I actually wrote a fairly long post about getting good prints on another forum. I've copied it below. You don't have to agree with it all - but I'd highly recommend reading through it.
Formatting got a bit lost copying and pasting it.
By knowing what these and the rest of the settings do you can get good prints out of most printers, like this on the Ender 3:
https://giant.gfycat.com/OrganicUnacceptableEgg.webm
Part Cooling: Your extruder and nozzle will have a fan on it that blows on the heat break and stops heat creep. But you also need a second fan if you’re printing PLA (and most others) to cool the plastic as it gets extruded. Let me be clear here: IF YOU DON’T HAVE A PART COOLING FAN STOP WHAT YOU’RE READING AND GET ONE. It is ABSOLUTELY needed, and your quality will be shit without it. If you don’t have one and need to print a duct to connect one then use a regular desk fan turned to full blast and point is as close as you can to where the part is printing. Turn the desk fan on before starting the print else it’ll cause the nozzle to drop temperature and it’ll set off the thermal runaway protection in the firmware.
Layer Height and Nozzle size:
I see a lot of confusion around these two things.
Layer height is the distance that the z (upwards) moves for each layer, so it is the thickness of the layer. To visualize this, imagine you were looking from the side of a vase and wanted to replicate the curve. First take a few thousand pieces of standard printer paper stacked up and make them match the curve. It’ll very nicely and smoothly match the curve. Now take planks of wood and do the same. Obviously it will still roughly follow the curve but it’ll be a very jagged edge.
Nozzle size is the size of the hole in your nozzle, and determines the horizontal accuracy. To visualize this, think of a clutch pencil (with the tiny graphite tip). With it you draw one single layer of a print. It can perfectly define all the sharp corners and such. Now take a blunt permanent marker and draw the same shape - obviously the corners are now much more rounded and less defined.
So when someone says “you have such a big nozzle, you can’t print at 0.1mm layer height” it is totally wrong. They are completely different things and are totally independent, except for: Having a bigger nozzle means that a bigger tube of melted plastic is coming out of the tip and thus you can achieve bigger layer heights.
Layer Heights
0.3: Unless you have a bigger nozzle than the standard 0.4mm that comes with most printers, don’t do this.
0.25: This is about the biggest you’ll want to ever go.
0.2: This is my standard for functional parts where you want it strong and don’t care too much about the look.
0.15: A good middle-ground for quality and speed.
0.1: My standard for most prints I want high quality. So busts, models, little characters, etc.
(There are many factory that go into this, but here is the overall summary
Anything below 0.1: Unless you have some very weird z rod pitch or stepper, it is very likely you can achieve below 0.1mm layer height. The problem comes in with your extruder. At 0.5mm layer height, unless you are printing stupidly fast, the extruder gear turns VERY slowly. If you hold your finger on it you’ll actually feel the steps. This ends up meaning that it can’t push the filament accurately enough to follow what the print head is doing, and your quality may actually be much lower than something like 0.1. I was comfortably printing at 0.07mm layer height on the i3 mini, but it isn’t ideal, and I wouldn’t go lower.
So assuming you want to increase that accuracy (and not going into the fact that at 0.05mm layer height you’ll never finish a print between loadshedding times), you have two options.
- Get a 0.9 degree stepper motor that is more accurate.
- Get or print a geared extruder. This is the better option IMO. You could look at making something like a gregs wade extruder, or the DIYE version called the Charlstruder. Or if you want to buy one you can look at the E3D Titan - it has a 3:1 ratio which means it will spin 3 times more than before to do the same amount of filament movement (i.e. 3 times more accurate (ignoring other factors)).
Extrusion Width:
This is the width of the tube of melted plastic that it spits out. Obviously software can’t change the nozzle size, but this setting effects the amount of plastic that comes out, and the more plastic the more it squishes outwards, and the thicker the line will be. I like to use 0.4mm with a 0.4mm nozzle, but S3D defaults to 0.48mm, and many people use that.
Retraction:
Retraction is something you absolutely have to use with most filaments. Just about the only time you don’t use it is with filaments that like to jam when you do.
S3D:
Cura:
(in Material tab)
Retraction Distance: The distance that the filament is pulled back. In the picture I’m using 7mm, this may be too high for your setup and cause jams. With a bowden setup you should start at around 4mm.
Retraction Vertical Lift (z-hop): Sometimes when you print, small edges will curl up and the nozzle can hit those. That can lead to either layer shift or pulling the whole part off the bed. I would HIGHLY recommend you always keep this enabled. It is super super important. It does slightly increase stringing, but it will absolutely stop a fair amount of failures. I find 0.2mm is enough, but you may want to go higher (the default in Cura is above 1mm AFAIK).
Retraction Speed: The mm/s speed that the extruder motor will spin to retract and un-retract the filament. I’ve found 100mm/s to work well, your setup may differ. On some machines the firmware will be set to limit the max speed of the extruder below this so your values will get ignored. On the Ender 3 it is set at 25mm/s by default - to change it goto Control > Motion > max estep, change it to 100, then go back one menu and click Store Settings.
