Additive manufacturing (AM) is also known as 3D printing. It is a transformational approach to industrial production that uses a computer-controlled process to generate three-dimensional objects through the process of adding materials layer-by-layer.
- 1 How Does Additive Manufacturing Work?
- 2 Additive Manufacturing Process
- 3 Who Invented AM?
- 4 What are the Advantages of Using Additive Manufacturing?
- 5 How Long Does the Process Take?
- 6 What Materials can be used in Additive Manufacturing?
- 7 Where is AM used?
How Does Additive Manufacturing Work?
Additive manufacturing works by using a computer-aided design (CAD) or 3D object scanner that directs hardware to place material, layer-by-layer to create precise geometric shapes. This is different than traditional manufacturing methods that use milling, machining, shaping, carving or various other methods to remove excess material.
Additive Manufacturing Process
There are several different forms of additive manufacturing processes which include:
Binder jetting uses a 3D printer style head that lays down and moves on the x, y, and z axes in order to alternate layers of powdered material. The powdered particles are bound together using droplets from the liquid binder which are propelled out of the printer head. When finished, the part is cured in an oven to get rid of any excess binding agents.
Directed Energy Deposition
Directed energy deposition uses an electron beam gun or a laser that is mounted on a multi-axis arm. Material (powder or wire form) is deposited from the nozzle onto the surface of the object. Then, the laser melts the material. Additional material is added layer-by-layer and hardens creating the new piece. This additive manufacturing technique can be used with a wide range of material including polymer, metal, and ceramic.
This is the most recognized additive manufacturing processes. During material extrusion spooled polymers are pushed through a heated nozzle mounted on a moveable arm. This continuous stream of heated polymers is deposited layer-by-layer. The layers stay formed together through temperature control or chemical bonding agents to create the 3D object.
Powder Bed Fusion
The power bed fusion additive manufacturing process uses the following printing techniques: direct metal laser sintering (DMLS), direct metal laser melting (DMLM), selective heat sintering (SHS), electron beam melting (EBM), and selective laser sintering (SLS). Powder bed fusion works by using either a laser, thermal print head, or electron beam to melt and fuse thin layers of material powder together in a three-dimensional space. Once the process is finished, loose powder material is removed.
This process involves sheets of material bonded together layer-by-layer to form a single object that is then cut into a 3D piece.
Sheet Lamination can be divided into two separate categories:
- Ultrasonic additive manufacturing (UAM) uses sheets or ribbons of metal and binds them together through the use of ultrasonic welding. Additional CNC machining and removal of excess metal is frequently needed during the welding process. This process requires little energy and is a low-temperature process and can be used with different metals such as stainless steel, copper, steel, titanium and aluminum.
- Laminated object manufacturing (LOM) also uses a layer-by-layer approach but uses paper as material and adhesive instead of welding. Each layer of material is bonded with glue on top of the prior one until the component is finished. This process is frequently used for visual and aesthetic models and should not be used for structural purposes.
Vat photopolymerization uses a vat of liquid photopolymer resin to construct an object layer-by-layer. The process involves mirrors precisely directing the ultraviolet (UV) light where to go. When the photopolymer molecules are exposed to certain wavelengths of light, they rapidly bind together to create a solid form. This additive manufacturing process is fast and extremely accurate.
Wire Arc Additive Manufacturing
This additive manufacturing process uses an arc welding process to 3D print objects. This process is controlled by a robotic arm that follows a predetermined path. The object is built upon a base plate and the object can be cut when finished. This process can work with a wide range of metals such as stainless steel, nickel-based alloys, titanium alloys, and aluminum alloys as long as they are in wire form.
Additive Manufacturing Technologies
Additive Manufacturing Technologies can be divided into three broad types:
- Sintering is where the material is heated, but not to the point of being liquefied, in order to create a multifaceted, high-resolution object. Selective laser sintering uses a laser on thermoplastic powder in order to get the molecules to adhere together. Direct metal laser sintering does the same thing as selective laser sintering except uses a metal powder as the material.
- Stereolithography uses a process known as photopolymerization. This process involves a UV laser that is directed into a vat of photopolymer resin in order to build torque-resistant ceramic parts that are able to withstand extreme temperatures.
- Melting is where the additional manufacturing technology such as direct laser sintering, completely melts the material. A laser or electron beam can be used to melt the layers of powder.
Who Invented AM?
Hideo Kodama, of Nagoya Municipal Industrial Research Institute, was the first to invent the single-beam laser cutting. He also invented basic 3D printing techniques such as stereolithography and photopolymerization.
What are the Advantages of Using Additive Manufacturing?
- Complex geometries. The ability for complex geometries is one of the biggest advantages of additive manufacturing because AM enables the development of bespoke parts with multifaceted geometries.
- Little material wasted. This makes AM more cost-effective saving businesses money.
- Rapid prototyping. Design alterations can be completed quickly and efficiently because of the digital process.
- Improved strength and durability. Parts that were previously assembled from multiple pieces are fabricated into a single object.
- Unique objects and replacement pieces. AM is able to create unique objects and replacement segments where the original pieces are no longer produced.
- Easy to change or revise product. AM enables designers to produce multiple versions of a single design in a cost-effective manner.
How Long Does the Process Take?
The length of time can vary from a couple minutes to a few hours or even days. The amount of time it takes to print involves a lot of different factors.
First, the size of the piece and the settings involved for printing effect the length of time the process can take. The larger the piece the longer it will take.
Also, the quality of the completed parts is important in order to figure out printing time because higher-quality pieces with better resolution will take longer to create.
Lastly, the speed varies according to the additive manufacturing technology used. AM includes a variety of technologies and methods that don’t have the same printing speeds. For example, laser power, print nozzle’s temperature, layer thickness, and filament thickness are all important factors that determine the speed of AM technologies.
What Materials can be used in Additive Manufacturing?
There are a lot of different materials that can be used for additive manufacturing which include:
- Calcium phosphate
- Bio-inks fabricates from stem cells
- Tricalcium phosphate
- Powdered glass
Metals and Metal Alloys
- Stainless steel
- Polycarbonate (PC)
- Acrylonitrile butadiene styrene (ABS)
- Water-soluble polyvinyl alcohol (PVA)
- Polylactic acid (PLA)
Where is AM used?
Additive manufacturing can be found in a variety of products across different industries such as:
Additive manufacturing’s ability to convert raw materials into complex 3D forms without the need for complex tools makes it advantageous to the aerospace industries. AM enables complex designs, materials to be mixed, and energy efficiency in order to produce lightweight parts enabling designers to save time and experience significant cost savings. AM is used in the aerospace industry to create hinges, brackets, interior components, and lightweight fuselage and airframe designs in order to improve fuel efficiency. It can also be found in turbine blades.
Additive manufacturing has enabled the automotive industry to create lighter, stronger, and safer products. They are able to develop more robust designs and use rapid prototyping to experience reduced lead times and a reduction in costs. One way the automotive industry uses AM is to create accurate models that enable the designer’s intentions to be clearly communicated to show the overall form of a concept. Further, AM enables full testing and validation of prototype performance. AM can be found in various finished products for a vehicle such as in battery covers, air condition ducts, and front bumpers.
In the medical industry, additive manufacturing has helped solve medical issues resulting in a huge benefit to humanity. AM plays a major role in product development in the healthcare industry. It helps reduce the cost of production, development, cycle time, and enables rapid product development. AM also makes operations faster, cost-efficient, and more accurate than manual processes. A few items that AM is used to create are dental prosthetics such as crowns, repair bone defects through customized implants, and custom fit masks.