The Research Of Plastic Mould’s Failure Mechanism And Cladding’s Reproducing Technology

The thesis introduces the type of plastic mould, S-STAR, the main failure type ofplastic mould and the common repair method of mould; studies the failure mechanism oferosion wear about plastic mould; optimizes technological parameter of laser claddingfor repairing plastic mould; presents several methods of structure design for mould basedon remanufacturing technology. All the above contents can be generalized the followingfour respects.1.Analyzing the basic failure type of plastic mould, they are surface wear andcorrosion, breakage, deformation and accidental damage. Among them, surface wear andcorrosion is the most common failure type, it is about40-50%. The author gives severalcommon repair methods of plastic mould, such as strengthen by fitting outline border,insert method, hammering method, etc.2.Studying the surface wear and erosion of plastic mould, reaching the main reasonof surface roughness increasing and out of tolerance during the process of plastic mouldusing is oxidation-erosion wear; putting forward surface oxidation mould and plasticbrittle loss mould and using them to explain the mechanism of oxidation-erosion wear;and the analysis shows that the main reason of oxidation-erosion wear is temperature andthe impact velocity, material, hardness, plasticity and toughness of plastic particles.3.Applying the finite element simulation of temperature field into the process ofsurface laser cladding, which plastic mould material P20is cladding with alloy powderH13. In a given conditions of the laser powder and spot diameter, doing the temperaturecalculating for scanning speed of different laser, getting the breadth depth ratio underevery speed, calculating approximate dilution ratio by formula, and getting the functionalequation between the speed of laser scanning and approximate dilution ratio byMATLAB. According to the speed of laser scanning calculated by actual requireddilution ratio, optimized the technological parameter of laser. The degree of closenessbetween approximate dilution ratio and actual dilution ration is proved by experimentalanalysis, and the rationality of the optimized laser scanning speed is analyzed by thehardness measurement of cladding layer and residual stress testing.4.Putting forward the importance of plastic mould reproducing which is affected bymould standardization and serialization of mould reproducing during the design stage ofplastic mould, according to the study of plastic mould’s structural features which is basedon the reproducing technology.