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  1. #101
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    Quote Originally Posted by arie2003 View Post
    Hi camminc,

    thank you for your sharing. I believe that you are correct because I ever see the effect of dynamic analysis to improve surface quality even I never do it by myself.
    I think this is an misunderstanding in this thread. The initial question is about HSM. HSM is a complex system. This include machine, CAD/CAM software, tooling system and programmer. Your point if view is only in tooling system area. Other people point of view specially is machine area. I haven't see people talk about CAD/CAM software and programmer capability in this thread.
    Base on my experience in HSM, we must know the machine characteristic first. Must understand about spindle power, controller capability, data storage capability, data transfer, servo response, PLC response, etc.
    After that we can select suitable tool and cutting method. The key point is programmer, because he is the person who will combine all those factor.
    I always said to my colleague that HSM method is similar with F1 racing for easy understanding. We can see analogy between machine and F1 car, tooling system and F1 tyres, programmed toolpath and race circuit, programmer and F1 driver.
    F1 team must aware about all factor and F1 driver must have ability to combine all those factor. You can imagine if the team have good tyres but their car is unstable, are they can win the race?
    Or, they have good car, tyres but the driver don't understand the circuit, I think they will fail also.
    The winner is a team that have good car, good tyres, understand the circuit very well and have driver who can drive it very well.
    This is similar with HSM. The people who can combine all those things can get big advantages of HSM.
    I have experience when making one mould. This is one year machine (installed at May 2008) with latest and highest controller of FANUC. By using same machine, I try to change cutting method, tool, cooling method and change some machine parameter related acceleration and deceleration, and I can improve machine productivity 100%.
    Once more, HSM is complex system, we can't see from one point of view. Everybody who write in this thread is correct but they are see from different point of view.

    This is just my opinion. Sorry for my bad english.


    Indoeneasia, oh yea you guys are on the cutting edge, How are those brand new MX100 controlss you just got?
    Give us a break

    Bluesnman
    PS. Only a hack would mess with the ACK/DACK Parrameters



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    Quote Originally Posted by Bluesman View Post
    Indoeneasia, oh yea you guys are on the cutting edge, How are those brand new MX100 controlss you just got?
    Give us a break

    Bluesnman
    PS. Only a hack would mess with the ACK/DACK Parrameters
    Good thing you don't have to work around here. The Hacks are wall to wall, but I enjoy the amusement. Seems that we are running out of real machinists, I wonder why? Maybe there are too many Annoying Hacks and the Real Machinists are having heart attacks when watching them pretend to know what they are doing, LOL.

    Toby D.
    "Imagination and Memory are but one thing, but for divers considerations have divers names"
    Schwarzwald

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

    www.refractotech.com


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    Default What is high speed machining?

    Well, it looks like all you guys and gals have a very good knowledge of machining, rather it be turning, milling, drilling, sfm, ipm, chip load, etc. The basic condition of HSM is many. The way to maximize HSM is to take all these conditions and measure it at the tool tip, for at the tool tip it shows all the dynamic characterizations to enable a maximized, chatter free cut. I measures al the dynamic’s of the machine tool assemblies to maximize at the tool tip.

    You can't do an impact at the machine structure or spindle or another place, because all dynamics come down to the tool tip when you cut. That would only tell you their dynamic’s which is what is call “Modal Analysis”. That is the key thing to remember. The only way to measure what is going to occur in the cut is at the tool tip. Measure what is happening at the tip of the tool contacting the part.

    Basically the programmer creates the program, the operator sets up the machine and tools and cuts. Programmers can change parameters, slow it down, less of a cut, plunge, etc. but it all ends up at the tool tip. That is what is being heard, seen and noticed.

