What is the Advantage and Disadvantage of Automotive Felt Fabric

10 Mar.,2025

 

Advantages and disadvantages of common lightweight materials

Why to promote lightweight materials:

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1. Based on environmental considerations

Countries around the world are promoting policies to automobile manufacturers to reduce automobile fuel consumption. Some research data show that the car car weight reduction of 10%, fuel consumption increased by 6% -8% car overall weight per 100 kg, 100 kg fuel consumption reduction of 0.3-0.6 liters, CO2 emissions reduced by about 5g/km. It can be seen that the car's lightweight and the improvement of fuel economy, fuel economy, and even environmental protection and energy saving is closely related to the improvement of fuel economy, fuel economy, and even environmental protection and energy saving. Therefore, automobile lightweight has become the consensus of automobile enterprises.

2. Pressing the transformation of automobile manufacturing technology

If you can't ensure driving safety, no matter how light and fuel-efficient the car is, no one dares to drive. If the pursuit of absolute safety and collision resistance, can only drive dozens of tons of tanks, to withstand hundreds of liters of fuel consumption per hour. Therefore, lightweight is the trend of automobile manufacturing, and the current lightweight is mainly to reduce the self-weight of the car. Although the body, as the main carrier of the car, needs to ensure sufficient rigidity, strength and fatigue durability performance, so that the whole car has good safety, vibration noise and durability performance, but lightweighting puts forward higher requirements for these factors, undoubtedly, the transformation of automobile manufacturing technology has brought about a great stimulus.

Achieve the basic principles of automotive lightweight materials:

1. Ensuring sufficient rigidity

Rigidity refers to the ability of the material to deform to external forces, usually refers to the elastic properties of the body development especially before the material yields. Good stiffness is the basis for the NVH performance of the vehicle, vehicle dynamics and fatigue durability performance, and common evaluation indexes are the torsional stiffness of the body and so on. Stiffness is related to the modulus of elasticity of the material. Basically, the type of material is determined, and the modulus of elasticity is also determined. For example, the rigidity of a body will not increase even if high-strength steel is used. This is because all steels have the same modulus of elasticity.

2. Ensure adequate strength.

Strength refers to the ability of a part to maintain its function after yielding to an impact load, and is commonly used in the evaluation of body crash safety, impact resistance, and other properties. Strength is related to the yield strength and fracture strength of the material, in order to improve the safety performance of the car, the modern body design of high-strength steel is mostly used for this reason.

3. Maintain good fatigue durability performance.

Fatigue durability performance refers to the ability of components to maintain function after long-term exposure to alternating loads, the reliability and durability of the car is evaluated accordingly. Fatigue durability properties are related to the fatigue curve of the material, and of course, the fatigue properties of welded joints and other connections on the car are more important. Third, the method of realizing automobile lightweighting:

4. Optimize the car sound structure and improve the material utilization.

SAE Felt: What is it and how is it made? - BIT Felt

Home > Resources > SAE Felt: What is it and how is it made?

SAE Felt: What is it and how is it made?

What is SAE Industrial Felt?

SAE industrial felt, or technical felt, is nonwoven wool felt used in technical applications. There are two methods of manufacturing industrial felt: wet felting or dry needle punch felting.

Technical felts are produced in a variety of thicknesses, densities, and compositions to meet a wide range of needs. The SAE, formerly known as the Society of Automotive Engineers, mandates the standards of measurements applied to nonwoven wool felts used in:

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  • Gaskets
  • Dryer seals
  • Pads
  • Washers
  • Vibration Cushioning
  • Dust Shields
  • Acoustic Panels

At Bouckaert, we custom manufacture our SAE industrial felt using the needle punch method. Before discussing the differences between manufacturing methods, here are the characteristics of SAE felts and nonwoven wool felts in general.

Characteristics of Industrial Wool Felt

Felt is a versatile fabric explicitly engineered for high-pressure applications in specialized industries. With the natural benefits of using wool fiber (click here for our previous post on wool felt usages), here are some of the advantages to using industrial wool felt:

  • Maintains its physical properties as it wears
  • Highly absorbent and moisture-wicking (will seal out lubricants and oil)
  • Sound and vibration dampening
  • Does not ravel or fray
  • Resistant to wear and tear
  • Acts as a filtration system (gas and oil applications)
  • Excellent padding for moving parts in machinery
  • Natural fire-retardant properties

Industrial applications such as these require high levels of aversion to abrasion, oil and grease absorption, and wear and tear. To ensure the best application results, SAE felts are classified by their density, wool content, and durability.

