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3D printing stringing problem


Stringing or Oozing

Stringing or Oozing

Stringing (otherwise known as oozing, whiskers, or “hairy” prints) occurs when small strings of plastic are left behind on a 3D printed model. This is typically due to plastic oozing out of the nozzle while the extruder is moving to a new location. Thankfully, there are several settings within Simplify3D that can help with this issue. The most common setting that is used to combat excessive stringing is something that is known as retraction. If retraction is enabled, when the extruder is done printing one section of your model, the filament will be pulled backwards into the nozzle to act as a countermeasure against oozing. When it is time to begin printing again, the filament will be pushed back into the nozzle so that plastic once again begins extruding from the tip. To ensure retraction is enabled, click “Edit Process Settings” and click on the Extruder tab. Ensure that the retraction option is enabled for each of your extruders. In the sections below, we will discuss the important retraction settings as well as several other settings that can be used to combat stringing, such as the extruder temperature settings.

Common Solutions

Retraction distance

The most important retraction setting is the retraction distance. This determines how much plastic is pulled out of the nozzle. In general, the more plastic that is retracted from the nozzle, the less likely the nozzle is to ooze while moving. Most direct-drive extruders only require a retraction distance of 0.5-2.0mm, while some Bowden extruders may require a retraction distance as high as 15mm due to the longer distance between the extruder drive gear and the heated nozzle. If you encounter stringing with your prints, try increasing the retraction distance by 1mm and test again to see if the performance improves.

Retraction speed

The next retraction setting that you should check is the retraction speed. This determines how fast the filament is retracted from the nozzle. If you retract too slowly, the plastic will slowly ooze down through the nozzle and may start leaking before the extruder is done moving to its new destination. If you retract too quickly, the filament may separate from the hot plastic inside the nozzle, or the quick movement of the drive gear may even grind away pieces of your filament. There is usually a sweet spot somewhere between 1200-6000 mm/min (20-100 mm/s) where retraction performs best. Thankfully, Simplify3D has already provided many pre-configured profiles that can give you a starting point for what retraction speed works best, but the ideal value can vary depending on the material that you are using, so you may want to experiment to see if different speeds decrease the amount of stringing that you see.

Temperature is too high

Once you have checked your retraction settings, the next most common cause for excessive stringing is the extruder temperature. If the temperature is too high, the plastic inside the nozzle will become less viscous and will leak out of the nozzle much more easily. However, if the temperature is too low, the plastic will still be somewhat solid and will have difficulty extruding from the nozzle. If you feel you have the correct retraction settings, but you are still encountering these issues, try decreasing your extruder temperature by 5-10 degrees. This can have a significant impact on the final print quality. You can adjust these settings by clicking “Edit Process Settings” and selecting the Temperature tab. Select your extruder from the list on the left, and then double-click on the temperature setpoint you wish to edit.

Long movements over open spaces

As we discussed above, stringing occurs when the extruder is moving between two different locations, and during that move, plastic starts to ooze out of the nozzle. The length of this movement can have a large impact on how much oozing takes place. Short moves may be quick enough that the plastic does not have time to ooze out of the nozzle. However, long movements are much more likely to create strings. Thankfully, Simplify3D includes an extremely useful feature that can help minimize the length of these movements. The software is smart enough that it can automatically adjust the travel path to make sure that nozzle has a very short distance to travel over an open space. In fact, in many cases, the software may be able to find a travel path that avoids crossing an open space all together! This means that there is no possibility to create a string, because the nozzle will always be on top of the solid plastic and will never travel outside the part. To use this feature, click on the Advanced tab and enable the “Avoid crossing outline for travel movement” option.

Movement Speed

Finally, you may also find that increasing the movement speed of your machine can also reduce the amount of time that the extruder can ooze when moving between parts. You can verify what movement speeds your machine is using by clicking on the Speeds tab of your process settings. The X/Y Axis Movement Speed represents the side-to-side travel speed, and is frequently directly related to the amount of time your extruder spends moving over open air. If your machine can handle moving at higher speeds, you may find that increasing this settings can also reduce stringing between parts.

Related Topics

5 Ways How to Fix Stringing & Oozing in Your 3D Prints – 3D Printerly

If you’re in the field of 3D printing, you might have come across an issue of strings of melted plastic or plastic oozing from your 3D prints. This is called stringing and oozing, which fits perfectly.

