Salmon Skin 3D Print Problems? 6 Common Causes (& Fixes)
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- Stepper motor drivers: Low-quality or outdated drivers can cause irregular current flow and vibrations in the stepper motors, leading to salmon skin. Upgrade to better drivers like TMC2209.
- Printer belts and parts: Worn-out or loose belts and parts can reduce the precision and stability of the printer movements, resulting in salmon skin. Replace and tighten the belts and parts regularly.
- Printing speed and surface: High printing speed can create more vibrations and errors in the extrusion, causing salmon skin. Printing on an unstable or uneven surface can also cause wobbling and vibrations. Reduce the speed and print on a flat, rigid surface.
- TL smoothers: TL smoothers are devices that smooth the current flow from the drivers to the motors, reducing voltage spikes and non-linear movements that cause salmon skin. Install TL smoothers between the drivers and the motors for X and Y axes.
Salmon skin is when your 3D print has the look of fresh salmon meat. You’ll notice lines that look like zebra stripes or a series of waves that flow uniformly over the print surface. Sometimes, salmon skin might feel rough to the touch.
Salmon skin is one of the most common but easiest 3D printing problems to fix. In this article, I’ll cover all the causes and fixes of salmon skin.
- Key Takeaways
- 6 Most Common Causes of Salmon Skin Issues
- What Causes Salmon Skin on 3D Prints?
- How to Fix Salmon Skin on 3D Prints
- 1. Outdated Stepper Motor Drivers
- 2. Worn Out and Loose Belts
- 3. Loose Parts
- 4. Low Wall Thickness
- 5. Printing On an Unstable Surface
- 6. High Printing Speeds
- One Final Salmon Skin Fix: Install TL Smoothers
But first, here’s how you can tell if you’re dealing with salmon skin on your 3D prints:
What Causes Salmon Skin on 3D Prints?
Salmon skin happens due to abnormal vibrations within your 3D printer. These vibrations originate mainly from mechanical issues in the 3D printer. However, they can also occur due to low-quality filament, poor bed adhesion, and high printing speeds.
How to Fix Salmon Skin on 3D Prints
To fix salmon skin on 3D prints, stabilize current flow using TL smoothers and upgrade your stepper motor drivers where necessary. You should also print on a stable, flat surface, reduce your printing speed, replace and tighten up your printer belt, and tighten up any loose parts in the printer.
Let’s get into the details of all these causes of salmon skin, and exactly how to fix each issue.
1. Outdated Stepper Motor Drivers
Your stepper motor driver’s quality determines not just how quiet a 3D printer is, but also the likelihood of artifacts occurring during printing.
Stepper motors control the moving components in your 3D printer. They are like little engines, and they get their power supply from stepper motor drivers.
Unfortunately, most manufacturers only use basic stepper motor drivers in entry-level printers to make them more affordable.
If your stepper motor drivers are outdated, they’ll give in to heavy usage, and their efficiency will reduce. They’ll eventually lose their ability to maintain a steady current flow, and this will cause unusual, scaly patterns on your prints – salmon skin.
How To Fix: Upgrade Your Stepper Motor Drivers
Remember how stepper motors get their power from stepper motor drivers? While we also recommend a TL smoother (keep reading for more on this), upgrading your stepper motor driver can be a final resort.
Not all stepper motor drivers are equal, with some being more efficient than others. Their accuracy and efficiency largely depends on their microstepping rating.
Upgrading your stepper driver to one with a higher microstepping rating can dramatically improve precision and reduce the vibrations and noise of the stepper motor.
As a rule of thumb, the higher the denominator in the microstepping rating of a driver, the higher its price, and the quieter and more accurate the printer head is.
Here are some common stepper motor drivers that are compatible with most desktop 3D printer firmware:
|Stepper Motor Driver||Micro-stepping Rating|
If you are considering upgrading the drivers, I’d recommend TMC2209 drivers. They are compatible with many brands, have a wide range of micro-stepping resolutions, and suitably handle high current and voltage loads.
Non-linearity of Stepper Motors
Non-linear stepper motor movements are a major cause of salmon skin. We know that stepper motors work by making small microsteps that move the printer bed and extruder. In theory, these micro-movements are supposed to happen at small regular intervals.
