An Unforgettable Summer Job

In the summer of 1981, Carl Decker had completed his freshman year studying mechanical engineering at the University of Texas in Austin. He traveled to Houston for a summer job with a machine shop that made parts for the nearby oil fields. Many of the parts were made from castings which had to be shaped using handcrafted molds. Decker recognized the need for a method to automatically create castings from CAD drawings and began thinking of ways it could be done.

By the time he was ready to graduate, in 1984, he had developed the idea of using a beam of energy, such as a laser, to melt particles into a solid 3D object. He continued to work on the idea, developed the Selective Laser Sintering (SLS) process and formed the company DTM Corp which was sold to 3D Systems in 2001. SLS continues to be an important part of the 3D System product line.

Selective Laser Sintering is a 3D printing method that uses a high powered laser beam to fuse small particles of plastic, metal, ceramic or glass into a solid layer. After each layer is fused, the part is lowered, a new layer of powder is applied on top of the first layer, and the fusing process is repeated. The bulk powder in the SLS machine is preheated to nearly the fusing temperature to reduce the amount of laser energy required.

Selective Laser Sintering Diagram from Wikipedia

The most common uses for SLS technology are rapid prototyping, additive manufacturing of complex or low volume plastic parts and fabrication of casting patterns.

When the SLS process is used to manufacture metal parts, it is usually called Selective Laser Melting (SLM). The Swedish company Arcam AB has a similar system which replaces the laser beam with an electron beam and is appropriately named Electron Beam Melting (EBM).  These processes are typically used to make parts for aerospace companies, personalized orthopedic implants and jewelry.

In 1993 Ely Sachs and Mike Cima of the Massachusetts Institute of Technology developed a process that uses a powder bed like SLS, but binds the powder with glue injected using a print head similar to an inkjet printer. The process, which they named 3D Printing (3DP), was sold to Z Corp which was acquired by 3D Systems in January 2012. Z Corp created the first full color 3D printer by combining color print heads with the binder print head.

The invention of the SLS process by Carl Decker after three years of reflection on the idea he originally formed during his summer job is a great example of the need to let ideas simmer to allow the brain to connect the dots in a new and unique way.

What's cooking in the back of your mind?


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