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Where did the HEM / high speed machining SF come from?

evega

Plastic
Joined
Jul 22, 2018
Hey everyone,
I'm working on upgrading my programing skills and introducing my shop to HEM / high speed machining. The thing that stumps me is: how did Helical Solutions get 1,000 SF in 1018 steel in a youtube video when that tools data on the website is listed as about 240 SF ?? After looking and reading around for a few months, I'm starting to think it's either that I'm not understanding what's out there or that there is no real number/formula to go by and it's more of a concept per application/part while less 'old school-this range is what it has to to be'.

My goal is to show this style of programming can benefit our shop by reprogramming a few parts and showing a comparison of the results. The materials I'd like to try this on are 17-7, 304 and 316. We're set up with good sturdy machines with 10k,12k,20k spindles and a wide range of good end mill brands so I'm confident we're equipped.

Understandably, there will be some amount trial and error but I'd like to reduce the scrap, broken tools and set-up time as much as possible before attempting this with a steel part on company time.
 
One thing I usually do is reach out to whatever tool representative who's tool I'm using to ask them. Some tool manufacturers haven't really updated their information on their websites/catalogs for HSM. Others are just too generic and wide of a range to really be useful, I'm looking at you Iscar.
 
SFM will be more related to tool coating and material type. Feed rates are based on chip thinning. 240 sounds really low for anything using even a generic uncoated carbide endmill? Are you sure you have your tool set as carbide material?
 
I use Volumill numbers posted from Gibbs for high speed toolpaths.
In one version of Gibbs I think those numbers were actually "powered by" Helical?????
I think Helical has some high speed machining calculators that you can download.

Doesnt exactly answer your question.....
I believe the feeds are generated using "chip thinning" principles. Not sure about the Surface footage...
 
Less step over allows more SFM. I run over 1000 SFM all the time in steel, but never with coolant, only dry or compressed air.

Almost all my steel programs will run the finisher slower (SFM) than the rougher :D
 
I run over 1000 SFM all the time in steel, but never with coolant, only dry or compressed air.

^^^I have found this to be the most critical part when going for sky high SFM's.^^^

Another note; while there is a sweet spot for SMF's - as a general rule faster RPM just means it's going to wear out quicker. Sometimes the vendors will release demo videos showing tools doing really insane MRR's, but they are cutting at speeds that will burn up tools in minutes.
 
Less step over allows more SFM. I run over 1000 SFM all the time in steel, but never with coolant, only dry or compressed air.

Almost all my steel programs will run the finisher slower (SFM) than the rougher :D

mind explaining the no coolant? cold shock?
 
I've double checked and it's 200 SFM on the tools data chart. My guess is that's the old school programming or general purpose SF.
It sounds like there should be a chip thinning formula or calculator I should track down.
I didn't realize the chip thinning had it's own formula. I understood it to be a term as a result of high rpm/feed rate w/ small step over of the tool's diameter.
I'm sure I've seen some downloadable stuff on Helical's site, looks like that's my next step to explore. If that fails I'll call one of my tool reps ask what they have to help.
 
mind explaining the no coolant? cold shock?

Based on what I've read ...

Yes. The carbide gets really hot really quickly, but since it's in and out of the cut relatively quickly (compared to high-engagement "plowing-style" cuts), it spends a lot of time in air cooling down a bit before getting back in the cut. If you apply flood coolant, it will still get real hot in the cut, but then will be shocked once it exits and gets bathed in coolant.

Regards.

Mike
 
Based on what I've read ...

Yes. The carbide gets really hot really quickly, but since it's in and out of the cut relatively quickly (compared to high-engagement "plowing-style" cuts), it spends a lot of time in air cooling down a bit before getting back in the cut. If you apply flood coolant, it will still get real hot in the cut, but then will be shocked once it exits and gets bathed in coolant.

Regards.

Mike

We have had to run carbide at time in full coolant because we lacked the proper air line. On some of my other machines we added an air line and you are correct about shocking the tool. I watched a perfect tool pop once we gave it a splash of coolant. Either run it full in collant or no coolant at all.
 
Based on what I've read ...

Yes. The carbide gets really hot really quickly, but since it's in and out of the cut relatively quickly (compared to high-engagement "plowing-style" cuts), it spends a lot of time in air cooling down a bit before getting back in the cut. If you apply flood coolant, it will still get real hot in the cut, but then will be shocked once it exits and gets bathed in coolant.

Regards.

