Uneven Print Quality

[tuc36436 0]

Hello Everyone,

I wanted to ask a quick question. I am trying to print something and I am getting uneven material extrusion after a couple hours of printing. I am using PLA to print and after 3 hours of print, the material is coming out uneven. This has caused a couple print failures and lately I can't get a finished print out of the machine. One of two issues is occurring:

1. The nozzle moves and no material is coming out mid print.

2. 2 Parts are being printed simultaneously, one part is coming out fine while the other shows uneven[/media-thumb] material extrusion (Take a look at the attached pictures).

Info:

1. Print time 12 hours

2. PLA

3. Standard setting in Cura for print temps (not sure how to change those)

3. Ultimaker native material (silver color)

4. All standard settings in Cura except for print speed (30 mm/s)

Please Help!

Thank you everyone!

AS.

[gr5 2,271]

You have severe underextrusion or maybe zero extrusion.

I guess the first thing to check is the "third fan". Is that coming on as the nozzle heats above 50C? Having that fan fail is a common cause of this kind of thing.

There's lots of possibilities - could there maybe be too many retractions? If the same piece of material goes through the feeder 20X it's usually fine but 40X or 100X and it can grind the filament down to dust by the 40th time going back and forth over the same spot. This infill looks fine but maybe another area?

Your nozzle could be much colder (pla like toothpaste) or hotter (pla chemically changing) than you thought.

Your feeder stepper combined with warm air nearby can cause the extruder to get above the glass temp of PLA and the PLA melts/squishes.

The PLA may be brittle and breaking in the bowden and catching in the print head - this has been very very common this last few months.

You need to start eliminating some of these possibilities.