Additive Manufacturing Seminar This is NOT a sales seminar!!! My purpose here is to share information and educate

Introduction 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.

Rapid Prototyping (RP) Introduction of RP – Additive Process Generate a prototype part by Layering Manufacturing Technology - composite material layer by layer Build in one step - directly from model to manufacturing

From Concept to full Production

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.

Prototypes

Evolution of Rapid Prototyping 3D objects were used to demo model since early history Mud, wood, clay and paper was used to create mockups With 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 materials Advanced materials are leading into the future of rapid manufacturing techniques and technology

Evolution of Rapid prototyping 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 Prototyping In 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)

Technology and operation concept Liquid resin solidification – Stereolithography Powder solidification – Sintering Polymer jetting Fused deposition Laminated objects

Stereolithography Stereo – three dimensions Lithography – printing Started with acrylic resins in the early 1980’s Epoxy resins are more common now Very good accuracy $$$, Brittle (originally) UV Laser cure Relatively slow speed Newer resins with improved properties

Supports structure

Stereolithography apparatus - SLA

UV Laser Depth of penetration Bullet shape cure into resin, energy exposure determine the depth and width of cure pattern Laser Laser

UV laser cure into the resin Bullet shape laser beam cure penetration into resin Dp Ec

Laser cure on Epoxy resin

Building on angle to min. supports

SLA 5000 machine

resins can get color by exposure

Medical model visualization aid

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Assembly part evaluation - SLA

SLA parts can be metal plated

Selective laser sintering -SLS Developed in late 1980’s Powder base $$$ good accuracy No need for supports – powder is self supporting Shrink and curl challenge Can do short run Rapid Manufacturing without tooling Range of materials nylon to sintered metallic powders

Selective Laser Sintering - SLS

SLS

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SLS Nylon parts

Complex assembly – SLS model

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SLS Materials (partial list)

Fused Deposition Modeling- FDM Developed by S. Scott Crump in the late 1980s Commercialized in early 1990s Principle of laying down molten material in layers Nozzle is heated to melt the thermoplastics material The print head moves on X-Y Axis to draw the layer The platform drops down on Z for each layer Separate dissolvable support material Several material and color options

FDM

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Powder Liquid Binding inkjet-like printing head moves across a bed of powder selectively depositing a liquid binding material A fresh layer of powder is added on top of the model can print parts in full color by the binding liquid unbound powder is removed limited application in high accuracy Post 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 Modeling wax-like thermopolymer plastic models Printing 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 object Some printers use UV cure process Accuracy depends on printer head resolution DPI Good for investment casting patterns

MJM – Thermojet printer

MJM

MJM; PJM Printers

MJM Click

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Object’s MJM printer Click

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Rapid prototyping categories Hi End: Above $100K Mid Range: $40K – $80K Low End: Below $20K

Competitive analysis

RP Users

Mechanical Properties for RP Strength Elongation / at brake / Elastomer Modulus Toughness Heat deflection temperature Izod notched brake Hardness Clarity

Mechanical Properties

Mechanical Properties

RP Sequence CAD solid (surface) model ‘.STL’ file Slicing the file “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

CAD Solid Model Solid model or closed surface model required

CAD to STL To 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.

.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

stl with normal vectors

Click for the movie

.stl

From Art to STL Physical parts can be scanned and output to STL format triangle count of 20,024, file size of 1,001,284 bytes

Watertight STL??

“Bad” STL

“bad” vs. “good” STL

Slicing STL file STL Raw Slice Slice Layer data 3D part

Slicing the model –contour line

Sliced contour

Slicing STL data (.sli)

Rapid Prototyping Applications Design evaluation Physically holding a part vs. viewing it on screen Function verification and tests Form; Fit; Function -- (FFF) Assemblies; wind tunnel; medical; marketing evaluation Master patterns Casting; investment casting; soft tooling Advance to production process Jigs; prototype to metal

RP in the Development Cycle Product 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 manufacturing Minimise design, manufacturing and verification of tooling Reduce parts count and eliminate tool wear

RP in Product Development Cycle Product 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 manufacturing Minimise design, manufacturing and verification of tooling Reduce parts count and eliminate tool wear

RP in Product Development Cycle Assembly and test Reduce 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 Tooling Rapid tooling Making the tool from the prototype master Save time and money Soft tooling From 3 to 25 parts per tool Tools made out of Silicon Rubber (soft) plastic Polyurethane parts Range of mechanical properties and colors Wax parts for further Investment Casting

Silicone RTV tool

Saving time = Saving money

RTV – Room Temperature Vulcanization Casting

From Prototyping to Tooling Bridge tooling intermediary between Soft Tooling and Hard Tooling From hundreds to few thousands of parts back up materials like Epoxy Resin around the master Metal powder interfiled tools Keltool Production tooling (NOT BY RP) Steel or aluminum machined tools For injection molding machines Millions of parts from each tool

Silicone tool casting

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 resistance Good when production material is required Master pattern is by RP

Bridge tooling (epoxy) and (wax)Part

Rapid Tooling

3D Keltool Moderate to high volume metal tool RP pattern from which a rubber mold is created The 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 content Advantageous for small, complex molds that would require much time to make with CNC or EDM techniques.

3D Keltool

3D Keltool process

Production (traditional) tooling CORE CAVITY

Tool Cycle time – Tool Temperature

Thank you