Fixing stringing and oozing is best done by having good retraction settings, where a good retraction length is 3mm and a good retraction speed is 50mm/s. You can also decrease your printing temperature to help filament be less runny, which reduces the instance of stringing and oozing.

It’s a fairly common problem that people experience which leads to poor quality prints, so you definitely want to get this fixed.

There are more details to know about so keep on reading the article to find out why this happens in the first place, and how to fix it once and for all.

What Causes 3D Prints to Have Stringing & Oozing?

Sometimes users try to print an object in which the nozzle has to move through an open area to reach the next point.

Stringing and oozing is the problem in which the nozzle extrudes the melted plastic while moving from an open space.

The melted plastic sticks between two points and look like attached strings or threads. To prevent or solve the problem, the first step is to find out the actual cause of the issue.

Some of the major causes behind the stringing and oozing problem include:

  • Retraction settings not being used
  • Retraction speed or distance too low
  • Printing with a temperature too high
  • Using filament which has absorbed too much moisture
  • Using a clogged or jammed nozzle without cleaning

Knowing the causes is a good way to start before getting into the solutions. The section below will take you through a number of ways how to fix stringing & oozing in your 3D prints.

Once you’ve gone through the list and tried them out, your problem should hopefully be solved.

How to Fix Stringing and Oozing in 3D Prints

Just like there are various reasons that cause stringing and oozing problems, there are also plenty of solutions that can help you fix and avoid it.

Most of the time this type of problem can be fixed just by changing some settings in the 3D printer such as extruder speed, temperature, distance, etc. It’s not ideal when your 3D prints are stringy so you want to get this sorted out quickly.

Below are some of the simplest and easiest solutions that can be implemented without requiring any major tools or techniques.

The methods that will help you to get rid of the problem for once and for all includes:

1. Print at a Lower Temperature

The chances of stringing and oozing increase if you are printing at a high temperature. The very first thing that you should do is to reduce the temperature and check for the results.

Reducing the temperature will help you because it will extrude less liquid material reducing the chances of stinging and oozing.

Those higher temperature materials are more prone to stringing because of the effects of higher heat on the viscosity or liquidity of filament.

Although PLA is a relatively low temperature material, it doesn’t mean it’s safe from stringing and oozing.

  • Reduce the temperature step by step and check if there are any improvements.
  • Make sure that the temperature is within the range required for the type of filament being used (should be on the filament packaging)
  • Try to use a filament that melts at lower temperatures efficiently like PLA
  • While reducing the printing temperature, you may have to lower down the extrusion speed because the filament material will take time to melt at low temperatures.
  • Do test prints of little objects to get an idea about the perfect temperature because different materials print well on different temperatures.
  • Some people will print their first layer 10°C hotter for good adhesion, then lower the printing temperature for the rest of the print.

2. Activate or Increase Retraction Settings

3D printers include a mechanism that works as a pullback gear called retraction, as explained in the video above. Enable retraction settings to pull back the semi-solid filament that is pushing the liquid to extrude from the nozzle.

According to experts, activating the retraction settings usually work to fix the stringing problems. What it does is relieve the pressure of the melted filament so it will not drip while moving from one point to another.

  • Retraction settings are activated by default but check for the settings if you are experiencing stringing or oozing.
  • Enable the retraction settings so that the filament can be pulled back every time the nozzle reaches an open space where printing is not designed or required.
  • A good retraction setting start-point is a retraction speed of 50mm/s (adjust in 5-10mm/s adjustments until good) and retraction distance of 3mm (1mm adjustments until good).
  • You can also implement a setting called ‘Combing Mode’ so it only travels where you have already printed, rather than in the middle of your 3D print.

I’d advise you to download and use this Retraction Test on Thingiverse, created by deltapenguin. It’s a great way to quickly test out how well in-tune your retraction settings are dialed in.

It really is hit or miss, high retraction settings of 70mm/s retraction speed and 7mm retraction distance works well, while others get good results with much lower.

3. Adjust Print Speed

Adjusting the print speed is a common factor to fix stringing, especially if you have reduced the printing temperature.

Reducing speed is necessary because with the reduced temperature the nozzle can start under extruding. After all, the filament will take more time to melt and become ready to extrude since it’s less runny.

If the nozzle is moving at a high speed, with a high temperature, and no retraction settings, you can bet you’ll experience stringing and oozing at the end of your 3D print.

