Metal Casting | Refractories | Casting Metal

Work against pollution: Metal Casting companies are often pressurized and also accused of polluting the environment. Many of the associations provide technical knowledge to the companies about the disposal of pollutants. Many a times the companies who have operational centers close to each other set up a common plant to dispose off the harmful waste materials. Many of the associations have set up their own norms for the member companies.

Man power safety: Some of the associations also keep a tab on the safety of the workers. A metal casting industry is a very dangerous place to work in. the associations hence have prescribed many safety norms to the member companies.

The norms regarding safety of the environment and the safety of the workers if not followed always invite trouble from the government. If the safety norms of the associations are followed then the intervention of the government reduces considerably.

Spread of Knowledge: To make the people in the industry aware of the ongoing commercial development and technical research the associations arrange international expos and also many exhibitions. The associations also represent their member companies in many seminars organized on the international level.

Commercial Aspects: The metal casting associations work as exchange houses for commercial meetings. Many associations give sound financial information and also explains the market conditions to the member companies.

Casting Sand: Some casting sands are oil bonded and foundry mix sand. This is a mixing of oil, resin and sharp fine silica sand. Such a mix can be utilized in sand casting of all varieties of metals. Some casting sands consist of 20 percent more oil and resin as compared to other brands. The objective is to ascertain the best mix for maximum green power and the best finish for the surface, that is possible.

The oil bonded sand is a substitute for water bonded green sands to be used for casting sand. The advantage over traditional, older sands is that as water is absent, the sand does not steam like the traditional sands. This sand is more secure to use than green sand. The reason is that potentially explosive quantities of steam are not generated. Due to this dearth of steam generation and the smooth texture of the sand, the oil bonded sand results in a smoother surface finish. The novice can use these sands and get professional results.

Use of casting sand: The same techniques, patterns and tools that are used for water bonded sands can be used for oil bonded casting sands. As the sand has better adhesive properties, there are fewer hassles with loose sand in the impression. The difference is that water cannot be used to manage loose sections. However, as the self adhesion is better, there are fewer problems of crumbling.

When the oil comes in contact with molten metal, it does not burn. When the castings are being shaken out, it is advisable to take off the sand that is burned. This sand that is burned can then be mixed again in the pile of fresh sand. It reabsorbs oil and works very well. After repeated use of this sand, the oil gets depleted. In this case, around 30W of non-detergent motor oil can be used to reload the sand with oil.

Die casting is the method used for forcing molten metal into mold cavities under high pressure. Die casting is very versatile and hence, is the widest used method for casting a metal. Die casting is same as permanent mold casting the only difference is that the metal is injected into the mould at very high pressure of 10-210 Mpa. This results in a more uniform part, usually good dimensional accuracy and also good surface finish.

The different metals and alloys that can be used in die casting are zinc, aluminum, copper, magnesium, tin and lead. Ferrous metals can also be used for die casting, die casting method is generally used for applications in which a large quantity is medium or small sized parts are required with detail, good dimension and fine surface finish.

There are namely two equipments used for die casting cold chamber and hot chamber process.

Cold Chamber process: In the cold chamber category of die casting, a cold chamber of each module is filled with molten metal. The time exposure provided for the molten metal to plunge the walls of the mold is less. This clod chamber process method is very useful for metals like aluminum, copper and metals that easily alloy with iron at high temperatures.

Hot Chamber process: In the hot chamber process method of die casting, the pressure that is connected to the die cavity is forever and permanently in molten metal. As the plunger moves towards the open position that is towards the non - pressurized area, the inlet port connected to the pressurizing cylinder is uncovered.

The die casting molds which are used in this method are expensive and take usually take long production time. These die casting modules are also called as “dies’

Advantages of Die Casting: The method of die casting gives excellent dimensional accuracy. The dimensional accuracy is as good as 0.1mm for the first 2.5cms and 0.005 for the first inch. Die casting also provides with smooth cast surfaces. Small and thin walls and can be made using the method of die casting walls as tiny as 0.75mm approximately can be casted. Inserts like thread insert, high strength bearing surfaces and heating elements can also be inserted using the Die Casting method. Die casting also helps in reducing or even completely eliminating the use of secondary machining operations. The use of Die Casting method also helps to reduce the production time and a huge number of articles can be produced in a very short time. Die casting method also helps to retain as well as increase the tensile strength of the metal. It offers tensile strength as high as 415 MPa that is 60ksi.

Disadvantages of Die Casting: The casting weight is very less hardly between 30 grams and 10 kgs. Also the size of the material that needs to be casted using the Die Casting method needs to small say around 600mm. the process of Die Casting requires high budget and can pile up high initial cost. Die Casting method makes the metal porous up to some extent. In the Die Casting method the thickest section needs to be less than 13mm or 0.5 inches.

Important steps in Resin Casting: The process of resin casting is completed in basically five important steps. The first step is to condition the resin, and then the material is transported. After the transportation of the material the three most important steps are executed. First the material is metered, then the material is mixed and then finally it is dispensed.

Conditioning process: The process of conditioning in the resin casting evenly distributes the fillers ion the mixture. The conditioning also eliminates the moisture and air. It also makes the mixture constant, and also elevates the temperature of the mixture. The process of conditioning also maintains a low viscosity in the mixture. This process is very important for complex combinations as it intensifies the quality of the product.

