How To CNC Cut Metal For Under $400

my video about this craptacular little cnc machine has over a million views on it which is like mind-blowing to me and it's just it's so awesome uh thank you by the way to my loyal viewers you guys are awesome anyway that video is a little long on the tooth and it's time to update it so the first thing that we need to talk about as far as updates go is the uh software the the software that generates the tool paths for actually you know telling the machine where to move to cut out your part and the software that i showed in that video was called artcam which was an autodesk product and autodesk the you know the publishers of fusion360 and autocad autodesk has this like really robust history of buying up programs from smaller developers and offering them for free giving them away for free before just killing them dead you can't get them anymore or before making them something that's expensive and you have to pay for it so um auto or artcam is no longer available which kind of sucks but uh the original publishers apparently were able to hang on to their code base and their intellectual property and they are reselling artcam under the name carvco and they do not advertise this because i think that's probably their in the contract they can't say the the former formerly called art game but it's definitely formally called rcm carvco is artcam so um yeah everything that you learned about art came in that last video go buy carveco and you'll be able to use that knowledge and carveco certainly seems like a like one of the best options out there for the diy er in uh cnc machines so it's worth it it's worth it to look into but i think there's a free uh version there's a free um workflow that we can come up with to cut do some good cuts here on one of these machine like this site so that's something that i'm going to teach you in this video is just how to do pretty much anything you well not anything but do some very um you know high level uh tool path generating for free so that's thing one and the second thing to talk about to update from that original video is the machine itself this one is terrible you don't want this the only uh realistic thing you can do with this machine is um cut out some circuit boards some pcbs which now that we have glb pcb or i don't know what is it osh park or whatever we have all these companies where you can get professional circuit boards you shouldn't be cutting your own circuit boards it's really a waste of time so we want a real robust machine and this one here in the background is that this is the what is it the fox alien 4040-xe and i did the live unboxing and assembly of this uh cnc machine today and i'm super impressed i think this is the sweet spot i think this is about the size and about the money that everybody should be spending uh on a cnc machine if you don't want to be frustrated then you really want to do some good work but it's a thousand dollar machine which i know is way out of most people's budgets and i know what you guys want if you want a machine that's like this size you want to spend like less than 200 or at least less than 500 on it and you want it to be able to cut aluminum so you can make i don't know brackets for your motorcycle or you know little mechanical parts for a pew pew or uh you know stuff like this so i get it i know what the goal is and i think i've got an option for you guys so that's what this video is going to be all about we're going to find a machine that's basically the updated version of this and we're going to learn how to use it so let's see what we've got here yeah so looking at these plates i mean just look at how thick that is it's all metal it's all aluminum these bearings here go everywhere so no bushings anymore that are gonna wiggle on us uh this looks really promising i think we'll be able to to get a good router out of this [Music] all right i've got the machine fully assembled and it is a sexy beast i am loving this thing you guys so let me talk about some of the fantastic features first of all i love the red anodized colors on all of the plates awesome the lead screws are integrated into the stepper motor so that's glued into the you know the the armature inside the motor there so that's just a very nice connection that doesn't require either a a rigid connection or a flexible connection as we typically see with stepper motors unlike 3d printers there's actually a retaining bearing and then this metal knob for adjusting the axis so very high quality feel to the components there it's a really well designed simple but just really well designed kit so yeah i am very impressed with this machine for the price that i paid for it but i do have a couple of small criticisms that they're pretty minor uh the first one is this flux ring now this goes around the the motor here and it contains the invisible magnetic flux into the motor a little bit better which increases the the efficiency of this motor by about five percent so it's a small increase but it's worth it and as it comes from the factory that does not fit in between the plates so you've got to trim that flux ring down so that it will fit in between those two plates now the next problem i have is a little bit more serious and involves the um the anti-backlash nut on the lead screw so if this was a more expensive cnc machine we would see a ball a ball screw here instead of just a regular old lead screw um and ball screws have lower lash or also called backlash but it lashes just the term there um and so yeah the the anti-backlash that does help but if you don't install the anti-backlash nut correctly uh this problem happens with the bed where you get a bit of play in the bed now that bed is moving the thickness of a piece of paper and uh that's pretty substantial and it's gonna manifest in your final geometry when you're cutting things so we definitely want to fix that and here's how you do that this is the spring that comes with the anti-backlash nut and we need to shorten it so that it can work correctly so take a look at this picture where i'm holding the spring compressed next to the anti-backlash not fully installed so you need to match that gap there underneath the shoulder of the of the nut in this case i need five and a half turns there we go see how tight that is we should have no more problems at least not the normal operating forces of this small machine okay so i think i've got this thing tuned up as good as it's going to get in its stock configuration so let's talk about just what makes this machine so