CNC Basics - Everything a Beginner Needs To Know

welcome back to the channel today i have a very fun uh video for you we're going to be going back to the basics on cnc now this video is for absolute beginners who have heard those words before or maybe seen some machines around and thought that looks like fun but they have no idea how it works or what's involved if you're already cutting things on a cnc machine

then there's probably not going to be much here for you that's new but for the rest of you i encourage you to stick around you'll walk away at the end understanding a lot better what cnc machines are how they work and how to get your jobs done all right so let's start off first with what the heck is a cnc machine you've probably heard a lot of

names tossed around cnc mill cnc router cnc plasma table well cnc actually is just a reference to the technology used computer numerical control that moves the mechanism around it's a really really vague term technically your 3d printer is a cnc machine

your laser cutter is a cnc machine cnc routers and mills of course are cnc machines plasma tables vinyl cutters all those things are technically cnc machines for the sake of this video we're going to focus on cnc mills in cnc routers now even those even though you can kind of define them strictly

they get muddy too generally speaking when you're talking to a maker about a cnc router that is a system that's predominantly used to cut wood when you talk about a cnc mill that's generally a system that is much beefier and heavier and intended to be cutting metal there's lots of

overlap you'll see people cutting metal on routers made for wood you'll see occasionally people cutting wood on a metal cnc mill really for the sake of this video you don't need to worry about that we're just going to be talking about the extreme basics of cnc mills in cnc routers [Music]

so let's start with an anatomy lesson cnc mills come in all shapes and sizes there are itty bitty tiny ones like this little tormach here and there are some the size of entire buildings they all have some things in common though some basic parts that you'll see on every

cnc router and mill in some form or another some are enclosed some are not but what you'll see on almost all of them is there is a bed of some kind and a cutting head that can move around to do the cutting and by some combination of the bed and the head moving or maybe just the head moving you

have the ability to cut on three axes of course there are machines that go up five axes four axes and more but again we're staying basic here this cutting head here can be referred to as several different things often you'll hear the term spindle which is a kind of purpose-built motor

just for being used on on these cutting machines or sometimes you'll see it's literally just a router like a palm router you would buy at a hardware store strapped onto the gantry the tools that mount in here that do the actual cutting are called end mills they look kind of like drill bits

but the actual shape and geometry of the little cutting edges is different than your standard drill bit these are purpose built for the job of being run on a mill to cut materials they come in a wide variety of shapes and sizes all the way down to itty bitty tiny

ones for getting super fine details up to you know on a very large machine you could have something a foot wide that is there just to take off lots of material now that we've covered kind of the most basic anatomy of a cnc machine let's talk about the actual process of using one if you're familiar with 3d printing you could be forgiven for

thinking that it's the same but it's actually quite different um you know in 3d printing you download your file you throw it in a slicer you select the quality you go to your machine you load your filament you hit go and more or less it prints what you want you know excluding any

failures in cnc milling machining routing there's a lot more to it first you start off by designing sometimes people design in 3d sometimes people actually distill design in 2d then you go into your tool path construction you use software to create the paths that the head is going to have to move that's right it's not like a 3d printer that figures it out for you you

actually have to figure it out for yourself you have to tell it how fast to spin the spindle how far to move what direction to move and things like that then there's actually mounting your material onto the machine that's called work holding after that you have to tell the machine where

everything is it doesn't know where everything is and then finally you run your job after you've cut it then you need to clean it up we'll go through all that let's jump into it design for cnc well it's pretty different than designing for a 3d printer for one thing you have to think about the fact that on a standard 3-axis machine your cutter is coming straight

down at your material so it can't do things like get underneath the material over here so you really can't do things like overhangs at all unless you're going to get into more complex things like moving your material around of course that excludes fancier machines that have multiple

axis heads people still design for cnc in 2d what i mean by that is they'll open up a program like adobe illustrator or escape and they'll just make lines and use those as the basis for the next step

so designing for cnc is different than designing for a 3d printer and typical tools people use for that are cad occasionally like i said you'll see people using vector software like inkscape but typically they'll use cad like you know fusion solidworks stuff like that you

can design in 3d you just have to be aware of the limitations of your machine [Music] so after you've designed your file you're ready to cut it you can't just tell the machine to go unlike 3d printers you have to actually tell a cnc machine exactly what you want it to do you

have to tell it how fast to spin the tool how fast to move the tool and how much of the tool should be engaging with the material at a time that's a lot of stuff to keep track of there are fancy calculators out there that can help you figure all those things out and the manufacturers of

these tools often publish kind of a best practices that you can use depending on your machine this is often referred to as feeds and speeds those numbers of how fast it spins and how fast it moves those are feeds and speeds the general process of coming up with all of those paths is called cam so

if you look around or google the term cam software what you're doing is you're finding software that allows you to come up with those tool paths some software does things a little bit more automated and helpful like in fusion and i believe solidworks also has some stuff where you

can kind of choose a shape and tell it you want it to do kind of a rough milling of that shape and it will figure out the best tool paths for you another thing that you have to consider when you're doing cam for a cnc machine is the fact that it is going to have to use multiple tools

most likely let's say you want fine detail it doesn't make any sense to do your entire cut with a super tiny little end mill because it'll take ages and ages instead you start with something big you take away all the material you can leaving a little bit behind and then you come back with your tiny end mill well you're gonna have to go into the software into your cam software and tell it

cut with this tool this way then switch tools and use this other tool this other way it takes a lot of practice there are tons of tutorials out there to help you though as well as books we've got some books in our maker shed that'll walk you through that process some software for doing cam you know fusion 360 has it solidworks is getting it solid works for

