I'm starting to lose my mind - Can't mill a simple pocket

[beni17nexus]

I'm starting to lose my mind, because of this pocket. And this is not even the hardest operation i have to do, just look at that 30 degree incline...

First when I tested the model with only one "circle assembly" the pocket milled out great, but the mill broke working on that incline. Since that I couldn't mill it out. First my endmill broke as soon as the endmill touched the stock. Next I reduced the helix angle to 1 degree and held the feed back to 60%. It milled out half way but broke again. The problem is that the gap between the incline and the cylindrical extrusion is 2.047mm. My tool is 2mm in diameter so it's a tight fit, but it should work. I'm using 2d pocket operation with the settings attached. Could you recommend some settings, feeds and speeds? Or maybe could you recommend a better operation which can mill out the complete pocket with the incline too. Moreover if we can get the pcket milling to work, what operation and mill do you recommend for that incline?

Please help me if you can because it seems I can't figure it by myself and i'm breaking a lots of endmills.

[LibertyMachine]

Can you attach the Fusion F3D File, that will give us your toolpaths

File > Export > Save to local folder. Return to thread and attach the .f3d file in your reply

[beni17nexus]

Here's the file. 

[LibertyMachine]

And what is the machine and the material?

[beni17nexus]

Machine is a custom built 3 axis cnc milling machine. You won't recognise
it by name, but it is made in EU and its a professional industrial grade
one. Material is simple st35.

[Anonymous]

i had this, i ended up adding mulitple depths and going at .5mm . i could go 1mm very easily but 12 bits later at £4.50 each it gets expensive.

[beni17nexus]

I used 0.5mm depth of cut with multiple passes. Thats how my last endmill broke.

[LibertyMachine]

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@beni17nexus wrote:
Machine is a custom built 3 axis cnc milling machine. You won't recognise
it by name, but it is made in EU and its a professional industrial grade
one. Material is simple st35.

---

The goal of my question is to determine if you are working with a rigid commercial machine or a more delicate "hobby" machine. Spindle horsepower and max rpm? Do you have coolant?

[Anonymous]

think i'm going senile , i'm sure i posted a question just before i answered yours here.
what mills are you using?

[beni17nexus]

Its a rigid commercial machine. 8.5kw 8000/min

I'm using a 2mm diameter hss co8 2x7mm flute endmill for this pocket.

Maybe this is the problem. I ordered some carbide endmills with TiALCN coating.

[beni17nexus]

Im using flood coolant with a 4bar pump. Coolant is Loctite LB 8035

[beni17nexus]

See tha attached photos of my current progress without the pocket and the incline, also my setup and machine.

I the red circles you can see where my endmills broke. 

[LibertyMachine]

I would certainly go for carbide tooling. I don't know if Harvey has a European prescence, but they make some phenomenal long reach tooling. For roughing, you don't need something with 7mm of flute, but rather just something with the reach needed. http://www.harveytool.com/ToolTechInfo.aspx?ToolNumber=37178-C3

Perhaps there is a tool manufacturer that offers something similar where you are at. They aren't cheap, for sure. But, tool life and reduction in frustration certainly make up for it.

That said; You are running that tool a little bit heavy. I'd favor 100-125 sfm, which would give me a spindle speed of 6k and a chipload of .0001" per rev or 45.7 mm/min

Switching over to carbide will GREATLY reduce your overall machine time. Right now you are coming in at 3 hours, 45 minutes of that is spent on the adaptive cut. No reason that can't be brought into the 3-5 minute range

[Fueler]

Carbide 4 flute at the minimum for sure.

Based on my own self induced problems I suspect you have a lot of tool deflection which breaks end mills.

Slow down feedrate and/or lead in feedrate?

Oops, what Liberty said.