1. The characteristics and process of sand casting process
Preparation - moulding, mould assembly, casting, cooling, shakeout, cleaning, inspection, heat treatment, inspection, casting
Features: the component using sand mould and casting method, usually refers to under the action of gravity sand casting process.
Modelling (core) method can be divided by mechanized hand molding (core) and the machine model (core) two kinds big.
Choosing the appropriate modeling (core) method and the correct modelling technique (core) operation, to improve castings quality, reduce cost, increase productivity has extremely vital significance.
(1) hand molding (core) handmade molding (core) is the most basic method, this method the range is wide, do not need complicated equipment, and shape quality generally can meet the technical requirements, so, so far, in the foundry of single piece and small batch production, handmade molding (core) still accounts for a large proportion. Widely used in aviation, aerospace, navigation field. Handmade molding (core) labor intensity, low productivity, casting quality not stable, largely depends on the technical level of workers and proficiency. Manual modeling method are many, such as shape modelling, scraper, pit shape modelling, modelling methods have different characteristics and application scope.
(2) the machine model (core) use machines all or part of the modelling process, known as the machine model, compared with the manual modelling, modelling machine production efficiency is high, stable quality, low labor intensity, technical requirements for workers not as high as manual modeling, production preparation time is long, generally applicable to a parting surface modelling of two cases. Machines (core) is mainly used in the modelling with the mass production of the black metal castings.
2. The manufacturing method of sand mold/core classification
In the process of manufacture of sand mold and core, according to its own established when the bonding mechanism of different intensity, generally can be divided into three categories:
(1) mechanical bonding dosage form core - clay as binder of clay core sand binder;
(2) the chemical bonding dosage form the core, core sand in the process of modeling, core, rely on the physical and chemical reaction to the adhesive itself hardening, so as to build strength, the sand bonded firmly as a whole. Organic, inorganic binder, inorganic binder including sodium, sodium silicate and silica sol and organic binder including hot hard, since the hard and hard resin sand mold (core);
(3) physical consolidation - refers to use the force created by the physics will not including binder sand consolidation together, magnetic mold casting method, negative pressure molding method or real seal modelling method or film negative pressure molding, and mold modelling method.
(2) the wet out of clay
1. Wet type and its characteristics
(1) production flexibility, widely applicable, can be manually, machines, and assembly line production, can produce big already, also can produce small, can be cast steel (medium), also can cast iron, non-ferrous metal, etc.
(2) high efficiency, short production cycle, easy to assembly line production, which can realize mechanization and automation, automobile, diesel engine, rob tractor industry application of the most popular (300 ~ 500 kg iron thin crack).
(3) the raw material of low cost, wide source.
(4) to save energy, drying equipment and workshop production site area.
(5) because of without drying, sand box long service life.
(6) disadvantages: improper operation, easy to produce some casting defects: sand inclusion scab, rat tail, sand holes, heaving sand, adhering sand, etc.
2. The main raw materials used in the wet out of clay
Clay wet formula is: the original sand (or sand) 100, clay (bentonite) 1 ~ 5%, pulverized coal ~ 8% and ~ 6% water, as well as other additions.
Precision casting, Sand Casting, EPC Casting