Automotive Sealing Technologies: Advanced Body Seals

Compression molding automotive door seals

The automotive manufacturing world has changed drastically over the past 10 years.  Manufacturers are looking towards increasing their automation processes and improving their line’s efficiency.  With so many new names entering the market, now is the time to starting upping your manufacturing game.

In this post, we're going to explore how tier-1 automotive manufacturers that use rubber door seals are making the shift towards more complex parts as a way of meeting (or even exceeding) OEM's strict criteria, while also optimizing their manufacturing line's efficiency.

Compression Molding Body Seals vs. Extruding

One of the trends becoming more widely looked into and accepted is compression molded body seals for curved surfaces instead of standard extruded seals. Before we get into why the automotive market is beginning to make this shift, let's first get a better understanding of the two different processes:

Compression Molding is a forming process where an uncured rubber compound is loaded into an open, heated mold cavity, in which then the heated mold halves are closed and pressure is applied to force the material to fill the mold's cavities in order to conform to the shape of the mold.  

Extruding on the other hand is a part forming process in which a high-pressure extrusion machine forces rubber material through a shaped die in order to get it to take on its section profile. Extruded seals have been the industry standard for a long time due to lower costs, but with more complex requirements and testing from OEMs, these types of body seals won't be able to always get the job done.

So, why choose compression molding over extruding?  

One of the main factors would be compression molding's ability to produce large, complex parts. By compression molding, you're able to add intricate geometrical features. Extruded seals also don't have any curve or arch shape molded into their final form, which may cause them to crease up during installation. This makes installing more difficult and may impact your ability to meet specs.

rubber molded door sealrubber molded door seal

By compression molding the seal, you can add intricate features AND mold the curve into the final product. The image shows an example of what this might look like with your application.

While these types of seals provide better sealing and NVH qualities, the drawback to compression molding is the higher price point. Because of this, you may need to find ways to offset those costs with more highly engineered advanced seals.

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Advanced Compression Molded Body Seals

Sure, moving to a compression molded seal with intricate geometry can be a major improvement, but why stop there?  Let’s take it a few steps further.

Design-for-Assembly (DFA)

First, let’s think about Design for Assembly (DFA). How can you make your assembly line’s job easier and more efficient? A few things you’re going to want your supplier to think about and implement includes:

  • Adding an industrial adhesive strip to help stabilize the seal on the door throughout the assembly process and product life
  • Knowing the correct adhesive to use – Acrylic Adhesive’s bond becomes stronger over time while other adhesives (like silicone) will weaken overtime
  • Using an appropriate liner to protect the adhesive against dirt, dust, and moisture before installation
  • Packaging of the seals will be vital in order to maintain the quality of the seals and avoid issues with the adhesive liner coming undone

Consolidating Suppliers

Next, let’s look at it from a sourcing perspective. If your rubber seal includes some sort of plastic fastener, why not look into consolidating suppliers? You’re now able to do that AND have the fasteners pre-installed with the seals before it reaches your assembly line.

Material Selection

Door seals will be exposed to a variety of different elements. Selecting the right material will be vital to pass testing an receive approval from an OEM.  Because of this, in order to take your part to the next level, you’ll want to partner with a supplier that knows rubber materials well. You’ll need a compounded rubber that delivers the required mechanical and acoustic properties needed. 


Adding new technology and increasing fuel efficiency are not the only aspects of a vehicle OEMs are investing in to improve their newest models.  Compression molding arched door seals rather than sticking with extruded versions is one of the many new advances in automotive manufacturing.  If you’d like to learn more about Echo’s capabilities and our core technologies, contact us, and we’ll have one of our representatives reach out to you as soon as possible.

Connect with our team of pros!

We'd love to help you solve your company's biggest production challenges.

Let us know what project you're working on and how our team can help you create the best solution!

Connect with our team of pros!

We'd love to help you solve your company's biggest production challenges.

Let us know what project you're working on and how our team can help you create the best solution!

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