Optical lighting plays significant roles in various aspects of manufacturing, from automotive and electronics to the medical industry. Before now, glasses were the go-to material for fabricating optical devices. However, in recent times various prototype manufacturing companies are switching to plastics for designing clear optical prototypes.

Besides being a relatively cheaper alternative, plastics are highly versatile, allowing manufacturers to fabricate more complex and sophisticated optical devices. In addition, plastics have better durability and are suitable for common manufacturing techniques, such as injection molding and prototype machining. Therefore, fabricating large volumes of clear optical prototypes is achievable quickly, maintaining impeccable part consistency. 

When dealing with the fabrication of optics, especially from plastic polymers, injection molding comes to mind; however, CNC machining is also suitable. Let’s take a more detailed look at the processes and steps involved in producing and prototyping optic devices.

Designing Optical Prototypes from Plastics

As mentioned earlier, suitable methods for manufacturing plastic optics include injection molding and machining. Generally, the injection molding technique is ideal for manufacturing almost any object made of plastic, including small and large-volume production. That said, it is the go-to technique used in manufacturing optical parts. 

However, CNC machining techniques are the go-to for prototyping clear optical prototypes. This results from the better dimensional accuracy it provides the prototype, among other benefits. The processes may include drilling, milling, contouring, etc., depending on the design complexity of the desired optical lighting parts. For components with intricate details, you may utilize multi-axis machines to ensure high precision and dimensional accuracy. 

Generally, milling operations play crucial roles in manufacturing optic devices, like lens mounts and automotive lighting, among other optical parts. It allows fabricating of intricate details and complex geometries in optic components from viable plastics. Therefore, once you’ve created your design, you configure the machines to work on suitable materials – mainly reflective plastics with suitable optical properties. 

With milling, there’s little to no material wastage with impeccable material. The rotatory cutters meticulously reduce size to shape the plastic polymers until the desired shape is achieved. In fact, using multi-axis machines, such as the five-axis machine allows you to make cuts across different axis of the block of material. This feature is beneficial for manufacturing parts with complex features yet maintaining high precision.

Machining or injection molding techniques create high-quality optical parts that adhere to strict design requirements. However, CNC machining is preferred when the focus is to design clear prototypes or essentially small-scale production. This could be attributed to some of its advantages over injection molding. To mention a few, optical prototype machining is faster and more suitable for more advanced design complexities.

Once, you have your prototyping clear parts, the next thing is to verify that the manufactured prototype meets all the design requirements. This includes a group of testing and analysis, such as dimensional inspection, optical and environmental testing, etc. In addition, you will need to observe for manufacturing defects, like burning, burring, or the presence of tool marks. Specific assessments relating to optical gear involve assessing the light transmission, scattering, and other essential optical features, depending on your prototype. 

Also, post-processing operations may prove effective for enhancing the quality of your parts. These operations include a series of finishing options which include coating, polishing and anti-reflective treatments. The focus of these operation encompasses refining your fabrication’s surface quality and enhancing its optical activity. Improving the optical performance involves reducing its light scattering property while increasing transmission and reducing undesirable reflections. The result is clear optical prototypes with enhanced appearance and aesthetics, including improved mechanical and chemical resistance.

Considerations For Fabricating Plastic Optical Devices 

Before fabricating any component, including plastic optics, you must adhere to some design specifications.  Let’s take a brief overview of each. 

Optical Design 

The first thing to consider is to factor crucial optical properties into your optical design. This includes the focal length, aperture, field of view, and other optical parameters. You may also need to manage chromatic aberration and minimize light scattering and reflection to ensure optimum optical features. To do this, you may use multiple lens designed from optically active materials with known refractive indices. Also, lens coatings may assist in managing light transmission.

This may seem difficult when designing the optical devices yourself. However, working with a service may help ease things. Just ensure that your CAD files contain all your design requirements. In addition, you should use suitable optical design software and simulation tools, like Zeemax, CODE V, light tools, etc. They help ensure proper design optimization and that your fabrication meets all design requirements, resulting in top-notch clear optical prototypes. 

Material Selection

We have emphasized that the focus is to create plastic optics, not glass or composites. That said, not all plastics are suitable for optics. Consequently, you need to ensure that you select an optical-grade plastic. This ensures that it fits the intended use. 

The most used plastic for optics is acrylic which possesses top-notch optical properties, such as optical clarity, refractive index, transparency, light transmission, etc. In addition, they have high thermal stability, mechanical strength, and environmental resistance. Other suitable plastics for plastic optics include polycarbonate, polystyrene, and polyethylene terephthalate (PET). Each material has specific properties. For example, polycarbonate has superb impact resistance, and polystyrene for components that require low ultraviolet transmissivity. 

Besides being highly durable, one main feature that makes plastic highly suitable for designing optical prototypes is its inertness and biocompatibility. Also, they are safer to use. In the case of a shatter, plastic devices cause relatively zero harm, especially to humans, compared to glass. This feature makes them highly beneficial to the medical sector, where they are used to create optical components that come in close contact with humans, such as the eye.

Conclusion

Plastic is an excellent material of choice for fabricating optics. Indeed, it is more cost-effective than glass; it is also more resilient, with little to no damage upon shattering. In addition, upon combining glass and plastic polymers in fabricating a product, optical features of the latter can be integrated into the final fabrication. 

At Wayken, we specialize in using CNC machining, injection molding, and other relatable manufacturing techniques to produce plastic optical devices. Contact us for your manufacturing needs if you need automotive light components or medical optical lighting features.