1. Custom Prototyping for Lighting Applications
How to use rapid injection molding and 3D printing
for housings, fixtures and optical parts
Tony Holtz | Technical Specialist, Proto Labs

2. Do you currently use rapid manufacturing during product development of custom optical and lighting prototypes?

3. Additive manufacturing (3D printing) and injection molding provide quick-turn parts for several industries Learn how you can leverage these services during development, and bring products to market faster and more cost effectively.

4. Low-volume Injection Molding
25 to 10,000+ parts in 1 to 15 days
SPI-A2 quality clear parts
Great for lens, light pipe, housings and all injection-molded prototypes and low-volume production parts
Hundreds of clear, transparent and opaque thermoplastic materials available
Thermally conductive materials available for lighting housings to dissipate heat

5. Thermoplastic MaterialsPC
Lexan and Makrolon
Improved impact resistance over PMMA
Up to 89% transmittance
PMMA (Acrylic)
Can improve part quality in thick parts over PC
Up to 92% transmittance
K-Resin
Improved flexibility over PC and ABS; can be used in a living hinge part design
Fills well in thin parts
Up to 93% transmittance
Styron
Medical and packaging industries
High tensile strength
Up to 90% transmittance

6. Thermally Conductive Plastic
Do you need heat dissipation? Plastics can:
Reduce weight up to 50% over other materials
Lower cost of manufacturing over die casting
and machining
Improve features with traditional injection molding techniques
Reduce assembly costs with part consolidation
Improve thermal conductivity by times over conventional plastics
Can reach 35+W/(m.k) compared to 167+W/(m.k) for aluminum, so please do your homework
Used extensively in LED luminaire, electronics and aerospace industries
Applications like automotive cooling systems, battery/motor housings and sensors
Materials like CoolPoly and Therma-Tech are just two examples of advanced materials that are making an impact in the industries.

7. Design Considerations: Plastics
Ejection
Will ejector pins be on a cosmetic surface or are alternative ejection possible?
Gating
Is your gate on a cosmetic surface and how will the knit lines effect your cosmetics?
Part thickness
Will your part have sink or voids in thick areas?
Undercuts
Undercuts can be achieved, but some may not be possible
Surface finish
Does your part need to be clear, textured a combination?
Draft
Surfaces that are highly cosmetic may require more draft for improved mold release

8. Liquid Silicone Rubber (LSR) Molding
25 to 5,000+ parts in 1 to 15 days
Up to 94% light transmission
Extreme thin and thick parts
Improved light pipes, LED and outdoor lighting designs
Lightweight, flexible, non-yellowing, vibration control,
scratch, crack, UV and heat resistant
Up to 400% flexibility
-49 to 392°F (-45 to 200°C)
Easily cleaned and chemical resistant
No ejection required and minimal gate vestige

9. Material Selection: LSR
Clear
Elastosil 3003 (30,50 and 70 durometer)
Most commonly used
Water Clear
Dow Corning QP1-250 (50 durometer)
Medical devices or components, USP class VI
Optically Clear
Dow Corning MS-1002 (70 durometer)
Primary or secondary lenses,
light pipes and light guides

10. Design Considerations: LSR
Are you able to combine parts to minimize assembly?
Does your part require a gasket? An LSR lens can eliminate multiple components
You don’t have the typical molding constraints that you do for PC or acrylic
Mold your part with thick and thin walls
Mold your part using negative draft
Mold your part using no ejection or concern
of where the gate would be located
Mold your part with minimized knit lines,
sink and voids
Surface finish
Does your part need to be clear,
textured or a combination?

11. Design Considerations: LSR.

12. Design Considerations: LSR

13. Side-by-Side Comparison
Silicone PC
PMMA
Glass
Light Transmission
94%
88-90%
93%
95%
Refractive Index
1.42
1.58
1.49
1.52
UV Resistance
High
Low
Medium
Chemical Resistance
Temperature
>150°C
120°C
90°C
>200°C
Yellowing No
Yes
Micro Detail
Thick Part
Yes >1 in.
>PC
Minimum Part Thickness
<0.020 in.
0.040 in. -

14. 3D Printing: Stereolithography (SL)
1 to 50+ parts in 1 to 7 days
Nearly any geometry possible
Small complex parts
Thick cross-sectioned parts
Post processing for optically finished part
Hand polish and sprayed with clear coat
Near distortion-free appearance similar to molding
High clarity and transparent materials or finishes available
Not truly optical — some level of distortion is possible and should be considered
Produce multiple parts together
Custom finishes allow multiple colors or finishes on each part

15. Material Selection: Clear SL
Somos WaterShed XC (ABS)
Ideal for lens applications in high-humidity applications
3D Systems Accura 60 (10% GF PC)
Clear with blue tint and high stiffness
Accura 5530

16. Design Considerations: SL
Avoid thin ribs or internal cavities that would be difficult to polish
Part orientation for build — where would support structures be located?
Is your surface completely flat? If so, can a substrate such as an acrylic sheet be used? This helps on flat surfaces, but internal surfaces may still be hazy

17. Design Considerations: SL

18. Manufacturing Processes at Proto Labs

19. Benefits of using Proto Labs
Reduced up-front investment
Increased speed to market
Design for manufacturability (DFM) analysis is built into quote
Talk with on-hand experts regarding design and process
Quick return time on quotes
Instantaneous for additive manufacturing
Within hours for machining and molding

20. Interactive Quote for Molding

21. Complete DFM Analysis for Molding

22. Mold Flow Analysis for Molding

23. Do you think a custom prototype manufacturer can help during product development? Upload a 3D CAD model online at protolabs.com for an interactive quote with free design and cost analysis.

24. Questions? Tony Holtz | Technical Specialist, Proto Labsor