I retired 25 years ago from a naval shipyard where I specialized on large manual machine tools dating from the 40's and 50's. One project was a large cast copper nickel alloy valve body that was in essence a double 12" ball valve arranged in series. It was a complicated part that had to be sequenced through several machines to accomplish the many bores, faces, hole patterns, and other features. It started out about 1800 lb and finished much lighter. There was an O-ring face groove about 20" in diameter on a flange placed about 7" back of an extension. That part of the work was all milling and facing head work on a 6" bar floor mill. The O-ring groove posed a particular problem with chatter. The facing head had to be extended over a foot on the bar to reach the work. Needless to say with that tough material and the extended mass and a wide grooving too, there was a big chatter potential. Day shift cautioned me on the problem telling me to finish the work except the groove which was to be cut later on a 10 ft VBM. I though it a shame to set-up a part that large and complex on a different machine to machine a single feature. I tried it, feeding an under width tool. Chatter became loud and threatening in less than a second of tool contact. Then I noticed The chatter was cut away are the spindle coasted down. Hmm. The floor mill was DC powered. My solution was to constantly "warble" the spindle speed between 4 and 6 RPM as I fed in the grooving tool. Chatter had no opportunity develop resonance because the exitation frequency imprinted in the work constantly varied. I was pretty proud of my solution and left a lengthy note for day shift on the what, where, and why of warbling spindle RPM to negate chatter. I got in trouble for not following instructions but the lot of castings never went to the VBM to cut that O ring groove so I guess that turned out OK. I have a VFD on my turret mill and milling into corner has always been a pain until I remembered a lesson from 30 years earlier and warbled the spindle RPM. It doesn't take much: +/- 10% RPM seems to work on a 3 second cycle for most applications but you may need to cycle faster or slower depending on results. I'm kinda surprised there isn't a way to program spindle RPM warble on CNC machines. Hell, you got control of everthing else. Set a center RPM, a range, and a cycle frequency. Be a nice supplement to adaptive control.
Forrest Addy That's a interesting story👍. Some of the newer machines can do this now. Look at the comments on this video there is a link to a Haas video that shows this on a Haas.
Edge Precision I looked at the Haas video demonstrating the spindle speed varying feature. That's exactly what I was referring to. Excelent demo, by the way. Anyone who duplicates 4the conditions and operations will certainly secure the same results. Scientific method applied to the machine shop.
Hello Forrest Addy, i remember your posts from HSM from a decade ago. Modern cnc machines do that. Both milling and lathe. Okuma does it for turning, even Haas which is not a cutting edge machine tool company, has this feature.
Hello Forest. I remember reading your posts from (maybe a decade ago) on Web forums and always found then very insightful. I love learning more about what we do for a living so I very much appreciate the time you and (edge Precision, I don't know you're name..) spend sharing your knowledge. Thank you all and cheers
Thanks Peter. Really appreciate and enjoy the information you share so often. Getting pro tips from an expert on a regular basis is really a privilege. Your awesome!
Thank you for another great video! You definitely have some of the most profound content on the tube when it comes to "real world" problem solving and making chips. A rare find for sure!
I do a similar thing on my big lathe which has a VFD: continually changing the spindle speed through a range of about 20 or 30 Hz when it looks like getting into a chatter scenario: if it never stays at one speed, chatter doesn't start. But your crafty blipping dodge also reminds me of a good way of dressing a bench grindstone true. If you let it run up to full speed, the spindle will orbit, a bit like a washing machine when it gets past the critical speed, and the bowl starts to rotate relatively smoothly about the centre of mass, rather than the geometrical centre. When a grinding wheel does this, there is no point trying to true it, because you will lock in the eccentricity as bad geometry and end up chasing your tail. So what I do is blip the switch to keep the speed well below the critical transition speed, so it rotates around the spindle axis instead of orbiting, and use a single point diamond to cut deep enough grooves around the periphery to get below the eccentricity. Then I go back and remove the material between the grooves, finally use a T handle dresser to recover the cylindrical form.
Both of those were excellent tips! Man, I am blown away by not calling a G80 and having control to tap manually in the cnc. I will have to test this in my Haas!
I worked with a trio of Mori Seiki GV-503 pallet changing vertical mills with Meldas controls. They had a button called "tap removal" or something like that. Basically, it functioned like you show in the video, but it was for jogging the spindle and Z in synch if you hit E-stop or the power went out during a tap cycle. I think I used it once. I've never seen another machine with that specific function.
