Introduction to lost mold casting

Since dry sand without binder often shows signs of collapse during the pouring process, the so-called "magnetic forging" was adopted by a. ittemoser of Germany in 1967.In 1971, Japan's Nagano found V method (vacuum forging method), enlightened by this, tomorrow's die forging in many places also take vacuum pumping method to firm molding sand.As a result, over the past 20 years, the technology of vanishing die casting has grown rapidly on a global scale.High precision die forging of casting is a new process with nearly no margin and accurate cut molding. This process does not require mold taking, parting surface or sand core, so there is no flash, burr or drawing inclination of casting, and the size deviation caused by core combination is reduced.The roughness of casting can reach Ra3.2 to 12.5 microns.Casting dimension accuracy can reach CT7 to 9.Processing allowance of up to 1.5 to 2mm, can greatly reduce the cost of machine processing, and the traditional sand forging method, can reduce 40% to 50% of the machine processing time.

The proposed flexibility provides a substantial degree of freedom for the proposed casting layout.It is capable of forging very large castings through a combination of foam die sheets.

The sand core without traditional forging will not present the uneven casting wall due to the size of sand core or the location of the bottom core.

Clean production sand without chemical binder, high temperature foam is harmful to the situation, the old sand take over 95%.Reduce investment and production cost to reduce the weight of casting blank, machine processing allowance is small.Die forging process, like other forging processes, has its error, error and scope.First according to the following factors to consider whether to take such a process.1. The larger the casting batch, the more considerable the economic benefits.2. Casting materials with good and bad usability are generally as follows: gray cast iron -- non-ferroalloy -- plain carbon steel -- nodular cast iron -- low carbon steel and alloy steel;Through the process needs to organize so as not to lead to process trial, debugging cycle is too long.3. Casting size should first consider the utilization scale of response equipment (such as vibrating table and sand box).4. Casting layout the larger the casting layout, the better the advantages and economic benefits of die forging process can be demonstrated. For the environment with narrow internal cavity passage and interlayer on the layout, the requirements of die die process should be pre-improved, so as to be put into production.Introduction to vanishing die casting die forging technology more and more performance of the upper hand, many small and medium-sized enterprises one after another into production.Especially in recent years, die forging manufacturers have mushroomed, which can be seen from the ordering demand of die forging equipment manufacturers [2].But there are also a lot of die forging enterprises put into production soon after the dispute.To disappear in this notice is that many enterprises grasp die forging process is not deep, head looks fade with die forging process is very simple, no full predicts its discipline and large, the horse, results in the real production encountered unexpected problems, don't intentionally organize management, to present the topic of helpless and helter-skelter.The results will not only waste time, money and spirit, but also lose the market.In practice, die forging is a system project that can actually be used to produce all kinds of castings, and it has achieved universal success in the test chamber.But, because our country die die forging mould material widely adopt the packing foam polystyrene (EPS), and the common coating craft haven't without forming craft, combined with dry sand vibration craft and die die forging process is not mature, which caused many enterprises, at the beginning of good taste is familiar with these small and medium-sized enterprise is not deep, to is another coax will present rush down the passive situation of ostentation and extravagance.Experts suggest that the offshore casting of property still need not exhaust efforts for better development in the future.