Chopped Graphite Paper has found its way into the production of brake shoes, playing a significant role in enhancing the performance of brake shoes friction materials when integrated into brake shoes mixtures and mixes.

Chopped Graphite Paper is renowned for its remarkable thermal conductivity, which can reach up to 500 – 800 W/(m·K) in high – quality variants. This property is crucial for brake shoes as it enables efficient heat dissipation during the braking process. In a high – speed braking experiment, when the temperature at the friction surface of a traditional brake shoe without chopped graphite paper soared to 500°C within 30 seconds, the brake shoe with 10% chopped graphite paper by weight managed to keep the temperature below 350°C under the same braking conditions. This shows that the high – thermal – conductivity chopped graphite paper can effectively transfer heat away from the critical friction area.

It also possesses excellent electrical conductivity, with a resistivity typically in the range of 10 – 5 – 10 – 4 ohm – meter. This characteristic can be utilized in modern braking systems to prevent the build – up of static electricity, which might otherwise interfere with the operation of electronic components in the vehicle.

Although the chopped graphite paper itself has a relatively low tensile strength in isolation, when incorporated into the brake shoes mixture, it can enhance the overall mechanical strength of the brake shoes friction material. For example, adding 5% chopped graphite paper to the brake shoes mixture can increase the tensile strength of the friction material by approximately 15 – 20%, from around 10 MPa to 11.5 – 12 MPa.

One of the most significant advantages of using chopped graphite paper in brake shoes is its exceptional heat – dissipation ability. Brake fade, which is a reduction in braking performance due to overheating, is a major concern in high – performance braking. Tests have demonstrated that brake shoes with chopped graphite paper can maintain a stable friction coefficient of 0.4 – 0.45 during continuous high – speed braking for 5 minutes, while traditional brake shoes without it experienced a sharp drop in the friction coefficient to 0.2 – 0.25 within 2 minutes. This stable friction coefficient ensures reliable braking performance even under extreme conditions.

Graphite has natural self – lubricating properties. When chopped graphite paper is added to the brake shoes friction materials, it can significantly reduce the wear between the brake shoes and the brake disc. In a long – term wear test with 500,000 braking cycles, the wear volume of the brake shoes with chopped graphite paper was only 2 – 3 cm³, while that of the non – graphite – containing brake shoes was 6 – 8 cm³. This represents a 50 – 60% reduction in wear, which not only extends the service life of the brake shoes but also reduces the frequency of brake disc replacement.

Chopped graphite paper helps in maintaining a more consistent friction coefficient across different operating temperatures. In a temperature – cycling test from 25°C to 400°C, the friction coefficient of brake shoes with chopped graphite paper varied within a narrow range of ±0.03, while the friction coefficient of the reference brake shoes without it fluctuated by ±0.1. This stable friction coefficient is crucial for providing a smooth and predictable braking experience for the driver.

The production of high – quality chopped graphite paper involves complex manufacturing processes, which results in a relatively high cost. Incorporating chopped graphite paper into brake shoes can increase the production cost by 50 – 70% compared to traditional friction materials. This cost increase may limit its application in price – sensitive mass – market brake shoes.

Ensuring uniform dispersion of chopped graphite paper in the brake shoes mixture is a challenging task. Uneven dispersion can lead to inconsistent performance of the brake shoes. For instance, if the graphite paper is concentrated in certain areas of the brake shoes, those areas may experience excessive heat dissipation and reduced friction, while other areas may have insufficient heat dissipation and increased wear.

Chopped graphite paper can be affected by environmental factors such as moisture and chemicals. In a humid environment with a relative humidity of over 80%, the performance of the brake shoes with chopped graphite paper may degrade. The friction coefficient can drop by 10 – 15% due to the absorption of moisture by the graphite, which may compromise the braking performance.

In conclusion, chopped graphite paper offers numerous advantages in terms of heat dissipation, wear reduction, and friction consistency in brake shoes production. However, its high cost, processing difficulties, and sensitivity to environmental conditions pose challenges that need to be addressed. Brake shoe manufacturers need to carefully balance these factors based on the specific requirements of their products and the market they target.