The intro had me laughing pretty good. You know, most of this stuff I thought I knew pretty well, and I did somewhat. But damn man, you have a great style of explaining things. You also cover a lot very well in a short amount of time. I've really been enjoying watching your channel. I'll start posting some videos when I start assembling the project I bought. Thanks for sharing!
Thanks for watching Pete. I do a lot of research to try and get it right. Then try to figure out how to make drinking something as dry as sand some what entertaining. Look forward to seeing some videos. Your the 3rd person now that is working on getting a machine cleaned up and running!
always used this principle when milling on my flimsy homemade CNC router and it really helps a lot. especially when i need to mill something deep with stupidly long stickout.
This supports my understanding that we should first try to get the most out of the smaller tool before going large. Going large means you may not be able to max your feed or depth of cut wich is inefficient in at least 10 differents ways.
Fantastic explanation. I had not thought of trying to synchronise the entry of one flute with the exit of another. Really eye-opening, thanks. This seems like something we could easily make a tool to calculate, I just don't quite have an intuition for the maths involved.
Very interesting thank you for sharing. May I add on top of that nice explanation, that shallow radial depths of cut also can potentially cause chatter, due to the normal cutting forces will tend to push the tool away more intensively. Especially on difficult to cut materials such as Nickel alloys
Outstanding explanation! 27 years ago, my mentor, an old school German die maker.....would watch me on a Bridgeport for a few minutes, pick up a few chips, analyze......and state "your feed is 10% to fast and your speed is to slow"...."chatter is about instability, poor chip morphology.....take a healthy cut". It was about "feel" vs. feed and speed charts......what does your part look like (63 RMS or better) and what color is your chip. CNC.....same applies. Awesome post!
Yeah, I know some people like that, unfortunately I'm not there yet. I understand a lot of the science but perfect execution still alludes me. CNC is really good at masking poor cutting recipes. And compared to a Bridgeport the machines are a lot more rigid.
A while back I watched this when i was having an issue with a ball endmill in a 3d milling op. This video explained why I was having a chatter/finish problem regardless of what feed/speed I used. Now I almost exclusively use bull nose endmills for 3d milling ops since they all come in 3 flute and most balls come only in 2 flute and my parts have never looked better. Thanks for posting this.
Extremely well explained and this should be required viewing for anyone who's remotely interested in machine tools and how to get better results even on manual machines. Some of this I'd sort of guessed at, but nice to know I had figured a bit of it correctly. One of my old machinist books simplifies it a bit and mentions keeping at least two cutting edges buried in the cut whenever possible. That doesn't work at the start and end of the cut, but you can easily hear the hammering at those points as the spindle splines start bouncing along with the cutting teeth having an interrupted cut. And why fly cutters are only a light finishing tool or you beat your bearings and splines to death doing large doc enough times. It also explains why an end mill can leave a slightly rippled finish on the side wall of a cut.
Wow, thank you very much for the kind words. Don't have anything to add there other then thank you. I'm just a guy in a garage having some fun on UA-cam. And thank you to my son for letting be use is punching balloon!
Well funny enough I'd just emailed a good friend in the UK a few hrs ago with what I thought was the cause of chatter sometimes and why I thought the helical flutes helped quite a bit with the problem. He'll never believe I hadn't watched this first though. :-) And no thanks required for my comments. Your videos always earn it. The theory along with the practical helps a great deal to understand what the machine is or should be doing. That's still fairly rare on YT. But I'll be much more likely to play with the VFD for speeds and some doc changes to see if it helps when things aren't going quite the way they should. My general rule up to now is to up the feed and/or slow the speed if I start getting chatter, and most times it does help. Sometimes it doesn't and now I might have a few clues about why.
Great information, I had a job operating a grinding machine for these tools and never heard any of this information, so very glad to know it I'm at a different place now and this should come in handy, hope you have more time for more videos.
thank you for the video. I'm just starting to learn how to cnc aluminium with a tormach and didn't pay too much attention to all of this. Recently machined SS and now I'm starting to understand how important all of this is and how complex it can gets. hope you keep posting interesting material like this.
Your Welcome, Aluminum is fairly easy to machine, it just likes to gum up on the cutting edge. Once you start getting into hard materials that is when you really need to start paying attention to this stuff.
Thank you so much for this video :) by far the best explanation of chatter I've seen. It can be pretty hard to get good information on milling/cnc, but your explanations were very intuitive - excellent job.
Thank you: " The rule of thumb is one and a half flutes in the cut at all times." I'll also try to get end mills with tighter spiral flutes and try that.
That's an awesome demonstration...Looks like we need to math out that perfect depth of cut to width of cut ratio depending on the number of flute, helix angles and the cutter diameter!
YES! It's on the list, I just don't have enough time in the day. I have the DNC software done, still need to work the post for Fadal, then I was thinking about this.
