What is Metal Additive Manufacturing and Why is it Trending?

The additive manufacturing market is expanding rapidly and is anticipated to maintain this growth trajectory in the coming years.

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In this article, we delve into metal additive manufacturing, addressing all your questions about this trend-setting technology, its operating principles, various techniques, and how small and medium enterprises (SMEs) can leverage this accessible innovation.

Exploring Metal Additive Manufacturing

Metal additive manufacturing, or metal 3D printing, is a subset of additive manufacturing that employs a heat source, such as a laser or electron beam, to fuse metal available in powder or wire form, thereby constructing an object layer by layer.

This process allows unparalleled design flexibility and the capability to manufacture components from a variety of metal-based materials, offering several advantages.

Metal additive manufacturing contributes significantly to the growth of the manufacturing sector by enhancing efficiency, reducing waste, lowering emissions, and accelerating time-to-market for stronger and lighter components.

How Does Additive Manufacturing Operate?

In additive manufacturing technology, a digital data file guides a machine to create a three-dimensional object.

The machine constructs the object layer by layer. It begins by spreading a thin layer of raw material powder where the part will be built. This powder is then processed to form a solid shape, and the subsequent layers are built in the same manner until the entire object is complete.

Understanding Metal Additive Manufacturing Techniques

Several principal methods are driving the trend in metal additive manufacturing:

• Powder Bed Fusion Techniques: A thin powder layer is spread over the powder bed surface. High-powered thermal energy, such as a laser or electron beam, is then used to selectively fuse and sometimes melt the powder together.
• Directed Energy Deposition: Raw material is deposited through a nozzle and simultaneously melted using a heat source. This layering process yields a solid object.
• Metal Binder Jetting: Liquid binder is printed onto thin layers of powder, essentially gluing the particles together. The object is later treated, usually by sintering or infiltration, to harden it.

These methods revolutionize assembly and industrial fabrication. Utilizing computer-aided design software to guide digital hardware, metal additive manufacturing can produce detailed geometric shapes with precision. This meticulous layer-by-layer metal powder deposition enables the creation of lighter, stronger parts, providing more flexibility and efficiency to manufacturing processes.

Here are four specific types of powder bed fusion technologies used in metal 3D printing:

• Selective Laser Sintering (SLS)
• Direct Metal Laser Sintering (DMLS)
• Selective Laser Melting (SLM)
• Electron Beam Melting (EBM)

Is Metal Additive Manufacturing a Recent Innovation?

While additive manufacturing is not new—having gained traction since the 1980s—metal additive manufacturing emerged soon after polymer-based methods. The first metal 3D printed component was created using SLS in 1990.

The Evolution of Metal Additive Manufacturing

High-tech sectors like aerospace and motorsports industries were the early adopters of metal additive manufacturing.

Initial metal 3D printing ventures, particularly using SLS methods, faced challenges like the formation of "melt balls," leading to surface irregularities and affecting the object's density. This issue was mitigated by using a blend of high and low melting point powders. Over time, new methods such as DMLS, SLM, and EBM have emerged, making metal additive manufacturing increasingly mainstream thanks to more affordable materials and machinery.

Diverse Techniques in Additive Manufacturing

Several methods exist for 3D printing metal components, varying in raw materials used, heat source, and characteristics of the final solid form.

Selective Laser Sintering (SLS) in Additive Manufacturing

Developed in the 1980s by Carl Deckard and Joe Beaman, SLS employs a laser to heat powdered materials just around their melting point so they fuse without completely melting.

The unfused powder surrounding the solid form acts as a support structure, eliminating the need for additional supports. Currently, SLS is predominantly used to print plastic objects, such as those made from nylon or polyamide, which are strong, durable, UV, and heat-resistant. However, a notable drawback of SLS is that objects can be porous, a significant issue for metal applications.

Direct Metal Laser Sintering (DMLS) in Metal Additive Manufacturing

DMLS is designed for producing solid metal forms using a process similar to SLS but specifically for metals and alloys like aluminum and titanium.

A DMLS machine rolls out a thin layer of metal powder, which is heated just above melting point by a laser. This process repeats layer-by-layer until the full object is created. DMLS enables the creation of intricate and precise metal forms from prototypes to end-use products.

This advanced technique is valuable for rapid prototyping and mass production of metal parts. Unlike SLS polymer printing, DMLS often requires support structures for objects with overhangs, but the method produces components without internal defects common in traditional manufacturing, making it crucial for high-precision industries like aerospace. However, commercial DMLS printers are costly, around $500K.

Selective Laser Melting (SLM) Technique

SLM shares similarities with DMLS and SLS, but it completely melts the metal powder, producing extremely strong objects. This technique is compatible only with specific metals like stainless steel, aluminum, titanium, and cobalt chrome.

Despite SLM’s energy-intensive nature due to complete melting, it offers the advantage of creating strong parts as single forms without requiring assembly. Minor structural issues such as porosity and cracking may occur, depending on the process parameters. Most powder bed fusion machines in use today, including those by NASA for producing aerospace components, are SLM machines.

