3d Metal Printing Technology

3d Metal Printing Technology

Rajaneesh N Marigoudar1, Nisar ahamed G2, Bharath G N3, Akash M4, Mohammed Arfathulla5

Mechanical Engineering Department, JIT, Davangere-577003, Karnataka, India

Abstract: Layer-by-layer printing is used in three-dimensional (3D) metal printing, sometimes referred to as metal additive manufacturing, to produce intricate metal objects. It is a fast-developing technology that has transformed the industrial sector by making it feasible to produce specialised and complicated metal components that were previously unattainable. A laser or electron beam is used in 3D metal printing to melt and fuse different kinds of metal particles together to form the required shape. Compared to conventional production techniques, this technology offers several benefits, such as less material waste, better productivity, and more design freedom. Numerous industries, such as aerospace, medicine, and the automotive sector, use 3D metal printing.

1. Introduction:

   A cutting-edge technology called three-dimensional (3D) metal printing, also known as metal additive manufacturing, allows for the layer-by-layer printing of intricate metal parts. By enabling the creation of complex metal components that were previously impossible to make using conventional techniques, this technology has completely changed the industrial sector. To get the required form, the technique requires melting and fusing several kinds of metal powders with a laser or electron beam. Compared to conventional production, 3D metal printing has several benefits, such as increased design freedom, less material waste, and increased productivity. The technique has a wide range of uses in fields including aircraft, medicine, and automobiles. Before the technology is fully realised, there are still obstacles to be overcome, like cost and scalability.

   Fig.1 3D Metal Printing.

   The two main categories of metal additive manufacturing procedures are those based on powder bed fusion (PBF) and those based on directed energy deposition (DED).

   1. Powder Bed Fusion based technologies (PBF):

      PBF stands for Powder Bed Fusion, which is a type of metal 3D printing technology that uses a laser or electron

      final product. The process starts with a layer of metal powder being spread across the build plate. The laser or electron beam is then directed onto the powder, melting it in specific areas to create the desired shape. Once a layer is complete, the build plate moves down and a new layer of metal powder is spread on top, and the process is repeated until the final product is complete. PBF can produce extremely complex and precise metal components with superb accuracy and precision. The process allows for a wide range of metals to be used, including titanium, stainless steel, and aluminium. PBF is frequently utilised in sectors including aerospace, healthcare, and automotive that demand very precise metal components. However, the process can be slow and expensive, and post- processing is often required to achieve the desired surface finish.

      Fig.2 Powder Bed Fusion process.

   2. Direct Energy Deposition (DED):

      A focused energy source, such as a laser or electron beam, is used to deposit metal powder or wire using direct energy deposition (DED), a form of metal 3D printing method. Sometimes the procedure is referred to as Direct Metal Deposition (DMD) or Laser Metal Deposition (LMD).

      DED uses a process that includes melting the metal wire or powder as it is being deposited, which enables the precise

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      beam to selectively melt layers of metal powder to create a

      fabrication of massive, complicated metal components.

      A mobile nozzle is used in the procedure to layer-by-layer deposit the material onto the construction platform. The deposited material is subsequently melted using the energy source, solidifying the link between the layers.

      DED has the capacity to produce metal parts of all sizes, from tiny components to massive buildings.

      Fig 3. Direct Energy Deposition (DED) process.

2. TYPES OF 3D METAL PRINTING:

   1. Selective Laser Sintering (SLS)

   2. Selective Laser Melting (SLM)

   3. Direct Metal Laser Sintering (DMLS)

   1. Selective Laser Sintering (SLS):

      Selective Laser Sintering (SLS) is a type of 3D printing technology that uses a high-powered laser to selectively fuse a layer of powdered material into a solid part. A construction platform is covered in a thin coating of powder, which is then layer by layer melted and fused using a laser in designated locations to create the final item.

      SLS can create intricate, high-resolution parts from a variety of materials, such as metals, ceramics, and polymers. The process allows for the creation of parts with intricate geometries and internal structures that are difficult or impossible to produce using traditional manufacturing techniques.

