Preliminary Detailed Design
Additional Notes for Preliminary Detailed Design Phase
Due to the fact that the overall goal for this project changed during the coarse of this phase, our EDGE page will look different than previous years. Some sections are to be determined, and documents will be uploaded when the work is completed.
Team Vision for Preliminary Detailed Design Phase
Going into the Preliminary Detailed Design Phase, the goal was to develop a prototype and perform analyses to verify the design’s stress mitigation on the lens. Feedback from the System Design Review led us to pursue a Push-Pull solution. We decided on two priority objectives:
- Determine an effective way to “pull” the lens from the top
- Determine a method to interface/adhere the pulling method onto the lens so that the pulling forces would transition into the lens.
In order to successfully work through this phase, our team researched current industry solutions, and brainstormed push/pull solutions and “adhesion” methods. A follow up meeting was scheduled to obtain feedback on two paths that we considered for implementing the pulling forces into the lens:
- vacuum pump seal
During this meeting we were advised that it would be best to focus on a high aspect ratio (very thin) lens solution, which would be problematic for either option due to small circumferential surface area. The change was due to upcoming work orders for high aspect ratio lenses and because of a recently developed solution for larger lenses with moderate to low aspect ratios (that we were previously focusing on). However, the current solution was highly expensive to produce and will most likely remain one of a kind. Overall, the new scope focuses on creating a fixture and characterizing the known stress inflicted by the fixture to be able to back out the actual deformation present in a lens. The specific lenses in question have 10”-14” diameters and high aspect ratios (exact range to be determined). It is desired that the solution be simplistic in nature, cost effective, relatively easy to manufacture, and more universal.
Before Goal Change
Decisions After Design Review
After coming out of the Systems Design Review, our team decided to pursue a horizontal Push-Pull mount inspired by the ASML Lithography Corporation in Wilton Conneticut. More details are outline in the "Opto-Mechanical Systems Design: Design and Analysis of Large Mirrors and Structures", 4th edition, Volume 2.
Roder, Paul and Vukobratovich, Daniel. Opto-Mechanical Systems Design: Design and Analysis of Large Mirrors and Structures, Fourth Edition, Vol. 2. 4th ed. CRC Press, 2015, pp. 136.
To continue improving our design, and to not forget the fact that the original customer requirements required the mount to be for horizontal and vertical oriented mirrors, more research regarding vertical oriented mounts was included.
However, it was also confirmed coming out of the system design review that we should focus more on horizontal configuration mounts. We needed to focus on horizontally oriented mounts because there is a "backlogging" effect i.e. a lack of horizontal mounts which slowed production.
Roder, Paul and Vukobratovich, Daniel. Opto-Mechanical Systems Design: Design and Analysis of Large Mirrors and Structures, Fourth Edition, Vol. 2. 4th ed. CRC Press, 2015, pp. 142.
Roder, Paul and Vukobratovich, Daniel. Opto-Mechanical Systems Design: Design and Analysis of Large Mirrors and Structures, Fourth Edition, Vol. 2. 4th ed. CRC Press, 2015, pp. 143.
Roder, Paul and Vukobratovich, Daniel. Opto-Mechanical Systems Design: Design and Analysis of Large Mirrors and Structures, Fourth Edition, Vol. 2. 4th ed. CRC Press, 2015, ch. 4.
Subject Matter Expert Meetings
In order to gain more inspiration for our design, the team set up a meeting with Jack Kelly, a researcher at the University of Rochester's Laser Lab. He was referred to us by Robert Kremens, a research professor at the RIT College of Imaging Arts and Sciences.
|Date||Contact||Credentials||Summary of Meeting|
|02/27/2017||Robert Kremens||Research Professor at Center for Imaging Science||
|03/08/2017||Jack Kelly||University of Rochester Laboratory for Laser Energetics||
Jack Kelly was kind enough to show us some of their modified AeroTech Mounts. Pictures are supplied and include some of the key factors we took into consideration in our brainstorming phase.
Jack Kelly also showed us around to one of the largest laser configurations built in the lab. He highlighted how their large mirrors were held together with adhesive. No pictures are provided, however we also took that into consideration in our brainstorming phase.
Adhesives ResearchIn order to see if adhesives could be applied to connect the "push-pull" mount to the lens, more research was conducted with regards to general marketplace adhesives.
|Double Sided Tape||Spray Adhesives|
Brainstorming & New Concept Generation
After we compiled all of the data and outside inspiration, our team tried to focus on solving two key problems:
- How are we going to push/pull the lens?
