Ceramic dry pressing machines are key equipment for producing ceramics by dry pressing. The process loads ceramic powder into a mold and applies pressure, causing powder particles to move closer together and bond through internal friction, forming a green body with a certain shape. During dry pressing, pore size and pore count in the green body decrease significantly, density increases notably, and the body gains a certain strength. Dry pressing performance is affected by many factors, including powder properties, pressing method, pressure, and holding time.
1. What Is a Ceramic Dry Pressing Machine?
A ceramic dry pressing machine is mechanical equipment that uses the dry pressing method to form ceramics. Powder is first granulated with a small amount of binder, then filled into a mold. Under the force of the press, the powder particles approach and bond to form a green body. Common dry pressing methods include single-action, double-action, and four-direction pressing, as well as improved techniques such as vibration and magnetic field pressing.
2. What Is the Dry Pressing Principle?
The dry pressing machine fills powder into a metal mold and presses it into shape. Powder containing 5%–8% moisture is loaded into the mold, and force is applied to compress it. During this process, gas is expelled, particles displace and pack closely, and a green body with the same cross-section as the mold is finally formed. This process significantly reduces pore size and quantity, while increasing density and green body strength.
3. Factors Affecting Dry Pressing Performance
Powder properties: These include bulk density, flowability, particle size distribution, and moisture content. They directly affect dry pressing performance.
Pressing method: Pressure loss caused by internal and external friction may lead to uneven density in single-action pressing. Double-action or staged pressing can reduce this phenomenon.
Pressing pressure: Within a certain range, increasing pressure helps improve density, but excessive pressure may cause lamination cracks or mold damage. For structural ceramics, a pressure of 70–100 MPa is usually suitable.
Holding time: Sufficient holding time helps internal pressure transmission and gas expulsion, ensuring uniform density distribution.
For ceramic forming equipment builders and mold maintenance teams, Hansheng Automation can machine non-standard parts from customer drawings, such as pressing punches, mold sleeves, guide blocks, and fixture plates, in single pieces or small batches.
