Puddle when printing complex objects

[joe 0]

I have been working through calibration on a new machine. I have printed a few basic structures and fixed a few problems with belt tightness and z-axis height. I am trying to print a fancier fan duct and noticed a bit of puddling or excess pla as it starts infilling.

Here is a quick video of the first layers:

http://s1220.photobucket.com/albums/dd447/netrouter/?action=view&current=9a437dfb.mp4

I am using CURA with temp at 205, fill density 30% and layer height 0.2. Any guidance would be appreciated.

Joe

[goodwell 0]

Hi Joe,

I dont know where, but some one has Ask the same to daid in the forum.

I have the same phenom at the beginnig of printing. It is gone better at the second layer.

if i could Remeber, it is an surplus of matrial witch press by side while the nozzle ist near on ground for better liability.

(sorry for my english)

[spooner777 0]

From your video it looks to me as if your nozzle is to close to the bed. Try to lower the bed by a few 10th of a millimeter. If the nozle scraps over already layed up material, some will get picked up and you get small bumps.

If your first layer does not stick, try printing the first layer at 10% speed. That works for me.

Another thing I found out is that it is usefull to feed through some material by hand before EVERY print. Because at the end of the print and while heating up, some material flows out creating a lack in supply at the beginning of the next print.

I am printing for 2 months now so I am not an expert.

[joe 0]

Thanks guys. I will give these suggestions a try.

[chopmeister 0]

If you're using 0.2 layers, then I think your head is definitely too close to the bed. Also this could be a combination of that, and over-extruding. To be absolutely sure, recalibrate the extruder in Cura, extrude by hand before prints, and start printing immediately after doing the hand extrusion (remove excess plastic before printing, of course). Also raise the platform a bit. If you are using opaque filament, then at 0.2 layer thickness, you shouldn't really have any semi-transparent lines like you have on the video. At least in my experience.

[Daid 306]

That's clearly a "nozzle too low" case. This means it is extruding an excessive amount of plastic, which gets pushed out and upwards. You should also see that your first layer is a bit larger then the rest.

By default Cura prints the first layer with a height of 0.3mm, so the nozzle should be quite high above the bed. The 0.3mm layer makes it easier to have a wrong Z start height, an uneven bed, and makes it easier to remove the object. If you would have had a 0.1mm first layer then you would have most likely scratched the tape.

The mistake you made might be quite common. Most likely you calibrated the Z height with a cold nozzle. And the nozzle gets a tiny bit longer when you heat it up. So it should be slightly above the bed at Z0 when cold.