Additive manufacturing – AKA 3D Printing – comes in several forms that produce various degrees of detail and part integrity. For most of us, the go-to process is FDM, which generates strong plastic parts at a reasonable cost, using a wide range of polymers to suit many needs.
FDM – Fused Deposition Modeling, also known and MLE (Material Layer Extrusion) – is a process in which a filament of plastic is heated and extruded, tracing the part and its interior, layer by layer. This is the most common process for making strong end-use parts, made from a wide range of materials. FDM printing is also very cost effective, using affordable equipment. Can produce crude optical diffusers, but unsuited to optical forms.
For art produced by the author at Lumenique, we employ a Stratasys F370 Professional grade high performance FDM 3D printer that can print a wide range of plastics. The F370 is a highly reliable printer, that can generate parts that take many days to produce, without failures or quality issues. There are many lower cost machines on the market, but they are not capable of reliably printing large, high quality parts runs without failing. We regularly print jobs that take more than 60 hours, that consume 75 cubic inches of material. We invest in the equipment needed to support this. Our previous Stratasys printer generated over 900 print jobs, with just 2 print failures in the 9 years we had it in operation.
We primarily utilize ABSM30, PC-ABS, ASA, and TPU95, a flexible material that resembles hard rubber. We may also use PLA as a low cost, rapid visualization test material, but not for finished products. The F370 can print any object that will fit into its 12″W, x 10″D, x 14″H build chamber. Larger components than this are printed in sections that are chemically bonded into larger parts or assemblies. Since the materials we use are readily fusion bonded, a finished large assembly of components is as strong as the substrate material, as though it were printed as one.
While in the past, most of the models I have produced were in ABSM30, as it is a very common general purpose plastic, and was the limitation of our first Stratasys Dimension bst1200es printer. Our new machine provides us an opportunity to move up to more modern materials with improved qualities. For most sculptures we use either PC-ABS or ASA. ASA is my go-to material, due to its excellent layer adhesion and surface properties. Since most all sculptures undergo secondary sanding and painting to create a smooth finish, either of these materials take these processes exceptionally well. ASA also has the advantage of being UV stable. ASA is very durable, with strong layer adhesion qualities, and is the plastic many automotive trim and interior parts are made of today. PC-ABS has excellent heat tolerance, with higher rigidity, so serves when these factors are important. ASA and PC-ABS can be bonded to one another with not compromise in strength.
The chart below is a summary of materials we use and have access to for in-house production, showing their general properties for comparison.
FDM Materials Used at Lumenique for Sculpture, End Use Components and Prototyping
|Metric||ABSM30||ASA||PC ABS||Diran (Acetyl)||TPU92A (Rubber)||ABS+Carbon||PLA|
|Tensile Yeild||Good||Good||Very Good||Excellent||n/a||Very Good||Good|
|Impact Strength||Good||Very Good||Fair||Excellent||Excellent||Fair||Poor|
|Flex Bending Force||320,000psi||240,000psi||310,000psi||185,000psi||2,500psi||309,000psi||272,526psi|
|Flex Break Strength||Good||Good||Very Good||Excellent||n/a||Excellent||Fair|
|Stretch at Break||7%||9%||6%||4%||552%||2.7%||1.4%|
|Sand and Finish||Good||Excellent||Good||Poor||Poor||Good||Good|
|Long Term Durability||Good||Excellent||Good||Excellent||Good||Good||Fair|
The ability to tune a design and material to produce parts that are specific to the intended end use is an advancement in creative technologies that is revolutionary. Creating sculpture that can be refined, tested, then produced with minimal waste, and adjusted as needed to produce the desire end result, is a dream come true for 3 dimensional artists.
Other AM Processes used in 3D Printing
For reference, the following are other Additive Manufacturing Processes used to create parts. While we currently do not employ these in-house, there are instances where we may chose to employ a service bureau to make parts for us to suit a special requirement.
PBF – Powder Bed Fusion – is a process in which lasers, electron beams or thermal print heads melt and fuse the surface of a material in powder form, layer by layer. Versions of this include SLS (Selective Laser Sintering), EMB (Electron Beam Melting), and DMLM (Direct Metal Laser Melting). This process can produce highly detailed metal parts from a variety of metal alloys.
MJM -Material Jet Manufacturing – a process in which material in liquid form is printed onto a support bed of inert material, similar to ink-jet printing, layer by layer. This can be multiple color. Used primarily for prototyping.
VPP – Vat Photo Polymerization, also known as SLA (Stereo Lithography Apparatus) – a process where a vat of photo sensitive material is cured by UV laser or UV through LCD imagery, to cure each layer. One of the earliest forms of 3D printing for prototype part making. Can produce optical diffusers and lenses.
SLM – Sheet Lamination Manufacturing, also know as LOM (Laminated Object Manufacturing), and UAM (Ultrasonic Additive Manufacturing) which employs layers of material (paper or metals) cut by layer and adhered in stacks. This process is generally used for visualization purposes.
DED – Direct Energy Deposition, similar to FDM, uses electron beams or lasers that melt material filaments or powders along the profiles and solid bodies, layer by layer. Can be used with metal, ceramic, or polymers.
DLS – Digital Light Synthesis – utilizes light and heat to create polymer parts in a wide range of production grade plastics.
Printoptical Technology(R) – an exclusive process by Luximprint, that prints optically clear polymers to create optical lenses that do not require secondary surface processing, and do not suffer yellowing from UV cure processes.