Glad I read through the comments.....this is basically what I was going to ask about.....how to figure out the depth and step over to make sure there's approx. 1.5 flutes engaged. I'm subbed, so I'll be looking forward to a vid about it. :)
Getting into John Saunders territory with your explanations. Both of you are very good with the presentation and explaining it in a fashion that us dunderheads can understand.
Thanks John, This was a heavily requested topic, I hope I did it justice. I'm going to make one more on face mills. Then I think we will start on the electric side of things, motors, drives, and controls.
Hi Tim and Huge thanks for the vid! I've been having issues with chatter using adaptive roughing (milling deep slots) strategies of Fusion 360. I guess I started at a very conservative stepover and it was so shallow that only one flute was cutting at some points. The most problematic point is when exiting the curved cut. Fusion says it keeps tool load constant. But when exiting and entering cuts, they of course have to start from zero. I guess when the cut starts, the stepover is thinner for a shorter period of time compared to exiting the cut. So even if the stepover is large enough in the middle of the cut to utilize more than one flute at once, at starts and ends it isn't, which causes chatter. Until now I have dealt with the problem by just lowering stepover even more, which just eases the force of the impacts, but does not help at all to even the load, which would be the best thing to do. So I think I should try to increase the stepover quite radically. In other words, go real light or go hard. What do you think about this? Sometimes is really helps to stop banging your head against the wall for a while and instead think about what you doing wrong. Way too easy to forget that most of the time :-). Sometimes you still just end up banging your head against the wall a little lighter :-D! Thanks again so much!! P.S. I also have some doubts about my spindle taper. I'm sure it has never been reground. It looks and feels smooth but how good the fit actually is I have no idea. Should remove the flange on a tool holder so I can turn it in the spindle with some blue. Also no idea on the condition of the drawbar. Are you happy with the rigidity of your Fadal?
Entering and Exiting cuts is the hardest part for just the reason you stated. Try modifying your feed in feed out rates as well. Also when your adaptive slotting if the end mill diameter is close to the slot width that can cause issues as well. Sometimes I try to step down to a smaller end mill and that can help as well. Little counter intuitive but a smaller end mill can control its engagement better in the slot. If you suspect your draw bar at all you should test it with a force gauge. Weak draw bar can really reduce rigidity. For the spindle tapper just put a really really thin layer of blue on a good tool holder and then put it in and out of the spindle a few times. You want to see two thick bands of contact one near the top of the tool holder and one near the bottom of the tool holder. The rigidity of the linear Fadal's is not as good as a box machine. But I don't think it is horrible.
Great video even though it may be over-simplified. Now address chatter issues and techniques to fine tune something like a 1/4" 3-flute endmill with 2" LOC on a finishing pass at full length. :)
Great video again, Tim. There's a whole thing on cutter deflection. I really try never to cut deeper than the flute is radially. Some cutters, end mills, have deeper flutes than others.
I think I will do one more on face mills and face mill inserts. Lots of good response out of this series. I have spent a years worth of lunch hours with some of the brightest machinists I know, we still have not run out of topics.
So if you had a wide indexable cutter, like 1" or so, you'd actually want a higher flute count rather than a lower flute count, even if you couldn't feed it fast enough to satisfy that many flutes (due to a lower-HP machine)?
What about a very deep cut that is very long? Also, for the stock, I see where the depth is buy for the other axis, is the length of the paper the step over or is the the stock size, so the paper would show the z and x axis and the y that is missing is the step over?
Great vid!! I'm still a newb, but I've never heard of the 1.5 rule of thumb. Make complete sense! I had noticed that I get chatter at times.....I would increase/decrease the rpms, then inc/dec the feed......neither seemed to have much impact on the chatter. Other times, I would run, what I thought was, a similar cut and there would be no chatter. It now makes sense that I had changed up the step over or depth. Very interesting. Since the number of flutes, flute spacing and angle are constant, it would seem to me that rpm(maintaining the same chip load) would have the least affect. The ipt would have the next "least" amount of affect. It would help to keep a flute in the cut a slight bit longer, but very minimally. So....that leaves DOC and WOC. I can see how most circumstances would dictate which of these two would be more "set" when figuring a particular cut.....if you only need to remove .125" axially, you don't have much wiggle room there. That means that WOC becomes the variable. Vice-versa. Hmmm......I can see how this is somewhat of a "black art"! lol There's so many more variables...HP, carbide over HSS, material, etc. Am I thinking straight or on a winding road to nowhere? I think I missed the vid before this......better go check on that. :)
You pretty much summed it up correctly. There are a lot of variables that go into it, the trick is figuring out which ones you can push and which ones are the keys. When you see videos of machines running at 100's of IPM and cranking 15 HP through a 1" end mill; they really are bending the tool a lot, but because there recipe keeps the load constant it does not chatter. Also helps to have a really rigid setup. I'm still trying to figure it all out, LOL! I have seen cycle times for parts get cut in half just by tweaking a few parameters.
