What Is The Difference Between Casting And Die Casting?

 

Casting is a manufacturing process that liquid material poured into a mold which has a hollow cavity of desired shape. Then, the part is solidified. The casting part is ejected or took out of the mold to finish the process. Casting materials are usually metals or materials mixing two or more components. For example, epoxy, concrete, plaster and clay. Casting is widely used to make parts with complex shape as these parts are difficult or not economical to be produced by other manufacturing methods. For example, heavy part like machine tool, propellers and more. Casting process has around 7,000 years history. Metal casting was widely used to make tools, weapons and religious in the past. These stuffs were often made from a copper alloy with lead.

 

Metal casting is a process that metal is heated unit in liquid and then poured into the mold. The mold includes the desired shape, runner and risers which enable the metal to fill the mold. The mold and the metal are cooled until the metal part is solidified. The casting part is recovered from the mold. And the excess material which created by the casting process will be removed by subsequent operations.

 

Concrete and plastic resin casting use single use molds, multiple use molds, or other mold made of flexible material. When the plaster or concrete is being cast, the surface is flat and not transparency. Usually, some treatment will be applied to the surface. For example, painting and etching. These treatments will make the surface have metal or stone look. Casting concrete make it possible to build sculptures, fountains or outdoor seating.

 

Raw casting contains irregularities and access ports for pouring material into the molds. The cutting, grinding, shaving and sanding away unwanted bit is called fettling. As the technology developing, the robotic processes are able to complete repetitive parts of the fettling process. Fettling adds the cost of the resulting part significantly. Manufacturers need minimize the cost by the shape of the mold, the material being cast and decorative elements.

 

Die casting is a manufacturing process that force the molten metal into the mold cavity by high pressure. The mold cavity is built with two hardened too steel dies what are machined into shape and work like an injection mold during the die casting process. Zinc, copper, aluminium, magnesium, lead, pewter and tin alloys are the common materials used in die casting process. A hot or cold chamber machine will be used depends on the type pf the metal being cast. Die cast parts is simple, it involves four steps only,so the cost each item is low. Die casting is an ideal manufacturing method for small to medium size casting in high quantity. Die castings are characterized by surface finish and dimensional consistency.

 

Zinc, aluminium, magnesium, copper, lead, and tin are the main die casting alloys. Zinc aluminium, aluminium to are specific die casting alloys. Zinc is easy to cast and plate. It has high ductility and high impact strength. Aluminium is lightweight. It allows to cast parts with complex shapes and thin wall. It is corrosion resistant, high thermal and electrical conductive. Magnesium is the easiest metal to machine. It it extremely lightweight. It has excellent strength to weight ratio. Copper is hard. It has great corrosion resistance and mechanical properties. Copper super wear resistant. Silicon tombac is the strong alloy made of copper, zinc and silicon. It is an alternative for investment cast steel parts. Lead and tin have high density. They have extremely dimensional accuracy.

 

Die Casting offer many advantages. Depending on the die casting materials, die casting allows to produce parts with excellent dimensional accuracy and thin walls. Die casting parts have smooth surface. With die casting, inserts such as threaded inserts, heating elements and high strength bearing surfaces can be cast in. Die casting provides rapid production rates. Die castings corrosion rates are slower than sand castings because die casting offers smoother surface.

 

Die casting’s main disadvantage is the high capital cost. The cost of casting equipment, dies and related components are high. To make die casting more cos-effective, high volume production is needed. Die casting process is limited to high-fluidity metals. In the standard die casting process, the final casting have a small amount of porosity.

 

TEAM Rapid, as a reliable Metal Die Casting Manufacturer, we offer die casting service. If you need help on your die casting projects. Contact us at [email protected] today. 

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Casting is a manufacturing process of pouring molten metal into a mold to create a desired shape. Once the metal solidifies, the mold is removed, and the part is produced. Three similar casting processes are: die casting, investment casting, and sand casting. Selecting the appropriate casting method for your project is as important as selecting the best metals for each casting type. Below is a description of each casting method, with the advantages and potential disadvantages of each.

Die Casting

What is die casting? Die casting is a casting method that involves injecting molten metal under high pressure into a mold. The mold cavity is typically made of steel and has a shape that matches the desired part or product. These molds are custom made for each project. Die casting is commonly used to create complex, high-precision parts with fine detail and good surface finish.

Die casting produces metal parts with high dimensional accuracy, but is best suited to high-volume production runs of non-ferrous metals

Die Casting Advantages

One of the advantages of die casting is the ability to produce parts with high dimensional accuracy and consistency. Along with the high degree of dimensional accuracy, die casting provides the ability to cast thinner parts. The benefit of thin-walled parts is a lighter-weight part. Parts that require internal cavities and have complex shapes are also a good fit for a die-casting process.

Die Casting Disadvantages

One drawback to die casting is the scale of part sizes. It is typically limited to the production of small to medium-sized parts. Additionally, die casting molds are expensive to manufacture, but the tradeoff is reduced machining and finishing processes. The higher initial cost for the mold can be offset with high-volume production runs. Another drawback is the limit of only using non-ferrous metals such as aluminum, magnesium, or zinc. Ferrous metals typically have higher melting points than non-ferrous metals, which can limit the life of the die.

Investment Casting

Investment casting performed at MetalTek’s Wisconsin Investcast Division

The investment casting (or lost wax) process begins with creating a wax pattern of the desired part or product, coating it with a ceramic shell, and then melting the wax out to create a mold cavity.  Hot liquid metal is then poured into that mold cavity to create the final metal product.  Investment casting is like die casting in that it is ideal for intricate and tighter tolerance parts.  Small to medium-sized parts are a good fit for investment casting.

Investment Casting Advantages

Many of the same advantages exist for investment casting as die casting. These include excellent finish, tight tolerances, and reduced machining costs. One of the significant advantages of investment casting is the ability to work with ferrous metals, especially stainless steel and heat-resistant alloys.

Low to medium volume projects are ideal for investment casting. The other significant benefit is the ability to cast larger parts than die casting.

Investment casting produces parts with fine detail, excellent surface finish, and tight tolerances and is typically available in much larger sizes than parts created by die casting

Investment Casting Disadvantages

Investment casting has limitations, like other casting processes. It is typically more expensive than other casting methods, and it is not well-suited for producing extremely large parts. Additionally, investment casting molds can be complex and time-consuming to manufacture. The cycle time for investment casting is longer than other casting methods, which raises the cost. Making one investment casting is slower than a die casting. The primary reason is that the mold for each investment casting needs to be remade each time.

Sand Casting

Sand casting performed at MetalTek’s Carondelet Division

The sand-casting method forms a mold by packing sand around a pattern of the desired part or product. The pattern is then removed, and molten metal is poured into the cavity to create the final part. Sand casting is a highly versatile casting method that has flexibility when it comes to sizes, shapes, and materials required.

Sand Casting Advantages

The sand-casting method is excellent for larger parts as there is more flexibility and lower cost to produce the molds.  Lower production runs are a great fit for sand castings.  Sand casting is ideal for parts that do not require tight dimensional tolerances or high degrees of machining.

Sand casting is ideal for producing larger parts where excellent surface finish and extremely tight tolerances are not required

Sand Casting Disadvantages

As mentioned above, sand casting is typically not well-suited for producing parts with high dimensional accuracy and consistency.  The rough finishes can require additional machining, but many sand casted parts do not require smooth finishes.

Conclusion: Die Casting vs. Investment Casting vs. Sand Casting

Die casting, investment casting, and sand casting are all casting methods that have unique advantages and disadvantages.  Die and investment casting both allow for tight dimensional tolerances and are great for small, intricate parts.  Sand casting is better suited for larger parts that do not require complex machining.  Scale of production and costs come into play quickly for all three methods.  Selecting the correct casting method can be a complex decision at times, but MetalTek experts are here to support customers with investment casting, sand-casting, and centrifugal casting solutions.  

Contact us to learn more.