  • Reduce the printing speed because this will mitigate the chances of leaking filament and causing stringing.
  • A good starting speed ranges from 40-60mm/s
  • A good travel speed setting is anywhere from 150-200mm/s
  • As different filaments take different time periods to melt, you should test the material by reducing the speed before starting your printing process.
  • Make sure that the printing speed is optimal because both too fast and too slow speed can cause problems.

4. Prevent your Filament from Moisture

Most 3D printer users knows that moisture affects the filament badly. Filaments absorb moisture in the open air and this moisture turns into bubbles when heated.

The bubbles usually keep on bursting and this process forces the dripping of the filament from the nozzle causing stringing and oozing problems.

The moisture can also become steam and will increase the chances of the stringing problems when mixed with the plastic material.

Some filaments are worse than others such as Nylon and HIPS.

  • Keep your filament stored and protected in a box or something that is totally airtight, with desiccant and has the ability to stop moisture from reaching the filament.
  • If suitable, try to use a filament which absorbs less moisture like PLA

I’d recommend going for something like the SUNLU Upgraded Filament Dryer from Amazon. You can even dry filament while you’re 3D printing since it has a hole that can feed through. It has an adjustable temperature range of 35-55°C and a timer that goes up to 24 hours.

5. Clean the Printing Nozzle

Whenever you print an object some particles of the plastic are left behind in the nozzle and with time get stuck in it.

This happens more so when you print with a high temperature material, then switch to a lower temperature material like from ABS to PLA.

You don’t want any kind of blockage in the way of your nozzle, since this is a very significant area for creating successful prints without imperfections.

  • Clean your nozzle thoroughly before printing to make it free from the residues and dirt particles.
  • Use a brush with metal wires to clean the nozzle, sometimes the common brush can also work well.
  • It will be better if you clean the nozzle every time you complete a print because it becomes easier to remove the heated liquid residues.
  • Clean your nozzle using acetone if you are printing after a long time.
  • Keep in mind that cleaning the nozzle is considered essential whenever you switch from one material to another.

After going through the above solutions, you should be in the clear for getting rid of that stringing and oozing problem that you have been experiencing.

It may be a quick fix, or it can require some trial and testing, but at the end of it, you know you’ll come out with some print quality you can be proud of.

Happy printing!

Problems, defects, 3D printing errors and solutions

Often during the operation of a 3D printer, problems may arise due to which defects appear on the finished model. Or instead of a neat product, plastic noodles suddenly appear on the table.

In fact, the causes of defects can be conditionally divided into 2 types - these are physical and software.

Physical ones are those that arise due to problems with the mechanics or any other causes that can be eliminated physically. These include problems with printer mechanisms (belt tension, backlash), clogged or deformed nozzle, incorrect table geometry, etc.

Software - these are defects that occur due to incorrect slicer settings or, less often, errors in the printer firmware. For example, incorrectly selected print speed, retract settings, incorrectly selected temperature for plastic, etc.

Very rarely, the problem may lie in the wrong or “flying” printer firmware (although usually the printer simply will not start then), overheating of some boards during printing, etc. These are rather special cases, so we will not consider them.

Model peels off or does not stick to the build plate

This is the most common 3D printing problem. Every 3D printer has had a case when the first layer treacherously rolls, clinging to the extruder, or the most offensive - when it tears off a partially printed model from the table. The first layer must stick tightly otherwise nothing will be printed.


Gap between table and nozzle 9 too large0023

This is the most common reason. You just need to set the correct gap between the table and the nozzle.

Modern printers often use an auto-calibration (auto-leveling) table system or an auxiliary table leveling program. To calibrate such printers, use the instructions. If there is no manual, it can be downloaded from the manufacturer's website.

If you have a simple printer without auto-calibration, a self-assembly or KIT kit, use a probe or a piece of paper folded in half to calibrate. The probe should be slightly pressed against the table by the nozzle. Before calibration, the table and extruder must be heated. Align the table surface over each adjustment screw (there may be 3 or 4) in turn, and only then check the center point.

If you're having trouble getting your table surface perfectly level, try raft printing. Raft is a thick substrate in several layers that is printed under the model. It will help smooth out the slight curvature of the table.


A small cheat sheet to determine the correct gap on the first layer

Plastic with poor adhesion

Some types of plastic, due to various reasons, such as large shrinkage, do not adhere well to the surface of the printing platform. In this case, try using stickers or special 3D adhesives to improve adhesion between the table and the first layer of plastic.

