Aluminum Investment Casting

Aluminum Investment Casting we called here is American style silicon gel process(with green wax and better sand) with very good smooth surface, tight tolerance, suitable for small part making widely used for stainless steel. It’s different with Russian style investment casting actually called soluble glass process(with white wax and rough sand)with relative rough surface, bigger tolerance, suitable for large part making more than 1.00KGS especially for carbon steel, alloy steel, sometimes also for ductile iron and grey iron

Aluminium casting foundry

NINGBO INNOVAW MECHANICAL is a professional supplier for casting and machined part which is widely used for Automobile, Medical, earthmover, petroleum, electricity Industry. Dedicating in long-term business with foreign customers from North America and west Europe, we are exactly know what’s the customer requirement when they provide drawings and material specification. And our engineering can suggest the best process and technology to make the component or any design changing if necessary. Most of our products are exported to Canada, USA, and west Europe Germany, France, Italy, Norway, Finland, Switzerland, etc. and win good reputation among our customers.

NINGBO INNOVAW cover different foundry and machining factory based on different casting process: investment casting, sand casting and pressure die casting, gravity casting, as well as precision machining with CNC machines. Our MOTTO is: Quality first, with competitive price and delivery in time. If you need some casting or machined part OEM or aftermarket, INNOVAW will be the best choice for you…

STEEL CASTING

Casting is a manufacturing process in which molten metal is poured into a mold, allowed to solidify within the mold, and then the mold is broken and the solid piece is taken out. Casting is used for making parts of complex shape that would be difficult or uneconomical to make by other methods.

Steel Casting are especially adapted for parts that must withstand wear, shocks or heavy loads. They are stronger than either wrought iron or cast iron. or malleable iron and are very tough. High alloy Steel castings can be heat treated to bring about the diffusion of carbon or alloying elements, softening, hardening, stress relieving, toughening, improve machinability, increase wear resistance, and removal of hydrogen entrapped at the surface of the casting.

Type of Casting

Plain Carbon Steel Castings
High Alloy Steel Castings

Manganese Steel Castings

Hi Chrome Castings

Ni-Hard Castings

SG Iron Castings

Stainless Steel Castings

Heat Resistant Cast Steel

high pressure die casting

Mould design: Our engineers and technical staff will collaborate with a client's own engineers on the design of low pressure die casting to ensure smooth production and optimum performance of the finished product.

Our engineers designed mould by PRO/ENGINEER, SOLIDWORKS, UNIGRAPHICS and simulation analysis software to be sure the quality and high efficiency before tooling machining. Mould cavity and frame will be machined by automatic CNC milling center, CNC turning lathe, EDM , wire cutting machines. Our experiences and technology will be great helpful for you.

alloy die casting

Our factory have Large spectrum of alloy die casting machines,it can produce Variety of alloy die casting available to meet in house production requirements and to provide quality custom-made die-casting parts for other industries

Improper use of aluminium

Improper use of aluminium may result in problems, particularly in contrast to iron or steel, which appear "better behaved" to the intuitive designer, mechanic, or technician. The reduction by two thirds of the weight of an aluminium part compared with a similarly sized iron or steel part seems enormously attractive, but it must be noted that this replacement is accompanied by a reduction by two thirds in the stiffness of the part. Therefore, although direct replacement of an iron or steel part with a duplicate made from aluminium may still give acceptable strength to withstand peak loads, the increased flexibility will cause three times more deflection in the part.

Where failure is not an issue but excessive flex is undesirable due to requirements for precision of location, or efficiency of transmission of power, simple replacement of steel tubing with similarly sized aluminium tubing will result in a degree of flex which is undesirable; for instance, the increased flex under operating loads caused by replacing steel bicycle frame tubing with aluminium tubing of identical dimensions will cause misalignment of the power-train as well as absorbing the operating force. To increase the rigidity by increasing the thickness of the walls of the tubing increases the weight proportionately, so that the advantages of lighter weight are lost as the rigidity is restored.

In such cases, aluminium may best be used by redesigning the dimension of the part to suit its characteristics; for instance making a bicycle frame of aluminium tubing that has an oversize diameter rather than thicker walls. In this way, rigidity can be restored or even enhanced without increasing weight The limit to this process is the increase in susceptibility to what is termed "buckling" failure, where the deviation of the force from any direction other than directly along the axis of the tubing causes folding of the walls of the tubing.

