© Kati Lehtinen and FIRPA, 2014

# English term Definitions
1 Additive manufacturing Group of technologies, to produce objects from 3D model data by joining materials, usually layer upon layer, in an attempt to find more flexible and complex ways of manufacturing. ASTM standard defines seven categories for additive manufacturing.
Additive fabrication,
Additive processes,
Additive techniques,
Additive layer manufacturing,
Layer manufacturing,
Freeform fabrication,
Solid Freeform Fabrication (SFF),
3D printing
2 3D printing Fabrication of concept models through the deposition of a material with various simple and low-cost 3D printers. Originally the term has meant 3DP-method and office-friendly machines. Now, the term is also used synonymously with additive manufacturing.

3 ASTM International Formerly known as the American Society for Testing and Materials (ASTM).
A globally recognized leader in the development and delivery of international voluntary consensus standards.

4 GARPA Global Alliance of Rapid Prototyping Associations.
The forum which encourages to sharing of information related to additive manufacturing.

5 Rapid tooling 1) Quick and additive methods for direct tooling or prototype tooling. Resulting parts serve as the actual tools or tooling components, such as mold inserts, or tooling patterns.
2) Quick conventional methods for direct tooling or prototype tooling

6 Rapid prototyping Prototyping with additive manufacturing, in which prototypes and small series are iteratively used to verify the form, fit and functionality of objects within the product development process, before actual manufacturing begins.

7 Direct manufacturing The use of additive manufacturing to make final products directly, without tooling.
Rapid manufacturing,
Toolless manufacturing
8 Conformal cooling channel Additive manufacturing offers the capability to design and create optimized channels which conform the shape of tooling or insert, allowing coolant to pass through the mold in passages that remove heat evenly and fast from the mold or die. The positioning of traditionally machined straight-line channels is more limited.

9 Prototype Signifies various types of models with different purposes used in different phases of the product development. With additive manufacturing it is possible to create complex 3D representations which can demonstrate appearance, dimensions and functionality of the object. Due to this, only one polyvalent prototype is needed for concept verification.

10 Small series production Production in small number of units. The first small testing series of a new product can be called «  zero  » series.

11 Hybrid manufacturing The combination of additive manufacturing and conventional CNC-machining in the automated manufacturing process.

12 Conventional manufacturing Covers subtractive manufacturing and forming technics.
Conventional machining,
Traditional machining
13 Subtractive manufacturing Conventional manufacturing which includes methods such as multi-axis milling and turning, EDM (Electrical Discharge Machining), grinding, laser cutting, drilling, and micro-machining, to remove material from the object.

14 Forming technics Traditional methods such as molding (i.e., injection molding and die casting), rolling, pulling, extruding, and compressing the material during the process.

15 Tool, tooling Mold, die, or other device used in various manufacturing processes such as plastic injection molding, vacuum casting, die casting, blow molding, thermoforming, sheet metal stamping, hydroforming, forging, and composite layup tooling, machining, and assembly fixtures. Molds and dies are the cavity frames for the manufactured piece.

16 Production tooling Tools, tooling used in serial product manufacturing

17 Prototype tooling Tools, tooling used to produce prototypes.
Bridge tooling,
Soft tooling
18 CAE Computer-Aided Engineering.
CAE includes CAD and CAM, and offers capabilities for engineering analysis and simulation, such as determining a design's robustness and performance.

19 CAD Computer-Aided Design.
CAD is used for drafting and modeling the design of real or virtual objects.

20 CAM Computer-Aided Manufacturing.
Typically refers to systems that use CAD model data to drive CNC machines, such as mills and lathes, to fabricate parts, molds, and dies.

21 CNC Computer Numerical Control.
Computerized control of machines for manufacturing. Machines that can be equipped with CNC capabilities include mills, lathes, grinders, and flame, laser, and water-jet cutters

22 Reverse engineering In additive manufacturing, refers to a method of creating a digital representation from a physical object, to define and document its shape, dimensions, and internal and external features, so that the gathered information enables the production of an equivalent physical object.