much better than all the other comparable machines like literally i wouldn't buy anything that's less expensive than this there's a whole lot of 200 options but they're they're junk let's talk about the stiffness of this machine versus this machine here shall we so these are pretty similar size machines i do think the bed on this one is just slightly smaller than this one which is already starting to have an advantage as far as stiffness goes and so this little stick here is going to be a demonstration if i hold this right here so you know effectively that's the length of my of my structural member and i try to bend it not happening but if i go the extra length totally can bend it and if i flip this on its side now this is twice as thick as that and i apply that same amount of force that you just saw me applying i can't bend that stick at all so we have a number of things at play here first of all the thickness of the member uh also the total length of the member um now uh that's key the length because look at all these other machines that i'll flash on the screen these are your you know under 500 cnc machines available from china and as you can see every one of those machines is larger than these two machines which means that it's just going to be less stiff based on the length if you want to keep the same stiffness and increase the you know the the cuttable area of the bed you're going to have to bump up the rigidity of the frame which means making the frame larger but most importantly it means making these linear motion rods thicker in diameter so even these two machines have a difference in that so this is 12 millimeter rod and this is eight millimeter rod and i looked it up i hadn't done these equations for about seven years since i was in school the moment area of inertia of a cylinder that's the equation there on the left so for the eight millimeter rod we have 201 and for the 12 millimeter rod the moment or area of inertia is 1018 uh you know rounded of course um so that's huge five times more stiff than this one just by by being 50 uh you know larger in diameter so just an enormous improvement uh which should make that critical you know it's always the motion system where you get the most flex out of a machine however everything about this machine is also beefed up this is um 40 millimeters thick uh extrusion whereas this is just 20 20 extrusion so it's 20 millimeters there and on the side there uh that's a lot thicker than 40 that might be 50 everywhere we're considering so a pinned connection well i'm sorry a rigid connection it's not a pinned connection much more rigid-like than this attachment mechanism here for this machine so we're already stiffer there but the the problem between these you know with this machine here is the 10 millimeter thick plate is still half as thick as the 20 millimeter thick um you know extrusion there so theoretically this machine could do that um could flex in that direction but not so fast because what we have here is some more of that 40 millimeter extrusion with two bolts uh holding it you know rigidly to the uh to the plate and then of course the six bolts there which means that we have a rigid frame going on here and that is not a very long distance between those uh those cross members so um contrast south with this that's a pinned connection for sure at the top of that very long run everything about this frame is stiffer than this one and what we're left with the achilles heel uh of this machine as far as stiffness goes is this axle going through the motor and that is a five millimeter axle and behind this uh this bit of plate here is the joint between the collet and the and the axle and um you know there's that moment where it can bend um and actually the axle can bend in between the uh the bearing up here and the bearing down there like internally to the to the motor as well we'll see what it does once i try to cut with it let's take a quick minute to talk about the control board on this uh little cnc machine so that is a chinese clone of an arduino nano as you can see right there this is the on off switch push button on off switch there's the power jack these are three uh polu a4988 stepper motor drivers obviously chinese clones on those um yeah so these are going to be terrible for the micro stepping they are not very fine resolution and also they're very noisy but we don't really care about that kind of a thing when we're going to be making all kinds of noise cutting through things so those are going to be the quietest part of the machine this here is the the power you know and ground signal that are going to the uh the spindle motor and this is the mosfet that hopefully will give us pulse width modulation so spindle speed control so all in all it's a pretty decent little cheap control board and just like all uh cnc routers it's just for some reason it's still the paradigm that you have to keep it connected to your your laptop which is running a dedicated software controlling software that's going to be sending the g-code line by line or maybe in packets of 10 lines or something like that to the controller here but if this gets unplugged from your computer mid job then the whole job is ruined speaking of connecting the cnc machine to the computer uh let's make that happen right now so i will link this uh webpage here in the description and this is the universal g-code center that goes along with gerbil now gerbil is the um the software running on the arduino that controls the machine so um the universal g-code sender you can get two versions of it actually you can get the classic version and you can get the uh the more modern version so if you go to downloads and then download page you can see that there's the classic version and the platform nightly version now i'm gonna go with the platform version just because it looks fancier the classic version i'm sure will work just fine okay and once you've downloaded that it's a zip file right here you unzip it and you go into the bin folder and then you just double click on the uh on whichever version you want to install i installed the uh the normal version not this not the 64-bit i don't really think we need 64-bit functionality for this tiny little program and also i don't have java installed for 64. and this is what the program looks like when you first open it up so uh this welcome page probably full of lots of good information for all of you all uh but i'm going to close that out i'm also going to uh i want to see this job controller here that's that's very important to me so