Through computer programmed deposition of material in successive layers to create a three-dimensional object.
4D printing adds the dimension of transformation over time.
Stereolithography for 3D printing —-
stereolithography apparatus, optical fabrication, photo-solidification, or resin printing) is a form of 3D printing technology used for creating models, prototypes, patterns and production parts in a layer by layer fashion using photopolymerization, a process by which light causes chains of molecules to link, forming polymers.
Stereolithography for 4D printing——
4D printing is fundamentally based in stereolithography, where in most cases ultraviolet light is used to cure the layered materials after the printing process has completed.
Most 4D printing systems utilize a network of fibers that vary in size and material properties. 4D printed components can be designed on the macro scale as well as the micro scale.
Hydro-reactive Polymers/Hydrogels for 4D printing—–
Skylar Tibbits is the director of the Self-Assembly Lab at MIT and worked with the Stratasys Materials Group to produce a composite polymer composed of highly hydrophilic elements and non-active, rigid elements. The unique properties of these two disparate elements allowed up to 150% swelling of certain parts of the printed chain in water, while the rigid elements set structure and angle constraints for the transformed chain. Tibbits et al. produced a chain that would spell “MIT” when submerged in water and another chain that would morph into a wireframe cube when subjected to the same conditions.
Cellulose Composites for 3D printing-———-
Cellulose-based material that could be responsive to humidity. Wood composite materials that change shape based on their printed grain direction and anisotropic swelling when water is absorbed. This work is 3D printed and studied on the macro scale rather than micro scale, with layer heights at fractions of millimetres rather than microns.
Thermo-reactive Polymers/Hydrogels for 4D printing—–
Thermo-responsive material. This new type of 4D printed hydrogel is more mechanically robust than other thermally actuating hydrogels and shows potential in applications such as self-assembling structures, medical technology, soft robotics, and sensor technology. A fluid controlling smart valve printed from this material was designed to close when touching hot water and open when touching cold water.
Digital Shape-Memory Polymers for 3D printing-———
SMPs are able to recover their original shape from a deformed shape under certain circumstances, such as when exposed to a temperature for a period of time. Depending on the polymer, there may be a variety of configurations that the material may take in a number of temperature conditions. Digital SMPs utilize 3D printing technology to precisely engineer the placement, geometry, and mixing and curing ratios of SMPs with differing properties, such as glass transition or crystal-melt transition temperatures.
Stress Relaxation for 4D printing———-
4D printing is a process in which a material assembly is created under stress that becomes “stored” within the material. This stress can later be released, causing an overall material shape change.
Thermal Photo-reactive Polymers for 4D printing-——–
This type of polymeric actuation can be described as photo-induced stress relaxation.
CAD, 3D scanner
Before printing a 3D printing model from an STL file, it must be examined for an error. Most CAD applications produce errors in output STL files.
Repair fixes in the original model.
A 3D scanner is a device that analyses a real-world object or environment to collect data on its shape and possibly its appearance
G-code is a language in which people tell computerized machine tools how to make something. The “how” is defined by g-code instructions provided to a machine controller (industrial computer) that tells the motors where to move, how fast to move, and what path to follow.
Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics (and moderate-quality photographs) by repeatedly passing a laser beam back and forth over a negatively charged cylinder called a “drum” to define a differentially charged image. The drum then selectively collects electrically charged powdered ink toner, and transfers the image to paper, which is then heated in order to permanently fuse the text and/or imagery. As with digital photocopiers, laser printers employ a xerographic printing process.
Injection moulding Bre or Injection moulding Ame is a manufacturing process for producing parts by injecting material into a mould. Injection moulding can be performed with a host of materials mainly including metals, glasses, confections, and most commonly thermoplastic and thermosetting polymers. Material for the part is fed into a heated barrel, mixed, and forced into a mould cavity, where it cools and hardens to the configuration of the cavity