23 3D scanning Set of automated measuring methods that are used to determine the size and shape of an object in digital format, involving an optical device, such as laser, and sensors to provide data, and triangulation to calculate the xyz coordinates of the surface. Measurement data can also be obtained with photos from different angles.
3D digitizing
24 Triangulation A light which is projected onto the surface of an object, is observed from two points whose distance is known, which results to inferring the location of the intersection point on the surface of the object.

25 3D data The raw data, which contains large quantities of coordinate values known as point clouds produced by 3D-scanning systems.
Point cloud
26 3D CAD software tools The software tools for 3D CAD modeling to manipulate 3D data, to file conversions, or to produce compatible files for AM systems. The features cover resurfacing of CAD models and reparation of STL files, shelling, including grid structures, and creating supports. Some software tools serve as an interface between 3D measurement instruments.
AM software tools
27 Surface model Mathematical or digital representation of an object, not necessarily a closed volume, which is a combination of primitive planar or curved surfaces, Bezier B-spline or NURBS surfaces, or a mesh of polygons, such as triangles, which should approximate the exact shape of the model.

28 NURBS Non-Uniform Rational B-Splines.
NURBS surfaces give a mathematically accurate description to 3D CAD models.

29 Solid modeling Modeling software techniques to create virtual 3D models with geometric primitives such as cylinders and spheres, and features such as holes and slots, to define a closed, "water-tight" volume (with the information as to which parts are of material, and which are not).
3D modeling
30 Solid model Solid model is constructed virtually with modeling software, as an alternative to creating a shape with physical models made of wood or foam. Solid closed volume is an advantage over surface models.

31 3D CAD model 3D CAD model represents a 3D-printable object in usable faceted solid model format, which is either created with solid modeling or reconstructed from scanned 3D data.
3D model, 3D CAD representation
32 Lattice structures Complex internal structure of the designed object, often mathematically optimized, which adds the strength to the piece, which at the same time can be designed light and hollow to save material.

33 Support structure, anchor When the successive layers enlarge the form of the piece, the down-facing surfaces need the support structures to ensure the successful and usable fit and form of the piece. Supports start either directly from build platform or from the layers beyond the build surface. The anchors attach the piece to the base plate and give support from beneath. The type, material and parameters of the supports are determined within the design of the 3D model. The supports do not belong to the piece, although the material is often the same as the build material. Powder bed fusion with metals especially require supports, as well as material extrusion and vat polymerisation. In polymer powder bed fusion, no additional supports are usually needed as the unfused powder surrounding a part serves as a fixturing system,

34 IGES Initial Graphics Exchange Specification.
IGES is an industry standard format for exchanging CAD data between systems.

35 STEP Standard for the Exchange of Product Model Data.
STEP is a file format being used still in some AM machines and software to translate 3D model data. IGES led to STEP.

36 AMF Additive Manufacturing File.
New standardized file format for machine interface, which offers features that the STL format does not support. AMF is based on XML (an open standard markup language) and covers units, colors, textures, curved triangles, lattice structures, and functionally-graded materials. An AMF file is about half the size of a compressed STL file.

37 STL STL is the de facto standard interface for additive-manufacturing systems. STL originates from stereolithography. The triangular facets with diverse sizes and forms approximate the shape of an object in STL file, which contains a list of triangle vertices, and unit normals of the triangles. in binary and ASCII forms, ordered by the right-hand rule. Other 3D model attributes are excluded from the file.

38 Facet Typically a three- or four-sided polygon that mathematically represents an element of a 3D polygonal mesh surface or model. Triangular facets are used in STL files.

39 Binder jetting Process category in which a liquid bonding agent is selectively deposited to join powder materials, to form the object. The liquid bonding agent remains on the surface of the final object. Although the binder reacts at room temperature, it must cure in the powder bed for a few hours before the parts can be removed.

40 Directed energy deposition Process category in which focused thermal energy is used to fuse certain a point as the material is being deposited. In most cases, a laser is the source of the energy, and the material is a metal powder. The source of the energy and the nozzle can be either separate or integrated. Most directed energy deposition systems use a 4- or 5-axis motion system or a robotic arm to position the deposition head, so the build process is not limited to successive horizontal layers on parallel planes.

