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

I agree with the other comments and would consider if you have no slower spindle speed, to make the material very secure to the machine. Any vibration (up & down) motion will effect the finish the tool will provide. I would not consider any HSS (high speed steel, coated or uncoated) because of the spindle speed. Mist spray system is mandatory, heat is an issue, in addition the air blast will keep the chips out of the way. Think about this end mill, cutting on the side of the tool, when the tool (end mill) re-cuts a chip it drags it against (pinching the chip between the tool and part, until it cuts thru) the part (creating poor finish) and on a carbide tool it will chip (extremely fine) the cutting edge of the tool, affecting the finish and tool life. If using spray mist system use plenty of air to keep the chips clear of the tool and to cool the tool.
If you are not able to find cold rolled steel (this is hot rolled steel re-processed in the cold state) the scale on hot rolled steel can be abrasive. Usually if I am going to cut hot rolled steel I will ruff, with old tool and save new tool for the final cut so to get best finish (on aluminum as well) on the part. I may take a 9" grinder to cut thru the scale on steel flat plate, this saves the tool, depending on the part you may not choose this.

When you think of number of flutes on the tool, the more flutes = more sharp edges but less room to get rid of the chips. So longer tool life with more flutes may not cut in the center, center cutting end mills are necessary if you want to plunge (use like a drill bit, a common use) usually 2 and select 4 flute end mills have this option, when you look close at the cutting end of the tool, you will see the differences.

On aluminum (6061-T6 cuts better than others) but if no coolant the chips can pack up (the chip welds to the tool, not allowing the next chip to cut, resulting in tool breakage) and use air to keep the chips out of the way. There are some coating on carbide that end mills that help to reduce welding of the chips to the tool. Best of luck!

new2linux wrote:

I agree with the other comments and would consider if you have no slower spindle speed, to make the material very secure to the machine. Any vibration (up & down) motion will effect the finish the tool will provide. I would not consider any HSS (high speed steel, coated or uncoated) because of the spindle speed. Mist spray system is mandatory, heat is an issue, in addition the air blast will keep the chips out of the way. Think about this end mill, cutting on the side of the tool, when the tool (end mill) re-cuts a chip it drags it against (pinching the chip between the tool and part, until it cuts thru) the part (creating poor finish) and on a carbide tool it will chip (extremely fine) the cutting edge of the tool, affecting the finish and tool life. If using spray mist system use plenty of air to keep the chips clear of the tool and to cool the tool.
If you are not able to find cold rolled steel (this is hot rolled steel re-processed in the cold state) the scale on hot rolled steel can be abrasive. Usually if I am going to cut hot rolled steel I will ruff, with old tool and save new tool for the final cut so to get best finish (on aluminum as well) on the part. I may take a 9" grinder to cut thru the scale on steel flat plate, this saves the tool, depending on the part you may not choose this.

When you think of number of flutes on the tool, the more flutes = more sharp edges but less room to get rid of the chips. So longer tool life with more flutes may not cut in the center, center cutting end mills are necessary if you want to plunge (use like a drill bit, a common use) usually 2 and select 4 flute end mills have this option, when you look close at the cutting end of the tool, you will see the differences.

On aluminum (6061-T6 cuts better than others) but if no coolant the chips can pack up (the chip welds to the tool, not allowing the next chip to cut, resulting in tool breakage) and use air to keep the chips out of the way. There are some coating on carbide that end mills that help to reduce welding of the chips to the tool. Best of luck!

very helpful and informative

Yes

This steel seem to be very hard. I will check with the supplier and I will try to get less harder material.

 


Philip