Team 04025 Preliminary Design Report
Optical Stage Redesign
Design and Fabrication of an
Optical Stage Redesign
Critical Design Report
Team 04025
Adam Pruyne, ME – Project Manager
Nate Smith, ME
Andrew Gallagher, EE
Dr. Risa Robinson – Mentor and Customer
Dr. Alan Nye – Project Coordinator
Department of Mechanical Engineering
Kate Gleason College of Engineering
Rochester Institute of Technology
76 Lomb Memorial Drive
Rochester, NY 14623-5604
Executive Summary
This report summarizes the progress made by the Optical Stage Redesign Team. The majority of this report was previously presented during the PDR phase of the project with exception to chapters six through nine which highlight devleopment, assembly and testing efforts since that time. The goal of this project is to design and manufacture a test apparatus to facilitate the research of particle flow dynamics in the human lung. Due to the complexity of the seven generation lung model, the apparatus must be designed to overcome many challenges to the Particle Image Velocimetry analytical process. Primarily, the apparatus must allow full, unobstructed, analytical access to all flow passages. To do so, the apparatus must be designed with several degrees of freedom of movement as well as minimal contact with the model.
A multi-faceted approach to new product development was used to redesign the optical stage. Transitioning through the first six chapters, the team is successfully poised for completion of the Preliminary Design Review. The first chapter of this report outlines the steps taken to identify and clarify the needs as well as the background for the project. The second chapter presents the methodology used for developing concepts to accomplish the goal of the project. The third chapter examines the technical, financial and schedule feasibility of each concept culminating in a final design recommendation. It is in the fourth chapter, that specific design criteria are identified and a set of performance goals are developed for the project. The fifth chapter outlines design concerns and presents analysis and justification for the design methodology taken by the team. The last several chapters outline the experiences involved with the manufacturing, development and testing of the Claw assembly. In addition, a chapter is included that provides design improvement recommendations to further improve the Claw design. Lastly, a conclusions chapter is included and represents the general overall impressions that remain after participating in this project.
Through this process the optical stage redesign has evolved through many different concepts to a final configuration that is technically sound and robust. Using a combination of screw-actuated slides and existing materials, all passageways of the lung model are analyzable and all other performance requirements have been achieved.
The final configuration of the optical stage redesign, including all supporting mathematical analysis, delivery schedule and budgetary considerations as well as manufacturing drawings are included in the technical data package. The package has both assembly drawings as well as part drawings
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Team 04025 Preliminary Design Report
Optical Stage Redesign
Table of Contents
Executive Summary 2
Table of Contents 3
1 Recognize and Quantify the Need 4
2 Concept Development 10
3 Feasibility Assessment 15
4 Design Objectives and Performance Specifications 17
5 Analysis of Problems and Synthesis of Design 21
6 Prototype Development 30
7 Test 34
8 Future Design Considerations 36
9 Conclusion 37
10 Acknowledgments 38
Figure 1 - The Gyroscope Concept 12
Figure 2 - The Ring Concept 13
Figure 3 - The Globe Concept 14
Figure 4 - The Claw Concept 15
Figure 5 - Torque Analysis – Cantilevered Loading Implications 26
Figure 6 - Torque Analysis - Positive Locking Mechanism 28
Figure 7 - Clamping Block Modifications 31
Figure 8 - Keyway Modification 32
Figure 9 - Model Support Modifications 34
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Team 04025 Preliminary Design Report
Optical Stage Redesign
1 Recognize and Quantify the Need
Aerosol research is a growing field of study in today’s biotechnology industry. Understanding particle dynamics within the human lung could lead to more effective treatment of pulmonary diseases such as asthma, tuberculosis and COPD. Additionally, understanding how particles behave with in the human lung could lead to new methods of treatment for diseases such as diabetes or how to safe guard against airborne contaminants such as cigarette smoke and biological weapons.
