Asian High speed ER collet spindles

Hi All

I am thinking of purchasing a High speed spindle and VFD. There is a vast number if videos on the net showing them cutting at 20 or so thousand RPM. Fine for wood and slowed down a bit for Aluminium. But what If one is slowed down to a speed that will cut steel at the correct speeds for high speed steel? (Max 12mm Diameter end mills)

Say 1000 to 3000 RPM. Yes I know the torque will be down, quite a lot in fact.

So my question is has any member actually tried it. Was it successful or did it the spindle not have enough power and stall. Some are water cooled and I guess this would be an advantage at slower speeds.

They are sold with various power ratings I would be prepared to buy a higher rated one if it can do the job. Some are rated at over 3KW, that's a little less than a medium size knee mill spindle motor. I have seen a few graphs that suggest it may be possible but I am inclined to misbelieve them. This is where first hand knowledge is a lot better.

Regards
John

No 7,000 is about the lowest they will go.

There's a reason standard machines don't go to those speeds. However if you want to try it then why not look at a speed increaser as a compromise?

Hi John

I bought a 1.5kw water cooled spindle off ebay which I use on my CNC milling machine. Brilliant for the price and has run for many hours without a hiccup.

I use it down to 3000 rpm without problems - but as JS says, it's probably not meant to run at that, but it stays cool with a proper chiller and runs well.

But there's not a cat in hells chance of using a 12mm cutter in it - 6mm in aluminium is on its limit. Steel with a 4mm is about right.

Cheers - Will

I cut hss up with a Lidl dremel type tool and my lathe. Those little disc cutters are very good.

The bottom line is: What do you want to cut?

With enough patience you can do pretty much anything you want

.

Have you read the first post ?

HSS and grinders were not mentioned

But what If one is slowed down to a speed that will cut steel at the correct speeds for high speed steel? (Max 12mm Diameter end mills)

The thing is John, why would you you spend so much time worrying about me?

Spend more time worrying about the original poster please

Have a nice day John, and focus on the original poster please

Edited By Ady1 on 07/05/2015 01:24:37

.

He means High Speed Steel cutters, not high speed steel material

Hang on a minit... does he want to stuff a 12mm cutter into a 20,000 rpm unit?

Yeah. ok. I defer

So are ear defenders and coolant going to be mentioned? And is this unit going to be hand held with thick felt gloves?

They had a CNC router with one of these spindles where I used to work. Fine on wood and plastics but they found it useless on aluminium. They snapped carbide cutters every week on it.

Hi All Thanks for responding.

Will Bells has cut steel with his, that's good. "6mm in aluminium is on its limit. Steel with a 4mm is about right." but no chance with 12mm. Using a 1.5kw spindle. Maybe a 3kw machine will be able to drive larger cutters say six and eight mm or even eight and ten mm cutters?

Vic's comment re cutter breakage is interesting. Maybe the machine was not rigid enough or the feed and speed settings were wrong? It should not happen.

A mate and I are building 2 routers from scratch, made from laser cut 5 and 8mm steel sheet, travels are 850 by 1850mm Z travel is 190mm, no aluminium just steel sheet and lots of it. very heavy and rigid I started the CAD design before Christmas and it has been evolving quite well. Oh and no welding!

Yes there are a heap of existing designs out there but we like this one!

It is a pity the Asian spindles don't have a wider torque range. The high speed spindle will be perfect for timber particle board and plywood, also plastics and aluminium. Browsing the net has proved that it will work. There are many examples of great work. We have already made one router A lighter design and posted it here on the MEW forum.

At the moment I have not found a solution to the spindle design I am happy with. Maybe in the end the machine will have to have two spindles; one low speed, and one high. A clumsy way to do it really. Wide speed range spindles are available if you can afford the cost of a small car to pay for one, that is out of the question.

There are examples on you tube of routers cutting steel this link is a good example: **LINK** or this but it is thin SS sheet **LINK**

The feeds and speeds in both examples are impressive.

Regards
John

The macjhine

They make one for cutting steel, but are considerably more money than the one sold for wood cutting routers.

Neil

Agreed about cutters not supposed to break. The router replaced a small CNC mill and they really had trouble getting used to the new machine. They used long series cutters in carbide, perhaps HSS would have been better and the feeds were probably too high. Big slabs of special alloy supposed to be more suitable were bought in but made no difference. I had a few small off cuts and it cut nicely on my mill.

Oh, and yes, the machine itself was pretty flimsy in my opinion.

Sorry about my confused state there

On my drummond you can use both 6 and 12mm cutters but the 12mm has such a large surface area the 6mm hss works much faster on steel, it cuts more cleanly and more controllably

The smaller 6mm would be used to cut a 12mm slot in half inch steel nowadays, and it would do it in half the time with less noise and a single pass for each cut

Edited By Ady1 on 07/05/2015 11:14:55

These machines are going to be limited by their torque, not their power, due to the laws of physics. If you choose to operate one at 10% of its rated speed, you are only going to be able to get about 10% of the power out of it. Conversely with this approach, if you want something like 2kW at 2000rpm, you are going to need a motor (and matching inverter) rated at about 20kW. That's possible but it will cost you. I'm not sure that's the solution you are looking for.

If you are going to drive the cutter directly, you should aim for a motor that is designed for that speed. Of course, if you subsequently decide to use a smaller cutter, it will require less torque, so you could then run the motor above its design speed. You won't get the same torque and power out of it but surely with a smaller cutter you won't need it....

Murray

A proper speed controller, one that takes the measured speed of the spindle as feedback and adjusts the power of the motor accordingly would allow a high speed motor to be used a lower speeds without running out of torque. This approach is much more cost effective: a magnet and reed switch or even hall effect sensor (and microcontroller) are much cheaper than a 20kW motor.

EDIT:

Just realised you're probably talking AC motors with a VFD. In that case you may want to separate out the cooling of the motor, from the speed of the motor. Maybe have the speed controller controlling a fan and feed into the speed controller some degree of information about the characteristics of the motor and a way of estimating power dissipation, or directly measure that too/instead

Edited By Thomas Dye on 12/04/2018 20:03:19.

Edited By Thomas Dye on 12/04/2018 20:11:03

Edited By Thomas Dye on 12/04/2018 20:11:38

In my last job we cut any material from ally to hardened HSS to 55 Rc with carbide cutters some coated and some diamond coated but ocasionaly someone would program cutter path wrong and smash cutter. I have seen parts of cutters protruding through 8 mm polycarbonate sheet guarding. !

David