In the early days of 3D printing, there were experiments with different homemade 3D adhesive recipes. ABS diluted in acetone, BF glue, sugar syrup and even beer. Some experiments have been successful. Until now, some enthusiasts use some types of hairspray or glue sticks as 3D glue. But still they are inferior in their properties to industrial 3D adhesives.

Some types of high temperature plastics with a high percentage of shrinkage (ABS, Nylon, etc.) may peel off the table during printing. This is due to uneven cooling and “compression” of the model (the lower layers have already cooled down, but the upper ones have not yet). For such plastics, it is imperative to use a 3D printer with a heated table and a closed case.

Plastic temperature too low

The hotter the plastic is when it exits the nozzle, the better it will adhere to the print bed. It is better to print the first 5-10 layers at a higher temperature (+ 5-10 degrees) and turn off the blower fan.

Wrong first layer settings (speed and thickness)

A thicker layer sticks easier, so the standard first layer is 0.3mm thick. With an increase in print speed, the heating block may simply not have time to heat the plastic to the desired temperature and it will stick to the table worse. Before printing, check the speed and thickness settings of the first layer in the slicer.


A lot depends on how the 3D printer prints the first layer. Try to control the printing of the first layer and only then leave the printer to work alone.

Plastic does not choke from nozzle

The printer has already begun to print, but the print table remains empty. Or part of the model did not print.


Clogged nozzle

In 3D printing, a nozzle is a consumable. The nozzles are clogged or worn out (frequency depends on the type of plastic). The simplest thing is to replace the nozzle. But if there was no spare at hand, you can try to clean the old one. To do this, there is a whole set of thin needles. Or you can heat a clogged nozzle above the melting point of the plastic and “burn out” the blockage. But later it is still better to replace the nozzle.

Low temperature nozzle

You need to increase the temperature of the extruder in the slicer settings or check the thermistor and heating block. Sometimes the thermistor may not read the temperature correctly due to a malfunction or incorrect 3D printer firmware settings.

If the problem occurs after replacing the thermistor - contact the manufacturer or read articles about PID tuning.

Empty extruder

As the extruder heats up, plastic begins to ooze out of the nozzle. Because of this, the extruder may start printing half empty. Because of this, part of the first layer is not printed. You can push the plastic manually by simply pushing the bar into the nozzle. Or solve this problem programmatically - in the slicer, add a contour print around the model (one line).

Some manufacturers and 3D enthusiasts add a line print on the edge of the table at the beginning of each GCode. This is done so that there is plastic in the nozzle by the time the model is printed.

Feed mechanism does not push through plastic

The plastic pushes the feed mechanism to the extruder - a motor with a special pulley put on the shaft. If for some reason the plastic is not pushed through (nozzle clogged, extruder temperature low, etc.), then the pulley “gnaws” through the bar. You need to push the plastic bar with your hands or cut off the damaged piece.


Elephant foot

The first layers of the model are wider and protrude beyond the boundaries of the model. This is due to the fact that the upper layers put pressure on the first ones that have not yet cooled down and flatten them.


High table temperature

Due to the too high temperature of the table, the lower layers remain soft for a long time. Try lowering the table temperature. It is better to reduce gradually (in increments of 5 degrees). You can try to turn on the blower when printing the first layers.

Small gap between nozzle and platen

If, when printing the first layer, the nozzle is too close to the table, then excess plastic will be forced out. After a few coats, this will not be as noticeable, but can lead to the effect of an “elephant's foot”.


Plastic re-extrusion

When too much material is squeezed out of the nozzle, the walls of the model are not smooth, but bumpy, with sagging.


The solution is software - in the settings of the slicer, you need to set the material feed rate (fluidity) to a lower value. The average value is 95-98%.

It is worth checking the diameter of the rod. If its size is greater than 1.75, then the plastic will be squeezed out more than necessary.


Plastic underextrusion

The plastic is squeezed out too little, because of this, gaps may appear between the layer. The finished model will be fragile and fragile.


Wrong thread diameter

Check the filament diameter in the slicer settings. Sometimes, instead of the popular 1.75, the default is 2.85.

Incorrect feed factor settings

Check the fluidity settings in the slicer. The average should be 95-98%.

Clogged nozzle

Something could get into the nozzle and partially block the exit of the plastic. Visually, the plastic will choke from the nozzle, but in a smaller amount than necessary for printing.



Hairiness or cobwebs on finished model

Thin threads of plastic protrude from the outer wall of the model (most often on one side). The defect appears due to the flow of plastic from the nozzle during idle movement.


