The quality of 3D printing surpasses everything else, especially when you’re implementing ideas that are detail-oriented or require more esthetic.
One common issue users encounter is the uneven layer lines in their 3D prints, which takes even the most beautiful design for a toss.
Mastering the first layer of your 3D print works as the building blocks of everything that comes after it and ensures there are no layer lines.
If you’re a 3D printing enthusiast like me and these layer lines give you sleepless nights, you’re in the right place.
The most common factors causing uneven layer lines in your 3d prints are tangled filament, clogged extruder, suboptimal layer height, or temperature fluctuation.
In this article, I’ll give some tips on how to overcome layer lines of your prints and also how to get rid of them.
6 Tips to 3D Print Without Layer Lines
Here are some tips to fix uneven layer lines in your future 3D printing projects:
1. Verify for tangled filament
In a quest to provide quality and quantity printing, it’s easy to overlook the 3D printing filament spool.
The problem starts when your filament spool tangles, which is a nightmare to bear. Even a small tangle or twist can cause inconsistency in how your extruder feeds the filament via the nozzle.
Once the extruder stops pushing the filament, the melted filament clogs the nozzle, resulting in layer lines.
So, if your 3D printer is messing up all your design, start by verifying that the extruder feeds the filament spool to the printer correctly.
You might verify it manually by spinning it and ensuring that the filament unwinds without sticking.
To minimize the instance of tangled filament, use high-quality filaments. If you’re low on budget, select a filament with a slightly rough texture, such as wood, because it hides the layer lines.
Pro-tip: Never unwind the entire spool to find the untangled filament, as it will only add to your woes.
2. Unclog and clean the extruder
Over its useful life, your 3D printer will probably extrude many kilograms of plastic.
What makes things more challenging is that the exit hole for the melted plastic is as tiny as a single grain of sand.
While filament build-up doesn’t clog the extruder, it might allow the filament to pass at the cost of some layers being lumpier than others.
Upon verifying your machine, if you find the clog is the reason for uneven layers, let the machine cool and try to remove the melted or stuck filament out.
Many 3D printer enthusiasts use cleaning filaments to make their life easier and ensure the removal of even the tiniest build-up.
Pro-tip: Nothing lasts forever, extruders included. Wear and tear happen over time, especially when clogged, so focus on regularly cleaning it.
3. Use an optimal printing temperature
While you might be intrigued to use a higher temperature because it allows better layer adhesion, be wary of the problem it tags along.
Your printer might melt extra plastic when the temperature is too high, resulting in prints with layers.
A major difference between the optimal temperature and the temperature at which you’re printing makes your 3D print look melted.
However, a slight temperature difference doesn’t bother you because it results in a small amount of melted plastic.
Try to balance between low and high temperatures for best-quality prints.
Other ways to prevent uneven layer lines are calibrating the temperature every time you change the nozzle and using a temperature tower to know your printer’s optimal temperature.
Pro-tip: Take a few sample prints to determine your 3D printer’s optimal temperature for ensuring prints without layer lines.
4. Avoid printing too quickly
Every time we do something extremely fast or quickly, we’re likely to commit an unforced error.
The same concept applies to 3D prints.
When your extruder moves too fast, it deposits filament on the printer’s side, forming unwanted layers.
When you print too quickly, the printer blobs, droops, strings, and oozes out excess melted filament, resulting in over-extrusion.
To prevent over-extrusion and reduce the printing speed, ensure your layer height is less than the nozzle’s diameter.
Lowering the speed allows the layer to adhere and ensures less filament gets deposited on the sides.
Pro-tip: Reduce the printing speed continuously by 5-10 mm/s.
5. Prevent temperature fluctuations
Temperature fluctuation is another reason you might see layer lines on your print.
On exposure to heat, your filament expands and shrinks, causing the printed object to deform.
In such a scenario, the filament cannot get an optimum temperature for cooling down. As a result, the printing surface has visible layers.
To avoid frequent temperature fluctuation, verify whether your PID controller works as expected.
Pro-tip: Prevent temperature fluctuations by ensuring your 3D printing environment isn’t too cold.
6. Reduce the layer height
As a pixel determines the resolution of your television, layer height determines the resolution of your 3D print.
To eliminate instances of uneven layer lines in your 3D prints, lower the layer’s height.
Lowering the layer’s height requires additional layers to achieve the same height, improving the print’s quality.
As there is no one-size-fit layer height, perform some test prints to know which one works best for your 3D printer.
Reducing the layer height beyond a certain limit makes 3D printing extremely costly.
Typically, the layer height depends upon the filaments and printers used. One excellent way to reduce your layer height is by changing the value in the slicer.
Pro-tip: Try adjusting the temperature and nozzle’s diameter to prevent the low layer height from causing any damage to your 3D print.
How To Get Rid of Layer Lines from 3D Prints
Layer lines on your 3D prints can be annoying because it results in rough textures and makes the print appear more like an injection-molded plastic.
