Sometimes while printing the printhead may leave thin strands of plastic while performing non extruding movements
When the printhead stops extruding in order to do a "travel" move from one geometry to another, (may it be within the same part or separate part) it leaves a thin strand of plastic dragging behind the printhead thus creating a cobweb like structure between the parts.
To be able to extrude and print plastic the extruder needs to heat the plastic until it melts and then push it thru the nozzle and on to the printing surface or previous layer. During this process a pressure is built up due to thermal expansion in the hotend to allow for continous extrusion of plastic.
If the printhead performs a travel move (meaning a movement that doesn´t involve any extrusion) the plastic will “ooze” because of the pressure already built up in the hotend.
The amount of oozing can depend on several reasons such as extruder temperature, material, speed or settings in your slicer etc.
Many of the bellow settings is not available in Flashprint, you need Simplify3D to access these settings.
To deal with oozing most slicers have settings for something called “retraction”. When activated this means that everytime the printer performs a travel move it will simply reverse the filament consequently stopping the extrusion to prevent the plastic from oozing. Many slicers have several settings you can tweak. The most significant setting is retraction distance which specifies the distance the extruder will reverse the filament. There´s also often an option to alter the speed at which the extruder is performing retraction. Increasing this value can help with issues caused by oozing.
The extrusion temperature can also be a key factor. If suffering from oozing lowering the temperature can help because of the plastic then becoming less fluent.
Increasing the speed at which the machine performs the travel move can also be a benificial factor.
Also layerheight and distance between nozzle, buildplate can play a role. For instance if the printhead prints to close to the print surface the extruder will not be able to push the amount of plastic thru the nozzle as intended thus creating backpressure in the heatchamber. when moving away from the printed geometry the built up pressure will push exess plastic thru the nozzle.
There´s also the fact that different materials have different characteristics and also might be more prone to ooze than others.
Filament can be hygroscopic, some more that others. This means it can absord moisture from the air which can cause stringing/oozing, poor print quality and/or failed prints. The filament can be dried to solve this, check manufacturers website.