additive manufacturing seminar 1 this is not a sales seminar!!! my purpose here is to share...

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•This is NOT a sales seminar!!!•My purpose here is to share information and educate

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•What is the term Additive Manufacturing mean?•Additive Vs. Subtractive Manufacturing

•In subtractive we start with stock and remove material to get the net shape (traditional machining)

•In additive we start with nothing and add material to get the net shape

•Our RP goal is to get the best quality parts, in the shortest possible time, at the lowest possible cost.

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Introduction of RP – Additive ProcessGenerate a prototype part by Layering

Manufacturing Technology - composite material layer by layer

Build in one step - directly from model to manufacturing

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Rapid Prototyping - definition(RP) is defined as a group of techniques used to

quickly fabricate a model of a part or assembly using three-dimensional computer aided design (CAD) data.

Rapid Prototyping ,also referred to as solid free-form manufacturing, computer automated manufacturing, and layered manufacturing.

RP has obvious use as a vehicle for visualization.

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Prototypes

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Evolution of Rapid Prototyping3D objects were used to demo model since early history

Mud, wood, clay and paper was used to create mockupsWith the industrial revolution machine tools were used to

create scaled models The digital era brought a leap step to advanced layer

additive prototyping and manufacturing Prototypes are made from solidified liquid, powder, sheets

and jetting materialsAdvanced materials are leading into the future of rapid

manufacturing techniques and technology

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Evolution of Rapid prototyping

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• Industry started in the mid 80’s• Around 30,000 products sold world wide.• Great achievements in machine performance and

model quality.• Fairly expensive technologies introduced up to date.• Every technology has it’s pros and cons.

The fathers of Rapid PrototypingIn the early 1980’s Charles Hall developed the liquid

polymerization based Stereolithograpy apparatus (SLA)

Granted the original patent Considered to be “ the founder” of RP In the late 1987, Carl Deckard developed the

powder based Selective Layer Sintering process (SLS)

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Technology and operation conceptLiquid resin solidification – StereolithographyPowder solidification – SinteringPolymer jettingFused depositionLaminated objects

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StereolithographyStereo – three dimensionsLithography – printingStarted with acrylic resins in the early 1980’sEpoxy resins are more common nowVery good accuracy $$$, Brittle (originally) UV Laser cure Relatively slow speedNewer resins with improved properties

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Supports structure

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Stereolithography apparatus - SLA

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UV Laser Depth of penetration

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Laser Laser

Bullet shape cure into resin, energy exposure determine the depth and width of cure pattern

UV laser cure into the resinBullet shape laser beam cure penetration into

resin

DpEc

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Laser cure on Epoxy resin

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Building on angle to min. supports

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SLA 5000 machine

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resins can get color by exposure

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Assembly part evaluation - SLA

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SLA parts can be metal plated

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Selective laser sintering -SLSDeveloped in late 1980’sPowder base $$$ good accuracyNo need for supports – powder is self supportingShrink and curl challenge Can do short run Rapid Manufacturing without

toolingRange of materials nylon to sintered metallic

powders

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Selective Laser Sintering - SLSSelective Laser Sintering - SLS

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SLS

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SLS Nylon parts

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Complex assembly – SLS model

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SLS Materials (partial list)

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Fused Deposition Modeling- FDMDeveloped by S. Scott Crump in the late 1980s Commercialized in early 1990sPrinciple of laying down molten material in layersNozzle is heated to melt the thermoplastics material The print head moves on X-Y Axis to draw the layerThe platform drops down on Z for each layerSeparate dissolvable support materialSeveral material and color options

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FDM

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Powder Liquid Binding

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inkjet-like printing head moves across a bed of powderselectively depositing a liquid binding materialA fresh layer of powder is added on top of the modelcan print parts in full color by the binding liquidunbound powder is removedlimited application in high accuracyPost cure by glue infilteration parts are fragile and brittle even after post processing The OEM of this Technology is Z-Corporation.

