3d Printing without Stringing and Understanding 3d Print Failures

hi there sir Shapiro of the dr. max Channel and today we're going to talk about how to go from prints that look like this filled with stringing to prints that look like this that are almost perfect and along the way we're going to look at a range of slicer parameters so it's really important that you watch this whole video to get the most value and in addition we're going to talk about print geometry what are the finest features you can accurately print on a 3d printer and how does that impact stringy so stay tuned and let's learn something together [Music] as you can see from the number of models here and there were many more than I printed fine-tuning a profile is a lot of work but in fact to get a good profile that does very little stringing is not much work at all anymore this is the classical string test which has two towers that are about three millimeters in diameter and it prints perfectly on my printer using a default Kirra profile now what printer did I use well it started as an ender five earlier in its life and as you can see in this picture here it's now changed a lot so I added an all-metal hotend I added Capricorn Bowden tubes I added a new control board in essence it's a brand new printer it even has a new extruder that you'll see pictures of later so it has to be tuned like a new printer one of the things that's so very important is when you make a change you probably have to retune your profile a change could be a different brand of filament in some cases people claim that the characteristics of different colors of filament work differently change is clearly a new extruder a new hot end a new control board a new type of Bowden tube these are all changes that impact your printer so while my printer started as a creole tea under five and I love that the reality ender line of printers is so hackable today it's really a dr. VAX printer one of the challenges I had with this printer is that when printing very narrow towers at the top of prints there was a lot of stringing now this printer has a micro swiss hat it's an all-metal hotend and all-metal hotends give you the advantage of printing at much higher temperatures between the Capricorn Bowden 2b and the all-metal hot end instead of printing up to about 230 250 I can print up to about 280 plus degrees centigrade on this printer and I can do it safely but the standard profiles create a lot of stringing so let's dig in and learn about this to begin with we have to understand what is stringing what causes springy so let's look at a picture together this is a picture of the g-code preview mode or the simulation mode on simplify 3d now you'll see all of the red lines those are travel moves a travel mood is when your printer after it's done extruding filament needs to go somewhere else to extrude more filament but in between those two points let's say when it's printing this tower and then it moves to print this tower it doesn't want to extrude filament that's called a travel move now if there's a little bit of filament leaking out of your nozzle it's going to create a string if there's a lot of filament leaking out of your nozzle you know something that looks like this so each one of these red lines on this picture you're looking at has the potential for stringing now let's look at how these towers are going to be printed live in a live preview now you'll notice here and it's printing the inside and then the outside of each of these towers the order that you print walls or particular objects the outside of objects is important and will impact stringing let's think about it you're printing the inside then the outside and then your moving if instead you printed the outside and then the inside when you first go to move you're in essence dragging the nozzle over that outside wall that's actually called a wipe and that would reduce three so one of the things we could see from watching this video was perhaps we should change the order that we print the walls now the two prints you're gonna see now were in fact printed on different printers so this was a default profile on my ultimate to my monoprice ultimate - this was a default profile on my Ender 5 now the Ender 5 profile musing came from kira and the new profiles in kira are generally quite good because as I showed you earlier you can get really nice prints with no stringing if you don't have very fine features but if you look at these the top of this print it's ugly but this shows you what's possible now there are other differences here this is a Bowden tube setup this is a direct extruder by adding an all-metal hot end I increase the amount of stringing on this printer in exchange for higher temperatures so our challenge today is to go from this to this now the most important parameter that you may have to tune assuming you're using default profiles which as I said today are very good is temperature and a wonderful way and I'll link to this in the description is to print a temperature tower and we'll see a picture on the screen of this close-up and what you basically do is you go into your slicer I'm using Kira for all the examples here and you tell it at different layers to set different temperatures and then you look at the amount of stringing you can see the stringing better on the back of this and then you pick a temperature where there's a minimal amount of stringing what I found is I've been printing too hot I've been printing almost all PLA at 205 degrees centigrade because that's what worked best for me a year and a half two years ago on a Prusa i3 MK 3 I think it was about a year and a half ago and I found that that's the wrong temperature by looking in this tower I see that the stringing really stopped at about a hundred and ninety five degrees so the tests we're doing today you're at about 185 to 190 degrees in order to reduce three but even at that temperature I still saw a lot of stringing now before we look at the other parameters in cure specifically but the concepts apply to all slicers that impact stringing we need to understand the concept of a 3d printer and extruding filament and what happens when you extrude filament so let's look at this picture together there are really two