But if the stepper motor doesn’t move linearly, printing accuracy drops as the extrusion becomes choppy. When the extrusion isn’t smooth, you notice a wavy pattern in your prints originating from the non-linear motor movements.
The movement of the stepper motor is controlled by the amount of current flowing from the stepper motor driver. This current must remain constant to maintain accurate microsteps, and any current fluctuation can lead to inaccurate stepper motor motion. Poor current flow in a stepper motor can also disrupt stepper motor movements, leading to salmon skin.
At high speeds, numerous microstep inaccuracies can create significant speed variations in a single motor movement, which in turn leads to increased motor vibration. This extra vibration causes a ripple-like extrusion pattern and we see salmon skin in a print.
On top of that, poor rigidity in the 3D printer makes the problem worse. Printers need to be stable to print accurately. Think of it as your handwriting–it’s much more accurate when you write while seated at a stable desk than in a vehicle moving on a bumpy road.
Salmon Skin from DRV8825 Stepper Drivers
Made by computer chip manufacturer Texas Instruments, the DRV8825 stepper driver is a low-cost stepper motor driver that has been around for decades. But it’s also a common culprit when it comes to salmon skin prints. The reason is because these drivers are notoriously loud and vibrate excessively.
Eliminating Salmon Skin with TMC 2209 Drivers
TMC 2209 drivers are a great line of defense against loud printing. They offer superb efficiency, heat reduction, and greater motor torque control to eliminate possibility of salmon skin formation.
TMC 2209 is fitted with a technology called StealthChop, which smooths the way that stepper motors turn, leading to near-silent movements and less vibration into the printer chassis, further reducing noise and print artifacts.
TMC2209 drivers also have the ability to reduce the motor’s heat generation and energy consumption by up to 90%. The driver uses Trinamic’s StealthChop technology which ensures a noticeably quieter performance than many drivers.
Motors can stall, for example, if they encounter an obstruction along an axis, leading them to lose step count, keep running, and dissipate wasted energy. Using StallGuard technology, TMC2209 drivers can detect when a motor is stalling and preserve energy by stopping movement.
The same technology saves printing costs by eliminating the need for third-party applications that monitor the preciseness of movement where high accuracy is a top priority.
2. Worn Out and Loose Belts
3D printer belts work hand-in-hand with stepper motors. The belts run along the stepper motor driver gears to move the hot end and print bed smoothly and precisely.
Printer belts are usually durable, needing only the occasional tension adjustment.
But, if they wear out (typically after several years) your print head’s movement can become less consistent, resulting in abnormalities and salmon skin effects on your print’s surface. Similarly, if the printer belts are loose, your printer will lose some of its precision, and it will show in your print quality.
How To Fix: Replace the belts
Fortunately, 3D printer belts are cheap, and you can buy them on Amazon for under $15, and they’re also easy to replace on most printers like the Ender 3. There are plenty of guides and videos online that’ll walk you through the process.
3. Loose Parts
Printer belts are not the only 3D printer component that can get loose over time. Other pieces, like nuts and bolts, can lose their tightness over time. This makes your 3D printer’s frame less steady.
And, if you’ve got a rickety structure, your extruder won’t be able to deposit filament as consistently, and and irregularities will show up in the print.
How To Fix: Tighten Loose 3D Printer Components
Get your wrench and hex screwdriver set. Tighten up every screw, nut, and bolt as if you were assembling your printer for the first time – this should get rid of any mechanical shakiness.
4. Low Wall Thickness
Wall thickness is the distance between the outer shell and the infill of a 3D print. If your wall thickness is too small, the infill can become visible on the outside part of your 3D printed object.
All 3D prints have an infill pattern rather than printing solid (we just usually don’t see it on the outside), to save filament costs and printing time.
With too-low wall thickness, this infill pattern can show up as salmon skin on your print’s outer surface.
How To Fix: Adjust Wall Thickness
Adjusting wall thickness ensures the infill has no chance of being visible on the outside. There are different things you can do when adjusting infill settings, but here are two things you can try first:
- Increase wall thickness. The greater your wall thickness, the more opaque your 3D object will be, and the less chance of noticing your infill. If you’re using a 0.4mm nozzle, try a shell thickness of 0.8-1.2mm and you should be fine.
- Lower infill overlap. This is how much the edges of your infill are printed into the outer walls of your print. In most slicers, the infill overlap percentage is 15%. Slightly lower this percentage to create less overlap between the infill and outer walls.
