The processing process of powder metallurgy is powder preparation (batching and mixing) -- pressing molding -- sintering -- post-treatment.
This process is described in detail below.
1, the preparation of powder involves the preparation of materials: according to the material requirements, according to the formulation of ingredients, and then mix the mixture.This method mainly considers the particle size, fluidity and bulk density of powder.The particle size of the powder determines the gap between the filled particles and also affects the bridging effect.It is better to use mixtures immediately and not leave them too long.Prolonged placement can cause moisture and oxidation.
2, the suppression process needs to understand the suppression method: one-way suppression and two-way suppression.Due to different pressing methods, the internal density distribution of the product is also different.Simply put, for unidirectional pressing, as the distance from the punch increases, the friction on the inner wall of the die reduces the pressure, and the density varies with the pressure.
3. Lubricants are usually added to the powder to facilitate pressing and demoulding.Lubricants reduce the friction between powders at low pressure stage and increase the density rapidly in the process of pressing.However, during the high pressure phase, as the lubricant is filled in the gap between the powder particles, it can, on the contrary, hinder the density of the product.Controlling the release force of the product avoids surface defects caused by the demoulding process.
4. In the pressing process, it is necessary to confirm the weight of the product, which is very critical, because the pressure instability in many factories will lead to a large weight difference, which directly affects the performance of the final product.The pressed product must be blown off the remaining powder and impurities on the surface of the product and placed neatly in the appliance to prevent impurities.
Post time: Mar-10-2021