Process of Material Transportation: In the process of transportation of the materials, the piston pumps, screw pumps, and the gear pumps are used. For the highly viscous substances, instead of gear pumps, follower plate pumps are used.

Mixing process: The process of mixing is extremely important as it obtains an equal and stabilized reaction through all the materials. The most commonly used methods in the mixing are the static mixing tube, the dynamic blender, and the dynamic static mixing tube.

Dispensing process: The process of dispensing is the most important process in the Resin Casting. In the dispensing process the dispensing unit and the movement of the part are relative to each other.

Resin is casted through various dispensing processes like the metering systems, or sometimes the dispensing is done in a vacuum. In the industrial to cut costs and also time multiple dispensing units are used.

Research and development in gravity casting has taken an important step in making metal products a part of our day to day lives. The products used in homes, aircrafts, artifacts, automobiles have become more durable and less expensive. Cast alloy parts are formed by melting the alloy and then pouring it in a mold under heavy pressure or vacuum. Gravity casting is also known as vacuum casting. It is a technique in which large diameter filaments are used with adequate separation. This ensures that no clusters are formed and also good metal wetting of the fiber is guaranteed. This technique was first used in 1970. The gravity casting method has advantages like cost effective, good quality, and process control over other casting techniques.

Gravity casting is done in ceramic molds, sand, permanent casting and also in investment or lost wax casting. The gravity casting process was started with common steel after successful implementation it was further tried on heat resistance super alloys. With recent development and with more refined methods today even titanium alloys are being cast using the gravity casting method and using ceramic crucibles. The use of desired mold designs and also specially made unique designs enable a reduction in the metal cast to yield the given part. This also helps in reducing the amount of energy that is used in making such casting articles.

With new developments, today even computerized control of the vacuum pressure and rate is possible. This enables the user to control the filling rate. This makes casting of high quality metals like and viscous metals like metal matrix and composites of aluminum casting possible. This gravity casting method is used to produce casting worth of more than $200 million. The industry is expected to grow rapidly in the coming years due to the increase in production of automotive exhaust manifolds in stainless steel.

The first ever commercial use of this computerized technology, was made by Howmet Industries of Whitehall, Michigan. They used this technology to precisely cast and design turbine blades used in aircrafts. This technology is also being used by Ford Motors to develop and improve the casting process of light truck and automobile engine blocks.

Today, metal parts fabricated using gravity casting method is being used in 90 per – cent of all durable goods. Goods like stoves, washing machine, automobiles, refrigerators, lawn mowers, cars and even boats. Many other articles like badminton rackets, tennis rackets, and even football studs are made by using light weight metals which are gravity casting method. This gravity casting method has been used to develop metal alloy parts, which are used for the auto and airline industries, which is said to make vehicles lighter though much stronger and extremely efficient.

Alloys like ferric cast metals, casting grade iron and steel are typical metals that are used for gravity casting. Also die cast grade zinc can be cast using gravity casting method. Also other raw materials like sand, spin or plaster are used. Aluminum is also used, but it is very difficult to gravity cast aluminum a lot of care needs to be taken and proper pressure should be applied to obtain the desired shape and effect.

People who like to make their own artifacts and are enchanted with the idea of building new and useful things from scratch are sure to enjoy ‘do it yourself casting’ that can be done at home using simple methods and techniques. Many amazing things can be produced and created using you home made metal foundry and Refractories. A good understanding of some basic foundry knowledge and few simple tools can help you make metal casting at home possible. Many people find it difficult to get special parts for their cars or bikes or even find it very costly to modify their cars, house or even bikes. If you develop your hobby of metal casting, then you can easily make special parts for your cars and bikes and also will find it easy and save a lot of money. Casting can be used to make many things like, simple ornaments knobs and even handles. Hand wheels and small machinery or tools can also be made. Small articles like brass name plates, statues, vintage motorcycle and car parts, etc can also be made at home.

Furnace Designs that can be made at home:

Refractories Furnace: This is very easy to build and even a large coffee-can Refractories will serve the purpose. This can be used to build a simple gas fired furnace.

The “2 bucks” furnace: Is not as the name suggests, the furnace can’t be built in two bucks.  It refers to the design based on two buckets. It is very useful and a good experienced person can build it with a budget that is below 10 bucks. It effectively burns propane.

Flowerpot crucible furnace: This furnace can also be built very easily and most importantly, it can be built using the waste material from your back yard. All you need is an old flower pot and a few metal cans. Melt the metal cans and coat the inside of the flower pot with the melted metal Refractories and you furnace is ready.

Other types of furnaces that can be built at home are dirt and brick furnace, chimney pipe furnace and breaking metal in barbecue.

Tools and material needed:

Home made Aluminum Refractories: Pulleys of different size and shapes can be made by bending aluminum rods or plates. They are very simple to make and once you get the hang of it, you’ll enjoy making them.

Building steel crucibles: Steel crucibles are a bit difficult to make. You need to cut the steel and weld it using a welder, so it is a bit risky job and can cause injuries. It needs to be done with utmost care and precaution.

Home made ladle: A ladle can be made at home using a small portion of a steel water pipe; you can select the water pipe according to your needs and then cut it in the desired dimensions to create your home made ladle.

After doing all this basic work and gathering all the required information, you can now start your own metal Refractories casting and make desired articles. You also need to make the molds of your desired shape and size and you are ready to go. All types of Refractories metals and alloys can be used and melted for home casting, only their degree of heat required varies.