Currently, there are experiments taking place at the Rochester Institute of Technology with the expectation of gaining insightful knowledge into these particle flow dynamics of the human lung. Using a technique known as Particle Image Velocimetry (PIV), velocity profiles are being mapped through an ideal three-generation lung model. Knowing the velocity profiles for this ideal case is only the first step toward greater understanding.
To gain in-depth knowledge of particle flow dynamics in the human lung, a seven-generation cast replica of a thirty-four year old male subject, must be tested. The current experimental test set-up is poorly equipped to handle a model of such complexity. As a result, a more versatile test set-up must be constructed that will provide access to the many additional bifurcations as well as meet several performance criteria as specified by the customer.
The mission of this project is to create an experimental test set-up that will meet or exceed the expectations of the customer. Consideration will be given to every detail. Utilizing knowledge gained through study at the Rochester Institute of Technology the proposed design concepts will be thoroughly scrutinized and a concerted effort will be utilized to achieve excellence in design and reliability.
To be able to effectively implement the mission, the characteristics of the project must be described. The optical stage redesign employs multiple positioning mechanisms including three translational slides and one rotational platform. Each of these positioning mechanisms is capable of an infinite number of positions and therefore the operator is unlimited in the positioning of the lung model. Additionally, the lung model is capable of limited rotational motion about its axis. As a result of the positioning mechanisms and the partial lung rotational motion, multiple degrees of freedom of movement are achieved.
A motorized camera focus has been incorporated for operator convenience. The operator will no longer have to move from the PC workstation to the apparatus to adjust the lens focus. The motorization of the camera focus will occur at the PC workstation.
All mechanical components of the optical stage redesign have been chosen to provide sufficient design margin and mechanical stability. Angle brackets and strengthening gussets have been incorporated to prevent deflection and twisting of extension arms due to cantilevered loads. Materials for manufactured components have been chosen for strength and to minimize bulkiness. Electrical components have been chosen for their durability and performance.
A major objective of the project is to retain focus on, and to work within, specific overall scope limitations of the project. One of the most important of these scope limitations is regarding project documentation. Upon successful completion of this project, the optical stage redesign team shall provide the customer with all necessary analysis, documentation and data acquired during the redesign effort. Additionally, the scope limitations include working within a set budget and schedule. The project shall be completed with in the specified budget of $2000 and be delivered in a timely manner starting with the Preliminary Design Review in November of 2003 and the Critical Design Review in May of 2004.
There are certain individuals or groups of individuals, called stakeholders, which stand to benefit greatly from the successful outcome of this project. The primary stakeholder has been identified as Dr. Risa Robinson, Assistant Professor of Rochester Institute of Technology. The secondary stakeholders have been identified as Dr. Mike Oldham of the University of California, the Mechanical Engineering Department of Rochester Institute of Technology and the biotechnology and healthcare industry.
Beginning with the end result in mind, the key business goals of a project provide a picture of the global effect that the successful completion of this project could provide in the business sector. The key business goals, for the optical stage redesign effort, have been established. With the success of this project there will be opportunities to contribute to advancement of medical knowledge and as a result, many additional opportunities, both financial and research oriented, could become available to either the team members or the Institution.
To ensure that the project will meet financial objectives a preliminary analysis has been conducted. As mentioned previously, the overall budget for the optical stage redesign is $2000. Based on extensive research and assessment, there have been several major cost concerns identified. Two optical stages, each at a cost of $440, must be purchased. At least one motor and other electrical supplies must be purchased in an effort to supply the motorized camera focus function. These electrical supplies are not expected to exceed a cost of $250. Other miscellaneous materials such as an assortment of fasteners and angle brackets and gussets are estimated to cost approximately $100. Manufactured components are not expected to exceed $200 as much of the machining will be completed in-house. The remainder of the apparatus materials will be supported with in-stock fixturing where applicable.
It is important to establish, from a business standpoint, what represents the primary and secondary markets for the optical stage redesign. To do so provides additional insight into the impact of the successful completion of the project. Although there is no primary market for the apparatus itself, the resulting research will be very valuable to the healthcare industry. Providing a better understanding of lung dynamics will facilitate cheaper and more effective treatments for patients that suffer from a number of illnesses including asthma and even diabetes.