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Multijet; PolyJet Modelingwax-like thermopolymer plastic modelsPrinting head with multiple spray nozzles (jets)These jetting heads spray tiny droplets of melted material When cooled it hardens on impact to form the solid objectSome printers use UV cure processAccuracy depends on printer head resolution DPIGood for investment casting patterns

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MJM – Thermojet printer

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MJM

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MJM; PJM Printers

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MJM

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Object’s MJM printer

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Rapid prototyping categories Hi End: Above $100K

Mid Range: $40K – $80K

Low End: Below $20K

Competitive analysis

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RP Users

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Mechanical Properties for RPStrengthElongation / at brake / Elastomer ModulusToughnessHeat deflection temperatureIzod notched brakeHardnessClarity

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Mechanical Properties

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Mechanical Properties

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RP SequenceRP Sequence• CAD solid (surface) model

• “water tight” model• Tolerance

• ‘.STL’ file • Tessellation and file size

• Slicing the file• Final build data• Building (3D printing) the part• Supports removal • Post processing

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CAD Solid ModelCAD Solid Model• Solid model or closed surface model required

CAD to STLTo produce a model from CAD data, export 3D CAD

model as a STL file. The parameters used to generate this file will directly

influence the quality of the model. STL is the standard file type used by all Rapid

Prototyping systems. A STL is a triangulated approximation representation of

a 3D CAD surfaced model.You cannot build the model any better or smoother

than the STL. So if the STL is coarse and faceted, that's what you will see in the model.

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.STL File.STL File

• Software generates a tessellated object description

• File consists of the X, Y, Z coordinates of the three vertices of each surface triangle, with an index to describe the orientation of the surface normal

.stl – right hand rule - Normals

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stl with normal vectors

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Click for the movie

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.stl

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From Art to STL

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Physical parts can be scanned and output to STL format

triangle count of 20,024, file size of 1,001,284 bytes

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Watertight STL??

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“Bad” STL

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“bad” vs. “good” STL

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Slicing STL file

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STL Raw Slice Slice Layer data 3D part

Slicing the model –contour line

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Sliced contour

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Slicing STL data (.sli)

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Rapid Prototyping ApplicationsDesign evaluation

Physically holding a part vs. viewing it on screen

Function verification and testsForm; Fit; Function -- (FFF)Assemblies; wind tunnel; medical; marketing evaluation

Master patterns Casting; investment casting; soft tooling

Advance to production processJigs; prototype to metal

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RP in the Development CycleProduct design

Increase part complexity and diversity with little effect on lead time and cost

Minimise time-consuming discussion and evaluations of manufacturing possibilities

Tool design and manufacturingMinimise design, manufacturing and verification

of toolingReduce parts count and eliminate tool wear

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RP in Product Development Cycle

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Product designIncrease part complexity and diversity with little

effect on lead time and costMinimise time-consuming discussion and

evaluations of manufacturing possibilitiesTool design and manufacturing

Minimise design, manufacturing and verification of tooling

Reduce parts count and eliminate tool wear

RP in Product Development Cycle

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Assembly and testReduce labour content of manufacturing (e.g.

machining, casting, inspection and assembly, etc.)Reduce material costs (e.g. handling, waste,

transportation, spare and inventory, etc.)Function testing

Avoid design misinterpretations mistakes , i.e. what you design is what get)

From Prototyping to ToolingRapid tooling

Making the tool from the prototype masterSave time and money

Soft toolingFrom 3 to 25 parts per toolTools made out of Silicon Rubber (soft)plastic Polyurethane parts

Range of mechanical properties and colors

Wax parts for further Investment Casting

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Silicone RTV tool

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Saving time = Saving money

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RTV – Room Temperature Vulcanization Casting

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From Prototyping to ToolingBridge tooling

intermediary between Soft Tooling and Hard ToolingFrom hundreds to few thousands of partsback up materials like Epoxy Resin around the masterMetal powder interfiled toolsKeltool

Production tooling (NOT BY RP)Steel or aluminum machined toolsFor injection molding machinesMillions of parts from each tool

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Silicone tool casting

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Composite Tooling (Epoxy Tooling)molds are reasonably fast in comparison to machined molds relatively inexpensive way to create prototype and production tooling.much higher compression strength and heat resistanceGood when production material is requiredMaster pattern is by RP

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Bridge tooling (epoxy) and (wax)Part

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Rapid Tooling

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3D KeltoolModerate to high volume metal toolRP pattern from which a rubber mold is createdThe rubber mold is used to cast a steel powder and

polymer binder mixture – “green part”Copper infiltrated resulting in a tool with about 70%

steel and 30% copper contentAdvantageous for small, complex molds that would

require much time to make with CNC or EDM techniques.

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3D Keltool

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3D Keltool process

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Production (traditional) tooling

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Tool Cycle time – Tool Temperature

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