Insufficient retract

A retract is a slight pull of a plastic filament from an extruder. Due to the retract when the extruder is idle (from layer to layer or from model to model), heated plastic does not drip from the nozzle. For some flowable plastics (eg PETG) the speed and amount of retraction must be increased.

"Hairiness" can be easily removed by grinding or cutting off the threads with a sharp scalpel.

High temperature extruder

The higher the extruder temperature, the more liquid the plastic becomes. It is important to find a balance so that the plastic is not too liquid and sticks well in layers.

In the selection of the optimal extruder temperature, a test model - a tower - helps a lot. It clearly shows how plastic behaves when printed at different temperatures.

.

Temperature test

Top "perforated" or uneven

The top of the model is bumpy or with holes. The problem may arise if the top of the model is flat. For example, like a cube.


Insufficient airflow

When printing the top plane (cover), the plastic does not have time to cool down and remains too liquid. Because of this, the threads are torn and holes are formed. Increase the fan speed on the last layers.

Few top layers

The top of the print may be too thin and deform as a result. Check slicer settings. The number of upper layers is not recommended to be set less than 6.

Low percentage of filling

If the infill percentage is too low, then the top layer will simply have nothing to rely on. Increase the fill percentage in the slicer settings.

Model deformation

Some parts of the model seem to have melted in some places or on one side. The problem most often occurs when printing with PLA plastic. The defect appears due to the fact that the plastic does not have time to cool and deforms.


Insufficient airflow model

Turn the fans on to maximum. If their power is not enough (in some printers, the fan is located only on one side), you can put a regular desktop fan and direct it to the 3D printer table.

Small model

Small models are difficult to blow well. Try to print small items alongside larger ones, or place several identical models in different corners of the table. So the plastic will have more time to cool.

Layer offset

Layers shift along the x or y axis during printing.


Print head jam

Turn off the printer and try to move the extruder along the x and y axes with your hands. The extruder must move freely. If there are jams, check the mechanics of the printer. Bearing wear or the curvature of the shafts may be to blame.

Electronics overheating

Sometimes electronics problems can be to blame for misaligned layers. The most common cause is overheating of the drivers or too low current exposed to them.

Table top is loose

This is most often seen in 3D printers with glass. During printing, the nozzle may hit the model and move the glass slightly. Before printing, check if the glass or other printing surface is well fixed on the heating table.


Skip layers

Small holes are visible on the print, or the shell of the model is not continuous.


Teflon tube deformed

There are 2 types of thermal barriers - all-metal and with a Teflon tube. If overheated, the Teflon tube may deform. Plastic will pass through it, but in a smaller amount.

Low extruder temperature or high print speed

If the extruder is not heated enough, then the plastic will not be liquid enough and simply will not have time to be forced through the nozzle. The higher the print speed, the higher the extruder temperature should be.

Sometimes the outer walls print well, but the infill is “torn”. In this case, slow down the infill print speed in the slicer.

Model bundle

Cracks form on the surface of the printout during or after printing. Cracks can be large or very small. Most often, this problem occurs with plastics with a high percentage of shrinkage - ABS or Nylon.


Sudden temperature difference (if model delaminates during printing)

With a sharp temperature difference (for example, a draft), part of the model cools down faster. This leads to uneven shrinkage and incorrect distribution of internal stress. For plastics with low shrinkage, this is not critical. But if the shrinkage percentage is more than a few percent, the model may burst in layers.

For printing with such plastics, it is recommended to use a printer with a closed housing. If this is not possible, try to avoid drafts and sudden temperature changes in the room where the 3D printer prints as much as possible.

Print temperature

Due to too low printing temperatures, the layers may not “stick” well to each other. Raise the print temperature in the slicer settings.

Hardening (if the model cracks after printing)

Sometimes cracks appear on the model a few days after printing. This is due to uneven distribution of internal stress after cooling. You can try to “harden” the finished product.

For hardening, the model is placed, for example, in an oven, and heated to the softening temperature of the plastic. After that, the heating is turned off and the oven is left to cool slowly with the model inside. Due to this, the stress inside the print is distributed more evenly. But accuracy is very important in this method - if you make a little mistake with the temperature, the finished product can “float”.

Ringing

In places where the extruder changed direction, ripples are visible. Most often it looks like a shadow around the “sharp” protruding elements of the model.


Mechanical problems

Sometimes the problem occurs due to extruder play. Check if the extruder mount to the rails is loose. Be sure to check the tension of all belts.

