Trends in plastic optics manufacturing enable customers to include plastic optics into designs with reduced costs and more versatility. These trends involve advances in computer-aided design (CAD), computer-aided machining (CAM), metrology software and instrumentation, single-point diamond turning (SPDT) and polymer materials, and optical process engineering.
When customers need a plastic optical component for a system design, SPDT manufacturing processes address needs at the earliest stages of the project. Prototyping can be completed simultaneously as a plastic injection mold design and construction, allowing optical samples to hit the lab in as little as a month.
About SPDT and Polymer Materials
Direct diamond turning works for various polymers, including COP, styrene, acrylic, and polyetherimide.
Polycarbonate materials aren’t appropriate for diamond turning because they are soft. Because of this, customers should always discuss the project’s needs with the supplier in advance to determine the best materials to create optics.
Polymer molding materials may include:
- Acrylics: Polymethyl methacrylate (PMMA) acrylics offer advantages like high strength, low weight, exceptional mechanical properties, and enhanced optical clarity for sight gauges, light fixtures, medical devices, and lenses.
- Polyetherimide: Polyetherimide (PEI) is an amorphous thermoplastic that offers improved thermal, optical, mechanical, and electrical properties. PEI is suitable for high-temperature applications in automotive, electrical, medical, and industrial applications.
- Polystyrene: Polystyrene is a rigid and transparent thermoplastic that molds easily and offers exceptional processing stability, light transmission, and radiation stability for diagnostic medical optics.
- Polycarbonate: Polycarbonate (PC) is a strong plastic that’s more durable than other polymers, with improved transparency and impact resistance. PC’s light-transmission properties are nearly comparable to glass, making it ideal for medical devices, automotive components, and lighting fixtures.
SPDT and polymer materials have many advantages, including:
- Speed of delivery
- Sophisticated surface profiles
- Lower tooling costs
Customers can deliver high-precision samples for system testing with a reduced lead time with SPDT and polymer materials. Diamond turned plastic prototypes also require less tooling in fabrication than injection molding, reducing the recurring costs and manufacturing lead times.
One of the most significant advantages of SPDT and polymer is accuracy. Tight control of surface finishes is possible thanks to accurate and precise turning equipment. Additionally, designing complex surface geometries directly into the polymer optic, such as CAD Freeform surfaces and off-axis aspheric surfaces, is possible.
Manufacturing Process
Not all polymer materials are easy to fabricate, so there are two primary manufacturing processes:
- Molding: Molding is a common method to mass-produce polymer materials in larger quantities. This method makes it relatively quick to produce plastic elements after construction of the mold. The inserts used in the injection mold are produced via SPDT, with its inherent high accuracy.
- SPDT: SPDT1 reduces the lead times of fabrication, allowing designers to test materials and designs relatively quickly. Not all materials are suitable for SPDT, however. PMMA, COC, COP, and polystyrene are appropriate for SPDT.
Applications of Polymer Materials
As technology demands smaller and lighter products, the viable solution lies in polymer optics. Projects traditionally using glass optics required machined aluminum, steel, or brass components to assemble, but some of those features (e.g., flanges) can be included in the plastic lens design.2 This opens possibilities for reducing the total components (optical plus mechanical) required for a system.
Polymer materials have numerous applications that go far beyond replacing glass components with polymer components. These materials can offer new solutions to existing problems, such as producing one-time-use products, eliminating the need for sterilization between reuses.
Here are some examples of polymer applications:
- Biometrics: Polymer materials marry design versatility with repeatability and low costs for retinal scanning, facial imaging, and fingerprint detection.
- Biomedicine: The production of polymer materials is cost-effective for single uses, such as disposable surgical treatment devices and blood diagnostics.
- Defense systems: Plastic components are lightweight and low cost, making them ideal for defense solutions like head-up displays, tracking devices, and guided weapons.
- Illumination: Polymer is perfect for illumination systems due to its light weight and high transmission.
About Apollo Optical
Apollo Optical specializes in SPDT and injection molding of polymer optics in production and prototype volumes. Our company is a world leader in optical system design, engineering, and precision polymer optics. We provide innovative optical solutions for consumer, commercial, medical, automotive, and LED light markets. Contact us today to discuss your custom optical component or assembly!
Sources:
- https://www.photonics.com/EDU/Handbook.aspx?AID=25504
- https://spie.org/Publications/Book/796330?SSO=1
