With the popularization and application of 3D printing technology, 3D printing has gradually in our daily life has quietly appeared, for 3D novice, in the process of 3D printing, if there are some common problems, such as pulling or stringing, which affects the quality of the finished model of the 3D printing more.3D printer printing process is prone to stringing or pulling, the cause of which is usually associated with the improper control of the material extrusion, UJOYBIO3D on the slicing temperature settings have been in: 3D Printer Slicing Temperature Setting Guide, The Impact of Slicing Temperature on Finished Models, This article has made a detailed analysis, the following on some common printer wire drawing or stringing problems, respectively, to do analysis and solutions.
1. printer nozzle temperature is too high
Reason:
When the 3D printer nozzle temperature exceeds the optimal melting temperature of the filament, the high temperature of the nozzle will make the filament material is too fluid, easy to move in the nozzle to continue to extrude or drip, the formation of fine filaments, resulting in the phenomenon of pulling or stringing. The main manifestation of the print nozzle in the gap between the path, the emergence of filaments or “cobweb” structure.
Solution:
We can be based on the current printer caused by pulling or stringing when the problem, and gradually reduce the printing temperature, to find the current filament material, the best printing temperature range, general filament material will be labeled on the package. If we do not find the current filament printing temperature labeling, we can reduce the temperature according to the current printing temperature by 10 ° C to test the method of reducing the temperature can be used to slice the software to provide dynamic temperature control features, such as reducing the temperature of the nozzle when the non-printing movement, but also can be set up directly on the printer.
Note: Usually to find the optimum print temperature for the current printing filament, you can print a temperature test tower to find the optimum print temperature for the current filament. The following table shows the optimum print temperature for various types of filament for reference.
| Material | Optimum print temperature (°C) | Hot Bed Temperature (°C) |
| PLA | 190-220 | 50-60 |
| ABS | 220-250 | 90-110 |
| PETG | 220-250 | 70-90 |
| TPU | 200-240 | 40-60 |
| Nylon | 240-270 | 70-90 |
| PC | 260-310 | 90-110 |
2. Improper nozzle retraction setting
Reason:
Insufficient nozzle retraction height, filament material is not fully pulled back inside the nozzle, resulting in continued extrusion during movement.
Nozzle retraction is too slow, resulting in the filament material not being able to retract quickly enough, leading to dripping of the molten material.
Nozzle retraction frequency is too high, resulting in excessive nozzle retraction frequency causing extruder wear or clogging problems.
Solution:
According to the parameters of the current print model, the retraction height and speed can be optimized appropriately, different printers and software default parameters are not consistent, can be adjusted according to the printer type. If the setting of the minimum retraction moving distance and the minimum retraction, avoid unnecessary retraction action to barely cause unnecessary retraction when it leads to the emergence of the phenomenon of pulling or stringing.
3. nozzle movement path planning is not reasonable
Reason:
If the printer nozzle passes through the blank area in a non-printing state, the filament material may drip due to gravity or internal pressure, forming a spider web of pulling or stringing lines in the model.
Solution:
This needs to be set in the printing software and enabled in the slicing software Avoid Crossing Perimeters. Optimize the movement path to minimize the distance of the blanking movement, you can also add a wiping tower, in the nozzle waiting period on the wiping tower to wipe off the excess filament, in order to dispose of the easy to cause pulling or stringing of the filament.
4. Moisture problem of filament material
Cause:
Long-term exposure of filament materials to humid environments can trigger the hygroscopicity of filament materials, such as PLA, PETG, nylon and other filaments is that some water will be absorbed, which will result in uncontrolled extrusion and stringing due to the evaporation of internal water to produce bubbles during the printing process. The surface of the finished model prints is rough, accompanied by obvious filament or bubbling sound.
Solution:
You can use a drying oven or dryer to dry the filament before printing, or you can use a microwave oven for a short period of time to avoid heating for too long, resulting in deformation of the filament and affecting the printing effect. Long-term storage, you can use a drying box, and use a certain number of vacuum bags and desiccant for processing.
5. Residual pressure in the printer nozzle
Cause
During printer operation, when the pressure of the melted filament material inside the nozzle is not released in time, the material may continue to flow out of the nozzle during movement, and this is also a common cause of drawing or stringing.
Solution:
At this point it is only necessary to adjust the retraction pressure setting on the printing software to relieve the pressure inside the nozzle. Enable the Coasting function in the slicing software to stop extrusion for a short period of time before the nozzle retracts to allow the nozzle to better handle the melted filament in the nozzle before retracting, thus avoiding pulling or stringing.
6. Insufficient nozzle cooling
Cause:
At the end of a print job in the printer, if the filament material in the nozzle chase is not cooled fast enough, it remains in the nozzle during the movement of the state of flow, is also caused by stringing phenomenon.
Solution:
Open the front door of the printer to accelerate cooling inside the printer
At this time you can increase the speed of the cooling fan in the cooling system to promote uniform cooling of the nozzle. If the printer is closed, you can open the door in front of the printer to accelerate the nozzle and model cooling to reduce pulling, but also allows the model to have a better molding effect.