Ran a newer Fanuc Oi machine with this function. I always used to just loosen up the collet and get the tap out with a wrench when I ran any other machine.
Just tried it and it works great, just make sure setting 29 under the control parameters is enabled.This parameter enables the pitch to be the feed rate like in the video. Thanks again for sharing!!
In Fanuc Speak it is "Rigid Tapping By Manual Handle" I believe it's been around about as long as rigid tapping. Proceedure is about the same. I would guess that any "i" series Fanuc control with rigid tapping can do it for sure. If you can't, you will need to enable a parameter. Refer to your operators manual, it has a description on how to use it and what parameters need to be set. I don't think it is a special option, but comes with the rigid tapping option.
For any one interested just tried it and the "JOG TAPPING" does not work on a Mazak with M-Plus control it does work on a DMG DMC 1035V with M730BM control.
Very nice video sir, Controlling the whole program movements forward/backward with an MPG is already exists feature on Heidenhain cnc controller. IT IS SO HANDY FEATURE especially when you start a program and you don't want to hit something.
Thanks for the great video! That manual tapping cycle would be super useful for picking up and chasing threads on a CNC lathe. Hopefully my turning center has this functionality.
Wow, that manual tapping is amazing, never knew a cnc could do that. I was stunned when I can slow down the feed rate during tapping at Siemens 840d, but the is a whole different animal! Need some time to figure out what can be benefit from this future!
Hi, I have a Feeler / Fair Freind FV1600 with Meldas 64 control, this tapping does not work, you can set it in mdi but as soon as you change to jog or hand-wheel mode it loses the setting...
They must have disabled this in other controls. This is the only machine I have ever run that can do this. I only learned it by accident when I stopped the machine with feed hold in the middle of tapping some holes (Broke the tap) and jogged back the Z axis without hitting reset and noticed it was still synced to the Z axis. Than I tried what I show in this video and it worked. I don't think the designers of this control intended for this. It could be a safety issue and was disabled. If you could imagine someone grabbing hold or getting gloves or clothing on the tool holder and jogging the Z back and the spindle turns. That could be bad.
It already is in CAM softwares, like for example SolidCAM automatically can finish a pockets corners, floor and walls without touching the others and thus you get no tool chatter in those situations. Not to mention that SolidCAM's iMachining just wipes all the other CAM softwares under the table in ease of use and money savings.
Some cnc-controllers support this, although its mostly a software-option you have to pay for. For the Heidenhain controller it's called ACC (Active Chatter Control)
man that variable rpm would be realllllly nice on the 5 axis pocket nc, could probably have an rpm change built into the gcode, but it would be nice if fusion did it. perhaps some post processor investigation is in my future. So far the best roughing speed is 40 ipm with 0.040 axial, 0.010 radial with a ticn coated 1/8 endmill at an inch of stickout and 10k rpm. I need the inch of stickout to clear the collet that holds the stock(er32). Ideally I would use a 1in stickout reduced shank 1/8in endmill with less than 1/8 axial cut. edit: looked and of course harvey tool has a .187 axial extended reach line up for 1/8in endmills
sure do appreciate your awesome videos, and finally a true cnc PRO on youtube: like the CNC version of Jody/weldingtipsandtricks or Adam Boothe Abom79/manual machine work.
Which Mitsubishi Meldas control is it? I'm currently looking at a high speed tapping centre that uses the Meldas m50 controller but there is barely any info on it.
You might try this on you tm and tl Haas machines at home. I would be interistes to know if they are capable of doing this because we tap some 3/8 and 1/2 npt holes at work on our tm1. We have to run sevral taping cycles and incrimentaly increse the depth, clear the chip, run another deeper cycle and keep doing that till we hit the depth we want. I don't think we have ever tryed that with the tl1 because we just got it about 3 or 4 months ago but i do think it has ridgid taping. If you could try this on your Haas machines that would be fantastic and would really help me out!
