What is high speed machining

[hardmill]

Welcome to the forum.
Hard and High speed machining is primarily about controlled
Speeds(sfm) and feeds(ipt),toolpaths and machine controls,
good rigid setups and good balanced holders(0-.0002 tir).
All depending on the material your machining of course. And again glad to have you here.
PEACE

[Scrit]

So in that case is it applicable to plastics and composites? Especially as for best finish quality we generally have to rough to +0.5mm then do a full depth finsh cut.

[turmite]

Hi hardmill. This is my first post here but this is an area I am interested in. I machine wood and am interested if hsm is applicable to the wood arena. My current machine will not do it but I plan to build a product specific machine this fall and winter which will be both rigid enough and have enough hp.

turmite

if you want to see what I make go to www.turnercustoms.com

[camminc]

Boy, I tell you, I get really irritated with Hardmill's answers on HSM. All about controllers, tool paths, feedrate, light cuts, fast feedrate stuff. Hardmill, you need to get over all this. All that stuff you talk about means nothing if your running a cutter at the wrong rpm and the only way to find that out is with dynamics. Machining wood, metal, plastic, graphite, etc.

Now, if you involve dynamics to find out the best rpm to run the cutter at then all those things you speak of help make it work better. Elimination of chatter. Think of it all as if your have built an awesome motor for a vehicle. You have high compression, high performance heads, valves, springs, fuel injection, computer controlled emissions, headers, high volume water pump, radical radiator but are using a distributor that is not giving the correct timing at specific rpm ranges. The motor will not run at it's full potential.

Now, put in a distributor that is tuned towards all the engine components. Timing is the key for spark, it has to be precise or else all other components mean nothing.

This is the same method used by dynamics. Race car mechanics us it and so does machining. You get the timing right - tooth pass frequency - and all the other components work together. Feedrate's are standard - chip load, sfm are standard but depth of cut and rpm are not and will increased simply by knowing the timing of the teeth engaging in the cut to harmonize - stability - correct rpm. The last operation done on a motor is setting up the timing curve. It is hooked up to a machine which dynamically tunes this curve to all the components of the motor thru all rpm ranges. The same method is used for machining, especially at high speeds. But there is no curve as with a motor, it is a specific rpm that runs best. The tool, holder, interface, spindle, structure of the machine tool are the components measured to find best rpm of cutter engagement for maximum depth of cut. Once rpm is established then determine SFM, chip load to material being machined.

You can have the best controller, the best toolpath, the best machine tool, but if you do not run it at the correct rpm it means nothing. Dynamics is the key. It doesn't matter what material your cutting to find a best rpm to increase MRR, the limiting factors are - HP,Torque, SFM, RPM of the machine tool. Once the dynamic rpm is found - can the machine tool provide the HP,Torque, SFM, RPM to maximize? Can the machine give the number 1x rpm to obtain maximization? The 1x rpm might be 40,000 rpm, possibly that rpm can not be reached, so the 2x would be 20,000 rpm but depth of cut will suffer, etc down the line to about a 4x multiplier. A simple database can calculate maximizing of the cutting operation for a machine tool - CHiPS, but it must have dynamic information input into it to maximize. That is by way of an impact test -such as the MetalMax System.

1: Impact Test - you will need to visit my site to view this method. At this time the video is down on the site so visit later again to see how it works. There is other information on the site to help understand what dynamics are such as a PowerPoint presentation, etc.
2: Impact test creates FRF (Frequency Response Function) correct rpm's
3: Impact test creates Stability lobe diagram - chart for viewing proper rpm's with depth of cut at those rpm's. There are many area's of rpm to run a cutter at, not just one. There are stability charts on the site to review. They give exact rpm's to depth of cut variables.
4: Impact test creates Flexibility reading - movement of the cutter as force is applied to determine maximum depth of cut

Boeing, Airbus, Lockheed Martin, TRW, Sikorski, Northrop, University of Florida, University of NC and many other organizations have used this method and many other organizations are teaching them around the world.

[bradleycnc]

camminc, how do you get thru the door with that big head of yours. You got somthin to sell or what. Had any buyers?

I hop the hardmill guy give you some feed back

Bradley

[camminc]

