illuminarti
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Posts posted by illuminarti
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I'd be interested in a set too. Some of my original UM ones have the bore distinctly off-center.
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Oh, and yes, I think that the thing labelled 'heater' in your picture in fact isn't. At least on my slightly earlier electronics there isn't a connector there, just some solder pads labelled 'LEDs' (and that's where I have my LED light strip connected to).
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I don't have this same version of the electronics, so I can't compare directly. I do know that the brown-orange-green connection that is hanging loose there is for a second temperature sensor if you add a second extruder - it should correspond to a brown-orange-green connector that is hanging loose on the head.
I think that's the only connector or wire that can be unconnected. The heater is indeed a two-wire connection... but it's the fabric covered one that is supposed to connect to one of the green terminal blocks on the board.
Do you have any other loose wires? It would be a good idea to make sure all the connections are seated tightly on the electronics board, and at the head.
Do you get any messages on the Ulticontroller when it fails to heat?
Also, I presume you do have the printer power supply plugged in, and aren't just trying to run it over USB power.
Another thing to try might be to connect the computer over USB, and connect with Cura or Pronterface/Printrun and see if you get any error messages displayed when you try to print?
Also, if you haven't already, go ahead and open a ticket with Ultimaker Support.
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I agree that the exact results are going to vary with different filaments - both because of their fluid characteristics when molten (depending on colorants, additives, etc), and also due to their mechanical characteristics at the drive end. There are probably two different-but-related effects that need to be considered - both the ability to actively drive the plastic forward, and the ability to stop it slipping backwards (i.e., push harder, and hold on better).
A better extruder design would certainly help with the under-extrusion, and probably alter the maximum throughput rates too, but it doesn't alter the fact that most users have the current design, and are probably going to experience problems with under-extrusion. Nor does it alter the fact that there is an active limit to the amount of plastic that can be extruded per second, and we need to pay attention to that when selecting slicing parameters.
The plastic I was testing with is a sample batch that is not yet commercially available.
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Hi Paul!! Welcome to the forum! (Nice to see another Brit on the forum - I'm from Nottingham, but live in the US now.)
You should be able to preheat your nozzle by selecting 'Preheat PLA' from the Prepare Menu. I presume that's what you're selecting, so it's a bit odd that it isn't working. (Although I think there's another place that appears in the menu structure (under Control -> Temperature) - but thats for tweaking the settings for the preheat, not actually making it happen).
The chances are that the gcode for the test objects already includes the necessary commands to heat up the head. (You could try looking at the files on your computer - check for an M109 command somewhere near the start. If so, then you don't need to preheat... and worst case, the printer should refuse to try and extrude if the head isn't hot, so you shouldn't hurt things if you just try to print some of the files. The Ulticontroller should display a 'Heating' message... and the temp display should show 25/xxx (where xxx is whatever the chose temp is for the file, and the 25 part should start rising as the head heats up). Heating to print temp generally takes about 2 mins. Once it reaches temp, the print will start.
Which doesn't solve the 'Why doesn't the preheat command work?' question.... but will at least get you printing :-)
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As I have recently mentioned over on the Google Group, I've been doing some testing of extrusion rates (measured in terms of cubic mm of plastic per second), and how they are affected by print temperature. In particular I wanted to find the maximum sustainable extrusion rates for my Ultimaker.
I was able to find these limits, but I also noticed something else interesting - that at virtually all extrusion rates, the v2 extruder drive seems to exhibit under-extrusion of as much as 10 or 20% - amounts that gradually increase as the extrusion rate goes up.
This seems to be due to back pressure in the print head causing the filament to slip backwards during extrusion. Even though the filament isn't getting damaged in the ways that I normally associate with head blockages and extrusion problems, the spacing of the teeth marks on the filament becomes smaller at higher extrusion rates.
Effectively, it seems that the necessary steps-per-e parameter changes as we print faster. You can find the full details here:
http://www.extrudable.me/2013/03/29/exploring-extrusion-variability-and-limits/
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I've never had to do it either, but I think you could heat it up with it sat with the nozzle opening facing upwards, and just poke a thin piece of wire through the hole to push any foreign body away from the tip, and then scrape it out from the other end.