The latest models of the Corvette automobile, among others, are a good example of redesigning parts to make best use of aluminium's advantages. The aluminium chassis members and suspension parts of these cars have large overall dimensions for stiffness but are lightened by reducing cross-sectional area and removing unneeded metal. As a result, they are not only equally or more durable and stiff than the steel parts they replace, but they possess an airy gracefulness that most people find attractive. Similarly, aluminium bicycle frames can be optimally designed so as to provide rigidity where required, yet exhibit some extra flexibility, which functions as a natural shock absorber for the rider.

The strength and durability of aluminium varies widely, not only as a result of the components of the specific alloy, but also as a result of the manufacturing process. This variability, plus a learning curve in employing it, has from time to time gained aluminium a bad reputation. For instance, a high frequency of failure in many poorly designed early aluminium bicycle frames in the 1970s hurt aluminium's reputation for this use. However, the widespread use of aluminium components in the aerospace and high-performance automotive industries, where huge stresses are withstood with vanishingly small failure rates, illustrates that properly built aluminium bicycle components need not be intrinsically unreliable. Time and experience has subsequently proven this to be the case.

Similarly, use of aluminium in automotive applications, particularly in engine parts that must survive in difficult conditions, has benefited from development over time. An Audi engineer, in commenting about the V12 engine--producing over 500 horsepower (370 kW)--of an Auto Union race car of the 1930s that was recently restored by the Audi factory, noted that the engine's original aluminium alloy would today be used only for lawn furniture and the like. As recently as the 1960s, the aluminium cylinder heads and crankcase of the Corvair earned a reputation for failure and stripping of threads in holes, even as large as spark plug holes, which is not seen in current aluminium cylinder heads.

One important structural limitation of an aluminium alloy is its fatigue properties. While steel has a high fatigue limit (the structure can theoretically withstand an infinite number of cyclical loadings at this stress), aluminium's fatigue limit is near zero, meaning that it will eventually fail under even very small cyclic loadings, but for small stresses this can take an exceedingly long time.

die casting Shrinkage

Castings shrink when they cool. Like nearly all materials, metals are less dense as a liquid than a solid. During solidification (freezing), the metal density dramatically increases. This results in a volume decrease for the metal in a mold. Solidification shrinkage is the term used for this contraction. Cooling from the freezing temperature to room temperature also involves a contraction. The easiest way to explain this contraction is that is the reverse of thermal expansion. Compensation for this natural phenomenon must be considered in two ways.

Solidification Shrinkage

The shrinkage caused by solidification can leave cavities in a casting, weakening it. Risers provide additional material to the casting as it solidifies. The riser (sometimes called a "feeder") is designed to solidify later than the part of the casting to which it is attached. Thus the liquid metal in the riser will flow into the solidifying casting and feed it until the casting is completely solid. In the riser itself there will be a cavity showing where the metal was fed. Risers add cost because some of their material must be removed, by cutting away from the casting which will be shipped to the customer. They are often necessary to produce parts which are free of internal shrinkage voids.

Sometimes, to promote directional solidification, chills must be used in the mold. A chill is any material which will conduct heat away from the casting more rapidly that the material used for molding. Thus if silica sand is used for molding, a chill may be made of copper, iron, aluminum, graphite, zircon sand, chromite or any other material with the ability to remove heat faster locally from the casting. All castings solidify with progressive solidification but in some designs a chill is used to control the rate and sequence of solidification of the casting.

Patternmaker's Shrink (Thermal Contraction)

Shrinkage after solidification can be dealt with by using an oversized pattern designed for the relevant alloy. Pattern makers use special "contraction rulers" (also called "shrink rules") to make the patterns used by the foundry to make castings to the design size required. These rulers are 1 - 6% oversize, depending on the material to be cast. These rulers are mainly referred to by their actual changes to the size. For example a 1/100 ruler would add 1 mm to 100 mm if measured by a "standard ruler" (hence being called a 1/100 contraction ruler). Using such a ruler during pattern making will ensure an oversize pattern. Thus, the mould is larger also, and when the molten metal solidifies it will shrink and the casting will be the size required by the design, if measured by a standard ruler. A pattern made to match an existing part would be made as follows: First, the existing part would be measured using a standard ruler, then when constructing the pattern, the pattern maker would use a contraction ruler, ensuring that the casting would contract to the correct size.

