Milling out a V shaped part

[pelseyHYPS2]

I have been making this part attached for about 6 years. I inherited the part and it is one of my biggest headaches in terms of machining. I have a 3-axis mill to do this part on. 4 or 5 axis is not an option 

The issue is the part has a standard 1.5" NPT thread on the one end almost to the bottom of the V. So no extra stock to grip on the sides  (note I didn't draw it in this file) and holding it is a pain in the butt. It is threaded fully before I mill it. I have made a tapered pot chuck to fit these pieces but I know it is not the best way. I have ordered an manual ID clamping fixture to help address this issue. After talking with my tool rep he suggested trying a 1/2" or 5/8"- 5 flute ball mill. I am down for this because currently we use some chamfer mill to hog out the center then a 60 DEG chamfer mill to get the angle on the sides right. Like I said earlier, I inherited the machine, job and programming so why it was done this way I will never know. When the piece pulls out of the chuck it will smash the very expensive chamfer mill we were using. 

My tool rep was hoping switching to a carbide ball mill with 5 flute would help reduce some of the forces on this part. I have never done anything with a ball mill and I am not sure what is the best way to program it. Currently we just run a straight pass thru the center end to end at three different heights. Again, not the best way I know. So I want to profile it using this ball endmill but I am not sure what the best selection is under the 3D machining tab. I currently have selected is "Morphed Spiral" but I am not sure that is what I want being I have zero experience with ball endmills. 

Can someone look at this any give me their opinion on this? I know how I want to finish it, I am just trying to reduce the load on the tool that pulls the part loose. Minimal stock removal at the end is preferred  

I have attached the whole file at the end. 

[seth.madore]

Lol at your tags 🙂

There's no dumb questions here, we all start with zero knowledge of how to do stuff in Fusion.

What are you looking for in the root of the "V"? Do you need that sharp corner? What's the material? You mentioned an NPT, I assume that's on the OD?

[pelseyHYPS2]

Just being honest on the tags lol. 

To answer you questions: 

1) The root of the v is not of concern. I have an endmill I run at the end to clean that up. Same with the 60 deg on the sides. I just want to hog out as much material as I can with this ball mill. 

2) Yes the corner will be sharp at the bottom when done. Same thing on sides. These parts get welded on for an oil drain. We usually just hand deburr whatever the machine fails to cleanup because.... pipe sucks. 

3) Material is just a standard carbon pipe. I always say its 1018-1020 material for programming purposes.

4) Yes the NPT thread is on the OD at the bottom. 

[seth.madore]

And your 3-axis machine; stout or home use sized? Coolant, RPM capacity, tool changer?

[leo.castellon]

I get this error when trying to open  your file, not sure what is going on; 

LeoC

[seth.madore]

Yeah, I ran into the same. For some reason, it's actually an .f3z file that needs to be uploaded to your Data.

[pelseyHYPS2]

Coolant.
Rpm capacity is 8100rpm

[seth.madore]

I'd suggest using a 3D Adaptive toolpath to rough out from tub stock, but the ball endmill is not likely going to be the best choice for this. Are you opposed to bull nose endmill?

For holding, are you in a 3-jaw chuck? Have you considered threading the jaws so it's holding onto even more material?

[pelseyHYPS2]

I will try that. Never got too much into the 3D side on fusion yet. 

I'm currently holding the piece in a homemade pot chuck and then closed in some soft jaws in a kurt vise. It's tapered to match the taper of the thread. I would thread it but the pot chuck has cuts through it to make spring like. It's quite a sight of redneck ingenuity lol...

Hopefully the ID jig I am making currently making will fix my fixture issues 🙂 

[anthony.a.douglas]

I have used ball mills  an number of times.  The main issue is that the cutting hardly happens towards the center at the tip, but the same applies to a chamfer mill.   Otherwise you just have to start slow and experiment.  I don't think reducing cutting forces is a good approach to reducing a fixturing failure in this instance, it's going to be just as much work, a bit unreliable as the forces change with cutter sharpness etc.  Sounds like you pretty much have the problem under control with your new ID fixture.  Why can you not simply make a large hole in a block of aluminum, taper thread it with e.g. a single point thread cutting tool, screw the pipe in there real good and then clamp the block of aluminum down?

[pelseyHYPS2]

Actually I was able to get it with some creative programming on a ball mill that is miles ahead of what the other guy did. More cost effective too. Better fixture I came up with too. Thanks everyone! 

here’s a picture 

[leo.castellon]

You are keeping us in suspense, where is the picture? 😁

LeoC

[pelseyHYPS2]

 oops didn’t realize it didn’t load the picture! 

[leo.castellon]

Good job!

LeoC