Micro 3D printing – or more precisely, microscale additive manufacturing – is fueling a new miniaturization revolution in everything from microchips to medical devices.
The surging demand for miniaturized devices in electronics, biotechnology, automotive, and aerospace is putting increased interest in the development of microscale additive manufacturing technologies. This 3D printing method can produce tiny parts and components in shapes not possible with traditional manufacturing, faster and at much lower costs. Manufacturers 3D printing their own micro parts in-house are not effected by today’s supply chain disruptions.
As the world moves to 5G bandwidth, these high frequencies and short wavelengths mean tiny antennas and structures; as micro semiconductors find a place in products all around us, the need for micro heat exchangers grows; and as medical treatment becomes more patient-specific, there’s a growing need to make individualized medical devices, such as stents. Although used mostly in research at the moment, microscale additive manufacturing is showing great promise for applications from wearable and embedded sensors to printed circuit boards to 3D printing with living cells.
Although traditional manufacturing techniques (like microinjection molding, micromachining, and etching) can produce precise tiny parts, such processes are complex and costly (especially for single or small batch items), and not many companies exist that can do the work. Additive manufacturing on the microscale provides an alternative to traditional manufacturing, with high-resolution and high-precision parts that are viable for production even up to hundreds of thousands of parts.
Let’s take a look at the technology and machines that are at the forefront of micro 3D printing.
The Basics of Micro 3D Printing Tech
Good commercially available 3D printers for jewelry and medical 3D printing, such as the EnvisionTec Perfactory P4K and the Formlabs Form 3B, can achieve resolutions around 25 – 75 microns (μm), but micro 3D printing gets much smaller.
Additive manufacturing on the microscale generally refers to the production of parts measured in single-digit microns down to a layer thickness of 5 microns and a resolution of 2 microns. Some technologies are even capable of printing parts measurable in nanometers (nm), which is 1,000 times smaller than a micron. For reference, the average width of a human hair is 75 microns and a strand of human DNA is 2.5 nanometers in diameter.
This technology is being used today in everything from luxury watch design to aerospace to medtech, and more.
Most micro 3D printing is accomplished through resin printers, or more specifically, photopolymerization reactions with light. Some companies, however, have begun moving beyond polymers and into the realm of metals, including steel, copper, and gold. Let’s take a look at the five major categories of micro-additive manufacturing technology.
This process is in the vat polymerization family. It involves exposing photosensitive material (liquid resin) to an ultraviolet laser. The general process is the same as for most commercial resin printers: pour resin into a tank, lower a build platform into the resin, a laser draws a cross-section of the 3D part, layer by layer, while the platform is lowered into the chamber. The difference is the sophistication of the lasers and the addition of lenses, which are capable of generating almost unbelievably small points of light, and specialized resins.
Projection Microstereolithography (PµSL)
This additive manufacturing technique is growing due to its low cost, accuracy, speed, and also the range of materials that it can use, which include polymers, biomaterials, and ceramics. It has shown potential in applications ranging from microfluidics and tissue engineering to micro-optics and biomedical microdevices.
The PµSL process is similar to µSLA, except that instead of a laser, PµSL uses ultraviolet light from a projector. The technique allows for rapid photopolymerization of an entire layer of liquid polymer using a flash of UV light at micro-scale resolution, so it’s significantly faster. It’s quite similar to digital light processing (DLP) resin 3D printing technology you’ll see in 3D printers from companies, such as Carbon.