Introduction of several molding methods in the hot

Introduction to several modeling methods in modern casting

the modeling methods used in foundry factories have not changed much in the past ten years, but the modeling technology has made great progress. Wet sand molding, precision sand molding and lost foam casting are described as follows

1. wet sand molding method. Mount company believes that among the molding methods applicable to most metal materials and mass production, clay wet sand molding is the most economical molding method. If the foundry is equipped with the control device of the latest technology, it should be done step by step. The best performance can be obtained repeatedly with the green sand control technology. These control devices include screening and separating metals, cooling of recycled sand, accurate release of additives during mixing of recycled sand, etc

macler Assoc believes that in wet sand molding, vertical parting and horizontal parting are compared. For the foundry factories that produce medium and small-scale gray iron or ductile iron parts in large quantities, heavy direct parting molding is dominant, because its equipment cost is relatively cheap, it can shape at high speed, it requires less personnel to clean the electromechanical regularly, and the deviation of compactness is small. However, the vertical parting process is limited in the gate scheme and shape, as well as in the use of complex cores, filter sheets, chillers, casings, and pounding cores. In addition, when the alloy with good fluidity is used for casting, due to the high static pressure of metal, it is easy to cause metal penetration and sand sticking

in the manufacturing of non-ferrous alloy castings, a vertical parting molding method suitable for mass production of such alloy castings with various characteristics has been designed and is now being promoted. However, for castings with required mechanical properties, as a production method of large-scale aluminum alloy castings, the metal mold casting method still has an advantage before using this molding method to achieve a high degree of mass production

macler Assoc believes that the horizontal parting wet sand casting method is one of the favorable molding methods for medium and small batch casting plants. Whether it is the upper mold, lower mold or double-sided formwork, it is adaptable to the production of complex castings. The pattern can be changed within a cycle period, and production can be effectively carried out in short and long-term operation. However, manual operation needs mechanization. In order to ensure the production of castings with good surface and high dimensional accuracy, the whole set of equipment needs to be transformed. The selection of warm sand molding method needs to consider the following points:

◆ there should be molding equipment that can mold high-quality molds with uniform hardness

◆ the template can be replaced quickly

◆ mechanized loading and unloading of lower core and mold

macler Assoc said that in order to make the modeling degree uniform, a variety of technologies were adopted. Several automatic double-sided formwork machines adopt sand shooting and compaction methods. At this time, in order to obtain uniform mold density, sand shooting and compaction methods. At this time, in order to obtain uniform mold density, the direction of sand shooting should be perpendicular to the plate. There is also an upper molding machine and a lower molding machine. In order to make the mold density uniform, micro vibration and compaction are also adopted. In addition, in order to have strong impact when filling sand to the pattern, high compressed gas is also used

however, in order to obtain uniform mold hardness, a variety of methods are used, and one method cannot be solved for various modeling methods. In the selection of molding machine, we should investigate the foundry now in use, and test with our own appearance to observe the results

◆ fine universal testing machine plastic material selection dense sand mold

the key point of this shape and getting familiar with the equipment structure, button function and operating system that you want to operate is to use the chemical bonding mold of the cold box method. Vulcan believes that this is the revival of the casting process of aluminum alloy cylinder block and cylinder head. The reason is that this method can cast the cylinder liner in the cylinder block, and at the same time, it has the advantage of using chill to realize directional solidification

this method appeared in the 1970s. It is used for casting near net shape castings and castings with complex shapes that need to increase cores with wet sand. Now, when casting accurate castings with complex shapes and sizes, the standard method is to use the cold box molding method. Moreover, it is suitable for more alloys than sand casting. In the core making operation, it can be seen that due to the innovation of resin chemistry and molding device, the casting quality can be lower, the liquid pump for parts and components and the automatic production line of manipulator can be higher, the device can be further improved, the labor required can be reduced, and high-quality and low-cost castings can be produced. The cold box molding machine is a major variant of the core making machine. Some molding machines shape the upper mold and the lower mold at the same time, and some molding machines can produce mold stacking casting with two cavities. The third variant is to use two groups of molding machines, one is the upper mold, and the other is the lower mold

in order to improve the accuracy and minimize the flash of the parting line, these molding machines are characterized by compacting the mold in the whole process. Large molding machine is completely driven by oil pressure in order to make its action smooth and reliable. Equipped with a manipulator, it implements the operations of coating, drying, core removal, adhesive coating and box closing. With these devices, the required labor force can be reduced and the highest quality and production efficiency can be guaranteed. The condition of the mold of this cold box molding machine not only affects the surface quality of the casting and the cleaning operation, but also affects the correct assembly of the core and the position where the core makes the molding sand fluidize in the sand shooting head. Therefore, the design of the mold is very important

macler Assoc said that the cold box molding machine has several sand shooting technologies. Most molding machines, this type of molding machine, use low-pressure and large air volume to shoot sand. After each cycle, it can shoot sand. There are two or three machinery factories that do not fluidize the sand, but use "extrusion method, use patented sand shooting, low air volume and high pressure sand shooting. Some machinery factories believe that when using extrusion method to make complex molds, the sand is also easy to flow. It is best to try and compare these two technologies with their own appearance to select the best method"

the cold box molding method can produce complex molds with very accurate dimensions, but the mold cost and the cost of molding sand adhesives and catalysts are higher than the price of sand and adhesives used in green sand molding, and the molding speed of the cold box molding method is low

lost foam casting mold

vulcan lost foam casting has developed due to the improvement of equipment and raw materials, and the rate of adoption is constantly expanding. New technologies such as multi-directional filling point and immediate filling of filling sand (follow-up sand) improve the casting quality and molding speed while reducing the cost

the advantages of lost foam casting are: the foaming mold can have no slope or very small slope, and sometimes the slope can be used to make complex shapes shape, and there are degrees of freedom in design. In addition, the weight of castings can be reduced, even without machining, and castings can be made without cores. The innovation of equipment and the new development of components, coatings and filling media have improved the quality and production efficiency of castings, thus expanding the market. (end)