DEV Community: La Primera Capa

3D printing problems by symptom: a field guide to what the print is telling you

La Primera Capa — Wed, 11 Nov 2026 12:56:44 +0000

A print problem is read from the part itself: it lifts off the bed, material is missing or in excess, layers shift or separate, marks appear on the surface, or the supports fail. Each defect points to its own causes. This guide groups them by what you see and says where to start. Where a defect has its own guide, the link goes there.

The part lifts off the bed, or the first layer is wrong

Corners lift while the part grows, or it never sticks. Warping and poor adhesion are told apart by when they show up. Warping lifts the corners as the part grows, because the plastic contracts as it cools, and Prusa ties it mostly to high-temperature materials such as PC Blend, ASA or ABS. If the part does not stick from the first layers, the problem is usually adhesion, for example grease or residue on the plate. Full guide on warping and parts that lift.

The part sticks but the first layer comes out wrong. Lines that do not join, gaps between them or squashed lines usually trace back to the distance between nozzle and plate. Full guide on bad first layers.

Too much filament, or not enough

Nothing comes out, or too little. The cause can be the nozzle, the extruder, the temperature or the filament path. Full guide on printers that do not extrude.

Over-extrusion. The printer lays down more material than planned along the whole part, and the walls come out rough and uneven, with layers that look thicker or squashed. Creality lists a flow rate that is too high, a temperature that is too high and an incorrect filament diameter, in that order. To correct the flow, lower it a little at a time, but the manufacturers disagree on the step: Creality suggests 2 to 5% each time, Anycubic 5 to 10%. Both suggest lowering the temperature in 5 °C steps, and Creality says to measure the real filament diameter with calipers and match it in the slicer.

Layers shift, separate or ripple

Shifted layers. From one layer up, the part sits offset, as if pushed mid-print. A belt tension that is wrong or loose pulleys are among the usual suspects. Full guide on layer shifting.

Cracks or layers that separate. Bambu Lab describes cracks along the Z direction when interlayer adhesion is insufficient and shrinkage is significant, common with ABS, ASA, PC, PET-CF and PA-CF. Prusa says layer separation is mostly caused by an incorrect profile with the wrong temperatures, or too much cooling from the print fan or the surrounding environment. Bambu Lab's improvement methods start with unclogging the nozzle, because a slight clog can interrupt extrusion in one layer and look like a crack. After that: raise the nozzle temperature appropriately or lower the speed, reduce the part cooling fan, and raise the bed by 5 to 10 °C. For ABS, Prusa suggests turning the fans off and printing in an enclosed chamber.

Waves along the whole height (Z banding). Unlike a sudden shift, the defect repeats along the part in bands. Anycubic says Z wobble and inconsistent extrusion are the two main reasons. On the mechanical side it lists checking the Z-axis stepper motor mount, the lead screw (a bent one should be replaced) and the rod coupler. On the extrusion side it lists a clean nozzle and a stable temperature. Polymaker adds that a tall, thin part can wobble, mostly on printers whose bed moves back and forth.

Marks, strands or blobs on the surface

Strands between parts. Fine, cobweb-like strands appear when molten filament keeps seeping out while the head travels from one area to another. Wet filament, retraction, temperature and nozzle condition are the usual causes. Full guide on stringing.

Dots or blobs. These are localized defects, scattered over the surface, while over-extrusion affects the whole part. Bambu Lab says the most common reason for random dots is the seam position set to Random, which in Bambu Studio you change to Aligned or Back. Its second cause is moisture, and it recommends drying all filaments before printing, new spools included.

Ghosting. Prusa says ghosting is typically recognized by several waves that follow after a sharp edge of a model. Creality traces it to tiny mechanical vibrations when the printhead makes sudden turns. Anycubic and Creality list high speed, acceleration and jerk, loose belts or screws and an unstable base. Prusa starts with the X and Y belts, which should be tight enough to sound like a low bass note when plucked, and adds that ghosting can show even with properly tightened belts, because vibrations increase with print speed: reduce the speed and put the printer on a firm surface.

Supports fail or damage the part

Prusa says that if a support breaks, it is likely to cause a failure on the whole print. To prevent it, it suggests avoiding isolated or scarce support towers, reducing the printing speed for supports and using a brim around the support. It also says the default rectilinear pattern is the easiest to remove, while the rectilinear grid is sturdier and less prone to breaking during printing. After printing, Bambu Lab recommends removing supports within 2 hours of the print finishing, especially for moisture-prone PA-type filaments such as PA-CF.