Considered a secondary market, the research sector could advance significantly with a better understanding of particle dynamics in the human lung. Future opportunities for experimenting with more complex models will be possible with a versatile design. It is expected that future graduate studies will proceed using this apparatus based on the versatility of the final configuration of the optical stage redesign.
There are certain aspects that are considered an “Order-Qualifier” and those that are considered an “Order-Winner”. Order-Qualifier aspects of the project are those that meet the customer’s basic requirements. The following have been identified as the project’s Order-Qualifiers:
- The test-bed must support a flexible, translucent model with minimal contact points.
- The test-bed must supply a minimum of three-axis rotation and translation. Rotational freedom need not exceed 90 degrees in any axis. Translational freedom must allow for three to four inches of travel in all three axes.
- Resolution of rotational and translational adjustment must be fine enough to secure and positively lock the model at angles of ± 0.5 degrees and translational distances to within ± 0.005 inches.
- The test-bed must be able to supply liquid flow to the model via one inlet and multiple outlets. This supply must not inhibit rotational and/or translational motion.
- The test-bed must ensure that the light sheet generator (LSG) and the digital video camera remain in a two-dimensional plane and at 90 degrees to one another at all times.
- The platform for both the camera and the LSG must be adjustable and maintain the ability to be positively locked into position.
- The vertical motion platform for the camera must be able to be adjusted while monitoring flow at the PC workstation.
Order-Winner aspects of the project are those that exceed the customer’s basic requirements. As the project is a relatively simple one, it is difficult to identify many Order-Winners. Along with this fact, the following project Order-Winners have been identified:
- The test apparatus will improve user “friendliness” by requiring minimal tools to adjust position of the model/PIV equipment position.
- The project is estimated to cost several hundreds of dollars less than the proposed budget.
- The durability of the test set-up is superior to the existing set-up.
- The compact and simple design of the apparatus permits easy teardown and set-up for movement to other research locations.
- Movement of the Fiber Optic Cable will be minimized.
The ultimate goal of the optical stage redesign team is to provide a fully functional, multi-axis experimental test set-up that is capable of meeting or exceeding all of the customer’s requirements. The team has agreed to these requirements as stated in the prior paragraphs of this document. The team shall endeavor to include, as a minimum:
§ A completed test apparatus that addresses the Order-Qualifiers objectives as presented in previous paragraphs of this report.
§ A Technical Report chronicling the product development philosophies utilized in the design of the apparatus.
§ This technical report shall also include financial and future schedule information. This financial and schedule information will provide a clear justification for component selection and cost.
§ A Technical Data Package that includes manufacturing and assembly drawings as well as supporting analyses, delivery schedule information and a financial Bill of Material.
2 Concept Development
During the concept development phase, a technique known as brainstorming was used to fabricate a long list of design concepts. The philosophy for the long list was not to arrive at the final solution but to build a roster of possible candidates regardless of feasibility. Once the long list was created, an informal process of eliminating concepts was employed to create a short list of more feasible candidates for the final design. Concepts were down-selected if they obviously exceeded the scope of the project or were not able to meet all of the customer requirements. The short list consisted of three promising concepts.
The three final concepts were then modeled in Pro-Engineer CAD software. This step was completed in an effort to give validity to the short list concepts. By modeling the concepts in a three-dimensional CAD package, the advantages and limitations of each concept are exposed. This process of three-dimensional modeling facilitated the feasibility assessment that will be discussed in future chapters of this report.
To ensure that all detailed components and purchased parts are accounted for, preliminary Bills of Material (BOM) were created for each concept. Although it is anticipated that the machining of components will be completed in-house, a machine shop was contacted for estimated material and labor cost for parts that required intricate machining beyond in-house capabilities. Vendors or their internet websites were contacted for pricing sheets and specifications for any purchased hardware that was necessary. The result of this effort was a reasonably accurate preliminary financial assessment for each concept.