ROTOTILT

Robert RessBryce 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.

PROBLEM APRAISAL PHASE

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 desiredfeatures, operating conditions, and design constraints. Importantoperation conditions included the ability to operate under a one-poundpayload 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

DESIGN REQUIREMENTS

ENGINEERING REQUIREMENTS

Overall Weight Displacement Tolerance Factor of Safety Number of Materials Revolution Rate Cost Overall size Number of Controls Number of tools Strength

ENGINEERING TARGETS

ENGINEER REQ. TARGETWeight < 25 lbsDisplacement Tolerance .5 degreeFactor of Safety >1.5Number of Materials 3Revolution Rate 2 rpmCost 500 or lessOverall size < 3 cubic feetNumber of Controls < 5Number of repair tools 3Strength < 90% of yield

COMPETITIVE BENCHMARKS

3D DIGITAL VELMEX

HOUSE OF QUALITY

Strong Laser Table (Our Project)

Medium 3D digital Corp.

Weak Velmex

o Rototilt (our 2nd design)

Weig

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Dis

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Fact

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afe

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Num

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ate

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Revo

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ate

Cost

Ove

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Siz

e

Num

ber of C

ontrols

Num

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epair to

ols

Strength

lbs deg # # rpm $ ft̂ 3 # # psi 1 2 3 4 59 Smooth Operation all6 Two D.O.F (rotary table) 4 Portable 8 Controllable Displacement all6 Holds part (clamp) 6 Easy to use all8 Rigid build (handles abuse) 6 Laboratory Use all8 Reliable all8 Mates with existing Laser 7 Has mounting table 3 Easy to repair 4 Attractiveness 9 No damage to scanner all8 low cost

Laser Table (our product) 25 0.5 1.5 3 3 500 3 5 3 < .8*max

3d Digital Corp 32 0.1 NA 3 NA 20,000 4 4 2 NA

Rototilt (our 2nd design) 10 0.5 800 3 2 <300 1 2 3 0.13%

Velmex 6 0.1 NA 3 NA 1500 1 1 2 NA

TARGETS (Delighted) 30 0.5 1.5 3 2 700 3 6 3 >.9*max

Laser Table (Our Project) 3D digital Corp. Velmex Rototilt (our 2nd design)

Direction of Improvement

Perform

ance

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Imp

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Units

BENCHMARKS

Usa

bili

ty

TECHNICALREQUIREMENTS

CUSTOMER REQ'S

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)

CONCEPTUAL DESIGN PHASE

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

Telescoping laser mount

Dovetail Slider2nd DOF Mechanism

Unified Assembly

SKETCHES: THE CHOSEN CONCEPT 4

Lowest Cost

Easiest to Machine

THE ROTOTILT

CONCEPT EVALUATION

IDENTIFICATION OF FAILURE MODESFailure 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.

1 152 123 74 75 106 87 98 99 710 611 10

0.91

0.90.9

0.660.580.740.82

0.90.620.90.74

0.580.50.620.82

Negligable Operating NoiseSatisfaction (%) 75.52 80.3

0.68 0.68

Conrollable (Accurate Displacment)Easy to OperateReliable UsageLow Weight

Easy to MaintainEnvironmental InsensitivityLow CostPart Clamping Ease

Rotary Table mounted 2nd DOFMech. Table /Telescoping LaserSmooth OperationPortable

0.90.58

0.740.66

Criteria ImportanceElect.Table/Solid Shaft Laser Mech. Table / Solid Shaft Laser

0.90.950.80.80.90.90.91

0.90.950.9

92.6

AlternativesConcept 2Concept 1 Concept 3 Concept 4

0.90.660.660.580.740.820.91

0.90.90.883.9

PRODUCT DESIGN PHASE

PRODUCT DESIGN

Based on our concept parts were modeled using Pro-Engineering

1. Lock-side shaft2. Lock-side Leg3. Thumb Screw Lock4. Clamp Bolt5. Clamp6. Model Plate7. Leg Mounting Bolts8. Rotary Table T-slots9. Rotary Table10. Rotation-side Leg11. Rotation-side Shaft12. Degree Indicating Dial13. Rotation Knob

MATERIAL(S) SELECTION

Aluminum was chosen as the material for all the pieces that were to bemachined 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.

PRODUCT EVALUATION PHASE

F.E.A

LegShaft

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

Component FEA Max σ yield of aluminum (psi) % of yield Safety factorshaft 66.19 50000 0.132 755leg 5.084 50000 0.010 9835

plate 6.531 50000 0.013 7656

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 askedfor a bigger budget so as to incorporate an aesthetically pleasing component to the build

DEMONSTRATION

ANY QUESTIONS?