High print speed or high accelerations

Moving the extruder too fast can cause vibrations that cause ripples on the wall of the model. The lighter the weight of the extruder, the less noticeable the ripples will be. To get rid of ringing, simply reduce the print speed in the slicer settings.

Slits for thin-walled models (not solid shell)

The thin wall of the model is not solid, but consists of two thin walls with a narrow gap between them. This problem is often faced by fans of printing "cutting" for baking.

Left model with wall defect, right without

Wall thickness and nozzle diameter mismatch

If the wall thickness is 1 mm, and the nozzle diameter is 0.4, it turns out that for a solid wall, 2 nozzle passes are few, and 3 are already many. The result will depend on the slicer algorithm, but most often you will get 2 walls with a thin slot in the middle (the slicer cannot change the wall thickness). The solution to the problem may be a slight refinement of the 3D model or the use of a different slicer.

Algorithms for calculating 3D models are constantly being improved and refined, and now this problem is less common.


When modeling, take into account not only the thickness of the nozzle, but also the percentage of “overlapping” of lines on each other. If you have a nozzle with a diameter of 0.4 - make the wall in your model not 0.8, but 0.7 - 0.75.

Wrong model geometry

When instead of a circle you get an oval, and instead of a square you get a semblance of a rhombus.


The main reason is malfunctions in the mechanics of the printer. Be sure to check:

Belts

Check belt tension in x and y. Belts stretch over time and may need to be tightened or replaced. Each 3D printer has its own way of tightening the belt. If the belts are slightly stretched, you can tighten them with the help of a "spring".

Loose pulleys, etc.

Check if all bolts and nuts are tight. Are there backlashes. Pay special attention to tightening the pulleys located on the motors along the x and y axes.


Sagging of some parts of the model

Some parts are not printed, broken, or instead of a neat surface, a swollen plastic snot is obtained.


No support for overhangs

A 3D printer cannot print in the air, so if there are overhanging elements in the model, you need to set supports - supports. The slicer can set the necessary support itself, you need to check the appropriate box in the settings.


When printing with soluble support, you can set the gap between the model and support - 0. This will make the surface smoother. If the support material and the model are the same, you need to add a small gap. Otherwise, it will be difficult to separate the support from the model.

Split model

Sometimes the supports can take more plastic than the model. In this case, to save material and time, it will be more convenient to cut the model. If you have more than one 3D printer, then the model will print several times faster.

When cutting the model, you can leave grooves or mortgages so that the pieces of the model are connected without displacement.


Totals

In this article, we talked about the most popular 3D printing defects and how to solve them. Don't be intimidated by such a long list. Some problems are rare and you are unlikely to encounter them.

There is a list of problems that arise due to the design features of a 3D printer, so try to choose a printer that suits your needs. To do this, you need to understand what products and what material you need.

Problems associated with printing algorithms are quickly eliminated by software developers.

Do not be afraid of possible difficulties and each print will be successful.


Troubleshooting 3D printing・Cults

This article should help you identify various 3D printing problems. Find the image or description in this list that best describes the problem you're experiencing. We offer some tips that should help you solve this problem.
As you know, 3D printing is an empirical process and it is through mistakes that you learn to understand, set up and use your machine. With the help of this list, you should be able to resolve the major bugs. If you are still experiencing issues or have additional tips to add to this list, feel free to contact us and let us know!

#1 Drooling

Symptom
Thin threads are woven into gaps between different parts of a 3D printed part.

Common Name: oozing

Possible Cause
Plastic continues to leak out of the head as it moves due to residual pressure in the heater and fluidity of the molten plastic.

Suggested remedies
Increase filament retraction length in Slic3r, retraction distance in CuraEngine. Retracting the filament will cause the pressure in the print head heater to drop. The effect can be modulated by adjusting the retraction speed directly in the slicer.
Increase print head speed. This allows the melted plastic to spread less time and leave marks between the printed parts.
Reduce the extrusion temperature of your plastic. If it is too high, the plastic becomes more fluid and flows out of the extruder faster.

#2 It is collapsing

Symptom
Collapse or poor quality of the overhanging surface, leaving small bumps.

Common name: overhang

Possible cause
The plastic deposited on the periphery of the protrusion does not solidify fast enough, so the deposited filament moves before it solidifies. The phenomenon is repeated or emphasized from one layer to another.

Suggested fixes
Vent the deposited plastic more efficiently, for example by adding a fan to the extruder or directly with a portable fan.
Create print supports under the overhangs.
Reorient the part to avoid overhangs.