  • Density: Each grade of SAE felt ranges from hardest to most pliable, the main differing characteristic between felt grades. The thickness of pressed wool felt is controlled by the amount of pressure or needling applied during the manufacturing process. The denser the felt, the better it will retain its shape against the physical environment.
  • Wool content: Each grade of SAE felt is (usually) a combination of raw wool fibers and polyester fiber but additional materials such as cotton, rayon/viscose, synthetic, or plant fibers can be used instead. These 'filler' materials are added to create a particular characteristic to the final product that can not be achieved by wool and/or polyester alone.
  • Durability: During the manufacturing process, the more pressure/needling applied (we will get into this in the next segment), the denser the felt will be. Durability relies, in part, on the amount of densification.

To note, the color of SAE industrial felts will vary. Since the wool used is natural and undyed, there is no way to control color consistency from lot to lot. There are also strict tolerance requirements based on wool content and density combined. The shape of wool can change naturally (depending on temperature) or manually (from cutting the material); density and wool content need to be adjusted to consider tolerance issues.

The Differences in Manufacturing

Wet Felting VS Dry Needle Punch Felting

All technical felts are produced under the same specs; the difference lies in the manufacturing process. Despite these 'technical' differences, both processes in making SAE grade felt start the same way.

The wool fiber is first cleaned and blended with any additional synthetic materials before the carding process. The carding machine disentangles and mixes the fibers together to create a uniform web, aligning the individual fibers into a singular direction. Several of these webs are layered in alternating directions on a machine called a cross-lapper to build-up to the weight of the desired finished felt. This layered material will be much thicker (and less dense) than the finished product as it has not been densified yet. This material is referred to as a batt.

Wet Felting

The wet felting manufacturing process is known as the more 'traditional' way of producing nonwoven felts. It uses heat, moisture, and pressure to mat and densify the fiber together.

The batts are wetted with hot water and fed into a plate hardener. The plate hardener applies vibrational pressure to the wetted material using rollers to help the fibers interlock together. The hot water, added acid, and pressure eventually cause the batts to shrink down in size, creating the densely matted fibers of a pressed felt.

The wet felt is left with a sulfuric acid residue that is then neutralized in tanks filled with sodium chloride (soda ash) and warm water solution. Once the felt is neutralized, it goes through a refulling machine to smooth out any irregularities on the surface. The felt must then be dried either in a dryer or oven or hung and stretched in a drying room.

Needle Punch Method (Dry Needle Felting)

Here at BIT, we manufacture our SAE grade felts using the needle punch method. Needle punched SAE felt is marked with an 'N' for 'needled in the official designation (example F-7N).  Here's the difference in manufacturing:

As the name suggests, dry needle punch felting eliminates the use of moisture. Instead, the batts enter a needle loom; a precise machine that uses thousands of barbed needles mounted on a needle board to pierce the layered webs of fiber. The repeated punching of the needles entangles the fibers together to create the thick, dense felt.

Depending on the desired density, some needle punched SAE felts will then go through a heated press to further densify the material. Read more in-depth on the needle punch method here.

So Why Use Needle Punched Felt Vs A Pressed Felt for your SAE Needs?

The Pros and Cons of Needle Punched SAE Felt Vs Pressed SAE Felt

The use of chemicals in wet pressed felts gives the advantage of creating a smoother finish that allows the material to hold its shape better as it wears. The upside for needle punched felt is its economical and eco-friendly benefits; eliminating the use of harsh elements makes a cleaner production line that is more cost and time effective.

For exceptional sound insulation, needle punched felt is the go-to choice for acoustic paneling needs. But if there is one thing to remember when choosing between a wet felt or a needle punch felt, it is that both are produced under the same specs mandated by the SAE. The performance of needle punch felt is not compromised because of its manufacturing process.

Want to know how BIT can add value to your business by providing custom manufactured SAE grade industrial felts? Get in touch today!

If you want to learn more, please visit our website Automotive Felt Fabric.