PLA Stringing/blobbing

[ianeagland 0]

Hi

I am into my 3rd month of using an Ultimaker with ulticontroller for part production using PLA. I use Cura to great effect and on what I would describe as basic solid parts where the extruder remains with in the body of the object the results are excellent. However recently I have made a number of parts with projecting features (think of a table upside down on the bed with legs in the air). The issue is a lot of stringing and blobs where the extruder stops to move in air across to the next feature. Any suggestions as to the best strategy/settings to reduce this blobbing and stringing? The parts are perfectly usable and clean up with a knife but that is time consuming and I would like if possible to replicate the really clean finish I have achieved on other more basic parts.

[fuchs 0]

Berthos Extruder Modification and retraction (typically 2mm) ->

http://www.thingiverse.com/thing:26094

You can also lower the temperature a slight bit, try 2-4 degrees less.

[Daid 270]

Try entering 4.5mm of retraction distance, this really helps against stringing.

[ianeagland 0]

Many thanks.

I had retraction but clearly not enough. Nice clean print running as I type.

[Daid 270]

You might be happy to know that I set 4.5mm retraction as a default for the next release. And added a retraction on/off checkbox so you no longer need to set it back to 0 if you don't want retraction in a print.

[lobster2b 0]

Daid:

May i request another feature?

can you inclunde "layer: current/top" in the printing dialog? pretty please

[Daid 270]

Daid:

May i request another feature?

can you inclunde "layer: current/top" in the printing dialog? pretty please

How about a pretty accurate "printed for X time" and "X time remaining in print" values? And a "Printing at height Xmm" value?

[lobster2b 0]

oh. yes please.

i have noticed that print time in cura differes from actual print time

One said 3:36, 4:30 was correct

Another one was 0:49, 1:20 was correct.

it might be my setting but, ive highjacked this tread enough: look for another thread

[Daid 270]

No, it's a known problem. I actually had a talk with Erik about it today. And the problem is in the acceleration, the printing estimate doesn't account for acceleration. This can be solved, with quite some work, but it's not on the top of our priority list. (The Mac installer is)

[banana97 0]

If I set the retraction to 4.5mm - should I also set the Extra length to 4.5mm to re-prime the nozzle?

[SandervG 952]

It is also a good idea to print with the lowest temperature possible for the filament you are printing with.

This might take some tweaking to find the exact temperature because it may vary with different colours.

Also slightly increasing speed might save you some stringing.

[Daid 270]

If I set the retraction to 4.5mm - should I also set the Extra length to 4.5mm to re-prime the nozzle?

Nope, the "extra lenght" is extra, on top of the normal reversal.