Engineers have been using additive manufacturing for prototyping for about 30 years now and are also using it for production. However, the biggest value addition from additive manufacturing comes from producing parts that other traditional manufacturing methods find difficult.
Fabricators use additive manufacturing as a valuable and important solution for producing parts such as those including complex design features like internal geometries and cavities that are impossible to achieve by regular machining. Additive manufacturing is helpful in producing structural elements that are too cumbersome or difficult to generate effectively by conventional means.
At present, engineers use 3D printers for printing large parts quickly. These parts may have resolutions around 50 µm and tolerances around 100 µm. However, sometimes, they also need to produce parts with sub-micron resolutions that are smaller than 5 um. Therefore, they needed a system for printing micro-sized parts at a reasonably high print speed.
Smaller parts require a more precise production process. For instance, cell phones and tablets, microfluidic devices for medical pumps, cardiovascular stents, MEMS, industrial sensors, and edge technology components require connectors with high resolution and accuracy. Most standard additive manufacturing machines cannot provide the resolution necessary for micro-sized parts.
BMF or Boston Micro Fabrication designs and manufactures the PµSL or Projection Micro Stereolithography technology-based printers. Using PµSL printers, it is possible to create 3D printed parts with 2 µm resolution at ±10 um scales. These 3D printers incorporate the benefits of both the SLA or stereolithography technologies and the DLP or digital light processing technologies.
Using a flash of ultraviolet light at microscale resolutions, these PµSL printers cause a rapid photopolymerization of an entire layer of resin. This takes place at ultra-high precision, accuracy, and resolution, not possible to achieve with other technologies.
For faster processing, the PµSL technology supports continuous exposure. Other design elements allow additional benefits to the user. For instance, in printers using the standard SLA technology, the bottom-up build method requires a support structure to hold the part to the base, while also supporting the overhanging structures. Conventional SLA systems can typically achieve resolutions of 50 µm, an overall tolerance of ±100 µm, and a minimum feature size of 150 µm. Similarly, standard DLP systems using a similar bottom-up build structure offer 25-50 µm resolution, an overall tolerance of ±75 µm, and a minimum feature size of 50-100 µm.
On the other hand, the PµSL uses a top-down build, thereby minimizing the need for a support structure. It also provides a way to reduce damage while removing bubbles with a transparent membrane. Comparatively, PµSL systems offer resolution down to 2 µm, dimensional tolerances as high as ±10 µm, and minimum feature sizes of 10 µm.
BMF provides this type of quality by properly employing every system component. This includes the resolution of the optics, controlling the exposure and resulting curing, the precision of mechanical components, and the interaction between parts and required support structures. It also depends on the ability to control tolerances across the build and the overall size of the part. Moreover, working with such diverse micro parts requires choosing the right material characteristics.
