Full Analysis of Brake Pad Manufacturing Technology

English Translation

Brake pads are core components of automotive braking systems. Their sophisticated manufacturing processes directly determine braking performance, safety and service life. Modern brake pads mainly consist of three parts: steel back plate, adhesive thermal insulation layer and friction block. The production process includes ten core procedures, with varied technological priorities based on material types such as semi-metallic, organic and ceramic materials.

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1. Raw Material Preparation and Formula Design

Friction materials for brake pads are composite mixtures composed of 30 to 60 raw materials, categorized into four functional groups:

Category	Main Function	Typical Materials	Content Range
Binder	Bond components and enhance structural strength	Phenolic resin, cashew nut shell oil modified resin	5-25%
Reinforcing fiber	Form supporting framework and boost wear resistance	Steel fiber, glass fiber, aramid fiber, ceramic fiber	13-45%
Friction modifier	Stabilize friction coefficient and reduce noise	Graphite, antimony trisulfide, molybdenum disulfide	10-30%
Filler/Abrasive	Adjust density and optimize braking performance	Barite, calcium carbonate, alumina, silicon carbide	10-55%

Key Technical Points

Formulas are precisely designed according to vehicle types (passenger/commercial vehicles) and performance demands (comfort/high performance).

All raw materials undergo purity inspection and pre-treatment including drying and crushing.

Steel back plates are degreased, derusted and phosphated to improve adhesion.

2. Core Production Procedures

1. Powder Mixing

Two-stage mixing: Dry materials like fibers and fillers are mixed primarily, then binders are added for secondary blending.

Equipment: High-speed mixer, kneader or internal mixer to guarantee uniform material distribution.

Parameter control: Strictly regulate temperature to avoid premature resin curing, rotating speed and mixing duration. Mixing uniformity greatly affects brake pad quality.

2. Pre-forming (Optional)

Mixed friction materials are pressed under 4-9 MPa at room temperature into blanks close to finished shapes.

Functions: Reduce material loss during hot pressing, improve forming precision, ideal for irregularly shaped products.

3. Hot Press Forming (Core Process)

Preformed blanks or mixed powder are placed into molds together with treated steel plates, pressed at 150-180℃ and 25-30 MPa.

Double-layer pressing: Lay a roughly 3mm adhesive layer first, then the friction material layer for firm bonding.

Pressing time ranges from 30 to 120 seconds based on product thickness and formula to achieve preliminary resin curing.

4. Heat Treatment (Post-curing)

Hot-pressed brake pads are heated in curing furnaces at 180-220℃ for 2 to 8 hours.

Functions:

Fully cure resin cross-links to enhance strength and thermal stability.

Relieve internal stress and prevent deformation or cracking in service.

Improve high-temperature resistance and mitigate braking fade.

5. Grinding Processing

Surface grinding: Polish friction surfaces to specified thickness and roughness for tight fitting with brake discs.

Grooving and chamfering:

Grooving: Enhance heat dissipation, discharge brake dust and avoid thermal recession and noise.

Chamfering: Reduce braking squeal and protect brake discs.

6. Surface Treatment and Coating

Anti-rust treatment: Apply anti-rust paint or electrophoretic coating on back plates.

Marking printing: Stamp brand, model and production date.

Noise reduction piece installation: Attach nitrile rubber or metal damping sheets to cut braking noise.

7. Accessory Assembly

Fit wear sensors for certain vehicle models to remind users of pad replacement.

Install spring clips and positioning pins for convenient mounting and stable fixation.

8. Multi-stage Quality Inspection

Inspection Stage	Test Items	Standard Requirements
Raw material test	Composition, particle size, moisture content	Comply with formula standards
In-process test	Mixing uniformity, hot-pressing density, thickness	Tolerance ≤ ±0.1mm
Finished product test	Shear strength, friction coefficient, hardness, noise	Shear strength ≥10MPa, friction coefficient 0.35-0.45
Bench test	Braking performance, wear rate, thermal fade	Conform to GB5763-2018
Salt spray test	Corrosion resistance	No rust on back plates

3. Process Differences Among Brake Pad Types

Type	Process Features	Performance Advantages	Application Scenarios
Semi-metallic	30-70% metallic fiber, high hot-pressing temperature	High heat resistance, stable braking, long lifespan	Commercial vehicles, high-performance cars, heavy-duty vehicles
NAO Organic	Metal-free, mainly aramid and glass fiber, longer curing time	Low noise, less dust, harmless to brake discs	Passenger cars, comfort-oriented vehicles
Ceramic	Ceramic fiber and powder adopted, high grinding precision	Superior high-temperature stability, steady friction coefficient, nearly dust-free	Mid-to-high-end passenger cars, luxury vehicles
Powder metallurgy	Metal powder mixed with binders, sintering temperature up to 800℃	Extreme wear resistance, withstand temperature above 600℃	Racing cars, heavy machinery, high-speed trains

4. Critical Process Control Principles

Mixing uniformity: Monitored by online detection and sampling analysis to sustain stable friction coefficient.

Hot-pressing parameters: Precise control of temperature, pressure and time ensures consistent product quality, supported by automatic control systems in modern workshops.

Post-curing: Heating rate and holding time follow strict technological curves to avoid overheating or incomplete curing.

Grinding precision: Surface roughness Ra controlled within 1.6-3.2μm to secure initial fitting performance.

Environmental compliance: Restrict dust emission and recycle waste powder; copper content capped at 0.5% in regulated regions.