Hello, im new here :) looking for knowledge machining with high speed spindles

Hi, Im dan

I'm a CAD Engineer by day, and a self taught machinist by night. Two years ago I bought a second hand StoneyCNC MegaMill, which has been great. I've got to grips with the basics of programming with Fusion 360. Im now fairly confident cutting aluminium, but I want to take it to the next level - thats why im here.

I tend to program very conservatively, using known recipes borrowed from internet research, small cutters (6mm) and the parts ive made so far have been small flanges and brackets. I got big ideas tho, the cutting area on the machine is huge for its class, but I need to cut faster and the complexity and time it takes to generate toolpaths in fusion is getting out of hand.

The machine has a Teknomotor 2kw spindle, it operates best between 12000-24000 and has er25 collet so goes up to 16mm tooling
The bed moves at up to 4000mm/min - I need to do some tests, but in most situations i don't see it get that high, as i don't think it accelerates fast enough. Most of the things i machine are more organic shapes, rather than straight sided.
Its all controlled through UCCNC, and ive just got a fogbuster too, to help when I ramp everything up.

Something that would help massively is if I could use that 16mm capacity and a decent tool and recipe to hog out material, I've no idea what will work tho, and tooling gets expensive at that size.

Dan

Quote:

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Originally Posted by donfrondo

small cutters (6mm)

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Small ? <0.5mm is where small starts.

Welcome to the forum Dan.

Cheers,

Rob-T

The spindle collet might take 16mm cutters, but at those spindle speeds that's going to be for cutting wood/plastic!

My own steel-built router has the usual 6K-24K spindle. I've been cutting steel with it recently, using carbide cutters 2-4mm dia, 3-flute. Typically, I'm running a 4mm cutter in steel at 6K RPM, 125mm/min, 1mm depth of cut. That's based on manufacturer's data sheet, plus experimentation. The cutters are capable of doing more but the spindle runs out of torque at these low speeds and can't handle the loads that the cutters could. I'm not necessarily recommending these settings, but they work for me so that might give you an idea of what you might be able to do. No way could I use a 16mm cutter in metal, although the spindle is capable of using something like that cutting wood. A lot of my cutting is also small fiddly bits, where a machine tuned more for acceleration than max cutting speed is useful. This link gives an idea of the art of the possible.

I also use Fusion 360 for design and CAM. Great tool, but especially with the CAM module, it takes a while to get used to the parameters that you need to set. However, now that I have been using it for a little while, actual toolpath generation is pretty quick.

Try 8mm endmill instead of 6mm. Stiffer than 6mm so can be driven harder and enough speed & torque from the 2kW motor in the range that cutter is happy with.

My thoughts are larger than that needs much more torque so starts to need indirect drive geared down through pulleys or if direct drive spindle the industrial motors of 10-15 kW upwards.

My advice is get HSMAdviser and use it constantly to perfect your toolpaths. I know of nothing better for the purpose.

Working on a machine without ATC is always a compromise. so you will have to live with your choices. I use mainly 3 sizes- 12mm or 1/2 inch, 6mm and 3mm or 1/8. Where 12mm is insert tool. So a combination of this is best for most jobs. Add the time and hassle for changing tool and then you decide.


So insert tooling will help greatly with speed. I use 1/2 CMT for most cleaning jobs, its one flute. On 16mm you can use even better cutters.