Mike

Agree with what you said....
I have also been told ....dont know it as fact.....that some of the coatings used in tools designed for high speed toolpaths are more effective with SOME heat.
 
Pretty much what everyone has said but I will add,

Even if you can keep the tool completely submerged there is still microscopic thermal shocking occurring that will shorten tool life.

Carbide is not like steel in that carbide does not mind the heat. I run compressed air for chip evacuation and to cool the tool holder, I really don't care how hot the tool itself is.

It is my understanding that coatings with Al need heat to help turn the Al into oxide, though I could be wrong as I am just a guy who uses the tools :o

Somewhere I have some videos on my phone of dull tools glowing orange but still cutting for 30-60 minutes before they finally give up. Needless to say a nice smooth toolpath is needed.
 
I've double checked and it's 200 SFM on the tools data chart. My guess is that's the old school programming or general purpose SF.
It sounds like there should be a chip thinning formula or calculator I should track down.
I didn't realize the chip thinning had it's own formula. I understood it to be a term as a result of high rpm/feed rate w/ small step over of the tool's diameter.
I'm sure I've seen some downloadable stuff on Helical's site, looks like that's my next step to explore. If that fails I'll call one of my tool reps ask what they have to help.

Yeah, that's for "regular" milling. Right on their homepage they have a link to download machining adviser pro. That's where you'll get the outrageous numbers from. It's a pretty decent app as far as customization goes but the numbers still come out a little ambitious for my liking.
 
Agree with what you said....
I have also been told ....dont know it as fact.....that some of the coatings used in tools designed for high speed toolpaths are more effective with SOME heat.

I had a Seco guy at one time tell me this is called "hot hardness", and there's a sweet spot to be at for optimal cutting...hence no coolant in certain materials. He seemed like a sharp dude and his tools always worked the best so I'm inclined to believe him.
 
Ive run steel EMs with AlTain or TiAln coatings both dry and flooded. In my old job we only ran them dry and only about 250SFM. They cut great for plowing toolpaths.

Ive experimented with dry vs flood in my current shop and with 4140 i like to run dry. with Stainless Steels I always run flood coolant. THe thermal shocking is real, as well as the coolant needing to be "activated" by heat. But with stainless I get better surface finish with flood! And whenever Im running stainless its usually something that needs an optimum finish so I flood it at the expense of shorter tool life.

I do this regardless if my SFM is 250 or 1000. I can't imagine running a carbide endmill with more than 1000 SFM in any steel. Shoot i run some of my aluminum cutters at 1200.
 
Titanium coatings TiN, TiCN, TiAlN, AlTiN - HANNIBAL CARBIDE TOOL, INC.

A quick primer for anyone interested. I've been out of milling any type of steel for years now, but I know some coatings are (were) designed specifically to cut dry/air blast.

That list does not have AlCrN which is what I use the most. In the past I have looked and was never able to find one list that had all or even most coatings.

It is my understanding the Ti is needed to get the Al to bond to the carbide. Cr does a better job than Ti in almost every aspect which is why you see it on higher performance tooling.....I think. Maybe someone like CarbideBob can shed some more light on the topic??
 
That list does not have AlCrN which is what I use the most. In the past I have looked and was never able to find one list that had all or even most coatings.

It is my understanding the Ti is needed to get the Al to bond to the carbide. Cr does a better job than Ti in almost every aspect which is why you see it on higher performance tooling.....I think. Maybe someone like CarbideBob can shed some more light on the topic??

Absolutely! Now I *think* almost every carbide/tooling company offers some "exotic/proprietary" coating such as

Nacro, Firex, Nano-*, Wxl... you get lost trying to find the perfect coating :D
 
Absolutely! Now I *think* almost every carbide/tooling company offers some "exotic/proprietary" coating such as

Nacro, Firex, Nano-*, Wxl... you get lost trying to find the perfect coating :D

I just assumed that those were a bit gimmicky but perhaps my assumption is misguided? i guess if you're working on exotic alloys you do really need to dial the perfect coating in, but for most stuff it seems irrelevant (assuming you choose the right coating for the material)
 
I've read here on PM time and time again about no coolant on steel, use compressed air. I have not really adopted this yet because I don't have a good air blow system on my machine for chip removal. It's on the list.

I have asked two tooling suppliers about this and they acted like I was crazy to ask. Use coolant they said. Maybe I'm exaggerating a a little but still they absolutely recommended coolant. I've looked around some on mfr's sites and have never seen this recomendation (no coolant) except here. Any other references you guys can point me to?
 








 
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