17 Sep Learn About 3D Printing in Ten Minutes
So you are a random net surfer that knows what a 3D printer is but you don’t really know how it works? You are just getting started and you know the basics but different types of printers confuse you? Here’s a short guide about all the technologies of 3D printing.
3D printing is a production process, the result of which is a three-dimensional object created by the successive placement of layers of material.
This process is called additive because the object is made ab ovo, in contrast to the abstract processes in which the material is further processed by drilling, cutting, and similar processes. These models are created using 3D printers of different types and sizes. Printers create three-dimensional models by obtaining data from CAD programs (Computer-Aided Design Programs), or they can replicate them using 3D scanners.
Due to its wide range of possibilities of making three-dimensional objects, 3D printing is used not only in architecture but also in construction engineering, industrial design, for making jewelry, footwear, and clothing, in space programs, medicine, and dental medicine in which it reaches its peak through 3D printed organs and body parts.
In 1981 Hideo Kodama from the Nagoya Municipal Industrial Research Institute published his work, which introduced a functional photopolymer rapid prototyping system. It was possible to make a solid three-dimensional object of the layers so that each layer corresponded to a cross-section of the model.
In 1984, Charles W. Hull created the first 3D printer to use the stereolithography technique, in which 3D objects are created using digital data, in this case, photographs. A UV laser beam is sent to the liquid photopolymer container (a type of acrylic-based material) that instantly turns the exposed part into a solid piece of plastic in the shape of your three-dimensional model. With this revolutionary discovery, inventors were able to create and test their patents in a much shorter time.
In 1992, the first SLS printer was invented. It was able to emit laser beams into powder instead of liquid. In the first decade of the 21st century, 3D printing revolutionized medicine. It was possible to print organs using a person’s cells, with almost 100% probability for the body to accept the transplanted organ. The mid-2000s led to cheaper printers available to a wide public range. 3D printers became able to make their own identical replicas, and the technology was most accepted in the field of spacecraft.
3D PRINTING TECHNOLOGIES
The position of each of the layers of the future three-dimensional object is monitored on the cross-section of its model made in one of the CAD programs.
Monitoring is performed with a laser beam that accurately transcribes each cross-sectional layer onto a liquid of photopolymer resin that hardens under the influence of ultraviolet light and solidifies to the layer below it. After each applied layer, the SLA moving platform is moved from 0.05 to 0.15 mm, depending on the selected layer thickness, and a new layer of liquid is applied with a needle on which the laser will overwrite the next read layer.
The process requires the use of support elements that secure the object to the movable platform because it floats in a vessel filled with photopolymer resin. Upon completion of the three-dimensional object, these supporting elements are removed.
This process is closely related to an inkjet printer that uses tiny droplets that drip onto each other to create a 3D shape and then solidify with UV light.
Two materials are used in this process: a powder base and a liquid binder.
In the construction chamber, the powder is applied evenly in layers using a roller, and the liquid adhesive that spreads through the nozzles binds the powder particles into the shape of a programmed 3D object.
The finished object remains in the chamber along with the powder which is removed after printing and reused to print the next object.
The most commonly used technology in this process is Fused Deposition Modeling (FDM).
Plastic or a metal wire which is unwound from a coil and fed into an extrusion nozzle that regulates the flow of material. This nozzle can be moved horizontally and vertically using a numerically controlled mechanism that is directly controlled by a Computer-Aided Manufacturing (CAD) software package. By extruding the material through a heated nozzle, layers are formed which dry immediately after extrusion and the desired 3D object is obtained.
Two types of materials are most commonly used: ABS (Acrylonitrile butadiene styrene) and PLA (Polylactic acid), but it is possible to use the full range of other materials.
Powder Bed Fusion
The most commonly used technology in this process is Selective Laser Sintering (SLS) in which glass, plastic, metal, or ceramic particles are bonded to a mass that has the desired three-dimensional shape using a strong laser.
By scanning the cross-section generated from the 3D modeling program, the laser on the substrate selectively binds the powder material particles. After scanning each section, the substrate is lowered by the thickness of one layer to which the next layer will come, and the procedure will be repeated until the desired 3D object is formed. All the powder intact by the laser remains in place, serving as a rigid object, which does not require additional fixation as in SLS and SLA processes.
After printing is complete, the remaining powder is removed and used to make the next object.
The process involves a metal, paper, or polymer material that comes in the form of sheets that are bonded together by an external force. The metal sheets are connected in layers by ultrasonic welding, and then the CNC machine converts them into the correct shape. The sheets of paper are glued with a special glue and they are cut into regular shapes with precise blades.
Directed Energy Deposition
The process is most commonly used in the high-tech metal industry and high-speed manufacturing processes.
The 3D printing apparatus is attached to a multi-axis robotic arm that contains a nozzle and a power source. The nozzle precipitates metal powder or wire that the energy source, most often a laser, melts and turns into a solid object.