Hi Guys. Ever wondered what is actually causing the chatter? This excellent video demonstrates that the chatter happens when the tool’s cutting face is up very close to the work. This increases from a short arc of the cutting interface when running along a straight to becoming obvious when in the corner, nearly a quarter of the cutting edge is in contact with the work. In this situation: chips are being drawn from the workpiece and driven between the cut edge and the cutter edge. This needs to flex the bit a little bit and this, combined with the sound of chips being squashed against a hard surface and pushed along {like dragging a steel table leg across a concrete floor} produces the screeching noise from which we recoil. This is Chatter. There are a couple of ways to fix this. 1) Blow a constant stream of compressed air to clean out the cutter from any swarf, and 2) Wash the cutting interface with a stream of cutting fluid ... so that this effect is minimised. You don’t get chatter on a CNC machine running optimally with flood irrigation. What was demonstrated was variable frequency chatter. Sorry, all you are doing is trying to burn out the motor with the jogging.
Those current surges will cause your motor and your switch to heat up. I prefer Joe Pieczynski's method of raising the quill, moving to the corner, and plunging the end mill using the quill.
On a CNC machine what I have found that works the best is to actually not stay in the corner any longer than necessary. I have actually programmed arcs in corners and increased the feed at the arc to get in and out of the corner faster. On some older CNC machines if you have a sharp corner defined by just two lines it can actually make the machine dwell for a instant in the corner because the control is moving to the lines intersection. This will increase the chatter in the corner. Its better to do mutable plunges working out to the corner than mill around the profile. As I said in the video I use two separate tools. One to plunge that I grind all the flutes (Or use a reduced shank sort cut length tool) but the last 1/4". And a tool to finish the walls and floor. Some times I take mutable finish passes on the wall at different levels down also. I generally finish the floor first standing off the wall than finish the walls if the pocket has a floor.
Refarding the endmill chatter in the corner I would choose a 2 flute, 4 flutes in aluminum will usually be more prone to chatter.Myself, I have actually better luck with high helix flutes than low helix in certain instances. If you can turn the rpm down low enough and feed it accordingly you can probably get a really decent finish without pulsing the rpm. Very low rpm allows a nice finish on a variety of sensitive operations, like countersinking for example. In fact, where it's possibly to turn the tool or material (in a lathe) by hand you can get excellent finishes with certain tool and parts that would otherwise make you pull your hair from frustration. Sometimes a slightly but evenly worn tool (less clearance angle) will cut nicer in corners. The cutting edge doesn't try to dig in as much. Less clearance angle and less rake are not as prone to chatter in many scenarios, of course they may not perform as well in other aspects.
Usually when I’m borderline touching the corner I would pull the quill up raising the tool. And then move over so the cutter is slightly over the radius and then just plunge down and feed away
I'm not sure on the Meldas but on Fanuc controls it uses a feature called swap axis..the spindle becomes the x axis during a tapping cycle and acts like a feed axis which is fully synchronized to the other feed axis. Until this is cancelled with a G80 it will act like the Meldas above.
That's probably so you can use a 90 deg. head. So you can jog a tap with the handle jog like I did in this video? I have never tried it on the Fanuc control. On the bridge mill we have here you just rotate the work plane say into the YZ than the X becomes the Z axis. With all the abilities of a normal Z axis tapping canned cycles exc. In fact it can be at any angle depending how you rotate the work plane like a 5axis machine. We do a job with a 90 deg. head at a 45 deg. angle to the X axis. Thanks for the Info.
I think but not 100% sure that it's to get around having to install another axis on the software side so you can do a tap cycle with a 4 axis control that doesn't normally have a software synchronized spindle which would of needed a much more expensive 5 axis controller. For example the Fanuc 18 had a max of 4 programmable axis back in the 1990's so the only way to synch the spindle for tapping was to swap another axis via software on the fly (swap axis feature). The MTB would install the servo type spindle motor which was +/- 10v analogue control with an encoder on the spindle and use the swap axis to activate it as a synchronized axis only during tapping when the x axis wasn't needed. All about keeping build the costs down for the MTB :-)
Another great and informative video :D . Just for the record , i tried this spindle speed variation ona cnc lathe (but just manually , it does not have a cycle for it) it helps , but it's not the best solution . Turns out i got a lot better result using a little(20-30%) higher feedrate and 10% lower cutting speed .
I agree its better to get the feed and speed correct. But in rare instances I have resorted to the speed override buttons and it does work but its my last resort. I don't like to have to be at the control 100% of the time with my finger on feed hold or the override buttons.
I do have a instagram as Peter L Stanton but I have never done anything with it. I'm not that tech savvy I am still learning about all this social media stuff. I need some help with that.
Not a glitch. As long as the sync is active, it will synch the spindle position vs. Z-axis position (or whatever you are using as the tool axis). Standard feature on pretty much any machine that can do rigid tapping cycles.
