How to STOP Elephant's Foot on your 3D Prints

lately i've been 3d printing a lot of parts that have to accurately fit together in complex mechanisms sometimes even printed at the same time and they have to move independently when the print's complete and i've been struck by the dreaded elephant's foot and i thought look i haven't really talked about this effect here on macy's views and how i mitigate it with design tweaks slicer tweaks and most importantly setting up your 3d printer properly for that first layer so if 3d printing things accurately is important to you and you want to get top score on the clearance gauge watch on [Music] how's it going guys angus here from makersviews and welcome to a 3d printing 101 i haven't done one of these for quite some time this is a topic that i really figured i haven't done a dedicated video on because it really is important and something that's often overlooked but before i talk about how to mitigate it i need to explain what the elephant's foot artifact in 3d printing actually is and this can apply to fdm filament-based 3d printers or resin-based 3d printers as well they both can suffer this effect and this is how it happens so the first layer with your 3d print is the most important layer by far if it's too far away the print will not stick it'll come off the print bed and and fail horribly and too close nozzle will dig into the print bed and it'll cause all sorts of damage but often the advice is to make that first layer just a little bit closer than normal so the prints will stick reliably and slicers often even have settings to make this first layer extremely aggressive maybe the flow or the width of the extrusion is increased maybe the speed's decreased and the layout height may even be decreased further from the rest of the prince layer height to make sure it's really stuck down well and that will work really well to keep your print stuck down but it does have some downsides and the main downside is the elephant foot effect and what happens is the 3d printer will extrude too much plastic for that first layer but that material that molten plastic has to go somewhere so it will start squishing out and because you constrain the z height it only has the x and y axes to squish out and this x y expansion can continue quite a fair way up the 3d print until everything normalizes and averages out and the part becomes accurate to the correct extrusion width you actually intended for a 3d printer where the first layer height is extremely close to the bed this elephant's foot effect can be very very obvious but for some printers it can be really hard to see and almost completely remove but it generally exists there's always just a little bit of extra material in the xy axis for those first few layers and it's that extra material that stuffs up these models this is my clearance and tolerance test gauge that i designed quite a few years ago now but it's still one of my most popular models and it has clearance gaps of 0.5 all the way down to 0.15 and that's gap gaps between each wall so the 0.5 has in theory one millimeter of total movement it's 0.5 between each surface and by far the biggest issue people have when they print this is the first layers weld together because of that xy expansion that elephant's foot effect so when you print it even though the top surfaces or the edges might look okay the bottom is just one solid sheet of plastic and you've got no chance of separating the model so how can we mitigate this well the first place to start would be your 3d printer to try to dial that first layer accuracy in as well as possible so here's a common misconception with 3d printers when you home the machine it will move to 0 0 0. that's the start of the coordinate system points so it'll go from there in the x y and z axes and when you're setting your first layer height currently people advise to use a piece of paper and then get your nozzle home the machine and then move a bed up or move the nozzle down until it's tightly gripping that paper but by doing this you're not actually setting where the nozzle will start printing because the machine will see this as zero the machine will not try to print at zero it'll start printing at your first set layer height which may be 0.15 millimeters or so so often what i see is people use the piece of paper they're very tentative setting it so it's barely touching the paper and then the machine will then go to set that first layer height it'll be even further away than they expect and the prints will not stick so the next thing they do is they wind everything super close and they make that paper really dig into the nozzle between the print bed and the nozzle and then they go the opposite direction the prints are stuck down sure but the nozzle is way too close for that first layer we're dealing with tiny measurements here so you don't have to be too pedantic but just keep that in mind when you're setting your nozzle height i just use a piece of paper myself but i make sure it's usually quite tight and i will watch that first layer to ensure it's level around the print bed so for models like this where there's parts that have to slide in with each other the first trick i'm going to advise is to use underside chamfers in your modeling software so let me show you how that works so what i have here is a headphone holder model i recently showed on the channel and i've done a lot of tweaks to this model to make it easily printable and to mitigate that elephant's foot effect i did actually mention that video uh in the final print and i've done that using a very small chamfer here so you see on the other side of this model it has a very slight chamfer and it is very small so small in fact that it will probably be cancelled out by the elephant's full effect and it will just look like it's a straight edge when you print it and every print is going to be different you might have to figure out what what measurement works best for you but for me i'll go as small as 0.5 up to about 0.1 millimeters in terms of that chamfer it really is tiny and there's a 45 degree angle so if you're concerned about it printing as an overhang again it doesn't matter what you'll find is that first layer expands it'll be compensated for by the smaller cross section and then as the print continues it'll average out and then you'll actually very much mitigate that elephant effect for your 3d print now for this one i do have this little edge here which is done to support the back of the model because i also hate using support material and i haven't done that here because you need at least some contact area for parts to stick properly to a print bed i find if you're going to do that chamfer here you'd have like just one line or two lines of contact in terms of an extrusion with filament-based machines and that's just not enough to ensure connection to the print bed so i didn't do it on that part and it's very obvious in the final print to see that that part the elephant's foot effect is very pronounced i even did the underside chamfers to the holes because i find the elephant's foot especially in holes can completely block them up and it's just a good way to save a bit of time you don't have to go in with a drill and clean out those holes by doing the shaft from the other side of them it means that they'll be a little bit more accurate when you do your 3d print in this example i have a very complex model it's a print in place puzzle i've been working on and just to show you a cross section it's got a lot of stuff going on but i needed to print uh together