P11552 DLP Prototyping System

Transcription

1 P11552 DLP Prototyping System Meeting Purpose: 1. Project Overview 2. Confirm Engineering Specs & Customer Needs 3. Concept Review 4. Review proposed design confirm feasibility and desired functionality 5. Generate further ideas Materials Reviewed: 1. Project Description 2. Customer Needs 3. Engineering Specifications 4. House of Quality 5. Functional Decomposition Function Tree 6. Concept Generation Benchmarking/ Morphological Chart 7. Concept Selection Pugh Chart 8. Concept Overiew 9. Proposed System Design Overview 10. Risk Assessment Attendees Professor Cormier IE Guide Professor Esterman IE Professor Bonzo IE Meeting Date: 1/14/11 Meeting Time: 8:00 AM Meeting Location: Meeting Timeline Start Time Topic 8:00 Project description 8:05 Customer Needs 8:10 Engineering specs 8:15 House of Quality 8:20 Functional Decomposition 8:25 Concept Generation 8:40 Concept Selection 8:50 Proposed System Design 9:05 Risk Assessment 9:15 Next Steps + Q&A

2 Project Description Project Overview: The aim of this project is to design and fabricate a projected image photopolymer curing R&D platform. The system will use a Texas Instruments digital light projector (DLP) development system to project black and white ultraviolet (UV) light images onto a film of UV curable photopolymer in order to selectively cure/harden the polymer. Students will therefore design and construct a liquid resin spreading system, an optics system capable of transmitting and focusing a suitably powered UV light source, and the software needed to slice a 3D CAD model into the individual black and white images to be cured. Major Deliverables Liquid Resin Spreading Sub-System o Prepares resin for each layer s curing process UV Image Projection Sub-System o Utilizes a DLP projector from Texas Instruments (pre-purchased) Control System/ Model Slicing Software o Device hardware control o Slices 3D model into 2D images for projector Enclosure for Sub-Systems Expected Project Benefits: Expansion of fabrication machines located in RIT s Brinkman Lab. Foundation to create DLP system that allows for multiple resin types (not currently commercially available). Showcase the creativity and technical abilities of RIT s Multidisciplinary Senior Design teams. Core Team Members: Donald Gleason Project Lead Ronald Dalheim Steven Szklany Matthew DeRosa Aun Kei Hong Dr. Denis Cormier Customer/ Project Guide

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5 Benchmarking Research has been done in some key design areas to help with concept generation and system level design. There are already some available commercially developed rapid prototyping systems on the market today that utilize photopolymer resins. These rapid prototyping devices were used to develop targets for our engineering specs. The other design areas examined were light application, software, platform motion and resin application. System Level Z-Corp Z-Corp is a commercially available DLP system. Machine uses a resin bath to apply new resin layers and a platform in the bath that lowers as model is created. The DLP projector is located above and shines on the surface of the resin bath. The material between the top of the resin bath and the top of the model is the material that will be cured by the image projected by the DLP projector and adhere to the model below. V-Flash V-Flash is a commercially developed rapid prototyping system that uses UV light to cure a photo polymerizing resin. Unlike Z-Corp, V-Flash hangs the prototype part from above and dips the part into resin. The UV light projects an image on the bottom, cures the layer, raises the platform, a doc blade is swept across bringing fresh resin, and then the process is repeated. Sub-System Level Software The software in our design is used to import a CAD model and then slice the model into layers. The layers will then be sent to the projector as each image represents 1 layer of curing. Cad software such as ProE and SolidWorks were compared. Both programs support.stl files so should be able to use both. 3D Slicer is a free, open source software package available for multiple platforms. The source code can be modified to meet user needs. Resin Application Resin application will be the largest contributor to layer thickness and compatibility with multiple resins. The system must be designed to handle a range of viscosities and to also accurately distribute a thin accurate layer of resin. Two techniques that are used in photo polymerizing resins are spray nozzle, bath, and laminated object. The bath is the technique used in the Z-Corp where the model sits below the surface of a bath and cures from the top surface to the model. The bath is the simplest device and uses the least moving parts. Spray nozzles would spray the resin in desired locations and the UV light would cure it as it sprayed. Laminated Object Manufacturing has a photo polymerizing material in a filament and the setup is similar to a film camera where there is a roll on one side of the platform with a fresh charge of resin and a roll on the opposite side collecting waste material. Motion Control Closed loop and open loop control system were considered for the motion of the platform and the resin applicator depending on the method we choose to use. There may also be a combination of open and closed loop systems. In situations where accuracy is more important a closed-loop system is desired to give feedback. Closed-loop systems provide information on position and velocity. Modern closed-loop CNC machines can provide resolution up to of an inch. Another part of the motion control design is the use of lead screws, servo motors and stepper motors. UV Light Application Some key factors of our project will be programming items such as cure time. There are some key factors such as source wattage and cure time. Calculations as well as testing will also be involved in determining these design features.

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