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Peripheral cooling through tool holder at high rpm

was considering to try Big Kaiser hydraulic holder
These are excellent holders. I used them hard machining warm forge dies to a .003mm CMM tolerance, material was up to 62 HRC. We also use them machining formula one and Indy car racks from hardened martempering steel.

We had the Jabro rep come round and try sell us cutters. He asked if the job was polished, no straight off the machine. Asked if we used heat shrink holders, no not accurate enough. We clocked every flute on the OSG cutters to .002mm TIR.
 
Contact your Rego Fix salesman and see if there are any shops local to you that have the assembly press. Maybe someone would be willing to let you use theirs.

I think runout and harmonics are your main issues. Harmonics in the tool AND from the part. Flood coolant would be my choice for your part.
 
I like the idea of the 90 degree head and a saw!

However, in terms of holders with decent CTS bypass, I like:
- Big Kaiser Hydraulic Jet Through - these don't need collets and have peripheral jets pointing inwards
Video (versus just spraying through a collet):
https://www.instagram.com/p/CtBe7zOoeDv/

- Big Kaiser standard hydraulic with the PSC bypass collets. These look more like the Regofix style. There isn't obviously a gap between the tool and the collet, so it comes out very much planar with the tool shank
Video:
https://www.instagram.com/p/C0mmtmpIgOA/

Note, I've only got the older CTS pumps, so something like 250-300psi? The newer machines with 1,000Psi will do a much better job of getting the coolant onto the part.

There are also a few people do a nice angled shrink with coolant jets. Try Bilz. But they are similar money to the hydraulic from Big K... I only own the cheaper Bilz ones you see on the video above and they are rather meh for coolant jets, about as good as firing through a collet. However, it wets the surface, and they are cheaper than a collet holder (here), so I like them. I would swap to the angled ones if they weren't so expensive though!

I've not tried the Regofix stuff, but they seem like the best in the business in every other way... With these small tools runout is a big issue, so I think some kind of premium holder will be a help?

With regards to endmills you could try the Sandvik Plura (?) things. They have variable everything geometry. I looked at them for a slotting job (went with another solution in the end)
 
I like the idea of the 90 degree head and a saw!

However, in terms of holders with decent CTS bypass, I like:
- Big Kaiser Hydraulic Jet Through - these don't need collets and have peripheral jets pointing inwards
Video (versus just spraying through a collet):
https://www.instagram.com/p/CtBe7zOoeDv/

- Big Kaiser standard hydraulic with the PSC bypass collets. These look more like the Regofix style. There isn't obviously a gap between the tool and the collet, so it comes out very much planar with the tool shank
Video:
https://www.instagram.com/p/C0mmtmpIgOA/

Note, I've only got the older CTS pumps, so something like 250-300psi? The newer machines with 1,000Psi will do a much better job of getting the coolant onto the part.

There are also a few people do a nice angled shrink with coolant jets. Try Bilz. But they are similar money to the hydraulic from Big K... I only own the cheaper Bilz ones you see on the video above and they are rather meh for coolant jets, about as good as firing through a collet. However, it wets the surface, and they are cheaper than a collet holder (here), so I like them. I would swap to the angled ones if they weren't so expensive though!

I've not tried the Regofix stuff, but they seem like the best in the business in every other way... With these small tools runout is a big issue, so I think some kind of premium holder will be a help?

With regards to endmills you could try the Sandvik Plura (?) things. They have variable everything geometry. I looked at them for a slotting job (went with another solution in the end)
Seeing this video was very helpful however I'm more prone to think that with a tool that tapers form 6mm shank to 2mm cutting diameter no coolant will reach the cutting zone at 15k rpm no matter what. All this solution seems to be aiming to a cutting zone for a tool with cutting diameter equal to the shank diameter.
I'm very pronte to invest in Regofix now, the hand pump system is capable enough and shouldn't be too expensive and the single toolholder is less expensive then hydraulic. They also basically claim to be the best in all applications and users in this forum seems to confirm that.
 