Yes the variation in the speed kills the vibration/chatter. On a CNC machine you can vary the spindle speed override its sort of like doing that but manually.
@@EdgePrecision I was saying it's slightly different because your killing the harmonics when doing this in a cnc lathe and not with this because a slower rpm would cut the corner correctly(vibration occurs per flute at higher rpm). I love your videos btw. I can see why you bought that mazak.
Hello Sir I'd like to thank you very much for sharing this techniques I like all and specially the manual jog threading. I really appreciate this video thanks a lot
When you see variable helix and stagger relief end mills for sale that is the purpose of them. To disturb the harmonics of chatter that result from excess radial engagement. Obvs with modern tool path we can govern consistent engagement to an amount that works well.
Yes the idea is to reduce chatter by disturbing the harmonics like you say. This does work and it can be worth paying for. It sometimes can be hard to measure the diameter of the tool. You have to make sure which flutes you are measuring.
Edge Precision I can't remember the last time I measured diameter with a touch probe. I've used an optical offline setter, laser in machine probe, and of course the old cut, measure, set, recut. The JV squad manages to break touch probes with such regularity that every place I've worked just moves on away from them :D Similarly I never really messed around with the variable flute/helix endmills. It was just simpler to "git gud" with constrained engagement toolpath. I like having the old school knowledge and in my mental toolbox to fold in as a bit of spice with state of the art recipes.
Chatter is a "harmonic" and when you have "two-phase" AC current (if its not "3-phase" its technically "single-phase" since all AC is "phased" and only a single phase exists between the two "legs" of non-3 phase current) operating machines made for 3-phase current which is "one third smoother" in power delivery, its pretty easy to have "chatter" in certain "speeds" where the number of cutters, AC frequency and "two phases" all end up "in synch" to set up a "harmonic". If there is an even number of cutters you don't want "2-phase" current because its easy for 60-cycle current and particular current ran through a "converter" to end up being "in phase" with the even number of cutters. As for cutters "in contact" the MORE cutters "in contact" the BETTER for single-phase AC and the harder it is to produce "chatter". Simple drill bits have only two cutters and work well with all types of AC and DC current because there is a CONSTANT LOAD on the CUTTERS. Chatter occurs when loads and/or power reach the tool "intermittently" and "in phase" such that a load and a lack of power "overlap".
Matt Dostou Maybe you can educate me. What was stupid or giving wrong direction? Tell me if you can. I was just showing a few things I have actually done in the past that were a help to me. I'm not suggesting they are the end all or the best way of doing things. What have you done? How is it better? Tell me if you can.
I retired 25 years ago from a naval shipyard where I specialized on large manual machine tools dating from the 40's and 50's. One project was a large cast copper nickel alloy valve body that was in essence a double 12" ball valve arranged in series. It was a complicated part that had to be sequenced through several machines to accomplish the many bores, faces, hole patterns, and other features. It started out about 1800 lb and finished much lighter. There was an O-ring face groove about 20" in diameter on a flange placed about 7" back of an extension.
That part of the work was all milling and facing head work on a 6" bar floor mill. The O-ring groove posed a particular problem with chatter. The facing head had to be extended over a foot on the bar to reach the work. Needless to say with that tough material and the extended mass and a wide grooving too, there was a big chatter potential. Day shift cautioned me on the problem telling me to finish the work except the groove which was to be cut later on a 10 ft VBM.
I though it a shame to set-up a part that large and complex on a different machine to machine a single feature. I tried it, feeding an under width tool. Chatter became loud and threatening in less than a second of tool contact. Then I noticed The chatter was cut away are the spindle coasted down. Hmm. The floor mill was DC powered. My solution was to constantly "warble" the spindle speed between 4 and 6 RPM as I fed in the grooving tool. Chatter had no opportunity develop resonance because the exitation frequency imprinted in the work constantly varied.
I was pretty proud of my solution and left a lengthy note for day shift on the what, where, and why of warbling spindle RPM to negate chatter. I got in trouble for not following instructions but the lot of castings never went to the VBM to cut that O ring groove so I guess that turned out OK.
I have a VFD on my turret mill and milling into corner has always been a pain until I remembered a lesson from 30 years earlier and warbled the spindle RPM. It doesn't take much: +/- 10% RPM seems to work on a 3 second cycle for most applications but you may need to cycle faster or slower depending on results.