      SLS is widely used in industries such as aerospace, automotive, and medical for the production of prototypes, end- use parts, and tooling. The technology offers several advantages, including the ability to produce functional parts with high accuracy and consistency, and the ability to use a variety of materials.

      Fig 4. Selective Laser Sintering (SLS)

      However, SLS also has some limitations, such as the need for post-processing to remove excess powder and achieve the desired surface finish. The process can also be slow and costly, especially when producing large or complex parts. Nonetheless, SLS remains an important technology for the manufacturing of highly customized and intricate parts.

   2. Selective Laser Melting (SLM):

      SLM (Selective Laser Melting) is a metal 3D printing technology that uses a high-powered laser beam to selectively melt and fuse metal powder particles layer-by-layer to create a final product. The process starts with a thin layer of metal powder being spread over the build platform, and the laser beam is directed onto the powder, melting and fusing the metal particles together in specific areas to create the desired shape. The process is repeated layer-by-layer until the final product is complete.

      SLM is capable of producing high-precision and complex metal parts with excellent accuracy and surface finish, making it a popular technology in industries such as aerospace, medical, and automotive. SLM has the ability to create parts using a variety of metals, such as titanium, aluminium, stainless steel, and more.

      The capacity to produce items with intricate interior features and complicated geometries that are hard to obtain using conventional manufacturing techniques is one of the major benefits of SLM. Additionally, SLM reduces material waste, improves design flexibility, and allows for the production of custom metal parts on-demand.

      Fig 5. Selective Laser Melting (SLM) process. 207

      However, SLM has some limitations, such as the need for post-processing to achieve the desired surface finish, high cost, and limited production speed. Nevertheless, SLM is a crucial technology in the metal 3D printing industry and is continually advancing to overcome these limitations and expand its range of applications.

   3. Direct Metal Laser Sintering (DMLS):

      DMLS stands for Direct Metal Laser Sintering, which is a type of metal 3D printing technology that uses a laser to selectively fuse layers of metal powder to create a final product. The process involves spreading a thin layer of metal powder across a build platform and then using a laser to melt specific areas of the powder to create the desired shape. Once a layer is complete, a new layer of metal powder is spread on top, and the process is repeated until the final product is complete.

      DMLS is able to create very detailed & intricate metal parts with excellent accuracy and precision. The process allows for a wide range of metals to be used, including titanium, stainless steel, and aluminium. DMLS is commonly used in industries such as aerospace, medical, and automotive, where high-precision metal parts are required.

      DMLS provides a number of benefits over conventional production processes, including less material waste, more design freedom, and better productivity. However, the process can be slow and expensive, and post- processing is often required to achieve the desired surface finish.

      Despite these challenges, DMLS is an important technology for producing complex and customized metal parts. It offers significant advantages over traditional manufacturing, and as the technology continues to develop, it is likely to become an even more important part of the manufacturing industry.

      Fig 6. Showing the DMLS process.

3. GENERAL WORKING OF METAL 3D PRINTING:

Metal 3D printing, also known as metal additive manufacturing, involves the creation of complex metal parts through layer-by-layer printing. There are several different types of metal 3D printing technologies, including powder bed fusion (PBF), direct energy deposition (DED), and direct metal laser sintering (DMLS).

In PBF, the process starts with a layer of metal powder being spread across the build plate. The laser or electron beam is then directed onto the powder, melting it in specific areas to create the desired shape. Once a layer is complete, the build plate moves down, and a new layer of metal powder is spread on top, and the process is repeated until the final product is complete.

In DED, a movable nozzle deposits metal powder or wire layer-by-layer onto the build platform. The energy source, such as a laser or electron beam, is then used to melt the deposited material, creating a strong bond between the layers.

In DMLS, a laser is used to selectively fuse layers of metal powder to create the final product. The process involves spreading a thin layer of metal powder across a build platform and then using a laser to melt specific areas of the powder to create the desired shape. Once a layer is complete, a new layer of metal powder is spread on top, and the process is repeated until the final product is complete.

Even though these methods are different, the overall operation of metal 3D printing is the layer-by-layer deposition of metal material utilising an energy source, such as a laser or electron beam, to melt and fuse the material together. The result is a sophisticated, personalised metal part that may be used to a variety of fields, including aerospace, medicine, and the automobile industry.