Seeing this video was very helpful however I'm more prone to think that with a tool that tapers form 6mm shank to 2mm cutting diameter no coolant will reach the cutting zone at 15k rpm no matter what. All this solution seems to be aiming to a cutting zone for a tool with cutting diameter equal to the shank diameter.
I'm very pronte to invest in Regofix now, the hand pump system is capable enough and shouldn't be too expensive and the single toolholder is less expensive then hydraulic. They also basically claim to be the best in all applications and users in this forum seems to confirm that.
None of the coolant flush/jet style holders and/or collets are going to help get coolant to a tool with an oversized shank. The only ones that will are the style that the coolant goes through three holes in the shank and act like the CF collet but built into the shank of the tool. That way the coolant comes out right against the 2mm portion of the endmill. I wouldn't get one where the tsc hole goes all the way through the tool, since it'll just weaken an already not strong endmill. Main benefit from the holders mentioned is they have lower runout which will improve your tool life substantially with an endmill that small. Another option is to get an endmill slightly smaller than 2mm like 0.071" and "helically ramp" the profile of the slot at ~0.75D per pass. You'd get a better finish and you can control size better, and would likely be faster.
 
It was in alu, but I used the Big K hydraulic with the outside peripheral jets, quite successfully with a 6mm shank tool cutting a 2mm width slot. I will put up a video on my instagram feed in the next few weeks, but it's a customer part and needs their go ahead to post it. I concede it was only 1D deep, but it was an O-ring groove into a recessed area which was partly blocked to the flood coolant. I ran it around 25-50% harder than manufacturers suggested feeds and got a very nice finish. If i had lots more to do I wouldn't have hesitated pushing the tool harder to see where it broke.

My thought would be to try a fancy tool holder which has aimed coolant jets and just give it a try to see what cut is fastest (deep and slower or faster in multiple passes, etc). Break a few end cheaper end mills and then you have a benchmark to compare fancy things against?
 
Seeing this video was very helpful however I'm more prone to think that with a tool that tapers form 6mm shank to 2mm cutting diameter no coolant will reach the cutting zone at 15k rpm no matter what.

Dear Stefano,

Well, you answered your question; no tool holder will do a perfect job if you are running a tool that is necked down from 6mm to 2mm.

Also, as suggested by others, the coolant pressure is low. I would rather spend my money upgrading the pump before investing in a Powrgrip, Shrink fit, or any other high-end system.
More coolant pressure is always beneficial, but I do not know how difficult/costly it would be to upgrade your machine.

Since they say a picture is worth a thousand words, I took some.

(Mods and other members, please be kind to me and excuse the wall of pictures and text, first post on PM, but I felt I could finally chime in with something useful regarding OP's post)

It might help you save some money before buying a whole new tool-holding system if it later turns out it does not help you with this application.
Also, remember that in theory, the higher pressure you have available helps to combat the centrifugal force creating the "umbrella effect" around the tool, so basically, the more pressure you have available, the faster you can spin the tool while still getting good coolant delivery to the cutting edge.

However, you mentioned that you were running it in a Tendo EC, right?
So, you were probably using a standard GZB-S PK sleeve.
These things are not really suitable for anywhere near 15k rpm.
They really start to fall off after 5k-6k rpm. I run these with Ø10-12-16mm endmills, mostly in SS. It's not really suitable for anything faster.

All the pictures of the cooling performance are with a 2mm endmill with a 6mm shank, running at 3k and 12k. (I know the Z is high and unrealistic when milling, but this was done on purpose just so you can see and compare the overall spread)
The same collet as you have used at 3k:
EC-3K.jpg

And 12k:
EC-12K.jpg
As you already know, this is not really usable...

I do not have a Powrgrip CF collect or the Regofix system at hand in our shop, but maybe someone else can chime in... However, this Tendo CF holder has cooling slots on the same principle as the Regofix CF collet.

