Milling machine - cutting speeds and feed rates

[Luke]

Hi all,

The Bridgeport is getting to a point where it's usable, I've been doing some research in to cutting speeds and feed rates. Numbers on the internet seem to vary massively.

Can anyone point me to trustworthy figures, or give me an idea based on experience?

I'm using HSS tooling on mild steel for practice. Numbers for aluminium would also be useful.

Thanks,

Luke

 

[madkayaker]

Practice away and you will soon get a feeling

 

[Luke]

I've done a few test pieces and the work looks like the cutter is 'ripping', I don't know if this is due to lubrication issues, spindle too fast, too slow, feed rate too fast, too slow etc.

 

[madkayaker]

Try slower feed rate or faster tool speed. I will try and dig out the chart that college gave me when doing my nvq

 

[Lawnmowerboy]

What tool are you using? End mill face mill?

 

[Luke]

I've got a selection of end mills and slot drills to start with, over a range of 6mm to 16mm, off the top of my head.

 

[piman]

Hello Luke,

the figures I remember from college were 80 ft/min for hss on mild steel and 1000 ft/min for aluminium. I know the latter sounds fast but that what I remember? I don't remember the feed rates but that varies with the cut depth as well.

Alec

 

[Lawnmowerboy]

Are you using proper coolant and how bigger cuts are you taking?

 

[Luke]

I don't have any coolant set up yet - it's on the to-do list. 1 step at a time etc.

Small cuts, perhaps 0.5mm.

Alec, I make 80 ft/min 24.4m/min, which is interesting, compared to a Google range of 30-38 m/min. Maybe I'm cutting too fast.