“Helmet Safe Shell Production: Part 4”

Motorcyclists & Motorsport enthusiasts, buckle up for a compelling journey that unveils the crucial link between helmet safety and your passion for adrenaline. We shed light on the specific risks you face, and the devastating consequences of Traumatic Brain Injuries (TBIs), & present an innovative solution to fortify your protection.

Welcome to The Helmet Doctors, where we strive to empower you with the knowledge and tools to ensure a safe and exhilarating ride/drive every time knowing your helmet’s structural integrity is in optimal condition.

Below and the following stories we will brief you on the areas:

• The Hidden Dangers,
• The Unseen Perils of TBIs & Death,
• How to Empower Prevention through Preventative Measures & Helmet Laser Scanning,
• The Simplicity of Taking Action to Enhance Your Safety,
• How you can become a Beacon of Hope for others,
• How Joining our Passion for Advancements in Helmet Safety Can Save Lives and How It Just Might Be Yours That Counts.

But now let’s look at …

Manufacturing Of Motorcycle Helmets – 

The Inner Shell: PP, PE & Pb Foam Liners

Polypropylene (PP), Polyethylene (PE), and Polybutylene (Pb) foam liners

Similar to the EPS foam liner, a conventional mold with a core and a cavity is used for the PP, PE, and Pb foam liners. The core and the cavity are typically hemispherical in shape but extend beyond 180° of curvature to provide an undercut in the helmet. 

Due to the resilient nature of these foams, the undercut region of the helmet will bend to allow the helmet to be removed from the mold at the end of the process without causing any liner distortion (Shuaeib et al. 2002b). Retention system attachment holes and ventilation holes are also able to be molded into the liners at the same time. Figure 4 on our website shows projections corresponding to the holes for ventilation and helmet chin straps in the rear of the helmet are configured on the cavity part of the mold and the holes for ventilation and helmet chin straps in the front of the helmet are configured on the core part of the mold (Gessalin 1984). 

These projections are usually located perpendicular to the surface of the helmet and hence the minimum amount of helmet material is removed to accommodate the holes. This set-up of projections also allows the liner enough elasticity to be removed from the mold without fracturing. The advantages and disadvantages of manufacturing PP, PE, and Pb foam liners for motorcycle helmets are outlined and better viewed in Table 4 on our website and are also listed below. 

Advantages

1. Excellent impact performance, close to that of EPS and PP liner helmets
2. Most of the EPS manufacturing constraints are eliminated by using this method

Disadvantages

1. PE liners have good impact performance but are comparatively heavier than EPS
2. PE cannot be recycled for any re-use of the foam (Mills 1993)
3. PP liner helmets have reduced compression strength at high temperatures (Mlyajlma and Kitahara 1999)

For more content or illustrations, head to our website, or check out our FAQ. To reference our article to your friends, or family, in the Motorcycling/Motorsport community, click the link below or simply copy this URL or bookmark the page for future referencing: https://thehelmetdoctors.com/contact-us-helmet-protection-motorcycle-safety-course/. Otherwise read our next article about Manufacturing Of Motorcycle Helmets – The Inner Shell: EPS Liner, titled “Helmet Shell Manufacturing: Part 3”

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