1mm nozzle advice

[paulrhee2002 2]

My prints require speed vs detail so I changed my nozzle to 1mm.  Will consider 1.2mm if I can get this straightened out.

My prints are coming out horrific.  I have attached pics below.

my settings were:

1mm width

.8mm height

3 wall lines

2 layers top/bottom

215 nozzle temp 

60 bed temp

25mm/s print and infill speed

Any advice is greatly appreciated!!!

[geert_2 557]

Two top layers is not enough to fill the roof smoothly. You probably need 4.

 

Further, on such a small object, I think it is not getting enough cooling: these thick sausages don't cool down and stay molten for too long, so they get dragged along and get deformed. Plus there is the hot nozzle sitting on top of this, radiating heat and preventing solidifying.

 

You will need to print multiple models at the same time, and bigger models. For a 1mm or 1.2mm nozzle, it will be hard to print details finer than ca. 1.5mm.

 

This is a guess, but it won't be far off, I think.   :-)

 

[AirBronto 8]

What printer/hot end do you have?  25mm/sec at 1mm width and 0.8mm height seems really fast to me.  You're extruding a ton of material at that speed.  Unless you have a really powerful hot end I could see the sheer volume of material dropping the nozzle temperature.  When the nozzle changes velocity, the extruded material isn't hot enough and gets pulled/separated from the lower level which gives you your rounded corners.

 

I would set your print speed to something really low, like 5-10mm/sec and try again.  If it looks better, your hotend probably just doesn't have enough thermal inertia to withstand the huge volume of material.  At that point you can either print slower or print hotter.

[yellowshark 153]

Never heard of anyone using a layer height a thick as 0.8, I cannot help thinking that this is one element that is probably causing a problem, but that is a guess, I have never gone anywhere near 0.8

 

Agree with @geert_2 on the cooling side. As a guideline I use 10 secs as my minimum layer time, with 100% fan,  again I am guessing but with 0.8 layers you may need more than 10 secs. Also I would experiment with the extruder temp. Try 210 and 220 and gradually find the best temp; e.g. if 210 is better than 215 then try 205. With a layer height of 0.8 I am sure any temp. suggestions from us will be guesses.

[geert_2 557]

I have done line-heigths of 0.4mm with a 0.4mm nozzle (=the only nozzle-size on my UM2), just for experimenting, and I started to see a bit similar deformations. Corners got rounded more than at lower heights, and it didn't cool well and deformed.

 

From left to right: layer-height = 0.4mm, 0.3mm, 0.2mm, 0.1mm, 0.06mm. Top row = 50mm/s, bottom row = 10mm/s if I remember well. Each block is 20mm x 10mm x 10mm.

 

This one is printed at 0.4mm layer height, 0.4mm nozzle:

 

The next one is 0.06mm. (Also, you see it starts to discolor due to sitting too long in the nozzle at elevated temperatures, even though I printed it below the recommended temp range. Material is PET.)

 

 

[paulrhee2002 2]

On 6/19/2019 at 10:19 AM, geert_2 said:

Two top layers is not enough to fill the roof smoothly. You probably need 4.

 

Further, on such a small object, I think it is not getting enough cooling: these thick sausages don't cool down and stay molten for too long, so they get dragged along and get deformed. Plus there is the hot nozzle sitting on top of this, radiating heat and preventing solidifying.

 

You will need to print multiple models at the same time, and bigger models. For a 1mm or 1.2mm nozzle, it will be hard to print details finer than ca. 1.5mm.

 

This is a guess, but it won't be far off, I think.   🙂

 

Lol “thick sausages”.  Makes sense but sometimes i am unsure if its not cooling enough or cooling too fast.  Will experiment with a fan for cooling.  Thank you for the advice and the chuckles

[paulrhee2002 2]

On 6/19/2019 at 10:19 AM, geert_2 said:

Two top layers is not enough to fill the roof smoothly. You probably need 4.

 

Further, on such a small object, I think it is not getting enough cooling: these thick sausages don't cool down and stay molten for too long, so they get dragged along and get deformed. Plus there is the hot nozzle sitting on top of this, radiating heat and preventing solidifying.

 

You will need to print multiple models at the same time, and bigger models. For a 1mm or 1.2mm nozzle, it will be hard to print details finer than ca. 1.5mm.

 

This is a guess, but it won't be far off, I think.   🙂

 

Lol “thick sausages”.  Makes sense but sometimes i am unsure if its not cooling enough or cooling too fast.  Will experiment with a fan for cooling.  Thank you for the advice and the chuckles.

will also try slowing down speeds and lowering the layer height as suggested.  

Thanks so much guys and i will update you on progress!!!

 

so nobody thinks this is an under extrusion issue?   My spool wheel is not smooth

[geert_2 557]

While there could still be underextrusion (hard to see), that alone would not cause the rounded corners, I think.

