Exploring the Evolution and Core Technologies of 3D Printing

From design prototypes to life‑saving prosthetics, 3D printing is redefining what we can manufacture. 3D printers now create everything from sand molds to titanium dental implants and turbine blades. The duck depicted above—Buttercup—was born with a severely deformed foot that prevented her from walking. With a custom 3‑D printed prosthetic, Buttercup now walks normally.

Before diving deeper into additive manufacturing, it helps to understand its counterpart: subtractive manufacturing. In conventional subtractive processes, sheets or rods of plastic are milled or cut into shape. Craftech specializes in this area, offering precision CNC machining for plastics. When it comes to metals like steel, the challenge increases. Steel components typically travel through a CNC mill, where carbide end mills carve the final geometry. A high‑rigidity machine is essential to maintain tight tolerances—our 26,000‑lb, 35‑horse‑power mill can reliably achieve 0.001‑inch accuracy. With cooled spindles and high‑pressure coolant, it even performs tasks like gun drilling. Such equipment can cost between $350,000 and $400,000 and has a work envelope of roughly 20″×40″×26″.

Operators of these mills often ask: why not simply layer metal to create the finished part? The answer lies at the heart of 3D printing.

Getting Started with 3D Printing

Every additive project begins with a digital model. Designers use CAD tools such as SolidWorks, Inventor, Siemens NX, or Pro‑E to craft a solid geometry, then export it as an STL (stereolithography) file—the standard format for 3D printers. The term “stereolithography” was coined in 1984 by Charles W. Hull, the inventor of modern 3‑D printing.

The original intent of 3D printing was to produce micro‑scale objects with exceptional precision—known as micro‑fabrication. This early technology combined CNC positioning systems, electrical discharge machining (EDM), and lithography techniques from semiconductor manufacturing to build 3‑D structures layer by layer.

Advances such as the LIGA process soon enabled the creation of real‑size structures with remarkable detail. For instance, a honeycomb lattice 70 µm tall with 8 µm thick walls was fabricated using this method. Functional components like pumps and locks have also been produced.

With these foundations in place, the focus shifted to macro‑printing—creating visible, mass‑bearing parts. Below are the three most widely adopted macro‑printing technologies.

1. Fused Deposition Modeling (FDM)

FDM extrudes a thermoplastic filament—commonly ABS or PLA—through a heated nozzle to build objects layer by layer. It is also adaptable to metal alloys and even food‑grade materials. FDM machines are affordable; many hobbyists start with a MakerBot or similar kit, while industrial models deliver high precision and reliability.

2. Direct Metal Laser Sintering (DMLS)

DMLS fuses metal powder with a laser to create solid parts from virtually any alloy. Because sintered particles may not bond perfectly, post‑build heat treatments are often required to achieve the desired mechanical properties. Some manufacturers integrate an on‑site subtractive milling step to refine tolerances—especially for high‑precision components such as dental implants or aerospace brackets—thereby combining additive and subtractive strengths.

3. Selective Laser Sintering (SLS) / Selective Laser Melting (SLM) / Electron Beam Melting (EBM)

SLM, a variant of SLS, fully melts powder to produce dense, mechanically robust parts. EBM uses an electron beam in high vacuum to melt titanium and other alloys, offering exceptional accuracy. While commercial EBM systems can cost $500,000 or more, the technology remains the gold standard for critical aerospace and medical components.

Beyond printing, 3D scanning plays a pivotal role in the additive workflow. Modern scanners capture a real object’s geometry with the same precision as a coordinate measuring machine (CMM), yet at a fraction of the cost. As scanners become more accessible, they enable rapid prototyping and quality assurance across industries.

3D printing and scanning together form an ecosystem brimming with potential—from bespoke prosthetics to complex aerospace structures.

Share your experience with any of these 3D printing technologies below!

Want to learn more about plastic manufacturing? Check out our complimentary glossary!