what is the max feed rate using 3 mm bit on mild steel?

Good day

I have conducted many calculaters on the net, but my question is for people with real life experiance.

assuming 3mm end-cut bit,   0.1 mm stepdown, and 6000 rpm(The min safe spindle rpm)

what is the feed rate befor I break the bit.

Philip

Thanks

i'd try 3 inches per minute. lots of coolant
good luck

Thanks

Then no wonder the bit broke with me

I ran much faster feed rate, and it snaped very quickly.

This is my first milling attempt for steel ever.

I will use a biger bit tomorrow ( 1/4" ) and reduced feed rate(50"/minute). Unfortunatly, I can not take the rpm below 6000-7000 rpm, so I will have to reduce the stepdown. I will try 0.05 mm. I know that is not practical, but since this is the first run of the machine, I need to test the water.



Philip   

 

i cut aluminum all the time. i use a 3/32" mill and run it at 4200(max Speed)
and 4 inch per minute , at a .05" depth. only break mill when wore out. if you use a 1/4" you should be able to go to .1" deep like you wanted. but i would still go 4 inch per minute. sorry, i can't convert luck !

thank you

now I have a referance


I will go 4"/min and slightly push the feed rate up to see the limit

Good Luck

i use 3 flute .125",3/32", 7/64" mostly. and i ONLY cut aluminum. yes metal is different and i agree, a whole new beast. all end mills are 3 flute and carbide.
i prefer 3 flutes. stronger than a 2 or 1. i was only giving him a start.
and thank for your reply tommy

tommylight wrote:

1, 2, 3, or 4 flute?
1, 2, are for alu, 3, 4, for metal.
HSS or HSS+CO or Carbide or TiAlxxx?
What is the chip load on the end mill?
all those are required for successful cutting on metal.
You can get away a lot when cutting wood, you can get away a bit when cutting ALU, but metal is a different beast.
Yeah, also what metal?
Disclaimer:
I have no clue about milling metal, those are info i gathered reading mostly and milling rarely.



 

I will check the number of flutes tomorrow

most likely 2 flutes and have yellow quotes ( I think titanium)
I am cutting 8 mm thick carbon steel sheet
the material is just plain carbon steel sheet. I want to cut squares and circules

I already cut wood very clean cut. and I want to see if the machine can cut steel.

If I face vibration or other issues, I will may have to beef the machine further, but eventualy I will make it work  

Best regards

Philip  


 

I just want to report that the machine is able to mill steel with very reasonable capability under the current situation.

there is little vibration that come briefly  then go.

Taking into consideration that the rpm is 7000 rpm (Spindle designed for wood milling), where the book says the rpm should be around 1500, and taking into consideration that I did not set the cooling water yet. The possibility that I will have a major issue when I finalize the machine (After  I install the bt-30 spindle and the cooling water ), the possibility that the project will fail is very small.

So my next step is to weld the stiffining braces, have a new front plate designed for the bt-30 spindle and the driving motor.

That will take a couple of months maybe more.

I used 4mm bit
feed rate : 180 mm/minute
step down 0.075 mm

I know that is limited capability, but the rpm is limiting me.


Philip