In our previous articles in “Getting started with 3D printing series”, we have provided a step-by-step guide to 3d printing from the moment you have chosen the appropriate hardware. We explained how to generate your CAD (Computer-aided design) model for those wanting to design the 3D object themselves, as well as for the users that prefer to download object files from other designers. Once you have managed to create or repair your STL ﬁle, you need to feed it into the slicing software. The slicing software converts the STL ﬁle into a machine code, the ‘g-code’, which is basically the path per layer that the 3D printer must follow in order to construct the printed object. Software is the second most important thing when it comes to 3D printing. In our last article we provided a detailed selection of the best free slicer software required to prepare and execute a 3D print. Today we will finally discuss about the actual printing and the surface finishing.
THE PRINTING PROCESS
Now that you have your ‘g-code’, the 3D printer has its marching orders on exactly how to execute the necessary movements to realize your print. As explained, the g-code enables the printer to see the STL ﬁle as a list of coordinates for the print head to follow for depositing material. There are two ways in which this is accomplished. If the 3D printer is linked to your PC, the data stream goes from your PC to the printer via a cable. The main drawback with this method is that the print will fail if the connection breaks off or the PC crashes. If the 3D printer is linked with an SD card, the data stream flows from the SD card to the printer. This is a stand-alone operation and is less prone to fail if the other hardware fails. Make sure you have set up your device properly. Each device has its own prerequisites for how to use it for every new print, such as adding the materials the printer will use. When the moment comes for the actual printing, the whole procedure is mainly automatic. The thickness of layers is about more or less 0,1 mm each. Depending on the size of the object, the 3D printer and the materials employed, the procedure could take from several hours to several days.
THE POST PROCESSING
Once you have removed carefully your printed object, you may need to clean your print’s surface. It may happen so that after an object is 3D printed it will require some post-processing, depending on the quality of your printer and of the filament you used. Certain printing techniques require internal supports to be built for overhanging features during construction. These supports must be mechanically removed or dissolved upon completion of the print. Once you remove the support structure and any potential overhang or stringing, your print will be ready, but the surface finishing will probably not be optimal yet. There are several techniques to smoothen the surface of your prints, such as sanding, chemical vapor, coating, painting, etc. The choice of each finishing technique depends largely on part geometry and the material you used. Different methods allow for different textures and appearances.
A common finishing technique for the FDM objects is sanding. Sanding is an inexpensive, effective, and proven method to reach a smooth finish. It is consistently the most widely used finishing technique for 3D-printed parts. It’s recommended to be avoided for the tiny parts. Some printable polymers such as ABS, allow the surface finishing to be smoothed and improved using chemical vapor processes. When it comes to coating, it can be both decorative and functional. For instance metal coating gives the appearance of production metal or plated parts and provides a hard, wear-resistant surface with reflective properties. Painting 3D printed parts is a vast world of acrylics, enamels, sprays, and airbrushes. After sanding, you may add an initial coat of primer and inspect the surface again for imperfections. Primer is a special type of paint that adheres strongly to the part and provides a uniform surface for paint to bond with. After the specified drying time, the part is ready for painting. There are several tips for a smooth paint job and it’s always preferable to finish with a clear coat to protect the paint job. Some additive manufacturing techniques are capable of using multiple materials in the course of constructing parts. These techniques are able to print in multiple colors and color combinations simultaneously, and would not necessarily require painting.print in multiple colors and color combinations simultaneously, and would not necessarily require painting.
We just completed our “Getting started with 3D printing” series! We hope that our posts inspired more people to get into designing for 3D printing and that they will do a lot of exciting work.
We will stay committed to our mission, making 3D printing available to everyone. Since you're now ready to start, we will continue our research to provide you with the latest news,tips and tricks on 3D printing. Our next articles will cover a great variety of topics and will be located on our blog page under the category "All you can know". In case you need to freshen up your memory on the basics, our previous "Getting started" series can be found on our blog page or you can download our free ebook for a more expanded version of the series.