Getting your 3D print out of its hotbed is one of best feelings you can ever experience as hobbyists. That elation can suffer when you notice the imperfections inherent in 3D printing? A true maker knows there’s still one more incredibly important step. It’s time to discuss finishing your 3D prints.
Our high standards for our work don’t end at the print bed, and they don’t stop with printing techniques. Instead, the best hobbyists seek to understand and master finishing techniques as well, but there is a lot to learn. If you’ve ever printed something before it’s easy to take a trip down memory lane to the first time you completed a project on your 3D printer. No matter how much work you put into your creation it won’t truly shine until you put that last little bit of work in. Where do you start? The answer is simple, you follow the techniques I will outline below, and come away with a sparkling masterpiece. Let me be your guide so I can aid you in your post-production efforts.
What Have You Created?
You hit that print button hours ago, but it’s done now. Your 3D printer has completed its task. You approach and peer onto the print bed. Gasp… What have you created.
Your 3D print is intertwined with support materials, you have imbalanced layer lines, and enough bumps and blemishes to make Quazimto squirm. Is this normal?
Yes, 100%. Don’t worry. I’ve got you. First, for newcomers, what are those things I just mentioned?
- Support materials: The extra materials a 3D printer uses to support or stop thin or hanging components from collapsing during the printing process.
- Imbalanced layer lines: The prints surface finish either has too much or too little material compared to what you needed.
- Blemishes and bumps: Imperfections caused by any number of things including filament slipping, slicer settings, resolution issues, etc.
Solving these normal as well as structural issues is as simple as applying some easy 3D print finishing techniques using the appropriate tools. Let me show you all you need to know about finishing PLA 3D printed parts while you sit back, relax and take it all in. The approach I’m taking is to examine each of the issues listed above, and a technique for solving it.
Removing Support Materials
There are a couple of techniques which you can apply to remove support materials. For the purpose of this article I am assuming you are using either ABS or PLA filament, or other plastic materials.
Standard Support Removal:
In many cases, support materials can be removed with little effort and simple tools. For this technique, the tools you will need are:
- Needle-nose Pliers
- Scalpel, or craft knife
- Tweezers
- Dental Pick Set
For items 1-3 and more I suggest you get a kit like this one from AMX3D. It will help you with your clean up, with removing your print from the bed, etc. Having a devoted kit next to your 3D Printer is incredibly worthwhile. You don’t have to use the one I suggested. I just like the assortment AMX3D has put together.
Once you have these tools you can start. Keep in mind this is an art more than a science. Having the right tools is only the first step. Afterward, it really depends on what you printed, and what supports are in the way. Choose the tool that best fits the situation, and get to work.
The scalpel can help you cut away the supports and trim down some unwanted hangers-on. The tweezers will help you get into places you can’t get with those big hands. Use the needle nose pliers to twist and pull off some pieces. Dental picks are great at working into grooves and tugging on pieces that need it.
Keep going. Scrape, cut and dig out any erring materials from your print and that’s it. This is a manual process you can do easily once you understand the design of your project.
Dissolvable Support Removal:
If you think the support removal process listed above is tedious, you are not alone. Many 3D printing hobbyists agree. If you want to avoid some of the grunt work and you have a dual extruding 3D printer you are in luck.
Did I say dual extruding 3D printer? Yes, I did. That’s because in order to print a 3D object using dissolvable support materials you need to introduce a filament that is dissolvable. A great example is PVA which works with PLA. It’s the same plastic companies use to make the dissolvable soap packs that go in your laundry or dishwasher. While printing your 3D printer can build supports out of something like PVA, and later you can just wash the supports away.
Assuming you already have a dual extruding 3D printer the first consideration is what filament type your 3D print is. Each filament type has an associated soluble filament associated with it:
- PLA filaments—PVA, is generally associated with PLA materials. Note that it dissolves in water.
- ABS filament—HIPS, is generally associated with ABS. Note it dissolves in a solvent like limonene.
- PLA and ABS—HydroFill, works with both plastics. Note that it dissolves in water.
There are pros and cons to these which we can discuss in a later article. For now, a general understanding of how it works is fine.
Once you’ve selected your filaments and created your print you’ll need to know how to dissolve them.
The tools you will need to do away with these shortlisted dissolvable support materials are:
- Solvent-safe Container, such as Mason jars or other glass jars
- Solvent
This technique is similar to giving your favorite pet a bath. Referring to the list above simply fill up your glass jar with your solvent of choice, but leave enough room to submerge your print. Next, proceed to immerse your 3D print into the solvent and wait for approximately 40 minutes for the solvent to do its work.
This process can bleach your prints depending on the filament, and the process you use. I recommend using a test print first so you know what results you can expect.
Priming, Gap-filling and Smoothing Techniques
Removing the supports is only the beginning. The next step is addressing the lines that come with printing in layers, and any other blemishes that may have appeared. Whether or not you are going to paint your print it’s important to put serious attention into this step.
I say again, this is an art and not a science. I am going to list some tools and techniques below. You won’t always use them in the same order. What you do and when you do it will depend on your print and the process that works best for you.
Remember too, the more you focus your time and effort on this step the better your final product, and the better you will become at future iterations.