I'm kinda surprised there isn't a way to program spindle RPM warble on CNC machines. Hell, you got control of everthing else. Set a center RPM, a range, and a cycle frequency. Be a nice supplement to adaptive control.
Forrest Addy That's a interesting story👍. Some of the newer machines can do this now. Look at the comments on this video there is a link to a Haas video that shows this on a Haas.
Edge Precision I'll do that.
Edge Precision I looked at the Haas video demonstrating the spindle speed varying feature. That's exactly what I was referring to. Excelent demo, by the way. Anyone who duplicates 4the conditions and operations will certainly secure the same results. Scientific method applied to the machine shop.
Hello Forrest Addy, i remember your posts from HSM from a decade ago. Modern cnc machines do that. Both milling and lathe. Okuma does it for turning, even Haas which is not a cutting edge machine tool company, has this feature.
Hello Forest. I remember reading your posts from (maybe a decade ago) on Web forums and always found then very insightful. I love learning more about what we do for a living so I very much appreciate the time you and (edge Precision, I don't know you're name..) spend sharing your knowledge.
Thank you all and cheers
Thanks Peter. Really appreciate and enjoy the information you share so often. Getting pro tips from an expert on a regular basis is really a privilege. Your awesome!
Thank you for another great video! You definitely have some of the most profound content on the tube when it comes to "real world" problem solving and making chips. A rare find for sure!
I agree with Mike.
Steve
I do a similar thing on my big lathe which has a VFD: continually changing the spindle speed through a range of about 20 or 30 Hz when it looks like getting into a chatter scenario: if it never stays at one speed, chatter doesn't start.
But your crafty blipping dodge also reminds me of a good way of dressing a bench grindstone true.
If you let it run up to full speed, the spindle will orbit, a bit like a washing machine when it gets past the critical speed, and the bowl starts to rotate relatively smoothly about the centre of mass, rather than the geometrical centre.
When a grinding wheel does this, there is no point trying to true it, because you will lock in the eccentricity as bad geometry and end up chasing your tail.
So what I do is blip the switch to keep the speed well below the critical transition speed, so it rotates around the spindle axis instead of orbiting, and use a single point diamond to cut deep enough grooves around the periphery to get below the eccentricity. Then I go back and remove the material between the grooves, finally use a T handle dresser to recover the cylindrical form.
That's Interesting I will have to remember that. Thanks.
Both of those were excellent tips! Man, I am blown away by not calling a G80 and having control to tap manually in the cnc. I will have to test this in my Haas!
I worked with a trio of Mori Seiki GV-503 pallet changing vertical mills with Meldas controls. They had a button called "tap removal" or something like that. Basically, it functioned like you show in the video, but it was for jogging the spindle and Z in synch if you hit E-stop or the power went out during a tap cycle. I think I used it once. I've never seen another machine with that specific function.
Then NGC HAAS mills have a tap recovery button.
Ran a newer Fanuc Oi machine with this function. I always used to just loosen up the collet and get the tap out with a wrench when I ran any other machine.
Excellent tip on the G84 canned cycle Peter !! I have a couple of Haas Mini's I am going to test this on.
Just tried it and it works great, just make sure setting 29 under the control parameters is enabled.This parameter enables the pitch to be the feed rate like in the video. Thanks again for sharing!!
I'm curious what make and model of machine did this work on? You didn't indicate it in your comment. Thanks.
Sorry I didn't connect to your earlier comment. It being a Mits M50 H.
MITSUBISHI MH50E With a Meldas 520 control 1997 .
Jog tapping....I cant wait to try that!
This may not work on every machine or control. As I say in the video I just accidently stumbled on it with this Meldas control.
I've been doing the plunge method in the corners routinely for 30 years. Works great most of the time. Keeping the revs down helps a lot, too.
In Fanuc Speak it is "Rigid Tapping By Manual Handle" I believe it's been around about as long as rigid tapping. Proceedure is about the same. I would guess that any "i" series Fanuc control with rigid tapping can do it for sure. If you can't, you will need to enable a parameter. Refer to your operators manual, it has a description on how to use it and what parameters need to be set. I don't think it is a special option, but comes with the rigid tapping option.
