Although there are numerous post-processing methods available for 3D printing, the most popular one is sanding, which requires more manual labor. You can feel intimidated at first by the idea of spending hours sanding. Have faith; there are ways to accomplish your goals more quickly and with a higher level of professionalism. Sanding is the go-to method for making 3D prints smooth. Reason being, it’s time-consuming but worth it because it’s simple, inexpensive, and yields the best outcomes. Here, we’ll go over the ins and outs of sanding your 3D prints, including all the things you need to know. Then, roll up your sleeves and join me in getting things done.
What is Sanding in 3D Printing?
An inexpensive and popular 3D printing method is extrusion-based printing. On the other hand, when you’re ready to complete printing a part, you’ll see those pesky layer lines. If you need a smooth surface, post-processing is what you need. For a smooth finish free of layer lines, sanding is the way to go. While it does necessitate a fair degree of expertise and experience to accomplish a high-quality result, it may be somewhat labor-intensive. Furthermore, sanding can also eliminate surface imperfections, such as support markings, from the printed object.
Using sandpaper to smooth off the printed part’s peaks is a typical sanding procedure. You will have a flat model that is ready for the next post-processing step after you have removed all the high points. Time is of the essence at this stage, so don’t try to save it by applying multiple coats of paint.
How Sanding 3D Prints Can be Beneficial for You?
Sanding is usually necessary to have a better finish, even after you’ve done everything you can. But sanding isn’t always worth the effort.
1. Ensuring safety and comfort
It is crucial to consistently eliminate sharp edges and rough surfaces. Wearable uses, such as costumes or prosthetics, may find PLA uncomfortable despite its lack of sharpness. Examine it well with your hands, and then use coarse sandpaper or a file to smooth off any rough spots. If you do this early, you won’t have to worry as much about ripping the sandpaper when you sand forcefully later on.
2. Fitting parts with accuracy
Fitting mechanical parts with pinpoint accuracy is essential. Keep cylinders and flats as much as possible. Function dictates the exact clearances needed for shafts and holes, but your printer’s precision may also necessitate some fine-tuning. Carefully designate areas to be removed and test fit pieces before and while sanding. Be careful not to sand too much.
3. Aesthetic
The visual appeal of a print is crucial, not only for practical items like promotional materials or film props, but also for pure pride in one’s work. A primary goal in each of these instances is the elimination of layer lines.
Sanding 3D Prints: How is it Done?
1. Pick out the proper tools
Selecting appropriate tools is the initial stage in preparing PLA prints for sanding and polishing. Depending on the degree of smoothness and detail you desire, you will require sandpaper with varying grits, from coarse to fine. A polishing compound, a gentle cloth, and a sanding block are also necessities. Be cautious not to overheat the PLA and ruin the details while using a rotary tool or a drill fitted with a sanding or polishing attachment. Manual sanding and polishing, on the other hand, is more time-consuming but provides greater control.
2. Begin by sanding gently without wet materials
The following stage is to begin with dry sanding, which entails utilizing sandpaper devoid of any oil or water. Dry sanding is an effective method for smoothing out surfaces and removing big flaws like blobs, threads, or gaps. Lightly press down on the print while you sand it in a circular motion using coarse grit (100 or 150 is a good starting point). A sanding block can help you maintain uniform sandpaper thickness. You don’t want to make divots or scratches by sanding too heavily in one area. To get a level surface, start with a coarse grit and work your way up to finer ones, like 220, 320, or 400.
3. Use wet sanding to finish
To complete the process, wet sand the surface using sandpaper dampened with water or lubricant (soap, oil, etc.). Wet sanding is an effective method for achieving a finer and smoother surface since it minimizes heat and friction while simultaneously eliminating dust and debris. Another benefit of wet sanding is that it smooths out the surface by filling in the tiny scratches that dry sanding leaves behind. Gently sand the pattern in a circular motion using fine grit (600 or 800 is a good choice) while applying mild pressure. Maintaining moist and clean sandpaper is as easy as using a sponge or a gentle cloth. Regular rinsing will remove any residue from the print and sandpaper. Gradually work your way up to finer grits (1000, 1500, or 2000) until the surface is shiny and smooth.
4. Put on some polishing compound
Finally, use a polishing compound—a paste or liquid containing abrasive particles—to buff and shine the surface even more. Polishing compounds created specifically for plastics are available at stores like Novus and Meguiar’s, but you can also make your own with ingredients like baking soda and toothpaste. Lightly press a soft cloth or buffing pad with a little amount of polishing compound and rub it in a circular motion over the print. Be cautious not to overheat the PLA or harm the details while using a rotary tool or a drill with a buffing attachment. Manual polishing, on the other hand, will take more time but will allow you greater control. With a clean towel, remove any excess compound, and then marvel at your flawless and sparkling PLA print.
Tips and Tricks for Sanding PLA Prints to Achieve a Smooth Finish
If you want to save time sanding by hand, use these tips:
- Printing three perimeters or shells or making walls at least 1.2 mm thick will help if you intend to sand the print. Extreme caution is required for any wall thinner than this.
- Work your way up to fine grit sandpaper from coarse grit. However, the print’s dimensions and shape must be considered. Your expectations for the surface quality will determine this. To prepare the polycarbonate for painting, all you need is 240 grit sandpaper, which will also leave a lovely key.
- A coarse grit, such 80 grit, will effectively remove the material from layer lines. Before painting, use a 120 grit to follow the 80 grit, and then a 240 grit to finish.
- You may achieve a lovely matte finish on polycarbonate by using sandpaper with a higher grit, up to 600, if you aren’t planning on painting the surface.
- For best results, use a high-density foam block as a backing for your sandpaper and sand in small circular strokes. Foam allows for the distribution of pressure to be more uniform, leading to a less bumpy surface.
- While sanding, water is also an essential ingredient. Sanding generates heat, and this aids in dissipating that heat. In addition to preventing dust, it aids in keeping the sandpaper clean.
- Using water will help keep the temperature down, as sanding friction may generate a lot of heat—even reaching the material’s Tg in some instances.
- Wear a face mask at all times while you sand. It will aid in keeping dust from sanding out of your lungs.
Overall Best 3D Modeling and Slicing Software – “SelfCAD”
There are a lot of 3D printing software available that you can use to create your files and even prepare them for 3D printing. A good example is SelfCAD. SelfCAD is an easy-to-use 3D design software that has been designed for both beginners and professionals. It comes with various tools like freehand drawing and sketching that you can use to create your 3D models from scratch. You can also use the image to 3D model tool to convert photos to 3D models.
In addition to 3D modeling tools, SelfCAD comes with various 3D printing tools that are useful for preparing your files for 3D printing. For example, there is the magic fix tool that you can use to fix any meshes with your design and ensure that all polygons are manifold and it ensures the file is watertight. Get to know how to use the magic fix tool of SelfCAD in the video below.
SelfCAD also comes with its own in-built online slicer that you can use to slice your designs and generate the G-code to send to your 3D printer. The video below shows how SelfCAD works.
Final Verdict
The gold standard for smoothing 3D printing is sanding and painting. It requires a lot of manual labor but is inexpensive and produces excellent results. You may sand a 3D-printed part just like any other product. If you want a specific outcome, use a low grit and gradually increase it. For optimal results but a lot of work, use sandpaper with grits up to 200. With paint added, though, using 200-grit sandpaper probably won’t make much of a difference. One benefit of sanding and painting is that it allows you to control the finish quality and is the cheapest approach. You should expect to pay a few bucks per print for the sandpaper.
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