Using a computer-generated design, 3D printing, sometimes referred to as additive manufacturing, is a technique for building three-dimensional objects layer by layer. A 3D item is produced by the additive method of 3D printing, which involves building up layers of material. A final design is cut from a larger block of material in subtractive manufacturing techniques, which is the opposite of this. The result is minimal material waste due to 3D printing. Rapid prototyping is made possible by 3D printing because technology is so well suited to the manufacture of intricate, custom goods. Thermoplastics like acrylonitrile butadiene styrene (ABS), metals (including powders), resins, and ceramics are just a few of the materials that can be used in 3D printing.

History of 3D Printing

Hideo Kodama of the Nagoya Municipal Industrial Research Institute created the first 3D printing production machinery when he created two additive techniques for creating 3D models. Hideo Kodama's pioneering work in laser-cured resin rapid prototyping was finished in 1981, building on Ralf Baker's 1920s work for creating decorative objects (patent US423647A). With the launch of stereolithography in 1984, his innovation was improved throughout the following three decades. In 1987, Chuck Hull of 3D Systems created the first 3D printer using the stereolithography technique. Following this, innovations included selective laser melting and sintering, among others. Other pricey 3D printing systems were created in the 1990s and 2000s, but their prices drastically decreased as their patents expired in 2009, making the technology accessible to more people.

3D Printing Technologies

There are three broad types of 3D printing technology; sintering, melting, and stereolithography.

Sintering is a technology where the material is heated, but not to the point of melting, to create high-resolution items. Metal powder is used for direct metal laser sintering while thermoplastic powders are used for selective laser sintering.

Melting methods of 3D printing include powder bed fusion, electron beam melting and direct energy deposition, these use lasers, electric arcs, or electron beams to print objects by melting the materials together at high temperatures.

Stereolithography utilizes photopolymerization to create parts. This technology uses the correct light source to interact with the material selectively to cure and solidify a cross-section of the object in thin layers.

3D Printing Processes

Binder Jetting

Binder jetting involves the application of a small layer of powered material, such as metal, polymer sand, or ceramic, onto the build platform. Next, print heads apply drops of glue to bind the material's particles together. Layer by layer, the part is constructed using this method, and afterward, post-processing may be required to complete the build. Metal pieces can be thermally sintered or penetrated with a metal that has a low melting point, like bronze, as examples of post-processing, while ceramic or full-color polymer parts can be saturated with cyanoacrylate adhesive. Large-scale ceramic molds, full-color prototypes, and 3D metal printing are just a few of the uses for binder jetting.

Direct Energy Deposition

In direct energy deposition, wire or powder feedstock is fused as it is deposited using focused thermal energy such as an electric arc, laser, or electron beam. To build a layer, the procedure is traversed horizontally, and to build a portion, layers are piled vertically. Metals, ceramics, and polymers are just a few of the materials that can be employed with this method.

Material Extrusion

A spool of filament is fed into an extrusion head with a heated nozzle in the process of material extrusion, also known as fused deposition modeling (FDM). The build platform then lowers in preparation for the subsequent layer after the extrusion head heats, softens, and deposits the heated material at predetermined positions. Short lead times and cost-effectiveness come at a cost of low dimensional accuracy and frequent post-processing to achieve a smooth finish. Additionally, this method often results in anisotropic parts, which are weaker in one direction and unsuitable for demanding applications.

Material Jetting

Comparable to inkjet printing, material jetting involves depositing layers of liquid material from one or more print heads rather than ink on a page. The layers are then allowed to cure before the procedure is repeated for the following layer. Although support structures are needed for material jetting, they can be created of a water-soluble material that can be removed once the build is finished. The most expensive 3D printing technique, material jetting, is a precise procedure, but the items tend to be fragile and lose quality over time. However, using this method makes it possible to produce parts in a range of materials in full color.

Powder Bed Fusion

In the process known as powder bed fusion (PBF), heat energy (such as a laser or electron beam) selectively melts portions of a powder bed to produce layers, which are then layered upon one another to make a part. PDF includes both sintering and melting processes, it should be noted. All powder bed systems operate in essentially the same way: a recoating blade or roller applies a thin layer of powder to the build platform; next, a heat source scans the powder bed surface, selectively heating the particles to cause them to bind.

Sheet Lamination

Laminated object manufacture (LOM) and ultrasonic additive manufacturing are two distinct techniques for sheet lamination (UAM). UAM attaches thin sheets of metal using ultrasonic welding, whereas LOM uses alternate layers of material and glue to form objects with a pleasing appearance. Aluminum, stainless steel, and titanium may all be processed with UAM, which uses low temperatures and little energy.

VAT Photopolymerization

The two methods of VAT photopolymerization are stereolithography (SLA) and digital light processing (DLP). Both of these procedures employ light to selectively cure the liquid resin in a vat, building pieces one at a time. While DLP flashes a single picture of each entire layer onto the surface of the vat, SLA uses a single-point laser or UV source for the curing process. To increase the robustness of the pieces, parts must first be cleansed of extra resin after printing and then subjected to a light source. Additionally, any support structures must be taken out. To produce a finish of greater quality, more post-processing can be applied.

These procedures may produce precise details with a smooth finish, making them ideal for prototype production and items with a high degree of dimensional precision. The parts are less suited for use in functional prototypes, though, as they are more brittle than those produced using fused deposition modeling (FDM). Additionally, these components should not be used outside because exposure to UV light from the sun could cause the color and mechanical qualities to degrade. The necessary support structures could potentially leave imperfections that call for post-processing.

How Long Does 3D Printing Take?

The size of the item and the printing settings are just two of the variables that affect printing time. When estimating printing time, the finished part's quality is particularly crucial because more time is required to make higher-quality items. The time required for 3D printing can range from a few minutes to several hours or even days; key considerations are speed, resolution, and material volume.