Sand casting is an extremely flexible casting process. In this process, the sand serves as the raw material to produce a mold. And then the liquid metal fills the mold, forming parts or components. With the help of sand casting, you could make the production come true as your needs.
Generally speaking, the sand casting comes mainly in two types: traditional sand casting and digital sand casting. These two terms are exactly our topic today. This guide mainly explains these two terms in the matter of definition and production steps.
Traditional Sand Casting
The traditional sand casting method usually takes eight steps. The technician drafts the original design drawing. With such a design drawing, you could create a mold by cramming sand around the model. And secondly, you should topple the molten metal into the mold, which will cool and solidify to be a finished part or component.
The traditional sand casting is essentially the manual labor work. It takes much more time to produce a product. Sometimes, it will take up to six weeks from start to finish. The following tells its eight detailed steps of the traditional sand casting.
Eight Steps of the Traditional Sand Casting
- Sand Mixing: To begin with, you should prepare several kinds of sand needed. And then a sand mixer comes to show its value or role. With a sand mixer, you could fully mingle the appropriate amounts of clay with the several kinds of sand.
- Mold Making: In accordance with the drawing design, the production of the mold and core box can be available. In the current market, the majority of mold can be manufactured with the engraving machines. That greatly lessens the period of production to 2 to 10 days.
- Modeling or Core Making: The modeling is a crucial link in the process of casting. Detailly dividing, this step has small three links, namely Modeling ( making a cavity of the casting from molding sand ); Core-Making ( doing the interior shape of the casting ); Mold Matching ( placing the core into the cavity, simultaneously closing the upper and lower sandboxes).
- Melting: To begin with, you should calculate the reasonable mixing proportion of the required materials. Next, you could choose a suitable melting furnace to process the material. Finally, the desired metal liquid can be available. It must be noted that mixing proportion and temperature must be under accurate control. Considering the eco-friendly factor, It is only the cupola or electric furnace that serves as the optimum container to deal with the materials. Nowadays, the electric furnaces take up the market, with the cupolas gradually banned.
- Pouring: To pour the metal liquid of the electric furnace into the mold by resorting to using a ladle. There is a kind warning that such deed is of risk, so pay attention to safety!
- Cleaning: After pouring, there needs a span of time to wait for the molten metal to congeal. Next, removing the gate with a hammer and shaking off the sand on the casting. And then using the sandblaster to carefully processing the sand in the narrow split. In this way, the casting surface will be very clean.
- Casting Processing: After the cleaning process, it is inevitable that there are some casting can’t reach the standard. In such a case, simple processing may be required. Commonly, the technician will seek to apply a grinding wheel or a polishing machine to remove burrs, making the casting surface smoother.
- Casting Inspection: Generally speaking, some unqualified castings have already been found in the stage of cleaning. However, there are some castings needed to be tested in the practical application. For example, according to the standard, one casting must capable to let a 5 cm shaft pass through its center hole. In this case, you should fetch a 5 cm shaft to have a try.
With the advancement of technology, the traditional sand casting is gradually replaced by another casting method. And then let us move into the next part – Digital Sand Casting
Digital Sand Casting
Digital sand casting is also known as a fast casting. It is an improved version of the traditional sand casting method. It utilizes the sand-like materials as the medium, including the silica sand, ceramics, and even metal particles. This high-tech uses a binder polymer to stick together the particles, forming a physical 3D model.
With the digital sand casting technology, a mold can be available just within a few days. By virtue of such an advantage, the digital sand casting has come as an ideal choice for manufacturers to produce the castings in large numbers.
Six Steps of the Digital Sand Casting
- 3D Printing: A recoater smears the particulate material over the whole build space in a very thin layer. And then, a printing head locates binder to the specific area in which a component will be made later. Continually repeating these two steps until the entire component has been constructed. Last but not least, there must be a need to remove the loose particulate material from the component. To this end, you could resort to the utilization of a sandblaster.
- Blacking: Making a black coater in the core so that the core could withstand the relatively high thermal loads.
- Installing the Core: The 3D-printed sand core can also match with a traditionally manufactured mold. That means the traditional sand casting method could match in collaboration with the 3D sand casting method.
- Turbine Wheel Casting: Nearly all commonplace alloys can be molded out of the 3D-printed cores. It must be noted that different sand particles can generate different surface qualities.
- Removing the Core: The digital or 3D sand casting belongs to a lost-mold casting method. This point resembles the traditional sand casting method.
- Post-Processing: The high accuracy of casting parts greatly save the efforts to conduct the post-processing work. Given such a fact, even complex geometry graph with undercut can be printed as a single piece.
Now, I guess that you have had a relatively detailed understanding of the types of sand casting. If you want to learn more, please log in to our official website or just leave a comment below.