i'm going to put that part right oh i don't know let's put it right there there we go uh so now we can see jog is front and center this visualizer here is where we're gonna watch the job happening once i'm sending a job um send notes i don't really think that's all that important the digital readout uh is more important to me this is some pretty fancy stuff you used to have to pay a bunch of money to get a machine well you used to have to pay a bunch of money to get any machine that did any of this stuff but the digital readout uh just tells you um you know what what everything's doing what your x y and z coordinates are at so currently it says i'm at 10 10 um i'm i'm not though i need to reset that so let's actually reset home right here so that's the reset zero in the top left and that basically just tells the machine that where it's at is the home position and looking at the machine we can see that i positioned it to the lower left corner as far as it will travel and the bit is just touching this uh this material that i'm going to be cutting the stock material so i want to call that my zero zero coordinate so here on the software i can just hit the reset zero button and that will declare this position as the zero zero now um on the right in the visualizer we're noticing that zero zero is supposed to be in the center of the bed or the center of the workpiece so there's different ways of um conceptualizing your workspace and personally i like to work in the positive quadrant so let me show you what i'm talking about okay you remember the uh the grid of points graph from math class in grade school i hope that you if you don't remember this you're going to have a hard time with cnc machining okay so this is your zero zero coordinate it's the place where you know things switch over from positive numbers to negative numbers so in this quadrant we are at the positive x and positive y and i like to work in this quadrant just because intuitively speaking it's easier for me to understand basically if i see numbers closer to zero i know that i'm you know very much running out of room on my bed but you also have different quadrants here this would be negative x and positive y and this would be negative negative so both negative x and y and this would be of course positive x and negative y um now some of the diy programs that we're going to talk about here in a few minutes use the zero zero coordinate not as the lower left portion of your stock material but as the dead center of your workpiece and i don't like that approach i just my brain doesn't like to wrap around that because i'm seeing a whole lot of negative numbers when i'm looking at the digital readout and it's just hard for me to orient in space i really like working in the positive quadrant so that standard to me is the standard that everybody should be you know going by um but hey chime in in the comments if you have a good reason why the zero zero would ever be the uh the center of your work piece anyway um you need to understand this because you need to understand the movement of your machine if you are at zero and you start moving along the x-axis you're going to see numbers that are increasing so that is a positive movement so this direction is a positive movement in the x direction and if you are up here somewhere and you're decreasing your numbers are getting smaller and smaller that's a negative movement in the x direction and of course the same is true for y that's a positive movement in the y direction that's a negative movement in the y direction and then z towards the camera here that's a positive movement in z and away from the camera back towards the origin that's a negative movement in z so that's how you do that anyway yeah we now have a fully functional machine we can jog it in the positive x direction we can draw in a positive y direction notice that the bed moves down because relative to the bed the bit is moving up through the stock material one thing to note about the universal g-code sender here is that there is no button uh to turn the spindle the the motor you know with the bit in it to turn that on and off um uh there should be a slider because we have pulse width modulation so we can control the speed of the spindle even but it's just not here there's no interface button so the way to do that is to type um m three space s and then a number and the number is between zero and a thousand we're one thousand is fully on so we'll just turn this thing fully on right now and it's gonna be kind of loud now we'll go m3 space s one hundred so we'll turn it on at ten percent m three space s zero that's how you test to see if your spindle is working but you don't need to do that very often those commands are going to be embedded in the g-code files which you'll be sending to the machine now if for some reason you didn't have all this working correctly um like your your the firmware came installed incorrectly on your machine uh you can go here to the gerbil uh wiki page i'll link this as well in the description um and yeah this s3 or i'm sorry it's dollar sign three command inverts the uh the the axes so you go to this table right here above the dollar sign three command and for instance if you only need to invert the the y-axis you would put dollar sign 3 equals 2 because c the y-axis has a yes so it will invert and the x-axis and the z-axis will not invert so dollar sign 3 equals 2 and you would just plug that in here in the universal g code center right here on the bottom where it says command so pretty easy stuff uh just have to follow the documentation so yeah now we're ready to move on to creating the cut file which means we're going to have to use two other bits of software so let's talk about that for a quick second so in order to get this machine to be fully functional we're going to be daisy chaining several pieces of software together so starting off with the uh the machine here which is running the just the gerbil software so this is uh this is the firmware uh on installed on the arduino um and yeah it just all this does is it takes you know movement commands and actually translates them into motor movements that physically move the machine so in order to you know get the movement commands which this thing doesn't generate what we're going to do is we're going to use another firmware which we our software which we're already using here and this is the sender so this is the universal g-code sender um which you know is also in the gerbil ecosystem open source free software now there are of course other