Stringing or Oozing

Detailed Guide on Stringing or Oozing causes and Prevention.

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Stringing occurs when the extruder pulls away from a point in the model and travels to another without reliving all the pressure in the system. The general way to fix this is retraction but there are other options the following is a list of ways to prevent stringing.

• Print Colder Temperature - Often times stringing occurs due to the melt from the hot end leaking out even when the pressure has been removed this effect can be countered when the hot end is simply lowered to avoid the excessive heat travel causing more melted filament in the hot end then is needed.

• E-Step Calibration - Ensuring the correct value of filament is actually extruded if the filament is over extruding it can create more pressure then the system is being told resulting most often in blobs more then strings or Oozing.

• Speeding up or slowing down retraction rate - By increasing or decreasing the retraction speed you can quicken the speed that the material is pulled back however if the material is pulled too fast it will not be able to resume correctly resulting in a indent on the layer due to the filament not being fully extruded. Too slow and it may cause more stringing.

• Better cooling fans - Sometimes it’s necessary to upgrade your cooling fans to better solidify the material coming out of the nozzle, ideally in most printing you want the material to nearly instantly become solid after exiting the nozzle at the moment it touches the previous layer, the nozzle itself should be doing the bonding but as soon as the extruder is off the filament for stability you want it to cool, this is similar to Printing Colder.

• Increase Travel Speed - If your nozzle isn’t moving fast enough when not printing it can can allow for the hot end to leak even with good retraction settings so increasing the rate of travel will allow the print head to move quicker between open areas. Travel speed can be well over the actual printing speed but this will differ from each unit. Your Printers maximum speed should be what you aim for when setting your travel speed, a simple google search “Exact Model name” “Max Travel Speed” will generally give you a quick answer.

• Clean your nozzle - While it may sound intuitive, checking your nozzle regularly for leaks or stuck on filament is something you should do often. Heat your machine up then turn off the power or unplug it. After using a brass brush clean the nozzle off gently, avoid touching the wiring if there is any overflow use a small pair of needle noose plyers to remove any plastic gum, if you have your printer around 125 the plastic will be about the consistency of chewing gum and be easy to remove.

• Keep your Filament dry - Most filament will have tiny pockets of water trapped inside this will explode and vaporize during your prints sometimes heard as a popping sound, but even mildly damp filament can do this, ideally your filament should be around 15-20% moisture level. A dry box is a good way to keep your filament safe. PLA is hydroscopic meaning it will absorb moisture in the air so if it was packed or manufactured someplace else it may be wet just fresh out of the package. You can also use a food dehydrator to remove moisture, have a scale ready note the weight of your filament put it in the dehydrator for a day weigh it again and continue until you see no noticeable loss of weight. This will let you find out how much moisture you removed from your filament.

• Quality Filament - If you’ve tried all these things try changing to another roll preferably a different color or brand.