The New Machine

[Jonathan]

The ones at Zapp are close, but still more than Kelling. I'm surprised as I've spent ages looking for lower inductance motors, though only really Nema 23.
Either way the difference is insignificant if you're running the motor on a higher voltage with something like this:

http://www.zappautomation.co.uk/2m11...5669f8490a6970

Without that you'll never get a very high speed from that size motor, if you need it.

[fragger6662000]

i would go for this if i were to running higher voltages

http://www.geckodrive.com/g201-p-31.html

i have used similar drives to the one at zap for my first project and they are Chinese in origin and my experience was not good.

Gecko are US designed and built

[Jonathan]

You seem to be implying that just because it's not US designed and built it's not going to be any good? Maybe that's correct in some, or indeed a lot of cases but I'll bet they're getting better. I got my PM752 drivers, which are rated similarly to what you linked to and are Chinese origin, and can only highly recommend them:

http://www.zappautomation.co.uk/pm75...5669f8490a6970

Still, 75v / 80V is nothing compared to the 240V driver. I think Robin Hewitt used them on his mill?

Interestingly the Gecko driver says 'Silent 20kHz PWM switching'. I'm pretty sure I can still hear 20kHz, so that would be annoying!

[fragger6662000]

i bought 5 of the 4.2amp version and 1 failed.

I don't have an issue with chinese stuff but high voltage and currents i avoid from my previous bad experience.

Also i don't really trust anything that quotes PTP not RMS to boast there numbers. so the 5.2amp driver is only 3.7 when you get to 3.37 when you read page 9.

[Ricardoco]

Ok here is a question that im sure could have many answers, Ive looked at a few calculators in the past but I do prefer the opinions of those than can, rather than some calculator that Could...
Im going to wake up the boxford today and cut some bittlet, I will be using a 6mm 2 flute endmill (this is so I can do everything I need without changing the tool), what would you suggest for the feed rate and plunge rate with a spindle speed of 2000 rpm (it will do 3250rpm max) Im looking for quality rather than speed but I dont really want to watch paint dry for any longer than needed so a compromise will be ok.



Rick

[fragger6662000]

depends on what you are cutting and rigidity of the machine.

On my converted mill at 2000rpm in alloy i take 2mm DOC at 200mm/min

When i increase the sindle speed to 3000 i could take 3mm at 300mm/min

WD40 and GT85 make great cutting fuild for alloy

[Jonathan]

Assuming a slot 2000rpm with 2mm DOC at 200mm/min sounds reasonable (as long as there is some cutting fluid/coolant around), however the tool deflection is borderline so it may not get a good finish. I would use that then at the end do a finishing pass taking say 0.2mm off all round at full depth.

Since the tool is 2 flute use half the feed for plunging (i.e. it's as if it only has one flute), so 100mm/min. Maybe a bit less, see how it goes.

WD40 does work well, but I doubt it does the machine ways much good. If you don't already have any it's well worth investing in the proper stuff.

P.S. Get some 6mm single flute carbide cutters - you won't regret it! I've just been cutting 3/4" thick aluminium with them on my router at 540mm/min, but only 1mm depth of cut. It may well do more but I'm not going to risk it without coolant.

EDIT: I'm assuming 'cut some bittlet' means aluminium! Also the above depends on other factors, such as if it's a deep slot...

[Ricardoco]

depends on what you are cutting and rigidity of the machine.

On my converted mill at 2000rpm in alloy i take 2mm DOC at 200mm/min

When i increase the sindle speed to 3000 i could take 3mm at 300mm/min

WD40 and GT85 make great cutting fuild for alloy

Thanks Fragger The material is 6082 Aluminium Plate, the machine is very rigid piece of kit...

[Ricardoco]

Assuming a slot 2000rpm with 2mm DOC at 200mm/min sounds reasonable (as long as there is some cutting fluid/coolant around), however the tool deflection is borderline so it may not get a good finish. I would use that then at the end do a finishing pass taking say 0.2mm off all round at full depth.

Since the tool is 2 flute use half the feed for plunging (i.e. it's as if it only has one flute), so 100mm/min. Maybe a bit less, see how it goes.

WD40 does work well, but I doubt it does the machine ways much good. If you don't already have any it's well worth investing in the proper stuff.

P.S. Get some 6mm single flute carbide cutters - you won't regret it! I've just been cutting 3/4" thick aluminium with them on my router at 540mm/min, but only 1mm depth of cut. It may well do more but I'm not going to risk it without coolant.

EDIT: I'm assuming 'cut some bittlet' means aluminium! Also the above depends on other factors, such as if it's a deep slot...

Hi Jonathan, you and fragger seem to be of similar opinions on this so i will take those settings as a theoretical maximum, and do a finishing pass as well, ( If you don't already have any it's well worth investing in the proper stuff.
) I have.. Thanks for the input it really is much better than those calculators because they dont explain the 'Why' just the 'What'....

[fragger6662000]

personally i would only use single flute for plastics and as to reduce heat and chip recutting, i would go for a three flute high helix cutter and go deeper and faster as you get more continuous chip engagement.

in production we use 2 flute at 25000rpm at 6mm DOC at 8m/min