How to 3D Print bores without supports (Fusion 360 Masterclass)

recently I talked about this awesome trick I learned of prusa research parts for supporting Holes without using support material but I didn't really explain how to do it in CAD so I thought I'd revisit that idea with that concept as well as several other ways you can use to support your part without using support material using Fusion 360. let's get started [Music] from Maker's Muse and a big shout out to my community members over on the makers Muse Community if you're interested in joining for just five bucks a month you can get access to content like this a week earlier than anyone else as well as behind the scenes content and ask your 3D printing questions over in the troubleshooting Forum you can find more information in the video description below support material sucks we all know that but avoiding it could be quite difficult and over the years I've come across various different ways of Designing parts to avoid support material and the classic case of trying to avoid support material is this you have a bore with a hex nut or some sort of detail underneath it and you need that to print now yes everyone in the comments will say well just flip the orientation print it like that that would be the number one thing to do it's the first thing I try is to try to flip the orientation of a part to make it print without any support material because each layer before it will support the layer after it and you can't 3D print over thin air well kind of but you can't easily support this bore if it's printed like this without support material but there's different ways we can change our geometry to make this work and I thought in this video I'd do a deep dive into how I model these geometries to make my parts work without support material because in some cases yeah you will have to print like this so suspended disbelief don't type in the comments well you should just flip it let's just pretend for a moment this part must print in this orientation how can we make it work without support material well the first thing you do is just send it let's just print it with heart support material and see what happens this is the result and it's pretty much what's expected the first few layers failed they had nothing to adhere to and so sort of made this little bit of a Rat's Nest underneath the bore but I'll be honest with a bit of force you can get the screw in and it does eventually recover and you can get the nut into it as well so yeah it's not elegant but in very very small cases like this is an M6 nut you could just print it without support but it's not the best option so what's the second easiest way to print a detail like this without support material well if you watch any of my previous content at all you'd know that it's sacrificial bridging bridging is a phenomenon where you can Bridge a string of molten plastic between two points over thin air and then from there fill in like a platform that can support the part above it but there's nothing underneath it but for a bridge to work it must go between two points in a straight line it can't curve in thin air it's not going to work so sacrificial bridging takes advantage of that concept by doing a very very thin solid layer maybe like 0.4 millimeters thick and then bridging across a gap that it otherwise failed so in this case all I've done is with my detail I've drawn a sketch in that area where the hex would start to form the ball and in Fusion you just hit P to project lines and all I've done is I've projected the edge edge of that bore like so and then you select that detail and then you do an extrude of a very small multiple of the layer height you intend to go with so 0.4 is two layers of 0.2 and I find it's a good thickness for a sacrificial Bridge that's fairly strong but one you can bust away afterwards and I'll say okay make sure it's going the right direction and then join and just like that that part is modified so you can print with that support material I have used sacrificial bridges for years and I talk about them in my eBook The Ultimate Guide to 3D printing tips and tricks and they work really really well but they do have one serious downside they need to be busted through to make the ball work so sometimes you can just force the screw through like if it's like a small screw or it's just a really really thin bridge but often you need to use like a drill or a scalpel or something to cut it away carefully which leaves a raggedy Edge and is another Machining step that needs to be done after the print's complete so it can be a little inconvenient especially if you have hundreds of parts that now must have that hole busted through using a drill or something similar which is where these next tricks come in because they leave a open Ball but no support material is required this next trick takes advantage of the 45 degree overhang rule with 3D printing and that trick is where you can overstep the previous layer by a certain amount without the part failing and the amount you can do that depends on your layer height and your Extrusion width and your cooling etc etc but generally 45 degrees from the vertical is a good safe number for an overhang that works in most applications and it's one I tend to design as my models so if I'm trying to avoid support material I'll go from a detail to a 45 and then back to another detail and that 45 will allow the previous layer to support the next one and you can do that with our hex here so to add this 45 degree detail all I've done is I've selected the profile for the hex and then I've done a taper angle of -45 degree series which forms it into this sort of diamond Point here like so and that leaves us with a clean bore that will print without support material but we still have that hex detail and this simple change Works incredibly well we have a very very clear bore with no filament or wispy bits or failed print that lets us just insert that nut and screw in that screw now there is an obvious issue with this 45 degree however and that is if you try to tension this bolt too much you've essentially created a wedge in the part those 45 degree angles there's there's nothing there to avoid and that nut is going to be trying to force into it and just explode the part in the process so I'd only really recommend doing this the things that have a light loading or if you happen to have a nut that has that sort of conical shape to it that would actually snugly fit into this but otherwise it's really only a detail we're doing to make the ball easy to print and it's not the best solution in the world but it is very very easy to do but if we're looking for the best solution possible well then we have to go to that detail that I found in the pressure research prints and that