Tail Light Lens: Functions, Materials and Manufacturing Process

Many people consider the car headlight the most beautiful and aesthetic-focused part of a car. Is this true? Well, it is a matter of perspective, as those who hold the previous view will not argue about the uniqueness of the car tail light lens.

The car tail light lens and cover are made to be structurally good while being aesthetically pleasing. As a result, businesses that want to venture into aftermarket production need to understand the auto part and a quality-focused design/manufacturing process, all of which are discussed in this article.

painting tail lighting partWhat is a Tail Light Lens?

A tail light lens is one of the important plastic auto parts located at a car’s rear, and it functions in protecting the light bulb, improving optical properties, etc. It has a characteristic red color (although this is customizable), coatings, and other modifications to achieve specific light patterns depending on the car’s design.

The tail light lens material composition makes it strong, impact-resistant, and weatherproof. As a result, they can function in different environmental conditions. Furthermore, they are in two categories: OEM and Aftermarket. The OEM lens comes directly from the manufacturer, they are quality but costly. However, aftermarket lenses are less costly but have uneven quality.

Functions of Tail Light Lenses and Covers

Like the headlight lens, the tail light lens provides several functions that aid in the tail light functions during the driving process. These include:

Protect the Light Bulb

The primary function of the tail light lens is to protect the light bulb from the external environment. This comes in the form of UV protection, impact resistance, and weather scaling since car tail lights are exposed to different environmental elements that can alter the bulb or other internal components’ functionality.

Diffusion and Dispersion

Another function of the tail light lens is to disperse and diffuse the emitted light. This is important in maintaining a uniform illumination pattern and preventing concentrated light spots. The enhanced visibility ensures that you can communicate with other drivers effectively, and the tail light is noticeable to other drivers.

Depending on the model, tail lights come with different sections with different filters for different purposes. For example, red filters are for brake lights, and white/clear for the reverse light. As a result, it is possible to match the color filter with the intended function.

What Kind of Plastic Materials Used in Tail Light Lens?

The kind of plastic materials for the tail light lens and tail light lens cover depends on the manufacturer’s choice, the specific design, and technical requirements. Common materials used for the tail light lens include:

pc materialPolycarbonates (PC)

Polycarbonate is a lightweight tail light lens material known for its durability and stability due to its high impact resistance and UV stability. Furthermore, its optical clarity, even after exposure to several environmental elements, makes it an effective material for making lenses with uniform light diffusion.

pmma car prototypePoly Methyl Methacrylate (PMMA)

Acrylic is the most common tail light lens material due to its transparency, optical clarity, and UV resistance. Furthermore, its lightweight and moldability makes it a suitable material for making lens with uniform illumination and enhanced visibility.

Manufacturing Process for Tail Light Lenses

The tail light lens requires high attention to detail and precision to meet automotive regulations and specific design requirements. This section talks about the key aspects from material selection to the manufacturing process.

Material Selection

The right tail light lens material will influence the lens’s mechanical and optical properties. Hence, manufacturers need to consider the properties such as impact resistance, transparency, UV stability, and heat resistance. Furthermore, the material choice should comply with the legal and safety regulations and requirements for vehicle lighting components and have aesthetic qualities such as color, texture, and finish that can sway the market regarding the tail light lens.

The tail light lens is also compatible with custom headlight manufacturing processes such as:

CNC Machining Process

CNC machining is a manufacturing process used for prototyping the tail light lens. The process includes techniques such as CNC turning, milling, and drilling and involves using a computer-controlled tool to remove part of the workpiece to form the finished product.

Furthermore, the CNC lens parts can be used as a master mold for vacuum casting. In the CNC machining process, a sharp tool is important especially if the tail light lens material is acrylic, as it prevents the plastic from deformity, which affects its optical clarity.


  • It is a highly precise prototyping process;
  • Compatible with complex tail light designs;
  • It is compatible with several plastic materials.


  • It is a more expensive process unless outsourced to a manufacturing service.

Vacuum Casting

Vacuum casting or vacuum forming is another manufacturing process for making tail light lenses. The process involves creating a mold using CNC machining or 3D printing and drawing molten material into a mold using a vacuum. Due to the vacuuming process, this produces parts of high quality when the molten material solidifies into a final product.

In addition, the vacuum casting process is suitable for low-volume tail light lens production and creates a precise replication of the prototype’s details.


  • Produces high-quality parts;
  • Suitable for low-volume production;
  • Low cost;
  • Dimensionally accurate;
  • A high degree of flexibility.


  • Shrinkage may occur in parts that are too thin or thick;
  • Not suitable for mass production;
  • Quality can be affected by the mold.

Injection Molding

Injection molding is a manufacturing process that involves injecting molten plastic into a predesigned mold. On cooling the plastic solidifies, takes the shape of the mold, and is ejected. Injection molding is highly popular in the mass production of tail lights and other auto parts, such as the headlight lens.


  • Suitable for mass production of plastic parts;
  • It has a minimal cost of labor;
  • High material compatibility;
  • Low material wastage.


