Dry press forming,is also known as compression molding.It is characterized by low binder content, only a few percent (generally 7% ~ 8%), it can be directly baked without drying, the shrinkage of billet is very small and can be automated production.

1.Process principle of dry pressing:

The essence of dry press forming is that the particles are close to each other in the mold under the action of external force.The internal friction force is formed on the periphery of the outer periphery of the particles.Micro pore pressure will pull the particles closer, that is, usually referred to as adhesion.

2.Way of Pressure and pressure distribution:

In the dry press forming, there are two kinds of pressurization: simple pressure and double pressure. Due to the different pressure, the pressure in the mold and powder friction, transmission and distribution are different, so the density of the billet is not the same.

3.Advantages and disadvantages of dry pressing method

Dry press forming is a commonly used method in the production of special ceramics, because it has the advantages of simple process, convenient operation, short cycle and high efficiency. In addition, the density of the green body is large, the size is accurate, the shrinkage is small, the mechanical strength is high, the electric performance is good.

But the dry pressing has difficulties of large billet production.first,the mold wear is serious and the machining is complex,and the cost is high.second,the pressure can only act on the upper and lower side ,the distribution of pressure is uneven,so it will cause uneven density ,uneven shrinkage, cracking, delamination phenomenon. With the development of modern molding method, this shortcoming is overcome by isostatic pressing.