But the good news is you can get rid of layer lines from 3D prints using these two methods:
Sanding
Any attempt to get rid of uneven layer lines requires some amount of sanding.
Sanding 3D prints leave them with a smooth finish. After sanding, you can polish the sanded print for a shiny finish or leave them unpolished for a matte finish.
While you can use sandpaper for a smaller 3D print, use a sanding block for larger prints.
Ensure you have sandpapers in various grits to achieve the desired smoothing result.
Depending upon the smoothing results you want, start with 150 to 220-grit sandpaper and gradually move up to 4000-grit.
You can use power tools like detail sanders, belt sanders, and orbital sanders to sand your 3D print.
Like sandpaper, start with a low grit paper and move up to ultra-fine grit. When using power sanders, monitor the heat build-up, as it can ruin your smoothening process.
Words of caution: Always sand in a circular motion because deep groves might develop if you sand back and forth.
Try covering it with materials
Sanding never completely eliminates uneven layer lines in your 3D printing. Another way to achieve a smooth surface is covering or coating the remaining layer lines with materials, such as epoxy resins and primer spray paint.
Epoxy resin
Unlike sanding, epoxy resins add additional material to your 3D print to remove the unwanted layer lines.
Epoxy is a two-part liquid solution made from unreacted epoxide and a curing or hardening agent.
Mixing the two in the right ratio ensures a smooth 3D print. The correct ratio depends upon the epoxy you use, so read the manufacturer’s instructions carefully.
Interestingly, once you mix these two components, the epoxy solidifies. Depending upon the manufacturer, some epoxy resins might require curing to solidify.
After mixing the solution, apply a thin layer of epoxy on the surface of your 3D print using a paintbrush.
Try applying a thin layer. Otherwise, the epoxy might form drips that are even hard to remove.
When the epoxy solidifies, you can either sand it, leave it as such, or apply another layer of epoxy.
Words of caution: When using epoxy, use nitrile gloves because epoxide easily diffuses through latex gloves, causing damage to your skin. Remember to wear safety goggles because when you apply the epoxy, it generates a lot of heat.
Primer
Another material helping you get rid of those uneven layers is using a primer.
Typically, a primer fills the layer lines to create a smooth surface. After applying a thin layer of primer, let it dry before coating another layer onto it.
You might have to repeat the process two-three times before you sand the top layer down.
However, priming alone won’t suffice as you have to follow up the primed print with painting. You can use spray paints for larger prints.
For those who want to cut down the sanding part, use wood fillers or other filler primers to fill in some of the layer lines. This reduces the sanding requirement and gives your 3D print a nice surface texture for holding the paint.
Words of caution: Always use the paint and primer from the same manufacturer, and never mix enamels and acrylics because this might cause the paint to crack, destroying your hard work.
3D Printing Technology and Layer Lines
The 3D printing technology your printer is using also has an impact on the quality of your prints.
Like selective laser sintering and fused deposition modeling can result in much smoother surfaces than traditional 3D printing methods.
However, even these technologies require post-processing to eliminate the uneven layer lines. Two widely used 3D printing or additive manufacturing technologies are:
Selective laser sintering (SLS)
As the name suggests, SLS uses a laser to fuse the tiny particles of polymer powder into a structure based on the 3D model.
It’s a powder-bed fusion 3D printing ideal for functional prototypes, spare parts, end-use consumer products, and small to medium manufacturing runs.
Parts that you produce using SLS have superior mechanical properties. Even though the printed parts have a rough surface, there are almost no visible layer lines.
Still, the 3D prints require some post-processing for a smoother finish.
Post-processing techniques: Some post-processing techniques include dyeing, painting, liquid polymer coating, electroplating, ceramic coating, powder coating, and vapor smoothing.
Fused Deposition Modeling (FDM)
FDM is a material extrusion method of additive manufacturing, which works by extruding thermoplastic materials through a heated nozzle. The heated nozzle melts the thermoplastic material, and you can apply the plastic layer by layer to create a model.
When compared with SLS, FDM has a lower resolution and accuracy. As a result, FDM-printed parts have more visible layer lines and are unsuitable for printing complex designs. Even then, FDM is a preferred choice for 3D printing.
For prints without layer lines, FDM prints might require one or two post-processing techniques.
Post-processing techniques: Some post-processing techniques you can use are sanding, gap filling, polishing, priming and painting, and vapor finishing.
Final Thoughts
From artificial human organs to household items, 3D printing can replicate every object you can think of.
While occasionally you might encounter layer lines in your 3D prints, once you follow these tips, you will be well on your way to 3D printing without layers.
For that extra push and to achieve a pristine finish, implement post-processing methods like sandpaper and coat your 3D print with epoxy and primer.
As technology advances, you’re likely to see 3D prints with no or fewer visible lines, as seen in SLS 3D printing.
With new 3D printing innovations making their way in the coming years, the problem of layer lines in 3D printing is likely to reduce, giving you aesthetically appealing and smooth 3D printed products.