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Prototyping of Optical Parts for Cars Is Important: Here is Why and How

In this article, you’ll learn why the prototyping of optical parts for cars is important and how you can do it.

Prototyping of Optical Parts

Automotive development is a challenging task. Even in the seemingly secondary area, the lighting of the car poses serious challenges to designers and manufacturers. The reason for that is a combination of factors: production cycles (between models) are getting shorter and geometries and styles are getting more and more complex.

Prototyping of Optical Parts for Cars

While designers work in the relative stability of their CAD systems, prototyping companies struggle to meet deadlines for the complex and yet high precision components to test, certify, and optimize. The most complex job in car lighting is the creation of clear optical prototypes.

What Types of Clear Parts Can Be Used for Car Creation

The automotive industry nowadays uses plastics for clear parts. They are more durable, lightweight, and cheap. However, not every type of clear part is useful for automotive design purposes.

Plastic parts usually have grades of clarity: Optically clear (when you can see through the part and not notice anything), clear (it looks like the previous one but is more cloudy), and translucent (simply doesn’t block light completely).

Automotive developers only use optically clear parts because they offer the best aesthetics and functionality (maximum light brightness).

Why Clear Optical Part Creation is Important Right Now

Statistics suggest that the car optics market is growing at a stable pace. It’s been growing at about a billion USD a year. However, company owners predict that the demand for clear optical parts will grow rapidly. Why is that? Because of the autonomous pilot systems development going in strides.

An auto-pilot car doesn’t only need lighting but a considerable number of cameras and optical sensors. Integrating every one of them into the car design will require a significant addition of the clear optical parts to prototype and mass produce. That will boost the market.

Which Automotive Elements Require Optical Clear Parts

We’ve already mentioned some of the car components that need to have clear optical parts. But let’s list them again to have the whole list.

So, these automotive prototypes need clear optical parts:

  • Headlight Prototype Lenses
  • Back Light Prototype Lenses
  • Light Guide (Pipe) Prototypes for Car Lighting systems
  • Interior Lighting Lens Prototypes
  • Clear Optical Enclosures to Estimate Prototype Efficiency at Proof-of-Concept Stage (for example, the air flowing through the manifold)

When Can Clear Optical Prototype Parts Be Useful In the Automotive Industry

What is the purpose of creating clear optical prototypes?

They can be useful in a number of stages of either the whole auto development or in the modification of the existing cars.

The first step is proving the concept idea. At this stage, you simply make the prototype to make sure that the light is transmitted the way you want it to (especially useful for complex lighting systems with light pipes and led tapes).

Prototyping of Optical Parts for Cars

The next stage you may require those parts is design verification. You need to assemble the whole lighting system made of the specified materials to make sure it can be assembled and there are no impossible features. And the most important stage has to deal with certifications and tests.

The lights must be IP certified and pass a lot of safety tests. All of that requires quite a number of perfectly clear plastic parts. And we haven’t mentioned Customization

Creating Custom Headlight Prototypes for Car Customization and New Design

Using clear optical prototyping of plastic parts for car customization is a convenient and easy way to get high-quality unique lighting systems for your automobile in short order. A lot of car enthusiasts employ prototype manufacturing services for that. But in order to make a good custom light, you’ll need to know a few details

What will you need to have?

You’ll need either the existing lighting system or its precise dimensions or at least its 3D-data ( model or a 3D-scan). From that information, a new design can be developed. It would be great if you had specific requirements or sketches.

Which Parts do You need to create?

The major parts of lighting systems include a clear optical lens, a deflector, and a number of light guides if you want a complex design.

Cost estimation of the Customization. Always ask about the costs beforehand because such customization may be costly.

Choosing the Best Materials for Optical Prototypes

Currently, optical prototypes are manufactured from three types of plastics: PC, ABS, or PMMA.

The first one is the strongest but is it very hard to process. So, it is mainly used for the later stages of prototyping in order to run tests or verify the design.

ABS and PMMA are much easier to machine, cast or process in any other way so they are used for proofs-of-concept or in cases where certification or strength tests are not needed ( for example for interior lights or custom designs)

The Four Main Clear Optical Part Manufacturing Processes

Clear optical Prototype Manufacturers employ 4 basic manufacturing processes to create automotive lighting parts. These are 3D-printing, Vacuum casting, injection molding, and custom CNC machining.

All of these processes have their own specifics but ultimately they provide high-quality freeform transparent parts. Note, I wrote transparent, not optically clear. In order to make them perfect, you’ll need another step: surface finishing.

This process is the one that makes them so hard to make and so expensive. All of the above require special equipment and skills. True, you can print something with PMMA on your 3D-printer but it won’t even be close to a professional thing.

Design Limitations of Clear Parts And How You Can Overcome them

Naturally, you can’t make anything you’ve imagined. Even the 3D-printers who can create any shape are limited by their printing zone. CNC machines can’t reach some deep or thin pockets and casting has problems with overhangs.

One way to overcome that is to make an assembled lens. Split it into simpler elements and then glue them together. If your manufacturer offers such a solution, don’t doubt it. Chosen wisely and processed and glued correctly, the joints won’t be visible.

Achieving Optical Clearance for Optical Prototypes

The hardest operation to create car light parts is making them optically clear. There is a number of ways to reach this condition. For plastics such as ABS or PMMA, a chemical method of polishing has become popular.

By submerging the part in an acetone (or similar) mist, you can greatly increase the purity of parts. But it won’t be perfect and some materials like PC are not chemically active. So, you’ll need to hand polish the parts. It’s a long and complex manufacturing process but yields perfect results.


Making prototypes for car lighting systems is a very important task especially with the rise of new automotive vehicles and mass customization being the trend of the decade.

It is a complex job that involves a number of rapid prototyping and machining operations and it should be left to the professionals if you want your prototype or custom light systems to look good or perform well in tests.

That’s it thanks for reading. If you have any questions about this topic you can ask in the comments. Subscribe to our newsletter to get notification of new engineering articles.

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About Saif M

Saif M. is a Mechanical Engineer by profession. He completed his engineering studies in 2014 and is currently working in a large firm as Mechanical Engineer. He is also an author and editor at www.theengineerspost.com

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