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Rapid Prototyping

October 03, 10, 2011

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Introduction

Product Design and Development Phase

Engineering Activities 3 distinct phases

Design Phase Prototyping Phase

Manufacturing Phase

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Major obstacles for massmanufacturing

Long lead time Shoe industry 6 months

Garment industry 6 months

Car Industry 3-4 years Airspace Industry 4-5 years (Boeing, Airbus)

Indian airspace 10-15 years (India)

Submarine 10-15 years Arjun MBT 25 years

Art to Part: As less as possible

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Why Rapid Prototyping?

Because product designers would like to have aphysical model of a new part or product designrather than just a computer model or line

drawing

Creating a prototype is an integral step in design

A virtual prototype(a computer model of the part

design on a CAD system) may not be sufficient forthe designer to visualize the part adequately

Using RP to make the prototype, the designer canvisually examine and physically feel the part andassess its merits and shortcomings

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Advantages and Disadvantages ofRP

Cost

Accuracy

Materials limited Time

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Introduction

Design Manufacturing

3 types of checks:

Form Check aesthetic, Fitness Check assembly, etc.

Function Check

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Product Design & DevelopmentCycle Block Diagram

Conceptual Design

Preliminary Design

Engineering Analysis

Detailed Design

Set of sketches e.g.styling

Specifications ofthe product

Total Design ActivityDrawings, BOM,Tolerances, etc.

Dimensions, materials,

Factor of safety,Performance Indices

Conceptual Design:Scanning also, as

very rarely the

Design is startedfrom blue

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Block Diagram contd.

Prototyping

Testing (Inspection)

Tooling

Optimization

Parts

Test Reports

Tooling - Molds,Dies, etc.

Release to Manufacture

Iterations, etc.are missingin the block

diagram

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Conventional Prototyping

Prototype is the first or original example of anartifact

that has been designed

that is a model or a preliminary version

that needs to be developed (evolving

model, developed, tested & so on severaliterations)

that will be manufactured on a mass scale

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Prototyping Methods

3 different methods

Manual Prototyping

Virtual Prototyping

Rapid Prototyping 4 aspects Inputs

Methods

Materials Applications Design

Engineering Analysis

Tooling and Manufacturing

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Tooling(A) Material Removal Processes (Subtractive Type)

Traditional Methods

Turning

Shaping, Planing

Drilling, Boring Milling, Hobbing

Broaching, Tapping

Reaming, Grinding

Requires tools and fixtures

Non-traditional Methods: ECM, EDM, USM, EBM, IBM,PAM, LBM, WJM, AJM, etc.

Both processes require tools and are subtractive innature

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Tooling(B) Net Shape or Material Forming Processes

Traditional Methods

Forging

Casting

Deep drawing Bending

Extruding

Die casting

Rolling

Non-traditional Methods: 3D Laser Forming, LaserBending, etc.

Tools are required in the form of moulds or tool anddie

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Tooling(C) Material Addition Processes

Traditional Methods

Welding

Soldering, Brazing

Tools required in the form of holding fixtures Non-traditional Methods:

Rapid Prototyping Processes

SLA, SLS, FDM, LOM, 3DP, BPM, etc

RP processes do not require tools and fixtures

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Rapid Tooling Processes To have multiple copies RT processes

Basically of the type casting, forging, etc. i.e.Formative traditional processes

RT Processes: RT Silicone Molding

Vacuum Casting / Forming

Spray Metal Tooling (TAFA)

Resin Transfer (Epoxy Tool) Molding

Investment Flask Casting

Investment Shell Casting

Special Sand Casting

RT batch size 50-1000, ,10,000 parts replica ofRP processes

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Terminology Rapid Prototyping (RP)

Solid Freeform Fabrication (SFF) Desktop Manufacturing (DTM) Freeform Fabrication (FFF) Direct CAD Manufacturing

Instant Manufacturing Layer Manufacturing Techniques (LMT) Material Deposition Manufacturing Material Addition Manufacturing Material Accretion Manufacturing Generative Processes / Generative Manufacturing

Processes (GMP) Time Compression Technologies (TCT)

Analogous to Laser Printer

As it requires CAD geometryessentially unlike other processes

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Classification Liquid-Based

Solid-Based

Powder-Based

Liquid Based

SLA

SGC

Solid Object Ultraviolet

Laser Plotter (SOUP)

Light Sculpting

Two Laser Beam Plotter

Solid Based

FDMLOM

MJM (Multi Jet Modeling)

Selective Laser Adhesive& Hot Press (SAHP)

Powder Based

SLS

3DPBPM

Multiphase Jet Solidification (MJS)

Direct Shell Production Casting(DSPC)

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RP Processes

Photopolymer

Photopolymer resinsensitive to light

cross linking takes

place Monomer to

Polymer

Thermal

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RP Processes

Controls MaterialsRP

Physical &Chemical

Information

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Historical Perspective1. 3D Maps / Topography (Topographical Maps)