#3 Flaky sides or top

Symptoms
Contours not bonded enough.
Flat surfaces are not completely covered.

Possible cause
Not enough material is deposited. Too narrow, the deposited wires do not touch each other enough and therefore do not stick to the adjacent wire.
There is dirt in the nozzle, which prevents the passage of the melt.
The extrusion temperature is too low, the wire dries out too quickly or shrinks and therefore does not stick to the adjacent wire.

Suggested Tools
Calibrating the extruder to obtain material flow according to data received from the slicer.
Unlock the extrusion nozzle.
Increase extrusion temperature.
Increase the blending speed in your slicer.

#4 Not enough material on thin parts

Symptom
The edges of a very thin area are not strong enough, not enough material.

Possible cause
Recycling or reworking is not effective enough.
Incorrect filament solidification.
Slippage of the thread drive during retraction.

Suggested remedies
Reduce the retraction speed and length while printing.
Increase "extra leg length when retracting" when using Slic3r.
Increase the spring pressure on the driven gear.

#5 Blisters

Symptom
Blisters, mismatched geometry, such as small bumps that are seen mostly in areas with a small surface area.

Possible cause
The filament is too hot during extrusion or the filament cooling system is not effective enough.

Suggested media
Place more parts on the plate while printing. In this case, the nozzle will print more objects and therefore allow more time for the part to cool before passing over it again.
Improve the cooling of your 3D printed object by adding cooling systems.

#6 Thin walls delaminate

Symptom
At a thin wall without filler, the threads diverge, they are not glued together on the sides.

Possible Cause
The walls of your 3D print are too thin or they don't fit so small.

Suggested tools
Draw thicker walls to adapt to the thread thickness.
In the slicer settings, set a sludge width that is a sub-multiple of the wall width while remaining consistent with the extrusion diameter and layer height.
Change slicer.

#7 Layer shifts horizontally

Symptom
The layer is shifting in the X or Y axis (or both).

Possible Cause
Print head or plate movement problem.

Suggested fix
Reduce the acceleration on the axis that has the problem.

#8 Layers shift evenly

Symptom
Layers almost always shift along the X and/or Y axis after a certain print height.

Possible Cause
Head or plate offset failure due to overheating of motors going into safe mode.

Suggested fix
Cool engines with cooling systems (fans).

#9 Corners curl up

Symptom
Deformation in Z direction during 3D printing. This figure increases in case of a strong overhang.

Common name: curling

Possible cause
Poor curing, shrinkage effect due to temperature difference of the wire deposited on the previous cooled layer.

Suggested Solutions
Increase slope in the 3D part to reduce overhang.
Further cooling of the deposited plastic using a ventilation system.
Add print supports to affected areas.

#10 Corners fall off

Symptom
The corners of the printed object are peeling off the plate, creating an uneven base.

Common name: warping

Possible cause
Poor fit between workpiece and insert.
Material shrinkage factor too high.
The first layer is not pressed enough against the board.

Suggested Solutions
Change media as PLA is less likely to warp.
Apply adhesive to the printing plate (glue, tape, varnish, etc.).
Correctly adjust the plate height before printing.
Apply a thinner first layer to further crush the deposited wire.
Add a bezel under the first layer.
Heat up the stove.
Clean and degrease the base.
Change the filling strategy. Fill the bottom concentrically instead of linearly, then fill the inside in a honeycomb pattern to avoid any shrinkage effect.
Reduce the internal fill density of your 3D printed object.

#11 Extrusion density too low

Symptom
Incorrect material density.

Possible cause
Material consumption too low

Suggested remedies
Unlock the extrusion nozzle.
Filament blocked upstream of extruder (e.g. spool assembly)
Check thread drive (e.g. knurled screw problem)

Corners #12 not forming correctly

Symptom
The corners are not straight enough, they can even stick out and increase the size of the part.

Possible Cause
Too much material is deposited in the corner because the nozzle slows too much as it passes through the corner.

Suggested remedies
Intentionally soften the corner of the part in the 3D modeling software.
Increase the "jerk" on your 3D printer's axis control.

#13 There are black drops

Symptom
Burnt (blackened) plastic in some areas of the printed object.

Possible Cause
Poor nozzle seal causing burnt PLA or ABS to drip around the nozzle.

Suggested fix
Remove the nozzle and close it again.

#14 Layers poorly welded

Symptom
Part breaks at attachment point between two printed layers.