Precision CNC Machining Components

Machining directly from rod bar directly or from investment casting, die casting, sand casting, etc. By CNC turning lathe, milling center, or drilling, tapping, grinding etc. different material including ferrous metal(iron, steel, stainless steel) and non-ferrous(aluminum, brass).

Aluminum die Casting

Aluminium die casting,aluminum die casting process is always used for heavy part with big wall thickness and very strong mechanical property after T6 heat treatment. Its also better to avoid porosity inside casting after secondary machining. Gravity casting part is nice looking with better surface than sand casting, but sand casting is more flexibility even it is very complicated shape. 356 T6 is the most common raw material.

Pressure die casting(Aluminum alloy)

Pressure die casting(Aluminum alloy)

In the pressure die casting process the metal is forced into a high grade steel tool at high speed and pressure. The casting temperature is roughly 700°C when casting aluminum and 650°C when casting magnesium. The use of vacuum casting technique is a must in order to achieve superior quality for extremely light and thin walled components.

Pressure die casting is a competitive casting method when the components are needed at high volumes or when better tolerances and surface finish are required than can be achieved by gravity die casting. The need for machining is very low due to the close casting tolerances. Heat treatment of pressure die casting is not possible but due to the high rate of solidification the mechanical properties are good. The tooling costs are considerably higher than for gravity die casting.

Important applications are found in the components for mobile telephone base stations and certain mobile telephone applications. The more important reasons for using light metal casting are low weight, mechanical strength, stiffness and electrical properties. Other applications are e.g. components for the power transmission line in the vehicle industry and electronics industry.

Ductile iron

Much of the annual production of ductile iron is in the form of ductile cast iron pipe, used for water and sewer lines. Ductile iron pipe is stronger, easier to tap, requires less support and provides greater flow area compared to pipe made from other materials. In difficult terrain it can be a better choice than PVC, concrete, polyethylene or steel pipe.

Castings made of ductile iron are widely used. Examples include automobile components, industrial machinery, wind turbine electrical energy generation, valves, air conditioning machinery, lawn and garden equipment, and agricultural products.

Cast iron

Silicon is essential to making of grey cast iron as opposed to white cast iron. When silicon is alloyed with ferrite and carbon in amounts of about 2 percent, the carbide of iron becomes unstable. Silicon causes the carbon to rapidly come out of solution as graphite, leaving a matrix of relatively pure, soft iron. Weak bonding between planes of graphite lead to a high activation energy for growth in that direction, resulting in thin, round flakes. This structure has several useful properties.

The metal expands slightly on solidifying as the graphite precipitates, resulting in sharp castings. The graphite content also offers good corrosion resistance.

Graphite acts as a lubricant, improving wear resistance. The exceptionally high speed of sound in graphite gives cast iron a much higher thermal conductivity. Since ferrite is so different in this respect (having heavier atoms, bonded much less tightly) phonons tend to scatter at the interface between the two materials. In practical terms, this means that cast iron tends to “damp” mechanical vibrations (including sound), which can help machinery to run more smoothly.

All of the properties listed in the paragraph above ease the machining of grey cast iron. The sharp edges of graphite flakes also tend to concentrate stress, allowing cracks to form much more easily, so that material can be removed much more efficiently.

Easier initiation of cracks can be a drawback once an item is finished, however: grey cast iron has less tensile strength and shock resistance than steel. It is also difficult to weld.

Grey cast iron's high thermal conductivity and specific heat capacity are often exploited to make cast iron cookware and disc brake rotors.

Rolling-element bearing

A rolling-element bearing is a bearing which carries a load by placing round elements between the two pieces. The relative motion of the pieces causes the round elements to roll (tumble) with little sliding.

One of the earliest and best-known rolling-element bearings are sets of logs laid on the ground with a large stone block on top. As the stone is pulled, the logs roll along the ground with little sliding friction. As each log comes out the back, it is moved to the front where the block then rolls on to it. You can imitate such a bearing by placing several pens or pencils on a table and placing your hand on top of them. See "bearings" for more on the historical development of bearings.

