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R OTOTILT. Robert Ress Bryce Young Osinanna Okonkwo. I NTRODUCTION. The current project proposes to build a device that will secure and orient a model (Dental impression mold) for a process which creates a 3-D digital image by means of a laser lithography camera.
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ROTOTILT Robert Ress Bryce Young Osinanna Okonkwo
INTRODUCTION • The current project proposes to build a device that will secure and orient a model (Dental impression mold) for a process which creates a 3-D digital image by means of a laser lithography camera. • Multiple scans are the norm in the laser lithography process, the design will be used for repositioning the dental mold for successive scans. • The design needs to have a sequence of angular increments to add repeatability and control to the model positioning process.
CUSTOMER The unit will be used by the graduate students of the mechanical engineering department engaged in research in conjunction with the Indiana University School of Dentistry. Other customers for this design project include: • The Sponsor • The End User (Graduate M.E. Students)
CUSTOMER REQUIREMENTS Response to a questionnaire provided a solid groundwork of desired features, operating conditions, and design constraints. Important operation conditions included the ability to operate under a one-pound payload and to have safe operation in laboratory conditions. • Portability (Small size) • Stability • Multiple Degrees of freedom • Smooth translation • Controllable/measurable translation • Lightweight • Safe • Easy to operate • Easy to assemble • Easy to maintain • Affordable (low cost) • Minimize or eliminate Noise • Environment friendly
PROJECT BOUNDARIES For the project’s boundaries we identified the following: • Incorporation of the rotary table should simplify and offer more control over the orientation process. • The design should be a functional unit, which satisfies all customer requirements and accommodates for the existing laser. • The last major design boundary was the budget limit of five hundred dollars.
PROJECT OBJECTIVES The objectives of the design project are to create a unit that can perform the functions described earlier by: • Create a CAD model of device • Create a 2D drawings to enable manufacturing • Create a prototype
ENGINEERING REQUIREMENTS • Overall Weight • Displacement Tolerance • Factor of Safety • Number of Materials • Revolution Rate • Cost • Overall size • Number of Controls • Number of tools • Strength
3D DIGITAL VELMEX COMPETITIVE BENCHMARKS
ENVIRONMENTAL ISSUES • Our product will be constructed from recyclable materials (metal & plastic) • The mechanical design does not require power, and does not contribute to pollution • Not a mass produced product • Conversely, corrosive effects from the environment do not significantly affect the product (indoor use)
FUNCTIONAL DECOMPOSITION • Overall Function: Orientate and scan model
OVERALL CONCEPTS • Concept 1 • Mechanically operated system • Utilize existing rotary table design • Worm gear driven rotary table • 6 Total DOF • Concept 2 • Electrically operated system • Worm gear driven rotary table • 4 Total DOF • Concept 3 • Mechanically operated system • Spur gear driven rotary table • 4 Total DOF • Concept 4 • Mechanically operated system • Utilize existing rotary table design • 2 Total DOF (Excluding the camera)
SKETCHES – Concept 1 2nd DOF Mechanism Dovetail Slider Unified Assembly Telescoping laser mount
SKETCHES: THE CHOSEN CONCEPT 4 THE ROTOTILT • Lowest Cost • Easiest to Machine
CONCEPT EVALUATION IDENTIFICATION OF FAILURE MODES Failure modes were assessed by the group during this procedure. They included: • Table rotation gear damage • Table tilt angle failure • Clamping system failure • Electrical motor failure • The group determined that all concepts would be able to meet the requirements at this phase.
PRODUCT DESIGN Based on our concept parts were modeled using Pro-Engineering 1. Lock-side shaft 2. Lock-side Leg 3. Thumb Screw Lock 4. Clamp Bolt 5. Clamp 6. Model Plate 7. Leg Mounting Bolts 8. Rotary Table T-slots 9. Rotary Table 10. Rotation-side Leg 11. Rotation-side Shaft 12. Degree Indicating Dial 13. Rotation Knob
MATERIAL(S) SELECTION Aluminum was chosen as the material for all the pieces that were to be machined for various reasons, namely: • Light weight – the density is only 0.0975 lb/in3 • High strength • Good workability • Resistant to corrosion • Widely used in aircraft fittings, marine’s fittings, brake pistons, and hydraulic pistons.
F.E.A Leg Shaft Model Plate **Only one side was consider due to symmetry**
SUMMARY OF F.E.A RESULTS • FEA Analyses were carried out using PRO-E Mechanica • With a minimum factor of safety of 755, the team decided that further FEA analysis on this build would not be beneficial.
PRODUCT EVALUATION COMPARISON TO ENGINEERING REQUIREMENTS There are 10 engineering targets to be attained. The table below illustrates the targets and shows whether or not the design met the target. **Actual values were determined from FEA and Prototype Testing**
CLOSING • The final design produced is more than satisfactory. A very simplistic design, this product meets all engineering requirements and most of the customer requirements. • The Rototilt is very low cost • This design embodies rigidity and robustness • Also built into this product is ease of operation and assembly. • In finality, we can conclude that this project was a success. • If offered a chance to do this again, the team would have asked • for a bigger budget so as to incorporate an aesthetically pleasing component to the build