versions of these uh you know firmwares and softwares and sometimes um you have them sort of wrapped up together um in a proprietary package or even wrapped up together in a piece of hardware that just is on the side of a more expensive cnc machine so um in our case um you know we're just using this open source stuff so this is the sender sending to the arduino which is running google um now next up the stream of programs is going to be the tool path generating uh software and so this basically creates a list of movements move x10 move y 10 move x negative 10 move y negative 10 would draw a square which would cut out a square and that would be a simple list you could program that simple g code you know list by hand but we don't want to do that we want the computer to come up with all the complicated tool path lists for us so this um this is something we're going to have to come up with how do we write those tool paths and then the other thing is you know tool paths have to reference a pre-existing geometry so you need to make your shape that you want to cut out in some other programs so the tool path program is separate from the geometry making cad program so this is your cad so we go from cad to tool paths to universal g-code sender to the gerbil controller which moves the motors and so these two here these are the big question mark at the moment and uh we're going to go over some of your options right now all right this is librecad part of the libreoffice suite of open source uh software and you guys can see that i've drawn up this shape that looks kind of like a dog tag now we don't talk about this a lot here in the 3d printing community because um it's just really unuseful for 3d printing it only makes two dimensional shapes um you know does quite a good job of that but you know we need 3d shapes for for 3d printing so um fortunately 2d shapes is all that you need for doing all of the 2.5 d um type operations in cnc work so here you can see i've taken that same dog tag and i'm cutting it out of some mdf so on the left we have the the tool which you can edit the the tool path or the tools that you're using and then the tool paths are key now this isn't a full-fledged uh tool path generation program it doesn't have a lot of features and two of the ones that i would really like to see would be spiraling into the cut so instead of just sort of directly plunging down uh with the bit you want to spiral in and the reason for that is that milling bits don't like to behave like drill bits um that's not ideal and the other um functionality that i would love to see for cutting metal especially is something that i'd like to illustrate in rhino these two cylinders represent two of the same bits as they're spinning and in this instance we're pushing the bit straight through the material just augering straight through and 100 of the diameter of that bit is engaged pushing cutting through that material so that puts a lot of stress on the bit makes you likely to break the bit uh also makes it hard for the bit to clear out the chips which means uh you're going to be generating more heat which dulls your bit up more quickly so this is just a bad way to do it to just be pushing through material at 100 the width of your bit a better way to do it is uh something like this now there's many tool paths but basically you have that bit and you sort of cut a larger channel with it by going back and forth uh with the bit like that um and then you know you just progressively work your way down uh that cut and doing it like this you could be as little as like you know 25 engagement with that with that milling bit um which is going to save the life of the bit make you less likely to break it and actually make cleaner cuts so this is definitely an advantageous way to do things and it's not an option in carbide create now the other workflow that i mentioned is this one here where you start in blender and you come up with a three-dimensional shape and so i can export this as an stl file and then bring it into mac soft visual cad and then over here on the left i can use this workflow uh to go through the you know the steps to make just like i said a single tool path type but that is a 3d surfacing tool path so look up here we can see my depth of cut is like a one millimeter so for that first bit up there uh the whole depth of cut is right on the surface so you can see those those lines that's the tip of the tool that's following those lines on the surface and then out here in space you can see the lines are just sort of floating there so that would be a flat bottom but it keeps working down you know flat bottom flat bottom flat bottom flat bottom until like after what one two three four five six oh seventh pass it will get to that final depth cut right on the surface and you will have a nice undulating surface cut into your stock material let me show you guys what a true uh tool path generating cnc program is supposed to look like but yeah this is the runtime environment for rhino you know i can i can do all the normal rhino stuff let's draw a box just because we can yep great and you can see i've got a couple of lines here these are just for my reference that is the travel limits of the machine and that is the size of the bed so within those two rectangles you can see i've drawn in this box and that is meant to be my first test cut so i'm cutting it out of this stock that's what those lines are to represent the stock material just the chunk of aluminum that i'm going to be cutting this out of so let me show you guys some of the options available in a real tool path generating program starting with the tool you can declare all the all the variables for the tool and the holder so that you can model it so you get clearance so you don't collide with your stock you can declare feeds and speeds this is very important clearance plane that's how high up it's going to lift up and over your part over your stock so you don't have any collisions you've got your tolerances that you can set that comes in handy once in a while this is also like really really important you have cut direction it's called climb cutting or conventional cutting you can look that up on the internet it's all over the place but to be able to switch between those two there are times when you need to use them or hey you can use both if you want to cut really fast so um then you have your cut levels this is your depth cuts but you have really fine control over that and you have a finishing pass there you have your entry and exit so when you want to