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Salmon skin effect 3d printing
Salmon skin is a recognizable print defect, for some, it is horrible to see, others find it characteristic. Despite all of this nobody wants it on their prints.
Salmon skin occurs when the outer layers are not uniform but have a rather scaly effect.
How to recognize the salmon skin effect
Salmon skin occurs when imperceptible curves appear on the perimeters oddly arranged like salmon meat. In fact, even if the problem translates to salmon skin, it is much more similar to salmon meat. Look closely at the photos, notice a similarity?
As you can see, however, the effects are very similar!
What causes salmon skin on 3D print
It originates from a non-linearity of the stepper motors consolidated by a lack of rigidity of the mechanical structure. The main problem is that the current flow generated by the drivers is prone to errors and must be softened. DRV8825 stepper drivers are the most exposed to this problem and always manifest it.
Other drivers may have this problem too! When buying a new printer it is a good thing to take into consideration the motherboard. Some motherboards like the MKS Gen V1.4, Arduino DUE with RAMPS-FD or BIGTREETECH SKR V1.2 32Bit have changeable drivers which could be a good thing for 2 reasons:
- If one of the drivers breaks you only need to change one driver and not the whole board.
- You can upgrade your drivers in a second moment
Usually, stepper drivers like the Allegro A4988, or the DRV8825 have this problem. They are so common because they’re both cheap and good enough. Most of what you pay for more expensive drivers is silence and extra features.
Excluding the electronic part, salmon skin can occur in rare cases from the mechanical parts. Strong vibrations or a loose belt can make your printer vibrate in such a way that it creates this effect, but this occurs in only 15% of the cases.
Eliminating salmon skin on 3D Prints
As I told earlier the problem can occur for various reasons. The most intelligent thing to do when it presents is to tighten all the nuts and bolts and check for strange movements and vibrations. It could be anything. So tighten all the vital parts and watch for movements.
This can be avoided using a lower speed when we need to print small parts that require lots of fast micromovements the best thing to do is to lower the speed
Now looking into the electronic part, is vital to know what driver we are already using.
Eliminating salmon skin DRV8825
Unfortunately, we cannot invent many solutions, there is only one! That is the installation of particular pulse reworkers, called TL-Smoother.
These electronic devices consisting of 8 diodes that are installed between the driver and the motor. They absorb the incoming electric current from the card and rework it to make the prints smoother. Here is an example of before and after the installation of the TL-Smoother.
The difference is noticeable to the naked eye.
TL-Smoothers are very easy to install. Just disconnect the wire terminal from the motor and connect it to the smoother, and connect the latter’s cable to the motor. This simple operation will transform your 3d printer from a discrete quality machine to excellent. If you have a motherboard with these drivers then this is an upgrade you really need to do!
Eliminating salmon skin with replaceable drivers
Usually, motherboards aren’t fitted with top quality stepper drivers as that would increase the price of the 3D printer, making their product less competitive. But for us, this could be a great investment! Stepper drivers like the TMC 2209 work great with most of the motherboards used . Using these stepper drivers is the quickest and cheapest solution to eliminate lots of problems like noise and strange artifact. They simply make the movements much smoother and controlled, increasing the printing quality and eliminating salmon skin from 3d prints.
The 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.
Conclusion
Salmon skin is a common problem especially for entry-level 3d printers and usually, it can be fixed by upgrading the stepper drivers or reducing vibrations in the chassis of the printer. In my opinion, is one of the first things to upgrade on a 3D printer, as the changes are obvious and reducing the noise of the printer is also a huge plus.
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