The cooling slots are still straight and not oriented on the Regofix CF and this Schunk CF:
CF.jpg

As you can see, it is much better at providing a constant "beam" of coolant, just like the others have mentioned.
At 3k:
CF-3K.jpg

However, at 12K, it is still not really going to the cutting edge since the mill has an oversized shank:

CF-12K.jpg

Still, it might be cheaper since you can only buy one, and no need to buy the Regofix press.

Regarding the holders that have angled coolant bores, well, again, these are made with a nominal tool size in mind. On the newer Haimer ones, from 6mm and below, like those in the picture, you can also screw in some jets, similar to the ones that are on Sandvik HP tooling.

Again, only a little help with your current pump setup. Second, since it is a holder for a 6mm shank, you have to have around 27-28mm stick out with a 6mm endmill to get optimal coolant delivery to the edge:

H-3K Closeup.jpg

It's not much help for a 2mm endmill doing slots. And here is the general performance of the Cooljet holders:
3k:
H-3K.jpg
12k:
H-12K.jpg

Haimer also does the Cool Flash, which is more geared toward higher RPM. They laser weld a disc with nozzles at the tip of the holder, and then it behaves like the Regofix CF or the Schunk CF I have posted above, but again, you will need more pump pressure.
Another thing is that these are made to order, so there is more lead time, and they cost more.

You mentioned that you tried to get the quote for internal coolant endmills; honestly, this is the direction I would take.

The Micro Diver from Guhring you mentioned is currently my top choice for small endmills in challenging materials. I use these exclusively for slotting in 316Ti and Ti-6Al-4V. It is a relatively new product even for Guhring, but overall, I think I have broken maybe one out of 50, but I suspect the material. It is an excellent tool to have at hand. I use it both on mills and in-driven tools in mill turns with good tool life and process stability.

These things have proper coolant flow for your application, even at high RPM.

At 3k:
MD-3K.jpg

And at 12k:
MD-12K.jpg

They are somewhat reasonably priced, but then again I know this is a highly subjective matter.
I do not know if you have received the quote yet, but let's say I can buy almost two for the price of one of the Crazymill, as mentioned earlier. Then again, I use Mikron like twice a year.

The MSRP is around 70€ for the 2mm Micro Diver you need, but you should be able to get 30-40% off easily... It is a new product, and they are looking for people to run it.

I still have to convince the kind people at Guhring to cut off the used half and regrind / recoat, since I do only shallow slots for one application, and the upper half is untouched. But I have not tried yet; I would feel like a massive cheapskate if I asked for a 2.5-3mm end mill regrind :D

Since you are in Europe, like me, why not take advantage of it?
I do not know how well Guhring is represented in Italy, but since it is a repeat job, why not have them come over to do a test cut? And if it is good, then buy it... This is exactly the way I found out about these last year. I had an issue, did some test cuts, and have bought them ever since.

The same goes for the more expensive tool holders; before you invest a lot of your own money to find out it is not working out as you might have thought, test them out.

If I can get people from Shunk or Haimer to come and do a test cut, you should also be able to do so. I know for a fact that even if you do not have a shrink-fit machine at hand, Haimer will shrink your own tool if you send it to them and pay for the shipping; the Germans really have great support if you are in the EU, so why not take full advantage of it ;)
 
Dear Stefano,

Well, you answered your question; no tool holder will do a perfect job if you are running a tool that is necked down from 6mm to 2mm.

Also, as suggested by others, the coolant pressure is low. I would rather spend my money upgrading the pump before investing in a Powrgrip, Shrink fit, or any other high-end system.
More coolant pressure is always beneficial, but I do not know how difficult/costly it would be to upgrade your machine.

Since they say a picture is worth a thousand words, I took some.