basic types of printers or two types of setups for extruders in the more common setup at least for low end printers and the majority the printers I own are this type of setup you have an extruder which is either a set of gears or a gear in a wheel that pushes your filament through a tube this is called a Bowden tube Bowden tubes come in different quality the standard Bowden two's provided by it with many printers are good but not great what makes it great well the accuracy of the channel or hole on the bulb Bowden tube and how slippery the material is this is Capricorn tubing it's not expensive it's probably one of the least expensive easy upgrades to every Bowden style printer you own this is very slippery and very precisely manufactured now the extruder once again on the picture pushes the filament through the Bowden tube to the hot end on the right side we'll see a direct-drive extruder I own three direct drive printers that's my Prusa i3 MK 3 is direct drive my monoprice ultimate 2 is direct drive and my quitte printer is a direct drive and in general direct drive printers have the advantage that there's less play in the filament because it's going directly from the extruder to the hot end it doesn't need to travel over something that can wiggle wiggle and vibrate and many have clearances that are a bit too wide in the tubing that means the printer can more precisely control the extrusion of filament the disadvantage of a direct-drive extruder printer is you have all of this weight moving around which can increase vibration if the printer is not robust enough okay now let's look at some of the parameters that impact how the extruder interacts with your hot end and how it controls the flow of filament from your nozzle so you get just the right amount of filament out to have a proper print but not too much where it starts dripping or easing out of the nozzle which causes stringing the most common set of parameters that impacts tree are retraction and in most current slicers that is assumes that you've loaded the most current version so if you're on a two-year old version of Kirra you're not going to have built-in profiles that are excellent if you're on 4.6.1 the built-in ender profiles as an example the cree ality profiles are quite good and will give you very acceptable prints except in extreme circumstances so we're tuning for extreme circumstances so the first thing you have to look at is retraction that includes the amount of filament to retract now when you have this floppy tubing you have to extract more filament because there's actually a little bit of give in the tubing so you might be extracting you might be pulling back three four five six or seven millimeters of filament now there's a misconception when you're pulling back on the filament you're not pulling any filament out of the nozzle the filament nozzle is melted it's soft already you're not going to be able to pull it back what you're doing is reducing the pressure that you have on that nozzle by pulling back the filament you're reducing pressure that will reduce boozing and leakage from your nozzle the other parameters you change are the speed you pull it back at and the speed and amount that you push forward when you're going to print again now why does the prime parameter or the amount you're pushing forward have an impact on stringy because what you want is you want to keep just the right amount of soft melted filament or semi melted filament in that nozzle so that the filament in the nozzle will adhere to the filament that's coming out of the nozzle and you'll have a good connection there because if you pull too much back or you pull back too fast then you have soft filament in the nozzle there's nothing holding it at all maybe you've snapped off in essence the filament that was connected to it so you want to get the flow optimized by optimizing the amount of retraction the speed the amount of priming and the speed of priming now in a typical direct drive direct extruder model printer you'll often pull back 1 to 2 millimeters of filament in a Bowden tube printer you'll often pull back three to seven millimeters of filament the next thing in Kirra that will impact stringing is combing when you're printing you stop you're going to make a move if the area you're printing over is going to see another layer on top don't bother retracting because we don't care about strings that are inside now in fact if you have on your final layer on the top of your print if you're printing relatively thin walls you'll actually see those strings through the walls so you have the option to turn coming off to comb only in the fill area or to not comb on the outside of your model I recommend the Select not coming on the outside in earlier versions of cura this was not the default it is today once again slicers are getting better and better next we have an option called coasting what that basically says is instead of pushing filament out for the whole print length when you get towards the end of the area you're printing stop pushing because they'll already be enough filament there to continue out that's called coasting because I am having difficulty of this model and I noticed that on the bottom it's fine on the top as the towers get narrower it starts stringing I wanted to see what the size was that caused a stringing I created a model where we have three millimeter two millimeter and one millimeter towers and this is going to be printed in this direction so you can see anytime it goes from a 1 milliliter tower to another area they're stringing when the other area is closed the strings on end up connecting when they're not they end up sort of just floating around in space so what I found is that for my end or v with an all-metal hotend a post size of less than 2 millimeters will increase the amount of string in the model so if you're creating a model that's something to think about you perhaps want to keep features at about 2 millimeters or larger to reduce stringing now that we've covered a range of parameters the first thing you need to tune once again is temperature and that will get you to a print that looks like this with two and three millimeter towers you'll have prints that have almost no stringing on them but for