  • Unsuitable for large-size parts;
  • High set-up cost;
  • Prone to defects such as warping, jetting, and weld lines.

clear tail light lensSurface Treatment for Tail Light Lens

The manufactured tail light lens will also undergo a surface finishing treatment for better appearance or function. Common surface finishing options employed include:


Deburring as a surface treatment option requires a visual inspection of the lens and identification of sharp edges or burrs on the part. Afterward, a tool (deburring tool) is used to remove the edges present so the part becomes smoother and safer to handle.

Vapor Polishing

Vapor polishing is another common surface treatment to improve optical that involves exposing the tail light lens to a chemical vapor. This causes the surface to flow, thereby improving optical clarity and smoothness.

Hand High Polishing

This surface treatment involves skilled artisans using manual tools, abrasive substances, and polishing compounds to achieve an optical surface on a tail light lens. While it improves the optical clarity and quality of the auto part, hand-high polishing is more expensive and time-consuming due to the manual processes and machines involved.

Quality Control for Custom Tail Light Lenses

After completing the manufacturing process, the light lenses also undergo several quality control measures to ensure that they meet the design specifications, safety standards, and other parameters.

Defect Inspection

There is a thorough inspection of the lens to identify any defects or imperfections like air bubbles, inclusions, or structural flaws. This is critical as it can affect the part’s structural capabilities or aesthetic value.

Dimensional Accuracy

Another quality control measure is to ensure the lens is dimensionally accurate. This will eliminate improper fitting during the assembly process.

Optical Properties

The quality control process also checks the lens’s optical properties, including transparency and the ability to diffuse and transmit light.

Environmental Testing

Tests that can show the durability of the part in different environments, such as impact tests and UV radiation tests, should be done to validate the lens’s ability to withstand use in different environments.

Installing the Tail Light Lens

After passing the quality control, you can install the tail light lens. The installation process should ensure a secure fit of the auto part and allow it to function as required. Furthermore, the process should protect the integrity of the light bulb without affecting other automotive exterior lighting components.

taillight lensPractice Tips When Making a Custom Tail Light Lens

The design and manufacturing process for tail light lenses requires acute engineering expertise in the material and manufacturing process available. The following tips and practices can help in a successful manufacturing process.

Choose the Right Material

The lens’s aesthetic value and functional ability depend on the choice of material. Hence, choosing the right material is critical. Before choosing one, you should consider properties such as transparency, impact resistance, UV stability, and heat resistance.

Furthermore, some materials require the use of the right cutting tools. For example, with acrylic, machining must be done with a very sharp tool to prevent the material from deformity, affecting its optical clarity.

Ensure Optical Functions

Manually check the tail light lens for optical functions such as diffusion of light and transparency. Furthermore, check for imperfections that can compromise the optical function of the tail lens.

Test the Product

Subject the finished products to test to show their functionality and aesthetics in different environments. This will allow you to guarantee their intended performance in such conditions.

Design Trends in Tail Light Lens

There are several advancements in technology related to the car tail light lens. Below are a few design trends that businesses should take note of.

  • Sleeky But Minimal Designs: Tail lights are becoming sleeker and minimal, making the car tail light lens smaller. As a result, modern vehicles are more streamlined, improving their aerodynamics. Furthermore, the size reduction also means a lower cost of production.
  • Full-width Tail Light: While some cars have a sleeky and minimal design, some utilize a full-width tail light with better aesthetics. Furthermore, the light is more visible, which makes it safer.
  • LED Tail Light: They are more efficient and longer lasting than traditional incandescent bulbs. Furthermore, they are flexible in design and allow a complex and dynamic light pattern. Aside from that, it ensures you can focus more on materials with aesthetic value due to lesser heat generation by the LED light.
  • Dynamic Tail Lights: Dynamic taillights use sequential lights to create a more noticeable and eye-catching signal. This trend is especially popular for turn signals and brake lights.
  • Laser Tail Lights: Laser taillights are currently the latest tail light technology, which uses lasers to create ultra-thin and bright light lines. They are new and are increasingly popular on high-end vehicles.

Let AutoProtoWay Handle Your Car Lens Projects

Custom manufacturing tail light lenses is a delicate task and it is best left to the experts. At AutoProtoWay, we are a partner committed to your success. Our experienced teams work closely with you from the initial concept to the final product, offering machining services and solutions to ensure that your custom tail light lenses meet your requirements.

With one-stop manufacturing capabilities, including CNC machining, vacuum casting, rapid injection molding, and surface finishing, you can confidently take the car projects to us. At WayKen, we also understand the importance of quality and lead time, we take 100% inspection for each part to ensure high-quality production and delivery of each tail light on time. Just get a free quote today to start your new projects!


The tail light lens is a unique car part that should be structurally good and aesthetically pleasing. This article aims to help businesses that want to venture into aftermarket production by introducing the automotive part and the different design/manufacturing processes you can use.


How are tail light lens molds created in manufacturing?

The most common manufacturing processes for the tail light lens molds are CNC machining and 3D printing. The better method depends on the material, precision, and design complexity.

What is the difference between a headlight and a taillight?

Headlight differs from taillight based on their location and function. The headlight is located at the car front and helps a driver to see the road at night. On the other hand, taillights are at the car’s rear, and help the driver indicate a change in signal or application of the brakes to other drivers.

What material is the most common for making car tail light lenses?

The most common car tail light lens material is acrylic due to its durability and optical properties.

Hi, click here to send us a message. 欢迎随时与我们联系~