Yeah, I can't believe I have made so many already. I checked out a few of your videos, what type of mill are you running? Table seems really high, you need a little platform to stand on! I got a chuckle on the chip cleaning video you just did. I have seen some guys adapt a shop vac to a large garbage can and just suck them right out.
I'm running a Novakon Torus Pro with servos. I'm only 5'4".....so I use that step to change tools when I'm doing it manually. Hmmm......modding a shop vac to work on a trash can.....That's an awesome idea! Thanks!!! :)
Probably not going to see a video on sharpening end mills, drill bits are my limit. I would just send end mills out. The ball bar video is coming. I'm way behind and have not even replaced the ball screw yet. The new one is still sitting on the floor in the box.
Very good video, but how do you figure out your stepover for 1.5 flute for a given diameter mill, i assume there is some "room" in that too + or - ? I have just finshed becoming a machinist but i have only done lathe work, so i know very little besides basis about milling,
Radial chip thinning is a phenomenon that occurs with varying radial depths of cut, and relates to chip thickness and feed per tooth. While these two values are often mistaken as the same, they are separate variables that have a direct impact on each other. Feed per tooth translates directly to your tool feed rate, and is commonly referred to as IPT or chip load.phenomenon that has been well understood for decades. It is the simple observation tha when the step over is 50% of the tool's width or greater at a given feed rate, the width of chips remains constant. However, when the step-over is less than 50%, the chip width becomes progressively smaller as the step over decreases Why is it important to know this? Because most of the heat generated in the tool and the steel part is removed, not by coolant, but by the chips. If you decide (for good reasons) to use step overs smaller than 50%, you will need to run at a faster feed rate to get the chip thickness back up to target. If you are not cutting at the targeted chip thickness, your heat management will be off because the chips do not have the mass needed to retain the heat, pull it away from the tool and part, and put it into the chip pile.
Very good points, a perfect demonstration of heat removal is ceramic insert milling super alloys. Those chips and the cutter come off glowing bright red. But when your done the part is just slightly warm. That is with no coolant.
What a wealth of knowledge. Thank you. One question ...why in the world would you then want a non-helix end mill? It seems that from this video it would always produce chatter.
That depends on what your trying to do. A straight flute cutter theoretically will not produce any axial forces. If you need to mill a really thin part, or a material that tends to chip or delaminate, then a straight flute cutter is the tool of choice. Its better to say a straight flute mill might chatter easier. I still get puzzled why sometimes things chatter when I think its an easy cut then the hard cut wont.
Increasing the feed knob saves your ass on manual or CNC machines. I've ran both and learned from innovators in the industry. Then you go and correct the f/s on the next run. Understanding how to calculate them in the first place is key though. You should never squawk, but if you do edge up the feed as long as the spindle load isn't higher than the cutter can handle - that results in a broken tool.
does the same principle drives the chatter in slot milling? can you please make a video on effects of depth of cut and spindle speed on chatter ie stability lobe diagram
Slot milling is another whole animal because there are more dynamics. Slotting can help or hurt. It can help sometimes by supporting the tool on each side. It can hurt if the tool starts bouncing off the opposite sides. You really can't easily predict what a safe recipe will be. RPM and depth of cut are just two of many parameters that need to be looked at to try and predict chatter. If there was a sure fire way to do it believe me there would be a program for sale and everyone would be using it.
Thanks. Excellent Explanation !! reminds me many hours of speed - feed struggle on the machine just ended by changing step over. But how to do math for that right depth and step over to make sure there's approx. 1.5 flutes engaged, specially with variable helix?
Sorry Tim, I found one calculation picture in mm but no data regarding. I am not clear about woc from that graphical calculation. Can you please explain sample calculation in comment or another video whenever you get chance. is there any formula so we don't have to always draw geometries?
Did I got it right that for any end mill with less than 4 flutes "rule of thumb" doesn't working because it always result in target WOC greater than cutter diameter?
Hello, Only if your depth of cut is really shallow as well. Keep in mind, even with a 1 flute cutter, you could still keep 1.5 flutes engaged if the helix angle and depth of cut are appropriate.
I've checked numbers and for 1/2 inch 3-flutes end mill with helix angle 30 degrees for WOC=100% DOC equals almost two cutter diameters. Maybe it's possible to show real example of that rule? Here is a pic with my calculations: drive.google.com/open?id=0B5NfNsKzoKH0Q3ZuYkd0OV9wc0U Maybe I miscalculated something?