    Controllers, feed, chip load, depth of cut, five axis or 3. When it cuts you can hear how it cuts, if it is in the sweet spot. The faster the rpm the more pronounced, the deeper the cut the more pronounced. To assure it is maximized one must take an impact test prior upon the cutter tip to see what it really requires, all dynamic information from the machine tool, is utilized and estimated for best chatter free rpm and estimated depth of cut pertaining to radial engagement of the cutter and depth of cut, nomenclature of the cutter. Stability lobe diagrams are produced showing the areas of maximum penetration, then calculate feed rate / chip load. They don't care what cutter, programming, cutter nomenclature, it only shows what is. You can modify those entities to maximize. Cutter nomenclature alone can change the depth, finish and chip removal after you once determine the frequencies, spindle speed, to run.

    Once this is achieved, document:

    Holder
    Cutter
    Stickout
    All called "Stack up"
    Use this "Stack up" each time and the same results will occur unless the machine tool dynamics change, which they do.

    Many times I have been in a shop and can hear the cut, I can tell if it is stable or not.
    A true HSM cut will hum with a minimal amount of frequency change. It will maintain a constant frequency when it is stable. A lower frequency means a deep cut but must be constant. A up and down hum is the cutter jumping in and out being unstable.

    Audio frequency is one way to detect, impacting is the other way to get it close.

    Once you find a sweet spot cut in the program the cutter assembly must always be setup in that "Stack Up". Same holder, same cutter, same stick out, same rpm, same ipr, and same path. If you change anyone of these the dynamics change and it is lost.



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    Camminc

    You are right we at Cessna have done some work on stability lobe and dynamics.We have not yet moved to complete HSM. we are evaluating. what are the typical dimensions of a pocket if we want to differentiate it as a small pocket and a large pocket in HSM



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    Smile need to find out about impacting and the beginning of the discussion

    [QUOTE=camminc;569820]Little Story: I need to find out about impacting and how the discussion started and how do I get to it or search it out. I assume you are talking about the dynamics taking place with the resonance etc from the impacts of the cutter teeth. let me know how to find out about it please. Thanks Jeff



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    [quote=JCMills;767012]
    Quote Originally Posted by camminc View Post
    Little Story: I need to find out about impacting and how the discussion started and how do I get to it or search it out. I assume you are talking about the dynamics taking place with the resonance etc from the impacts of the cutter teeth. let me know how to find out about it please. Thanks Jeff
    Hi. It seems that in our industry that programmers are being put in charge of HSM in shops when programmers really are not qualified to do so. It should be a group, a programmer, a tooling specialist, a couple of actual good machinist, a manager and a supervisor to listen. As I am seeing programmers are being put solely in charge of programming, tooling, tooling methods being used such as cutter selection, etc. When programmers really don't know jack about tooling, they need to stay on their computer and only come out when we request it, the machinist running the part and the tooling specialist deciding what tools need to be used. Then the programmer needs to listen to us and simply make the adjustments we tell him or her to and then log that dynamic information into a tool log of some sort, the tooling specialist will also log the dynamic information into a general dynamic characterization database for retrieval by all subject of the committee, managers, supervisors, machine operators, tool crib set up personnel, presetting and programming. Programmers have a tool catalog that is not compatible, most of the time with this dynamic characterization database, so the programmers need to be trained in using it so we will all use the same information and be on the right level, together, as a team. Programmers tend to want to make their own rules and regulations to adhere to them which makes team work of all others difficult and other wise impossible to do. The unit should have a head of meeting who has enough knowledge in data collection to be able to make the correct decision of how this is to all be obtained and used, in the best interest of all inolved, not just for the programmers who are only 1-10th of the resolving group. The tooling specialist will provide special cutters to the machinist of the machine and together come to a depth of cut, width of cut, feed rate, etc and relay that information into a general dynamic characterization database, then the programmer shall view this data and enter given tooling parameters into the program with quotes – notes at these sections sharing this information with the machinist and tool specialist so we all know :where, when and how” the tool path is being used so we can watch / our input, take reading, frequency data, etc.



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    Default hsm

    The programmer has many things to do, they cannot possibly cover all areas. The programmer is to take care of the programming of the paths and dimensions and general depths of cut and radial and actual parameters using sfm medium parameters.

    The machinist will run the program and log all improper sections of the program and get with the tooling specialist to correct it, together.