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Cura has some problems with thin walled objects, which can tend to lead to gaps in narrow parts.
If you have control over the model itself, and it's something that needs a uniform thin wall, like a box or a cup, its generally best to have the model be a solid block, rather than actually modeling the inside and outside surfaces of the wall. This way you have more control over the printing by specifying different wall thicknesses in Cura, and setting the infill to 0%, so you just get the outer wall.
If your model actually represents the thin walls in its STL, then things get more complicated, because Cura has to try to fit the wall thickness you request in Cura within the limitations of the space in the STL file.
Generally speaking, you want the wall thickness to be an exact multiple of the nozzle width, so that the wall gets printed just using loops that touch one another, without leaving a gap.
For instance, if your nozzle width is 0.4mm (the UM default) then a 0.4mm thick wall will use 1 pass, a 0.8mm wall will use two passes, etc. If your wall thickness is specified as 1mm, while your nozzle is still 0.4mm, then it might do two 0.4 mm loops, and then be left with a 0.2mm gap in between which is too small to fill. In this case, what Cura actually does is pretend that the nozzle is 0.5mm wide, and try to do two 0.5mm wide loops. But due to a bug, it doesn't get it quite right... (see http://www.extrudable.me/2013/04/08/walls-and-nozzles-and-cura-oh-my-or-quickprint-is-broken/)
So what to do... well, ideally, make the walls be an exact multiple of your (0.4mm) nozzle width. Either by updating your STL if the wall thickness is modeled into it, or by setting a 0.8 or 1.2 mm wall width in Cura. If it's critical that the wall be 1mm thick, or that's what's in the STL and you can't change it, then try setting your nozzle width in Cura to 0.5mm, to preserve the exact ratio. (If you do it manually, it avoids the bug mentioned above). Cura will then extrude slightly more plastic which will get spread out under the head to make two 0.5mm beads of plastic, for a total width of 1mm.
Or, the other alternative is to use a different slicer - perhaps Kisslicer - that doesn't have the problem with filling small gaps, and fake nozzle sizes. But, to be honest, Cura can probably - still work for you: just adjust the nozzle size and or wall thickness so the latter is an exact multiple of the former.
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Sorry for seeming pedantic about it, but the settings do matter. :-) For instance, if you're printing with 'high quality' settings from the quickprint mode, then iirc, you're printing 0.1mm layers, not 0.2mm layers, and I don't think any of those modes use retraction at all. The wall thickness you specify could make a difference as well, if it's not an exact multiple of the nozzle width. (See my blog post here for more details about the effects of non-standard wall thicknesses in current version of Cura and how it can cause problems).
It doesn't sound like you're printing at speeds that should be causing problems by themselves, so it could be an issue in the assembly of the hot end... most likely in the interface between the bowden tube and the teflon part I think, although in general new hot ends are really pretty reliable, so long as you aren't printing very fast, or very slow.
What is your procedure when you're getting ready to print again after fixing a problem? How do you prime the hot end with plastic? Do you manually insert the filament, and turn the drive gear by hand, or are you using an ulticontroller or Cura etc to drive some plastic through the nozzle. The latter should be avoided because it can quickly overload the hot end (default extrusion speeds are much faster than the nozzle can handle). If you simply turn the gear by hand, you can feel resistance when you are turning too fast, and can slow down a bit. This avoids forcing molten plastic back up towards the bowden tube. (I've had this happen, the one time I thought it would be a good idea to use the ulticontroller to help load filament - I got three clogs one after another even while trying to get ready to print again).
The Cura defaults, as set by the first run wizard.
Print speed 50 mm/s, Temp 220, Filament diameter 2.89, packing density 1.0, retraction enabled, 0.2mm layer height, various wall thicknesses depending on the print.
