Table of Contents
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Team Vision for Subsystem Level Build & Test Phase
- Full Design Package
- Additive Instruction
- Machining Instruction
- Assembly Instruction
- Simulations Completed
- Vibration, valid through P16103
- Vibration, valid for eigenvalues
- Thermal, steady state
- Loading, launch
- Manufacturing Underway
- Prototypes built and tested for components
- Rails started
- Ultem started
- Prototype II
- Integrating test and engineering unit parts
- Practice for assembly
- Intended so we always have a working cubesat, and replacing parts along the way to increase our testing capability
- Start to convert to final engineering unit
- Tests
- Fit Test
- Tabletop Deployment Test
- Assembly Instructions
- Documentation Tests
- Initial Shake, Random Vibration, Random Shock Tests
Week 3 Individual Goals
Anthony, System Integrator
- Machining Tests (w2, 8 hours) On rail configuration and assembly practice
- Printing Tests (w3, 8 hours) Test shapes, and bottom plate
- Wire making practice (w3, 1 hour) Making small compressed coils
- Logistics (w4, 4 hours) Ordering, scheduling, documenting
- Fit and Assembly Testing (w4, 4 hours) Assembly and test the fit of components
- Design Review (w4, 3 hours) Reviewing Design for improvements, basic research testing
Paul, Deployable Mechanism Designer
- Machining Tests (w2, 4 hours) On rail configuration and assembly practice
- Printing Tests (w3, 8 hours) Test shapes, and bottom plate
- Design work (w2-3, 10 hours) Deployment Switches, Final Revisions,
- Simulation work (w3, 5 hours) Final Simulations for Vibration and Steady State Thermal Conditions
- Fit and Assembly Testing (w4, 4 hours) Assembly and test the fit of components
- Design Review (w4, 3 hours) Reviewing Design for improvements, basic research testing
Rob, Structures Designer
- Machining Tests (w2, 4 hours) On rail configuration and assembly practice
- Design work (w2-3, 10 hours) Deployment Switches, Final Revisions, Final Simulations for Vibration and Steady State Thermal Conditions
- Printing Tests (w3, 10 hours) Test shapes, and bottom plate
- Simulation work (w3, 5 hours) Final Simulations for Vibration and Steady State Thermal Conditions
- Fit and Assembly Testing (w4, 4 hours) Assembly and test the fit of components
- Design Review (w4, 3 hours) Reviewing Design for improvements, basic research testing
Tristan, Deployable Device Designer
- Printing Tests (w3, 8 hours) Test shapes, and bottom plate
- Creep Testing (w4, 4 hours) With Bottom Plate and Extreme Conditions
- Fit and Assembly Testing (w4, 4 hours) Assembly and test the fit of components
- Spring Tests (w4, 2 hours) See if the springs are correctly made and ideal for our work
- Design Review (w4, 3 hours) Reviewing Design for improvements, basic research testing
Completed Goals
- Prototype II
- Beginning Tests for Deployment, Fit
- ImagineRIT
- Have made every part once!
Anthony, System Integrator
- Printing Tests: Helped with printing, painting and assembling the final system
- Wire making practice: Figured out a lot of ways to not make the deployable hot knife and gave feedback on design revisions
- Logistics: Placed orders, helped clean up drives, applied for ImagineRIT
- Fit and Assembly Testing: Helped put together the structure and find potential issues
Paul, Deployable Mechanism Designer
- Machining Tests: On rail configuration and assembly practice
- Printing Tests: Test shapes, and bottom plate
- Design work: Deployment Switches, Final Revisions, Final Simulations for Vibration and Steady State Thermal Conditions
- Simulation work: Final Simulations for Vibration and Steady State Thermal Conditions
- Rail machining instructions
- Fit and Assembly Testing: Assembly and test the fit of components
- Design Review: Reviewing Design for improvements, basic research testing
Rob, Structures Designer
- Machining Tests: On rail configuration and assembly practice
- Printing Tests: Test shapes, and bottom plate
- Design work: Deployment Switches, Final Revisions, Final Simulations for Vibration and Steady State Thermal Conditions
- Simulation work: Final Simulations for Vibration and Steady State Thermal Conditions
- Fit and Assembly Testing: Assembly and test the fit of components
- Design Review: Reviewing Design for improvements, basic research testing
Tristan, Deployable Device Designer
- Printing Tests: Test shapes, and bottom plate
- Table Top Deploy: See if prototype will properly deploy
- Fit and Assembly Testing: Assembly and test the fit of components
- Spring Tests: See if the springs are correctly made and ideal for our work
- Design Review: Reviewing Design for improvements, basic research testing
Assembled Prototype
For this review we printed an entire prototype out of ABS plastic. This prototype lacks thermal, mass and strength properties of the final product. Despite this, we were still able to test assembly and deployment and find necessary design changes.Design Updates
Some changes were made in the design of the rails to account for hardware. Holes were added in the ends to allow assembly of the plunger spring and deployment switch.