Hey buddy, I was wondering if you could help me with a problem I've been having with milling a hybrid composite? I've been using rotary file style cutters for carbon fiber laminate panels with great success for years, but I have some hybrid Kevlar + carbon 2x2 twill weave (3mm thick) and the Kevlar always frays... I've played with feeds and speeds quite a bit but can't seem to get a clean edge with that Kevlar... Oh and I'm using distilled water in place of the flood coolant. I've seen several cutters designed for Kevlar but they don't mention if they work well on cf also, and I'm apprehensive to try them without some recommendation. Any help is much appreciated, thank you!
I have no experience with Kevlar. However if there is a cutter that is designed for a specific material I would give it a try. Your only out the cost of a cutter, some scraps, and time. Give the tool Mfgr a call and see if they will send you a sample to try out, most will. Sorry I can't be of more help.
Hi another great video. Can I ask about your into? Is that a good cut? Looks like its smearing and I don't think the coated inserts help? I'm possibly wrong as you really know your stuff so I hesitate to question. cheers. keep up the great work.
LOL Hello Stuart, you are actually the first to ask! That is an absolutely HORRIBLE cut! Don't ever do that! I wanted to make a cool action intro for the channel when I started it. But I don't have a high speed camera, my cell phone was the best I had, which is not saying much. I started at what I would call a usable speed for carbide, and it was all a blur. Kept walking the speed down until I got a shot that was not total blur. Only took about 2 minutes and it just about cost me $25 in inserts because they started chip welding and everything. You are correct and there is all kinds of badness going on with that cut. But Hollywood is all fake anyway right? ;)
That's good news. I couldn't understand. I knew there had to be a good explanation. I try push my machine to the limits. Most of my cuts are a blurr and steam. I guess one of those cameras that show balloons bursting etc is needed. Thanks for the explanation. :-)
Just a joke, you know, phone companies offer unlimited data, or unlimited this and that. Thank you for the subscription, I don't ask people to sub or donate, I figure they will do that on there own if they want to. I just put the card so people know about the patreon.
I sent you a pm via YT. I'm letting you know because I don't seem to have very good luck seeing/finding msgs to me from YT.....this way you have a heads up to go look for it if you don't get a notification. :)
people that dont understand machinery trying to cut aluminum with a cnc engraving TOY, RIGIDITY is 90% of the equation , my smallest cnc mill is 4,000 lb
your balloon example is not completely correct. as you said machine has its own resonance but if you overcome its frequency vibration is actually lowers. each machine vibrates mostly on resonance frequency and its higher harmonics. so if you increase yor speed and load frequensy hits in between resonance and harmonic or in between two higher harmonics amplitude of tool vibration starts to come down. this is why modern machines runs insert tools with low count of inserts at speeds about 18000-22000rpm (load feq is way higher than machine's resonance)
Yes, if you hit resonance points it can make things much worse. My main point was that there are other variables to change other then just feed and speed. And at those RPMs you must not be cutting very hard materials or your tooling is very small in diameter. Very high surface speeds can burn up tooling fast in harder materials, even with really good coatings.
The intro had me laughing pretty good. You know, most of this stuff I thought I knew pretty well, and I did somewhat. But damn man, you have a great style of explaining things. You also cover a lot very well in a short amount of time. I've really been enjoying watching your channel.
I'll start posting some videos when I start assembling the project I bought. Thanks for sharing!
Thanks for watching Pete. I do a lot of research to try and get it right. Then try to figure out how to make drinking something as dry as sand some what entertaining. Look forward to seeing some videos. Your the 3rd person now that is working on getting a machine cleaned up and running!
Best explanation I've ever heard on chatter. Good job Micheal, I get it now.
Thank you, Tim
always used this principle when milling on my flimsy homemade CNC router and it really helps a lot.
especially when i need to mill something deep with stupidly long stickout.
Damn I freaking love how you drew it out. Gives me a nee perpective to look at these problems
Best machining chatter video I have ever seen. You explain it so well, thank you!
Welcome
This explanation cleared a lot of unknowns.Thank you
I have 3 differents books on machining.
None of them mentions this.
I'm so glad this video exists !
Thank you.
This supports my understanding that we should first try to get the most out of the smaller tool before going large.
Going large means you may not be able to max your feed or depth of cut wich is inefficient in at least 10 differents ways.
Very good explanation of how it works. Makes sense.
Fantastic explanation. I had not thought of trying to synchronise the entry of one flute with the exit of another. Really eye-opening, thanks. This seems like something we could easily make a tool to calculate, I just don't quite have an intuition for the maths involved.
Very interesting thank you for sharing. May I add on top of that nice explanation, that shallow radial depths of cut also can potentially cause chatter, due to the normal cutting forces will tend to push the tool away more intensively. Especially on difficult to cut materials such as Nickel alloys
Outstanding explanation! 27 years ago, my mentor, an old school German die maker.....would watch me on a Bridgeport for a few minutes, pick up a few chips, analyze......and state "your feed is 10% to fast and your speed is to slow"...."chatter is about instability, poor chip morphology.....take a healthy cut". It was about "feel" vs. feed and speed charts......what does your part look like (63 RMS or better) and what color is your chip. CNC.....same applies.
