Before a manufacturing company can mass produce a new product, it must first build a prototype. This can be a long process, but Phoenix 3D Printing makes it possible to do so more quickly.
3D Printers can be used in almost every industry. In this article we will look at the different types of printers, their pros and cons.
1. Fused Deposition Modelling (FDM)
Fused deposition modelling is the most popular 3D printing technology and is often the first type of printing that people try. Also known as Fused Filament Fabrication (FFF), it utilises continuous thermoplastic filament in a thread form to create 3D objects and structures. The print head heats the filament and then selectively deposits it onto a build platform layer by layer, forming the final part. The build platform moves down after each layer and the process repeats until the object is complete.
Unlike SLS, where liquid resin is used to form solid layers, FDM uses thermoplastic polymers such as ABS, PLA or Nylon which are melted and extruded in the semi-solid state. These materials can be easily sourced and the technology is relatively inexpensive compared to its counterparts, making it ideal for design prototyping and low-volume end-use parts.
The quality of the prints produced by FDM is not as high as other technologies and the parts are often prone to noticeable layer lines. As a result, post-processing is often required to produce a good finish on the part. Furthermore, the FDM process is anisotropic which means that the parts are stronger in one direction than in another. This can make the printing of some complex geometries challenging.
The fact that FDM prints require support structures to keep the part upright during printing means that these supports have to be printed as well, which increases the overall cost of the print. It is therefore important to design the part in such a way that the support structures can be printed quickly and easily. Dissolvable support structures are available, but they can be difficult to remove.
2. Stereolithography (SLA)
Known for industry-leading part accuracy, detail resolution and smooth surface finish, SLA 3D printing is often employed for engineering and medical applications. However, its versatility also means that it can be used to produce a wide range of end-use products with a variety of materials, including high-performance resins.
Like DLP, SLA uses UV light to draw patterns on the surface of liquid photopolymer resins to build up objects layer by layer. To create a printed object, the digital file is sliced into sections and the SLA machine draws each section on the surface of the liquid resin using an ultraviolet laser beam. After the laser has drawn a complete layer, the platform moves down and the laser recoating bar images the next layer of resin onto the surface of the previous layer. This is repeated until the entire print has been constructed.
Once the print is completed, it is rinsed in solvent to remove any excess uncured resin and then subjected to UV light to ensure it has fully cured and hardened. If required, support structures can be added to prevent sagging and collapsing during the process, but they are typically removed after printing.
SLA printers come with a wide range of liquid resins to suit different applications, from standard clear plastics for aesthetic purposes to castable or dental resins that have specific physical properties for use in end-use parts. Industrial SLA systems offer a wider selection of resins than desktop systems, giving designers greater control over the mechanical strength of their prints.
The accessibility of SLA printers raises concerns about intellectual property infringement, enabling the replication and distribution of protected designs without proper licensing or permissions. While this can have advantages, it is important to balance innovation with respecting the rights of creators.
3. Multi Jet Fusion (MJF)
Multi Jet Fusion (MJF) is a 3D printing process from HP that delivers functional prototypes and end-use parts for manufacturing. It provides quality nylon parts with fine feature resolution and consistent isotropic mechanical properties. It is ideal for parts that need complex, organic geometries and a fast build time to meet demanding production timelines.
This industrial AM process is similar to FDM and SLS in that it builds components layer-by-layer, but differs by utilizing a continuous supply of powdered materials rather than multiple extruders. This allows the printer to recycle unused powder, and reduces waste to 80% compared to other additive processes. MJF also eliminates the need for support structures, shortening print times and eliminating laborious post-processing. The resulting parts are more functional with no marks left by supports, and can be dyed or coated in primer to improve cosmetic appearance and functionality.
Currently, MJF prints in a polyamide (PA12) material that is water-resistant and chemical resistant, and can be used for both tensile and flexural strength. It is a great choice for engineering-grade parts that require balanced mechanical properties, a high elongation to flex ratio, and excellent chemical resistance.
Unlike injection molding, which requires costly tooling, MJF offers a cost-effective alternative for low volume production. Typical applications include jigs and fixtures, electronic component housings, mechanical assemblies, and enclosures. Protolabs is exploring new, advanced MJF materials and capabilities to expand the technology’s range of uses. These include glass-filled nylon, flame-retardant PA12, and elastomers. Ultimately, the ability to deliver durable, functional parts in a quick turnaround helps to make MJF one of the most promising AM technologies for realizing Industry 4.0. Its rapid build time, dimensional accuracy and surface finish, and the ease of post-processing make it a valuable tool for prototyping and small series production.
4. Direct Metal Laser Sintering (DMLS)
DMLS is a 3D printing technique that utilizes metallic powders to manufacture metal components in layer-by-layer fashion. The process requires meticulous engineering and high-grade materials to ensure that the quality of the final product reaches industrial standards.
The process starts with a digital blueprint that is a three-dimensional model created using CAD software, whose details dictate the precise specifications of the finished part. The model is then sliced into thousands of horizontal layers. A powerful laser beam then fuses the metallic powder evenly deposited on the work platform in selected areas, which melts and bonds to the previous layer to form a layer of metal. The laser beam then moves to the next area, and so on, fusing the powder to create a solid structure that gradually forms the desired part.
Once the layer is complete, the platform lowers a little to allow a recoater blade to apply another thin layer of powder. The laser beam then scans the surface of this layer, melting and bonding the pulverous material to the existing layer. The recoater blade then applies the next layer of powder, and so on, until the part is fully built.
Due to the precision of DMLS, it is ideal for producing metal parts that need to have tight tolerances or complex geometry. It also enables quick production of functional prototypes that can be used for testing purposes. DMLS parts typically have satisfactory mechanical properties, with values comparable to those of conventionally-produced parts.
However, the DMLS process is not without its limitations. The initial investment for the equipment and specialized metal powders is very high. Furthermore, the process can only be used on a limited range of alloys and metals, which limits design possibilities. Therefore, additional processing steps like solution annealing and hot isostatic processing are usually required to improve the performance of the finished part.
5. Material Jetting
Material jetting, also known as MJ 3D printing, is an additive manufacturing process that creates layered parts by solidifying hundreds of photopolymer microdroplets using a UV light source. It offers high precision, smooth surfaces and a wide range of materials. This makes it ideal for prototyping and end-use components with highly intricate geometries.
Similar to binder jetting, the material jetting process lays powdered materials on top of each other and is capable of dispensing multiple different colors of material. The print head is able to change the viscosity of the material being deposited, allowing for multi-material and full color prints. The print process can also be adjusted to change the layer thickness, which affects the resolution and surface finish of the final part.
MJ has many applications in healthcare, such as the ability to produce highly detailed anatomical models for surgical planning and prosthetics. It is also used in the automotive and aerospace industries to make prototypes and components that require high-fidelity detailing and structural integrity. It can even be used to produce functional end-use components in small volume, such as air ducts and dashboards.
One of the key differences between MJ and other 3D printing technologies is that, unlike FDM printing, material jetting requires the use of a support structure to hold up overhanging features during the build process. MJ supports are printed in a secondary, dissolvable material that can be easily removed after the print has been dissolved with pressurized water or immersed in an ultrasonic bath. This helps to eliminate the need for harsh post-processing and results in a smooth surface that shows no indication of the original support structures. However, this additional step can add to the overall time and cost of production.