Simulation Verification
Vibration
To validate our vibration simulation techniques used in MSD Phase I, we spoke with a subject matter expert from the mechanical engineering department. After reviewing our procedure with Dr. Ghoneim, he agreed that we had accurately represented the launch conditions, assuming our design does not contain any loose parts.Acoustic vibrations are not a concern for our design due to the fact that the acoustic pressure is minimal, and the materials we used have strong damping characteristics.
How will thermal expansion affect the clearances in our hinge mechanism?
Based on calculations from our nominal hinge size, and Ultem's low thermal expansion coefficient of 65e-6 m/(m C). Even across the entire operating range of the CubeSat from -40 to 40 C, the critical hinge dimensions will change by less than 0.0005" this small change in dimensions will not adversely affect hinge performance.
Ultem High Temperature Performance
Assembly Instructions
The idea is to machine the rails first, assemble the deployable structure on the hub plate and the pre-assemble the hot plate and insert it.
Procedure for Machining Rails
- Obtain Aluminum Stock of size 0.75” x0.75” x4.5”
- Mount part in milling machine
- Square off end of part and two sides
- Machine to expose Face 1
- Rotate part 90 deg along major axis and machine to expose Face 2
- Flip part and mill to length
- Machine to expose Faces 3 and 4 as before
- Mount part on sine fixture and machine the tapered feature
- Mount part to machine Face 5
- Mount part vertically and machine all holes in each end
- Re-orient part and machine to expose Faces 6 and 7
- Drill remaining holes
- Rotate part 180 degrees and mill to expose Face 8
Procedure for Printing Ultem Components
- All 3D printed components are printed using Ultem 9085
- Print all parts in an orientation such that their face farthest from the CubeSat center of mass is facing downwards
- Gently file all faces that experience contact with another component to remove dimensional variations caused by the printing process
- Verify all dimensions critical to the results of the fit test, especially contact points at aluminum rails
Test Results Summary
Test PlanTable Top Deploy
This test involves deploying a prototype CubeSat in a lab ambient setting. The NiChrome hot knife's ability to cut the restraining line, the springs' ability to deploy the panels and the ability of one hot knife cut to free both panels were all tested. ER5 - Time from command to deploy, is tested.Test Plan
Videos of Test
Results
This test was a partial success. The hot knife was able to sever the restraining line. The springs were able to deploy the panels once the restraining line was free. However, the restraining line became stuck in its routing and the second panel did not deploy.The time from command to deploy was 4 seconds which satisfies ER-5 which requires the deployment to happen 8 seconds after the signal is received.
Takeaways
After this test, we are comfortable with our design of the spring-high system and the hot knife. Modifications to the path of the restraining line will be made to reduce the likelihood of it becoming stuck.Fit Test
This test involved the checking the CubeSat dimension wise for both clearance and protrusion space. The CubeSat has to fit in the PPOD and abide by other constraints. This test satisfies ER-4 protrusion space, and ER-8 CubeSat clearance.Test Plan
Photos of Test
Results
Takeaways
- The test procedure was developed and fine tuned for when the fully assembled CubeSat structure is available.
- There was a lot of failed test dimension, but this was expected due to not having it properly assembled with fasteners. Also due to parts not made out of the correct material along with the correct dimensional accuracy.
- Learned that when machining rails to leave extra material on the outside so that once assembled the rails could be machined down to the correct assembly tolerance.
