Laser stereolithography (abbreviated as SLA and STL from the English. Stereolithography ) is one of the technologies for rapid prototyping . The apparatus for stereolithography was first patented by Chuck Hall in 1984. [one]
Content
Technology Basics
The technology of laser stereolithography is based on photoinduced laser radiation or radiation of mercury lamps for the polymerization of a photopolymerizable composition (FPK).
This method differs from others in that it does not use powders, but photopolymers in the liquid state, as the “building material”. A mesh platform (elevator) is placed in the tank with liquid photopolymer, on which the prototype is "grown".
Using this technology, a three-dimensional object designed on a computer is synthesized from a liquid FPK by successive thin (0.05-0.2 mm) [2] layers formed by laser radiation on a moving platform [3] . As a rule, the processor for forming horizontal sections preliminary converts the description of the 3D model of the future object from the STL file format into a set of layered sections with the required height step, the array of which is written to the executive file with the SLI extension [3] . This file is a set of two-dimensional vector data that provides sequential control of the orientation of the laser beam through the mirrors during the synthesis of the object, commands to turn on the laser, move the platform, etc. [3]
Next, the laser is turned on, acting on those sections of the polymer that correspond to the walls of the target object, causing them to solidify. After that, the entire platform dives a little deeper, by an amount equal to the thickness of the layer. Also at this moment, a special brush irrigates areas that could remain dry due to some surface tension of the liquid. Upon completion of construction, the object is immersed in a bath with special compositions to remove excess and clean. And finally, the final exposure to powerful ultraviolet light for final hardening. Like many other 3D prototyping methods, SLA requires the erection of supporting structures that are manually removed at the end of construction [3] [4] .
Laser stereolithography makes it possible in the shortest time (from several hours to several days) to go from a design or design idea to a finished model of a part [3] [4] .
Features
- Due to selective hardening, rigid two-sided restrictions are imposed on process components and process technology. For example, the thicker the resin initially, the easier it is to transfer it to the polymer state, but the worse its hydromechanical qualities. An excessively liquid polymer requires more time to calm its surface after moving the platform.
- The more powerful the photoinitiator introduced into the resin, the less time a weak laser needs to illuminate, but also the shorter the lifetime for the entire resin volume, since it is exposed to background illumination.
The main difference between manufacturers of laser stereolithographs is the above characteristics, since in general, the device and the principle of operation of such machines are identical. In any SLA machine, it is possible to use any consumables after appropriate adjustment. One of the advantages of 3D printing using the SLA method is its speed, which averages 4-7 mm / hour in height of the model (it depends on the loading of the working platform and the construction step) [2] . One of the manufacturers of equipment for stereolithography, 3D Systems (USA), offers machines with synthesis chamber sizes from 250x250x250 mm to 1500x750x500 mm [2] . The Belgian company Materialize has created an apparatus capable of creating objects up to two meters in size.
Weaknesses
- Among the disadvantages of SLAs, the high cost of both equipment and consumables is usually called [2] .
Applications
- Creation of engineering and design prototypes , models of various products and assemblies.
- Production of forming equipment for various types of precision casting . Creation of models for the manufacture of forming equipment from other materials.
- Creating a master model in the manufacture of electrodes for electrical discharge machining .
- Restoration of objects according to X-ray, acoustic or NMR data in medicine , forensics , archeology , etc.
- Production of microoptics from transparent plastic materials, including for nano UAV video cameras. [five]
See also
- 3D printer
- Development with public experience
Notes
- ↑ Charles W. Hull. US Patent "Apparatus for production of three-dimensional objects by stereolithography" (English) (1984). Date of treatment July 20, 2017.
- ↑ 1 2 3 4 Zlenko M.A., Popovich A.A., Mutylina I.N. Additive technologies in mechanical engineering. - St. Petersburg: Publishing House of the Polytechnic University. - 2013.- S. 87 - 96. - 222 p. - [1]
- ↑ 1 2 3 4 5 B. Slyusar. Fabber technology. A new tool for three-dimensional modeling . The journal "Electronics: science, technology, business" - 2003. - No. 5, p. 54-60. (2003). Date of treatment July 20, 2017.
- ↑ 1 2 V. Slyusar. Factory in every home . Around the world. - No. 1 (2008). - January, 2008. (2008). Date of treatment July 20, 2017.
- ↑ Egorenko M.P., Efremov V.S., Katkov I.A. Prospects for the application of 3D printing technology in the development of optical systems for nanodron video cameras. // Interexpo Geo-Siberia. - Novosibirsk: Siberian State University of Geosystems and Technologies. - Volume 5, No. 2. - 2017 .-- C. 19-23. [2]
Literature
- Laser technology for processing materials: current problems of basic research and applied development - monograph, ed. V. Ya. Panchenko , section “Laser technologies for rapid prototyping and direct fabrication of three-dimensional objects”. - M .: Fizmatlit , 2009 .-- 664 p. - ISBN 978-5-9221-1023-5
Links
- Laser stereolithography // Institute for Laser and Information Technology Problems of the Russian Academy of Sciences
- Laser stereolithography: possibilities and limitations
- Scope of laser stereolithography