The only setting I have changed from the defaults in prints have been wall thickness, bottom top thickness, fill density, and support settings. Often I am just printing with the basic High Quality setting. The problem does not seem to be related to those particular settings, especially when you consider that after I cleaned the second clog out, it reclogged within seconds of starting the first print (which leads me to believe perhaps the hot-end did not get put back together again correctly in some subtle way)
The printer flawlessly printed for 3-4 days, probably about 30 hours of printing, before the first clog. The only problem I had was an occasional first layer or perimiter not adhering; stopping the print and restarting it would always fix this.
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I was very, very confused, until I realized this is an 18 month old thread....
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What default settings, specifically? What speed, and what wall thickness and layer height? Those settings can make a big difference to the amount of plastic you are trying to extrude per second, and can cause problems - I've seen several users now who had huge problems (to the point of 'I'm gonna throw this $#^#^$% printer away') until they found some speed settings that didn't ask too much of the printer.
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In addition to what Calum asked, what print settings are you using to slice? How fast, and what layer height, nozzle width, wall thickness settings?
Also, when testing extrusion, I highly recommend only turning the big gear wheel by hand. Don't use the ulticontroller, because I find that can very easily end up forcing too much plastic through the head too quickly. That can immediately cause more clogs by increasing the pressure in the head and causing molten plastic to squirt back up into the colder parts of the head. If you turn it by hand, you'll start to feel the back pressure as you turn, and can slow down a bit.
Also, when you have extrusion problems, be sure and remove the plastic from the bowden and check that it's not damaged. Cut off any damaged parts that might have been chewed up by the extruder drive. They will just cause more problems.
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As noted on the other thread, I'm not sure that you can set different steps-per-e for each extruder directly. But also, the difference in steps-per-e that you mentioned 860 v 835 is only a few percent difference in extrusion rates. I doubt that would cause enough under-extrusion to be really noticeable. I suspect that the problem you are seeing is more along the lines of the slicer not properly keeping track of retractions and filament positions when switching between nozzles, so that maybe it starts trying to print with an extruder that hasn't been re-primed after it's last retraction? At the very least, that's something to check... I don't think the firmware is tracking filament position per extruder.
Also - Cura defaults to printing support very under-extruded anyway - that's not what you're seeing is it? I presume if you are using a soluble or otherwise easily-removable support material, you'd probably want 100% support density. (Hmmm... maybe that's also a way to compensate for different steps per e - perhaps in Cura you can specify a density for the support that is over 100%??)
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Looking at Marlin... I don't think there's a way to define the steps-per-e separately for each extruder. I may be missing something... but it looks like the steps-per-e and the 'flow multiplier' settings in the firmware are just single values, not per extruder.
So If you really have different steps-per-e, I think you'd need to use some sort of 'per material' extrusion multiplier/packing density adjustment, so that the gcode is already asking for different amounts of material, rather than having the firmware compensate. I suspect Kisslicer can do this - but not sure about Cura.
Finally, it looks like in Marlin, the current E position isn't tracked separately for each nozzle. So when changing between nozzles the slicer will need to take care of resetting the E position to zero and/or dealing with any retraction and de-retraction issues (assuming that you're using absolute E coordinates). Otherwise, the slicer may end up specifying filament moves based on the position of the 'other' filament.
All working now, built my own firmware and switched to CURA 12.12A
However next problem is how to set the "steps per e" for extruder 1 and 2 independantly...
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There is no one right setting for a high quality print. Therefore no one can answer that question meaningfully. It depends what you are trying to print. Different things need totally different settings.
There are clearly things wrong with your prints that are nothing to do with layer height or top thickness. Changing settings like that won't fix these problems. You're under-extruding, getting really bad stringing due to not using retraction, and I'm not sure there aren't x-y accuracy issues as well. And that's just from a few seconds glance at the pictures.
My apologies for 'forcing' you to go off on what you evidently consider a wild goose chase. I was under the mistaken impression that you were wanting the community to help you to get the best out of your printer. I understand better now what you want.
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No, I wasn't offended... but I think maybe you're missing our point.