is using sequential bridging visually this part looks very very similar to all of the others unless you look inside it and then you see this Trixie detail here which I like to call sequential bridging that's the detail I first came across on the parts from future research now I don't know if they invented it but it's where I first saw it and it's incredibly clever so what this is doing is instead of our sacrificial bridge going across in just one layer it's doing two sets of bridges to let us have a smooth open bore instead so as you can see here we've got this first bridge that occurs and then after that it does a second bridge and then it does the ball now the ball still has some curved edges overhanging you can take it one step further I've done three layers of sequential Bridges here where it's like one two three but I've found with at least small balls like with this M6 nut two is totally fine and any bit of filament that is overhanging in those small areas that aren't supported is really negligible but for much larger Bridges you might want to try doing three or even more to fill up those layers to support the overhang part but just stepping back to the two layers of sequential bridging I want to show you how I drew this using one sketch now bear with me this is Advanced CAD knowledge using Fusion 360. but if you can understand this it will Turbo Charge your 3D modeling capability in the software so let me step back and show you the sketch I did to start everything off so here we have the original sketch and this sketch is used to draw the entire part and we're doing that because each different extrude is done based on an object's surface starting point instead of the original sketch plane point and I'll show you how that works in a second but we have the hex here for the m6 we have the bolt hole for the six millimeter bolt and then we have the outside of the part like that and finally we have our sequential Bridges so we have the first Bridge like this and this area will be supported by that bridge as it forms and then the next Bridge after that would be this one here and then finally it's going to form just these little edges there which again this small enough that they don't really need support at least at this scale and the part forms like that so how do I construct this model using multiple extrudes with the same sketch we start with the hex offset and that's just done from the profile plane but then we have the bore offset and I've done that from the object start which is the surface of the previous extrude so to show how that works if it was from the profile plane it just be from the sketch up but by selecting from the object I can select the surface of that previous extrude and then it's going to extrude its own amount by 2.5 millimeters here so you can see that no matter how much I change that previous extrude I can make it like 100 millimeters deep it'll still start from the surface of it which is really really powerful for parametric modeling and what how I like to do the sequential bridging is to add it at the end because I see it as a detail you add purely for 3D printing so I add it after doing the original modeling and because of that I do it backwards so bear with me it's a little bit confusing but we're going to do two extrudes and each one will start from the inside surface here of that bore so we're going to start with the second bridge and then go back to the first bridge and then that's done and it looks like this the first detail is done here on that ball and that's what the second bridge looks like right I've selected just the profiles for that extrude and the starting point is that surface that I need for that detail and then stepping back one more time that's the first bridge that occurs and I've selected just those profiles so just to show you in this case the profile selected uh these ones like so and this Ball's got a little bit of overhang there so make sure I select that too and again the object or the starting point is that surface that I want to extrude from so from the previous one it's very difficult to explain and I wish I could do it better but I will share these files over on the makeup music community at the bottom of this uh video post so you guys can have a play with it and figure out how you how you want to form it you could go the other way around if you wanted to you could start with your hex and then do your first Bridge second bridge and then bore that might make more visual sense to you but I tend to do it as an afterthought once I've modeled my parts and I realize oh that hole needs support how am I going to do it so that's this is generally how I do it for my real world models then finally we have that little chamfer which again we're printing like this on the print bed and that just gives you a little bit of extra wiggle room to avoid elephant's foot and uh especially when you're putting like a nut into a surface you want to avoid that at all costs so it's not a nice snug fit that any dimensional deviation and that is the many ways you can support overhung holes with fdm 3D printing without needing support material it's very technical but this is how you absolutely level up your 3D modeling skills because by avoiding support material you avoid the need for any sort of post-processing of your model and also you make it so that the parts always going to print you have to worry about someone printing your model and then oh they didn't use the right support settings or oh their printer welds support into place they can't remove it from a ball by taking these techniques into your own designs you can make them more successful more often for more people and that's my aim here on Maker's views to empower your creativity through technology and it's these little details that just keep an eye out next time you're 3D printing someone else's cool design to see what else you can learn from what they use to make their models easier to print and let me know in the comments below or here on makers videos in the community the the thread below this this video how you make your models easier to print using little design tweaks and changes because yeah again I'm learning all the time I only figured out this pressure research trick recently I've I've been doing sacrificial supports for years and doing like like 45 degree overhangs for years but this this sequential bridging thing it's definitely an eye-opener for me I'm going to be using it pushing forwards to make my designs even more fancy and is even easier to use so thanks for watching guys hope you enjoyed this video here on Maker's Muse and I'll catch you again very shortly bye

Channel: Maker's Muse

Views: 316,877

Keywords: 3d, printing

Id: KBuWcT8XkhA

Length: 13min 12sec (792 seconds)

Published: Sat May 20 2023