HISTORY OF ADDITIVE MANUFACTURING (AM)/ 3D-PRINTING.

Printing is much older technique than CNC machining. Starting in the 1980s, various technologies evolved to add the Z-axis, which allowed machines to build three-dimensional objects from a CAD model or a 3D scan. The original general term for this process was Additive Manufacturing (AM), and the canonical use case was Rapid Prototyping (RP). Nowadays, 3D-Printing (3DP) is a popular term for Additive Manufacturing (AM). 

Additive Manufacturing (AM) has roots in Topography and Photosculpture which date back almost 150 years. The first successful AM process was effectively a powder deposition method with an energy beam proposed by Ciraud in 1972. 

• Topography

As early as 1890, Blanther suggested a layered method for making a mold for topographical relief maps. The method consisted of impressing topographical contour lines on a series of wax plates and cutting these wax plates on these lines. After stacking and smoothing these wax sections, one obtains both a positive and negative three-dimensional surface that corresponds to the terrain indicated by the contour lines. After suitable backing of these surfaces, a paper map is then pressed between the positive and negative forms to create a raised relief map.  

Layered method suggested by Blanther for fabrication of 3D relief maps. 

• Photosculpture

This technology was designed by Frenchman François Willème in 1860. As shown in Figure, a subject or object was placed in a circular room and simultaneously photographed by 24 cameras placed equally about the circumference of the room. An artisan then carved a 1/24th cylindrical portion of the figure using a silhouette of each photograph.

  

Photosculpture in Willème studio.

Reproduced photosculpture from  Willème method.

To make less severe the labor-intensive carving step of Willème's photosculpture, Baese in 1902 described a technique which uses graduated light to expose photosensitive gelatin that expands in proportion to exposure when treated with water. Annular rings of this treated gelatin could then be fixed on a support to make a replica of an object.

Baese filed patent in 1902 for his photosculpture technique.

HISTORY OF MODERN AM TECHNIQUES.

In 1951, Munz proposed a system that has features of present day StereoLithography (SLA) techniques. He disclosed a system for selectively exposing a transparent photo emulsion in a layer-wise fashion where each layer comes from a cross section of a object to be printed. 

Lowering a piston in a cylinder and adding appropriate amounts of photo emulsion and fixing agent create these layers. After exposing and fixing, the resulting solid transparent cylinder contains an image of the object. Subsequently, this object can be manually carved or photochemically etched out to create a 3D object.

Technique suggested by Munz in 1951 for photosculpture.

In 1968, Swainson proposed a process to directly fabricate a plastic pattern by selective three-dimensional polymerization of a photosensitive polymer at the intersection of two laser beams. The object is formed by either photochemically crosslinking or degrading a polymer by simultaneous exposure to intersecting laser beams.

Photochemical SFF system of Swainson.

In 1971 the Frenchman Pierre Ciraud filed a patent application describing

a method for manufacturing articles of any geometry by applying powdered

material, e.g. metal powder, onto a substrate and solidifying it by means of a

beam of energy, e.g. a laser beam. 

To produce an object, small particles are

applied to a matrix by gravity, magnetostatics, electrostatics, 

or positioned by a nozzle located near the matrix. A Laser, Electron Beam or Plasma Beam then heats the particles locally. As a consequence of this heating, the particles adhere to each other to form a continuous layer.

Powder SFF process of Ciraud.

In 1977 another independent, private inventor called Ross Housholder filed a patent application which included a description of a system and method which bore an uncanny resemblance to future commercial laser-sintering systems. 

He discussed sequentially depositing planar layers and solidifying a portion of each layer selectively. The solidification can be achieved by using heat and a selected mask or by using a controlled heat scanning process.  

Powder process of Housholder.

Part produced by Householder.

Hideo Kodama of Nagoya Municipal Industrial Research Institute (NMIRI) was the first to publish an account of a functional photopolymer rapid prototyping system. In his method, a solid model is fabricated by building up a part in layers where exposed areas correspond to a cross-section in the model. 

Stereolithography systems of Kodama.  

Part produced by Householder.

Herbert describes a system that directs a UV laser beam to a photopolymer layer by means of a mirror system on an x-y plotter. In Herbert’s experimental technique, a computer was used to command a laser beam across a layer, the photopolymer vessel was then lowered (1 mm), and additional liquid photopolymer was then added to create a new layer.  

Stereolithography system of Herbert.

Part produced by Householder.

• The first proper commercial system for laser-sintering was the 

Sinterstation 2000 from DTM Corp. of Austin, Texas, first shipped in 

December 1992.

• The second commercial system for laser-sintering was launched by 

EOS GmbH of Munich, Germany, first shipped in April 1994.

• The first commercial system for DMLS was the result of a combination of 

EOS plastic laser-sintering technology and powder metallurgy development 

from Electrolux Rapid Development (ERD) of Rusko, Finland.

• In 1989, Nyrhilä had invented a novel powder concept for 

pressureless sintering with very low shrinkage. The first test systems were 

developed by EOS and installed already in 1994, with the first commercial 

EOSINT M 250 systems being installed in the summer of 1995. 

DTM Sinterstation 2000.

EOSINT M250 Xtended.

Nyrhilä novel powder concept.

     EARLY+LATEST CHRONOLOGICAL WORKFLOW PERIOD OF AM.

Workflow period of AM and patents filed in the past can be better understood from the below-mentioned flowchart.

THE EVOLUTION OF 3D-PRINTING.