How It’s Made: Bicycle Helmets

Vladimir Pick
Apr 25, 2017 · 8 min read

A photo and video story of how bike helmets are manufactured

In 2016, our team visited several bike helmet factories in China and learned about how they’re made. Photos and Videos from two different factories are featured in this article, both of which we visited in person in 2016.

The Design Process

Tens of millions of bike helmets are made in China every year and making bike helmets is a relatively simple, but exact process. New designs are often sketched first, then modeled either by hand in real clay or using CAD software and milled in prototyping foam. These prototypes are tested for fit and looks.

Most bike helmets follow this basic construction pattern and have these three main components:

  1. A hard outer shell to keep everything together
  2. A compressible inner liner to absorb energy during a crash
  3. Assorted straps and pads to keep the helmet on your head safely and comfortably

The Hard Shell

There are several ways to create helmet shells, and choosing one depends on the material and construction of the final product. Here’s a PolyCarbonate (PC) shell being made from a blank sheet on a Vacuum Forming machine.

The vacuum forming machine uses a custom-designed tool shaped like the inside of a helmet to form the shell. The blank sheet of PC is heated, then vacuumed tightly over the vacuum tool to get its final shape.

Larger factories can make their own tooling on site by milling it from solid blocks of steel, aluminum, or sometimes other materials. Each completed tool ends up being about the size of a mini-fridge.

Other times, shells are made in more common plastic Injection Moulding machines — the same kind that probably made your toothbrush or phone case. Thicker ABS shells for skate-style helmets are often made this way.


Shell Painting and Decals

Next, some of the shells are painted. The painting process is a mix of automated spray-painting robots and humans doing the loading/unloading with humans applying the finishing touches.

Some shells have more intricate designs that are applied on the raw material sheets before they are formed. These designs appear warped when they are flat but become proportionally-correct after they are shaped into a helmet shell.

In other cases, brand logos are pad-printed or silk-screened onto new helmets.


The Inner Liner

Helmet liners are designed to take a hit for you. Their lightweight aerated construction makes them able to absorb a lot of energy during an impact, protecting your head.

Liners are most commonly made from Expanded PolyStyrene, or EPS. Yes, this is the same stuff your new TV came packed in. Although more helmets are made with Expanded PolyUrethane (EPU) and other chemically-expanding foams, EPS remains the standard because it’s safe, reliable, and cheap.

EPS liners are made with high-pressure steam in specialized machines and tooling.

PolyStyrene pellets arrive at the factory loose, in oversized bags, and are treated with high-pressure steam at temperatures up to 200° Celsius until they expand to fill a mould that bonds them together and shapes them into a solid helmet liner. Designers vary the thickness and density of the EPS to account for the helmet’s shape and vents.


Straps and Pads

Straps are often sourced from a nearby specialized strap manufacturer and assembled on-site.

The nylon strap factory was down the road from the helmet factory. The specialization of sub-suppliers in industrial China is a good reminder that we live in a networked economy and the future of manufacturing is distributed.

Straps arrive at the factory in bundles, pre-stitched and with the buckles already in place.

The inner comfort liner is often custom-pressed and cut on site. These pads start off as layers of cloth and foam that are pressed and melted together with a template on a machine — similar to a table-sized George Foreman Grill making foam and cloth panini.


Robotics and automation

Like any modern factory, helmet factories employ a number of robots to do simple, precise, repetitive tasks. After all, China is now the world’s leader in both production and consumption of industrial robotics.

Although modern factories employ automation everywhere, humans and robots often collaborate in the same spaces. Robotics companies are encouraging this growing paradigm by designing industrial robots as co-bots, or collaborative robots, like Baxter.

Safety and Quality

Of course all helmets are rigorously tested for a variety of head-sizes. The International Standards Organization (ISO) does not care if it’s stereotyping, so it assigns common head-shapes to various regions around the world. For instance, helmets designed for Asian markets must be wider and shorter front-to-back, while helmets designed for the US market are narrower and longer front-to-back. This all ensures that the most people get the best fit possible with only a limited number of helmet sizes.

Before approving a design for mass production, all new helmets must pass strictly enforced national and international standards. These tests involve crashing weights at high speeds into helmets to simulate impacts, cycling through extreme temperatures and humidity, and durability tests on components like straps and buckles.

All units are inspected by hand and tested for a sturdy construction, and even cosmetic imperfections are caught. The damaged units are either repaired or recycled before being packaged to leave the factory.

Packing

This machine makes boxes automatically. The bosses said it does the job of six workers at once.

Despite the occasional box-making machines, helmets are most often packed and finished by hand by workers in assembly lines. For the manufacturing nerds reading this, all helmet factory assembly lines we saw were U-shaped.

Perhaps the most interesting experience while visiting a helmet factory is walking along buildings the size of a football field filled with thousands and thousands of helmets in various stages of production.


Shipping

Ultimately, most helmets end up in a standard shipping container like this one outside our factory gate. They spend anywhere between 25 and 45 days in transit before they reach their final destination.

If you’re new to global logistics, it’s easy to overlook that containers are a fascinating invention that moved our society forward by leaps and bounds. Here’s a great podcast about refrigerated containers, their immense contribution to the global supply chain, and the woman that made them possible.


Picking out Prototypes

Using everything we learned, we picked out our favorite go-anywhere all-city commuter helmet. We chose our design to have open venting to keep your head cool on fast summer rides, but it’s cut to fit over a cap for those harsh winter commutes.

This helmet is made in one of the factories you saw in this article, adhering to the highest international safety standards. We worked to make it safe, lightweight, but sturdy enough to get knocked around strapped to your bag or your bike.

Before it can be a Fortified product, we’re going to put it through its paces: we made 20 sample units, shipped them to our office, and for the coming months they’re going to be tested on the road. Do you have feedback or ideas about your ideal commuter helmet? Get in touch.


Vlad is the COO of Fortified Bicycle. This post was reviewed to not reveal any confidential or proprietary information about the production processes employed by the companies featured in this article. Rights to the products pictured in this article belong to their respective manufacturing or trading companies.

Vladimir Pick

Written by

COO @fortifiedbike in BOS. Interests include: organizations, connected hardware, manufacturing.