PLA Smoothing: All You Need to Know

With the advent and development of 3D printing newer issues are emerging. Once you’ve finished printing your first dream flower vase or an adorable puppy into real 3D format, your impression is a bit critical: it looks rather like a children’s toy than a smart, admirable masterpiece. You might wonder: ‘Is that really worth it?’

PLA smoothing steps in here.

PLA smoothing involves eliminating the layer lines and making the print surface smooth to ensure a more favorable impression and professional finishing.

Read More About:

• PLA vs PLA⁺ (3 min read)
• 3D Printer Filament Comparison (10 min read)
• Essentials of Drying Filament – PLA, ABS, PETG, Nylon, TPU (5 min read)

The Concept

Okay, you’ve got to understand that you’re not done yet. There are a few things that you need to know first.

The output of a 3D printer is not a finished product. You’ll need to go through a series of finishing works before you have a sterling piece of print.

Here we’ll describe all the necessary processes. We’ll also suggest the best one for you.

Removing Excess Materials

After the printing process is finished you’re likely to find some excess material, like edges from a brim or supports that you need to remove.

There are generally two ways to do it:

1. Utility Knife

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For an amateur level finishing your standard size (11) knife is quite enough. There is, however, another easier tool— a single edged razor blade. With some cautious drags you can have an impressively smooth surface.

2. Rotary Multi Tool

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Having a number of attachments the rotary multi tool can ensure you a professional job of removing excess materials. The satisfactory performance from this tool is achieved particularly because you can reach all the nooks and corners of your print using different appropriate attachments.

Smoothing Your Print

This is the main part that will turn your print into an admirable piece of 3D print.

The most common kind of 3D printing is called FDM (Fused Deposition Modeling) where each layer of plastic is melted into thin slices that are stacked vertically. And here is the problem. When your model has sharp curves or rounded surfaces a very noticeable stair-stepping occurs. This is generally called the layer line. Though some people call it classic and ‘cool’, most want to get rid of it.

There are a range of ways you can fix the layer line issue.

1. From Software

From the ‘quality’ pane of your software you can set your layer height as small as possible. This will noticeably reduce the layer lines. But this will, in turn, significantly increase the printing time. And longer printing time can bring on some unwanted printing problems like warping and filament jam. Also you cannot be certain if you’re going to get a real smooth print just by lessening the layer height.

2. Sanding

As an easy and trouble-free method you can use it for basic smoothing. However, the next methods are smarter and if you sand your print before applying those methods you are certainly going to have a better result.

For a large plain surface you can use a sanding block. This is going to provide you an even wear both on your sandpaper and on your print. And for a print with lots of details nail files could be one of the great choices.

3. 3D Gloop

This product comes in two different versions: for PLA and ABS individually. Also it comes as a kind of gel in a syringe as well as a spray-on version. This is the most effective working method of PLA smoothing and we are going to describe this method in pretty more detail.

Extra Step:

If you find that the gloop has given your print a matt surface (a dull look) there is yet another step you need to go through— using a Brasso metal polish with a paper towel. After that there should be no objection with the smoothing of your print.

The Con:

The only negative side of this product is that it has some health hazards like it is flammable, its vapor or fume (not usually found any) can be toxic and it can leave a little temporary damage if it gets on your cloth or skin. However, taking precautions (like wearing a respirator, safety goggles and some nitrile gloves) will keep you safe from all the hazards.

4. Mixture of Color Spray and Polyurethane

This is another easy method that gives your print an elegant look. All you need to do is to find a color spray that bonds well with plastic (remember, what the FDM process uses are all some kind of plastic). Here are the steps:

• Remove any dust, grain or cat hair that can be trapped in the smoothed out model.
• Spray a layer of paint and quickly spray polyurethane over the layer.
• Immediately Put the print under a fan to dry faster and prevent it from dripping.
• Wait for about 20 minutes for the polyurethane to mix with the coat well and dry.
• After you’ve done several layers, wait for another 24 hours before you coat a final layer.

The major benefit of this process is that you can hide even thicker layer lines (larger layer heights) and thereby decrease printing time.

5. Using XTC-3D

This is also another sticky material that removes the layer lines by filling up the spaces between each line. Here you are going to enjoy a relieving part— it’s shiny itself so you don’t have to use any brasso-like stuff. The process is almost the same as we’ve described under 3D gloop:

• Carefully read through the instruction that comes with.
• Mix two different liquids in the right ratio. Experts suggest you mix them on a shit of aluminum foil.
• Take a regular brush and coat a thin layer.
• Wait for a couple of hours.

And you’re done!

Final Words

There are a number of methods that we did not mention here because we found them redundant. Our purpose has been best served with the ones we focused on.

Wish you a satisfactory 3D print!