- This test will need to be performed both before and AFTER running other tests such as the P16103 vibration test. Due to machining the rails down to the correct tolerance it is natural to check dimensions after potentially altering tests.
Current Design Package
Upon 3D printing Prototype II, installation of the spring showed drifting off of the lifted tabs. So to ensure that the spring deflection is consistent retaining blocks were added which is shown above.Current Design Weighs 360 grams, with 5 50 gram solar panels attached, indicating a total system mass near 145 grams.
Ordering Status
Many of our components have been finalized in the past few weeks and all updates to the bill of materials and our status in obtaining them are shown below. Most notably, we have settled on our method of obtaining Ultem. Stratasys has suggested they can print our components for free provided we share our results with them. This assuages our budgetary concerns and gives us more confidence in our ability to print in Ultem in a reasonable time frame.Risk and Problem Tracking
Risk Assessment
The new plan to outsource printing to Stratasys reduces the severity of the risk of RIT not being able to print in Ultem. While it would still be good to have Ultem printing in-house for spot fixes and future production, the project can survive without RIT doing the printing.Problem Tracking
We have made significant strides in mitigating the problems that were facing our project. Most importantly, we have found a source of affordable, high quality Ultem printing in Stratasys. Initial prototype assembly has also allowed us to eliminate concerns we had about aluminum stock being too small and hinge springs being too weak.Obtaining Ultem
The biggest issue of this phase has been obtaining Ultem with which to print. Our original plan was to order Ultem from Fisher-Unitech but we discovered we are out of their ordering range. Alternatively, we tried to order Ultem from Stratasys but they were reluctant to sell filament directly to us. Due to the importance of obtaining printing material, we have developed several alternatives and backups.Delrin Printing
During our material selection phase, Delrin was our second choice to print in. Due to the issues that have arisen with Ultem printing, the use of Delrin as a material was reconsidered. Delrin is relatively cheap and easy to purchase, costing only $50 for a 1kg spool of filament. Delrin also has the advantage of having similar physical properties to Ultem so that some testing, and even the final product, could be made of Delrin if absolutely necessary. Despite the similarity in mechanical properties between Delrin and Ultem, if the final product were to be built in Ultem, Delrin tests would not give us as much confidence in the viability of an Ultem CubeSat as if we used the real thing during tests. Dr. Cormier has also expressed reluctance to print in Delrin due to the potential toxicity of the material at high temperatures. Because of these drawbacks, we consider printing in Delrin to be an inferior option. Delrin printing will not be considered again unless we are unable to purchase Ultem from a third party out of state.Alternate On Campus Print
A Fortus 360MC is apparently in the Golisano College of Computing and Information Sciences. A previous group has printed with Ultem on campus on this printer this is the link to their home page. The group created a device that required the use of Ultem 9085 to 3D print their parts. Documentation would suggest that their is a printer on campus. Previous senior design team (P15611) that printed with Ultem was contacted. Their printing was not done on campus but rather with Caldwell manufacturing which they had a relationship with.Stratasys Sponsorship
In our search for more Ultem sources, an Ultem distributor recommended us to the Stratasys sponsorship program. He felt that our unique project may be something that Stratasys would be interested in supporting. We have applied to the program and are waiting for a response in the coming days. This would give us the ability to print our Ultem parts for free. In exchange for this service, they would like us to share a report of our project and how Stratasys was able to help us create our parts.Outsourcing Quotes
Incept3d-$650, 2 Weeks Lead Time
Resource Plan
Plans for next phase
Deliverables
- Manufacturing (Paul, Anthony, Rob)
- Machining Rails
- Outsourcing Ultem through Free Program and Stratasys
- Building Boilerplate Solar Cells and Test Mass
- Begin Testing(Tristian, Anthony, Rob)
- Fit II
- Bench Deployment II
- Full System Creep
- Time to Remove
- Resolve HAB Flight Opportunity
- Logistics
- Apply to Conferences
- Finish ImagineRIT Application
ImagineRIT
Application 666 made for our project, Will be working with RIT SPEX to set up COS Hallway for Space Systems. ===Home | Planning & Execution | Imagine RIT
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