If the problem persists

If the problem is still there, Bambu Lab recommends submitting a support ticket that includes your recent printer logs and pictures or other details. Prusa suggests sending the model to its customer support when a support problem is very particular.

Sources

Everything above comes from the manufacturers' own documentation:

Prusa, guides on warping, ghosting, failing supports and layer separation, Prusa Knowledge Base (consulted 03/11/2026 and 11/11/2026).
Bambu Lab, "Dots on the print", "Model interlayer cracking" and "Removing supports and potential print damage", Bambu Lab Wiki (consulted 04/11/2026 and 11/11/2026).
Creality, "3D printing: under, over and not extruding" and "3D printer ringing and ghosting", Creality blog (consulted 04/11/2026 and 11/11/2026).
Anycubic, "3D printer over-extrusion" and "Fix Z banding / wobble", Anycubic blog (consulted 04/11/2026 and 11/11/2026).
Polymaker, "Z-Axis Wobble", Polymaker Wiki (consulted 04/11/2026 and 11/11/2026).

The full version, in Spanish, is at laprimeracapa.es.

Stringing in 3D printing: wet filament, retraction and travel moves

La Primera Capa — Wed, 11 Nov 2026 12:56:09 +0000

Stringing is the cobweb of thin strands left between separate parts of a print, or on its surface. Bambu Lab describes it as thin filaments unintentionally pulled out when molten filament seeps from the nozzle during travel moves. Oozing is a related defect: material keeps seeping out when the nozzle should not be extruding, and it piles up on the part or the nozzle. Bambu Lab says the two usually share causes, mostly excessive extrusion at the nozzle, damp filament or improper retraction settings.

Read the symptom first

What you see	What to check first
Thin strands between separate parts	Retraction, temperature, the distance between the areas being printed
Strands with popping or hissing during extrusion	Whether the filament is wet
Blobs or buildup on the part or the nozzle	Temperature and the state of the nozzle

Why strands appear

Wet filament

Polymaker says that if you hear pops or sizzling while extruding, that is water vapor escaping, and that wet filament creates stringier prints because steam causes inconsistent extrusion and little wisps between parts. Bambu Lab explains the mechanism: the moisture vaporizes when heated and the molten material bursts and flows abnormally. For Bambu Studio, it adds that damp filament is more prone to stringing and oozing, and that this usually cannot be fully solved by adjusting retraction alone: dry the filament first, then adjust retraction.

Retraction and travel moves

Between one area of the part and another, the head travels without printing. To limit the flow on that trip, the slicer pulls back some filament, which is retraction. If retraction is too short, molten material keeps coming out during the trip and can leave a strand along the way. Parts with separate areas are more prone to strands, and so are several parts spread across the bed, because the head covers more distance without printing. Bambu Lab lists long travel distances with insufficient retraction as the second cause after damp filament. The right value depends on the extruder type, the material and the printer.

Nozzle temperature

Bambu Lab says an excessively high nozzle temperature reduces the viscosity of the molten material and leads to abnormal extrusion. Prusa also lists a high temperature among the causes.

The nozzle itself

Prusa says that if you print for a long time with one type of filament, such as PET-G, the filament can leave a thin layer in the nozzle, which can cause stringing, so it recommends cleaning the nozzle thoroughly before printing. Bambu Lab adds that a nozzle that is too large, or worn, is another cause, and recommends a configuration that matches the real nozzle and replacing a worn one.

The material

Polymaker says PETG is known for being stringy, so it will be difficult to get rid of all of it. Flashforge adds that stringing alone does not prove PETG is wet, because nozzle temperature, travel speed, retraction and cooling can create similar defects. Bambu Lab lists low-density filaments such as PLA Aero as another cause: they contain internal voids and gases, including moisture, and if the temperature and flow ratio are not lowered they string more.

What to try

Start with the profile recommended for your printer and filament. On Prusa printers those are the official PrusaSlicer profiles.

If strings remain with that profile, try a different spool than the one causing the problem. That is Prusa's suggestion, because the filament might have gathered moisture, and Flashforge suggests drying it or replacing it with a newly unpacked filament. If the strands disappear with another spool, dry the first one before touching any setting. Bambu Lab recommends drying the filament before printing and storing it in a sealed container with desiccant.

