Help with 3D printing and nozzle before print

[lifeguard]

Hi.
I'm really happy with my printer.....but there's one big problem: filament keeps going out on nozzle BEFORE print start. While extruder are heating, the filament start to melt and going out on nozzle, but just by 'gravity', not because extruder are working or pushing filament. This causes a mess when printer start to print, since ther's a gap to fill on nozzle and there is a lot of plastic on nozzle too, making first layer a messa. Everytimg I need to use a tweezer to clean nozzle just when they start to move.
My question is: there is way to solve this or, at least, automatize this cleaning proccess?
Sometime ago I remember something on default script of simplify3d that when printer start printing, they put nozzle in one spot of heatedbed and about 1mm above bed, then just push filament for sometime.....this makes a 'ball' that stick to bed and when nozzle goes up, they are clear! But I don'nt have this script anymore and I really don't know if it really works.
Anybody with 3d printer has any idea or tip for this problem?

[Vineyards]

3D printers use a version of g-code. In other words, there is a single command for most everything that 3D printer can do.

G1 X0 Y0 Z0 F4800 ; go to the zero point

G1 X195 Y20 F4800 ; go to the starting waste point

G91 ; set relative

G1 X180 Y80 E15 F600 ; go to the end waste point extruding 15mm of plastic all the way

G90  ; set to absolute

There are tons of information on the Internet. F.Y.I.
G1= Fast move X0 = Move X axis to 0. You know Y and Z. E1 command is for extruder. Units are in millimeters. F= Feed rate. Other commands are already explained. There must be a complete auto clean routine somewhere but if you think you can clean your 3D printer by using a certain sequence you can replicate that using these easy g-code commands.

Posted on: February 04, 2017, 07:25:35 19:25 - Automerged
Note: this assumes your hot bed and nozzle are hot already if not there are commands for heating them too. For example:

To heat hot bed to a 70 degrees: M140 S70
To heat extruder nozzle to 180 degrees: M104 S180.
Just put them to their proper places in the sequence.

[pickit2]

Sailfish does that puts a spot down first then moves to start position.
I don't have a problem, but if it happened to have an air gap it would sort it when head reaches start.

[Parmin]

Nozzle too hot may cause the filament liquidus too thin. 
Lowering the nozzle temperature will increase the viscosity of the filament and thus less chance of it to drip.

[solutions]

Usually you print a brim first with your slicer to ensure when you hit the model, she's ready to go.

It's not gravity - your extruder is pressurizing the nozzle. You do realize you can retract the filament to stop the extrusion?

[lifeguard]

Hi!
I know I can retract and the problem is not with nozzle temperature. I managed to almost solve this issue, but in all code I must end with retract, so the next print there`s no pressure on nozzle....but this MUST be done in the end of all prints. If I do this at begining, it's late.

[solutions]

Print the brim, then the model

[Mworks]

I have a folgertech 2020 model and this is the code I use in all my prints at the start:
G28 ; home all axes
G29; auto bed level
G0 X0 Y0 Z0.15 F9000        ; Move to the home part of the bed.
G92 E0                      ; Zero the extruder.
G1 X40 E25 F500             ; Extrude a fat line of filament to prime and clean the nozzle.
G92 E0                      ; Zero the extruder.
G1 E-1 F500                 ; Retract 1 mm.
G1 X80 F9000                ; Sweep right to cut any strings.
; Begin printing.