To bradleycnc - In 1997 at the age of 42, my world of thinking about machining went out the door and flew away. I was put in charge of tooling up a HSM, 16,000 rpm, hsk63A, 6 axis gantry for mold machining. I knew nothing about it, so I hit the forums, read all the machining magazines I could and asked as many questions as I could. I called people who wrote articles, papers, etc. Results, I went to shrink fit tool holders, worked with Harold Cook the patent holder many times, went to Boeing Portland, Seattle and Wichita with Harold to learn, he paid for the trip for me to learn. I then went to an American Hofmann tool holder balancer, 2 plane. Leaned enough about balancing that the company I worked for applied for two patents I had invented in balancing while I was there. I then ended up giving presentations at SME High Speed Machining clinics in the Los Angeles area, Chicago IMTS, Cincinnati IAMS institute, to give back what I had learned because I was so grateful to the SME for giving me this information. Then finally, all the pieces fell together when chatter remained the only other relevant factor in the shop limiting our machining operations, no matter how programmers programmed, controller type, tool path, cpu used, acceleration, etc. These all meant nothing without understanding dynamics, I was spinning my wheels without it. The company I worked for decided to hire a PHD at $125 and hr. to come in to the shop and train me in chatter detection / correction. Impact testing, audio chatter recognition, frequency response functions, stability lobes, flexibility readings, vibration analysis, dynamic database collection, modal analysis, all the things you probably don’t know nothing about. (The final step to increase the full potential of the machine tool). This was 6 years ago, I and the Doctor still work together, I learn from him each time we talk, we continue to work on projects and remain good friends. Well, the rest is what you read about in these forums. It is people like you that is the reason I go to these forums, to shake it up a bit, because from my experience that is what it takes to get most people who will not open their minds to new and useful ways, it is called antiquated ways of thinking. I have been there, I have done it and I have been successful at it. I have also written 5 articles on HSM in MoldMaking Technology - What have you accomplished lately in this field? I didn't have to be a rocket scientist to understand that to do an impact test on a machine tool was something very useful and amazing. When you can double your MRR in a matter of seconds by simply using RPM, it is easy to see, when you actually experience it. To go from an unstable cut to a stable cut by just using RPM is an experience. Have you ever used a stability lobe or FRF to increase MRR? I figured it would some day be noticed and taken under wing in the industry for it’s true purpose, that time is now arriving after 15 years of development. It provides problem solving answers quickly and avenues that those who never use it will never know. So, I suggest that you take a class in high speed machining, attend some seminars at the SME, ask questions, read machining magazines and forums, open your mind and then post your writings. Or you can just do what you do and I will go on preaching these advanced methods so others will know of them. It took countless hours of searching for the answers that I now have about HSM, I just got lucky and found the right people to share it with me. I offer this knowledge for free on these forums to anyone that wants to open their minds a little further. Thanks for your reply -bradleycnc. I certainly appreciate it, for those kinds of replies are why I do this kind of thing.

[ESjaavik]

@Camminc: Are you telling us that these factors does not matter:

controlled Speeds(sfm) and feeds(ipt),toolpaths and machine controls, good rigid setups and good balanced holders(0-.0002 tir). (Hardmill)

And that the only thing that matters is getting the RPM right?

Sorry, but you have to do a better job of explaining. To me it seems BradleyCNC has a point: You are trying to sell something. Well if you do that by putting down someone that has been contributing with a variety of information (Hardmill) in these forums, I don't think you serve your case well.

Please go back and read the first post in this thread. Then give us the answer. With your impressive experience that should be easy?

[Gunner]

Camminc's product is just a part of the entire HSM equation. Other parts such as machine control, torque, spindle speed, rigidity, balancing, coolant, tooling, etc can also be limiting factors in the equation. The product camminc endorses will help find optimum chatter free zones of operation with your current machines which will result in desirable improvements such as increased tool life, repeatability, and completed pieces at the end of the day. This may be good enough for some but not for those who really want to get into HSM. They will look for other big hitters such as the machine control and RPM, all of with can have huge impacts. You reach the ultimate when you put all the parts of the equation together. Then you are no longer guessing about getting better, you know you're there and there ain't no more.

[Gunner]

ESjaavik Please go back and read the first post in this thread. Then give us the answer. With your impressive experience that should be easy?

IAMS in Cinncinnati (now Tech Solve) has a definition that makes the most sense to me. It is " The manipulation of speed, feed, and depth of cut, to develope increased metal removal rates with lower cutting forces. This process, in turn, reduces or eliminates secondary work for an overall increase in productivity".

HSM does not necessarily mean higher speeds and lighter cuts. It means you optimize your operation by determining your depth of cut, RPM, and feedrate, based on data determined by the machines power rating and max rpm, cutter operation frequency, chip load, and a variety of other factors that can be plugged into your equation.

[ESjaavik]

@Gunner: Thanks!
That was easy to understand. You obviously realize that to explain something to the uninitiated like JohnM or me, then you need to start at the first step.

[camminc]

I agree. The way to do all this is by Impact testing, otherwise it is all a guess. It provides natural frequency, flexibility and stiffness of the cutter at it's tool tip, giving calculated best rpm which in turn gives highest doc that can be reached by that machine tool rpm using this dynamic information. Also providing FRF and stability charts to make educated decisions on rpm to maximize. A database is then used with set selectable multiple choice parameters of a cutting tool for material specific power requirements, max speed of machine spindle, natural frequency, flexability, stiffness, number of teeth, stick out of cutter, gage length of cutter, flutes, chip loads, holder, interface, feedrates. Spread sheets do not work, it has to be a database. There are a multitude of other information that can be tracked in a database to help programmers maximize. It all sounds difficult but it really is not. Programmers, tool crib, presetting use this database to setup this cutter dynamically, to maximize the operation. Once the database is set of a cutter, all the programmer, tool crib or presetting needs to do is view the information they need to set up the cutter, in one easy step. Then controllers work with the cutting tool instead of against it.