Once the spool is dry, what remains is retraction, temperature and travel moves. Change them in small steps and check the result before the next change.

On retraction, you can raise the length or the speed a little, up to a limit, because too much can cause clogs. Bambu Lab generally recommends keeping the length no greater than 2 mm. Prusa gives a maximum of 2 mm for the MK2.5/S and MK3/S/+, while the MINI, which has a Bowden extruder, defaults to 3.2 mm. Those values belong to the models named, so for another printer use the manufacturer's documentation.

On temperature, Prusa and Creality suggest lowering the nozzle temperature by 5 to 10 °C, within the range recommended for the filament.

On travel moves, Bambu Lab suggests reducing the spacing between models and enabling "Avoid crossing wall". Prusa has the equivalent "Avoid crossing perimeters" and "Only retract when crossing perimeters".

Removing strings from a finished print

Prusa suggests passing a heat gun set to about 200 °C over the strings for one or two seconds to melt them, and warns that leaving the heat source on the model for longer may deform the part.

Sources

Everything above comes from the manufacturers' own documentation:

Prusa, "Stringing and oozing", Prusa Knowledge Base (consulted 04/11/2026 and 11/11/2026).
Bambu Lab, "Stringing and oozing" and the Bambu Studio retraction parameters, Bambu Lab Wiki (consulted 04/11/2026 and 11/11/2026).
Polymaker, "Wet Filament" and "Polymaker Material Print Tips", Polymaker Wiki (consulted 04/11/2026 and 11/11/2026).
Flashforge, "PETG drying temperature", Flashforge blog (consulted 04/11/2026 and 11/11/2026).
Creality, "3D Print Retraction Guide: Fix Stringing & Improve Quality", Creality store blog (consulted 04/11/2026).

The full version, in Spanish and with compatible parts for specific printers, is at laprimeracapa.es.

Print lifting off the bed: warping or a first layer that never stuck?

La Primera Capa — Wed, 11 Nov 2026 12:55:33 +0000

Warping and poor adhesion can both lift a part off the bed, but they have different causes, and a fix for one may do nothing for the other. Before changing anything, work out which one you have.

Read the symptom first

If the corners or edges start to lift while the part grows, it can be warping. If the first layer does not stick from the start, or the base starts to come loose in the first layers, it is an initial adhesion problem. These signs help separate the two, though they are not always enough on their own.

What you see	What to check first
Corners lift while printing	The material, the bed temperature, drafts around the printer
The base never sticks to the plate	Plate cleanliness, the plate selected in the slicer, nozzle distance

Why the part comes loose

Shrinkage and temperature

Prusa explains warping as usually the result of a sudden difference between the melting temperature at the nozzle and the ambient temperature. The plastic shrinks and warps, mostly with high-temperature materials such as PC Blend, ASA or ABS, and on large objects. Creality's table rates the risk as low for PLA, medium for PETG and high for ABS, and suggests avoiding strong cooling fans with PETG.

The room matters too. Prusa says an open window or an AC unit near the printer will increase the occurrence of warps.

Initial adhesion

Here the part never gets stuck. Flashforge lists oil stains on the build plate, a damaged or worn plate and an improper nozzle distance after leveling as causes. On Bambu Lab printers there is a common one on top of that: picking a plate type in the slicer that is not the one installed. Bambu Lab notes that the same material is usually printed at different bed temperatures depending on the plate, so the wrong selection can leave the adhesion short.

What to try, simplest first

Start with the cheap checks before changing print settings or parts. You do not need all of them, only the ones that match your problem.

Clean the plate the way its maker says. Bambu Lab strongly recommends washing its plates with hot water and detergent before printing, without touching the surface afterwards. For its steel sheets, Prusa gives isopropyl alcohol of 90% or more for smooth, satin and textured ones, warm water with dish soap when adhesion fades over time, and acetone only on smooth PEI, about once a month. It says never to use acetone on textured or satin sheets.

Check the plate is right and that the slicer knows it. Two checks: the surface suits the material, and the plate type chosen in the slicer matches the one installed.

If the part still will not stick, consider glue stick. Try a brim first, covered below. A glue stick can do two jobs: help the part stick, or act as a separation layer when a material grips so hard it could damage the plate. Prusa says a thin layer of glue stick applied to the cold steel sheet can do both. It recommends a separating agent for PETG, ABS, ASA, XT and CPH on smooth PEI, says it is not needed for PLA in its experience, and says it may be advisable for nylon, PETG, PC, ABS and ASA. Prusa also says: do not put super glue on your sheet.

