SpaceX
During my first co-op at SpaceX, I worked with a team of Manufacturing Engineers for Dragon Propulsion. I was responsible for the manufacturing of the Crew Dragon high-pressure propellant abort system including process design for orbital tube welding and pressure testing as well as laser scan inspection, defect analysis, and tooling design.
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I also worked on several process improvement projects to save the company money as more capsules are produced through the use of custom tooling and equipment.
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Tools Used: NX, Teamcenter, GD&T, Ansys, 3D Printing
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Note: All images are sourced online and are only to provide visual aid to descriptions.
Tooling Design
The Problem
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During welding of large tubing assemblies off the capsule, the ends have high amounts of deflections which prevents assembly mating on the capsule
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It is costly to cut and re-weld tubes on the capsule and there is risk of introducing foreign debris into the tubes which can ignite with the hypergolic fuel
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Ends must be less than .005” out of tolerance on several 6’ long tubing assemblies
Solution
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2 dozen tools were modeled in NX to mimic the end constraints of the capsule as well as constrain the tubing and flanges during welding
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Tools allowed multiple assemblies to be welded at the same time on the same table
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Utilized GD&T to create drawings and outsource the parts for machining
Result
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Tooling was used for building future capsules
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There was no deflection when mating the assemblies using the tooling on the capsule
SuperDraco Tubes I worked On
Example of Drawings Created
Defect Analysis
The Problem
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During welding and bending of tubes, the ends may be out of tolerance compared to the drawings and there may be weld defects
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Tubes and assemblies need to be bent into place when installed on the capsule which introduces additional stresses into the lines
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Weld defects introduce stress concentrations at joints
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Need to find out if the additional stress causes the tubing to fail during use
Solution
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The tubing assemblies were laser scanned into NX and compared with the CAD models to determine the amount of displacement at the ends
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ANSYS models were created for tube ends to calculate the stress of bending the tubes back in place
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Welds were x-rayed to check for defects
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ANSYS models were created for weld defects to characterize the KT factors compared to a nominal weld
Result
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Lines that would not yield were kept and lines that would yield were remade
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KT models were created for certain conditions to be referenced by other engineers
Example of Comparing Scan Data
Example Ansys Model
Process Optimization
The Problem
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K seal ports need to be polished to a high surface finish for sealing and it can take over a day to complete one port by hand
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There are over a thousand port surfaces on a capsule which takes up a lot of technician time
Solution
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A custom rotary tool with a 3D printable frame was designed in NX to increase the rate at which ports can be polished and to be able to get into tight corners in assemblies
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A set of polishing adapters were created to be used on all types of ports and interface with the rotary tool
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Utilized GD&T to create drawings and outsource the parts for machining
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Performed polishing studies and statistical analysis to ensure that they were safe for part use
Result
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One port could be polished in minutes comparted to the hours it would take previously
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Tools were used deemed to be safe for use and were implemented into the polishing process
K-Seal Port