many printers if you go below two millimeters such as the top of these towers you're going to have to do some more tuning in order to get it right now part of what you're attempting to do is control the flow of material because in these really nice prints this is in the ultimate two it's not only a lack of stringing and there's some very fine stringing here but you can barely see it and you could literally just snap it off with your fingers the tops of the towers are very precise these towers look really beautiful if you look at some of these these towers do not they look like they have a serious problem let's look at a video of what happens in very narrow towers when your printer is not tuned properly so we can see here we're going from the three millimeter to the two millimeter to the one millimeter tower and did you see that I'm the one millimeter tower the tower wished vibrating it was shaking so what that's saying to us first of all a one millimeter feature is very thin these ear savers that work with masks that I made for some buddies of mine knew or doctors are about a millimeter one point two millimeters you see they're very flexible so if you're printing this vertically this is gonna move around if even if you print it perfectly so we need to ensure that the flow of filament to these towers is perfect and that really takes me to the conclusion the way I went and this was printed with the newest profile from these terrible prints with the original profile where the tops weren't very good but they printed this model fine to this one where it's pretty darn good this is on the end or five it's not quite as good as the ultimate - still a little more work to do but it's pretty darn good was by thinking about the flow of filament so I want to keep that all-metal hot end full of filament but not too full if I pull too much out it will string more if I don't pull enough filament back to reduce the pressure enough it will string more if the timing the speed at which I push filament in and pull it back is not optimal the hot end and the nozzle won't be properly pressurized it will string more so let's look a look at the profile I ended up with now I will provide this profile on dr. VAX forum comm there'll be a link in the notes and you do need to know that this will only work in 4.6 of Keira so if you're not on the current version importing this profile may not work but I'll also leave you a link to these slides and you'll see on this slide all the parameters that were impacted as we look at these optimal parameters there's a bit of background that's important number one I'm using Keira 4.6.1 I installed the default under-five printer setup and I started with the default under 5.20 PLA profile I then edited it to make these changes these changes are our combination of experimentation lots of models and things I learned from looking at the monoprice ultimate - profile that produces really very beautiful prints now the monoprice ultimate - is a direct extruder printer so the retraction settings were not applicable but some of the other settings were interesting the reason I believe they have an impact is there are many parameters in Keira that have a subtle effect on the printing of small items the order of the printing of walls the impact of very small features on your model so I brought some of those capabilities over along with the experimental capabilities let's get started filter out tiny gaps is set to on or true now when you have an internal small space in your model perhaps the very top of one of these towers this informs Keira that it shouldn't try to fill in that space that reduces in less blobbing or artifacts on your print material flow at 95 that's 95 percent and that will slightly under extrude this print the print temperature was set via experimentation with the print tower optimized optimize wall printing order equals false this was a setting from the ultimate 2 profile I haven't experimented enough with this particular setting to see if it has a significant impact but I brought it over from the ultimate to the retraction amount the retraction speed the retraction prime speed or all settings that were developed both through experimentation and by reading lots and lots of online discussions about retraction and as you can see it very definitely worked because I was able to get really clean prints with these settings skin overlap the very outer layer is considered skin by Keira and the inner layers of a wall before it hits the infill our considered wall the overlap between that very outer layer and the inner layer here set it 5% that impacts the quality of your skin this could have an impact once again on the towers read speed of 75 the defaults and the profile was 80 this is a minor change travel speed the idea here is to travel very quickly when you go to travel to sort of snap off those strings so they can deform travel retract before outer wall this may be a buggy feature in Keira and may cause the printer to attempt to retract before inner walls also and so I left this off and with it off the quality was quite good once again more experimentation is necessary the rest of the parameters here probably do not impact stringy they are parameters I did bring over from the ultimate two and they may impact overall print quality so that takes us to the end of today's presentation folks I hope you learned a lot I hope you'll share this information with other people that might be interested in learning this subscribe to the channel and there's a new way that you can share in the discussion with other people watching this material and that's forum that dr. VAX dot-com it's a new discussion forum it's based on vBulletin it's free to use you do have to register if you want to post that means just providing your email address so that there's a way to potentially block people that are doing things they shouldn't be doing on the forum and so there are a number of ways now to interact with the dr. VAX community thanks for watching have a great day let's continue learning things together

Channel: Make With Tech (MakeWithTech)

Views: 130,080

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Id: WLWYzJe8zxI

Length: 24min 15sec (1455 seconds)

Published: Fri May 22 2020