Among the five basic forms of mold failure, thermal fatigue failure is more likely to occur on hot-worked molds with large temperature differences between hot and cold molds, while other four different forms may appear on all types of molds. There are often close linkages between different forms of failure and facilitation between interactions.
Some groove marks caused by wear are often prone to various phenomena such as fatigue cracks and thermal fatigue cracks, and if some deep and sharp grooves are themselves, they can become the cracking point of one-time fracture. After fatigue cracks and thermal fatigue cracks appear on the surface of the part, the surface quality will be seriously deteriorated, and the phenomenon of wear will be intensified. The tip of the crack will cause various stress concentrations and will become a common source of fracture.
Although the wear of the mold will lead to the failure of important parts of the mold, under normal normal working conditions, the mold can work stably and effectively for a long time before the wear fails. In fact, the effective life of the molds we talk about is mostly determined by the wear failure. For these molds, the wear failure of plastic molds refers to their normal loss of performance, and the effective wear life is the basis for determining the expected life of the mold.
The effective life of some heavy-duty molds such as cold extrusion molds is mainly determined by fatigue failure. The effective life of some molds with large temperature difference between cold and heat, such as die-casting molds, is mainly determined by thermal fatigue failure. Molds generally have a long effective life before fatigue and thermal fatigue failure, but we still routinely regard them as early failures of the mold. If there is a problem with the quality of the mold, or if the mold is debugged or used improperly, plastic deformation and product failure failure may occur at different stages of mold use, and once it occurs, the consequences are likely to be fatal to the mold. They are also the main form of failure in the early stages of mold formation.
How to ensure and improve the life of injection molding molds, on the one hand, through various ways to ensure and improve the wear resistance of important parts of the mold as much as possible, so that the mold has sufficient hardness to prevent wear and reduce life, on the other hand Various measures must be taken to prevent the early failure of various parts of the mold, and to ensure that the mold can operate safely and stably during the effective service life.