Possible cause
Too much cooling, the deposited layer does not adhere well to the previous layer, because it was not hot enough during the deposition.

Suggested remedies
Reduce fan speed during printing.
Increase the minimum print speed in the slicer.

#15 Bubbles form on the first layer

Symptom
The first layer comes off the plate locally in the form of bubbles.

Possible Causes
Moisture present in the material which gradually evaporates upon contact with the heating plate.
Insufficient heating plate temperature for the material being used.

Suggested products
Store raw material rolls in a dry place, in closed packaging, with a desiccant bag.
Dry damaged material: place in a rotary oven at 40°C for approximately 3 hours. Be careful not to heat above 45°C or 50°C as this may cause the threads to stick together in the bobbin and even lose their cylindrical shape.
Increase the temperature of the heating plate.
Printing on tape or special adhesive.

#16 Fragile top and bottom

Symptom
Horizontal sides too thin and brittle.

Possible Causes
Insufficient material thickness above and below thin fill print. The laid threads have too few support points and break between the threading ribs.

Suggested products
Place at least 2 or 3 fully filled layers ("Solid layers" option in Slic3r) for the "top" and "bottom" faces.
Increase the fill of your object.

#17 Hole tops collapse

Symptom
Horizontal center hole top wires collapse during construction.

Possible causes
Plumb line too horizontal.
Mismatch between nozzle temperature, wire cooling and speed.

Suggested fixes
Reduce or eliminate this overhang area by modifying the 3D file geometry. An example is in the large hole in the photo, shaped like a drop of water, not a cylinder.
Add print supports below this area if the ledge is too difficult for the 3D printer.
Avoid too much slowdown in this area, even if the layer print time is short.

#18 Color or clarity varies

Symptom
The color or transparency of the material changes in different areas during 3D printing.

Possible causes
Different crystallization of the material due to different cooling rates. This may be due, for example, to the printing time of individual parts of the object or to the power of the fan.
Radiation from the nozzle can affect the thermal cycle of the previous layer and thereby change its appearance.
The applied layer is too hot because the underlying layer has not had time to cool.

Be careful, the physical-mechanical properties of the part may change due to these differences in crystallization!

Suggested fixes
Better control of cooling with slicer settings: change fan power based on plate cooling time or slow print speed in proportion to plate surface.
Reduce extrusion temperature for faster and more uniform phase transition.

#19 Layers are delaminating

Symptom
Some layers are flexing and cracks appear between the different printed layers.

Possible causes
Twisting phenomenon due to the effect mentioned in #9 the above happens between layers.
The wire cools too quickly at the exit of the nozzle, it does not weld properly with the previous layer.
Severe contraction of the material during cooling or phase change.
Some materials extruded at high temperature (ABS, PC...) may present a significant shrinkage phenomenon.

Suggested remedies
Change the extrusion temperature.
Change the media.
Avoid blowing on a deferred wire, reducing fan power, or placing the printer in a draughty room.
Close the assembly area in a controlled cabinet at a temperature close to the glass transition temperature of the material.

#20 Drops appear

Symptom
Drops of material are deposited at various points on the side surface of the 3D printed object.

Possible causes
Excessive extrusion when resuming extrusion after stopping extrusion when moving from one point of the part to another or when changing layers.

Suggested Remedies
Some slicers have a setting that allows, after a pause in printing, to request that more be pushed in before resuming normal printing than was removed by retraction.

#21 Bowden extruder salivation

Symptom
Extruder Bowden is either running too hard or not running enough. First impressions of your extruder are not great, too much extruded material, bridges between different areas in motion where extrusion should stop.

Possible cause
Insufficient thread shrinkage to compensate for gap in Bowden tube. Depending on the diameter of the tube and filament, as well as the length of the body, the motor must draw a certain length of filament through the bends of the tube before the filament is drawn out of the heating head.

Suggested fixes
Increase the "pull" distance in the slicer. The detail on the left was printed with 1.5 mm of indentation, which was clearly not enough. When the pull-in distance was increased to 6mm, the center part was printed. Too much shrinkage causes hot material to enter the thermal break, the temperature of the thermal break gradually rises, and the melting thread eventually gets stuck in the thermal break. The engine is no longer able to effectively push it. Reducing the retraction distance to 4 mm results in the part shown on the right.

#22 Streaks or regular patterns on extrusion

Symptom
Repeating patterns appear on the walls of 3D prints.
The pattern may change depending on the direction of movement of the motors.

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