About 3D Printing

How "FUSED DEPOSITION MODELING" (FDM) WORKS

"3dprint" colloquially refers to building additively (layer-on-layer). This can be done in several ways, but the most well-known within hobby printing is the FDM method. Fused Deposition Modeling is one of several types of 3dprint, which is also characterized by the printers sold at 3D Eksperten.

OVERVIEW

FDM can be understood as drawing with a very precise glue gun.

FDM (also known, from open source communities, as Fused Filament Fabrication, FFF) works by extruding material through a nozzle. The extruder lays out the material in a thin layer, then moves the position of the nozzle up (vertically) to then lay another layer of material - layer-on-layer-on-layer, etc.

The printer's nozzle/hotend consists of a heater that heats the filament so that it can pass through the nozzle. The plastic/filament that passes through the nozzle to the blank will solidify after a short time, as it binds to the layer that is extruded underneath. By repeating the above process, the subject will be built up, one layer at a time.

In relation to the quality of your prints, this will typically be determined by your layer thickness (layer height). The thinner the layer, the finer the surface. Layer thickness typically varies from 75 (slightly thinner than an A4 sheet) to 300 microns. The FDM technology is a widely used technology within desktop 3d printers and is at the cheap end of the various 3d print technologies.

MATERIALS

FDM printers work with "filament". This is usually rolled on a coil and typically consists of thermoplastic or thermoplastic/organic material (ABS/PLA/NYLON). The most used material within FDM printers are ABS and PLA. PLA is a clear favorite within 3d printing, as it is biodegradable and as it does not emit unpleasant odors/chemicals/vapours when used during printing.

Gradually, more exotic material has come on the market within 3d printing. These include soluble material such as PVA, which is often used as a support material in dual-extrusion (2 nozzles) machines, wood filament (wood-pigmented PLA), stone and rubber-like materials, all of which are increasing in popularity within 3dprint.

If you compare the different technologies, materials within FDM are relatively cheap (120/kg ex. VAT v. 3D Eksperten), which makes the technology incredibly attractive.

HOW DO THEY WORK?

The process within FDM 3dprint begins with software that determines how the 3d printer's extruder(s) will draw each layer that will form the object - it prepares the 3d drawn file so that the printer can work with it.

Printers that have two or more print heads can print in several colors and or use dissolvable material for support, where e.g. areas are located on subjects that have overhangs or other high complexity. A characteristic of FDM printers is that dual-extrusion printers only print alternately with one nozzle at a time.

THE MECHANICS ITSELF

The printing process itself works by a motor feeding filament up to a heating element, which is typically between 170-260" - depending on the print material. As the material softens/melts, material is moved out of the nozzle, which forms the first layer of your print. After a short time, the first layer hardens/cools down, after which the second layer will begin.

The print head and/or build surface (depending on the model) moves in the XY (horizontal) direction, then it will move in the Z (vertical) axis when the first layer is completed.

In this way, the subject is built up layer-by-layer, from the bottom up.

The FDM process uses material for two different purposes; to build up the subject as well as for support material - to support the overhang of the print, so that the printer does not print in the open air (pictures illustrate dual-extruder)

When you have finished printing your subject, with activated support, you will subsequently be able to remove this by breaking it off after printing.