spiral in and spiral out to uh to get good um you know plunging is hard uh with a with a bit uh with a flat bit that and maybe some of these end mills don't even have the center cutting ability so you cannot plunge you have to spiral in spiral out and the free software only allows you to plunge cut just like a drill bit right so this is also a really good one here this is tabs so uh basically you're just gonna leave a little bit of material there at the bottom to sort of hold it in place and so if i click the generate button there it will generate the the tool paths so we can take a look at those and you see this bump up there that is where the tabs are happening at so if we select the whole job and then come to simulate we suddenly see our stock and we can press play and watch the bit cut through our stock and this is just fantastic to have this ability it's it's a great troubleshooter you never quite can predict everything how it's going to work when you're going through all the all the you know the settings so to be able to see your job running before it actually runs it's invaluable like i i can't imagine really actually doing cnc work without this uh you know functionality there you have it that's what uh what separates the men from the boys as the saying goes and the free software just really isn't up to snuff like not even close so this is looking good let's uh let's cut it for real this sounds horrible listen to this i mean it is working but it sure doesn't sound very good and we can see how the bit sort of leads in and then it's just trying to find a groove it's trying to move but it's bouncing all around and that's why these walls are just so ugly like those are just so chowdery and terrible now this was a previous cut that i did with twice the feed rate and twice the depth of cut and look at the size of that circle keep in mind that circle was made with this bit so look at how much flex that bit is having before it finds its home and starts to carve down the wall and even then it's bouncing back and forth across that channel so just so much movement from this bit and this machine now i think i've got a solution i've got this other er 11 collet and it's got the wider can handle the wider shank size so you see the shank size difference there it's twice as wide and we know that twice as wide equals like five times the stiffness so um yeah same size cutter more or less actually this is this is an eighth inch so that's 3.2 millimeters and this is an actual three millimeter cutting head the problem with this one is that it's got four flutes it really changes up the behavior of the cut to have four flutes so i'm hoping that this is gonna work i'm gonna try to stay away from four fluted bits on this machine uh from here on out but this is the only bit that i have that's not uh you know long and skinny like this one i stopped the cut i've seen enough see how much movement there is that's all flex in the shaft inside this motor and it might be play inside the bearings of the motor as well so clearly we have to replace the motor on this machine and this is that new motor this is a 500 watt spindle that comes with its own power supply you control it with this potentiometer it can get up to uh 12 000 rpm at the highest now that's a whole lot better than the stock machine which tops out at 8 000 rpm so it's a half again better there's this flywheel on the end here so that should smooth the the cut out this kind of keeps the momentum of the spin going so that's a nice little feature there um yeah so this thing came with this mounting solution now that's meant to slide on there and then the four bolts go through there and it it also clamps the motor while the four bolts go through but you can see the problem there's no way to mount this to that machine just it won't go so clearly we're gonna need to modify that machine but the problem is i have no way to cnc cut metal because that machine doesn't cut metal as it currently stands i need to mount this motor to that machine to cut the mounts for this motor for that machine so i'm in a bit of a catch 22 here thankfully i have a 3d printer quick timeout before we talk about the 3d printed parts i just want to talk about price here on ebay i can find this uh printer as of you know the 23rd of november 2020 uh for 290 and that 500 watt spindle with the controller for 86 dollars so under 400 for both of these and this is the geometry that i've come up with this bit here will hold the motor you can see this large circular portion here holds the motor and then the smaller circular punch outs hold the linear motion bearings as well as the t-nut for the lead screw and here it is fully printed up and installed on the machine the the tolerance was tight enough that it was actually a press fit to get these bearing blocks into the into the print so i didn't need to install the screws this is only a temporary solution and being that it's only temporary for me i printed this out of pla which is really not ideal for long term and the reason is that pla suffers from really bad creep here's an example of that so this is one of those headphone hooks that was attached to my desk for a couple of months and when this started off life that was not as spread open as it is those were parallel lines to each other so pla just glacially moves over time if it's under pressure now all plastics do this but pla is way worse than the others if this was going to be my final solution what i would have done is make it out of probably carbon fiber impregnated petg because petg suffers from the lowest creep and i think that carbon fiber additives make it suffer from even less creep so yeah this could be a final solution it really is stiff enough but in my judgment it's not good enough i want to make it out of aluminum so we'll get there now this is the other bit of geometry that i printed up it's that lid to the uh to the power supply here and you can see that it accepts the uh the potentiometer as well as uh this switch which turns the motor on a lot and then it you know just sort of tidies up the wiring so we're not going to be exposed to mains wiring now we have a small problem because this motor apparently maxes out at 12 000 rpms so up there but you know we probably most of the feeds and speeds that other people are using on the internet are down around 10 000 rpms so i'd really like to know how fast this motor is going and and there's the trick to that that we can do right now here on my phone i've got this frequency generator running i can just stop it and start it