    The tooling specialist will then decide to do some impact testing or audio chatter detection and balancing on a cutter assembly to provide the dynamic information required and give input of tooling changes that will allow proper MRR. The balance of the tooling will be compared to the forces of the cut to obtain a threshold that is acceptable along with the frequency of the assembly to derive the best depth of cut pertaining to the FRF he or she will generates of the material being machined. The tool specialist will also decide what type of cutter nomenclature along with the machinist and programmer of what is really required. Coatings, cutting tool material, whether it be carbide, carbide grades, cod, pad, diamond coatings, Tin, Tic, Tail, pad, high speed steel coated, cutter geometry, holders, shrink fit, collet holder, set screw, milling chuck, dead metal intigration, number of flutes, flute geometry, etc. If special cutters need to be required that tool design can input on then tool design works with the tooling specialist and tooling vendor. The tooling vendor knows what they have in stock to communicate with the tool specialist so the tooling specialist and obtain what he wants from them, the vendor for free will have it drawn up for the tooling specialist, machinist and programmer to review, while management and supervision listen and make the other decision as to money, long term capability of the tooling. The vendor can provide input of what types of their product we can coat with what we want due to cobalt, grade and miniature structure of the carbide, can, pcs, diamond,etc. They have the molds for what the inserts will look like which decides how the cutter will look, etc.

    The company tooling designer will work with the tooling vendor designer and tool specialist and create the cutter or cutter and assembly.

    The programmers is then taken out of the equation so as not to be the funneled weak area and we then all work together to maximized the operation.

    We also need structural personnel to input the dynamics of the part being machined and tooling personnel to input how to hold the part and support any weak area's that might chatter.



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    [quote=JCMills;767012]
    Quote Originally Posted by camminc View Post
    Little Story: I need to find out about impacting and how the discussion started and how do I get to it or search it out. I assume you are talking about the dynamics taking place with the resonance etc from the impacts of the cutter teeth. let me know how to find out about it please. Thanks Jeff
    Hi Jeff: Start with this I guess. Scott Smith and Tom Delio trained me, here are some links. If you want to talk to them and find out about classes just email me at rharper@cammhsm.com

    http://www.coe.uncc.edu/newsletter/n...h-honored.html

    http://techcon.ncms.org/00fall/prese...th-Chatter.pdf

    http://www.mfg-labs.com/mfg-labs/exampleparts.htm

    http://www.mfg-labs.com/mfg-labs/Design/

    http://mfg-labs.com/ (I developed CHiPS)

    http://www.coe.org/Collaboration/Dis...1/Default.aspx

    http://blueswarf.weebly.com/tool-dashboardstrade.html

    Thanks, Randy



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    [quote=JCMills;767012]
    Quote Originally Posted by camminc View Post
    Little Story: I need to find out about impacting and how the discussion started and how do I get to it or search it out. I assume you are talking about the dynamics taking place with the resonance etc from the impacts of the cutter teeth. let me know how to find out about it please. Thanks Jeff
    Jeff: To answer your question about how this thread got started: This is going to be a long one.

    This discussion started somewhere around 4-2003 with a couple of long time forum guys named Hardmill and Scott-bob. Hardmill is I guess some kind of programmer and Scott-bob races desert cars and is some kind of CNC process engineer. Neither one of them probably never had any practical experience with actual HS machines, tooling, etc. So, I rebutted their ridiculous beliefs for about 2 years and then moved on. Their ideas and methods were dinasourish, unpractical and certainly inexperienced.

    I, Camminc, on the other hand am a real time user of impact testing equipment on the shop floor in a high speed manufacturing environment. I personally do shrink fit with induction heating and balancing of tool assemblies dynamically and static. (Single plane and Two plane). I have been a tool and cutter grinder for over 20 years and taken care of tool cribs, inventory and control, presetting for milling machines, purchase tooling and eventually design and participate in HSM. I have done nothing but tooling all my career, on the shop floor, cutting tools for the past 30 years. I don't talk about knowing programming or race cars because I don't know much about them, but I do know tools.

