Hexastorm has build a new type of laser diode scanner; the transparent polygon scanner. Note that this relates to scanning in the broader sense, not the specific form of scanning used to capture 2D and 3D images and shapes. The technology can have a big impact on 3D printing. To clarify, the Hexastorm is put in perspective by comparing it with a Fused Filament Fabrication (FFF) printer. The smallest element of a FFF printer is the nozzle which is a circle with a 300 micrometers diameter. In the latest Hexastorm, this is an elliptical laser spot which is 50 by 60 micrometers. The standard spot speed of a FFF printer is 50-80 millimeters per second. The Hexastorm is able to reach a spot speed of 100 to 467 meters per second. The maximum scan length is 24 mm. The speed of a whole scan line is 16 to 84 mm/s. The outline of the project description is as follows. We start by listing the applications of laser scanners, list the specifications of the Hexastorm, give a brief overview of the technology and outline what source code has been developed
The market for laser scanners is extremely large as they can be applied on various processes, for example; laser direct imaging of printed circuit boards, 3D printing, self-driving cars, laser printers and microscopes. The current version of the Hexastorm is targeted at hardware developers in the 3D printing market. At a wavelength of 405 nm, possible applications are the fabrication of advanced ceramics or metals via photo-polymers, 3D printing of hydrogels, microfluidic devices, dentures, earmolds and jewelry. Of course, if this wavelength is varied and the laser power is sufficient, a transparent polygon could be used to sinter plastics or melt metals.
The transparent polygon scanner consists out of a laser diode which
is focused directly with an aspherical lens. The bundle refracts through
a transparent polygon and is directed to the surface with a 45 degrees
first sided mirror. The bundle is deflected by tilting the transparent
The position of the laser bundle is monitored by a photo-diode. A Field
Programmable Gate Array (FPGA) is used to ensure the correct timing of and stream data to the laser diode.
A detailed explanation, analytical model, review of other exposure technologies and patent analysis has been made available via Reprap.
The technology has four advantages: high optical quality, cost effectiveness, scalable for industrial applications and open hardware.
High optical quality
The transparent polygon scanner projects at 90 degrees of incidence and has a flat field projection, see figure. A numerical and analytical model is available here https://github.com/hexastorm/opticaldesign .
To mitigate in a reflective polygon scanner the simple lens is replaced with a telecentric f-theta lens. In the figure, you can also clearly see that in a transparent polygon scanner the bundle is focused before it hits the transparent prism and must be rotated to translate the bundle.
A high optical quality can be obtained without an expensive f-theta lens.
The maximum optical power of laser diodes becomes less as their wavelength becomes shorter. As a result, laser diodes need to be combined to give more power. It is, however, not possible to combine more than two lasers into a single bundle without interference. The electromagnetic field only allows for up to two polarizations. Due to its high optical quality and cost effectiveness, the Hexastorm is very scalable and suited for systems with multiple bundles. An example of such a system is shown here.
Wide range of applications
The current applications we envision; bioprinter, photopolymer printer and device for the creation of microfluidics (see presentation).
The current version of the Hexastorm has the following specifications:
- wavelength: 405 nm
- rotation frequency: 67-350 Hertz*
- spot size: elliptical, 50 (short...