makers it's getting it this summer there's pi cam freecad has a plug-in that will do cam i think open builds also has some software that will do cam lots of options out there after you've got your tool path set up you've done your cam you actually have to put your

material in the machine that uh it sounds easy but it's actually more complicated than you would think this is a whole area typically referred to as work holding where you're securing your material into the machine your material is going to experience forces both down and up depending

on how the tool is cutting it as well as side to side so you have to fasten it down really well typically you see this done by some kind of clamp system but with a cnc router you have to be extremely careful because the cutting head as it moves around can theoretically hit your clamps

so there are lots of workarounds for this i shared a tip i learned you know from nyccnc on how to do like a double-sided super glue kind of rig there are wooden screws you can actually use to stick through uh sheets of plywood so whenever the cutting tool hits it it's no big deal there there are lots of options out there it's called

work holding and you're gonna have to get familiar with it if you're gonna do cnc [Music] up next are offsets so you've got your file prepared you've got your material on the machine you think you're ready to go not quite the thing you have to do next is tell the machine where the material is here in the states we call that offsets i've heard it referred to as

datums in the uk if i'm wrong sorry about that but here in the states we call them offsets when you turn your machine on first it's probably going to want to home itself kind of like a 3d printer not all machines do this but a lot do and that tells it where the edge of its bed is where

the edge of its work area is but your machine has no idea where that material is that you put in it would it know right so what you have to do is you have to tell the machine where that material is when you are doing your cam programming you chose a point on your machine to be the zero point um

and and that's going to be where you will tell the machine this is that point i told you about and then it'll kind of know where your material is okay so you know you put a shoebox size thing in there you told it this corner is the point you're going to do you're going to move your machine over there you're going to bring the tool all the way down

you're going to touch that corner and you're going to tell the machine this is my work offset it it gets confusing with all the names but basically you're just telling the machine where your material is otherwise it would have no idea this is also why it's extremely important

that you measured your material accurately you have the same material you programmed into it and things like that your machine has no idea it's going to run the program and if you have for example a tougher material or more material than you programmed it for it's going to crash now for the fun part the actual milling you've got the program in there you've told your machine

where the material is the materials held down solidly and now you get to start cutting stuff absolutely it's fun it's the best part but there's some stuff that goes along with that first off your machine has no idea what's the end of the spindle it has no idea what's out there so you actually have to tell it how long that tool is different machines have different ways of doing

this sometimes you program it in whenever you're doing your your cam stuff sometimes the machine has a touch plate where it can do it automatically it can come down and touch something a probe and that tells it how long that tool is and other times it's done at that point when you're creating your work offset the last step you're touching it and it knows that as far away as you are that's

how long the tool is now remember earlier when i said sometimes you have to use multiple tools that absolutely means that in the middle of your job you're going to have to take off your old tool put in your new tool and tell the machine how long that tool is for some machines again it's a matter of just typing it into an interface you measure it super accurately you type it in

for other machines they can come over and touch off on that probe again there's lots of ways but it's important that you do that because if you don't you're going to crash after you've told it how long your tool is you hit go it cuts through it cuts your shape it's beautiful it's wonderful we love that part cutting is fun now real quick before i go to the step after milling i'm going to talk

real quick about fixturing fixturing is a specific type of work holding so let's say you made your object and you actually wanted to make 20 of the same object fixturing would be like if you made a bracket that held it just perfect so that you didn't have to go through the entire process of setting everything up from scratch each time fixturing is a type of work holding

but usually again this is extremely basic usually fixturing is used so you can repeat a process over and over and over and over without having to come up with fresh cam and do your offsets fresh each and every time you run the job [Music] your job's done your job is cut now comes the cleanup you're going to have to take it

out of the machine and usually a cnc milled piece is going to have some things that need cleaned up sure especially when you get into machining metal there are some things that you pull it out and it's just beautiful and it's done but generally speaking especially if you're working with wood you're gonna have to do a little bit of sanding to get rid of the marks the tool leaves behind

or if you're using it for joinery on woodworking maybe you wanted it to look like traditional woodworking so you left the the inside pockets rounded and you have to go in with the chisel and chisel those out a little bit you know there's lots of little cleaning things to do even on metal machines when you're milling often you're going to want to

de-burr you know take that edge off of around things you cut and maybe even throw it into you know a sandblasting medium or a vibrating polisher or something like that generally again it's a generalization you're not pulling completely finished parts off of a cnc machine

so that's it those are the extreme basics of cnc machines you might be more confused now than you were starting out but i hope i answered some questions about the basics of how they work if you're looking to buy a cnc machine you really need to ask yourself a few questions to help narrow down so many of the options what do you plan on cutting is it wood is it metal what kind

of metal things like aluminum and brass can be cut easily on a machine that is intended for wood things like steel and titanium not so much if you wanted to do wooden furniture you wouldn't buy a cnc mill meant for metal typically because they have a smaller work envelope to trade off for the extra weight that they have to add for rigidity so you need to ask yourself what

you're going to cut how big is it that you're going to cut and of course what your budget is if you are going to be doing predominantly wood google cnc routers if you're going to be doing predominantly metal cnc mills like i said before there's tons of overlap but that will kind of get you pointed in the right direction thank you for joining me i hope this

video was at least a little bit useful to some of you out there who have been curious about cnc machines but haven't really dove in to figure out what it's all about yet be sure to subscribe to this channel give us a thumbs up it really helps us and we'll see you on the next video you