Awesome post!
Yeah, I know some people like that, unfortunately I'm not there yet. I understand a lot of the science but perfect execution still alludes me. CNC is really good at masking poor cutting recipes. And compared to a Bridgeport the machines are a lot more rigid.
Excellent description of the problem of chatter. That was well done. Thank you.!
These two videos actually helped me identify some of the chatter I've been having, as a brand new and learning machinist, thank you very much.
Welcome, thanks for the feedback
mind blowned. thanks for clearing up how this all works together
Your welcome, thanks for watching.
Amazing explanation, I was having so doubts regarding chatter and you make it very clear now. Thanks a lot.
A while back I watched this when i was having an issue with a ball endmill in a 3d milling op. This video explained why I was having a chatter/finish problem regardless of what feed/speed I used. Now I almost exclusively use bull nose endmills for 3d milling ops since they all come in 3 flute and most balls come only in 2 flute and my parts have never looked better. Thanks for posting this.
I'm glad it helped! Thanks for the feedback!
Extremely well explained and this should be required viewing for anyone who's remotely interested in machine tools and how to get better results even on manual machines. Some of this I'd sort of guessed at, but nice to know I had figured a bit of it correctly. One of my old machinist books simplifies it a bit and mentions keeping at least two cutting edges buried in the cut whenever possible. That doesn't work at the start and end of the cut, but you can easily hear the hammering at those points as the spindle splines start bouncing along with the cutting teeth having an interrupted cut. And why fly cutters are only a light finishing tool or you beat your bearings and splines to death doing large doc enough times. It also explains why an end mill can leave a slightly rippled finish on the side wall of a cut.
Wow, thank you very much for the kind words. Don't have anything to add there other then thank you. I'm just a guy in a garage having some fun on UA-cam. And thank you to my son for letting be use is punching balloon!
Well funny enough I'd just emailed a good friend in the UK a few hrs ago with what I thought was the cause of chatter sometimes and why I thought the helical flutes helped quite a bit with the problem. He'll never believe I hadn't watched this first though. :-)
And no thanks required for my comments. Your videos always earn it. The theory along with the practical helps a great deal to understand what the machine is or should be doing. That's still fairly rare on YT. But I'll be much more likely to play with the VFD for speeds and some doc changes to see if it helps when things aren't going quite the way they should. My general rule up to now is to up the feed and/or slow the speed if I start getting chatter, and most times it does help. Sometimes it doesn't and now I might have a few clues about why.
Great information, I had a job operating a grinding machine for these tools and never heard any of this information, so very glad to know it I'm at a different place now and this should come in handy, hope you have more time for more videos.
I'm close to finishing up a ton of stuff, so yes more on the way.
thank you for the video. I'm just starting to learn how to cnc aluminium with a tormach and didn't pay too much attention to all of this. Recently machined SS and now I'm starting to understand how important all of this is and how complex it can gets.
hope you keep posting interesting material like this.
Your Welcome, Aluminum is fairly easy to machine, it just likes to gum up on the cutting edge. Once you start getting into hard materials that is when you really need to start paying attention to this stuff.
Thank you so much for this video :) by far the best explanation of chatter I've seen. It can be pretty hard to get good information on milling/cnc, but your explanations were very intuitive - excellent job.
Thank you Blake
Fantastic explanation!
Thank you: " The rule of thumb is one and a half flutes in the cut at all times." I'll also try to get end mills with tighter spiral flutes and try that.
So, small story. I actually applied your logic with the milling attachment on my lathe... IT VERKS!
Thanks again 😊
Nice!
That's an awesome demonstration...Looks like we need to math out that perfect depth of cut to width of cut ratio depending on the number of flute, helix angles and the cutter diameter!
YES! It's on the list, I just don't have enough time in the day. I have the DNC software done, still need to work the post for Fadal, then I was thinking about this.
That's great...All left for us to do is wait and worry!
Glad I read through the comments.....this is basically what I was going to ask about.....how to figure out the depth and step over to make sure there's approx. 1.5 flutes engaged. I'm subbed, so I'll be looking forward to a vid about it. :)
Learned so much and it makes perfectly good sense.
Getting into John Saunders territory with your explanations. Both of you are very good with the presentation and explaining it in a fashion that us dunderheads can understand.
Thanks John, This was a heavily requested topic, I hope I did it justice. I'm going to make one more on face mills. Then I think we will start on the electric side of things, motors, drives, and controls.
Hi Tim and Huge thanks for the vid!
I've been having issues with chatter using adaptive roughing (milling deep slots) strategies of Fusion 360. I guess I started at a very conservative stepover and it was so shallow that only one flute was cutting at some points. The most problematic point is when exiting the curved cut. Fusion says it keeps tool load constant. But when exiting and entering cuts, they of course have to start from zero. I guess when the cut starts, the stepover is thinner for a shorter period of time compared to exiting the cut. So even if the stepover is large enough in the middle of the cut to utilize more than one flute at once, at starts and ends it isn't, which causes chatter.