41 Material extrusion Process category in which melted material is selectively extruded onto previous build surface layers through a nozzle or an orifice, successively layer upon layer. The raw material is typically a filament of thermoplastic, but it can also be fluid mass which is dispensed through a pipeline, or from a material cartridge. Support structures are required for bottom surfaces and overhanging features. (Note! Extrusion is also a formative method for compressing the material, to produce the pipes with fixed profiles.)

42 Material jetting Process category in which droplets of build material are selectively deposited onto the build surface, as one or more print heads move across the build area. Example materials include photopolymer and wax, often kept in material cartridges.

43 Powder bed fusion Process category in which thermal energy selectively fuses regions of a powder bed. The powder surface is spread between the layers. Unfused powder supports the piece during the process.

44 Sheet lamination Process category in which sheets of material are bonded to form an object. Sheets can have one side which is adhesive and a heated roller laminates successive layers. Sheet materials are fed either from rolls or they are ready-cut sheets. The form of a 3D object is created by cutting the sheet layer.

45 Vat photopolymerization Process category in which visible or UV light is focused onto the build surface using DLP technology, thus liquid photopolymer in a vat is selectively cured by light-activated polymerization.

46 Cure, curing Curing means that the top surface of a liquid photopolymer in a vat becomes solid when it is scanned e.g. by guiding an ultraviolet laser through mirrors with DLP technology.
47 Additive systems Machines that join filament, liquid, powder, or sheet materials to form physical 3D objects using additive manufacturing.
AM machines,
AM systems
48 Industrial AM system Additive systems that are scaled to fulfill the industrial application specific requirements in regard to product quality.

49 3D printer Refers to a non-industrial additive system with low price, quality and capacity. Machine reliability and print quality, as well as the variety of materials, have increased considerably over the past couple of years.
Home-based 3D printer,
Home 3D printer,
Consumer 3D printer,
Low-end 3D printer.
50 Print head Material is deposited from the print head which is located above the build surface, on a fixed or robotic arm. In some systems print head also includes a separate source for focused thermal energy.
deposition head
51 Thermal print head Print head with the liquefier, the component in which solid material is heated and melted before deposition onto the building surface through a nozzle or orifice, where the material flow can be adjusted with a drive wheel.
Extrusion head
52 Focused thermal energy The energy source such as UV-laser, CO2-laser, electron beam, or plasma arch, which is focused onto the materials being deposited, in order to melt or cure the material, which becomes solid after cooling.

53 DLP Digital light processing.
Technology which uses lenses and micromirros, to manipulate laser beam. When coherent light propagates through lenses, it is intensified to focused thermal energy.

54 Material supply General term for different options of feeding material to AM systems, e.g. from a filament spool, material cartridge, vat or powder bed, depending on the device construction, and the nature of the material.

55 Filament spool The build material which is in the solid form of thread, wound on a cylinder.

56 Thermoplastics Thermoplastics have linear and branched chains of molecules, which have no chemical bindings. Thermoplastics retain their shock resistance, their processing is easy, and they can be repeatedly melted, cooled and hardened, and melted again, and therefore, they are suitable for complex designs. ABS and PVC are examples of thermoplastics.

57 Thermoset plastics Thermoset plastics are rigidly structured with lines of molecules which are heavily cross-linked. They are permanently "set" once they are formed and cannot be re-melted. The examples of thermoset plastics are acrylic, acrylate, and epoxy materials.

58 Material cartridge Changeable container, which includes the material which is used in additive manufacturing systems.

59 Powder bed The build chamber or container which is filled with powder, and can be moved up and down with the powder feed piston.
Powder feed supply
60 Vat «  Water-tight  » transparent tank or liquid feed supply in a build chamber.
Transparent tank
61 Material spreader The part of the AM machine that levels the powder or liquid surface between processing the layers.

62 Build surface The current surface layer on which the building of an object is occurring.

63 Build chamber Build chamber is a space in the additive system where the thermal energy process is controllable.

64 Inert gas Sensitive materials may require the use of protecting gas within the build chamber during the curing process, not for it to ignite or explode.