 

Too much cooling would rather cause no layer bonding, and thus splitting layers. But the shape would more accurately follow the nozzle-path.

 

Yes, putting a desktop fan in front of the printer at its lowest speed, and maybe 1m away, is worth trying. That would give a nice gentle flow.

[paulrhee2002 2]

Again, i cannot thank you guys/gals enough.  Will try everything you suggested

[paulrhee2002 2]

Slowed the print down from 25mm/s to 15mm/s and turned the coil fan speed up to 100%.  (it was at 50% but always seems to go at 100% no matter what I adjust it to)

 

kept all other settings the same as last print and here are the results.  Much better.

I have 2 prominent gaps on the walls and top is better but would hardly consider it neat.

 

So if you guys are up for some more questions:

1- are those gaps caused by under-extrusion and if so, why just at those 2 spots and the gaps go halfway around the cube.

2- would turning on combing significantly help the top layer cosmetically?  (I will just try turning it on and find out for myself)

3- do you notice any other issues I have not mentioned?  heat too high/low?

 

So I guess I'm just wondering about those gaps and if there is anything else I can do to clean up the print.

 

This was printed at:

15mm/s

.8mm height

1mm width

15% infill

2 walls

2 top/bottom layers

215 nozzle temp

60 bed temp

 

took 9 minutes to print.

 

[yellowshark 153]

As an aside, although germane, is it possible to over-cool PLA (assuming ambient temp. is OK)? I have always thought the recommended fan setting is 100%, once you have printed the first few layers.

[geert_2 557]

@yellowshark: You can overcool by blowing compressed air directly on the nozzle tip. This cools down the nozzle too much so it can not keep up heating, and generates a "temperature error" (I don't remember the exact description). I had that once in my overhang-tests, where I was testing the effect of additional cooling on the quality of bridges and overhangs. This was on a standard UM2 (non-plus).

 

I think layer-bonding could also suffer, similar to printing with ABS without front door and too much fan, but I haven't tested bonding strength, so this is a bit guessing.

 

However, putting a 30cm desktop fan (like those used in hot summers) at 2m in front of the printer, at its lowest speed, gave excellent extra cooling without triggering errors for PLA.

 

@paulrhee2002: I do see some horizontal gaps, but I am not sure if this would be underextrusion, or the lower layers sagging due to still not enough cooling? I would guess the last. While it is printing, maybe try poking into the model with a tiny pin or screw driver, to see if it is hard or still weak? Keep watching what happens (don't let this print unattended).

 

I still do think two top layers is not enough, unless you use +70% infill. But then that would greatly increase cooling problems, since all that infill-heat has to be removed too. At such thick layers you are faced with the dilemma that you need lots of heat to get enough plastic molten in time, but at the same time due to the thick layers, you can't remove the heat from the print fast enough.

 

When using only two top layers, the first one is going to sag a bit, and the second one can't fill up all the gaps. I would suggest you try 4 top layers and compare.

 

Since this is an area where we have no experience, you will be pioneering a bit. So keep posting your results, they are very welcome.

 

[yellowshark 153]

Lol @geert_2 that is changing the rules, I guess you could do an even better cooling job by putting the printer into a chest freezer 😁

[yellowshark 153]

It would be helpful I think if you reprinted with 0.3 layers. This would clarify the question mark over whether these really thick layers are or are part of the problem and also we could then evaluate some of your other settings

[paulrhee2002 2]

geert, I will certainly keep posting results and thanks for the input.  Yellow, I think your idea makes sense to print a .3 height test to see if its under-extrusion.  Smart people on here eh?  Awesome advice all.

I am trying to eventually print nylon which adds another layer of complexity and I need a flexible nylon in particular.

My first print failed badly.  Lots of smoke of water vapor coming off during print and it was terrible results.  My tevo black widow couldn't maintain a 150 nozzle temp.  Gave me some kind of temperature fail message and stopped printing.

Guess I have to change my printer...

 

[paulrhee2002 2]

I am moving on to trying to print a shoe insole/orthotic with sainsmart flex filament.

 

the entire first layer printed pretty perfectly except some strands when the nozzle was traveling.  Might have to adjust my coast specs?

 

Anyway right when the print moved to infill on the 2nd layer, the filament stopped extruding.

I paused the print and put fresh filament in and it printed a few lines more and then stopped extruding again.

 

Help!

The following are my settings and some pics

1mm nozzle:

.8mm height

1mm width

3 wall lines

15% infill

print temp 220

plate temp 60

print speed 10mm/s

 

I attached pics of the front of the insole where it stopped printing the 2nd layer, I reloaded the filament and it printed a couple more lines before the extruding stopped again.  I have no clue as to why that would happen!

 

I also attached pics of the filament after I pulled it out.

One thing to note, i tighten all the way the wheel that keeps the filament against drive wheel and was wondering if that's too much or would that affect it negatively at all? 

 

Please remember I am using a 1 mm nozzle.

Thanks in advance for any advice!