Until now I have dealt with the problem by just lowering stepover even more, which just eases the force of the impacts, but does not help at all to even the load, which would be the best thing to do. So I think I should try to increase the stepover quite radically.
In other words, go real light or go hard.
What do you think about this?
Sometimes is really helps to stop banging your head against the wall for a while and instead think about what you doing wrong. Way too easy to forget that most of the time :-). Sometimes you still just end up banging your head against the wall a little lighter :-D! Thanks again so much!!
P.S. I also have some doubts about my spindle taper. I'm sure it has never been reground. It looks and feels smooth but how good the fit actually is I have no idea. Should remove the flange on a tool holder so I can turn it in the spindle with some blue. Also no idea on the condition of the drawbar. Are you happy with the rigidity of your Fadal?
Entering and Exiting cuts is the hardest part for just the reason you stated. Try modifying your feed in feed out rates as well. Also when your adaptive slotting if the end mill diameter is close to the slot width that can cause issues as well. Sometimes I try to step down to a smaller end mill and that can help as well. Little counter intuitive but a smaller end mill can control its engagement better in the slot.
If you suspect your draw bar at all you should test it with a force gauge. Weak draw bar can really reduce rigidity. For the spindle tapper just put a really really thin layer of blue on a good tool holder and then put it in and out of the spindle a few times. You want to see two thick bands of contact one near the top of the tool holder and one near the bottom of the tool holder. The rigidity of the linear Fadal's is not as good as a box machine. But I don't think it is horrible.
incredible explanation, thanks!
Perfect explanation... thanks
Great video, very informative, thank you
Thanks Michael, trying to extend the conversation past the usual stuff.
Thank you great video for a refresher on how to avoid simplistic chatter. 👍
Welcome
I really believe : This is The Black Magic of Machining You told Us.Thanks
LOL Thank you, it might be a small part of it ;)
Great video even though it may be over-simplified. Now address chatter issues and techniques to fine tune something like a 1/4" 3-flute endmill with 2" LOC on a finishing pass at full length. :)
Ment to get the concepts across, there is a lot deeper detail into cutting metal, more then I can present for sure.
Great video again, Tim. There's a whole thing on cutter deflection. I really try never to cut deeper than the flute is radially. Some cutters, end mills, have deeper flutes than others.
Thanks G, There are so many things to getting the perfect "formula" lots of black magic for sure.
you could definitely go on for a half 'our or so about each subject. Yeah.
I think I will do one more on face mills and face mill inserts. Lots of good response out of this series. I have spent a years worth of lunch hours with some of the brightest machinists I know, we still have not run out of topics.
and I'll definitely try and add what I know. I'd like to see this continue.
Very nice and deep knowledgeable. thanks , I will follow up all your videos
Thank you
How do I tell in practice how many flutes are engaged in the material?
Great explanation! Thanks! 👍😁👍
Very Helpful
Thanks
So if you had a wide indexable cutter, like 1" or so, you'd actually want a higher flute count rather than a lower flute count, even if you couldn't feed it fast enough to satisfy that many flutes (due to a lower-HP machine)?
What about a very deep cut that is very long?
Also, for the stock, I see where the depth is buy for the other axis, is the length of the paper the step over or is the the stock size, so the paper would show the z and x axis and the y that is missing is the step over?
Great vid!! I'm still a newb, but I've never heard of the 1.5 rule of thumb. Make complete sense! I had noticed that I get chatter at times.....I would increase/decrease the rpms, then inc/dec the feed......neither seemed to have much impact on the chatter. Other times, I would run, what I thought was, a similar cut and there would be no chatter. It now makes sense that I had changed up the step over or depth. Very interesting. Since the number of flutes, flute spacing and angle are constant, it would seem to me that rpm(maintaining the same chip load) would have the least affect. The ipt would have the next "least" amount of affect. It would help to keep a flute in the cut a slight bit longer, but very minimally. So....that leaves DOC and WOC. I can see how most circumstances would dictate which of these two would be more "set" when figuring a particular cut.....if you only need to remove .125" axially, you don't have much wiggle room there. That means that WOC becomes the variable. Vice-versa. Hmmm......I can see how this is somewhat of a "black art"! lol There's so many more variables...HP, carbide over HSS, material, etc.
Am I thinking straight or on a winding road to nowhere?
I think I missed the vid before this......better go check on that. :)
You pretty much summed it up correctly. There are a lot of variables that go into it, the trick is figuring out which ones you can push and which ones are the keys. When you see videos of machines running at 100's of IPM and cranking 15 HP through a 1" end mill; they really are bending the tool a lot, but because there recipe keeps the load constant it does not chatter. Also helps to have a really rigid setup. I'm still trying to figure it all out, LOL! I have seen cycle times for parts get cut in half just by tweaking a few parameters.