PRINTER PARAMETERS:

The printer parameters of 3D metal printing can vary depending on the specific type of metal 3D printing technology being used. However, there are several key parameters that are commonly used in most metal 3D printing processes. Some of these parameters include:

1. Layer height: This parameter determines the thickness of each layer that is deposited onto the build platform.

2. Laser power: This parameter determines the intensity of the laser used to melt the metal powder or wire. 208

3. Scan speed: This parameter determines the speed at which the laser or electron beam moves across the metal powder or wire, melting it in specific areas.

4. Hatch distance: This parameter determines the distance between each pass of the laser or electron beam, ensuring proper coverage of the metal powder or wire.

5. Powder bed temperature: This parameter controls the temperature of the metal powder bed, ensuring proper melting and bonding of the metal material.

6. Preheat temperature: This parameter controls the temperature of the build chamber, ensuring that the metal material is heated to the appropriate temperature before the printing process begins.

7. Gas flow rate: This parameter controls the flow of inert gas, such as argon or nitrogen, which is used to prevent oxidation of the metal material during the printing process.

These printer parameters are critical in ensuring the successful printing of high-quality metal parts. Optimizing these parameters can result in parts with improved mechanical properties, surface finish, and dimensional accuracy.

4. COMMONLY USED METAL POWDERS IN 3D MATEL PRINTING:

There are several types of metal powders that are commonly used in 3D metal printing. The choice of metal powder will depend on the specific application and the requirements of the final product. Here are some of the most commonly used metal powders in 3D metal printing:

1. Titanium: Titanium is a strong, lightweight metal that is commonly used in the aerospace and medical industries.

2. Stainless steel: Stainless steel is a corrosion-resistant metal that is commonly used in a range of industries, including automotive and medical.

3. Aluminium: Aluminium is a lightweight metal that is commonly used in the aerospace and automotive industries.

4. Cobalt-chrome: Cobalt-chrome is a high-strength, wear-resistant metal that is commonly used in the medical industry for applications such as orthopaedic implants.

5. Inconel: Inconel is a high-temperature, corrosion- resistant metal that is commonly used in the aerospace and automotive industries.

6. Copper: Copper is a highly conductive metal that is commonly used in the electronics industry.

7. Gold: Gold is a highly conductive and corrosion- resistant metal that is commonly used in the electronics industry.

These are just a few examples of the metal powders that can be used in 3D metal printing. Other metals, such as nickel, silver, and platinum, Depending on the exact application, can also be employed. The choice of metal powder will depend on factors such as the mechanical properties, corrosion resistance, and thermal properties required for the final product.

5. Main process problems of 3D Metal Printing:

While 3D metal printing is a powerful manufacturing technology, there are several process problems that can arise during the printing process. Here are some of the main process problems of 3D metal printing:

1. Warping and distortion: Metal parts can warp or distort during the printing process due to uneven cooling or stress build-up. This can result in parts that are out of tolerance or do not meet the required specifications.

2. Poor surface finish: The surface finish of metal parts produced using 3D metal printing can be rough or uneven, which may require additional post-processing to achieve the desired surface finish.

3. Porosity: Metal parts produced using 3D metal printing may exhibit porosity or voids in the material due to insufficient melting or poor powder quality.

4. Cracking and delamination: Metal parts may experience cracking or delamination during the printing process due to thermal stresses or poor bonding between layers.

5. Inadequate support structures: Support structures are required during the printing process to prevent metal parts from collapsing or warping. If support structures are not properly designed or positioned, it can lead to failed prints or poor surface finish.

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6. Powder contamination: Metal powders can become contaminated during the printing process, leading to inconsistencies in the final product or even failed prints.

7. Inconsistent material properties: Metal parts produced using 3D metal printing may exhibit inconsistent material properties due to variations in the printing process or powder quality.

6. Applications of 3D Metal Printing:

Numerous industries use 3D metal printing for a variety of purposes. The following are some of the key uses for 3D metal printing:

1. Aerospace: 3D metal printing is used to produce complex, lightweight components for aerospace applications, such as turbine blades, brackets, and heat exchangers.