(Mods and other members, please be kind to me and excuse the wall of pictures and text, first post on PM, but I felt I could finally chime in with something useful regarding OP's post)

It might help you save some money before buying a whole new tool-holding system if it later turns out it does not help you with this application.
Also, remember that in theory, the higher pressure you have available helps to combat the centrifugal force creating the "umbrella effect" around the tool, so basically, the more pressure you have available, the faster you can spin the tool while still getting good coolant delivery to the cutting edge.

However, you mentioned that you were running it in a Tendo EC, right?
So, you were probably using a standard GZB-S PK sleeve.
These things are not really suitable for anywhere near 15k rpm.
They really start to fall off after 5k-6k rpm. I run these with Ø10-12-16mm endmills, mostly in SS. It's not really suitable for anything faster.

All the pictures of the cooling performance are with a 2mm endmill with a 6mm shank, running at 3k and 12k. (I know the Z is high and unrealistic when milling, but this was done on purpose just so you can see and compare the overall spread)
The same collet as you have used at 3k:
View attachment 422313

And 12k:
View attachment 422314
As you already know, this is not really usable...

I do not have a Powrgrip CF collect or the Regofix system at hand in our shop, but maybe someone else can chime in... However, this Tendo CF holder has cooling slots on the same principle as the Regofix CF collet.

The cooling slots are still straight and not oriented on the Regofix CF and this Schunk CF:
View attachment 422316

As you can see, it is much better at providing a constant "beam" of coolant, just like the others have mentioned.
At 3k:
View attachment 422317

However, at 12K, it is still not really going to the cutting edge since the mill has an oversized shank:

View attachment 422318

Still, it might be cheaper since you can only buy one, and no need to buy the Regofix press.

Regarding the holders that have angled coolant bores, well, again, these are made with a nominal tool size in mind. On the newer Haimer ones, from 6mm and below, like those in the picture, you can also screw in some jets, similar to the ones that are on Sandvik HP tooling.

Again, only a little help with your current pump setup. Second, since it is a holder for a 6mm shank, you have to have around 27-28mm stick out with a 6mm endmill to get optimal coolant delivery to the edge:

View attachment 422319

It's not much help for a 2mm endmill doing slots. And here is the general performance of the Cooljet holders:
3k:
View attachment 422320
12k:
View attachment 422321

Haimer also does the Cool Flash, which is more geared toward higher RPM. They laser weld a disc with nozzles at the tip of the holder, and then it behaves like the Regofix CF or the Schunk CF I have posted above, but again, you will need more pump pressure.
Another thing is that these are made to order, so there is more lead time, and they cost more.

You mentioned that you tried to get the quote for internal coolant endmills; honestly, this is the direction I would take.

The Micro Diver from Guhring you mentioned is currently my top choice for small endmills in challenging materials. I use these exclusively for slotting in 316Ti and Ti-6Al-4V. It is a relatively new product even for Guhring, but overall, I think I have broken maybe one out of 50, but I suspect the material. It is an excellent tool to have at hand. I use it both on mills and in-driven tools in mill turns with good tool life and process stability.

These things have proper coolant flow for your application, even at high RPM.

At 3k:
View attachment 422323

And at 12k:
View attachment 422324

They are somewhat reasonably priced, but then again I know this is a highly subjective matter.
I do not know if you have received the quote yet, but let's say I can buy almost two for the price of one of the Crazymill, as mentioned earlier. Then again, I use Mikron like twice a year.

The MSRP is around 70€ for the 2mm Micro Diver you need, but you should be able to get 30-40% off easily... It is a new product, and they are looking for people to run it.

I still have to convince the kind people at Guhring to cut off the used half and regrind / recoat, since I do only shallow slots for one application, and the upper half is untouched. But I have not tried yet; I would feel like a massive cheapskate if I asked for a 2.5-3mm end mill regrind :D

Since you are in Europe, like me, why not take advantage of it?
I do not know how well Guhring is represented in Italy, but since it is a repeat job, why not have them come over to do a test cut? And if it is good, then buy it... This is exactly the way I found out about these last year. I had an issue, did some test cuts, and have bought them ever since.

