What is high speed machining

[Klox]

Hardmill, Jimmy would you two gentleman please tell a guy like me what is high speed machining exactly? I'm only used to SLOW (edm)speed machining

Klox

[hardmill]

Originally posted by hardmill As simply as i can put it hsm is taking smaller, lighter cuts at high feedrates. Special tools are required as well as the machines ability to take in the code. Machine also needs to be equipped with an acceleration & deceleration options so it will slow down in tight corners. It doe'nt always require all those variables but then you may lose on accuracy, tool life, etc. An older machine could feasible be used and still gain positive results. Hard machining requires similiar variables.

Generally you start at about 600sfm depending on matl., mach.,
toolpath ,tooling, etc...

[Klox]

Where would one take the high speed machining route instead of doing things the "normal" way.
Is it when there is a lot of roughing ou to do?
You can actually move this whole thread and attach it to the one JohnM started.

Klox

[JIMMY]

I would say that high speed machining would always be the way to go unless you have soom super tool that can take massive amounts of material off. If you have the right feeds and speeds you can realy take material off. like HardMill said, you should have a machine that can handle it. You would be amazed to see how fast the removel of material is with high speed machining.


JIMMY

[camminc]

HSM is an acronym, it is a word used in the industry that has stuck in our heads. What it should be called is Maximized. There is no set standard for HSM, that is why we all are asking this question over and over again and no one can give us a solid answer. The anwser is - HSM has nothing to do with lighter cuts and higher feed rates that a machine might offer, special cutters, controllers, etc. It has to do with dynamics. You can purchase a 5 million dollar machine with all the fancy stuff but you can’t make it sing without dynamics, period. See MoldMaking Technology in June for Chatter Myths by Randy Harper also see http://members.cox.net/camminc/

[BIG AL]

SWEET, thank you camminc and Randy Harper. Nothing like a little truth in adverticeing!

[Scott_bob]

I disagree with camminc!

HSM is a blending of multiple technologies, not just one that is claims to be the cure all.
Maximized, yes. Motion control begins in the brain of a CNC machine. G-code is an input to the machining center, motion is the output. The best inputs cannot produce good output if the CPU is crap. If we improve the central nervous system of a CNC machine by installing an Active Dynamic Feed Compensation system and ignore the brain or CPU, then we have spent money on the wrong technology 1st.

Active Dynamic Feed Compensation (ADFC) is good technology for a CNC with good performance motion control. Also, ADFC is limited to processes that can be detected by vibration and acoustic measurement. Mold machining where HSM benefits are the greatest, ADFC benefits are marginal because during finishing, the vibration and acoustic methods of monitoring are not sensitive enough yet, or the performance signature cannot be identified cost effectively . Unless I am misinformed, the vibration or acoustic signature must be taught to the system before compensation dynamics can offer benefit. Molds are never production items where a process can be monitored and tuned to optimum performance. Who has time for this? In a production run, that’s a different story…

I maintain that in order to take advantage of maximized productivity in CNC machining, you have to systematically address the issues. Make a list of the contributing factors, depending on your CNC, at the top of your list of variables will be the most significant factor. Our’s is the Fadal control, contributing by far the most, in poor performance.

Camminc:
“The answer is - HSM has nothing to do with lighter cuts and higher feed rates that a machine might offer, special cutters, controllers, etc”

HSM cannot succeed without these “factors” that camminc said: “The answer is - HSM has nothing to do with”…

Let’s not replace one myth, with another…

[hardmill]

Agreed. There are many things to be considered,
Your going to have to throw all variables into the mix.
When one decides to go this route all these factors need
to be addressed and reseached.
Thanks for your replies gentlemen.

PEACE

[camminc]

To Scott_bob: Hi, this is Randy. Let me ask you a question? Have you ever done an impact test on a machine tool cutter assembly (Stackup) and then diagnosed a FRF or Stability Chart that was produced by that process to use for the machining process, in conventional or HSM?

I have done it hundreds of times, I am on the floor right along with the machine operator doing real time measurements, improving the machining operation. I have worked with many different machines, conventional and HSM, all kinds of controllers, all kinds of cpu’s, all kinds of cutters, etc. It doesn’t matter to me what machine tool is used I still get the results of the machine dynamics in the end at the end of the tool tip because that is where it all shows up, period. I agree that it is a good idea to use the best controllers, cpu’s etc that one can purchase but it still doesn’t tell you what RPM to run the cutter at to maximize. Lets face it, no company is using the same controllers and cpu’s on their machines and that certainly does not tell the operator or programmer what RPM to use.

It takes only a few minutes to do an Impact Test and get the results, it is not time consuming as you might feel. It is just as useful on a single mold as it is for production runs. If your running the wrong RPM then the depth of cut will suffer along with finish and MRR. I am not sure what your statement of “the vibration or acoustic signature must be taught to the system before compensation dynamics can offer benefit” means? The dynamic signature measured at the tool tip is a direct result of the overall machine tool system, there is no being taught applied, it is what it is and it can be measured to tell one what RPM and Depth of cut to take in a matter of seconds.

The statement “Molds are never production items where a process can be monitored and tuned to optimum performance. Who has time for this? In a production run, that’s a different story” That is an assumed statement which is not true, if you have ever done an Impact Test or an Audio Chatter Recognition reading then you would not be saying that. This is the kind of attitude that I have dealt with of many companies and the one greatest reason why they are not maximizing operations, it is sad that it is so common place in the industry. Hence, it is why I always start off my presentations to audiences with” Forget antiquated ways, go beyond your comfort zone”.

Here is just one instance of going out of ones comfort zone: 1” ball cutter, steel cutter body with abrasive particle diamond attached, machining what is called a T-shirt – composite material, running 4,000 rpm, HSK 63A interface, 18,000 rpm max spindle, 6” OAL gage length, lots of noise and vibration during the cut, operator scared to run it due to unstableness. Myself, sitting in the tool crib about 30 yards away, I hear the noise and decide to try something. I use my laptop and audio chatter recognition software, stick the microphone out the door and take a reading. This took about 60 seconds to do, a dominant chatter frequency shows up, the software suggests an RPM, I walk up to the operator, give him the RPM to try – 8,000 RPM. He freaks, says no way, was really scared now but agreed. I take the Stackup tool and check static balance, it is in a standard TG collet holder, checks okay, put the Stackup tool back in the machine and the operator runs it at 8,000 rpm. Result, cut stabilizes, operator resumes cut and finishes part in a timely manner now, I document parameters on my dynamic database for that tool so programming will know what rpm to use of this Stackup again. All this occurred in about 3 minutes and saved one heck of a lot of time on the machining operation, let alone the wear and tear on the machine tool, cutter and part. I have done this many times over for one piece jobs, this was a mold shop by the way.

I suggest you have a reputable person come in and show you how to use an Impact Test or Audio Chatter Recognition or you take a class on it - so you can experience the process. Forget antiquated ways, go beyond your comfort zone.

See video's of the process at: http://members.cox.net/camminc/

[camminc]

See:

http://members.cox.net/camminc/Metal... Chart H13.pdf

http://members.cox.net/camminc/Metal...t Aluminum.pdf

http://members.cox.net/camminc/Metal... Cast Iron.pdf

http://members.cox.net/camminc/Metal...hart steel.pdf

http://members.cox.net/camminc/Metal...t Titanium.pdf

[Scott_bob]

camminc,

Thanks for the info... I'll put this data in my things to do pile.
I'll get to it right after I replace the control on my CNC machines...
It would be like putting the cart in front of the horse otherwise.

Sincerely,

[camminc]

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.