q  This webinar will be available afterwards at www.designworldonline.com & email

q  Q&A at the end of the presentation q  Hashtag for this webinar: #DWwebinar

Before We Start

Meet your Speakers

MODERATOR FEATURED SPEAKER

Tony Holtz Technical Specialist Proto Labs

Leslie Langnau Managing Editor Design World

Prototype Smarter Transitioning to production faster and more effectively

Tony Holtz | Technical Specialist, Proto Labs

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§ What are you making? § What is its function? § What will be the material? § How many will you need? § What is your expected price?

Second

First

§  How do you want the parts manufactured?

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3D CAD Form + Fit Testing

Functional Testing

Low Volume

High Volume

Design for Production CAD allows us to design with production in mind

3D Printing CNC Machining Injection Molding

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3D Printing: Desktop vs. Industrial §  Desktop

§  Hobbyists or concept of design §  Fast and easy to use §  Poor surface finishes and small build frame §  Responsible for maintenance, scheduling and limited material

§  Industrial §  Applications range from prototypes to production parts §  Engineering-grade materials available

§  Thermoplastics, rubbers and metals §  High and micro-resolution possible §  Good surface finish; multi-colored and secondary finishing available §  Service bureau maintains maintenance, scheduling and material to avoid

downtime

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Direct Metal Laser Sintering (DMLS)

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Design Considerations for DMLS §  Support structures §  Overhangs §  Self-supporting angles §  Bridges §  Internal stress and warpage §  Channels and holes §  Internal features

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§  DMLS parts require supports to connect part to platform and hold features in place

§  Supports prevent part

from warping during rapid melting and cooling process

Support Requirements

Photo courtesy of Concept Laser.

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Support Removal

DESIGNTIP:Design parts that require minimal supports — this also improves part quality

§ Support Removal: machining, EDM, grinding and sawing

Photo courtesy of Concept Laser.

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§  Design large, flat, down-facing surfaces §  Work with manufacturer for proper part orientation §  If orientation is locked, create features that are

“self-supporting” §  Reduce hole diameters or create diamond- or tear

drop-shaped channels instead of round §  Minimize the amount of overhang — use proper

angles or decrease the gap between features

Minimizing Supports

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§  Unlike other additive processes, DMLS has a small allowance for unsupported overhangs (0.020 in./0.5mm)

§  If left unsupported, large overhangs may lead to build crash or deterioration of part detail

Overhangs

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CAD 50degrees 45degrees 40degrees

35degrees 30degrees 25degrees 20degrees

Self-Supporting Angles

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§  A bridge is any flat down-facing surface that is supported by 2 or more features

Bridges

§  Minimum allowable unsupported bridge distance is small (~0.080 in./2mm)

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§  Changes in cross-sectional areas can lead to warpage between features

Internal Stress and Warpage

DESIGN TIP: Use solid connections between sharp changes in cross-sectional area, and then remove with secondary operations

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§  Channels and holes are self-supporting features

§  Great for conformal cooling applications

Channels and Holes

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Channels and Holes §  As the hole diameter increases,

the overhangs increase near the closing of the hole

§  Unsupported holes larger than 0.31 in. (8mm) diameter will suffer downfacing distortion or curl, potentially creating other build issues

DESIGN TIP: Use diamond or tear drop shapes for larger diameter channels

Holediametersinmm

1512108654321

15mm(0.6in.) 12mm

(0.47in.)

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§  A huge benefit of DMLS is the ability to create complex internal features §  Channels, overhangs, self supporting angles and bridge dimensions must

all be taken into consideration when designing areas that may be hard to access

§  If an internal feature requires supports but allows no access, the supports remain inside, and the geometry may not function as intended

§  Accessibility for powder removal should also be taken into consideration DESIGN TIP: Lattice structures can be used internally to reduce weight and provide support

Internal Features

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Stereolithography (SL)

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Design Considerations for SL

§  Horizontal holes §  Overhang supports §  Sharp points §  Build orientation §  Support structures §  Holes §  Microfluidics §  Replacing metal with metal-plated SL

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Holes: § Ø 0.020 in. Normal Res § Ø 0.015 in. High Res § Ø 0.008 in. Micro Res

Channels: § 0.025 in. for High Res § 0.013 in. for Micro Res

Small Gaps: (negative spaces) § <0.025 in. can seal shut and

should be reviewed

Feature Recognition

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Horizontal Holes

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Overhang Supports

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Sharp Points Normal Resolution High Resolution

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Build Orientation

X-Direction (on its edge)

Y-Direction (flat)

Z-Direction (upright)

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Support Structures

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Hollow Parts

Hollow Model Section View Drain Hole Vent

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Microfluidics Sidewall surfaces will be moderately clear, but will have distortion from the layer lines. These surfaces are slightly more clear than downfacing, non-substrative surfaces. Typically upfacing surfaces will be the most clear

Downfacing surfaces that are not in contact with the substrate will be moderately cloudy due to the overcure on downfacing surfaces.

If built on a substrate, surfaces flush to the substrate will be comparably clear to upfacing.