Check leveling and the first layer. Follow the manufacturer's leveling procedure and make sure the nozzle distance lets the first layer lay down properly. Do not squash it too much either: Prusa notes that with PETG or PC, adhesion can get strong enough to damage a PEI sheet.

Match the bed temperature to the filament. Use the range your filament maker publishes, within the limits of your printer and plate. Prusa suggests raising the bed by 5 to 10 °C with new materials that do not stick, and Creality gives roughly 50 to 60 °C for PLA and 90 to 110 °C for ABS, as general figures. Those are not universal values. The bed temperature is not the chamber temperature.

Print the first layer slower. Prusa suggests about 75% of normal speed for the first three layers. The right value depends on the printer and the material.

If the edges lift, try a brim. A brim is a set of lines the slicer prints around the base to widen its contact area with the plate. Prusa says to consider the brim before adding extra adhesion materials to the bed.

For ABS and ASA, consider an enclosed printer. Prusa says high-temperature materials generally need a higher ambient temperature not to warp, and that if you print them most of the time you should consider an enclosure. It adds that printing PLA or PETG in an enclosure might not be a good idea, because those materials need a lot of print cooling, which is harder to achieve with a higher ambient temperature. Creality also suggests enclosing the printer to keep temperatures uniform and avoid drafts.

Sources

Everything above comes from the manufacturers' own documentation:

Prusa, "Warping" and "First layer issues", Prusa Knowledge Base (consulted 03/11/2026 and 11/11/2026).
Bambu Lab, "First layer not sticking", Bambu Lab Wiki (consulted 03/11/2026 and 11/11/2026).
Creality, "3D Print Warping: What Causes It, How to Fix It, and How to Prevent It", Creality blog (consulted 03/11/2026 and 11/11/2026).
Flashforge, "Troubleshooting: Equipment Usage Issues" for the Adventurer 5M, Flashforge documentation (consulted 03/11/2026).

The full version, in Spanish and with compatible parts for specific printers, is at laprimeracapa.es.

A bad first layer in 3D printing: nozzle height, bed surface and how to test it

La Primera Capa — Wed, 11 Nov 2026 12:54:58 +0000

The first layer is the base everything else is built on, and Prusa calls problems with it the most common 3D printing problem and probably the first one you will meet. A first layer can stick to the bed and still be wrong: separate lines, squashed areas, differences from one zone to another, or a base wider than the rest of the part. Each defect has several possible causes, from the cleanliness of the bed to the height of the nozzle.

What a good first layer looks like

Bambu Lab describes it as smooth, uniform and well adhered, with clean lines that overlap without ridges or air gaps.

What you see	What to check first
Thin, wavy or separated lines	A dirty bed, and whether the nozzle is too high
Very squashed layer, raised edges or drag marks	Whether the nozzle is too low; on the Bambu Lab A1, also the screws of the heater assembly
Good in some areas, bad in others	Dirt in those areas, then the automatic bed calibration
No material comes out when the print starts	Whether the nozzle is too low, or a clog
The base is wider than the rest of the part	Z offset, bed temperature, and too much material in the first layer

Dirty bed

Fingerprint grease and other residue can keep the filament from sticking evenly. For its steel sheets, Prusa recommends isopropyl alcohol of 90% or more as the best degreaser, and notes that skin or nail products can contain additives such as moisturizers and oils. If adhesion seems to fade even with alcohol, it says you can wash the sheet with a few drops of dish soap and warm water (not too hot), though not often. It also says there is no need to clean the sheet before every print if you have not touched it with your hands.

Nozzle too high or too low

Bambu Lab's rule of thumb: if the layer barely sticks or comes out thin and wavy, the nozzle is too high. If it is so squashed that it raises edges or the nozzle drags, it is too low. That height is set by the Z offset, the position of the nozzle relative to the bed, and one cause of a wrong value is not having leveled the bed, especially after changing the plate. Bambu Lab says to level automatically first and leave manual leveling as the last resort.

Each manufacturer handles the adjustment its own way. On the MK2 and MK3, Prusa uses Live Z adjustment inside its first layer calibration. For the A1, Bambu Lab documents a temporary G-code adjustment, with values specific to that model, and says it is only a quick temporary fix: afterwards, go back to the default and focus on leveling.