    I joined the SME in 1998, about 25 years into manufacturing, wanting to learn about HSM, shrink, balance and chatter. I went to Westec to hear what Boeing had to say about it all, at a HSM clinic I paid $400 to go to, my own money. The company I was working for was venturing into it and I was the fall guy if anything went wrong, so I do what I do, learn. They did reimburse me when they found out I went on my own. I made good progress as time went by and the balance guru at Hoffmann noticed my enthusiasm and asked if I wanted to speak at some SME HSM Clinics about the advanced methods I was using and learning, since I was going into uncharted territory, he was watching me. At the time he was head chairman of the HSM clinics for the SME.

    Well, anyway, I traveled for about a year doing the SME circuit for the company I worked for, meeting Boeing people and many other wonderfully, knowledgeable people from all kinds of companies doing HSM at the time. I went with Harold Cook (Patent Holder Shrinker) to Boeing Everett, Seattle, Portland, Wichita, Ingersoll in Illinois, Kennametal plus a few other well known companies doing HSM at the time. I ended up with a couple of patents being filed by my employer on balancing for HSM tooling, wrote 3 technical articles for Mold Making Technology Magazine while there, 5 now, involved in a SME tour of our plant in CA, met and made friends with Harold Cook, patent holder of the Shrinker, I was trained by Dr. Scott Smith and Dr. Thomas S. Delio of MLI in dynamics, impact testing, dynamic characterization, chatter detection and correction and audio chatter recognition. Dr. Delio developed the Harmonizer. Dr. Delio also headed up CRAC, Chatter Recognition and Control at the controller, Makino, etc. Now things are called Blueswarf, must be Kennametal has taken over allot of it from Dr. Delio. Tom and I still see each other and are good friends.

    Anyway, just so you know my back ground, I couldn't take all the bean dip that Hardmill and Scott-bob were dishing out on this forum and decided to set it straight. It really doesn't matter if any of the readers believe what I said, because it is what it is and I have lived it. Unlike, Hardmill and Scott-bob, talking about something they really don't know anything about.

    So, that is how this thread got started. I would pop in and out now and then but haven't been around for a long while now. I have other idea’s going on now.

    The end deal is, you have to have sections of experts in specific fields to do HSM, as I would think is probably true with most any involved process. No one man is an Island, only one of many. A programmer cannot know everything I know about tooling, chatter, frequencies, flexibility, etc just like I cannot know diddle about programming, and I don't care to know programming and don't claim to. It would be ridiculous to even pretend so.

    As time goes by, I mean as the years go by, I find out more and more that this is true. Programmers are the worst about thinking they know cutting tools and processes and it really messes things up. They think because they can create a program that they know tooling too? That is rediculous. I have talked to hundreds of programmers and dealt with many engineers, managers, supervisors, lead men, that say they know about HSM, chatter etc. But I can tell you, most don't have a clue what I am talking about when I get down into it and then they defensive towards me beause of it. Myself, I don't know programming, supervision, managing, engineering and I certainly don't try to make anyone think I do. Heck even tool salesmen don’t know about chatter and dynamics. I have not met any yet that really understood what I was talking about except those that have had that training, and they are few and far between. Sales people are not trained in dynamics, it would be to costly, so they have specialist, phd's, etc. Those are the guys to talk to.

    Here is an example: I worked for a large company running a CNC lathe. To make a long story short, the tooling sales person was selling the company some dampened bars to prevent chatter on a I.D. Threading process I was doing. The head of tooling in the shop I was working in came by and asked where to cut the bar off so it would fit in the machine. Well, the bottom line was, it is a dampened bar. You can’t just cut it in half and expect it to work. He was a former CNC lathe or Milling guy, new a little programming and didn't know diddle about cutting tools or dynamics, but they made him the head of tooling for some reason.

    Well they didn’t listen to anything I said, so they cut it in half, clamped it in the dampened area of the bar and the chatter got worse. They did this on two machines. I tried to tell them but they would not listen nor did they understand at all. Again, the programmers, the head tooling guy, the manager and the supervisor did not have the training to know this. The worst part about all this was that the tooling salesman didn’t even know that we can’t do this to that bar. I ended up having to get a specialist from the tooling company, and this company is a worldwide seller of cutting tools to thousands of shops. I couldn’t believe what I was seeing.