For any one interested just tried it and the "JOG TAPPING" does not work on a Mazak with M-Plus control it does work on a DMG DMC 1035V with M730BM control.
coolest think I've seen this year, absolute madman :D
Very nice video sir,
Controlling the whole program movements forward/backward with an MPG is already exists feature on Heidenhain cnc controller. IT IS SO HANDY FEATURE especially when you start a program and you don't want to hit something.
mryoutuser Im a Heidenhain user. What's the feature you're talking about so I can test it?
Thanks for the great video! That manual tapping cycle would be super useful for picking up and chasing threads on a CNC lathe. Hopefully my turning center has this functionality.
Hallo from Germany...
I Wish there was a german Channel like this one.
Good work...
That tapping cycle is a great find, cant wait to try it!!! I have the same control on my M50 H Mits, Thanks!!
Wow, that manual tapping is amazing, never knew a cnc could do that. I was stunned when I can slow down the feed rate during tapping at Siemens 840d, but the is a whole different animal! Need some time to figure out what can be benefit from this future!
That tapping sequence is really cool!
Great video.
Hi, I have a Feeler / Fair Freind FV1600 with Meldas 64 control, this tapping does not work, you can set it in mdi but as soon as you change to jog or hand-wheel mode it loses the setting...
They must have disabled this in other controls. This is the only machine I have ever run that can do this. I only learned it by accident when I stopped the machine with feed hold in the middle of tapping some holes (Broke the tap) and jogged back the Z axis without hitting reset and noticed it was still synced to the Z axis. Than I tried what I show in this video and it worked. I don't think the designers of this control intended for this. It could be a safety issue and was disabled. If you could imagine someone grabbing hold or getting gloves or clothing on the tool holder and jogging the Z back and the spindle turns. That could be bad.
Cool track on the bridgeport, thanks!
I tried the jog tapping on a haas vf6 today but I couldn't get it to work
My Mitsubishi horizontal mill is the only machine I have ever been able to do this on. Very unusual for a machine to do this.
Watched AVE's video too about chatter. I wonder if the two of you are on to something new. I want to see that integrated into some CAM packages.
It already is in CAM softwares, like for example SolidCAM automatically can finish a pockets corners, floor and walls without touching the others and thus you get no tool chatter in those situations.
Not to mention that SolidCAM's iMachining just wipes all the other CAM softwares under the table in ease of use and money savings.
Some cnc-controllers support this, although its mostly a software-option you have to pay for. For the Heidenhain controller it's called ACC (Active Chatter Control)
man that variable rpm would be realllllly nice on the 5 axis pocket nc, could probably have an rpm change built into the gcode, but it would be nice if fusion did it. perhaps some post processor investigation is in my future. So far the best roughing speed is 40 ipm with 0.040 axial, 0.010 radial with a ticn coated 1/8 endmill at an inch of stickout and 10k rpm. I need the inch of stickout to clear the collet that holds the stock(er32). Ideally I would use a 1in stickout reduced shank 1/8in endmill with less than 1/8 axial cut.
edit: looked and of course harvey tool has a .187 axial extended reach line up for 1/8in endmills
sure do appreciate your awesome videos, and finally a true cnc PRO on youtube: like the CNC version of Jody/weldingtipsandtricks or Adam Boothe Abom79/manual machine work.
Which Mitsubishi Meldas control is it? I'm currently looking at a high speed tapping centre that uses the Meldas m50 controller but there is barely any info on it.
My horizontal mill has a Meldas 520MH6 control. I like this control for the mill not so much for the lathe.
You might try this on you tm and tl Haas machines at home. I would be interistes to know if they are capable of doing this because we tap some 3/8 and 1/2 npt holes at work on our tm1. We have to run sevral taping cycles and incrimentaly increse the depth, clear the chip, run another deeper cycle and keep doing that till we hit the depth we want. I don't think we have ever tryed that with the tl1 because we just got it about 3 or 4 months ago but i do think it has ridgid taping. If you could try this on your Haas machines that would be fantastic and would really help me out!
Hi Guys. Ever wondered what is actually causing the chatter? This excellent video demonstrates that the chatter happens when the tool’s cutting face is up very close to the work. This increases from a short arc of the cutting interface when running along a straight to becoming obvious when in the corner, nearly a quarter of the cutting edge is in contact with the work. In this situation: chips are being drawn from the workpiece and driven between the cut edge and the cutter edge. This needs to flex the bit a little bit and this, combined with the sound of chips being squashed against a hard surface and pushed along {like dragging a steel table leg across a concrete floor} produces the screeching noise from which we recoil. This is Chatter.
