1. Sand mixing stage

Preparation of sand and core sand for modeling, we generally use red sand modeling, the use of coated sand to make sand core.

2. Molding stage

Moulds and core boxes are made according to the parts drawings. Generally, wooden molds can be used for single pieces, plastic molds or metal molds (commonly known as iron molds or aluminum molds) can be made for mass castings, and mold plates can be made for mass castings. Usually a set of molds includes an upper mold and a lower mold. If the structure of the mold is very complicated, there will be a slider design and a sand core setting. Sometimes it is also necessary to reinforce the core to form contours and cavities that cannot be directly produced by the upper mold and the lower mold, such as cast aluminum intercooler air chamber, cast aluminum turbocharger housing, cast aluminum cooling system accessories, etc. The molds are more complicated. The mold is protected by a mold frame or a mold frame made of wood, aluminum and steel. Large products generally use aluminum or steel mold frame.

3. Styling (core making) stage

It includes modeling (forming the shape cavity of the casting with molding sand), core making (forming the internal shape of the casting) and mold matching (putting the mud core into the cavity and closing the upper and lower sand boxes). Modeling is the key link in casting. Take a project of our American customer as an example, we look at how to make sand molds. A sand mold cavity is created by placing a mixture of red sand, clay and water on the mold. This process is generally done manually, but machinery can also be used to complete the process. After removing the mold, the red sand sand mold will have a cavity corresponding to the product made. The upper mold of the mold is laid flat and filled with red sand; the lower mold with reinforcing ribs is filled with red sand. After the filling is completed, draw out the mold plate and close the upper and lower cavity sand molds together. Some need to fasten the sand box, place the float box or run material.

4. Smelting stage

According to the required metal composition with good chemical composition, select the appropriate melting furnace melting alloy materials, the formation of qualified liquid metal (including qualified composition, temperature qualified). Melting generally uses cupola or electric furnace (due to environmental protection requirements, cupola is now basically banned, the basic use of electric furnace).

5. Pouring stage

Use an aluminum water bag to inject molten aluminum water from the electric furnace into the built model. Pouring aluminum water needs to pay attention to the speed of pouring, so that the aluminum water fills the entire cavity. The casting system is generally placed at the bottom of the sand mold cavity, so that sand can be avoided, that is, the gate; at the same time, in order to exhaust, it is necessary to set the channel exhaust on the sand mold, that is, the riser. The setting of gates and risers is a key factor in the success of castings. Dongrun Foundry experienced casting engineers monitor the process to ensure the qualification rate of castings.

6. Clean-up phase

After pouring, after the molten metal solidifies, take a hammer to remove the gate and shake off the sand of the casting, and then use a sandblasting machine for sandblasting, so that the surface of the casting will appear very clean.

7. Casting processing

For some castings with special requirements or some castings that cannot meet the requirements, simple processing may be required. Generally use grinding wheel or grinding machine for processing and grinding, remove burrs, so that the casting is more smooth. We have many skilled surface treatment workers who will perform polishing, deburring, flash, shot blasting and other treatments. If so, a clean casting with a good surface can be obtained.

8. Inspection of Castings

The inspection of castings is generally in the process of cleaning or processing, and the unqualified ones are generally found to be picked out. The castings shall not have obvious holes (pores, shrinkage cavities, shrinkage loosening, slag holes, sand holes), cracks (hot cracks, cold cracks, warm cracks), surface defects (sticky sand, scarring, sand inclusion, cold insulation), shape defects (more meat, insufficient pouring, deformation, burrs at the inlet) and other defects that seriously affect the appearance and strength of the product. At the same time, our entire quality management is strictly implemented in accordance with the requirements of the ISO9001 and IATF16949 system. The quality department of the factory is equipped with 25 people to ensure that the quality inspection and inspection of products can be 100 percent qualified.