How to Fix Layer Shifts on Your Prusa MK4
December 12, 2024
The Prusa MK4 is marketed as a high-speed printer capable of impressive print times, but many users (ourselves included) have encountered frustrating layer shifts that seem to occur at random. During the development of our automation system, we encountered these exact issues across multiple machines. After extensive testing, we discovered that what appears as random layer shifts actually has several specific causes - and more importantly, reliable solutions.
Contents:
Understanding Layer Shifts on the MK4
Layer shifts on the MK4 typically manifest in two ways. First, you might notice small, seemingly random shifts in the X-axis during rapid movements. Second, and often more dramatic, are larger shifts in both X and Y directions, which frequently occur during high-speed printing with Input Shaper enabled.
What makes these issues particularly frustrating is that they can persist even after performing standard maintenance. We found they tend to occur more frequently with heavier spools or sticky materials like PETG, and they're most often observed during travel moves when the printer is operating at high speeds.
Common Causes
Through our testing, we identified several key factors that contribute to layer shifts. The primary culprit is often filament tension pulling on the print head during rapid movements. This is compounded by nozzle catching on parts during travel moves, especially with materials like PETG that tend to create more surface irregularities. We also discovered that some motor limitations at high speeds, combined with environmental factors affecting motor performance, can create conditions where layer shifts become more likely.
Solutions: From Basic to Advanced
1. Start with the Basics
Before diving into more complex solutions, it's essential to ensure your printer is properly maintained. Begin with these fundamental checks:
- Clear any debris from X and Y axes
- Clean and lubricate linear rods
- Check belt tension on both axes
- Verify all screws are properly tightened
- Confirm axes are properly aligned
While these might seem obvious, they form the foundation for reliable high-speed printing.
2. Address Filament Tension
What we initially thought were random X-axis layer shifts turned out to have a surprising cause: excess tension in the filament line. When the print head moves rapidly from one side of the bed to the other, the filament can pull back on the print head. This pulling force, combined with rapid acceleration, can cause the X-axis to skip steps.
To minimize filament tension:
- Install a bearing-based spool holder to ensure smooth rotation (like this or this)
- Mount your filament above or behind the centre of the print area to maintain consistent tension across the entire print volume
- Ensure your spool can rotate with minimal resistance
3. Prevent Nozzle Catches
Layer shifts often occur when the nozzle catches on the print, particularly with sticky materials like PETG. This is most likely to happen if the part starts warping.
To prevent nozzle catches:
- Ensure proper bed adhesion to minimize warping.
- Check that your first layer height is correctly calibrated. If the first layer is too low, a rough first layer could cause the nozzle to get caught. See our article about fixing a low first layer on MK4.
Credit: u/A_genuine_idiot on Reddit - Adjust your extrusion multiplier. If you are getting rough top surface layers, the nozzle can get caught on those as well. Turn down the extrusion multiplier in PrusaSlicer if your parts look like this:
Credit: u/Stuckinfemalecloset on Reddit 
- Enable Z-hop in your slicer so that the nozzle has more of an opportunity to dodge the part and avoid risk of collisions during fast travel moves
4. Optimize Speed and Power
The MK4's default profiles can sometimes over-estimate the strength of the motors. We've found that reducing print speed and acceleration in PrusaSlicer often provides more reliable results, especially for larger prints or when using materials like PETG.
The motors can overheat if they are in a suboptimal environment. Environmental considerations for optimal performance:
- Monitor ambient temperature around your printers.
We recommend running printers at an ambient temperature of 25C or lower, this both provides sufficient cooling for the motors but also is typically the temperature that print profiles are calibrated for, and will result in the best print quality. - Ensure good ventilation around stepper motors.
- Consider additional cooling for motors if printing in a warm environment.
- Avoid enclosing the printer unless specifically needed for your material.
5. Advanced Motor Settings
For those printing very heavy parts or running at high speeds, there's an advanced solution available. The MK4 doesn't run its motors at full power by default, but you can increase their power with a simple G-code command:
Important considerations:
- Only use this if other solutions haven't resolved the issue
- Monitor motor temperatures more closely
- Be prepared to add additional cooling if needed
- Return to default values if you notice excessive motor heat
The Result
By implementing these solutions, we've achieved reliable high-speed printing on Prusa MK4. The key is understanding that layer shifts aren't random – they're the result of specific conditions that can be identified and addressed. Whether you're printing with heavy spools, sticky materials like PETG, or just pushing your printer to its speed limits, these solutions should help you maintain consistent, shift-free prints.
Looking for more MK4 solutions? Check out our previous posts on fixing mid-air printing, nozzle oozing, and first layer issues.
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