- How are we going to attach the push/pulling mechanism to the lens?
We generated the following concepts from our 2nd brainstorming iteration, continuing the pattern from the Systems Design Review.
Feasibility: Prototyping, Engineering Analysis, Simulation
Large Circular Ring
The team realized that a lot of our brainstorming designs involved some sort of "ring" which encompassed the lens. In order to test the feasibility of a majority of our designs, we decided to ask the machine shop to create a large circular ring from various scrap metal.
We learned two things from the prototype:
- It is hard to manufacture perfect circles with the correct radius.
- The base provided helped us to explore more "attachment" options which could be added to the "base circular design" in order to provide a more detailed design.
Another idea the team explored was the possibility of pursuing a ferromagnetic material which would help push/pull the lens for the correct stress profile.
However, the experiment could not be performed because we did not have access to the correct materials.
It was later learned after the preliminary design review that Company X uses ferromagnetic material as a waste product in their production lines. However, pursuing a sustainable/reusable solution is not within the time constraints of the project. Company X suggested that this could be a "Version 2" that can be added to the base design in future generations.
After the Systems Design Review, it was made clear that the FEA simulations for our concept design is critical deliverable. As a result, our team decided to start learning the FEA Solidworks package early on. Below are some examples of assembly simulations we tried to run for one of our brainstorming concepts.
We later sat down with one of the employees from Company X and learned the specific process uses in order to create FEA solidworks simulations. See Detailed Design Private for more information.
Throughout our entire process, our team kept hitting a wall with trying to solve one of our sub-problems. Our team went back to the functional decomposition and, again, we were trying to solve one distinct sub-problems:
- How are we going to attach the push/pulling mechanism to the lens?
We came up with two solutions to the problem:
And we didn't know which solution was better. So, we decided to consult Company X to see which path we should go down.
Our biggest concern was: how were going to attach our "push/pull" mechanism without breaking the lens?
During the meeting, we learned that neither solution would work due to a change in the company's needs. A new solution was made in the previous weeks which fulfilled all of our previous customer requirements.
Company X asked us if we could change our scope and focus on creating a new horizontal solution for high aspect ratio parts. We said, "Sure! We still have like 6 weeks and we don't want our project to turn into a paper weight. Let's build something that you can use!"
In response to this, we asked them to review the following customer requirements and re-rate them in terms of importance.
After Goal Change
New Goal: Create a “new solution” that can give a “good enough” stress profile but is more manufacturable that focuses on high aspect ratios!
After we learned of the goal change, the first thing the team did was return to company X to gain inspiration on their solutions for high aspect ratio lenses.
The information is classified and can be found in the picture below.
Concept GenerationAt the same time as we were getting into gear conducting technician's input, we also generated some simple concepts which we hoped to lead us down the right path in this trying to solve this new problem. This information is proprietary and cannot be access by outside personnel.
Feedback Concept Generation
The general feedback from the designs was the following:
- Both design would create a "non-uniform" pressure distribution.
- The pneumatic tube or teflon solution would never "settle". Even the slightest vibrations would disrupt the results from the interferometer.
- Liked the idea of adapting or a resizing chuck to different diameter's idea.
- Liked the idea of adapting the "Walking Donut" fixture to a larger design with incorporating it with different diameters.
- Disliked the immersion fluid idea.
We never anticipated the "settling" or "vibration" problem, so our team and Company X decided it was best to pursue a solid mechanical interface solution.
The full technician interviews document can be found here: //private/FullTechnicianReview.xlsx.
Final Design Selection
After consulting with Company X after the Preliminary Design Review, the team was down to two options:
- Using a sort of immersion fluid tank to suspend the lens in a horizontal configuration.
- Using a previously created solution but on a larger scale.
Due to time constraints and company preference, the team decided to pursue a larger scale of a previously created solution with the following abilities: adapting it to larger size lenses in the "feet" and adding a tilt adjustment on the "top slider".
A picture of the general final design is classified and can be found in the link below. The idea is based on a Company X and is proprietary.
We also learned that the requirements for the transmission test was unnecessary due to time constraints and the changed scope in the project.
Risk AssessmentHere is a version of our updated Risk Assessment.
Plans for next phase
- Improve upon this Design.
- Implement Walking Donut Design into Solidworks.
- Perform IE and FEA analysis.