Sanding:
We’ll start our delve into the world of priming with the most basic part of the priming process, sanding. As a 3D pringing hobbyist you will become very familiar with the feel of sandpaper in your hands. Personally, I believe every 3D printing tool kit or work station should have the following tools:
- 150, 220, 400, 600, 1000 and 2000 grit sandpaper. (dry and wet)
- A used toothbrush
- Tack cloth
- Detergent
- Water
Once you have successfully removed supporting materials and other hanger-on, the next step is using a sandpaper to smooth the entire surface of your print. Note that the starting grit or grade of sandpaper you start with depends on the quality of your print and its layer height. For example, if you print at a resolution of 200 microns or lower, you should start with the 150.
Once you make your choice, wet the sandpaper with water and then run the sandpaper using small circular motions over places with visible blemishes. Next, clean crevices and moisture using the toothbrush and tack cloth respectively.
Proceed to the next grit, in this order: 400, 600, 1000 and 2000 grit sandpaper until you reach the desired finish. Yes, you can skip some of the grits if you want, but if you move up the line you will have a more consistent result. When sanding make sure you know the thickness of your surface. Sanding is obviously a removal process, and if you go to far you may find you hit a point of no return.
Trivia: Wet sandpaper provides a better finish while reducing the amount of heat caused by the friction between both materials. This protects your 3D print from warping.
Filling Structural Gaps:
3D Printers are far from perfect, and there are times you will have holes or gaps in your print face for a variety of reasons. This is not an uncommon occurrence, and thankfully it’s easy to fix using these tools:
For small wedges, gaps or voids, use an epoxy resin such as XTC 3D to fill up this space with ease. Once applied, it solidifies and becomes another part of your print’s surface.
If you have gaps in an ABS print you can fill them using a mixture of ABS filament and acetone. Mixed together they react chemically to form a slurry. Pouring this slurry into gaps seeps into the print and solidifies. The perfect mix consists of 1 part of ABS filament to 2 parts of acetone.
The ABS slurry is interesting because you can use the filament you already own to create a gap filler that matches in color.
Remember to go back to the sanding process once you’ve finished gap filling to get your surface as even as possible.
Painting:
The application of paint to a 3D print is a finishing technique carried out for various reasons. Paint aesthetically enhances your model and it can also hides blemishes from the naked eye. It can even add an extra layer of protection.
I’ve already covered How to Paint 3D Prints in depth in this article, but I wanted to touch on it briefly in this article as well.
The tools needed for painting a 3D print include:
- Acrylic or aerosol paint
- Hand brushes
- Airbrushes
- Palette
- Painting kit
Get out your favorite hand brushes, or airbrush, and your acrylic paints. It’s time to start. It is important to note that using an airbrush also comes with its own technicalities such as managing air pressure, paint spray and even choosing the right airbrush. You can learn more about the best airbrushes for 3D Printed Models here.
Polishing and Coating:
If a polished surface—which sports a mirror-like finish—is sought after, you need to apply a polishing substance after the sanding. Some people plan on painting their 3D prints. If that’s the case you can skip the polishing step. Some people admire the simple beauty of an unpainted print. For those of you who love the look of your PLA, polishing can lead to some amazing results.
The tools you will need include:
- A plastic polishing compound—Blue Rouge or
- A coating agent—XTC 3D
- Paintbrush
- Microfiber cloth or Buffing wheel
Once your 3D print is fully dry from the sanding process, apply your polishing agent—which is Blue Rouge—using a buffing wheel all over the surface of your model. Once dry your print will have a mirror-like sheen.
For coating with the XTC-3D —, use the paintbrush to apply the coating agent evenly across your print. Applying the XTC 3D will take approximately 10 minutes for small prints. Once done leave it out to dry for 4 hours. It’s worth the wait. At the end you will have a 3D printed object with a high gloss finish which you can still be paint if you choose.
Attaching Components:
When developing or creating complex or large models that have multiple parts you will frequently need to break the model up and assemble it later. After you’ve finished with the above techniques for each piece, you’ll want to attach them together.
Some prints you will create screws, nuts, bolts or tabs that help hold your model together, but in some cases it isn’t possible to do so, or it would just look ugly. In these situations it’s time to employ other techniques which include:
Cold Welding:
This technique focuses on the use of acetone, instead of heat, to attach the different components of a 3D print. It works well with both ABS and PLA 3D printed parts. The tools need to carry this out are:
- Acetone
- An Applicator—foam or ear buds
Clean the surfaces that need to be assembled with a dry cloth and lightly apply acetone to these surfaces. Next, firmly hold these two items together till the making surfaces remain attached.
Note: Attached surfaces although necessary are never as strong as a single 3D print with no components
3D Pen:
This is an odd suggestion, but works great. There are a number of very affordable 3D Pens that can do an amazing job as a glue for your print. Just draw the filament onto the edge you are trying to glue, and press your edges together. What a great and simple idea that avoids the sticky glue messes you might otherwise come across, and provides a strong connection.
Conclusion
Working on your 3D print to achieve the aesthetic standards you want involves putting some considerable effort to learning the techniques discussed above. When done well you will be truly proud of the results. Remember to take your time to do it right. Good luck.