How To Get The PERFECT First Layer on Your 3D Prints

getting a smooth consistent first layer of plastic to stick to your print bed is one of the key aspects of fdm 3d printing understanding the fundamentals of how this works is key to getting consistent prints there's a lot of confusion and misunderstanding out there about this so allow me to attempt to demystify it for you [Music] i break down the first layer into four fundamentals number one is bed adhesion number two bed level number three z or nozzle offset and number four is slicer settings and i throw in a number five bonus we'll talk a little bit about part geometry bed adhesion is how well the plastic sticks to your print bed we need the plastic to stick to the bed to well hold it in place while it's printing but also to counteract the contraction of the molten plastic as it cools there are many combinations of print bed materials available i have experience with two so i'll share those with you but just know this is far from a comprehensive list and you may find something that works better for you a glass bed with hairspray this was my go-to standard on my cr-10 for years and it works great with pla and petg and don't just go spraying it all over the place all over your printer that can cause gunky build up which will look ugly but could also potentially interfere with the mechanical connections of your printer instead use something like a cardboard box to make yourself a little mask so that all the overspray will stay on the bed where you want it pei coated spring steel sheets pei is a special high temperature plastic that for whatever reason sticks really well to other plastics when they're hot you can coat just about any flat surface with pei and it will work fine but some smart person somewhere decided it would be a good idea to coat a thin piece of spring steel like this with pei so that you can just magnetically attach it to your printer and pop it out and flex it to knock the parts off it works great it's super awesome and i would recommend this as an upgrade to anybody who maybe doesn't already have it on their printer pei sticks great to pla and abs and by extension it should also work great with asa uh for whatever reason i tend to have problems with asa it's not quite as good as abs it still works but it's not quite as good so maybe i have something else going on here and your mileage may vary pei sticks too good to petg do not use petg with a pla sheet the pecg will bond to it and you'll destroy the pei when you go to remove the part as a workaround you can just coat your pei sheet with hairspray just like the glass bed and that works great the petg will stick to the hairspray and the hairspray will protect the pei coating on your bed and then to remove it you just flex the sheet like you normally would and to wash it off you just use warm water hairspray washes right off i can also get polycarbonate to stick with pei as long as i'm using magigoo's special pc blend formula as an adhesive that stuff goes on just like a glue stick and when you're done it washes off with warm water just like hairspray so you can convert back to printing pla or abs pei works great but it does have a limit and that it will wear out with time you'll kind of just notice one day your parts just stop sticking when that inevitably happens there are some things you can try first clean the pei sheet with 91 isopropyl rubbing alcohol if that doesn't quite do it the next step is to sand or resurface the the pei with a fine grit sandpaper like 600 then clean it with alcohol again try again you can also try cleaning the pei sheet with acetone i've read that that's supposed to work but i've had mixed results with that so your mileage may vary i would stick to cleaning with alcohol and sanding and then cleaning with alcohol if all else fails you might need to just replace the pei sheet they're not that expensive but i have found that i've been able to basically extend the life of these sheets indefinitely by just standing the surface down with 600 grit sandpaper and cleaning with alcohol symptoms of poor bed adhesion the material just never sticks at all it'll just kind of gum up around the nozzle and make a mess [Applause] [Music] the material sticks in one area of the print bed but not in another this is a common symptom i've seen with pei sheets that are kind of starting to wear out and it's a sign that you need to stop your print and clean or resurface the sheet parts of the first layer start to peel up especially noticeable in sharp 90 degree corners or in areas of the brim if you're using a brim or the part just comes loose during printing bed level bed level means that your bed print surface at all points along the surface of the bed are orthogonal to your z-axis or nozzle of your printer in other words the imaginary plane that the x and y axes draw out is parallel to the bed first thing i want you to do is ditch the bl touch or other bed leveling sensor i see way too many posts in various forms of new users having trouble with this either technical or just not understanding what it's supposed to do for now we'll keep things simple and you can add complexity later but it's important to understand how to properly set your printer up mechanically first before adding software solutions like a leveling sensor my preferred method for leveling the bed is the so-called paper trick where you slide a piece of paper between the bed and the nozzle at several different points there are many guides online on how to do this so i won't go into detail here but i will just add that the thickness of the paper that you use or the how tight the paper fits between the bed and the nozzle is not important all that's important is that it's consistent at all points along the bed i like to aim for the paper grabbing to where it's just tight so that the paper can't really move not so tight that it's totally clamping the piece of paper you can drag it out if you if you really try but not so loose that it's easy to move around again the key is however tight you get it or however thick the paper is just make sure you're consistent along all points across the bed and that is a good segue into the next fundamental which is your z offset z or nozzle offset is the distance from the nozzle to the print bed and it's oftentimes lumped in with and glossed over with bed leveling it's critical to understand and approach configuring these two functions independently that's why the thickness of the feeler gauge that you use in your bed leveling step is not really important with bed leveling we're just trying to get the bed level then we adjust the z or nozzle offset as a global function one then the other not both of them together with your bed level set mechanically then you can set your z offset in either your slicer settings or your printer's configuration