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Stereolithography Compared to Injection-Molded PC

Accura 5530 Accura 60 Somos NanoTool PC (Molded) Hardness, Shore D 88 86 94 118-120 (R-Scale) Heat Deflection 338-482° F 127° F 185-437° F 250-280° F Tensile Strength 47-61 MPa 58-68 MPa 66-80 MPa 50-72 MPa Flexural Strength 96-108 MPa 87-101 MPa 103-149 MPa 82-93 MPa

Stereolithography Compared to Injection-Molded PP

Accura Xtreme White Somos 9120 PP (Molded) Hardness, Shore D 78-80 80-82 80-100 (R-Scale) Heat Deflection 117° F 126 - 142°F 124-203° F Tensile Strength 45-50 MPa 30 - 32 MPa 27-40 MPa Flexural Strength 75-79 MPa 44-46 MPa 41 MPa

Stereolithography Compared to Injection-Molded ABS

RenShape 7820 MicroFine Green Somos Watershed ABS (Molded) Hardness, Shore D 87 85 -- 109 (R-Scale) Heat Deflection 122° F 138° F 115-130°F 185-215° F Tensile Strength 39-51 MPa 45 MPa 47-54 MPa 32-42 MPa Flexural Strength 62-80 MPa 74 MPa 63-74 MPa 60-72 MPa

Know the Material Properties

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Replacing Metal with SLArmor Stereolithography compared to Die-cast Aluminum

SLArmor Die-cast Aluminum 10% metal volume 20% metal volume 30% metal volume

Heat Deflection 122-516° F >500° F Tensile Strength 100 MPa 145 MPa 200 MPa 300 MPa Elongation at Break 0.9% 1.04% 1% 2-5%

Mod. Of Elasticity 21,000 MPa 31,000 MPa 42,000 MPa 70,000 MPa

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CNC Machining § Processes for CNC machining include milling, turning,

routing, and lasers and plasma cutting § Wider range of materials versus 3D printing

§  Material properties comparable to injection molding § More established technology than 3D printing § Higher quantities and surprisingly faster

lead time over 3D printing § Challenges can occur with complex geometries,

endmill sizes and fixturing

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Injection Molding

§  You prototype with 3D printing and CNC machining, so why not with injection molding?

§  Low-volume injection molding provides actual molded thermoplastics the same way your production parts would be produced

§  25 to 10,000+ parts are typically possible from rapid aluminum tooling

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Design Considerations for Injection Molding

§  Material selection §  Wall thickness §  Coring out §  Draft §  Moldability §  Material flow

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Material Selection Characteristics to consider when selecting a material:

§  Chemical resistance §  UV concerns §  Temperature §  Flammability

§  Strength §  Stiffness §  Impact resistance §  Compatibility

Characteristics to consider during design process: §  Warp §  Sink §  Porosity §  Assembly

§  Material memory §  Appearance §  Tolerance §  Gate and ejection

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Material Selection Resin generic name Some brand names Strength Impact resistance High temperature Relative cost

Acetal Delrin, Celcon Medium Medium Medium-Low Medium

Nylon 6/6 Zytel Medium High Low Medium

Nylon 6/6, glass filled Zytel High Medium High Medium

Polypropylene Maxxam, Profax Low High Low Low

High Density Polyethylene (HDPE) Dow HDPE, Chevron HDPE Low High Low Low

Polycarbonate Lexan, Makrolon Medium High Medium High Medium High

Acrylonitrile Butadiene Styrene (ABS) Lustran, Cycolac Medium-Low High Low Low

Polycarbonate/ABS Alloy Cycoloy, Bayblend Medium High Medium Medium

Polybutylene Terephthalate Valox, Crastin Medium High Low Medium High

Polybutylene and Polyethylene Terephthalate, glass-filled Valox, Crastin, Rynite High Medium Medium Medium High

Polystyrene Styron Medium-Low Low Low Low

Thermoplastic Elastomer Isoplast, Santoprene Low High Low Medium-Low

Acrylic Plexiglas, Acrylite Medium Low Low Medium

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Wall Thickness by Resin Type

The table shows wall thickness that Proto Labs recommends according to resin. Please note that thin walls only work on small parts and thicker walls are required where the resin has a long way to flow. Proto Labs makes parts with dimensions of about 0.25 in. to 29.6 in. (6.3mm to 752mm).

Resin Inches ABS 0.045 – 0.140 Acetal 0.030 – 0.120Acrylic 0.025 – 0.500 Liquid crystal polymer 0.030 – 0.120 Long-fiber reinforced plastics 0.075 – 1.000 Nylon 0.030 – 0.115 Polycarbonate 0.40 – 0.150 Polyester 0.025 – 0.125 Polyethylene 0.030 – 0.200

Polyethylene sulfide 0.020 – 0.180

Polypropylene 0.025 – 0.150

Polystyrene 0.035 – 0.150

Polyurethane 0.080 – 0.750

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Uniform Wall Thickness As designed As molded

Sink

Warp

Cored

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Original Geometry Cored Geometry

Core out parts to eliminate thick walls

Coring Out Thick Area

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Core out parts to eliminate thick walls

You get the same functionality in a well-molded part.

Original Geometry Cored Geometry

Coring Out Thick Area

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Stamping, molding, casting, forming, machining — all benefit from draft

Undrafted Drafted

Draft

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Minimizes tool wear and flash with

telescoping shutoffs

Helps with part ejection

Draft

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Thermoplastic LSR / Elastomeric Metal Die Casting

Metal Sand Casting Machining 3D printing

1-3° 1-3° (hand removal)

3-5° minimum

5-7° minimum

0° possible (but not recommended)

0° possible (but not recommended)

Recommended Draft

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DFM Analysis for Molding

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Mold Flow Analysis

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Speed to Market

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Part Design §  What is its function? §  What are your preferred materials? §  How many parts do you need? §  What is your budget?

Questions?

MODERATOR FEATURED SPEAKER Tony Holtz Technical Specialist Proto Labs customerservice@protolabs.com @ProtoLabs

Leslie Langnau Managing Editor Design World llangnau@wtwhmedia.com @DW_3DPrinting

q  This webinar will be available at designworldonline.com & email

q  Tweet with hashtag #DWwebinar

q  Connect with Design World

q  Discuss this on EngineeringExchange.com

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