Sand Casting Is Widely Used

- Jun 13, 2017 -

In casting production, sand casting is a common casting process. But the more complex the structure shape of the casting, the more trouble the mold shape. The rapid prototyping technology makes the difficulty of forming process irrelevant to the complexity of the physical entity shape. Sand Molding process plays an important role in casting production, which directly influences the quality level, production cost, production efficiency and environmental pollution. Sand Mold Casting method can be divided into physical hardening modeling methods and chemical modeling methods two categories. The methods of physical hardening are mainly clay sand, solid casting, V-method and freezing moulding. The clay sand type is divided into wet type, dry type and dry form. The solid model and the V method are the Unbonded method (dry sand), and the negative pressure is used. The principle of freezing modeling is water as binder. Chemical modeling methods are: water glass sand type, resin sand type. They can be divided into heat hardening, self hardening, Sand Casting blowing gas hardening, such as three kinds.

. Characteristics and technological process of sand casting

Sand-moulding-combined type-pouring-cooling-sand drop-cleaning-inspection-heat treatment-inspection-get castings

Characteristics: The use of molding sand to form a mold and pouring, Sand Casting usually refers to the sand casting process under the action of gravity.

Modeling (Core) method can be divided into manual molding (core) and machine Modeling (CORE) two categories.

It is of great importance to choose the proper molding (core) method and the correct molding (core) process to improve the casting quality, reduce the cost and improve the productivity.

(1) Handmade modelling (CORE) is the most basic method, this method adapts to a wide range, does not need the complex equipment, moreover the modelling quality generally can satisfy the craft request, therefore, so far, in the single piece, the small batch production foundry workshop, the manual Modelling (core) still occupies a big proportion. It is widely used in aviation, aerospace and navigation. Manual Molding (CORE) labor intensity, low production rate, Sand Casting casting quality is not easy to stabilize, to a large extent, depends on the level of technical skills and proficiency of workers. A lot of manual modeling methods, such as shape, scraper modeling, pit modeling, various modeling methods have different characteristics and application range.

(2) Machine modelling (core) to complete or part of the molding process, called machine modelling, compared with the manual modelling, the machine modelling production efficiency is high, Sand Casting the quality is stable, the labor intensity is low, the technical request to the worker is not as high as the manual modelling, the production preparation time is long, generally applies to a fractal surface two box modelling. Machine Modeling (CORE) is mainly applicable to large-scale production of ferrous metal castings.

Classification of sand/core manufacturing methods

In the process of producing each sand type and core, according to its own strength, the different bonding mechanism can be divided into three main categories:

(1) Mechanical bonding dosage form core----Clay core sand with clay as binder produces bonding;

(2) Chemical bonding dosage form core------core sand in the shape, core process, relying on its binder itself physical, chemical reaction to achieve hardening, so as to establish strength, Sand Casting so that sand grains firmly bonded as a whole. Organic and inorganic binder, wherein inorganic binder includes sodium silicate and silica sol, while organic binder includes hot and hard, hard and hard resin sand type (core);

(3) Physical consolidation----------------------------force-----------------

(ii) Clay wet type

1. Wet type and its characteristics

(1) Production flexibility, wide application, both manual and machine, as well as assembly line production, can produce large, can also produce small pieces, can be cast steel (medium and small-sized parts), but also cast iron, non-ferrous alloy and so on.

(2) The production efficiency is high, the production cycle is short, Sand Casting facilitates the assembly line production, May realize the mechanization and the automation, the automobile, the diesel engine, the tractor industry application broadest (300 cast iron thin crack piece).

(3) Low cost of raw materials, a wide range of sources.

(4) Saving energy, drying equipment and workshop area.

(5) The sand box has long life because it does not need drying.