6 Design Considerations for Polymer Optics

Posted by Aimee Schenck on Dec 23, 2016 11:00:00 AM

Quality. Quantity. Cost. In precision manufacturing, the consensus is that you can improve two out of three. You can’t get “more stuff that works better but costs less.”

Recent leaps in precision manufacturing have changed that equation in the field of polymer optics. You really can get you higher volumes at lower cost without sacrificing performance. To get all of those advantages, though, you have to keep a few special factors in mind. Here are the top six:

1. Talk to your optical manufacturer before you get too far into your optical design.

Early communication with the manufacturer is good advice for any optical designer, but for polymer optics it is critical. Polymer optics have unique features, and the selection of polymer materials and the associated manufacturing capabilities advance quickly. The only way to take full advantage of the latest technology is to talk to an expert who is knowledgeable about recent advances in optical polymers and molding methods. 

2. Anticipate your production needs.

Production rate will usually determine the method of fabrication. Single-point diamond turning (SPDT) is a good choice for low production rates; injection molding is the way to go for large volumes. The selection of fabrication method will determine your range of materials and your manufacturing tolerances, both critical factors when designing optical systems.

3. Be mindful of unique design concerns.

Polymer optic materials and fabrication methods introduce factors that may not be relevant to glass optics. Specifically, part dimensions, stress and strain coefficients, and thermal conduction are all important factors when working with polymer optics. Injection molded parts usually have a small seam where the mold halves meet. Your design process needs to include analysis of those factors.

4. Take advantage of the unique benefits of polymers.

The idiosyncrasies of polymer optics can be advantageous. For example, injection molded optics provide the opportunity for adding non-optical features to the optical elements. For example, a polymer optical element mold could include labels, alignment markers, mounting fixtures, etc.  It is also often possible to use a polymer’s heat sensitivity to counter thermal issues in the overall optical system.

5. Clean up your design.

You’re not ordering from a catalog! Injection molded parts entail custom-made tooling and molds. If you discover a simpler design later, you can’t just change your order or your specifications.

6. Make your optical design intelligible to non-optics people.

As stated in point 5, custom injection molded optical elements require special tooling. The specifications for fabricating a metal part will be different than the those for the optical part. It is critical that the dimensions and tolerances of the optical design are not in “optical-ese.” If a mechanical engineer interprets a dimension differently than you intended, you may end up with a very precise mold of the wrong part.

Remembering these six points helps us give you the best optics at the best price and ensures that your polymer optics meet your precision needs – higher quality and quantity, lower cost and weight.

If you have any questions about our polymer optics designs or would like to speak to our team, please contact us.

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Topics: Engineering & Design, Molded Optics