I don't know what you're trying to print... or what you expect, but there's no particular reason that 0.2mm layers with a 0.6mm bottom/top thickness 'wouldn't cut it' or should result in 'cracking'. A thinner layer height is going to reduce the visibility of the layers, and it means that you are extruding less plastic per second, all things being equal, and that can help avoid certain types of problems. But in general, other than making the layers less visible, and helping preserve slightly finer detail in the Z direction, thinner layers aren't going to make the outcomes radically different, or solve problems.
Which is why George and I said what we did - if you think there are problems with your prints at the default settings, then lets take a look at the prints that you got, so we can help fix them. If you are having problems with 0.2mm prints, then most likely the solution is to tweak things about the hardware of your printer, rather than to start changing print settings.
I believe you two have taken it the wrong way. Never, was I disappointed in the machine. Nor were my prints resulting to poor results. If I've somehow offended either of you with my topic, I didn't mean to. As a matter of fact, I love this machine and I think it's the sickest thing ever. It's my first 3D printer to own and some of the other machines I've seen like Printrbot, the Afinias and the POS Cube don't even come CLOSE when it comes to the quality and speed factors (although I do plan to purchase a Rep 2 in the near future). But this wasn't a review of the machine. My question was regarding what your Cura print settings are for the finest quality of printing. I'm currently printing at default settings with the exception of 0.1mm layer height and 0.3mm B/T thickness settings. 0.2mm height and 0.6mm B/T thickness wasn't cutting it, and some of the prints resulted to cracking up.
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If 5mm/s is fairly slow, what do you consider to be fast? :-) What size nozzle opening are you using?
I've printed several 35 hours jobs that were printed fairly slowly (under 5 mm / sec filament feed rate) and I still had no trouble with heat migration or jams.
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Not to be too pedantic, or take this too far off topic, but 'spackle' is the word in American English. :-) British English doesn't really have a word, but it's mostly known by the brand name 'Polyfilla'. Bill Bryson wrote a great essay about just this thing, and the resulting added difficulty of transplanting continent...
http://books.google.com/books?id=tpU69-XkjDEC&pg=PT9&lpg=PT9&dq=my+wifes+people+call+it+polyfilla
He was returning to US, having spent most of his adult life in the UK. I moved here as an adult, without even the benefit of a US upgringing, but I can totally relate. :-)
@Pablo: spackle is the word in English. Sandlaster with the right media would probably work really well. Maybe walnut shells? I used to use one for decapsulating ICs where more precision than a Dremel was required.
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In what ways is the quality disappointing you? I have no way to know what your expectations were, but if your printer is working ok, and your expectations were even half-way reasonable, the I'd expect you to be pretty blown away with you new printer. I know I certainly was. So I think there's a reasonably good chance that there are some problems that need fixing, and I think it would be a good idea to work on that a bit before trying to get more adventurous.
There's no one simple answer to the question of what settings to use. Different objects need different settings based on the type of object, and the challenges that each has. There are not really any simple answers as to what settings work best. It all depends on the object, and how well calibrated your printer is. Generally speaking, slower prints will work better than faster ones, and thinner layers will look better than thicker ones. But both of these things can be taken too far... its rare for me to print much thinner than a 0.1mm layer height, or slower than about 50mm/s. But, there again, sometimes there are good reasons to. The ultimate challenge is to find the settings that give you a print whose quality meets your needs without it taking any longer to print than it really needs to.
In general, the difference that settings makes should be in making a reasonably ok print, into a really good print. That's the intuition that you need to develop as you get more experienced. Rather than randomly trying different settings, what might be a better approach for you would be to post some examples of things that you've tried to print, and the results that you got. That way we can help you calibrate your expectations first, and then your machine :-) Chances are that the folks here can help to identify a) any technical problems that might be spoiling your results, and/or b) suggestions as to how to tweak your settings or tune your printer to get better results. And then you will need to begin a process of careful experimentation as you begin to learn how the different parameters - mostly speed, temperature and layer height - affect the outcome of each print. I highly recommend taking lots of pictures, and keeping a note book of the different things that you are trying. It's a great way to begin to identify a middle ground of 'not bad quality, and not unbearably slow' that you can then begin to refine from.