The same goes for the more expensive tool holders; before you invest a lot of your own money to find out it is not working out as you might have thought, test them out.

If I can get people from Shunk or Haimer to come and do a test cut, you should also be able to do so. I know for a fact that even if you do not have a shrink-fit machine at hand, Haimer will shrink your own tool if you send it to them and pay for the shipping; the Germans really have great support if you are in the EU, so why not take full advantage of it ;)
Thanks for the superb answer; I really am grateful for the time you took to make photos.

Unfortunately I'm in Italy but I live and work in Sicily (southern Italy), which is not as industrialized as the north, and tool companies have not a huge presence here and it is hard to have someone at you door unless you are a big machine shop or you have a production job. Italy is a long country and Sicily is an island so coming here means to take the a airplane and rent a car.

I'm waiting for the Ghuring distributor to send me the quote, I wrote to them during holydays so I have yet to understand if they ignored my request (as it often happen) o they are still closed. The 70€ MSRP is already lower than Mikron final offer.

As for tool holding after reading all the users suggestions I will test again the flood coolant with some variation and keep using the two Schunk hydraulics holders I own; ER collets holder are basically not an option for this application. I also bought a bunch of chinese tools. The job is something that I would like to become a repeat one but this will depend on how low I can keep the price. Since the shop is new and the alternative to work at a lower price per hour is not to work at all I can say that the price is fixed (at a low point) and going faster is not that important; minimizing consumable cost is crucial.

A side note about services. While is true that I'm in Europe, many companies that might sell directly in Germany here are represented by some reseller or distributor, even a japanese company such as Okuma has a direct presence in Germany and a reseller in Italy. As a novice with no mentors to consult I have not very well understood to which extent dealing with resellers is worst then dealing with the company itself.
 
I do not have a Powrgrip CF collect or the Regofix system at hand in our shop, but maybe someone else can chime in... However, this Tendo CF holder has cooling slots on the same principle as the Regofix CF collet.

The cooling slots are still straight and not oriented on the Regofix CF and this Schunk CF:
View attachment 422316

RegoFix offers two styles of collet with through coolant provisions for solid tools:

CoolFlush - where the coolant passages are half-moon slots integral with the tool shank.

Cool Bore - where the coolant passages are individual bores running parallel (but not shared with) the tool shank bore.

Having tested both, Cool Flush works exactly as you described the Schunk holders running. OK at lower RPM, but fans out at practical/useable RPM.

CoolBore has totally different performance and makes a straight column of coolant around the tool. Even with a 6mm shank and a 2mm cutter, one would think the volume of coolant getting applied just a couple of mm away is going to splash with vigor on the cutting edges and effectively evacuate chips.

Like everything RegoFix, the downside is price. Standard Rego PG collets run about $140. CoolFlush units are ~$180. The superior Cool Bore collets? $240.
 
Rego Fix Powrgrip "CF" collets are the very best I've found for high RPM external coolant coverage. I run them up to 16,000 RPM and am very happy with the way the coolant doesn't fan out. However, I have 450psi (3.1mpa). Your through coolant pressure is very low.
regofix user here as well and a big fan of their CF collets. however they do flare out quite a bit at high rpm's.
 
regofix user here as well and a big fan of their CF collets. however they do flare out quite a bit at high rpm's.
That is because we’ve all been fucking up. The Cool Flush collet is the meh one, with the coolant passages in the shank bore.

The Cool Bore collets are the ones with individual passages outside the shank bore- these are the bee’s knees.
 
That is because we’ve all been fucking up. The Cool Flush collet is the meh one, with the coolant passages in the shank bore.

The Cool Bore collets are the ones with individual passages outside the shank bore- these are the bee’s knees.
i'll definitely have to try those, thanks for the tip!
 








 
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