|
Casting mold as the "mother of the casting", its importance in the process of casting can be seen. Hot-box as the core of the casting mold, is the key of the sand core production. It is not only the premise of getting various types of casting sand core, and its "genetic" on the casting dimension accuracy, surface roughness and even some casting defects (example wallet sand, etc.) have a directly relationship.In my factory’s casting production, the water jacket sand core as the most important part and the most complex structure of the cylinder blank, its sand core technology used legal hot box core,and heat-curing method using gas heating. The water jacket sand core’s quality plays a vital role in the cylinder block’s production and the using of the following process. The water jacket sand core quality directly depends on the operating characteristics of the hot box tooling. Therefore, this paper chooses the operating characteristics of the hot box tooling on the water jacket sand core’s making process.In this paper, we aiming at the actual water jacket core making production process exists three problems causes are elaborated and solution design:In 1, in the using process of the hot core box for water jacket core making, because of the gas pressure mutation, burning mouth arrangement unreasonable, combustion nozzle clogging, in the core outing of the mold, the equipment bearing structure is irrational and workshop hot box process layout is not scientific and other aspects of the comprehensive effect, causing the hot core box occur the top plate bending deformation, which eventually leads to the water jacket core bending and deformation.Solution:the hot core box should adopt the electric heating mode, improving the combustion nozzle structure to prevent sand, the layout of combustion nozzle should considering the sand core’s wall thickness and the uniformity of heat throughout the heating surface to reduce thermal distortion, the core shooting machine’s bearing structure should be designed into big flat-contact, the core shooting machine’s production layout should be set in a space where the air flows slowly. In 2,the welding process of the shooting plate which is cooling by water on the water jacket core’s hot core box, leading to the final physical dimensions does not match the production design and drawings, the structural strength of the shooting plate designs unscientific,resulting in frequent water leakage, which enters the tooling within the portion resin sand moisture content is big, cause the sand core curing is not uniform; in addition, the water jacket core in hot core box body heat storage and heat conductivity of the design deficiencies, as well as the combustion nozzle arrangement and plugging problems caused the water jacket core partial curing degree differently, resulting in the water jacket core local burning skin, partially cured the problem of incomplete.Solution:improvement the shooting plate’s welding production process which is cooling by water, improve the mechanical properties of shooting plate. According to the sand core’s wall thickness and size select of exhaust plug quantity and layout, using the exhaust plug to adjust the sand core is heated evenly and sand core sand shooting compaction.In3, because the water jacket core’s structure for the cylinder body is so complicated, and it’s size is so compact,based considering the actual situation of production of the water jacket core, the sand shooting nozzle’s size, numbers, arrangement are according to the water jacket core structure optimization design, but in the actual production process, the sand shooting mouth near the box cavity due to sand flow in long time friction, local wear, severe wear parts of the core directly change the sand out of the normal mode gradient, leading to water jacket core appear a crack in the top.Solution:adjust the shooting nozzle’s size, minimize the sand flow radiation area, reducing wear. For wear parts, using spray welding process to repair, the design process should be designed as a living piece of structure, in order to facilitate the production and application.Through this topic research, can give us in the future of gas heating hot core box tooling design, production and improve the process to provide some theoretical reference, while in the actual production process, help us to fast and accurate analysis of hot core box tooling in the process of the use of the cause of the problem, guide us how fast to develop effective solutions, and ultimately improve the hot core box tooling stability.
|