    Finally they sent a specialist regional representative in and I explained to him what was going on. He had no choice but to agree with me and get rid of that bar and go back to the one I wanted in the first place. This was $6,000 later in bars, they had 4 of them, not to say the money wasted in scrap parts due to the chatter marks on a threaded part. They fired the sales person, I guess he became the fall guy on that one. Needless to say at our shop, programming, tooling, manager and supervisor didn’t thank me, didn't shake my hand, pat on the back, nothing. They just covered it up and acted like nothing ever happened. Of course in their minds I was the bad guy here, funny how that works.

    What they didn't know about Dampened bars: The dampened bar in this case was 22 inches long and 2-1/2” in diameter. This as are all sampened bars, are meant to be long for long reaches. 4-10 times diameter ratio. This style bar has a mark about 7 inches from the front of it, etched line, that means 'Do not to clamp in this area", the dampener inside is in this area.

    It has another line etched more towards the back end at about 16” from the front. That mark is to tell you "Not to cut this bar any shorter than this line", because it is a tuned bar and requires the mass to dampener ratio to be held in order to dampen. Freqeuncy stuff. Needless to say, they cut the bar at 15inches, 1" below the mark and then we had to clamp the bar in the dampened area where it said not to. $2,000 down the drain for that bar. Of course these rules don't come with the bar, you have to know about it. or ask for a drawing on it, or do what they did, rely on the tooling vendor. I don't rely on any tooling vendor unless I drill them first.

    The thinking of these guys in my shop was that they were using integrated dampened bars on other machines and they worked great, so this will work even better. But the fact was that they couldn’t modify those dampened bars on the other machines because they were integrated bars. They were one piece assemblies with a quick change interface on it so it could not be modified. I don’t think to this day that they understand it all. What they thought would be awesome turned out to be deadly.



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    Quote Originally Posted by Mohan View Post
    Camminc

    You are right we at Cessna have done some work on stability lobe and dynamics.We have not yet moved to complete HSM. we are evaluating. what are the typical dimensions of a pocket if we want to differentiate it as a small pocket and a large pocket in HSM
    Hi Mohan: Ya, I think you guys up there at Cessna Kansas purchased a MetalMax system. I am not involved with whom puchases MetalMax or Blueswarf but I remember hearing somewhere about it. Good deal dude.



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    Yup we have the software and apparatus but right now we are not doing much on this...



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    Quote Originally Posted by camminc View Post
    I have no idea what you mean by a cart and a horse? Machining has nothing to do with a cart and a horse? This is the kind of antiquated stuff I am talking about, spend all kinds of money replacing controllers on CNC machines because one guy thinks that is what will solve all problems. What will they do when they run into chatter, which will happen. The controllers won't solve that problem unless it can tell what frequency the chatter is at and then adjust RPM, which there is a product out there that will do that as well. But that is another story.

    I have been watching this type of attitude for years, it's disturbing how companies will send thousands to millions of dollars on a machine tool / programming software and elaborate computer stations but they pucker up when it comes to supporting / protecting / maximizing them with dynamic equipment. For a 10th of the money of one machine and it can be used plant wide - they just don't seem to be able to change, they just keep using the same old methods and ways of thinking while companies that do take the leap prosper and take away there business. It's mind boggling to watch. This equipment will even do modal analysis of a machine tool to maintance it, but that again is another story.
    Hi Randy,

    I am a newbie on this site. But gauging on your description of the Audio Chatter software process. Correct me if I am wrong, Chatter is a form of resonance of the machining process? Then doing an audio sample, do the software (a DFT Digital Fourier Transform) that finds the resonant points on the process (Machine + operating condition for a given work) then you can pick a different RPM that is significantly far away from those resonant peaks? Did I describe this correctly?



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What is high speed machining

What is high speed machining