A rolling-element rotary bearing uses a shaft in a much larger hole, and cylinders called "rollers" tightly fill the space between the shaft and hole. As the shaft turns, each roller acts as the logs in the above example. However, since the bearing is round, the rollers never fall out from under the load.

Rolling-element bearings have the advantage of a good tradeoff between cost, size, weight, carrying capacity, durability, accuracy, friction, and so on. Other bearing designs are often better on one specific attribute, but worse in most other attributes, although fluid bearings can sometimes simultaneously outperform on carrying capacity, durability, accuracy, friction, rotation rate and sometimes cost. Only plain bearings have as wide use as rolling-element bearings.

aluminum

aluminum (ulOO'minum) [key], called in British countries aluminium (ăl"yOOmin'ēum) [key], metallic chemical element; symbol Al; at. no. 13; at. wt. 26.98154; m.p. 660.37°C; b.p. 2,467°C; sp. gr. 2.6989 at 20°C; valence +3.

Aluminum is a silver-white metal with a face-centered cubic crystalline structure. It is a member of Group 13 of the periodic table. It is ductile, malleable, and an excellent conductor of heat and electricity. The pure metal is soft, but it becomes strong and hard when alloyed. Although less conductive than copper wire of the same diameter, aluminum wire is often used for high-tension power transmission because it is lighter and cheaper. Although it is chemically very reactive, aluminum resists corrosion by the formation of a self-protecting oxide coating. It is rapidly attacked by alkalies (such as lye) and by hydrochloric acid.

Although it is the most abundant metal in the earth's crust (about 8% by weight), aluminum does not occur uncombined but is an important constituent of many minerals, including clay, bauxite, mica, feldspar, alum, cryolite, and the several forms of aluminum oxide (alumina) such as emery, corundum, sapphire, and ruby. Commercially, aluminum is prepared by the Hall-Héroult process, which consists essentially of the electrolysis of alumina prepared from bauxite and dissolved in fused cryolite. In an electric furnace an iron tank lined with carbon serves as the cathode and large blocks of carbon serve as the anode; the electric current generates enough heat to keep the cryolite melted. Molten aluminum collects at the bottom of the tank, and oxygen is liberated at the anode. The anode is consumed as it combines with the oxygen to form carbon dioxide

Die casting

Die casting is the process of forcing molten metal under high pressure into the cavities of steel moulds. The moulds are called dies. Dies range in complexity to produce any non-ferrous metal parts (that need not be as strong, hard or heat-resistant as steel) from sink faucets to engine blocks (including hardware, component parts of machinery, toy cars, etc). In fact, the process lends itself to making any metal part that:

must be precise (dimensions plus or minus as little as 50 µm--over short distances),
must have a very smooth surface that can be bright plated without prior polishing and buffing,
has very thin sections (like sheet metal--as little as 1.2 mm),
must be produced much more economically than parts primarily machined (multicavity die casting moulds operating at high speed are much more productive than machine tools or even stamping presses),
must be very flexible in design; a single die casting may have all the features of a complex assembly.
If several machining operations would be required or assembly of several parts would be required (to make a finished part), die casting is probably far more economical. This level of versatility has placed die castings among the highest volume products made in the metalworking industry.

Common metals used in die casting include zinc and aluminum. These are usually not pure metals; rather are alloys which have better physical characteristics.

In recent years, injection-molded plastic parts have replaced some die castings because they are usually cheaper (and lighter--important especially for automotive parts since the fuel-economy standards). Plastic parts are practical (particularly now that plating of plastics has become possible) if hardness is not required and if parts can be redesigned to have the necessary strength.

Sand casting

Sand casting requires a lead time of days for production at high output rates (1-20 pieces/hr-mold), and is unsurpassed for large-part production. Green (moist) sand has almost no part weight limit, whereas dry sand has a practical part mass limit of 2300-2700 kg. Minimum part weight ranges from 0.075-0.1 kg. The sand is bonded together using clays (as in green sand) or chemical binders, or polymerized oils(such as motor oil. Sand in most operations can be recycled many times and requires little additional input.

