New to micro-stereolithography? Read this.

Micro-stereolithography, or micro 3D printing in general is often misunderstood due to frequent confusion between technical features like printer size, layer height, optical resolution, and minimum feature size.

If you are a mechanical engineer working on miniaturized components, you are probably familiar with micro-CNC machining and micro-injection molding processes. If you have not evaluated additive micro manufacturing technologies recently, you should probably have another look at the latest micro 3D printers for your prototyping and production needs.

In this post, we will provide some technical definitions for micro 3D printing, review best-in-class printer capabilities, and go through examples of industrial applications. We will also provide an overview of Qualified3D’s current on-demand printing capabilities and available materials.

Cell culture scaffold printed at 2μm resolution on a BMF printer

What is micro 3D printing?

Micro 3D printing is a family of additive manufacturing processes that produces high-precision parts with micro-sized features. These processes are usually based on stereolithography (SLA) in which successive layers of photocurable resin are selectively solidified by targeted UV light to fabricate 3D objects. Each process variant differentiates itself by its source of UV light (laser beam or DLP projector), system layout, and special features deployed to reach micro resolution and tolerances.

Current industrial micro 3D printers have resolutions of a few microns. Some new laser-based processes are able to reach sub-micron resolutions (two-photon lithography for instance), but the slow speed of these linear path processes (3 mm2/h typical) currently limits them to nano-sized objects in R&D applications. For industrial applications such as rapid prototyping of miniaturized medical and electronic devices, DLP projector-based processes are preferred because of their reliability and ability to print objects much faster by creating each layer in a single step, regardless of pattern size and complexity.

Qualified3D’s micro 3D printing service relies on BMF Precision nanoArch printers with PμLSE (Projection Micro Litho Stereo Exposure), a technology ten times more accurate than traditional SLA, which was developed at the Massachusetts Institute of Technology (MIT) for the research and development of functional composite materials.

BMF nanoArch S140 printer

For the best ratio between accuracy and speed, our standard micro 3D prints are produced with a 10 µm (.0004”) optical resolution, 20 µm (.0008”) layer thickness and dimensional tolerances of less than  ± 40µm ( ± .0016”). You can get instant quotes at that precision level, or contact us for a special quote if you need even higher accuracy.

As a reference, the human hair thickness ranges from 40 µm to 100 µm (.0016” to .0039”). You will find an overview of our micro 3D printing capabilities at https://www.qualified3d.com/micro-3d-printing/.

Why is micro 3D printing Important?

Product development engineers rely on additive manufacturing methods to create functional prototypes and test them early to get to market faster. In most high-volume applications, production parts are then manufactured using other production methods such as injection molding.

Until recently, conventional SLA printing technologies were not able to match the precision level of micro-molded parts. Commercially available 3D printing services were limited to feature sizes in the range of 50µm (.002”). Therefore, development engineers often had to use expensive prototyping methods such as micro-CNC machining or – more commonly – wait 8 to 10 weeks for the completion of a first set of micro injection molds before testing their parts, slowing down the development cycle.

Today, micro 3D printing techniques have reached resolution levels that match the precision of micro-molded parts. Beyond technical specs, the productivity of micro DLP printers also opens new possibilities for low-volume production runs and customized parts. The absence of fixed tooling even allows testing several designs concurrently.

Which materials are available for micro 3D printing?

We offer six different micro 3D printing resins with properties and mechanical characteristics far beyond other commercially available micro 3D printing resins.

Our most frequently ordered material is the HEK “Strong and Tough” resin which features 10,150 psi tensile strength, 377,000 psi tensile modulus, 14% elongation at break and a 180°F heat deflection temperature.

Our material lineup includes a biocompatible BIO resin.


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