Design And Research Of The Die-casting Machine Punch With Bionic Self-lubricating

As China’s accession to the WTO, the market is fully opened. With thedevelopment of vehicle industry, household appliances and electroniccommunications in domestic, the rapid development of foundry has achieved theunprecedented achievement, but there are some gaps comparing abroad, mainly interms of production costs and performance quality die castings. It is necessary tofurther improve product quality, reduce production cost for vendors to get the benefits.Due to working on high temperature, high pressure and high speed, the die castingmachine punch is extremely easy to wear in the die casting production, and it directlyaffects the quality and service life of the die-casting production efficiency and cost.Therefore, this paper aimed at the main failure mode of die casting machine punch,combined with the principle of bionics, through processing in die-casting machinepunch surface bionic structure to improve the service life of the die casting machinepunch and performance. Comparing to the mechanical property of bionic structuresamples which made of HHD and H13steel at high temperature in this paper, fatiguetest, friction and wear test had been done respectively in order to apply in die castingmachine punch with self-lubricating, and then discussed the respective change lawand mechanism, optimized the surface bionic structure shape and size. Meanwhile, themechanics analysis of the bionic die casting punch was done us ing finite elementsimulation software-ANSYS to optimize once again.By analysis and comparison, HHD steel is superior to the H13steel at hightemperature mechanical properties. With the increase of testing temperature, HHDsteel high temperature impact toughness was increased, however, H13steel wasdecreased significantly when the testing temperature exceed550℃compared withHHD steel. Although the tensile strength of H13steel is higher than HHD, however,as the temperature increases, the toughness of H13steel began to seriously reduce,and the HHD steel toughness is increased; H13steel is higher than HHD steel at hightemperature of the friction coefficient and wear rate. In addition, HHD steel had oneof the most excellent mechanical properties at560℃tempering.By researching the influence of a single bionic structure on the fatigue testperformance of the sample, it can be obtained: bionic round hole structure cansignificantly improve the anti-fatigue performance of sample, and fatigue resistanceof the worst triangle hole sample. Due to the round hole structure mechanics characteristics which can eliminate the stress concentration, the structure can breakdown, or partially offset thermal stress inside the material resulting in delaying thegrowth of fatigue crack. Moreover, it can be seen that samples of fatigue crackinitiated mostly in grain boundary owing to the stress distribution changed by thebionic structure, and that lead to the thermal fatigue crack being transgranular.According to a certain size and configuration in the sample surface processingbionic round hole structure, and expedition found their wear properties at roomtemperature: due to the bionic round hole structure with collecting andaccommodating the wear of the abrasive dust or hard abrasive, the structure canreduce the contact area between the abrasive wear and wear quantity of sample,therefore, comparing to the smooth tablet sample, the bionic round hole sample hasexcellent wear resistance. Because the round hole diameter2mm sample would soonbe abrasive dust jam in the process of wear and tear, it can’t effectively reduce thehard abrasive, scratches and plough grooves on the surface of the specimen. So thewear-resisting performance is not ideal; Due to the small contact area for grindingdisc, round hole diameter4mm specimen bore larger pressure, contributed to the wearand tear; Aperture3mm sample showed good abrasion resistance, especially theaperture3mm,4mm sample hole spacing of wear-resisting performance is best,friction coefficient and wear volume is minimum. The wear form of flat specimenstructure surface is mainly adhesive wear and abrasive wear, at the same time there isan obvious surface fatigue wear and oxidation wear; it can be concluded that the wearmorphology is quite smooth on the bionic round hole structure sample surface, andthe main wear form is adhesion wear, furthermore, abrasive wear and fatigue wear arerelatively flat surface sample slightly.By researching wear property of the bionic samples with filling with solidlubricant, it can be obtained: diameter3mm,4mm sample hole spacing and diameterof4mm,2mm hole spacing, sample have good self-lubricating ability, low frictioncoefficient and wear quantity. The wear forms are mainly adhesion wear, slightabrasive wear, and abrasive wear occurs mostly around the hole.Through bionic die-casting punch the mechanics strength analysis using finiteelement analysis software module of ANSYS-Workbench, simulated the best ofwear-resisting performance and self-lubricating of aperture3mm,4mm bionicdie-casting punch hole spacing and lubricating the best pore diameter4mm,2mmhole spacing, and it can be obtained: pore diameter3mm,4mm hole spacing ofbionic die-casting machine punch have better mechanical strength, lower stress and strain under tensile and compression state comparing to pore diameter4mm,2mmhole spacing, and therefore it is more suitable for serving in bad working conditions indie casting production.