Calculating Feeds and Speeds A Practical Guide | Wood CNC Router

welcome to cuttin and close a brand new channel on youtube where we talk a little bit of business make some cool projects and then also go over woodworking technology so today i want to talk to you about a practical guide to feeds and speeds so i run a business a woodworking business and i have four different cnc machines anywhere from 10 to 20 employees throughout the year and so feeds and speeds are very important to me and and my company so i want to just go over a practical guide to how i calculate feeds and speeds knowing what my machines can handle what my bits can handle and really the basics of what feeds and speeds and how to determine what is right for you so first things first let's go over the number one basic principle that you have to grasp and fully understand to be able to calculate what your feed rate needs to be how what your depth needs to be all that good stuff and that number one principle is understanding what is chip load so i'm not going to show you all these crazy charts where you think you have to be a physicist to understand of that bit spinning and it it hits it this certain direction the angle of the cut i mean that's good for a lot of metal machinists and stuff like that when you're dealing with wood you know it doesn't have to be that complicated so what chip load is and all you need to know about chip load is the amount of material the bit needs to cut in order to shed the heat from the bit to the material so the bit can stay cool so let me say that it's the amount of material a bit needs to cut in order for it to stay cool and that material actually sheds the heat away from the bit out of the project and keeps the bit cool when a bit gets too hot it starts to get dull so i have this very scientific representation right here uh that i'm gonna show you with my hand and a pile of sawdust i can zoom in real quick so you can see of what that actually looks like so my hand is a cutter head on your or a cutting flute on your bit now the bit needs to take away so much material away from your project you're working on in order to stay cool if it starts taking too little like this and just a little bit in a little bit and a little bit and it's not the correct chip load this bit is gonna start rubbing okay and it almost does a rubbing action when that rubbing action starts happening it starts to warm up just like my hands do and when it warms and it keeps rubbing and it keeps vibrating and it warms up that's when your bit's going to get dull but if you continually cut enough chips away because this bit wants to cut it wants to cut into your material and actually make a big chip it's not meant to rub so whenever it cuts into the material and has this big enough chip in order for it to take the heat away from this hand or from the flute into the chip you're good now that you understand chip load let's go over a chip load chart okay and what a chip load chart is is a manufacturer's recommended ship load for a certain size of bit in order to take the heat away to properly take the heat away from the bit into the chip away from the material you're cutting to properly cool the bit right it's a tongue twister but that's what it's for right well the problem with this chart is that it doesn't take into account what type of machine you have and this is the problem that i ran into when i was first starting out with my cnc's now that i have a five foot by 10 foot industrial cnc that has a 10 horsepower motor on it i can pretty much run anything on that chart but when you have a desktop or a hobbyist cnc or even a mid-level cnc you're not going to be able to get that recommended ship load on your cnc maybe if you have an eighth inch bit or a 3 16 bit on your smaller cnc's but once you start getting into the quarter inch bit 3 8 bit half inch bit you're going to start running into problems where you can't possibly run your machine that fast and and herein lies the problem so this is what i consider a entry level tabletop or desktop cnc and what that chart doesn't take into account is someone using an entry level or desktop cnc that may not be able to handle such bits as this half inch by three inch long bit right and that's the bad news and i'll even follow more bad news on top of that this cnc or an entry level or hobbyist or whatever you want to call it desktop cnc it's probably even not going to be able to handle a 3 8 inch bit maybe not even a quarter inch bit because a quarter inch bit in hardwood i think needs to run at 350 inches a minute and the motors and the spindle may not be even able to handle or move 350 inches a minute right much less all the vibration from the bit the good news on this hobbyist cnc is that you could probably handle any eighth inch bit or 3 16 bit that you can possibly have right and another good news on the other flip side of this is that this machine is perfect for v carving it can handle any type of v bit any engraving bit sign making bit et cetera so that's the very good upside of this but like i said the downside of that chip load chart is that you won't be able to run those bigger bits and what they need to run at so what do you do right well if you understand chip load and know that powder is bad right you actually need chips to come out of your material with that that bit actually needs to make chips instead of powder you can find a happy medium in there right so when i was starting out i was actually cutting out a lot of stuff with a quarter inch bit and i was burning through bits probably 50 percent faster than what i should have been but the good thing is it's not like you're running this machine all day long cutting out bits and this is the way i get to the practical part of it right so if i was running this machine all day long cutting out stuff with a quarter inch bit i would probably waste a lot of money on all these quarter inch bits because i'm only getting half life out of them but if you're cutting out a project on the weekend or doing maybe running it two to three hours a week cutting out something with a quarter inch bit and you're running it a little bit too slow underneath that recommended chip load then you're fine i mean it's not going to make a big deal what's going to make a big deal is if you want to run it way too slow where you're going at 10 20 inches a minute and you think you're safe because you're