3D printer threading: five simple solutions

3D Printer threading ：5 A simple solution

When FDM The printer Nozzle When you cross the open space to the next point , It may sometimes ooze molten plastic , Then it solidifies and adheres to the printing unit . This is a 3D Printer string , It makes you 3D The print unit has thin plastic threads similar to spider webs or hair .

In theory , Your nozzle should not deposit plastic when spreading in the open air （ Also called travel mobility ）. However , Molten plastic often leaks onto parts that should not be leaked , Make your print look like “ beard ”.

FDM The main reason for the string in the printer is to use the incorrect retraction setting and set the hot end temperature too high . for example ,PETG A relatively high melting temperature is required , also It is notorious for threading . However ,PLA and ABS There's a problem .

Fortunately, , There are some ways to prevent 3D Printers are strung . Let's see ！

3D Print troubleshooting common 3D Printing problems

Enable retraction

When retraction is enabled , The melt area rises （ source ： SublimeLayers)

Enabling retraction is for countering 3D The most common method of printer serial connection . Enabling retraction means , Where the extruder must pass through the blank area , The filaments will be pulled back by the feeder - Just a little bit . This prevents molten plastic from dragging behind as the printer head moves , because “ Pull back ” Action can be used as a countermeasure to prevent exudation . Once the extruder reaches the next position , The filament will be pushed back , Print is restored from the nozzle again .

In most slicing applications （ Such as Cura） in , Retraction is usually enabled by default . however , It's always a good idea to make sure it's true , Especially when you start to encounter strings . If the retract setting is turned on , And you still encounter 3D The printer is connected in series , You may need to enter the details of the retraction setting ：

Retract distance

The retraction distance is probably the most critical retraction setting , Because it determines the distance the filament travels . Usually , If your nozzle can be further retracted , It means that you are unlikely to encounter 3D Printer threading . But the same , If you retract too far , When you need to resume printing , The filament may not be available at the hot end .

The retraction distance may vary depending on the type of extruder you use . However ,Bowden Extruders on units usually require a longer retraction distance , Because the distance between the nozzle and the drive gear is longer .

To determine the correct retraction distance , You may need to perform a test print . Try this. Retract test print ： It prints fast , You don't need too many filaments .

Retraction speed

Retraction speed Determines the speed of filament retraction . Faster retraction speed indicates 3D It is unlikely that the printer will be wired , Because the filament is pulled back fast enough before it begins to seep . however , When the retraction speed is too fast , It may cause the filament to be disconnected from another part in the nozzle . What's worse is , The rapid movement of the drive gear may grind the molten plastic and clog the nozzle or create areas where the filament is not deposited .

therefore , You should focus on finding the best point （ Between slow and fast ）, Retraction is the best . This best point may vary depending on the printed material . Perform some test printing to determine the desired retraction speed .

If you are still unsure what to do , Please check out Simplify3D. The program comes with a preconfigured configuration file , If you are looking for the best retraction speed , This is a good starting point .

What settings should be used ？

Different retraction settings can significantly increase or decrease spots （ source ：Domoticx)

To determine the optimal retraction value , You must first know the extruder you will use and the material you will print .

ABS and PLA The speed of such materials on the direct drive extruder is 40 to 60 mm /s, The retraction distance is 0.5 to 1.0 mm. On the other hand ,Bowden The extruder on the unit usually needs 30 to 50 mm / s The speed of , The retraction distance is about 2.0 mm. These numbers are not constant , Can vary according to many variables .

At the end of the day , When the retraction is done correctly , It can effectively end threading , And it will give you more control over the printed matter . Some slicer programs （ Such as Simplify3D） Incidental “ coast ” and “ erase ” Parameters , These parameters are a powerful tool for further dialing in retracted values .

Set the appropriate temperature

This beautiful model will help you find the perfect temperature （ source ：dede67 via Thingiverse)

As the temperature goes up , Even after adjusting the retract setting , Printing materials will also become more liquefied , And more likely to drip from the nozzle . The lower temperature reduces this possibility . however , You must be careful not to set the temperature too low . Very low temperatures will not melt the filament enough , This may cause extrusion problems .

The ideal temperature depends on the printing material and other printing settings . however , Once you notice the string , It is generally recommended to reduce the temperature . You can try to lower the nozzle temperature 5 To 10 °C, However, do not lower the temperature below the manufacturer's minimum specification . Here are some common recommended temperatures for some of the most common filaments ：

• PLA ： 180-220 °C
• **ABS：**200-250°C（90-100°C Printing bed ）
• PET： 215-235 °C
• ** Thermoplastic elastomer ：**210-240°C（20-70°C Printing bed ）
• **PVA：**160-190 °C（60 °C Printing bed ）
• **TPU：**230-250°C（60°C Printing bed ）

Use Temperature calibration tower Test printing is a good way to determine the ideal temperature of each printing material .

For further guidance , We The article about the best printing temperature of different filaments Covers the most common filaments , If you are looking for the ideal printing temperature for your filament , This is a good starting point .

Adjust the printing speed

stay Cura The driving speed can be easily adjusted in the （ source ：All3DP）

Printing speed also affects 3D Printer stream . for example , If your nozzle moves between two points for too long , Threading may occur , Because molten plastic has more time to seep from the nozzle . however , If the extruder can travel faster , That short movement may be fast enough , So that the filament does not have enough time to seep .

Increasing the travel speed of the nozzle without trying to print can reduce 3D Threading of printer , But if the temperature is low and the printing speed is too high , May eventually be squeezed , Because the plastic will not have enough time to drip .

Usually , For most print materials ,190 to 200 mm / s The speed of can work normally , but MatterHackers Find out 150 mm / s Ideal driving speed for most printers .

Gourmet coaster PLA Waiting for the best 3D Print speed setting

As the Creator , You need to verify the running speed of the printer first , Then you can decide to make any adjustments .

As the Creator , You need to verify the running speed of the printer first , Then you can decide to make any adjustments . for example ,X/Y The axis travel speed represents the travel speed from one side to the other , This speed is directly related to the length of time it takes for the nozzle to move in the blank space .

image Simplify3D Such a program has a function , It can ensure that the travel path is short enough to reduce leakage , Even if it means avoiding open space completely . in fact , Most slicer packages have a setup , You can speed up the nozzle for nonprinting motion .

Clean the nozzle thoroughly before printing

You can use a brush to clean 3D Printer nozzle （ source ：Airwolf 3D)

When you use the printer for a long time , Especially for images PETG Such a single type of printing material , The filament will leave a thin layer of residue in the nozzle . This thin layer may cause 3D Printer threading , Because the filaments will try to adhere to the surface of the printing unit .

To avoid such problems , Make sure that the nozzle is thoroughly cleaned before any printing , To remove any dirt from the previous filament . For more guidance , Please check us out Detailed nozzle cleaning instructions .

Keep your filament free of moisture

Airtight drying oven can protect your filament from moisture （ source ： mcfada via Instructables)

PLA Is the main culprit here , Because with ABS comparison , It tends to absorb more water . Once moisture is present , As the plastic heats , It often turns into steam . This steam can be mixed with plastic , And can increase the possibility of exudation during non printing campaigns .

therefore , You should Store the filament in a moisture-free environment , For example, plastic box , Especially if you live in a humid environment .