What exactly is 3D Printing, Anyway?

3D Printing Information – Your 3D Printing Magazine

3D Printed Ball

3D Printed Ball

3D printing, or additive manufacturing, is the process by which a user takes a digital file (CAD, STL, etc…), sends it to a device (called a 3D printer), which takes that digital plan and piece by piece, layer by layer (usually) extrudes it out of a tangible material.  (Often plastic, but also metals, etc…)

The processes by which 3D printing, well, 3D prints, is achieved has not changed all that much over the past several years.  Sure, new printers with shiny applications have come and gone, but the actual step by step methods have remained pretty much constant.  Replicator World is a 3D Printing Magazine and 3D Printing Blog, striving to be your source of up to date industry news. 


These standard methods of 3D printing include stereolithography (otherwise known as SLAs or stereolithography apparatus), which involves the positioning of a perforated platform just below the surface of a vat of liquid photocurable polymer.  A UV laser beam then traces the first slice of an object on the surface of this liquid, causing a very thin layer of photopolymer to harden.  The perforated platform is then lowered very slightly and another slice is traced out and hardened by the laser.  Another slice is created and then another, until a complete object has been printed and can be removed from the vat of photopolymer, drained of excess liquid, and cured. 


The upside of the stereolithography method of 3D printing is its accuracy, with a minimum build layer thickness of only 0.06mm (0.0025 of an inch.)  The downside of stereolithography, however, is its price.  The photo-curable resin costs anywhere from $80 to $210 per liter.  A stereolithography capable 3D printer, on top of this, can cost anywhere from $100,000 to more than $500,000.  This is far out of the price range of most makers. 


Another well established form of 3D printing is Fused Deposition Modeling, or FDM.  Using this method, hot thermoplastic is extruded from a temperature-controlled print head to produce fairly robust objects to a high degree of accuracy.  A key benefit of this technique is that objects can be made out of exactly the same thermoplastics used in traditional injection molding.  (Which was the prevailing manufacturing process in many industries prior to the advent of 3D printing.)  Most FDM 3D printers print with both ABS and PLA plastic.


The third form of 3D printing is Selective Laser Sintering, or SLS.  This process builds objects by putting down a fine layer of powder and then using a laser to selectively fuse some of its granules together.  This allows for an output of objects using a wide range of powdered materials such as polystyrene, nylon, glass, ceramics, steel, titanium, and even sterling silver.  In SLS, during the printing process, the non-bonded powder granules support the object as it is constructed.  Once printing is complete, most excess powder is then recycled.  (A closely related 3D printing technique, known as selective laser melting uses a laser to fully melt the powder granules that form a final object, rather than just heating them enough to fuse them together.)


The second to last form of 3D printing, which has been around for a few years, is Multi-Jet Modeling, or MJM.  This method, which is similar to both SLS and SLM, builds up the 3D printed objects from successive layers of powder with an inkjet print had used to spray on a binder solution that selectively glues only the required granules together.    


Just recently, a company called Carbon3D developed yet another form of 3D printing.  Carbon3D called this process CLIP, or ‘continuous liquid interface production technology.’  They claim CLIP  “could be used in industrial applications within the next year…objects created by the new [CLIP] printer seem to ooze into existence from the ether.  They come out fast, too: 25 to 100 times faster than anything on the market now.”


CLIP works by placing “a pool of resin over a digital light projection system.  A special window between the resin and light allows both light and oxygen to travel through (much like a contact lens.)”


“To create an object, CLIP projects specific bursts of light and oxygen.  Light hardens the resin, and oxygen keeps it from hardening.  By controlling light and oxygen exposure in tandem, intricate shapes and lattices can be made in one piece instead of the many layers of material that usually make up a 3D printed object.”

Replicator World strives to be your leading 3D Printing Blog, keeping you up to date on the exciting changes and industry updates within the 3D printing world.  Check back often for new articles and posts relating to 3D printing technologies.

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