If the nozzle is too low, Prusa notes that the printer may not extrude plastic for the first layer or the first two.

Screws in the toolhead (Bambu Lab A1)

On the A1, a first layer that is too low can also mean the hotend has shifted relative to the leveling. Bambu Lab's procedure: with the printer off and the hotend removed, retighten the three mounting screws of the heater assembly with an H2.0 hex key and the four small ones on the back with an H1.5.

Speed and temperature

With nozzle height checked, speed and temperature come next. Prusa suggests lowering the speed to about 75% for the first three layers. For new materials that do not stick well, it suggests raising the bed temperature by 5 to 10 °C.

Clogged nozzle

A total or partial clog can also ruin the first layer. Prusa lists it among the causes in its first layer guide.

Uneven or damaged surface

A nozzle set too low can damage the steel sheet, and some surfaces have irregularities that mesh leveling does not compensate. For that, Prusa gives a temporary fix, a sheet of paper under the uneven area of the sheet, and a more permanent one, the bed leveling correction in the firmware.

Wide base (elephant foot)

Creality defines elephant foot as a defect at the bottom of a print where the first layer or layers are wider or bulged out compared to the rest of the part. Its listed causes include a Z offset that is too low, a bed that is too hot and too much material in the first layer. Its fixes: raise the Z offset by 0.05 to 0.1 mm, lower the bed temperature in small steps (for example 5 degrees), and check the amount of material in the first layer. Cura also has "Initial Layer Horizontal Expansion", and a small negative value prints the first layer inside the boundaries of the model.

How to run a first layer test

Bambu Lab's suggestion is to print a cube 0.2 mm thick scaled to fit the bed, so that the result is a single layer. Before printing it, the page lists: wash the plate, check the nozzle and screws, run the automatic calibration, use dry filament and lower the first layer speed. A good result leaves uniform lines without gaps, a continuous surface without ridges or drag marks, and a layer without raised edges. If one area comes out worse than the others, clean the plate and repeat the automatic leveling before turning to manual.

What not to do

Prusa warns against compensating for poor adhesion with a lower Live Z value, squashing the first layer: go too low and the nozzle can damage the steel sheet. It also says not to put super glue on the sheet and never to use acetone on textured or satin powder-coated sheets.

Sources

Everything above comes from the manufacturers' own documentation:

Prusa, "First layer issues", Prusa Knowledge Base (consulted 04/11/2026, read again 11/11/2026 in its Spanish version).
Bambu Lab, "Identify and fix first layer issues with a test print", Bambu Lab Wiki (consulted 04/11/2026).
Bambu Lab, "Print issues troubleshooting" for the A1 mini, section "First layer too low", Bambu Lab Wiki (consulted 04/11/2026).
Creality, "3D Printer Elephant Foot", Creality blog (consulted 04/11/2026).

The full version, in Spanish and with compatible parts for specific printers, is at laprimeracapa.es.

3D printer not extruding: what to check, from cheapest to most work

La Primera Capa — Wed, 11 Nov 2026 12:54:22 +0000

Under-extrusion means less filament reaches the part than the layers need. In the worst case nothing comes out even though the extruder motor keeps turning. Before changing any slicer setting, it helps to sort what you see into one of four cases, because each one points to a different place.

Read the symptom first

What you see	What to check first
Nothing comes out when the print starts	Nozzle temperature, the path of the filament, a blocked nozzle
Less material than expected, gaps between lines	A partial clog, the extruder gears, extrusion conditions
The extruder clicks or the filament does not move	Resistance in the feed mechanism or on the way to the nozzle
The print starts fine and extrusion stops later	The spool, the filament path, possible heat creep

A clicking extruder is worth taking seriously. Prusa explains it as the stepper motor suddenly having to push harder than a preset threshold. It tells you the motor found resistance, not where the resistance is.

Blocked nozzle

Anycubic calls a clogged nozzle the most common cause of filament not coming out. The blockage can be partial or total, and material can also jam above the nozzle, inside the hotend.

Bambu Lab proposes a quick test with PLA: set the nozzle to 220 °C, load the filament and press extrude. If the filament drops vertically, comes out relatively long and looks smooth, the nozzle channel is clear and the drive gear is normal. If it is short and rough, the channel is narrowed or the gear is at fault. The number and the test belong to Bambu Lab, so on another machine start from that manufacturer's instructions.