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I am always slightly bemused by the angst over bed height and level. I can see why it might be especially critical for very thin layers, but when printing in the 0.1 to 0.2mm layer height range, it's just not a big deal for me at all. I never have to adjust the z end stop, and I occasionally quickly adjust the bed corner spring screws using a sheet of paper as a feeler gauge. And then it 'just works'.
I'm printing PLA at 220-230ºC onto an unheated bed covered in isopropyl-alcohol-wetted blue tape. I add no extra layer height on the first layer, and normally print my first layer at 75 to 100 mm/s. What am I doing wrong??
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It's good that it's always a short move, because otherwise it would be a disaster. :-) Because it really *is* a print motion - if you do the math, that 'short positive net E' is exactly the right amount of plastic to print that segment at a 0.2mm layer height. So it looks like its intended to be a part of the print. And all of that plastic is going to get dumped at the very end of the move. Now, it probably doesn't matter much in practice, but I can't think of any reason for doing it this way. It doesn't seem to be a work around for anything... I think it's just a bug. It's one thing to make a design decision to retract whilst doing a travel move... but to go in the opposite direction during a print move is only going to impact print quality negatively.
The last line of the code is for a very short X-Y movement with detract ("push-on" in nf-speak), including a very short positive net E (ending very slightly beyond the filament position before the retract). It is always very short like this. I don't know their motivation for combining the detract with a very short X-Y move, but it doesn't really constitute a print motion. Overall, it actually does work!
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While it's not an ideal solution, I don't think there's anything necessarily wrong with doing 'move and retract at the same time' (even without a proper G0) provided that the speed limit set on all the axes is correct.
But I do think that doing 'print and de-retract at the same time' (as Calin's sample code seems to suggest) is NEVER the right solution. With or without a G0, I can't see how that is ever going to work. The detract needs to happen quickly, while the print part needs to coordinate with the X-Y movement. How can they be combined into one movement?
Finally, since Netfabb are selling (through UM) an Ultimaker-specific version of Netfabb, shouldn't it do whatever Ultimakers do? Saying that UM's do it wrong is totally not a viable defense in that case.
Well, as I understood. The NetFabb people are pretty much blaming the firmware for not working correctly, and the UM users are blaming NetFabb for not implementing retraction correctly.
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NetFabb is trying to retract while moving fast. For this to work, you would need a "proper" "G0" command in the firmware.
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The thanks for getting to the truth of this problem should go to Paul, as he explained me what NetFabb was trying to do in GCode. And that the NetFabb people where complaining about a bug in the firmware. With my own knowledge I could fill in the blanks and figure out what the real issue is.
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Calin -
It's a little difficult to tell without looking at a longer section of code, but this gcode looks to be broken to me - irrespective of the Marlin fix.
What is happening here is that the retract happens as part of the fast move on the third line of your code snippet... F10800 = 180mm/s. So in fact, the move will be limited to be the slowest max speed of any of the axes that is moving - typically the extruder. So it will happen at whatever VmaxE is set to.
Then on the next line it does another fast move... presumably to wherever it wants to start printing again. The extruder position doesn't change; so the move happens at 180mm/s or the lower of VmxX or VmaxY as set in your firmware.
Then on the final line it starts printing again - moving at a slower speed this time - 20mm/s. But what is strange is that it never undoes the retraction before it starts printing. The full amount of retraction gets undone over the course of this first line segment,plus an extra 0.0011mm of filament. Now it's only a short move - 0.08mm - so that net extrusion of 0.0011 mm is the right amount of plastic for the whole of that segment, assuming a 0.4mm nozzle and 0.2mm layer height. But that should be happening over the length of the first segment equally - whereas this gcode is going to dump that little bit of extra plastic at the end of the move (because for most of the move, it's going to be busy unwinding the retraction, and not actually extruding anything.) Since this is a very short move, it probably doesn't make much difference - maybe a slight blob - but if it was a longer first segment, you'd be more likely to get a noticeable under-then-over extrusion pattern
Maybe Netfabb is doing something to ensure that this de-retract move is always very short, but I can't see it's ever going to be good to have gcode that starts printing before fully undoing the retraction.