but it's playing a low note at 167 hertz and if i put this to the microphone you can hear what that sounds like so um 167 hertz means 167 times per second so you multiply that by 60 seconds in a minute gives you 10 000 you know waveforms in a minute so 10 000 waveforms is the noise that this motor is going to make at 10 000 rpm because it doesn't the motor is not perfectly balanced so you can tune your motor just like you would tune a musical instrument and in that way without having any other special measuring device you can figure out how fast your motor is going here the motor hear the tone same note so now that the motor's installed we're ready to cut some metal but we want to make sure that we're getting the maximum driving force from the stepper motors on this machine and to do that we need to turn up the the voltage reference of the vref on these uh a4988 stepper motor drivers now this machine that i have here is quite a few months old so i don't know what you guys are going to get if you order this today but mine came with these stepper motor drivers which on the surface are almost indistinguishable from the ones that i've replaced them with but for some reason the voltage ref max on this one was 1.1 volts and these ones get up to 1.8 we don't want to burn up these stepper motors but we do want to give them as much juice as they can handle so let me show you how you get vref so you need a digital volt meter and then you take your your negative lead and you connect it to uh ground pin here on the control board so with the um with the positive lead connected to your screwdriver you just touch the screwdriver to the potentiometer that's the little screw adjuster on the uh on the control board there and then you can see i've got this one set too high at the moment so i'm going to back it down until it gets to i don't know 1.3 and there is kind of a science to this um you can go read about it on the internet but i just like to do it um this trial and error method and i've found that 1.3 volts is making this machine quite powerful enough to do what i want to do so far our feed rate is 200 millimeters per minute um i don't know just going with that with that speed now at slower speeds these this machine will be more powerful but let's just uh let's just see how good this does i have here just a fish scale not for uh for legal trade so who knows how accurate this is but it'll be accurate enough and then i'll hold this and we'll just see how high we get 25 pounds so i was able to get a similar uh pull factor from the stock control boards at a vref of about 0.8 so you might want to go with that if you are not going to replace these stepper sticks okay so the machine is adjusted so that it's got a good amount of push through the material the new spindle is mounted and working fine and we're able to use the the tone generator to figure out how fast this is going so we should be ready uh to cut parts now cut cut some aluminum maybe but there's a problem you see this uh this part right here is a combination flywheel and uh fan and it basically um you know blows a small amount of air onto the uh the the body of the motor here to just keep it cool but i have no idea why they did this this part is wider than the body of the motor and so the motor you can see that air gap that light gap through there there's a good millimeter of clearance but this part here is hitting the stepper motor so i'm going to redesign this part so that we no longer have that collision happening basically the diameter on this is the same size as the motor body so we won't have that rubbing happening anymore and i didn't do anything special to this design it's pretty much the same technique that they used on the stock fan and that means that the the blades here are two millimeters at this side and then on the other side they're three millimeters so it's not very steep angle to those blades but at 12 000 rpms it creates plenty of downdraft across that motor to cool it down the one thing i kind of changed up as you can see these sort of angled pie shaped pieces there and that's just to help with the printability of it you'll just throw that piece of wave that's just sort of like built-in in support material and here's the test cut that i'm really happy with i think with these feeds and speeds and this bit i can make this work to finish modifying this machine so this is pulled straight off the uh out of the stock material you can see i left the the tabs on there just so that you guys could see it but they're easy enough to cut off they're real thin in fact i might be able to just bend them off uh they might fall off there i just do that a little bit but anyway you can see um there's other burrs you see the other burrs around the cut so there is some cleanup to do um and the interesting thing here is the fact that that hole right there is smaller than the bit itself so this was the bit that i used to cut all around the perimeter and do that central hole just just like that but for the other hole there i actually used a smaller bit a two millimeter instead of the three millimeter bit here so i was able to do a bit change in the middle of the cut job and get that hole drilled so that means that i can accomplish everything i want to accomplish as far as uh cutting out the geometry to finish mounting that motor to the frame more securely than with a 3d printed part okay so this uh here is a bottle opener and this is rough and in fact it moved on me during the cut because the tabs that i was using on this one were not as substantial they were a little bit more thin and so they broke off and this part broke loose at the very end but you can get an idea just how rough it is when i'm doing my roughing passes i've got a finished version of it here that i kind of cut the burr off filed it down a little bit and so basically what you do is you have it on a key chain you just stick it onto the bottle cap okay so i've broken the edges off of this part i pretty much just ran my knife along them just to get those burrs taken off and let's give a measure with the caliper here to see the accuracy now this part was designed to be 10 millimeters and 100 millimeters long so if we measure in this direction we're getting basically uh 10.2 millimeters there you go no matter where i measure it i get the same pretty much the same and here in the length we're getting 100.1 millimeters so um yeah that's interesting so basically that tells me that my machine is calibrated uh correctly with the steps it's moving the correct distance but that that