The first remedy is to push filament through a hot nozzle. Prusa's procedure: heat it to 260 °C if you have been using PLA, or 280 °C for higher-temperature materials such as PETG or ASA, wait two minutes and push. If nothing flows, Prusa suggests the nozzle probably needs replacing, and a cold pull is unlikely to work where this failed.

For nozzles that are not high-flow, Prusa also describes an acupuncture needle or a thin wire (0.3 to 0.35 mm) pushed in from below, 1 to 2 cm, and says to wear protective gloves because material can suddenly start to flow. Bambu Lab warns that using a needle may release the internal pressure of the hot end, so it says to wear gloves and not lean over the machine.

If the clog is only partial and some filament still comes out, the usual next step is a cold pull: a filament is pushed in at printing temperature, cooled, and pulled out to drag residue with it. Prusa says it works best with PLA, that you pull straight up and not sideways, and that you should not stop until the filament is completely out. Creality describes what a good result looks like: the tip reproduces the inside of the nozzle, sometimes with dark specks or residue attached. The cooling temperature differs from one manufacturer to another, so use the one in your printer's guide.

The extruder

When the extruder clicks or the filament comes out ground down, the problem can be in the mechanism that pushes it. The manufacturers list debris in the feed gear, a worn or misaligned gear, a motor with too little force and badly set tension. On the Bambu Lab A1 series, the wiki says to take the extruder apart and check that the motor turns smoothly and that the yellow gear is not worn or missing teeth. For other printers, follow the manufacturer's own steps.

Temperature and speed

A nozzle colder than the material needs makes extrusion harder. Creality suggests raising the temperature in 5 °C steps, without leaving what the filament and the printer allow. At high speed the filament may not melt in time. For its high-speed mode, Bambu Lab recommends raising the nozzle temperature by about 10 °C.

Heat creep

Prusa describes it this way: the printer suddenly stops extruding but keeps making the print moves, without reporting any error. Heat travels up the hotend and melts the filament before it reaches the melt zone. Prusa lists a warm room or an enclosure, PLA, a hotend temperature set too high and too little air over the heatsink among the most common causes. Its checks: the heatsink fan must push air inside, not outside, and PLA in a fully closed, unventilated enclosure is very likely to cause problems. Creality suggests better cooling, a lower temperature and a higher speed as ways to reduce it.

Spool and filament path

The simplest check is that the filament leaves the spool without tangles or obstacles. If your printer guides the filament through a PTFE tube, check that it is seated and undamaged.

Wet or uneven filament

Prusa notes that the industry standard for variation in filament diameter is plus or minus 0.05 mm, and lists degraded or wet filament among the causes of clogs and under-extrusion.

What not to do

Prusa says not to heat the nozzle with an external heat source, because it can damage it, and to take the extruder gearbox apart only with the printer cold and switched off. It also warns against touching the hotend when it is hot, as heated parts can cause severe burns. Bambu Lab says to wear an oven glove when the hotend has to be held.

When to contact the manufacturer

If these checks do not solve it, Bambu Lab recommends submitting a support ticket and including pictures or other details of the problem.

Sources

Everything above comes from the manufacturers' own documentation:

Prusa, "Clogged nozzle", "Under-extrusion", "Extrusion stopped mid-print (Heat creep)", "Cold pull" and "Extruder noises", Prusa Knowledge Base (consulted 04/11/2026).
Bambu Lab, "3D Printer Clog", "Under-Extrusion", and the A1 and H2S nozzle clog pages, Bambu Lab Wiki (consulted 11/11/2026).
Creality, "Filament Not Coming Out of Nozzle", "Cold Pull 3D Printing" and "Heat Creep", Creality blog and store (consulted 04/11/2026).
Anycubic, "Filament Not Coming Out of 3D Printer", Anycubic blog (consulted 04/11/2026).

The full version, in Spanish and with compatible replacement parts for specific printers, is at laprimeracapa.es.

Layer shifting in 3D printing: what to check, in the order that saves time

La Primera Capa — Wed, 11 Nov 2026 12:44:15 +0000

A layer shift looks like a step in the print: from a certain height, everything above sits offset from what is below. It happens when an abnormal movement on the X axis, the Y axis or both pushes one or several layers out of position. Before touching any setting, two questions are worth answering. Which axis moved, and did it happen once or several times?

Read the symptom first

A single shift is usually an interference during the print, such as tangled filament or a cable in the path of an axis. Several shifts point to the belts, the pulleys, the bearings, the rods, the acceleration or the motors.