Thanks!
Now to find the time to go back and watch what I've missed. :)
Mike
Yeah, I can't believe I have made so many already. I checked out a few of your videos, what type of mill are you running? Table seems really high, you need a little platform to stand on! I got a chuckle on the chip cleaning video you just did. I have seen some guys adapt a shop vac to a large garbage can and just suck them right out.
I'm running a Novakon Torus Pro with servos. I'm only 5'4".....so I use that step to change tools when I'm doing it manually.
Hmmm......modding a shop vac to work on a trash can.....That's an awesome idea! Thanks!!! :)
incredible informative to assist in endmill selection
Thank you, trying to give more "why" then just "because"
Great. Thanks a lot. this info really sets up how to plan a good cut.
Your welcome, its one of many aspects.
As always a great vid. I'd love to see a vid on how to sharpen your own end mills. Also still waiting on your ballbar vid :)
Probably not going to see a video on sharpening end mills, drill bits are my limit. I would just send end mills out. The ball bar video is coming. I'm way behind and have not even replaced the ball screw yet. The new one is still sitting on the floor in the box.
Fantastic video, thank you very much. This was the at of your videos I've watched, I've subscribed and will watch more.
Thanks again. :-)
Thank you
Very good video, but how do you figure out your stepover for 1.5 flute for a given diameter mill, i assume there is some "room" in that too + or - ?
I have just finshed becoming a machinist but i have only done lathe work, so i know very little besides basis about milling,
THANK YOU!!!
Radial chip thinning is a phenomenon that occurs with varying radial depths of cut, and relates to chip thickness and feed per tooth. While these two values are often mistaken as the same, they are separate variables that have a direct impact on each other. Feed per tooth translates directly to your tool feed rate, and is commonly referred to as IPT or chip load.phenomenon that has been well understood for decades. It is the simple observation tha when the step over is 50% of the tool's width or greater at a given feed rate, the width of chips remains constant. However, when the step-over is less than 50%, the chip width becomes progressively smaller as the step over
decreases
Why is it important to know this? Because most of the heat generated in the tool and the steel part is removed, not by
coolant, but by the chips. If you decide (for good reasons) to use step overs smaller than 50%, you will need to run at a faster feed rate to get the chip thickness back up to target. If you are not cutting at the targeted chip thickness, your heat management will be off because the chips do not have the mass needed to retain the heat, pull it away from the tool and part, and put it into the chip pile.
Very good points, a perfect demonstration of heat removal is ceramic insert milling super alloys. Those chips and the cutter come off glowing bright red. But when your done the part is just slightly warm. That is with no coolant.
Yeah I have seen bonded diamond and also ceramic.
What a wealth of knowledge. Thank you. One question ...why in the world would you then want a non-helix end mill? It seems that from this video it would always produce chatter.
That depends on what your trying to do. A straight flute cutter theoretically will not produce any axial forces. If you need to mill a really thin part, or a material that tends to chip or delaminate, then a straight flute cutter is the tool of choice. Its better to say a straight flute mill might chatter easier. I still get puzzled why sometimes things chatter when I think its an easy cut then the hard cut wont.
Ok ...thanks ...I am completely new to milling so you are really helping.
I learnt something new. Thank you and i will apply this knowledge to my work. Peace
Awesome, I'm still learning my self!
great video
mind blowing
Thanks
And how variable flute affect on this?
Awesome! Thank you so much! Is there some way to do at least a rough calculation to get in the ball park for a given end mill? Thanks
Increasing the feed knob saves your ass on manual or CNC machines. I've ran both and learned from innovators in the industry. Then you go and correct the f/s on the next run. Understanding how to calculate them in the first place is key though. You should never squawk, but if you do edge up the feed as long as the spindle load isn't higher than the cutter can handle - that results in a broken tool.
Where is this man now?
does the same principle drives the chatter in slot milling? can you please make a video on effects of depth of cut and spindle speed on chatter ie stability lobe diagram
Slot milling is another whole animal because there are more dynamics. Slotting can help or hurt. It can help sometimes by supporting the tool on each side. It can hurt if the tool starts bouncing off the opposite sides. You really can't easily predict what a safe recipe will be. RPM and depth of cut are just two of many parameters that need to be looked at to try and predict chatter. If there was a sure fire way to do it believe me there would be a program for sale and everyone would be using it.
Thanks. Excellent Explanation !! reminds me many hours of speed - feed struggle on the machine just ended by changing step over. But how to do math for that right depth and step over to make sure there's approx. 1.5 flutes engaged, specially with variable helix?
It is a little bit of trig, I think there should be a comment below with the math.