only taking an eighth inch pass and you have this fine powdery stuff coming and you say hey you know what my bit's safe what's happening is that his bit is rubbing so much creating so much heat that it actually may break on you and probably is going to be worse than actually running it a little bit faster right so what i mean by that is you know there's a happy medium to understanding chip load and actually running you know those bits like that versus trying to run them either wide open or way too slow okay guys now let's go to this excel sheet that i made that i use in my business to help me calculate chip load on this right side over here i actually have a rule of thumb that i typed up for you so maybe if you made it this far you're really interested and you can either write that down or take a screenshot of it this is just going to be something that's gonna help you later on and you know as you go along this is just something you can reference so this is kind of a thank you for watching and um yeah so let's talk about it now rule of thumb for wood machining your past step needs to be one to two times your bit diameter so if you're running a quarter inch bit you should be running quarter inch passes up to half inch passes now if you have a hobby cnc or a entry level cnc you probably won't be able to do a half inch pass with it but just know it's it is capable of that if you have an eighth inch bit you know you can go down an eighth inch all the way to a quarter inch per pass i mean you can go less of a past step than that but you know just know it's it's capable and should be running whatever the bit diameter is is how deep your patch should go um good rule of thumb that it just really helps whatever your feed rate is divide it by two and that's what your plunge rate is going to be so example if your feed rate's 100 inches a minute your plunge rate is going to be half of that always use a ramp when you plunge the reason you don't want to go straight down is when you go straight down it's going to really it's not easy on the spindle it's not what the bit is made to do the bit is made to cut sideways so when you ramp i advise going out like a 45 degree ramp but uh always use your ramp whenever you're plunging and for those of you that have v bits out there one flute can probably go about 40 inches a minute and that would be a 20 inches a minute plunge and a 2 flute can go to 80 inches per minute i use a lot of v bits i could probably go through 30 different v-bits a year probably do over 500 hours of v-bidding and i go at 90 inches a minute and a 60 inches per minute plunge on what i'm particularly doing but just a good roll of thumb eight inches a minute can do a two flute um v bit so you go over here all i did was take down a simple chip load chart over here and so this is what all my guys use all my machine issues i mean not nothing too complicated and instead of doing all those calculations where you have to do all this math just put in an excel sheet um and you can figure stuff out so let's say i'm running a quarter inch bit in mdf right and and i want to cut some mbf so a quarter inch bit in the mdf i'm looking for that chip load in between that ratio so if your machine is um you know a hobbyist level and it doesn't have a high capacity for speeds you probably want to go on the lower end or just below this chip load right here so we're just going to go okay you're probably going to be running at 18 000 rpms and that means and it's two flutes on your bit so let's go down to 400 inches a minute and maybe up to 450. there you go so you're going to need that run that quarter inch bit a quarter inch down into your into your material at 450 inches a minute now like i said a lot of machines that can be able to capable of running this so you might have to only do it at 200 inches a minute and maybe slow down your rpms to if you're capable to 16 000 something like that and which really doesn't doesn't change that much it looks like so well let's see if it'll there we go okay so you may want to go down a little bit on that but uh once again you know your bit is not going to last as long as you would like it to but you're probably not going to run it crazy you're probably going to be doing a lot of v-bidding a lot of v-carve maybe a lot of 3-d carving which is it's not gonna ruin a bit right so you know if you run an eighth inch bit in hardwood which i do a lot i think it's 150 inches a minute at 18 000 rpms two flutes let's see yeah so that's why i say your your machine's gonna be capable of running an eighth inch bit because your feed rate's only 150 inches a minute which is which is capable which is possible on most cnc's see my particular case i'm running a half inch bit into hardwood so i have to run this at 550 inches a minute at 14 000 rpms for my stuff to get it where i need to go which is crazy and i'm actually going a half inch into my material with my half inch bit so that's what i talk about like these charts are they're recommended by the manufacturer but they're not practical so i hope this is a practical approach and i hope y'all can either take a screenshot of this or write it down or make your own excel sheet just know it it's way easier to do it this way than to do all that calculations and math and all that stuff that hurts your head so this is what my business uses and i actually have this on a save file feeds and speeds calculator for my business super simple but yet again that's all it has to be super simple so everybody i hope this helped i hope you left with more knowledge than when you started just remember about chip load and as always don't forget to subscribe leave the comments in the comment section below and remember if you ain't cutting it close you ain't cutting it right

Channel: Cuttin It Close

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Keywords: Calculating Feeds and Speeds, what is chipload, feedrate, chipload, feeds and speeds, cnc router, how to, how to run my cnc, cuttin it close, woodwork, Drapela Works, CNC guide, guide to feeds and speeds, beginner, cnc beginner, cnc help, cnc calculations, how to calculate feeds and speeds, how to calculate feedrate, CNC broken bits, correct chipload, what is feedrate, wood, wood cnc, CNC router help, cnc machining, woodworking, cnc tutorials, cnc how to, calculate, feed, speed

Id: NZ9Ko62GcJg

Length: 12min 33sec (753 seconds)

Published: Fri Aug 28 2020