and not weld together on the print beds so let me show you how i've done it i've employed chamfers but i've also employed generous clearances and again the clearance intolerance gauge is designed to help you figure out what your machine requires that you can then take those numbers and then use them in your cad software to inform your designs like i mentioned with the headphone holder and that support i didn't want to reduce that so much that didn't have any contact area and similarly with this this out of ring i didn't want to make too small with two bits of two chamfers uh really reducing that cross section so instead i've done a chamfer on the outside part here that's more or just aesthetics because there's nothing interacted with there i've done just one chamfer on the inside part so these are two separate parts two separate bodies and by doing that chamfer there it means the parts won't expand due to that elephant's foot effect and weld together because if this puzzle welds together on the first layer or two then it's going to ruin the whole experience and i've even got a chamfer here for this part here and then for clearances because this model is so darn complicated i went with a 0.6 millimeter clearance because there's just so much going on here they wanted to make sure that the parts were really far away and they didn't weld at any point so that model's coming in quite a while i've still got a lot of tweaks and testing to do but the first test actually worked quite well the parts go together like so and they did actually print in one go on the up mini 2 for this case so that's pretty cool and that's one way you can also mitigate your elephant's foot effect but let's say you've already got the 3d printing model you've got the stl you don't have access to the cad files to modify it what can you do to try to improve the first layer accuracy of your 3d print what i have here is a slice of that puzzle model but this slice doesn't have the underside chamfers to compensate for the elephant's foot effect so if i slice this and then show you what the cross section looks for the first layer these are very close together and if that first layer squishes out too much they're going to weld together and this puzzle is completely screwed if it welds together at the bottom so how do you mitigate this well luckily it's actually a well documented issue and most slicers now have a setting to let you compensate for this elephant's foot effect and in prusa slicer it's called elephant foot compensation how about that so to find it you go to print settings and then you need to make sure you have at least intermediate mode ticked where you can see these little yellow icons and then under advanced you want to go down to elephant foot compensation and then a positive number here will reduce the cross-section of that first layer so for example i'm going to do 0.3 uh millimeters and that will reduce the cross-section of the first layer by 0.3 like it's like an offset and now you can very clearly see that offset in effect so the first layer they the lines are quite far apart and then second layer they build in by quite a bit by that 0.3 millimeter uh setting that we chose now this has saved me many times in the past absolutely but there is one issue with this and it's just the first layer you can see it here the first layer is offset but the second third and so forth are just normal that might be okay for you but for some printers i find that that elephant's foot effect can actually be quite high up before it's completely gone and you need more than just that first layer offset you sort of need you need like the chamfer you need like a gradual transition between that first layer and a little bit higher up so the compensation at least in pressure slicer is just for the first layer it's worth knowing about but sometimes it might not be enough but there's one key issue that none of these tweaks will fix and sometimes it's really important and that's the overall height of your model say you want to print a 20 millimeter cube that's 20 millimeters high and you put on a 3d printer i i give you a challenge go try it and measure it it won't be 20 millimeters it'll be like 19.8 or something a little bit less maybe just a little bit less but unless your 3d printer is absolutely perfectly dialed in that first layer will be squished a bit which means the zed height overall the print will be reduced so sometimes you just need a perfect model and you need to use a raft i know people hate rafts i totally get it if you don't know what a raft is it's a sacrificial layer of plastic underneath your model that then you peel away afterwards and break away in fact rafts are so unpopular now with 3d printers that most people don't even know where to look to actually turn them on so just in case you don't know improves the slicer it treats raf sort of like a part of the support material so you go to print settings and you go to support material and then you can set how many raft layers you want there's no like just tick box for printer raft it sort of just offsets the model and then prints underneath it with support so let's just change this to two layers so you can see here the part is now built on two layers of material that is sacrificial and the part builds up on top of that it's the job of these two layers to kind of take up that inaccuracy that extra bit of squish so when the parts built it's built with the perfect uh z height but keep in mind we're still printing in layers so it'll be like a discrete uh multiplication of your layer height like 0.2 or 0.15 millimeters i'm printing this really cool four-digit combination lock at the moment and it's got these little gear selector parts inside and unfortunately the elephant foot effect even with mitigation meant they weren't accurate enough and the parts actually bind up and the the components don't work as well as they should in this mechanism so i actually have resorted to printing them on a raft and this is off the up mini too so i just left them on the raft to show you what it looks like don't look don't be scared of using a raft if you need it it means the parts will be more accurate it improves bed adhesion and yes it does take longer it uses a little bit more material that unfortunately is wasted you have to throw it away but it really can make a difference for getting parts just a little bit more accurate because at the end of the day that's why i have 3d printers i make them do my bidding to 3d print my designs my mechanisms my models and i will use every trick in the book to make these printers print as accurately as possible so my models actually work so thank you for watching guys hope you found this video useful on makers music my aim to empower your creativity through technology i look forward to unveiling all of these prints that i'm working on to you very soon especially this one um i can't even begin to describe how ridiculously complex this is uh maybe the first puzzle of design that is almost unsolvable i'm trying to make it a little bit easier so if you found this video interesting and useful and you'd like to see this puzzle and others on the channel then maybe consider subscribing and i look forward to seeing you again very shortly catch lady guys bye

Channel: Maker's Muse

Views: 216,977

Rating: 4.94066 out of 5

Keywords: 3d, printing, elephants foot, maker's muse, makersmuse, angus deveson, australia, 3d printing tips, 3dp tips

Id: zlgR3rHg4p8

Length: 13min 55sec (835 seconds)

Published: Thu Sep 03 2020

Reddit Comments

[u/jrJ0hn]

+1 for raft advocacy.