7. Check the nozzle status and diameter
Cause:
If the printer nozzle is clogged or worn out, it can result in an erratic flow of material. A nozzle that is too large in diameter, or larger, can cause more molten material to flow out, increasing the likelihood of stringing.
Solution:
Printing nozzles need to be cleaned and replaced on a regular basis so that the model can be molded to be able to better avoid problems such as pulling and stringing. Can also be printed according to the type of filament, select the appropriate nozzle diameter, such as 0.4mm diameter nozzle is more commonly used.
8. Nozzle extruder problems
Cause:
Printer nozzle in the extruder is not calibrated or pressure is not enough, it will lead to the filament material melting supply is not uniform, this will result in more serious filament pulling.
Solution:
At this point, you can calibrate the extruder step values (E-steps) to ensure that the extrusion volume matches the filament material. It is also necessary to check whether the extruder gears are worn or slippery, if they are already worn or slippery, they need to be replaced in time.
9. Printer Environmental Problems
Cause:
Here refers to the printer environment, mainly refers to the printer is located in the working environment of the temperature and humidity in the two aspects of the problem, when the 3D printer is in an environment with too high a temperature or humidity is too large, may be exacerbated by the filament material in the high-temperature environment is not cooled in a timely manner, in the case of high humidity, the cooling effect is not good, affecting the extrusion effect of the nozzle, and ultimately lead to the entire printing process produces pulling or stringing problems.
Solution:
If the environmental problem is too high, and when it is a closed printer, it is necessary to open the front door of the 3D printer, so that the inside of the printer to deal with a good ventilation environment, in order to allow the printer nozzle to have a better cooling effect.
In a humid environment, you can also use the same method to improve the humidity inside the humidity printer, and printing filament humidity problems, you need to dry the filament before printing, you can use the drying box and other methods to allow the melted filament has the best molding effect, to avoid the nozzle due to environmental issues such as pulling or stringing.
10. Characteristics of the filament material
Reason:
Due to the fluidity and hygroscopicity of different filament materials have large differences, and you use the same method of printing, then the final printing effect is certainly very different, some materials like PETG filament material itself is more prone to pulling, so it is necessary to deal with the characteristics of the filament material itself.
Solution:
UJOYBIO3D's filament uses desiccant to dry the filament
For different types of materials, it is necessary to choose the appropriate slicing parameters, especially the temperature, retraction, fan and other settings. In order to avoid drawing or stringing problems as much as possible, in order to find the right 3D printing filament material for you.
UJOYBIO3D will give you an example of the characteristics of various filament materials that can easily cause filament pulling or stringing through the following table for your reference:
| Material Type | Stringing characteristics | Caution |
| PLA | Low melting point, high fluidity, tends to produce slight stringing at high temperatures. | Control print temperature (190-220°C). Use high efficiency fan cooling (80%-100%). Use moderate retraction settings (1-3mm, 30-50mm/s). |
| PETG | High flowability, easy to produce fine draws and drips. | Easier stringing than PLA. Lower print temperature (230-250°C). Increase retraction distance and speed (4-6mm, 30-50mm/s). Enable Coasting function of slicing software. |
| ABS | High viscosity in molten state, medium risk of stringing. More prone to dripping when cooling is insufficient. | Control the print temperature (230-250°C). Reduce cooling fan speed to ensure interlayer adhesion. Use enclosed printers to reduce ambient temperature fluctuations. |
| TPU | High elasticity results in a material that does not retract easily and stringing is evident. High fluidity results in frequent dripping. | Reduced print speed (20-40mm/s). Increase retraction speed (30-40mm/s) and reduce retraction distance (1-2mm). Control temperature (200-220°C). |
| Nylon | Highly hygroscopic, moisture can cause severe stringing and bubbling. | Ensure the material is dry, use a drying oven or dryer. Control print temperature at (240-260°C). Increase the ambient temperature by using a closed printer. |
| PC | Printing at high temperatures is sticky and prone to filaments. | Control print temperature (260-300°C). Use high quality cooling fan to control dripping. Increase retraction settings (3-5mm, 30-50mm/s). |
Summarize
Solving 3D printer stringing problems requires a combination of adjustments to nozzle temperature, retraction, path planning and cooling settings, and also regular maintenance of the 3D printer. Then gradually test the parameters, proportionally using methods such as temperature towers and retraction tests.
As well as familiarizing yourself with the characteristics of the 3D filament material you are using so that you can figure out the settings that best suit your printer and material is key.
The PLA+ filament material produced by UJOYBIO3D is a supplier model that integrates R&D and production, and the recommended optimal printing temperature is 220°C, which is labeled in the conspicuous place of the filament spool, so that users can better grasp the printing temperature of the filament printing. We also provide 24-hour online after-sales service to bring users a more friendly printing experience.