65 Build platform A base in the additive system, upon which the build is started. The build platform, can be moved up and down or in x-y plane.

66 Build area The area with the dimensions within which the print head can move.

67 Build orientation Positioning of the piece in additive system during build process. Build orientation is defined within 3D model design. Right positioning may result in a faster process and better quality of the final object.

68 Build materials AM build material groups are plastics and metals, as well as filled and composite materials, ceramics and ceramic-metal hybrids, and biocompatible materials.
Relevant material properties cover transparency, color, tensile strength, rigidity, biocompatibility, glass transition temperature, moisture resistance, sterilization, fire retardancy, and smoke emissions.
Durometers vary from extremely hard to rubber-like elastomers.

69 Atomization of metal Metallurgy process which starts with the melting of metal material in a furnace, and continues with dispensing it from a reservoir into an atomizing chamber. A high velocity stream of air, inert gas, or water strikes and cools fast the molten metal as it falls, which disintegrates the liquid into fine droplets that fall to the bottom of the atomizing chamber as powder particles.
70 Post-processing If the piece does not meet the required dimensional accuracy or surface finish after the additive manufacturing process, then post-machining and grinding are necessary, although AM aims to avoid the need of post-processing phases. Post-processing includes the removal of support structures, together with the removal and cleaning off of loose powder, and often infiltration. Some photopolymer parts are post-cured using UV light to complete polymerization. To preserve freedom of design, geometry-specific treatments are not used.

71 Post-machining CNC-machining techniques such as CNC-based milling and grinding that are used to change material properties within post-processing to improve surface appearance.

72 Post-build cleanup Within post-processing, the removal and cleaning of loose powder is usually done with compressed air, often from both plastic and metal parts made by powder bed fusion. This needs to be done before post-thermal processes.

73 Post-thermal processes Post-thermal processes are often used to stress-relieve and impart better mechanical properties in the parts.

74 Sintering 1) Associated with the post-processing of an additively manufactured piece, sintering means «  post-heating  » or firing the porous piece in a furnace or oven, where the material melts partially or entirely depending on its material properties.
2) In traditional powdered metal sintering, where the piece is molded with pressure and heated, the final structure of the piece is porous.

«  post-heating  »
75 Infiltration Infiltration is a technique that is used to improve the strength of the parts, by filling the parts with other material through capillary action.. Sintering, i.e. «  post-heating  » of the porous parts, is often attached to infiltration, especially when binder material needs to be burned out from the parts before infiltration.

76 Support removal Supports are removed once the parts have passed all necessary thermal post-processing cycles. Support removal is easier if material of the support structures is different from the build material.

77 Surface finishing The surface of the final piece may be finished with grinding and painting, or with metal coating. Tooling surface often requires mechanical finishing as well.

78 3DP 3D Printing.
First binder jetting-based additive manufacturing technology which was originally developed by MIT. It should not be confused with the current wider meaning of 3D printing.

79 LENS Laser-engineered Net Shaping.
Additive manufacturing technology based on directed energy deposition.

80 FDM Fused Deposition Modeling.
First material extrusion-based additive manufacturing technology which is widely used especially in 3D printers.

81 LS Laser Sintering.
Additive manufacturing technology based on powder bed fusion. Laser sintering is based on powder bed fusion process. Laser sintering involves partial melting in a way that the resulting object has porous structure, thus it needs post-heating. However, in metal powder bed fusion metal particles bind together entirely which leads to a completely dense final structure.

Laser sintering
82 SLS Selective Laser Sintering,
Additive manufacturing technology based on powder bed fusion.

Selective laser sintering
83 SLM Selective Laser Melting.
Additive manufacturing technology based on powder bed fusion.

84 DMLS Direct Metal Laser Sintering.
Additive manufacturing technology based on powder bed fusion.

85 EBM Electron Beam Melting.
Additive manufacturing technology based on powder bed fusion.

86 UAM Ultrasonic Additive Manufacturing.
Additive manufacturing technology based on sheet lamination.

87 LOM Laminated Object Manufacturing.
First sheet lamination-based additive manufacturing technology. No longer used.

88 Stereolithography First vat photopolymerization-based additive manufacturing technology.