3D printing technologies are developed year by year. Mainly 5 technologies use in the 3D printing process. Some are used with changing the small mechanism. But it affects the process heavily. In summary, there are 10 sub-technologies mainly use in 3D printing. So let’s see what are those technologies and compared them with others.
Extrusion Deposition Modeling (FDM)
This is the common type of 3D printing technology that we are using today. Normally we name this as an FDM stated by Fused Deposition Modeling. In this printing, technology filament is used as extrusion, and it is heated by the nozzle and build the 3D model layer by layer bottom to the top of the bed.
This is a clean technology and widely used all over the world with many filaments. This method was invented By Stratasys founder Scott Crump.
In this technology, you should do
- Pre-Processing: Clice software is used to slice the 3D model and then estimate the material and time according to the infill patterens, supports, orientation and many necessary parameteres for the G-Code genaration
- Production: The 3D printer heats the thermoplastic to a semi-liquid state and deposits it in ultra-fine beads along the extrusion path. When support is need for the printed 3D model it can build by another filaments.
- Post-Processing: The user breaks away support material or dissolves
it in detergent and water, and the part is ready to use
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Most of the 3D printers are FDM for the domestic as well as industrial. These kinds of 3D printers are named Extrusion Deposition.
This is name as Fused Filament Fabrication (FFF), Plastic Jet Printing (PJP), Direct Ink Writing (DIW)
Stereolithography (SLA) was invented in 1986 by Charles “Chuck” Hull, the founder of 3D Systems. This technology is really accurate rather than FDM.
SLA printers build accurate parts using the 3D CAD data without tooling by converting the liquid materials and composites into solid cross-sections, layer by layer, using an ultraviolet laser.
The bed then lowers, the part is coated with a new layer of resin, and the next layer is built on top of the others until the part is finished. When a part is complete, it is cleaned in a solvent solution to remove the wet resin remaining on the part surface. Afterward, the part is put in a UV oven to complete the curing process.
SLA is a high accuracy, its accuracy is less than 0.05mm, and it provides the smoothest surface finish of any additive manufacturing process. SLA is used for highly precise casting patterns such as injection molds. It provides the faithful final output models.
ABS or polypropylene is used as a printing material.
Digital Light Processing (DLP)
DLP is used for the rapid prototyping process. It is a form of stereolithography that is used in rapid prototyping services.
DLP uses a projector to light the essential points to be cured the resins. When the resin layer is open to the light, it will harden, and then the 3D printer will create another layer on the previous layer. This process happens all over the process, and finally, it provides a high-resolution 3D model.
The finished 3D model was subjected to remove the support material, chemical bath and then UV curing.
DLP 3D printers use photosensitive resin plastic as a material. The average cost of photosensitive resin will be $80 – $200
Unlike DLP, there is no soluble supports. Supports and models are creating together with the same material. Hence we need to use optional ways to remove the supports carefully.
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Electron Beam Melting (EBM)
The electron beam is used for melting the material instead of the laser beam. The machine distributes the layer of metal powder onto the build platform. The electron beam is aimed at the relevant places, and then the powder is melted due to the heat.
When the layer is melted bed moves down, and a new metal powder layer is laid on the bed. This process is repeated during the 3D printing process.
In this process, we can have 99% good mechanical properties. Compared to laser melting, EBM produces less thermal stress, and due to this, it required fewer support structures that will save time.
EBM is a little bit slow and expensive because it works with limited types of metals.
- Maximal Build Envelope: 350x350x380mm (1.15×1.15×1.25feet)
- Minimum Feature Size: 0.1mm
- Typical Tolerance: +/- 0.2mm (can be improved through machining)
- Minimum Layer Thickness: 0.05mm 45
- Typical Surface Finish: 20.3 – 25.4microns RA (can be improved through post processing)
- Density: Up to 99.9%
Selective Laser Melting (SLM)
Selective Laser Melting (SLM) provides a laser beam to melt the metal powder. When the laid metal layer is melted by the laser, and then another layer is melted on the bed. This will happen during the process. The parts are built up layer by layer with relevant supports.
SLM requires support structures because laser melting produces more heating. It can prevent wrapping and reduce thermal stresses.
The surface is not much finished, and tolerance is limited.
Accuracy is +/-0.05-0.2mm (+/- 0.1-0.2%).
The minimum layer thickness is 0.03mm.
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Selective Laser Sintering (SLS)
Above process, we used metal powder for the printing material. But in SLS we use plastic powder instead of metal powder. The laser is used for melting the plastic powder on the platform.
SLS does not require any supports structure to the model. The build parts are sustained by the loose plastic powder. Due to this, the entire part can be made with several parts, including stacking and pyramiding.
- Maximal Build Envelope: 550x550x750mm (1.8×1.8×2.5feet)
- Minimum Feature Size: 0.15mm
- Typical Tolerance: +/-0.25mm (can be improved through post-processing)
- Minimum Layer Thickness: 0.1mm
Selective Heat Sintering (SHS)
In this process, the plastic powder layer is heated by the less power heated beam. Considering the SLS, SHS has a less intense thermal printhead instead of the laser beam in SLS.
Therefore it is a cheaper solution to make the 3D printer a desktop size.
Direct Metal Sintering (DMS)
DMS is used for most alloys. The DML uses an Yb (Ytterbium) fiber laser fired into a bed of powdered metal, aiming the laser automatically at points in space defined by a 3D model, melting or rather, welding the material together to create a solid structure.
Laminated Object Manufacturing (LOM)
In this process paper sheet is laminated with adhesive on one side.
- Layer fabrication starts with sheet being adhered to substrate with the heated roller
- Then laser traces the out line of the layer.
- Non-part areas are cross-hatched to facilitate removal of waste material
- When the laser cutting is finished the paltform move down and sheet material roll in to new position
- Once new material is position the platform moves back and upto layer below it previos position.
- Process is repeated.
- The object is heated in the final stage.
Electron Beam Freeform Fabrication (EBF3)
A focused electron beam in a vacuum environment ( Vaccum chamber) to create a molten pool on the metallic substrate. Aluminum, nickel, steel, or titanium are
melted one layer at a time until the part is complete. This is developed by the NASA research center.
What is the Best 3D Printing Technology?
The best 3D printing technology is FDM. It is really user-friendly and considerably accurate for making a 3D model domestic and industrially. SLA, DLP, EBM, SLM, SHS, DMS are really expensive and not user-friendly.