Preparation of the sand mold is fast and requires a pattern which can "stamp" out the casting template. Typically, sand casting is used for processing low-temperature metals, such as iron, copper, aluminum, magnesium, and nickel alloys. Sand casting can also be used for high temperature metals where other means would be unpractical. It is said to be the oldest and best understood of all techniques. Consequently, automation may easily be adapted to the production process, somewhat less easily to the design and preparation of forms. These forms must satisfy exacting standards as they are the heart of the sand casting process - creating the most obvious necessity for human control.

[edit] Plaster casting (of metals)
Plaster casting is similar to sand molding except that plaster is substituted for sand. Plaster compound is actually composed of 70-80% gypsum and 20-30% strengthener and water. Generally, the form takes less than a week to prepare, after which a production rate of 1-10 units/hr-mold is achieved with items as massive as 45 kg and as small as 30 g with very high surface resolution and fine tolerances.

Once used and cracked away, normal plaster cannot easily be recast. Plaster casting is normally used for nonferrous metals such as aluminium-, zinc-, or copper-based alloys. It cannot be used to cast ferrous material because sulfur in gypsum slowly reacts with iron. Prior to mold preparation the pattern is sprayed with a thin film of parting compound to prevent the mold from sticking to the pattern. The unit is shaken so plaster fills the small cavities around the pattern. The form is removed after the plaster sets.

Plaster casting represents a step up in sophistication and requires skill. The automatic functions easily are handed over to robots, yet the higher-precision pattern designs required demand even higher levels of direct human assistance.


Casting of plaster, concrete, or plastic resin
Main article: Resin casting
Plaster itself may be cast, as can other chemical setting materials such as concrete or plastic resin - either using single use waste molds as noted above or multiple use piece molds, or molds made of small ridged pieces or of flexible material such as latex rubber (which is in turn supported by an exterior mold). When casting plaster or concrete the finished product is, unlike marble, relatively unattractive, lacking in transparency, and so is usually painted, often in ways that give the appearance of metal or stone. Alternatively, the first layers cast may contain colored sand so as to give an appearance of stone. By casting concrete, rather than plaster, it is possible to create sculptures, fountains, or seating for outdoor use. A simulation of high quality marble may be made using certain chemically set plastic resins (for example epoxy or polyester) with powdered stone added for coloration, often with multiple colors worked in. The later is a common means of making attractive washstands, washstand tops and shower stalls, with the skilled working of multiple colors resulting in simulated staining patterns as is often found in natural marble or travertine.


Shell moulding
Shell molding is also similar to sand molding except that a mixture of sand and 3-6% resin holds the grains together. Set-up and production of shell mold patterns takes weeks, after which an output of 5-50 pieces/hr-mold is attainable. Aluminium and magnesium products average about 13.5 kg as a normal limit, but it is possible to cast items in the 45-90 kg range. Shell mold walling varies from 3-10 mm thick, depending on the forming time of the resin.

There are a dozen different stages in shell mold processing that include:

initially preparing a metal-matched plate
mixing resin and sand
heating pattern, usually to between 505-550 K
inverting the pattern (the sand is at one end of a box and the pattern at the other, and the box is inverted for a time determined by the desired thickness of the mill)
curing shell and baking it
removing investment
inserting cores
repeating for other half
assembling mold
pouring mold
removing casting
cleaning and trimming.
The sand-resin mix can be recycled by burning off the resin at high temperatures.

Casting

Casting is a manufacturing process by which a molten material such as metal or plastic is introduced into a mold, allowed to solidify within the mold, and then ejected or broken out to make a fabricated part. Casting is used for making parts of complex shape that would be difficult or uneconomical to make by other methods, such as cutting from solid material.

Casting may be used to form hot, liquid metals or meltable plastics (called thermoplastics), or various materials that cold set after mixing of components such as certain plastic resins such as epoxy, water setting materials such as concrete or plaster, and materials that become liquid or paste when moist such as clay, which when dry enough to be rigid is removed from the mold, further dried, and fired in a kiln or furnace.

Substitution is always a factor in deciding whether other techniques should be used instead of casting. Alternatives include parts that can be stamped out on a punch press or deep-drawn, forged, items that can be manufactured by extrusion or by cold-bending, and parts that can be made from highly active metals.

The casting process is subdivided into two distinct subgroups: expendable and nonexpendable mold casting: