Rapid Prototyping Applications in Metal Casting

And until now, the metal casting molds process was the fastest way to produce a large number of precise parts and pieces. Technology is always improving to attend to the constant growth of the market demand. Today, Rapid Casting is a development needed to ensure that the industry of metal casting keeps growing.

The usual methods, such as investment casting and vacuum casting are not particularly known for their speed. Since they need a lot of heavy and expensive material to work with, they can be really costly. So to implement them, the Rapid Prototyping process arrived with a solution. With parts being made at great speed, and increasing volume, the cost-benefit is surely taken into consideration.

But to better understand how this process helps the industry on a larger scale, we need to understand the basics. In this article, you will learn what metal casting is, how to cast metal, and the applications of Rapid Prototyping in the metal casting process. So keep reading!

What is metal casting?

Treatment of steel casting defects

Metal casting is an ancient technology. In the metal casting mold process, molten metal does pour into a mold cavity. It can cool and then remove the mold to make the metal shape.

With time, automation innovations in foundry operations have simplified the task of processing large amounts of castings while also improving its quality. Casting metals into usable items has evolved over thousands of years to become more precise and mechanized, but the underlying process has stayed virtually the same.

A brief history of metal casting

Roughly 4000 BC

The history of metal casting molds first appeared in 4000 BC. Gold was the first casting material due to the difficulty of obtaining pure ore. Then, because bronze was harder than gold, it became the metal of choice for casting.

Roughly 2000 BC

By 2800 BC, the technology of metal casting had found its way to Egypt, and efficiently conducting this procedure was enormously significant on their rise to dominance throughout the Bronze Age. The Shang Dynasty in China was the first to use sand casting while melting metals around 1300 BC. Cast iron was not used as a military instrument or ornament until the Qin Dynasty, over 300 years later.

Roughly 1000 BC

Over a thousand years later, the religions made a great impact in castings. As they used it to male art and prestige their gods, they started to use it to make their own cathedrals. Churches and cathedrals were built by the hand of casting workers.

18th century

Then the Wars started, and people learned how to make guns and cannons out of casting. During World War 1 and 2 casting was used to make military archery. Weapons and machines were being mass produced by the industry that would soon be the birth of all technology today.

Then the revolution began

All industries started to benefit from the metal casting industry. Healthcare, with machines and equipment always improving. The military, with new weapons and devices for security. And even the transports, bus and cars began to look modern and have a lot more comfort in them thanks to castings parts.

And not only jewelry or big transports use this technique. Metals die cast toys were a hit for a long time, and are still in the market to this day.

The healthcare industry also had its revolution with metal casting. New machines and equipment, always getting more precise, started being made and improving the health of people everywhere. An even in esthetics and quality of life, in dentistry.

Dentists started to use and improve cast metal partial dentures, to give people back their self-esteem and jaw integrity. A cast partial denture is a removable partial denture made of a cast metal framework with fake teeth embedded in acrylic resin.

Today, you can find metal casting things all over. From the cellphone in your hand to the equipment that transports your food up to the grocery store. So now let’s understand how to cast metal!

investment casting vs sand casting
carbon steel casting

How to cast metal?

Metal casting is a very unique and ancient technique, but the key difference between each method is usually the material for the mold or the equipment used to cast. However the process is virtually the same.
Metal casting, to this day, is used to make jewelry and art. People all around the world explore different ways to cast metal and transform it into something new. They can use water, different materials and even food to cast. But for this article keep in mind that the part ahead is about the industrial process of metal casting.

A step by step guide

1. A pattern is made

Typically, patterns are created of wood, metal, plastic, or wax. This is a critical part of the industrial metal casting world, where exact calculations are required to ensure that components fit and operate together. They are what is going to form the mold after the metal casting.

2. Sometimes parts need to be hollow

For that, a core piece is made. Usually from the same material as the mold, but in some cases, it can even be made from metal, but it must be able to come out after. This will ensure that the piece stays hollow inside and serves its purpose.

3. The metal casting part

Now, to make the metal casting mold, the part needs to be dipped in a ceramic-like substance. This process occurs many times until it reaches the needed thickness. After it is dry, the casting goes into a high-heat chamber and the pattern melts away. Now the metal casting mold is empty for the next step.

4. Pouring the metal

The metal or other material used is heated until it melts before being poured or pressed into the mold and left to solidify. After it is completely dry, the removing process begins. With pressure, shaking or fully breaking the cast the part is released. Some methods require the cast to be completely discarded, but some can actually be reused, as well as the molds.

5. Almost done!

Now to truly finish the metals die cast the fine details are fixed. The piece is cleaned and polished and now it is ready to be marketed. If any flaws are found the piece is discarded.

What difference does Rapid Prototyping make in Metal Casting?

Until not that long ago, we used to have only a few ways to do patterns for metal casting in a fast way. Making metals die cast from scratch, sculpting from metal blocks or mounting them with metal sheets.

Can you imagine making each pattern every time you needed a mold? That can take a long time and also have a high cost. Fortunately, technology moves along and the evolution to be faster and more precise everyday finally begins, with the Rapid Prototyping process.

The waiting time for a model to be manufactured may be cut in half by printing the mold components, mold halves, and cores!

With the precision these 3D printing machines can bring, less time and resources are wasted in the process, and we can still maintain the quality and precision of the mold.

And they can have different purposes too, there are 3 types of 3D printing machines used in different scenarios. Such as:

Fused deposition modeling (FDM)

The FDM machine melts thermoplastic filament before extruding it. The computer carefully controls the extrusion in line with the 3D design, producing each layer in sequence. Once all the layers are placed, the metal casting can begin.

The FDM machine has a medium variety of materials that can be printed but has good accuracy with the details. Sadly, it doesn’t support large size builds.

Selective laser sintering (SLS)

This machine makes use of printing material that is provided in powder form. The powder is melted using a laser to build each layer of the component. Fresh powder is spread over the half finished portion, and the procedure is repeated until everything is finished and ready to be cast.

This machine can comport a large range of materials to print, with good enough accuracy and large build sizes. Unfortunately, the surface finish can be poor.

Stereolithography

This one, like the SLS, also uses a laser, but in this case it helps solidify the material. After each layer is melted and placed by design the laser is activated and solidifies that layer. Then the printing machine goes to the next one, and so on. This can be a little faster as the drying happens along the way.

This machine also has a medium range of materials to be printed, but it can offer larger build sizes, as well as being one of the highest accuracies when printing. However, the stereolithography machine can be more expensive than the others.

Now we can understand how this is applied in each type of metal casting.

Types of Metal Casting

Now that you know the basic procedure for the metal casting process, and how Rapid Prototyping can help, we can explore some of the methods and what makes each one more unique than the other!

metal sand

Sand Casting – Metal Casting Sand

A method of making metal castings in a sand mold(metal casting sand). This method is best suited for delicate details and perfectly shaped patterns. It has a low subjective cost and is widely used with automotive parts and components.

Sand casting is a popular method for producing cast components. Molten metal is poured into a disposable mold made of foundry sand that contains a binder in this technique. It is mostly used for its reusable features. The mold and the casting, after broken to pieces can be remade and reused!

For this method(metal casting sand), the use of Rapid Prototyping can help speed up the process or wider the size range of the metal casting. The models can be made of rubber, paper-like materials, or even resin.

investment sanding

Investment casting

This is a procedure that includes forming patterns in soldering materials like wax, covering the surface of the design with various layers of ceramic goods, and then melting the pattern out of the mold shell to make a mold that can be filled after baking at high temperatures.

The mold in this process is made of material that can be burned away. But the Rapid Prototyping process can help create a mold that doesn’t need to be disposed of. Or the process of pattern-making can be sped up with the use of printing machines. More patterns can be made and the production rises.

Investment casting gating system design

Permanent mold casting

Metal casting molds that may be reused are used in this method. Metallic molds and cores are the immediate tools in permanent mold casting because they are reusable. Rapid prototyping technologies can be used as direct or indirect tools in the permanent mold production process. This can boost the process’s size and speed, as well as the precision and longevity of the molds.

Can all metals be casted?

Casting is a solidification process, which implies that most of the qualities of the casting are controlled by the solidification phenomena. And, with the use of heat, all metals and alloys may be liquefied and so flow, generally under the influence of gravity alone. As a result, almost any metal may be cast.

But through history, we had the tendency to study the materials we wanted to use. Heavy metals include the first metals discovered, such as iron, copper, and tin, as well as valuable metals like silver, gold, and platinum. With them came the first ornaments, weapons and equipment. With time and lots of experimentations, people started to explore other types of metal and their impurities.

Now, for every method of metal casting, there are some metals that work better than others.

Sand casting is compatible with a wide range of metals and alloys, including iron, steel, aluminum, bronze, magnesium, zinc, and tin. Manufacturing businesses may need to heat up to 3,000 degrees Fahrenheit depending on the exact metal or alloy utilized.

As for the investment casting method most common metals, such as aluminum, bronze, magnesium, carbon steel, and stainless steel can be used. Nonferrous metals, notably zinc, copper, aluminum, magnesium, lead, pewter, and tin-based alloys, are used to make the majority of die castings. A hot-chamber or cold-chamber machine is employed depending on the type of metal being cast.

We found a lot of different ways to use different materials. For every type of metal, we can find the perfect fit for it.

Can you use metal on cast iron?

Now that you know more about casting and metal casting. And yes, cast iron pans are exactly what you are thinking!

They were made with the casting technique, and can even be artisanal. There is in fact Rapid Prototyping when it comes to large brands, but they can also be made from scratch. But it is not made of pure iron, so there is some care to take.

Cast iron is a kind of iron-carbon alloy containing more than 2% to 4% carbon. There are also varying amounts of silicon and manganese in it, as well as traces of impurities like sulfur and phosphorus. Iron ore is reduced in a blast furnace to produce cast iron. The iron is then poured or cast and hardened into raw ingots. It is then remelted with scrap and alloying materials. It is then recast into molds to create a range of goods.

You can find Cast Iron in constructions, pipes, machines, and automotive parts, and also in your kitchen. It is known for its durability over time, but at the same time, it can be quite fragile. It can get very brittle so with time it was replaced by steel in construction.

Can you use a metal spatula on cast iron?

This answer might surprise you, but yes! However, it has some conditions. As soon as you get your new cast iron pan, you must season it. If you don’t, besides getting food stuck on it, you can easily make chips and risks in it.
This can be the most durable pan you will ever cook with if you take care of it right. Treat it badly and you can ruin it forever!

So here is how to season a cast iron pan:

  • Scrub it well under hot water with soap;
  • Dry it completely;
  • Coat the entire surface in vegetable oil;
  • Put it in the oven to cook upside down for 1 hour;
  • Let it cool inside the oven and repeat until it is shiny!

To clean it, don’t use soap, and be careful with the heat. The pan must always be warm enough to make scrubbing it easier, but not too hot to burn it. Always coat it with vegetable oil before cooking anything, and with time it will get even better and nothing will stick!

Applications of rapid metal casting

Rapid metal casting can use in manufacturing prototypes and short-term projects. This is the process of creating component elements to build a functional model of a product and test its functionality and limitations.
Some metal castings does use in engines that require extreme heat and cold resistance. Cast iron pipes must avoid corrosion and high pressure. Other cast parts must be lightweight and robust. The purpose of the parts is to provide precise tolerances between expansion and contraction in numerous applications.
So to see in detail where we can see the application of rapid metal casting in our lives, keep reading!

automobile

Automotive Industries

The advancements in 3D printing are having a significant influence on engineers’ capacity to test concepts and swiftly bring items to market. Because prototypes produce test results faster and in greater quantities, simple changes to the design may be made, and a new prototype can be reproduced relatively rapidly.

Most of the time, in aerodynamics and the automobile industry, it is unnecessary to test the same principles on the same material. This provides engineers with freedom since they may test the product as many times as they want using plastic and wax before releasing it to the public. 3D printing is assisting automobile engineers in hastening development and increasing efficiency.

We can see the use of these technologies in engine blocks, cooling fans, fuel caps, truck/bus air valves, gearboxes, pedals, motors, and many more components in vehicles and machines.

sand casting

Healthcare

As we evolve so does the environment around us, we discover new diseases and new weaknesses in our human bodies. To deal with all the challenges that come with living we must be prepared. Medicine is the most advanced technology we have. Today we can make things that we long before thought could only be miracles. And this is also thanks to the metal casting industry.

With new and improved equipment we can take better care of each other. And with the new technologies available, we can metal cast even the smallest of the pieces with precision. You can use Delicate procedures and treatments in the whole world with the same effect thanks to that.

We can see this clearly in pacemakers, hospital beds, stethoscopes, monitors, oxygen pumps, and the machines that treat cancers, make operations and give us another chance to live.

metal sand

Electronic devices

The proof is literally in your hands right now. The read this article you can use a smartphone, a computer, a tablet, and much more. And to think that we couldn’t use the internet in the palm of our hands, anywhere in the world, in a little more than a decade ago.

This is where most of this industry is focused on, in bringing joy and quality of life for you. Through more advanced devices and problem solving electronics, we can have a safer and smarter home.

You can think about every piece that is present in devices like your tablet, printer, headphone, smartwatches, and cameras.

metal sanding

Art

Yes, even art! We have already talked about how artisans and artists can use the metal casting methods on a smaller scale to make amazing things. And now with 3D printers becoming more and more accessible, their creativity is at its peak.

You don’t have to search too far to find someone making a mold from silicone, rubber and a lot of other materials. People make a living through their own rapid prototyping systems. There are earrings molds, unique jewelry and decorations from different types of casts, and even full art pieces. Have you ever seen those videos of people filling an abandoned ant colony with molten metal? It is a natural sculpture! As well as the metal filling its molds in metal casting, it fills every corner of the ant’s labyrinth, giving us the opportunity to learn more about the world we live in.

Why is casting preferred over the manufacturing process?

Metal Casting produces precise parts while decreasing material waste, energy consumption, and later machining. It may also ensure the production of very complicated components.

The metal casting process involves a lot of chain-like methods. It involves forging, welding, and, most commonly, stamping. Manufacturing is the metal casting process of making items using labor, equipment, tools, and biological or chemical processing or formulation.

It can refer to either the large-scale transformation of raw materials into completed goods or the development of more complicated objects by the sale of basic commodities to manufacturers for the manufacturing of items such as vehicles, airplanes, or home appliances.

So, yes. Metal casting is a type of manufacturing! The most compelling reason for manufacturers to employ casting is the incredible design freedom it provides. It is a very adaptable approach that enables the use of intricate design processes that are not possible with other ways of manufacturing. Furthermore, because it includes a relatively simple and easy production process, it allows for a quick transition from raw material to a final product.

The act of pouring something into a mold and then releasing it after is what makes it so good. Making perfect molds, with the precision of these methods, can cut the production time in a huge economic way.

When you do this metal casting process with machinery, you can expect problems with it, and be worried about hiring specialized employees to deal with it. And a single machine can cost more than it can produce in a short period of time.

Because there are no limits on the assembly of components or shapes, casting also allows for the creation of visually pleasing patterns. To get the appropriate finish from casting, a variety of casting procedures may be used. Sand molding has a rough appearance, whereas shell molding and investment casting have a smoother appearance. Casting also contributes to residual stress reduction in the finished product.

The cost reductions are the most obvious advantage of employing the casting process. Metal casting reduces fabrication costs greatly since it allows for the consolidation of several elements into a single fabrication. It also needs a shorter manufacturing lead time, which leads to lower prices. In addition, the design freedom and flexibility result in decreased machining and excess metal costs. And with the Rapid Prototyping process, these advantages only grow!

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