play there is all going to be in the bit itself either flexing out of the way or more likely just in slop in the machine uh the you know using lead screws with those flimsy little springs for the anti-backlash nut um but it gets even more interesting because here in the uh in the hole this is meant to be a five millimeter hole and you can see it's perfectly almost perfectly on in the y-axis and in the x-axis it's again like 5.2 but the x-axis was the one here that was really quite good as far as accuracy goes in that direction so it looks like my tolerance on this machine is plus or minus 0.2 millimeters so that's two thicknesses of paper and that's pretty enormous but i don't know what do you expect from a 500 machine and yeah i kind of haven't been showing you guys all the tribulations and trials that i've been going through but like here's a cut where the motor was moving on me and that's why i had to increase the torque on those stepper motors because you can see that that cut path changed um and once i got the torque on the on the stepper motors i sent a job wrong with the with the with it zeroed up in the air so it dived way down into the material it was cutting all the way through that material in a single pass which is darn impressive that that spindle can cut through three millimeters of aluminum in a single pass but you can see that the stepper motors just couldn't keep up see that funky path was was the stepper motor skipping and just being dragged through the aluminum the problem that i'm having is chatter that is the number one problem as expected from these small machines that's why i bought this super you know stiff beefy smaller machine hoping that i would get no flex in the machine and you know i can't feel any um movement in these bearings but somehow in all that um the the bit is still sort of moving around and i can see it moving around as it's trying to cut through the material now it might just be flexing the bit it really might be just that um but there is a significant amount of vibration happening uh as the bit is sort of just bouncing back and forth it's supposed to travel a straight line and it's instead bouncing back and forth across that straight line so really bad um that chatter causes the uh the bits to break actually this is the first bit that i've broken but first it broke the tip off of the cutter like the very the the business end right there the most important moment on the whole cutter uh just basically um chipped off and uh that's just because of the vibrations the the chatter in there um and once that was no longer able to cut the machine was trying to push it through the material that it wasn't cutting and it just snapped that off so there's my first eighth inch single flute end mill bit that i've broken all right let's get back to it and see if we can get a successful cut i think i think i'll be able to do it but this is kind of like trying to go four wheel driving in a smart car you guys i'm sure it's been done but it's not ideal and so it begins wish me luck here on the left see this bit that looks like the dog's breakfast as they say so that's a bunch of aluminum that has friction welded itself to the bit now the cutting edge looks okay but it's not doing a good enough job clearing the chips out of the slot and so there's just a bunch of loose chips in there that have you know mashed themselves and bonded with that bit so this on the right is what one of these bits is supposed to look like this bit will never be the same obviously carbide is a whole lot harder than the aluminum so i can chip off the the majority of the aluminum that you're seeing here and it will work okay for a little while but uh it's never going to perform as good as a new bit would perform and it won't be too long until this build up happens again and the reason for that is that the surface of the carbide has microscopic pores which have now been filled up with chunks of aluminum and so you know basically there's an aluminum coating on this carbide at this point so the reason you use single fluted bits is to try to avoid this kind of a thing single fluted bits are the best at clearing out all of the debris all of the chips but without running coolant of some sort uh you're always going to have chips in those channels so this is why all cnc machines at least the good ones all run coolant and yeah it's kind of a conundrum this is this is far from ideal and the problem is that while i haven't broken a bit and the the geometry seems to be cutting acceptably the um the chatter the chatter oh my god it was so bad [Laughter] [Music] and it's um it's warbled out that hole or that slot quite badly to where there's a lot of play like this bit should fit in there uh with no play should not wiggle side to side and there's a lot of wiggling there let's have a quick discussion about um flute count and rpms so this is a single fluted end mill this is a double fluted end mill of course they go three four even five flutes although four is the highest that i've ever actually used so the lower the flutes the lower the flute number the better it is at clearing chips but the worse it is at um being strong it breaks so the two fluted bit here is going to be stronger than the single fluted bit and it's true of four fluted bits that are even stronger still although there is a diminishing return there but the point here is that a single fluted bit has only a single cutting edge so with each revolution you only get one cut a double fluted bit gets two cuts for every revolution so there's a sweet spot in metal there's an optimal speed of it's called inches per minute or whatever you want the the cut to happen with with the feed there's a there's a balance there you can't just sort of force it through so the optimal speed to cut a single fluted bit is going to be well twice as fast or i'm sorry half as fast as a double fluted bit so there's an interplay there that's very important and you need to look up feeds and speeds on a table or you need to get a program to tell you the optimal feeds and speeds it's a it's basically the core of successfully cutting metal is getting your feeds and speeds absolutely perfect and you can trial and error it yourself if you want to do that but it's best just to you know go to where the experts have compiled their knowledge and there's a science to it and you don't have to figure this out for yourself but you do have to pay somebody generally speaking to access the uh the database where where all the different combinations are accounted for okay so you guys