Spur Gears in FreeCAD

all right welcome back to another video and today i'm going to show you how you can create simple gears in free cad i recently made a similar video on how to do this in fusion 360. i received a few comments on how to do the same thing in freecad first thing i'll say is that freecad doesn't have as many advanced tools as you get in fusion 360. so you are a lot more limited in terms of what you can do if for example you're looking to design a helical gear or a worm drive gear that's going to be a lot more tricky and is likely going to require some other tutorial that being said i'm always looking to learn and if i do figure that out i will make a video about it so let's jump into it and i'll show you some basic gears so we're in freecad here and as always the first thing we do when we're creating something new is we create a new part and we make it active so we're going to click on this little button here that gives us a new part and straight away i'm going to rename it so i'm going to right click rename i'm going to call that gear one now as soon as we create a new part we always create a new body so let's go up to the workbench tool we're going to switch to the part design workbench switch back to our model tab make sure you've got your gear one part selected and then click on this little blue icon that says create a new body and make it active that now gives us a body that we can manipulate and create 3d objects out of so with the body selected we're going to come up to part design and right at the bottom we've got an option here called involute gear click on that that'll take us to a new window like this and you'll see in front of you basically what looks like a gear but you haven't had to sketch anything and it's basically already a template there for us this is really useful because generally gears or spur gears are always going to follow the same pattern and you just want to tweak a few parameters so it saves you having to redesign these things over and over so on the left here we've got a few parameters you can see we've got a number of teeth module pressure angle and a couple of other options in there as well now these parameters are always going to come down to personal preference but i'll give you a rough overview of what they are and how you can use them the first one is pretty obvious number of teeth that obviously defines how many teeth are around the outside of your gear so module you can actually get pretty technical on what exactly module is but all you basically need to know is that module will define how big or small your gear is essentially going to be really large gears tend to have a higher module and tiny gears have a smaller module pressure angle again you can play around with this if you get technical but generally when you're working with 3d printed gears you're always going to leave this at 20 degrees because after a while anyway plastic gears tend to wear away and it becomes kind of irrelevant as general advice i'd leave it at 20 degrees high precision that's an obvious one we're just going to leave that at true and external gear what this basically is asking you is are you meshing with gears that are going to be on the outside of this gear if we change external gear to false you'll see that the shape of our gear slightly changes and with this particular shape what we could do is create internal gearing so let's say we wanted to create gears that are smaller than this one and have them all mesh with each other inside this gear that's what we'd use in this case we're not doing that we're going to leave it as true because we're meshing with gears they're going to be external to this gear so let's put some of these parameters in and actually create something for this i'm going to create number of teeth i'm just going to put it as 36 and module we are currently set to 2.5 now let's say for example we're working on a project and we need a gear that is going to be 50 millimeters in diameter now this is where you'll see that module is merely a ratio between the diameter and the number of teeth that we've got going back to our example if we change this and we need a 50 millimeter gear 50 millimeter diameter all we do is divide that by the number of teeth so 50 divided by 36 we'll just click away from it and you can see our module is 1.39 and that's all there is to it pressure angle as i said we're going to leave that and we're going to leave these set to true now we're just going to hit ok and notice nothing really changed there and that's because we have to go about this like we normally would with the sketch so we're going to select body and up here on the menu remember we need to pad so that we can take this sketch from the 2d workspace into the 3d workspace pad a selected sketch make sure you've got body selected and you can see that has now extruded that for us i'm just going to leave this at 10 millimeters and if you rotate around you can see now we've got something that kind of does resemble a gear so in this case you can set your width depending on what you need and then you can just hit ok so next i'm going to show you is how you can add a hole to the gear so that maybe you could place it on a shaft so if you remember in the previous tutorials what i showed you was how you can just keep using sketching to make changes to your 3d object now that's one way to do it and in freecad you can just stick to the 3d workspace if you're just looking to kind of create a rapid prototype or a really quick design you don't have to always go through that sketching process now it's always good practice too 99 the time i do stick with sketching just because it's more defined and you have more control over what's going on but just as an example i'll show you if we change to the part workbench so up here we're going to change the part now let's say i want to add a hole to this up here there's a little button called create a cylinder so make sure you've selected your gear and we're going to create a cylinder so that cylinder has been created for us and if you look on the part 3 you'll notice that it's placed it outside of our active part and this is a little bit frustrating it's something i've noticed about free card by default it just seems to put your other shapes outside of the part which just doesn't make sense and it's really untidy so what you want to do is click on the cylinder drag it over to gear one and you'll see that i'll just place it inside of your part here so if you minimize it it keeps everything nice and tidy by having it nested inside of that part it should do this by default but for some reason it doesn't if we click on cylinder down the bottom we've got a couple of parameters the radius here is set to two i'm going to change that to five hit enter and you can see it's changed the diameter there of the cylinder now here's the cool part we can actually create a cut between two shapes so if we select the body first and then hold ctrl on the keyboard and select cylinder so that we've got both parts selected up here on the menu around about the middle you'll see this option to make a cut out of two shapes so you click that you'll notice that hole in the middle that cylinder is now gone and it's cut it away from the gear and you can see that was relatively quicker to do than if we'd have to have gone through created a sketch and gone through the traditional process we've achieved the same result we can still edit the cylinder we can do all those good things but it's just a little bit quicker i find this way tends to be better if you're designing something stand-alone something small and you need it in relatively short time again in the component tree notices place cut outside of our pot again click and drag keeps it all nice and clean and remember you can go back in and make changes to all this stuff so