pivot on their mounting bolt which led to less binding. A new design for the gliders was created so that the M5 bolts that hold the wheels could thread onto the plate. This design allowed for a more constrained path for the wheels and needs slight alignment before it will operate smoothly.
- Propane Figure 1: The vacuum Former's propane setup.
- The first piece in the green circle is the POL fitting for the propane tank.
- This is connected to an adapter which is connected to another adapter to connect to the shut-off valve.
- All of the threads except for the POL fitting's threads were wrapped in Teflon tape 4 times.
- The piece in the blue circle is a ball valve.
- The valve is an Apollo Model No. 8010301.
- Max pressure is 250 psi for propane.
- Inlet and Outlet diameter is 1/2"
- Previous designs had the shut off valve placed closer to the operator but because the liquid propane is the most volatile part of the system it is safer to have it close to the propane tank.
- The valve takes a quarter turn to close which is faster than the valve the propane tank comes with (3-4 turns).
- This change was recommended by Mike Nobes (our gas contact from Faro Industries) and a propane parts salesman at Jackson Welding and Gas Products.
- The valve is connected an adapter which connects to the regulator.
- The piece in the red circle is the propane regulator.
- The regulator is a Mr. Heater Horizontal Vent Two-Stage Propane Regulator. Item No. F273868.
- Max inlet pressure is 250 psi
- Outlet pressure is 11"-14" WC
- Inlet diameter is 1/4"
- Outlet diameter is 3/8"
- This regulator is meant for outdoor use because of its vent but after emailing customer support they said if we have ventilation that can use it indoors.
- Regulator is connected to a propane hose which connects to the heater.
Test ResultsBelow are links to videos of our tests
- The electrical part of the gas manifold was not turned on so propane was not being injected into the heater.
- Bubbles were also forming at the connection points indicating we were leaking gas.
- We added more Teflon tape the threads and the problem was solved.
- When the heater was initially turned on there was a lot of "dancing flames."
- "Dancing flames" disappeared over time until the heater was just a red glow.
- If "dancing flames" persist we will investigate if they are a problem.
- HIPS plastic was placed on the plastic holder and clamped on one side and moved toward the heater.
- The plastic started at 73oF and after a minute was at 208oF.
- The plastic needs to be around 350oF before it is formed. The heater will be able to meet that requirement and do it quickly
- Different angle of the same plastic test
In order to avoid crimping the propane hose, 90o elbows will be used to keep the hose out of the way (Figure 3). Figure 2 shows how the hose sticks out from the heater.
Propane Figure 2: Propane hose sticking out of manifold
Propane Figure 3: New Propane System schematic
Risk and Problem Tracking
Three risks were identified during this stage shown in the table above. The full Risk Management document can be found under the Risk Management page.
Functional Demo MaterialsInclude links to:
- Presentation and/or handouts
- Notes from review
- Action Items
Plans for next phaseindividual 3-week plan template for this)