2. Medical: 3D metal printing is used to produce custom medical implants and surgical tools, such as hip and knee replacements, dental implants, and bone scaffolds.

3. Automotive: 3D metal printing is used to produce lightweight, high-strength parts for the automotive industry, such as engine parts, suspension components, and chassis components.

4. Tooling: 3D metal printing is used to produce custom tooling and moulds for various industries, such as injection moulding, die casting, and metal stamping.

5. Jewellery: 3D metal printing is used to produce complex and intricate jewellery designs, such as custom wedding rings and bracelets.

6. Architecture: 3D metal printing is used to produce complex and unique architectural components, such as facades, columns, and sculptures.

7. Military and defence: 3D metal printing is used to produce lightweight, high-strength parts for military and defence applications, such as weapons components, protective gear, and unmanned aerial vehicles.

7. Advantages and disadvantages of 3d Metal Printing:

1. Advantages of 3D metal printing:

   1. Design freedom: 3D metal printing allows for the creation of complex and intricate designs that are difficult or impossible to achieve using traditional manufacturing methods.

   2. Customization: 3D metal printing allows for the creation of customized and personalized parts to meet specific needs and requirements.

   3. Reduced waste: 3D metal printing produces parts with minimal waste, reducing material and energy usage compared to traditional manufacturing methods.

   4. Rapid prototyping: 3D metal printing allows for the rapid production of prototypes and small batches of parts, reducing time to market and development costs.

   5. Reduced tooling costs: 3D metal printing eliminates the need for costly tooling and moulds, reducing the upfront costs of production.

   6. Material flexibility: 3D metal printing can use a wide range of metal materials, allowing for the production of parts with specific material properties.

Disadvantages of 3D metal printing:

1. High cost: 3D metal printing is currently more expensive than traditional manufacturing methods due to the high cost of equipment, materials, and post- processing.

2. Limited production volume: 3D metal printing is currently best suited for the production of small volumes of parts, making it less cost-effective for large- scale production.

3. Post-processing requirements: 3D metal printed parts often require post-processing, such as polishing or heat treatment, to achieve the desired surface finish and material properties.

4. Surface finish limitations: 3D metal printed parts may have a rough or uneven surface finish, which may require additional post-processing or finishing.

5. Material quality limitations: The quality and consistency of 3D metal printed parts may be impacted by variations in the metal powder, printing parameters, or other factors, leading to inconsistent material

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Conclusions:

3D metal printing has revolutionized the way we approach manufacturing and production. It offers unparalleled design freedom, customization, and reduced waste compared to traditional manufacturing methods. 3D metal printing has proven to be a valuable tool in various industries such as aerospace, medical, automotive, and tooling.

However, the high cost, limited production volume, and post-processing requirements of 3D metal printing must be considered before choosing this manufacturing method. Additionally, ongoing research and development are needed to improve the consistency and quality of 3D metal printed parts.

Despite these challenges, the potential benefits of 3D metal printing are significant, and this technology will undoubtedly continue to play an important role in the future of manufacturing. As 3D metal printing becomes more accessible and affordable, it has the potential to transform the way we design and produce complex metal components, enabling us to create innovative and customized solutions for a wide range of applications.

References:

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[2] Electron beam 2016, Wikipedia, https://en.wikipedia.org/wiki/Electron_beam_freeform_fabric ation

[3] Herderick, E., 2011, Additive Manufacturing of Metals: A Review, Materials Science and Technology (MS&T) 2011,October 16-20, 2011, Columbus, Ohio

[4] Morris, G. 2014, Additive Manufacturing at GE www.gecapital.com/webinar-assets/pdf/3dprinting- capital.pdf

[5] Swift, K.G. and Booker, J. D, 2013, Manufacturing Process Selection Handbook Page No. 234 & 235 Chapter 8, Elsevier Ltd, 2013

[6] International Journal and Magazine of Engineering, technology, Management and Research Paper on Structural Static Analysis of Knuckle joint by P Ganesh and J. Bala Bhaskara Rao, Department of Mechanical Engineering SISTAM. College JNTUK, India.

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