UM2(+) Bad quality printing with bigger line width.

[my3DBr 4]

I am trying to print with 0.6 to 0.8 line width with serious compromise to quality. Lines are far from each other and no water tide at all. 

UM2 with DDG Bondtech, 3D Solex matchless 0.4 nozzle. PETG at 230 to 240 nozzle temp. Draft 0,2mm height. Speed custom 60. Temperatures over 230 do produces bad quality cubes related to excessive temp, but still with all space between lines. At the top, central lines are not touching wall lines, wall lines are afar from each other. Even the lines of skirt are apart from each other.

Flow at 100 for everything but top/bottom, default CURA (97%, don't ask me why).

I recently made some replacements on parts of the feeder: changed the stepper motor gear from plastic to metal - although both of them identical dimensions and teeth number - 11. Did NOT made E steps adjusting, after.

Do I need to? What can it be? What is your experience with line width?

Arquivo Comprimido.zip

[Smithy 1,144]

When you want to print with line widths like 0.6 or 0.8 you also have to change the nozzle. You cannot print 0.8 line width with a 0.4 nozzle. That's the reason why there are different nozzle sizes available.

[my3DBr 4]

Hello Smithy. Sorry to respectfully disagree. There is, e.g., a well known video from Stephan - CNC kitchen talking about line width and its influence on print's characteristics. every nozzle being able to extrude even more than 200% it's size. There is also a plenitude os data and texts. The triad Temperature, Flow and Speed. Just a matter of reaching the balance. Of course there is the limits of the printer, bit I do believe my printer is able to do that.

Example: https://dyzedesign.com/2018/07/3d-print-speed-calculation-find-optimal-speed/ where: 

Maximum line width

The maximum line width will depend on your nozzle flat width. Manufacturers should specify this dimension to configure your slicer accordingly. The maximum line flat should be equal to the nozzle flat. Note that any overflow will have an impact on top infill quality, as it will tend to rise around the nozzle.

Considering a 0.40mm nozzle having a 0.80mm flat with a 0.20mm layer thickness have a maximum line width of 1.00mm.

 

Going bigger!

However, nothing is stopping you from going a lot higher or lower. For example, the two images below are the same exact Gcode, one ran with a 1.00mm nozzle, the other with a 0.40mm nozzle. The line height is 0.50mm and line width is 1.50mm.

Printed with a 1.00mm nozzle

Printed with a 0.40mm nozzle

As you can see, there is barely any difference. As long as the 0.40mm nozzle flat is within the margin, the result is pretty good. In this case, the layer height was 125% the nozzle diameter.

Smaller nozzle can still extrude large lines, but have more flow restrictions compared to larger nozzles. The speed must be decreased to get the same results.

[geert_2 557]

I think of it like a paint brush: if you try to paint strokes twice as thick as the brush (in one single pass), it is going to look irregularly and messy, even if the brush would be followed by a sort of scraper to flatten and spread the paint. Idem if you try to print strokes only half as wide as the brush: they will be very irregularly too. You will get the best results when the paint strokes are as wide as the paint brush.

 

The molten plastic is a thick liquid. By increasing pressure or reducing speed, you might be able to squirt out a lot more liquid than usual, but it is going to flow in all directions, out of control. Liquid tends to flow into the path of least resistance, and once a flow is going into one direction, the rest behind it easily follows, creating a stream, but leaving the rest of the area uncovered. And vice-versa, if you want to print too thin lines, the flow is going to stutter and produce irregular lines and blobs too, like a thin leak that drips, thus in an on-off-on-off-... flow.

 

Similarly, if you would try to print layer-heights of 0.8mm out of a 0.4mm nozzle, it might less or more work if the molten plastic would not leak away too much, but it is going to look very irregularly and messy. I once tried 0.4mm and that already looked poor.

 

[Smithy 1,144]

3 hours ago, my3DBr said:

The triad Temperature, Flow and Speed

I would say that 60mm/sec is a way too fast for what you are trying to do. Start with 30mm/sec and go up if that works for you. Set the temperature to the upper end of what is still acceptable and then you can also increase the flow to see if that helps.

 

But overall that is just an experiment, I would not print a model with such settings, the result could not be good, also if your picture shows something else. I still would say, print with a bigger nozzle or print it with 0.4 or 0.5 if you want and accept the longer print time. In my opinion it is not worth the effort and the compromise in print quality. Nozzles are also quite cheap.

 

 

[GregValiant 1,251]

I always look at it with a "jaundiced eye" when one of those types of blurbs is on a site touting their own products.  Settings like they are taking about might be possible with their $169 "Pro" hot end.  The chances of one of those ending up on my $197 printer are not good.