There are a couple of ways to fix this.
1) Blow a constant stream of compressed air to clean out the cutter from any swarf, and
2) Wash the cutting interface with a stream of cutting fluid ...
so that this effect is minimised. You don’t get chatter on a CNC machine running optimally with flood irrigation.
What was demonstrated was variable frequency chatter. Sorry, all you are doing is trying to burn out the motor with the jogging.
hello how about very good videos, how can you synchronize the spindle with the jog. greetings from Chile.
This is not something every machine will do. I found this out by accident that this machine would do this.
Neat trick with the corner milling, never seen that before.
Great tips. The tapping feature is very cool.
Those current surges will cause your motor and your switch to heat up. I prefer Joe Pieczynski's method of raising the quill, moving to the corner, and plunging the end mill using the quill.
What about using G4 in a corner and leave the endmill there a couple of seconds to reduce vibration (chatter)?
On a CNC machine what I have found that works the best is to actually not stay in the corner any longer than necessary. I have actually programmed arcs in corners and increased the feed at the arc to get in and out of the corner faster. On some older CNC machines if you have a sharp corner defined by just two lines it can actually make the machine dwell for a instant in the corner because the control is moving to the lines intersection. This will increase the chatter in the corner. Its better to do mutable plunges working out to the corner than mill around the profile. As I said in the video I use two separate tools. One to plunge that I grind all the flutes (Or use a reduced shank sort cut length tool) but the last 1/4". And a tool to finish the walls and floor. Some times I take mutable finish passes on the wall at different levels down also. I generally finish the floor first standing off the wall than finish the walls if the pocket has a floor.
Yeah, "self excited" resonance does not tend to go away with time, and can in fact self reinforce in some instances.
Plus the chatter marks from vibration will be in a 'metal off' condition so returning or staying in the corner won't remove them.
Refarding the endmill chatter in the corner I would choose a 2 flute, 4 flutes in aluminum will usually be more prone to chatter.Myself, I have actually better luck with high helix flutes than low helix in certain instances. If you can turn the rpm down low enough and feed it accordingly you can probably get a really decent finish without pulsing the rpm. Very low rpm allows a nice finish on a variety of sensitive operations, like countersinking for example. In fact, where it's possibly to turn the tool or material (in a lathe) by hand you can get excellent finishes with certain tool and parts that would otherwise make you pull your hair from frustration. Sometimes a slightly but evenly worn tool (less clearance angle) will cut nicer in corners. The cutting edge doesn't try to dig in as much. Less clearance angle and less rake are not as prone to chatter in many scenarios, of course they may not perform as well in other aspects.
This is awesome what a cool trick
Good video Peter very interesting.
Usually when I’m borderline touching the corner I would pull the quill up raising the tool. And then move over so the cutter is slightly over the radius and then just plunge down and feed away
I'm not sure on the Meldas but on Fanuc controls it uses a feature called swap axis..the spindle becomes the x axis during a tapping cycle and acts like a feed axis which is fully synchronized to the other feed axis. Until this is cancelled with a G80 it will act like the Meldas above.
That's probably so you can use a 90 deg. head. So you can jog a tap with the handle jog like I did in this video? I have never tried it on the Fanuc control. On the bridge mill we have here you just rotate the work plane say into the YZ than the X becomes the Z axis. With all the abilities of a normal Z axis tapping canned cycles exc. In fact it can be at any angle depending how you rotate the work plane like a 5axis machine. We do a job with a 90 deg. head at a 45 deg. angle to the X axis. Thanks for the Info.
I think but not 100% sure that it's to get around having to install another axis on the software side so you can do a tap cycle with a 4 axis control that doesn't normally have a software synchronized spindle which would of needed a much more expensive 5 axis controller. For example the Fanuc 18 had a max of 4 programmable axis back in the 1990's so the only way to synch the spindle for tapping was to swap another axis via software on the fly (swap axis feature). The MTB would install the servo type spindle motor which was +/- 10v analogue control with an encoder on the spindle and use the swap axis to activate it as a synchronized axis only during tapping when the x axis wasn't needed. All about keeping build the costs down for the MTB :-)
Thanks
Another great and informative video :D . Just for the record , i tried this spindle speed variation ona cnc lathe (but just manually , it does not have a cycle for it) it helps , but it's not the best solution . Turns out i got a lot better result using a little(20-30%) higher feedrate and 10% lower cutting speed .
