How to ensure the thickness uniformity and surface flatness of semi-metallic brake pads during the production process?

1. Material preparation stage
(1) Raw material particle size control
The particle size distribution of the raw materials (such as metal powder, friction modifier and reinforcing fiber) of semi-metallic brake pads directly affects the density and surface quality after pressing.
Solution:
Use screening equipment to strictly grade the raw materials to ensure consistent particle size distribution.
Control the particle size range to avoid particles that are too large or too small affecting the pressing effect.
(2) Mixing uniformity
If the mixing is not uniform, it will cause local component differences, which will affect the thickness uniformity and surface flatness after pressing.
Solution:
Use a high-precision mixer (such as a twin-screw mixer) to ensure that all ingredients are fully mixed.
Take samples regularly during the mixing process to verify the mixing uniformity.

2. Pressing process
(1) Pressure distribution control
Uneven pressure distribution during pressing may lead to inconsistent thickness and uneven surface.
Solution:
Use a multi-point pressure sensor to monitor the pressure distribution of the pressing mold in real time.
Adjust the mold design to ensure that the pressure is evenly applied to the entire friction material.
(2) Pressing temperature control
Temperature that is too high or too low will affect the curing effect of the binder, and thus affect the density and surface quality of the pressed part.
Solution:
Set the appropriate pressing temperature according to the formula requirements and use a temperature control system to keep it constant.
Calibrate the heating equipment regularly to ensure temperature consistency.
(3) Mold accuracy
The design and manufacturing accuracy of the mold directly affect the shape and size of the pressed part.
Solution:
Use high-precision CNC machine tools to process the mold to ensure that the mold surface is smooth and the size is accurate.
Regularly check and maintain the mold to prevent dimensional deviation due to wear or deformation.

3. Sintering process
(1) Sintering temperature and time
Improper control of sintering temperature and time may lead to uneven internal structure of the material, affecting the thickness and surface quality of the final product.
Solution:
Establish strict sintering process parameters (such as heating rate, holding time and cooling rate), and use a program-controlled temperature sintering furnace.
Regularly test the density and hardness of the sintered product and adjust the process parameters to optimize the results.
(2) Sintering atmosphere
The sintering atmosphere (such as air, nitrogen or vacuum) may affect the chemical stability and surface quality of the material.
Solution:
Select a suitable sintering atmosphere according to the formulation requirements.
Use a gas flow controller to accurately control the atmosphere conditions.

4. Post-processing process
(1) Grinding
Grinding is the last step to ensure the thickness uniformity and surface flatness of the brake pad.
Solution:
Use a high-precision grinder equipped with an automatic thickness detection device.
Set reasonable grinding parameters (such as feed speed, grinding wheel speed) to avoid surface damage caused by excessive grinding.
(2) Surface roughness control
Surface roughness directly affects the friction performance and noise performance of the brake pad.
Solution:
Use a roughness measuring instrument to detect the surface after grinding.
Adjust the grinding process according to the test results to ensure that the surface roughness meets the design requirements.

5. Quality inspection and control
(1) Online inspection
Set up automated inspection equipment on the production line to monitor thickness and surface flatness in real time.
Solution:
Use a laser thickness gauge or ultrasonic detector to measure the thickness of each brake pad.
Equip a visual inspection system to identify surface defects (such as cracks, pits or scratches).
(2) Random inspection and data analysis
Take samples regularly for detailed inspection and analyze the data to find potential problems.
Solution:
Use statistical process control (SPC) tools to analyze production data and adjust process parameters in a timely manner.
Record and analyze the causes of non-conforming products and optimize production processes.

6. Application of advanced technologies
(1) Digital manufacturing
Introducing digital manufacturing technology can improve the controllability and accuracy of the production process.
Solution:
Use industrial robots to complete key processes such as mixing, pressing and grinding.
Combined with Internet of Things (IoT) technology, real-time collection and analysis of production data.
(2) Laser processing
Laser processing technology can achieve high-precision surface treatment and edge trimming.
Solution:
Use laser cutting or laser marking equipment to fine-tune brake pads.
Reduce stress concentration and surface damage caused by traditional mechanical processing.