notice the little drop downs here so if we click on cut you'll see there's a body in there click on pad and if we wanted to go back and make changes to the gear we can just double click involute gear we're right back here and we can make changes we can hit ok and we're straight back here so if you ever need to go back through you can easily track through all these things and make those changes and that's why it's important that you keep them nested i can't emphasize that enough so now that we've created our first gear let's go ahead and create the second one and there's something else to be learned here now as well remember whenever we add something new to our design a new pass a new piece of the design it's always good practice to create a new path and make it active so we don't want to create a second gear inside of this part with our first gear that would be bad practice so again what we do we select our workspace here we click on create a new part and make it active now you can see underneath gear one we've got a brand new part we can rename this i'm just going to call it gear2 and now this is a completely separate entity to gear one we can make our own changes to this gear and not have it affect the previous one it's just a lot more manageable and a lot more efficient don't forget as well that when you create a new part you also need to create a new body so let's switch back to the part design workspace we're going to make sure we've selected gear too create the new body and there it is straight in there remember as well we can show and hide different parts of the design by clicking on the the path and hitting the space bar you can see we can toggle between show and hide in this case we're going to hide that gear because it's going to be in the way otherwise and we're just going to focus on gear 2. so with gear 2 active here we're going to click on body once again we're going to go up to part design involute gear and we're back here on this menu now last time we had 36 teeth and for this example i'm going to show you a two to one gear ratio so we're going to half that and we're going to go with 18 teeth now this is extremely important when we're talking about the module even though we've got a different number of teeth that means the gear is obviously going to be smaller and in order for the gears to mesh and operate together properly the module has to be exactly the same if you change the module they will not mesh and it will not work so if you've already forgotten what the module for the previous one was you just hit okay and i'll show you how you can see it if you go back to gear one track through your little component tree into the body double click on the previous involute gear and you can see in there our previous module was 1.39 so let's hit cancel we're going to go back now to our gear 2. same thing we can drop down through the trees hit envelope gear and we need to set our module to be exactly the same so we're going to head to 1.39 pressure angle also has to be the same we leave that at 20 degrees and these other settings also have to be the same so let's hit ok and we now have our second gear again we're gonna have to pad this so we select our envelope gear come up to pad last time we did 10 millimeters so you want to do the same hit okay we're also going to have add a hole to this like we did before so let's come back to the part workspace select the cylinder again that has a cylinder there for us remember in the part 3 drag it up to the top over gear 2 so you keep it nested click on cylinder we're going to make that the same radius as before which was five hole looks a little big but it's just for demonstration and now we're going to create a cut between two bodies so remember select the body first then select the cylinder come up to this little icon make a cat out of two shapes and there we go we've got our second gear if we minimize our tree back down and we show gear one you can now see that we do in fact have two gears here but obviously they're overlapping because anything you create in freecad generally is always centered at the origin and we need to move one of these gears so we're going to move gear 2. so what i'll do now is show you how you can calculate the correct distance that you need to move one of these gears in order for them to mesh properly it's actually pretty easy we just use a simple equation and we plug the numbers in so if you select year two here you'll notice in the bottom left there'll be a little table and there's a bunch of parameters in there if you can't see them notice there are two tabs in the bottom left you've got view and data make sure you select data in there you will have a dropdown called placement and another one called position and you can see coordinates in there x y and z we're going to move one of these gears in the x axis to ensure that our mesh and distance is correct so i'll put the equation up on the screen and i'll put in the comments in the description as well but it's super easy to follow i'm going to go through it with you now so we're going to click on the x position here and we're simply going to start with two brackets open and closed and we're going to take the module of the gears which is 1.39 we're going to multiply it by the number of teeth in the first gear plus the number of teeth in the second gear so we can create another bracket that was 36 teeth in the first gear plus 18 teeth in the second gear and then we're going to divide the whole thing by two and just hit enter and notice what that's done here is move the smaller gear over to the right but notice how it's moved it in the correct distance that's just a simple equation that you can use that makes this a lot easier than trying to sort of judge it by eye and this way at least you know that they'll be working properly and at maximum efficiency but notice that we're looking here and it doesn't look quite right yeah so we need to rotate this smaller gear a little bit so that they look at they at least look like they're meshing properly so again if we click gear 2 down here on the placement we've got another parameter called angle if we click on that we can do another simple equation here so we're going to take 360 which is 360 degrees we're going to divide that by the number of teeth which was 18. again we're going to put this all in brackets and divide the whole thing by two and there we go that is our two gears meshed correctly and ready to be used ready to be 3d printed if we rotate around you can see that the gears look really good it all looks great that's basically it i hope you found this very useful let me know down in the comments below what you think and what you're going to be using these for i'm always interested and i'm always reading the comments so let me know and if there's also any tutorials that you want to request leave them in the comment section below and i'll see what i can do as i said i'll start the video i'm still learning free card myself so if i figure out how to do some of the more complicated gears like helical herringbone and worm drive i'll make a tutorial separately for those as well so that's it for this one as always thanks for watching i'll see you in the next video you

Channel: thehardwareguy

Views: 22,525

Rating: 4.9808917 out of 5

Keywords: freecad, freecad tutorials for beginners, freecad tutorial, freecad part design tutorial, free cad, free cad 0.18, cad beginner course, cad beginner tutorial, cad beginners guide, beginner cad software, cad beginner, freecad course, free cad course, cad course, gears in freecad, freecad gears, freecad gears tutorial, freecad gear generator, freecad gear design, how to design gears in freecad, freecad spur gear, spur gear free cad, freecad 3d print gears, design gears

Id: IhcLSx2ppUY

Length: 13min 49sec (829 seconds)

Published: Mon Jan 18 2021