menu it's typical to see this value change sometimes as often as every print i always watch the first layer of my prints go down and i adjust the z offset in real time to get that right amount of squish usually in increments of 0.5 to 0.1 millimeters on my ender 6 i can use the touch screen functions for that and on my voron v0 which is headless i use some custom buttons that i set up in the octoprint web interface but how do you know what is the right first layer squish well it kind of comes from experience and having a good eye it'll vary a little bit depending on material selection and your print height the ideal squish can be somewhat tricky and subjective but here are a few examples of what to look for here the nozzle is way too close it's just dragging along the print bed and there's no room for plastic to be extruded out this is a potentially damaging situation you'll want to stop it right away because you can grind away the tip of your nozzle or score your print bed you'll also likely hear your extruder making a skipping noise as there's nowhere for plastic to flow and the gears just are slipping on the filament [Applause] this can cause extruder and nozzle jams and can gum up your extruder with the little bits of shaving plastic so again you definitely want to stop this right away in the next example we can see filament coming out but your z offset is still way too close the cross-sectional shape of the extruded filament will have a very flat top and the line of filament extruded will be much wider than the nozzle as there's nowhere for the molten plastic to go but out the sides this will cause rather distinctive patterns if you're using a skirt or a brim or just a lot of perimeter lines in the first layer you'll notice the material start to get along the edges it'll start to get rough and jaggedy and that's because again there's nowhere for the plastic to flow but out so it just kind of builds up along the edge it will also cause a particular sort of striped like tiger stripe type pattern in a long and a large flat first layer because again there's nowhere for the filament to go so it just warps up you might be able to get away with a print doing this but it's far from ideal this example is looking just about right not too much squish but a little looking closely at the cross-sectional shape of the extruded filament the top will still have somewhat of a flat appearance and the sides will be squished down but not nearly as much as in the first example now we've got the z offset too high the cross-sectional shape of the extruded filament will be just about circular and you will not notice squish down at the sides the material might not stick in the corners and arc moves curved shapes will likely end up as straight lines individual perimeters or the brim will not be touching again you might be able to get away with printing like this but you're much more likely to have a print failure due to the part coming off the bed because it's not properly stuck down now here the nozzle is set way too high and notice that it looks similar to when you have zero bed adhesion because well if there's nowhere for the the plastic can't stick it just spits out and so again you'll have it end up winding around the nozzle and just making a mess of things slicer settings this mostly just comes down to making sure that you're printing at the temperatures recommended by the filament manufacturer i usually like to print at least one perimeter of a skirt to check the z height as it's printing and also to you know make sure the nozzle is primed before actually starting on the part you'll want to use a brim for materials like abs asa petg and polycarbonate basically any material that's more prone to warping and sometimes i'll use a brim with pla if i need a little bit extra surface area for good adhesion i usually go with a five millimeter brim anything more i think is just kind of waste of the time and material you might also set your first layer height to be a tad thicker than your other layers so if you're printing at 0.2 millimeters your first layer is maybe 0.25 millimeters that extra little bit of material can maybe kind of help things stick down a little bit and of course you probably will want to slow down your first layer both to help with adhesion and also so you can watch it print and make sure that everything is sticking nicely and one other thing you can tweak if you're having trouble most slicers will let you set a different temperature for the first layer for both the filament and the beds so maybe you want to print a little bit warmer on that first layer just to make sure things are getting stuck down all of these settings of course will vary between filament filament manufacturer printer and bed selection so you'll need to experiment to find out what works best for you and you'll probably need to re-experiment every time you change one of those things when in doubt start with the middle of the range of temperatures that the manufacturer of the filament recommends and finally a note about part geometry when designing parts for fdm 3d printing you want to keep the first layer in mind you'll want as much surface area as possible given your part geometry to ensure good first layer adhesion for example with the parts i designed for the 3d printed carbon fiber bike frame i oriented the parts and added material in such a way that i would have a nice flat surface for the first layer this isn't particularly cosmetically pleasing or an optimal use of material structurally but we have to keep in mind the limitations of the manufacturing technique that we're using having good first layer adhesion is key to having a successful print particularly in large parts like this that are made out of materials that are prone to warping also consider the mechanical forces involved while you're printing if you have diagonally shaped parts where you have large overhanging areas as you print the center of gravity will move outwards thus inducing a torque on your part which could pop it off the bed one example of a tricky part like this was the ribs for the 3d printed t-rex skeleton that i built those parts were very thin long and skinny and they were quite tricky to get to print right well there you have it my four fundamentals of first layer fdm 3d printing bed adhesion bed level z offset and slicer settings but what am i missing am i leaving something out let me know down in the comments maybe you guys have some ideas or some techniques that work great for you that i'm missing out on here also of course help me out with a like comment share subscribe all that stuff and i'll check you guys out on the next one [Music] you

Channel: Dave Aldrich

Views: 48,674

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Id: mXjTYDg-KNs

Length: 15min 7sec (907 seconds)

Published: Sun Oct 31 2021