I did experiment with line width and layer height when I got started.  Now I just stick with what works for me.

 

[my3DBr 4]

Right now my enders are apar with the UM2, fact - although printing slower. I've done 8 or 10 calibrations cubes today, messing around with everything possible. Dissasembled and re assembled the Feeder, re done de e steps (witch contrary to plain math is not what Bondtech says) and...no good un til now. Perfect wall, top horrible. Could it be Cura's fault?

[GregValiant 1,251]

Well, probably not.  In this case your question really is "Can Cura do simple math?"  It's one of those things that people call into question when their settings don't work.  I'm not saying Cura doesn't have some bugs in it (in fact I know it does) but at the heart of the matter, calculating the amount of plastic to deliver for any specific extrusion is really very easy stuff.  Cura knows the volume of the extrusion and it knows the diameter of the filament.  Solving for the mm's of filament is a piece of cake.

As your research has shown, that simple math evolves into complex equations when the rate of pressure buildup and the rate of pressure fall-off in the nozzle come into play.  The math, mechanics, thermodynamics, material science, and other disciplines required to describe filling that little rectangle (or oblong if you prefer) below the nozzle is both very simple and very complex.

It can be unrelated things as well.  Did you check the nozzle for burrs on the inside diameter before you put it in service?  What is the angle of the countersink between the 1.80 upper ID and the 0.4 ID of the lower portion?  The speed of the material through the nozzle causes little things like that to come into play.  Is your thermistor accurate?  The one on my bed and the one on my hot end can't even agree on room temperature.

The two things I know for sure are that "Entropy always increases" and "100% of the PLA produced on the planet will end up in landfills.".

[my3DBr 4]

Well the PLA will be there for a loooooong time.

Any hints about what am I doing wrong? 

E steps are correct. Temp is even high, at this speed the details on walls are suffering. At the top walls are not touching, gaps everywhere, but flawless flow on walls.

Nozzle Temp 225-230, Flow bumped to 100%, Fans at 100%, speed 40.

Remember: 0.4 nozzle and 0.8 line width.

 

Cube0.8Flow100Speed40.gcode IMG_9780.jpg.zip

[GregValiant 1,251]

I tried to print that file.  Good luck.  When I aborted the print (E motor was skipping steps) and the nozzle rose - about 40mm of filament escaped before the pressure fell off and that was after a 5mm retraction.

Good luck with it.  As I said, I'm going to stick with what works.  .2 layer height and .4 line width for most stuff and at 75mm/sec with 35 for the outer walls.  I do use .6 line width when I'm using Vase Mode because the prints are stronger.

 

[my3DBr 4]

Hahahaha welcome to Ravenloft.

I've just printed some hollow cubes, 1 to 4 walls. Line width 0,8.

The 1 wall cube came perfect, walls with the right width, no skipping steps. But, in 4 walled cubes, the internal wall come out with 0.5mm - they are so spread that is possible to pinch the pachymeter inside.

I was reading and article about flow in 3d printing (5Axes-calibration shapes) to have some idea of what you were talking about earlier. Well I just can't understand why it  is happening.

Doing some thinking about this 200% size of nozzle Stephan's video, maybe I have to remember in which printer he did it. In a volcano with a orbiter maybe, so, its different. 

I thought I could cope near if spending some money with Bondtech extruder, 3dsolex heat block and nozzle...but maybe you were right from the beginning. 

Holy damn, my ultimaker is not even possible of printing a square square. I am struggling for 2 years now, revised it entirely, opened so many discussion around here, and no, no square cubes. It always the same deviation - X 20.22mm Y20.59mm. 

I am tired.

 

[my3DBr 4]

Hello everyone.

I have news!

My printer had a Achilles heel: I never ever thought about changing the heater cartridge...it was the old original, 25W if I am not wrong.

It happens I am a often customer from AliExpress and had a 40W heater lying around. 

Here comes the story: as you can imagine this is not a 3DSolex or other know brand, so I had two problems: it was short for the Extended version AND the cartridge is skinnier  (0.1mm) then the original - the hole in the heater block is 5mm, the good quality cartridge 4.9mm, the Chinese 4.8mm (I've read that it is proposital since Chinese or second quality blocks have problems with accuracies). So I had to sold wires (from another cheap cartridge) and do a little smashing with pliers so it deforms a little bit.

Then I've put some thermal paste to fill the gap and voialà, all set. 

Everything working grate! PID tuning and some stress tests, no extruder skipping, everything good!

 

I went searching all again for good quality heater cartridges and had the same problem, even on first line sellers: they don't tell the wire length.  How to know if it fits the Extended version? Send some emails around to see what happens.