Working Mechanism of Electron Beam Melting (EBM)

EBM, similar to SLM, uses an electron beam instead of a laser to heat metal powder, resulting in very strong although less precise forms compatible with fewer metals.

Currently, Arcam is the only company manufacturing electron beam 3D printing systems, primarily utilized in aerospace and healthcare sectors.

For additional details, visit Metal Element Additives Manufacturer.

Metals in Additive Manufacturing

High-quality metal powder is crucial for effective powder bed fusion in metal additive manufacturing. Metals like titanium, steel, stainless steel, aluminum, copper, and nickel-based powders are utilized, contingent on the method applied.

Wire feedstocks, originating from the welding sector, are also gaining popularity due to their cost-effectiveness and wide range of material options, including steel and stainless-steel alloys, as well as pure metals like titanium, tungsten, and aluminum.

Advantages of Metal Additive Manufacturing

Contemporary metal additive manufacturing offers numerous benefits:

• Allows production of metal parts without traditional tooling
• Facilitates creation of intricate shapes with internal voids challenging to machine
• Complementary to conventional methods, easily integrates into existing production processes
• Faster production of unique items like replacement parts and custom goods
• Quickens prototype development
• Reduces material usage, lowering overall manufacturing costs
• Minimizes the necessity for assembly

Is Metal Additive Manufacturing Economical?

The primary drawback of metal additive manufacturing is the high initial investment in machinery, which has limited its use to high-value sectors like aerospace, defense, and medical industries.

In addition to the machine costs, expenses for training, maintenance, and consumables, along with necessary post-processing of produced items, must be considered. Nonetheless, the price of additive manufacturing is gradually decreasing, making it more accessible to smaller businesses. Thus, it's worthwhile to explore whether this technology fits your business requirements.

Sectors Utilizing Metal Additive Manufacturing

The aerospace industry was a pioneer in adopting additive manufacturing for optimizing components, leading to lighter aircraft and reduced fuel consumption.

A growing number of industries, including art, design, jewelry, medical, and engineering sectors, are utilizing additive manufacturing for creating a diverse array of objects.

Significance of Metal Additive Manufacturing for SMEs

SMEs often hesitate to adopt new technologies due to budget limitations or risk aversion. Additive manufacturing can significantly enhance product development through rapid prototyping and refinement.

As mentioned earlier, additive processes speed up production times, bringing products to market more swiftly. Additional advantages include waste minimization, essential for those working with costly materials like jewelers, and the ability to customize without re-tooling.

The decision to use additive manufacturing will depend on its suitability for achieving business goals and cost viability. Outsourcing additive manufacturing rather than internal investment might also be a feasible option.

Another critical consideration is assessing competitor strategies and determining where capital investment will offer the most significant competitive advantage.

Precious Metal Additive Manufacturing

Precious metal additive manufacturing is crucial for electronics, healthcare, and jewelry sectors.

Not all precious metals are equally suited for additive manufacturing. Below is an overview of popular precious metals—gold, silver, platinum, and ruthenium—and their application in metal additive processing.

• Silver

Silver, known for its softness and pliability yet harder than gold, boasts the highest electrical and thermal conductivity. It’s prevalent in jewelry and the photographic industry due to its light-reflecting properties. It is useful for products resistant to oxygen and moisture but less resistant to sulfurs. In additive manufacturing, silver is used for making electrical contacts and high-capacity batteries.

• Gold

Gold, valued for its malleability, non-rusting nature, tarnish resistance, and non-toxicity, is commonly used in dentistry, medicine, electronics, and intricate jewelry-making, using 18-carat gold powder for additive manufacturing.

• Platinum

Platinum, known for its flexibility, softness, density, and resistance to air and water, is employed in jewelry, surgical tools, laboratory utensils, automobile exhaust systems, electrical resistance wires, electrical contact points, optical displays, and LCD screens.

• Ruthenium

Ruthenium, a tough white metal derived from nickel, copper, and platinum ore processing, resists tarnishing at room temperature and is highly demanded in the electronics and chemicals industries.

Case Study: Additive Manufacturing's Impact

Three engineers from Melbourne, passionate about cycling, utilized additive manufacturing to create a premium bike frame locally in Australia.

Their challenge was constructing an ultra-light yet visually appealing bicycle frame acceptable to the market. Using titanium components and carbon fiber tubing, they leveraged additive manufacturing techniques to develop and market a high-performance road bike.

Bastion Cycles initially outsourced its additive manufacturing but soon brought the process in-house. This decision allowed for rapid prototype redesigns and explorations, leading to successful market entry.

Additive manufacturing enabled the production of thin frame walls (0.25 to 1.5mm) and customizable geometry, providing new business opportunities. The company's website offers an online tool for customers to design and follow the production process of their bike frame.

For more information, feel free to reach out to Alloy Supplier.