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I cannot get prints to start correctly - Prusa I3


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Posted · I cannot get prints to start correctly - Prusa I3

Hi, I have a Prusa I3 Mk1 and cannot for the life of me get the start of my prints good. What I've resorted to doing is having a skirt or brim so that when it gets to the actual print part the filament is ok. However, I now want to print the frames for the CoViD-19 masks, and they barely fit on my bed, meaning I can't use a skirt to start the job.

 

So the first thing that I notice, is that when I load the filament, once finished it the nozzle continues to have filament come out for a minute or so. This may be the main root of my problem? I'm printing PLA at 200 deg C.

The next thing I notice is there is I guess a wiping procedure, where the nozzle is dabbed on the bed and raised. I guess the dab is to get filament to stick to the bed, then it raises up to get rid of the excess? After the lift, it used to move to the start point, lowering as it went. But since Cura 4.4, it now lowers again and skims the bed to the start point. To me, the approach from 4.4 onward is bad, as any oozing filament stick to the bed. Potentially where you are going to print something. I don't believe there is anything in the printer G-code to tell it to lower again. I've put it below. Also, when I used Prusa Slicr, it used to travel along the bed a little to clean the nozzle. Could this be done in cura?

The issue I have is that sometimes I end up with rogue filament on the bed. Sometimes it clumps on the nozzle. Either way, it messes up the print. Any help would be massively appreciated.

Printer: Original Prusa I3 Mk1 (200mm x 200mm glass bed)
Cura: 4.5.0

Printer start G-Code:

M117 Let's get it started!
G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
M107 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
G1 Z15.0 F9000 ;move the platform down 15mm
G92 E0 ;zero the extruded length
G1 F200 E3 ;extrude 3mm of feed stock
G92 E0 ;zero the extruded length again
G1 F9000
M117 Printing...


I've attached an image with the settings.

 

1182628870_CuraSettings.thumb.png.94593c23bfaf838ba4ab3c89202d63f5.png

 

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