saw the single fluted bit all clogged up with aluminum and this is my two fluted bit that we started off the video with and i've chipped it clean the best that i can but there's still aluminum coating the uh the flutes here so i can soak this in a bath of lye or some other kind of chemical similar to that and clean off the aluminum but um you know that's kind of a pain in the butt and we it's just going to get clogged up again really quick and in order to avoid clogging up your flutes with aluminum you need to clear the shavings more quickly and in order to do that i was using uh just a spray nozzle like this so i was just following the uh the cut by hand babysitting the cut and just constantly spraying on it and that worked my bits were no longer getting clogged up with uh with aluminum so in order to not have to do it manually i've rigged up this uh other air nozzle from my air compressor and you can see i've just got some 3d prints holding it in place and keeping a constant stream of air blowing on it and this is doing the job nicely keeping those chips away from the cutter so that the cutter doesn't get all jammed up but the problem with the cutter you can see is it's flinging you know shards of aluminum all over the place inside of this box that's why i'm now doing the cut job inside of this tupperware and the shards of aluminum blowing onto the electronics short off the electronics they literally you know bridge the gap between positive and negative connections so i've made this board here where i've got my control board uh pcb covered with a couple of cooling fans and i've got the uh the controller for the uh for the motor right there and i hang that off to the outside behind where the air blows so the air is blowing kind of forward and some shards of aluminum definitely still make it up and over and uh you know kind of get on top of the covers here but for the most part this seems to be working here so your if you want successful cuts using a machine such as this you will need to do something similar to this it's there's just no way around it it's time for a reality check on this uh cnc machine so i've been working on this for about well almost two years now and off and on but uh i've been wanting to do this project and i really just wanted this to be my best video ever and the saying goes the perfect is the enemy of the good and um the punch line this part right here of this video was supposed to be me using the parts that i had cut with the you know the machine itself to upgrade the machine so that i have metal brackets holding this more powerful motor in place but uh it's not going to happen and it's not going to happen for a couple of reasons first of all um even that professional level um toolpath generator that i'm using which is rhinocam amazing fantastic program if you use rhino definitely get that it's worth the money but um this adaptive tool path that does the the sweeping action that i was talking about i really need that i need that tool path to compensate for the for the lack of rigidity and stiffness in this machine i just don't have the the um i have the strength i don't have the stiffness to push through with that entire face of that bit to push through the metal even when i'm just doing a very small depth cut it just doesn't work i need to be taking smaller bites off and i think there must be some sort of a patent on that tool path because it doesn't seem that hard hard to implement so i don't understand why none of these consumer level tool path generating programs give us that functionality because it would it's really needed it's really needed and the other reason i'm throwing in the towel is because fundamentally i don't think i'll ever get this machine to work okay so even if i replace those brackets with metal and there's absolutely zero flex between the bearing blocks and the and the motor here because it's in metal i still have uh bearing black bearing blocks on shafts on 12 millimeter shafts well those aren't perfect there's never it's not an interference fit they slide so there's a slight wiggle now i didn't measure it maybe it's only a one thousandth of an inch wiggle but that one thousandth of an inch out this is this is cantilevered out there that's can't believe it a good four inches out there so we have some seriously cantilevered forces out there so one thousandth of an inch here could equate to five thousandths of an inch out there and five thousands of an inch is significant when it comes to chatter it's going to break bits and i've broken at least 10 bits trying to get this part to be made i finally thought i had it with the air spraying on it that was a massive improvement and i'm but i still broke bits when i went to get really deep i was still breaking bits so yeah this is a no-go and i can't recommend this machine to anyone because of that i mean there's more problems with the machine you can see the exposed um rods down below so all of my chips are ending up on the lead screw and the rods down below so i'd need to put some sort of a bellows or some sort of a cover to try to keep the chips off of off of that those mechanical components so all in all i it's i'm just i quit i could this type of machine that looks like this that basically looks like a 3d printer is a bad idea for cnc machines so with that in mind i'm moving on we're going to move up to the 1 000 machine there are videos of similar machines the well let's be honest this is kind of a copy of the uh the more similar machines to this so this is not the they're they're not the pioneer of this form factor and the the pioneers of this form factor uh are cutting metal way more successfully than i'm cutting it there and part of the reason is that that is well that's about the same cantilever but that's a whole lot more beefy of a mechanism all metal everywhere and a nice strong powerful motor so i'm hopeful that i can cut aluminum more successfully on this machine than i'm doing it on that stupid little machine so that's the end of it look forward to this review and to putting this cnc machine through its paces and i quit on the 1310 and you should not buy it either so yeah that's where this video stands big huge shout out and thank you to these guys these are my executive producers and these are my patreon supporters without you guys i would not be making videos so thank you so much and see you next time bye

Channel: Design Prototype Test

Views: 180,279

Rating: 4.6981339 out of 5

Keywords:

Id: EaGFQ7M04Wo

Length: 55min 15sec (3315 seconds)

Published: Mon Nov 23 2020