The following are less important and will require more calibration on your end
Extra Restart Distance (Retraction Extra Prime Amount): After retracting the filament when it gets to where it wants to extrude again it will un-retract. Sometimes this causes a blob on the print because it pushed the filament forwards too far. Here I’m saying that it should push forward 0.1mm less than it wants to.
Coast Distance (in Experimental tab in cura): Sometimes simply retracting the filament isn’t enough to stop the filament from oozing out while the print head moves - this setting tells it to stop extruding x distance from the end of a line. DON’T use this if you’re using Linear Advance.
Wipe( Outer Wall Wipe Distance in Cura): This is similar to coast, except this will still extrude to the end of a line, but then it will stop extruding and “wipe” the nozzle along a previously printed area to use up any filament that is trying to ooze out.
S3D
Cura
Top/Bottom Solid layers: This is the number of flat layers on either end of a part. It doesn’t really matter for fully organic shapes, but matters a lot for things with flat surfaces. Depending on your layer height you’ll need to pick a different value. For instance, 0.1mm layer height is spitting out much less plastic so it is harder for it to perfectly cover up the gap below, so you’ll want like 5 top layers. With 0.2mm layer height you could probably be fine with 3. In Cura you can set a thickness value instead of layer count.
Outer Shells (Wall Line Count): This is the number out outside walls (that aren’t top/bottom) that it prints. The more there are the stronger, but the longer the part will take to print. I generally do 2, but on models with big overhangs I’ll go up to 3 or 4.
Outline Direction ( Outer Before inner Walls): This tells it whether to print from outside in or inside out. If you want dimensional accuracy then you should go outside to inside. But I basically always keep it on inside to outside - this is because if you go inside to outside then you can achieve much bigger overhang angles because there is more to extrude on top of. When doing inside out, increase outer shells to 3 or 4 and you can get some pretty insane angles (like the deadpool bust arms).
External Fill Pattern (Top/Bottom Pattern): Just use Rectilinear/Lines, the others have some use cases but generally will make your part look bad. Zigzag in Cura can look cool depending on the part.
Infill Percent: The percent you need is based on your layer height and how strong you want the part to be. Generally I keep below 20%. With a 0.1mm layer height you may need to go a bit higher else the top layers won’t be able to cover up properly. It is hard to explain but you get a feel for it.
Outline Overlap (Infill Overlap Percentage): This determines how much the infill and the outside shells overlap to encourage bonding. I like to keep it quite high between 40 and 70%.
Starting script:
You’ll want to prime your nozzle before printing - that means to get the plastic melting out of the nozzle else you may underextrude the first bit of your part. By doing a priming line like below you’ll also wipe away any gunk on the nozzle.
I would recommend taking a tissue and wiping the nozzle manually while it is hot after any long prints though since there may be gunk right up the sides of the nozzle.
Use this as your starting gcode:
G28 ; home all axes
G1 X5 Y10 Z0.2 F3000 ; get ready to prime
G92 E0 ; reset extrusion distance
G1 X160 E15 F600 ; prime nozzle
G1 X180 F5000 ; quick wipe
Temperatures: For PLA you can use about 190 to 220. If you’re printing fast you’ll want to be around 210, but the higher the temperature the more stringing you’ll get, so for high quality prints I like to do 190.
Bed temp should be 60 for PLA, but you can go anywhere below that (or off) depending on your build surface.
S3D
Printing Speeds: Speeds depend on the printer. Some printers can go really fast because they are super sturdy, while others need to go a bit slower. In general the slower you go the better the quality of the surface as it’ll have less ghosting/wobble/vibration.
For high quality prints on the Ender I use 40mm/s with outer shell done at 50% of that. For just general printing I use 60mm/s.
X/Y Axis Movement Speed (Travel Speed): The default for this is usually fairly low. I like to bump it way up to 200 to 250mm/s depending on the printer (200 for Ender 3). By making this really fast you spend less time just moving around, and it helps a lot to reduce stringing. However having this high also increases the risk of the part failing if it hits plastic that has curled up, so if you make this high you have to also enable zhop (which I’ve already told you to use anyway).
Supports: To ensure that the small bits of supports stick to the bed make sure you set it to print one solid layer below supports. I also like to set about 5 layers of 70% dense supports where it touches the part to make the quality better in that area.
Calibration: Watch this video and follow the calibration stuff to make sure your extruder is pushing out the right amount of filament, else all your settings are pointless. If you do that extruder calibration multiple times and get different results every time then your extruder gear is slipping. You either have a small nozzle blockage, or you need to upgrade to an extruder with an adjustable tensioner.
The basics of that calibration video is: heat the nozzle, measure 100mm of filament from the extruder body towards the roll. Tell the printer to extrude 100mm and see that your 100mm mark moved 100mm. If it moved too little then increase the extruder steps per mm, or decrease if it is too much.
How to tune your slicing settings featuring Ender 3
OK, that’s it for now. I’m sure I’ve missed stuff, but this should give you a basic run down of where to start.