Sorry Tim, I found one calculation picture in mm but no data regarding. I am not clear about woc from that graphical calculation. Can you please explain sample calculation in comment or another video whenever you get chance. is there any formula so we don't have to always draw geometries?
Let me get something for you, will take me a bit though, been slammed lately.
Thank you !! Tim, I been finding similar resources online but couldn't found one yet.
That means mastercam sucks cuz u can't see flutes?
Did I got it right that for any end mill with less than 4 flutes "rule of thumb" doesn't working because it always result in target WOC greater than cutter diameter?
Hello, Only if your depth of cut is really shallow as well. Keep in mind, even with a 1 flute cutter, you could still keep 1.5 flutes engaged if the helix angle and depth of cut are appropriate.
I've checked numbers and for 1/2 inch 3-flutes end mill with helix angle 30 degrees for WOC=100% DOC equals almost two cutter diameters. Maybe it's possible to show real example of that rule?
Here is a pic with my calculations:
drive.google.com/open?id=0B5NfNsKzoKH0Q3ZuYkd0OV9wc0U
Maybe I miscalculated something?
Hmmm your calculations look correct. Let me dig into it more and maybe make another video.
It would be great!
Hey buddy, I was wondering if you could help me with a problem I've been having with milling a hybrid composite? I've been using rotary file style cutters for carbon fiber laminate panels with great success for years, but I have some hybrid Kevlar + carbon 2x2 twill weave (3mm thick) and the Kevlar always frays... I've played with feeds and speeds quite a bit but can't seem to get a clean edge with that Kevlar... Oh and I'm using distilled water in place of the flood coolant. I've seen several cutters designed for Kevlar but they don't mention if they work well on cf also, and I'm apprehensive to try them without some recommendation. Any help is much appreciated, thank you!
I have no experience with Kevlar. However if there is a cutter that is designed for a specific material I would give it a try. Your only out the cost of a cutter, some scraps, and time. Give the tool Mfgr a call and see if they will send you a sample to try out, most will. Sorry I can't be of more help.
Thanks for the reply. I'll try contacting a few manufacturers and if I find anything interesting I'll post it for others benefit.
Hi another great video. Can I ask about your into? Is that a good cut? Looks like its smearing and I don't think the coated inserts help? I'm possibly wrong as you really know your stuff so I hesitate to question. cheers. keep up the great work.
LOL Hello Stuart, you are actually the first to ask! That is an absolutely HORRIBLE cut! Don't ever do that! I wanted to make a cool action intro for the channel when I started it. But I don't have a high speed camera, my cell phone was the best I had, which is not saying much. I started at what I would call a usable speed for carbide, and it was all a blur. Kept walking the speed down until I got a shot that was not total blur. Only took about 2 minutes and it just about cost me $25 in inserts because they started chip welding and everything. You are correct and there is all kinds of badness going on with that cut. But Hollywood is all fake anyway right? ;)
That's good news. I couldn't understand. I knew there had to be a good explanation. I try push my machine to the limits. Most of my cuts are a blurr and steam. I guess one of those cameras that show balloons bursting etc is needed. Thanks for the explanation. :-)
No Problem ;) If your not bouncing chips off the walls your not cutting hard enough right!
Excellent video. Thank you. /John
Your Welcome John, thank you
the helix provides a shear angle
we need one on parting
Lathe Parting?
Wow !!!
Just as good on the second viewing!! :)
LOL, unlimited views with subscription ;)
Subscription? Patreon? It's not much, but I subbed. :) I've certainly gotten way more value already. Thanks!
Just a joke, you know, phone companies offer unlimited data, or unlimited this and that. Thank you for the subscription, I don't ask people to sub or donate, I figure they will do that on there own if they want to. I just put the card so people know about the patreon.
I know. I didn't take it that you were fishing...but I didn't know you had the patreon account either. :)
I sent you a pm via YT. I'm letting you know because I don't seem to have very good luck seeing/finding msgs to me from YT.....this way you have a heads up to go look for it if you don't get a notification. :)
people that dont understand machinery trying to cut aluminum with a cnc engraving TOY, RIGIDITY is 90% of the equation , my smallest cnc mill is 4,000 lb
Fadal controller :)
your balloon example is not completely correct.
as you said machine has its own resonance but if you overcome its frequency vibration is actually lowers.
each machine vibrates mostly on resonance frequency and its higher harmonics.
so if you increase yor speed and load frequensy hits in between resonance and harmonic or in between two higher harmonics amplitude of tool vibration starts to come down.
this is why modern machines runs insert tools with low count of inserts at speeds about 18000-22000rpm (load feq is way higher than machine's resonance)
Yes, if you hit resonance points it can make things much worse. My main point was that there are other variables to change other then just feed and speed. And at those RPMs you must not be cutting very hard materials or your tooling is very small in diameter. Very high surface speeds can burn up tooling fast in harder materials, even with really good coatings.