I agree its better to get the feed and speed correct. But in rare instances I have resorted to the speed override buttons and it does work but its my last resort. I don't like to have to be at the control 100% of the time with my finger on feed hold or the override buttons.
I think the same way , i always like to program it correctly and let it run 100% of the programmed values .
Cool MDI tapping technique! Thanks for your videos - are you also on Instagram? 🙃🙃🙃
I do have a instagram as Peter L Stanton but I have never done anything with it. I'm not that tech savvy I am still learning about all this social media stuff. I need some help with that.
You probably found a glitch in the MELDAS 520 control software.
Not a glitch. As long as the sync is active, it will synch the spindle position vs. Z-axis position (or whatever you are using as the tool axis). Standard feature on pretty much any machine that can do rigid tapping cycles.
Meldas 65 does the samething
is like SSV in a Haas lathe ?
Omg i will try this manual taping on fanuc asap :D
Does it work?
Great video thanks for the tip
Now I want to try that on my Daewoo lathe with the Meldas control
Your just slowing the rpm when doing the pulsing. It needs to be slower because the angle of engagement increases.
Yes the variation in the speed kills the vibration/chatter. On a CNC machine you can vary the spindle speed override its sort of like doing that but manually.
@@EdgePrecision I was saying it's slightly different because your killing the harmonics when doing this in a cnc lathe and not with this because a slower rpm would cut the corner correctly(vibration occurs per flute at higher rpm). I love your videos btw. I can see why you bought that mazak.
thanks for another neat tip.
Hello Sir
I'd like to thank you very much for sharing this techniques
I like all and specially the manual jog threading.
I really appreciate this video
thanks a lot
I think our old Mori’s can do the same.
Tell them to kick that a.c. on! Lol. I bet they're stingy with the a.c. in the shop area, but have it ripping cold in the office area.
When you see variable helix and stagger relief end mills for sale that is the purpose of them. To disturb the harmonics of chatter that result from excess radial engagement. Obvs with modern tool path we can govern consistent engagement to an amount that works well.
Yes the idea is to reduce chatter by disturbing the harmonics like you say. This does work and it can be worth paying for. It sometimes can be hard to measure the diameter of the tool. You have to make sure which flutes you are measuring.
Edge Precision
I can't remember the last time I measured diameter with a touch probe. I've used an optical offline setter, laser in machine probe, and of course the old cut, measure, set, recut. The JV squad manages to break touch probes with such regularity that every place I've worked just moves on away from them :D
Similarly I never really messed around with the variable flute/helix endmills. It was just simpler to "git gud" with constrained engagement toolpath.
I like having the old school knowledge and in my mental toolbox to fold in as a bit of spice with state of the art recipes.
Tapping trick is so cool
I will try te tapping on the haas tomorrow. Be sweet if it works...
Very cool ability!
They should all do this..thats bad ass bud.
Nothing worse than safety devices that do nothing more than get in the way. Damn clipboard warriors.
Why not make a macro program and do a pecking G84 cycle? =D
Mikie B you could do that. I was just trying to demonstrate doing it manually.
i'll keep them up my sleeve.
Chatter is a "harmonic" and when you have "two-phase" AC current (if its not "3-phase" its technically "single-phase" since all AC is "phased" and only a single phase exists between the two "legs" of non-3 phase current) operating machines made for 3-phase current which is "one third smoother" in power delivery, its pretty easy to have "chatter" in certain "speeds" where the number of cutters, AC frequency and "two phases" all end up "in synch" to set up a "harmonic". If there is an even number of cutters you don't want "2-phase" current because its easy for 60-cycle current and particular current ran through a "converter" to end up being "in phase" with the even number of cutters. As for cutters "in contact" the MORE cutters "in contact" the BETTER for single-phase AC and the harder it is to produce "chatter". Simple drill bits have only two cutters and work well with all types of AC and DC current because there is a CONSTANT LOAD on the CUTTERS. Chatter occurs when loads and/or power reach the tool "intermittently" and "in phase" such that a load and a lack of power "overlap".
Badass
stupid...yall are sending ppl in tge wrong direction
Matt Dostou Maybe you can educate me. What was stupid or giving wrong direction? Tell me if you can. I was just showing a few things I have actually done in the past that were a help to me. I'm not suggesting they are the end all or the best way of doing things. What have you done? How is it better? Tell me if you can.