Blanther 1892 used wax

Pareira 1940 cardboard

Zang 1964 transparent plastic sheet

Gaskin 1973

Matsubara 1974 thin layer of powder / refractory particles(graphite) coated with photopolymeric materials (acrylate) his goal to make a casting mold

DiMatteo 1976 sheet metal plates edges smoothened

Nakagawa 1979 blanking dies, press forming dies,injection molding dies

2. Photo sculpture

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RP Methodology1. To create a solid Model

2. Create RP Model

3. Evaluate form, fit & modify solid model

4. Create revised RP Model (Tested for form & fit)

5. Create tooling for functional part

6. Evaluate the part for the function

7. Modify CAD solid model & repeat Steps 1, , 6

8. Finalize the design

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Overview

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Prototyping

Prototyping or model making is one of the important steps to

finalize a product design. It helps in conceptualization of adesign. Before the start of full production a prototype isusually fabricated and tested.

Manual prototyping by a skilled craftsman has been an age-old practice for many centuries.

Second phase of prototyping started around mid - 1970s,when a soft prototype modeled by 3D curves and surfacescould be stressed in virtual environment, simulated andtested with exact material and other properties.

Third and the latest trend of prototyping i.e. RapidPrototyping (RP) by layer-by-layer material deposition,started during early 1980s with the enormous growth inComputer Aided Design and Manufacturing (CAD/ CAM)

technologies.

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Product Fabrication Approaches

Machining

Joining

Forming

LayerDepositionor Rapid

Prototyping

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RP uses layer by layer additive approach to build shapesRP systems use liquid, powder or sheet materials to formphysical objects

[Courtesy: Kai & Fai]

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Basic Principles of Rapid Prototyping


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Step 1: Solid Modeling and Tessellation

[Courtesy: Zeid]

Surfaces of the

CAD model aretessellated andSTL file is exported

Tessellation is

piecewiseapproximation ofsurfaces of CADmodel by using

series of triangles

S Sli i

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Step 2: Slicing


After selecting part deposition orientation, tessellated model

is sliced This information is saved in standard formats like SLC or CLI

etc.

S 3

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Step 3

Generation of Laser Scanning Paths or Material DepositionPaths

Deposition of Layers: various technologies for layerdeposition are used

Liquid based : Stereolithography

Powder based : Selective Laser Sintering

Solid based : Fused Deposition Modeling,Laminated Object Manufacturing, etc.

S 4 P P i

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Step 4: Post Processing

Post Curing

Removal of Support Structures

Finishing by Sanding, Polishing or Painting

G li d Ill t ti f D t Fl i RP

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Generalized Illustration of Data Flow in RP

STL (3D)Layer Information, SLC or CLI

3D CAD

3D Reconstruction

2.5D ReconstructionReverse Engineering

3D CAD2D CAD Drawing /Manual Outline /

Lattice Data

Point CloudData

Data acquiredfrom MRI /CT Scan

Geometric Data

Specification of MachineLayer Information

Machine Data Set

Process ParametersMachine Parameters

Auxiliary Geometry, Supports, etc.

Cl ifi ti f RP P

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Classification of RP ProcessesGenerative Manufacturing Process / Rapid Prototyping / Solid Freeform Fabrication

Solid Paste Liquid Gaseous

WireOne or multi-

Component powderFoil

Melting &Re-solidification

Fused Layer ModelingBallistic Part

Manufacturing

Cutting & GluingLayer LaminatedManufacturing

Cutting &Polymerization

Solid FormPolymerization

PolymerizationPaste

Polymerization Process

Solidification bybinder

3D Printing

Melting &Re-solidification

Selective LaserSintering

Polymerization

Heat

ThermalPolymerization

Lamp

Solid GroundCuring

Light of One Frequency

Laser BeamStereolitho ra h

HolographyHolographic

Interference Solidification

ChemicalReaction

LCVD

St lith h

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Stereolithography


R id P t t i A li ti

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Rapid Prototyping Applications Design

CAD Model Verification Visualization Object

Proof-of-Concept

Engineering, Analysis and Planning

Form and Fit Models

Flow Analysis

Stress Distribution

Mock-up

Diagnostic and Surgical Operation Planning

Design and Analysis of Custom Prosthesis and

Implants

R id P t t i A li ti

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Rapid Prototyping Applications

Manufacturing

Plastic Mold Parts

Vacuum Casting

Metal Spraying

Casting Sand Casting

Investment Casting

Die Casting

EDM Electrodes

Master Models

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Rapid Prototyping Products

Engine Manifold Valve

Medical Implant Electronic Packaging

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Complexity of Object to be manufactured is not a limitation in

Rapid Prototyping

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SL Model for resection template Silicon Implant molded from a tool

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