I'm also not really seeing why the speed fix in Marlin would make a difference, except to the extent that the above code would effectively have been limited to retracting at (probably) half the VmaxE speed you had set in your firmware. With the fix, it's going to operate at the full VmaxE speed - and that may simply be too much for the motor to deliver if your VmaxE is too high.
So, I think there are three takeaways here....
1) With or without the Marlin Retraction Fix, Netfabb is relying on your retraction speed being limited by a reasonable VmaxE setting in the firmware.
2) Netfabb's de-retraction code may be broken (at least the code you provided suggests it may be), because it de-retracts during the first print move, not before it.
3) With the Marlin fix in place, you especially need to make sure that your VmaxE setting is reasonable, because you'll no longer be protected by broken firmware that usually only delivered half (or a quarter) of the VmaxE that you had set.
Thanks, Daid. I bumped the limit up to 25 mm / sec and it seems to be working on a short test.
Illuminarti, Yes--nf seems to retract at a high speed but I've found that the user "pull-back speed" setting (RPM) doesn't work in nf. Changing the setting does not result in a change in the gcode produced. The F value in the gcode remains 10800, regardless of the setting in the nf "Manage Materials" >> "Speed and jump settings" tab:
Disabling this setting may be at least partially what Alexander referred to as a workaround.
G1 X179.4590 Y17.8500 Z0.0400 F1200.0000 E14.3443
(retract -2.88)
G1 X179.7556 Y19.5524 Z0.0400 F10800.0000 E11.4643
G1 X182.1463 Y33.2764 Z0.0400 F10800.0000 E11.4643
(retract 2.88)
G1 X182.1465 Y33.3587 Z0.0400 F1200.0000 E14.3454
Just assembled, Great machine, try to improve
in Coffee corner
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Welcome!! Those are pretty nice first prints, well done! But yes, there's always room for improvement.
What temperature are you printing at? To get better overhangs - reducing the droopy bits on the robot - you generally want to print slower, and cooler, and be sure the fan is on.
Where the prints have some gappy parts, that may be due to under-extrusion - not laying down as much plastic as you should. Increasing the temperature might help a bit, as might slowing down a bit. You also need to make sure that you are using the right filament diameter when you slice the object. Do you know the exact diameter of your filament? Cura defaults to 2.89mm I think, but that's rarely the right size - most commercial filaments tend to be 2.85 or even 2.8 in most cases. If that's the case with yours, then you'll be extruding less than you should, because Cura thinks that every mm of plastic that gets fed in is thicker than it really is - and that's how it controls how much gets extruded out of the nozzle.
As you can see from those two statements... there's no one 'right' print setting; you have to adjust for the object you're trying to print. There are competing needs of temperature, speed, and layer height that effect the end quality.
You might also check the tension on your extruder drive spring. The spring should not be fully compressed - on mine, there is about an 11mm length of spring between the body of the extruder and the head of the spring. Check the filament in the bowden tube after a print.... it should have clear teeth marks in it from the drive bolt, but not be chewed up or worn.
The 'normal' settings in Cura are a good starting point, so I'd continue to tweak things around those settings while you get the printer bedded in and understand it better - and get a feel for what sort of settings an object needs. If you have problems, it's tempting to think that the 'High Quality' settings in Cura - slower, thinner layer heights are the solution. And really they aren't. It's not higher quality in the sense of fixing problems, but rather just improving the finish - less obvious layers, and better handling of 'almost horizontal' slopes and curves. Even on 'normal' quality, with 0.2mm layers, you should be getting perfectly good results. If you aren't, then keep posting here and lets try to tweak the hardware and settings until you are.
Well done on getting started though! Those are some pretty nice first prints - you should be pleased!