Mould is the basic process equipment of industrial prod […]
Mould is the basic process equipment of industrial production. The quality of the mould determines the quality of the product. Therefore, the mould is called the "mother of all industries".
The life of the mould refers to the number of products processed before being scrapped due to mould wear or other forms of failure under the premise of ensuring that the qualified product is produced. The life of the mould is divided into two stages: abnormal stage and normal stage. The abnormal stage means that the mould cannot be put into production without reaching a recognized life under a certain industrial level. The specific forms are: (1) plastic deformation; (2) fracture; (3) severe local wear. The normal stage refers to the failure of production due to slow plastic deformation or uniform wear or fatigue fracture after mass production.
A simple analysis of the impact on the mould life is as follows:
1. The influence of the mould structure:
a reasonable mould structure can make the mould work uniformly, not easy to load, and less stress concentration.
2. The working conditions of the mould affect:
⑴The material and temperature of the forming part. When forming a high-temperature workpiece, the mould will heat up due to the heat, the strength will decrease, and plastic deformation will easily occur.
⑵If the upsetting force is too large, the deformation is too large, and the mould is easy to fracture longitudinally or transversely.
⑶The surface finish of the material or the degree of oxalic acid coating is good or bad, and the surface of the mould is easy to scratch or fray.
⑷During operation, mould installation, product debugging, improper debugging of the front and back of the body, the mould is easy to be damaged or the mould mouth collapses.
⑸The higher the strength of the material being processed, the greater the force that the mould can bear, and the geometrical size of the mould is easy to wear out.
⑹The pressure of the pressing wheel is too large, the tail of the material is not round, and the unevenness has a horseshoe, which is easy to scratch the mould.
⑺ When the heater electrode is in contact with the material to ignite, the material burns and causes pitting to scratch the mould.
3. Equipment characteristics:
The higher the equipment speed, the easier it is to break or deform the mould.
Good lubrication can directly reduce the direct contact between the mould and the blank, reduce frictional heat and punching force, reduce the forming force, reduce the temperature of the mould, and significantly increase the service life of the mould.
⑴The thread rolling machine has poor precision, large vibration and abnormal operation.
⑵The mould alignment is not correct, the rolled part is displaced axially, and the teeth are subjected to two stresses: shearing and extrusion.
⑶ The size of the extruded parts is uneven and the surface is not cleaned.
⑷Drying the cymbal without lubricant during rolling will cause the tip temperature to rise sharply, causing inverted or taper teeth.