I am using the E3D v6 hotend with the titan extruder. Everytime I go to do a test print, just enough stringy filament oozes comes out of the hotend "right before" it lays down the first layer. I have no idea why it oozes out the little bit of filament before it prints.... The unwanted filament builds up while some of the first layer is done. As a result, what has been printed or about to be printed get stuck together as it tries to do the rest of the print....
As the filament in the melt chamber heats up, it's going to inevitably ooze a little bit. Make sure you watch for this and clean it off as the hot-end heats up, and setup you slicing software to print a skirt, which will print a few loops around the outside of your print, separated by a few mm, to deal with ooze and get filament flowing properly.
If it oozes a lot, try reducing your print temperature a bit.
One possible solution is to "park" the hotend on the print bed as it is heating up. The bed blocks the nozzle, and prevents ooze from coming out. If any does come up, it tends to stick to the bed, not to the nozzle. You can do this by including an appropriate
G1 command in your start G-code.
In general, it's a bit normal to have some filament ooze during warm-up. However, if it seems to be an abnormal amount, you may want to consider reducing your target temperature.
Keep in mind that ideal extrusion temperatures are subjective to the source of your filament. Not all filament is of the same material quality and differing degrees of purity. Sometimes, the same filament will be of different quality from the same source. It might be worth dedicating the first bit of each spool to a bar test to determine what the appropriate extrusion temperature should be.
A simple test would be to use the control panel on your machine or use your software (whichever is easiest for you):
- Manually set the extruder to extrude filament
- Stop the extruder
- Clean excess material from nozzle
- Watch for ooze
- Gradually reduce the temperature
- Repeat until the amount of ooze is an appropriate to your liking
Also remember that there will be some left-over material from a previous spool when swapping spools.