What you see	What to check first
One shift	Whether something got in the way of the head or the bed: cables, tubes, tangled filament
Several shifts	Belt tension and how the pulleys are fixed
Always at the same height	A local obstacle and, if it involves Z, the lead screw
Shifts that show up on fast moves	Speed and acceleration
The nozzle touches the part mid-print	Whether the part curled upward or filament is sticking to the nozzle

Belts: too loose, or too tight

Move the axes by hand with the printer cold and powered off. If the motion on X or Y is not smooth and even, start with the belt, which along with loose pulleys is among the most frequent causes of shifts.

The belt should be firm without being over-tightened, because excess tension causes problems too. Anycubic warns that excessive tension has damaged motors and caused lost steps. Prusa gives an acoustic reference for its open-belt printers: pluck the belt and it should sound low, like a bass string. Bambu Lab publishes its own belt tensioning procedure for each model (A1, A1 mini, X1/P1, H2D) on its wiki, so follow the one for your machine. If the belt is worn, check the manufacturer's documentation to see whether it should be replaced.

Pulleys and grub screws

On many printers the pulley is fixed to the motor shaft with grub screws. One of them has to sit on the flat part of the shaft. If it is tightened without checking, the fix is temporary and the shift comes back. If the shift appears diagonally when you move the axes by hand, the problem can be in the motor that drives that diagonal or in its pulley.

Obstacles and friction

When something in the path of the head or the bed resists with more force than the motor can apply, the motor skips steps and the part ends up offset. The usual suspects: filament piling up in the purge chute during color changes, damaged cables, badly routed tubes, blocked guides, and a Z lead screw that is dirty or dry.

Check the smooth rods for deep scratches, and keep the bearings lubricated. Clean the rods with paper before applying lubricant. A general-purpose lithium grease works, though the important part is using a lubricant that suits your printer and applying it only where the manual says to.

If the nozzle rubs the part, the cause can be a part that curled upward or a very viscous filament sticking to the nozzle. When the curling starts at a corner that lifts, that is a warping and bed adhesion problem, and drying the filament or enabling the purge tower helps.

Speed, acceleration and jerk

Too much speed or acceleration can cause shifts, especially when both are combined with a high jerk (the abrupt change of speed at the start of a move). Bambu Lab notes that switching to a very fast mode such as Ludicrous in the middle of a print can be enough to shift layers, and it offers an option called "Auto-recovery from step loss" meant to handle lost steps automatically. For large objects on the Prusa MINI, Prusa recommends lowering the speed.

Motors and electronics

An overloaded motor, or drivers that run too hot, will also lose steps. On Prusa printers, normal power mode is preferable to silent mode when printing large or complex parts.

Slack in the carriage, the bed and the Z axis

Small shifts that repeat, sometimes on every layer, tend to come from the structure of the machine and not from the settings: a loose carriage or hotend, worn bearings or wheels, play in the bed, bent Z rods. On the Z axis, a bent lead screw and the coupler that joins it to the motor also matter.

What not to do

Do not tighten the pulley grub screw without checking that it seats on the flat of the shaft. Do not over-tighten the hotend while it is hot, because the heater block, the nozzle or the heat break can break.

When to contact the manufacturer

Print the printer's own test model first. If it shows no shift, review the slicer configuration used for the original part. If the shift continues after these checks, contact the manufacturer's support or the shop where you bought the machine. Include the printer model, the firmware version, the affected axis and the layer where it happens, with photos or a video.

Sources

Everything above comes from the manufacturers' own documentation:

Prusa, "Layer shifting", Prusa Knowledge Base (consulted 04/11/2026).
Bambu Lab, "Layer Shift: Causes and Solutions", Bambu Lab Wiki (consulted 04/11/2026).
Bambu Lab, belt tensioning guides for the A1, A1 mini, X1/P1 and H2D, Bambu Lab Wiki (consulted 11/11/2026).
Creality, "Why Your 3D Prints Are Layers Shifting? How to Fix It Fast", Creality blog (consulted 04/11/2026).
Anycubic, "Layer Shifting Troubleshooting" for the Kobra X, Anycubic Wiki (consulted 04/11/2026).
Polymaker, "Layer Shifts" and "Z-Axis Wobble", Polymaker Wiki (consulted 04/11/2026).

The full version, in Spanish and with compatible parts for specific printers, is at laprimeracapa.es.