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Musht
28-11-2012, 12:38 AM
Just wondering with all the debate about how rigid have to be to mill aluminium, does nobody mill steel or is the rigidity beyond feasible for small workshop ?

Thanks
Adam

i2i
28-11-2012, 12:39 AM
no probs at all

martin54
28-11-2012, 11:24 AM
As well as a ridged machine you need a spindle capable of machining steel Adam, from what I have read the Chinese spindles that are popular don't perform very well at slower speeds which you need for machining steel.

m_c
28-11-2012, 06:29 PM
It depends on what you're trying to acheive?

Yes you can tickle bits of steel with a flimsy machine, but you'll struggle with cutter life, tolerance and finish. It's not impossble though, as plenty people produce good parts with nothing but a X1, but it takes a lot more time and effort than a reasonably sized mill.

Musht
01-12-2012, 02:04 PM
Partly general question, steel seems to never get mentioned, hadn`t struck me about lower speed/ higher torque spindles, thanks.

Looking at panel cutting for connectors, steel preferable to alloy in some uses and wondering if its a different machine to one that might mill chunks of alloy.

Thanks
Adam

JAZZCNC
01-12-2012, 02:18 PM
There's no problem cutting steel with Chinese WC spindles if the machines strong enough to handle the forces. It just requires the correct cutters which can cut metal at high spindle speeds. They are available to cut either dry or with suds and Like M_C says don't expect to hog great big lumps at a time but you still can get good finish and reasonable feed rates if the machines upto the forces.

i2i
01-12-2012, 10:38 PM
i have no problem cutting steel as i'm using a "milling machine" not a "router".

I say this waiting for the onslaught of "a router mills just as well as a mill", and, " my machine cuts steel perfectly well if i pray to allah three time a week and the devil the last four".

Steel doesn't get mentioned here much because this is primarily a router based forum, and because of a routers construction and operating speed, cutting steel is not it's primary function.

JAZZCNC
01-12-2012, 11:23 PM
I say this waiting for the onslaught of "a router mills just as well as a mill", and, " my machine cuts steel perfectly well if i pray to allah three time a week and the devil the last four".

The devils in the details i2i and it can be done on a strong router with the right tooling and only three hail mary's .. . Lol . . . Knocks the shit out of it thou and not something I'd do on a daily basis or even monthly if can be avoided.!!

i2i
01-12-2012, 11:40 PM
only three, i'm surprised.....lol

Musht
02-12-2012, 01:58 PM
A mill having a fixed Z turret and moving X Y slides, and a router having a fixed table and moving gantry?

So if wanted to mill, say chocolate moulds, , as an example thats come up before,fairly deep/ high level of finish, in steel, would really need to be on heavy iron fixed turret mill to get there?

If wanted to cut square holes in 2.5mm mild steel , a moving gantry router would be feasible but probably not optimal?

Yes, strikes me that cutting holes in plate is more a plasma cutter or for quite a few dollars more laser optimal operation, just looking at ideas at moment.

Appreciate people taking the time to answer what are very basic questions.

Cheers
Adam

i2i
02-12-2012, 02:12 PM
if you go with a small diameter carbide or coated hss slot drill/end mill, you're going to cope better with the higher speeds that the router gives. Then create a localised coolant dam to keep things cool, you'll probably get by.

JAZZCNC
02-12-2012, 03:22 PM
A mill having a fixed Z turret and moving X Y slides, and a router having a fixed table and moving gantry?

So if wanted to mill, say chocolate moulds, , as an example thats come up before,fairly deep/ high level of finish, in steel, would really need to be on heavy iron fixed turret mill to get there?

If the routers frame and Z axis is strong and you keep the extension to a minimum by lifting the work to the spindle then it will do it no problem with the correct end mills. Yes Slower when it comes to removing large amounts of material but not when it comes to finish on small things like moulds.
The moving bed or gantry doesn't really come into it. Just more common for mills and easier to build strong machines with limited travel if fixed gantry.

The higher speed of router spindles will actually give you a better finish than slow milling spindles when using small end mills needed for detailed moulds like you suggest has they often don't spin much above 3000rpm and 10,000 rpm + is not uncommon.

That said if I was mainly or even just more than occasionally cutting steel then I'd buy a Mill with the fastest spindle I could afford or buy speed increaser.!! Steel really does stress a router out.!

m_c
02-12-2012, 07:00 PM
A mill having a fixed Z turret and moving X Y slides, and a router having a fixed table and moving gantry?


Quite a few CNC mills have fixed tables, it's just that conventional mills were all pretty much moving table.
The difference between a mill / router is more of construction than anything else, with mills generally having lots more weight with a lower speed spindle capable of high torque, whereas routers are generally lighter with a higher speed spindle/less torque. There are off course lots of exceptions to those, with some routers being more than capable of handling steel, and mills with high speed spindles, but the big difference is the mill hold tight tolerances all day long, whereas routers are generally not as accurate.