sand casting

Resin-bonded sand core manufacturing a variety of resin sand cores. Core hardening in the core box and then be removed to ensure the Core shape and size are correct. According to hardening methods, resin sand core manufacturing generally be divided into hot-and cold-box system, the core-box system, the core of two ways. hot-box core rule of law: 50 end of this decade. Usually furan resin as the core sand binder, which also joined the latent hardening agent (such as ammonium chloride). Core making, the so-box maintained at 200 ~ 300 , core sand core box after the injection, ammonium chloride at higher temperatures and resin in the reaction of free formaldehyde in acid, so that cores will soon harden. Stripping strength of the establishment of about 10 to 100 seconds. The legal system with hot-box core, Core of the dimensional accuracy is relatively high, but the process complicated and expensive devices, energy consumption and more emissions irritant gas, is also very poor working conditions of workers. Cold-box core rule of law: the late 60s. With the urethane resin as core sand binder. Method has been applied the system core, the core box without heating, to which the steam blowing amine could be a few seconds to make Core hardening. This method of energy, environment, production efficiency, etc. are better than hot-box method. 70 mid-blowing sulfur dioxide has emerged hardened furan resin cold-box method. The hardening mechanism completely different from the urethane cold-box method, but the process the characteristics, such as hardening fast Core strength higher, then with the urethane cold-box process roughly the same.

The early 20th century foundry industry began to use rolling wheel sand mixer sand, so that the quality of green sand greatly improved. Novel High Power Mixer Mixer can work to achieve high efficiency and high quality. To shock-based real jarring appearance of compaction-type molding machine, but also significantly improved the compaction mold and uniformity. With the right casting dimensional accuracy and surface quality requirements increase, which led to compaction-based high-pressure molding machine. With high-pressure molding machine manufacturing clay wet sand, not only can improve the casting dimensional accuracy, surface quality improvement, but also compaction mold moves to simplify, shorten the cycle, so that shape, combined-type the whole process to achieve high-speed and automation. The impact of a new type of gas pressure molding machine, using clay slurry thixotropy, imposed by the instantaneous pressure of 0.5 MPa are very close to the mold. These developments are the wet clay, sand casting can meet the requirements of modern industry an important condition. This traditional craft methods and thus has been used to produce large amounts of high-quality castings.

Wet clay to clay and sand the right amount of water as a major sand binder, made of sand in the wet state directly after the Lower-type and casting. Wet-type casting a long history and a wider application. The strength depends on the wet sand and water, according to a certain percentage of clay, a mixture of clay slurry. After that is a good sand mixed with a certain strength, actually made of sand by Chung, you are ready to meet the combined type and casting requirements. Therefore, the amount of sand in the clay and water is very important process factors.
Wet clay, sand casting has the advantage of: the clay is rich in resources and cheap. used clay sand wet sand after appropriate treatment, most can be collected for reuse. short cycle mold manufacturing, high efficiency. can use sand mixed with a good long time. sand beyond, Chung actually suffer a small amount of deformation without damage to the Taper and the next are very conducive to the core. The disadvantage is that: When sand to thick clay slurry coating the sand surface, the need to use a rub the role of high-power equipment, sand, or can not be of good quality sand. As the sand mixed with a very high after a good strength, modeling is not easy when the movement of sand is difficult Chung real, hand-shape when it is laborious and it takes a certain skill, molding machines, when the equipment complexity and size. mold stiffness is not high, less dimensional accuracy of castings. castings prone to red sand, gravel, holes and other defects.

The basic raw materials, manufactured sand is sand casting sand and molding sand binder. The most commonly used casting sand is silica sand. High temperature properties of silica sand can not meet the use requirements when using zircon sand, chromite sand, sand and other special corundum sand. In order to made of sand and core with a certain intensity, in the handling, combined type and pouring liquid metals without distortion or damage, generally by adding sand in the foundry binder, the loose sand bonded together into sand. The most widely used molding sand binders is clay, it can use a variety of drying oil or semi-dry oil, water-soluble silicates or phosphates, and various synthetic resin for molding sand binder. Sand casting used in the outer sand by sand binder used in different ways and build strength into the wet clay, sand, clay, dry sand, and chemical hardening of sand 3.

Steel, iron, and most non-ferrous alloy castings are available in sand casting method. As the sand casting molding materials used in cheap, easy to mold manufacturing, casting a single piece of production, batch production and mass production are able to adapt to a long time, has been the basic foundry processes.
Generally used in sand casting mold and core sand from the outside combination. In order to improve the surface quality of casting, often in the sand mold and core surface layer of paint brushes. The main components of coatings of high refractoriness, high temperature chemical stability and good powder material and binder, plus there is also easy to apply a defined carrier (water or other solvent), and various attachments.

Sand casting - castings produced in the sand casting method.