Sand Mould Casting Is The Most Widely Used Casting Method

- Nov 01, 2017 -

Sand mold Casting can be divided into manual sand casting and machine sand mold casting. The former is mainly applicable to single piece, small batch production and production of complex and large castings, Sand Casting the latter mainly applies to mass production. All casting methods different from sand casting are collectively called special casting. such as metal mold casting, pressure casting, centrifugal casting, investment casting, low pressure casting. Sand mould Casting is still the most widely used casting method at home and abroad.

Sand mould Casting is a casting process method for making mould with sand as main moulding material. Sand casting is widely used, at present more than 90 of castings are produced by sand casting method.

Sand casting process mainly consists of the following parts: sand-making type, molding core, sand-type and core drying, closed-box, smelting metal, pouring, falling sand and cleaning, inspection. However, it should be noted that sometimes a specific casting process does not necessarily include all of the above content, Sand Casting such as casting without inner wall without the need for core, wet casting sand type without drying. Molding process is the production method and process of casting, Sand Casting and it is the most important part of sand mould foundry process. It packs: the manufacture of sand-type, manufacturing core, and gating system, riser, vent and the production of the box.

Sand Mold Casting is a lot of modeling methods, can be divided into manual modeling and machine modeling two major categories.

1 hand styling. It refers to the full use of manual or manual tools to complete the molding process. Handmade modeling According to the model is divided into modeling, sand-digging modeling, mold modeling, live block modeling three box modeling and other methods. The manual modelling method is more flexible, Sand Casting the adaptability is strong, the production preparation time asks short, but the production rate is low, the labor intensity is big, the casting quality is poor. Therefore, the manual modelling is used for single piece small batch production. In mass production, the machine modeling method is widely used. 2 Machine modelling. It refers to the machine to complete or at least complete the operation of the molding process. Through the completion of sand, vibration, Sand Casting compaction and the steps to complete the modeling work. The machine modelling must use the template modelling. The mould is realized by separating the formwork from the sand box mechanically.

The mould used in sand casting is generally composed of the outer sand type and the core. In order to improve the surface quality of castings, a coating is often painted on the sand type and core surface. Sand Casting The main components of the coating are high refractoriness, high-temperature chemical stability of good powder materials and binders, but also add a convenient coating of the carrier (water or other solvents) and a variety of additives.

Characteristics of sand mould casting:

The strength of ① chemically hardened sand is much higher than that of clay sand, and after being made into sand, it is not required to be repaired after being hardened to a very high strength. Therefore, the mold can accurately reflect the size and contour shape of the appearance, Sand Casting in the later process is also difficult to deformation. The castings have a higher dimension precision.

② because the viscosity of the binder and hardening agent is not high, it is easy to mix with sand grains, sand mixing equipment structure lightweight, small power and high production rate, sand treatment work part can be simplified.

③ mix of sand in the hardening before there is a good fluidity, Sand Casting molding sand is easy to Chung, and thus does not need a large and complex modeling machine.

④ Use chemical hardening sand molding, according to the production requirements of the selection of materials, such as wood, plastic and metal.

The content of binder in ⑤ chemical hardened sand is much lower than that of clay sand, in which there is no powder-like material, such as the original sand with the same grain size, Sand Casting the clearance between sand grains is much larger than that of clay sand. In order to avoid casting metal infiltration between sand grains, sand or core surface should be coated with good quality coating.

Chemical hardening sand with ⑥ water glass as binder is low cost and no odor in working environment. However, after the casting of the cast metal mold sand is not easy to collapsibility, Sand Casting used old sand can not be directly recycled, must be recycled treatment, and the regeneration of water glass sand is more difficult.

⑦ Resin as binder of the chemical hardening sand cost is higher, but after pouring castings easy and type sand separation, casting cleaning work reduced, and used most of the sand can be recycled recycling.