5. Printing On an Unstable Surface
If you use your 3D printer on an unstable, uneven surface, it’ll wobble as it prints. These movements produce unwanted vibrations that pass through the 3D printer and into the print itself, leaving shaky salmon skin patterns.
But how do you know if your surface is the problem?
When your printer stands on a shaky surface, you’ll see the surface tottering or vibrating. Also, you might see the printer vibrating as it runs if placed on unsteady grounds.
How to Fix: Print On A Stable Surface
Make sure your printer is nice and firm as you’re printing. Ideally, you should place your printer on a hard, flat, and rigid surface like a heavy table or desk, or on a rubber mat to dampen any unwanted vibrations. We have written a full article on the best tables and desks for 3D printers.
Avoid printing on light, plastic tables or soft surfaces like a couch or bed.
Reducing the weight of your 3D printer can help reduce vibrations. When your machine is lean and light, parts move with ease and don’t vibrate too much during hefty printing sessions. One popular way to cut down the weight of your 3D printer is by replacing glass plates with lighter steel plates.
6. High Printing Speeds
High printing speeds are notorious for creating print imperfections. If you overwork your printer, naturally you’ll lose precision and quality (especially on a direct drive 3D printer with a heavier extruder).
This reduced accuracy in depositing molten filament causes rippling wavy patterns. Some of these patterns will likely appear as salmon skin on the surface of your 3D prints.
How to Fix: Reduce the Printing Speed
In most slicers, the default printing speed is around 50 mm/s. If you’ve gone way above that mark, reducing the printing speed might fix your salmon skin issues.
However, with printing speed, there is no one-size-fits-all. The correct speed settings really depend on what you’re printing, and the type of filament you’re printing with. For example, you should print TPU and other flexibles at far slower speeds than PLA. There’s always a trade-off between speed and quality.
When lowering your printing speed, avoid lowering it by more than 25% of the default print speed. We also have a detailed guide on the best printing speed settings on the Ender 3.
Salmon Skin from Small Parts
You can eliminate salmon skin by printing at the right speed, especially if you’re printing small parts. By their nature, small parts require your motors to make many micro movements. This is usually fine unless you’re printing at a very fast speed.
At high printing speeds, your 3D printer vibrates much more because it’s using extra power to print. You can avoid this by using a lower speed when printing such parts.
One Final Salmon Skin Fix: Install TL Smoothers
If you’ve tried all the above fixes but still see salmon skin in your prints, it might be time to bring out a TL smoother.
If you’ve tried all the above fixes but still see salmon skin in your prints, it might be time to bring out a TL smoother.
A TL smoother is an 8-diode printed circuit board that is installed between the driver and the motor. It intercepts electric current from the stepper motor driver. It then adjusts it and delivers it to the stepper motor uniformly.
In other words, it blocks voltage spikes that cause the irregular stepper motion that leads to print imperfections like salmon skin and zebra stripes.
Installing TL smoothers is as easy as plugging them into the 3D printer’s X & Y axis.
Here is a step-by-step installation process for TL Smoothers:
- Place double-sided tape on the TL smoothers. The tape will hold them firmly on the circuit board of your 3D printer. Make sure the tape covers the soldered pins on the boards of the TL smoothers.
- Plug in the wire harnesses into the boards of the TL smoother.
- Open the screws on the cover of your printer’s circuit board. On the Ender-3, the circuit board is located under the print bed.
- Unplug the wire harness of the printer’s Y-axis and plug it into one of the TL smoothers.
- Plug the wire harness from the TL smoother into the printer’s Y board connector.
- Peel off the strip of the double-sided tape and stick the Tl smoother on the side of the printer’s circuit board.
- Repeat steps 4-6 for the X-axis.
- Place the circuit board cover back and tighten the screws.
Eliminating Salmon Skin with TL-Smoothers
Although TL smoothers can significantly reduce vibrations in a 3D printer, not every printer needs one. DRV8825 stepper drivers certainly require one, but Trinamic drivers don’t as they already have the feature inbuilt.
Other driver models may benefit only marginally from a TL smoother, while others may not if the cause of the vibrations is from another source in your 3D printer.
If you plan to buy one, you can go with this ARQQ TL smoother from Amazon because it has significantly lower vibrations and less noise while providing a smoother finish.