Spiral or Dynamic?

[Newbeeee™]

Hi All,

We got some mild steel (low carbon) billets to do.

7" dia with a shallow recess in (5" dia x 1/8" deep).

Rather than bore the recess on the lathe, I wondered about milling it out (as there are also some PCD holes in the same face).

So after having good results with peel milling and reading a bit about dynamic milling, I'm thinking of using either dynamic or spiral mill with a small stepover.

I'm leaning towards spiral but can anyone advise on tools/stepover/speeds and feeds please?

Cheers

[Josh Kinney -Elite Engineering]

I would 2D Contour Ramp using a 2" Mitsubishi AJX and then come in with a 5-7 flute endmill to finish the walls. On the AJX probably 350-500SFM, 0.035" FPT, 0.039" DOC

[MotorCityMinion]

A little off topic perhaps but I don't think your going to beat the lathe for speed or tool life.

[Chris Rizzo]

I'm doing a bunch of bores right now with dynamic mill. Set entry to helix, full depth, and then the usual 10-15% step over, at about 300ipm. Works great and the machine is just so smooth.

[kunfuzed]

I've always been curious about this. When and where does a lathe or mill beat the other at pulling off cubes.

[jeff]

quote:

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When and where does a lathe or mill beat the other at pulling off cubes

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In this case you can't beat the lathe.

 

The lathe can remove material faster than the mill can in MOST cases if programmed right.

I ran cnc lathes for 15 yrs before I made the switch to mills and there is no comparison.

[jeff]

If the lathe isn't an option, grab a 2" facemill and spiral it out to 5" and finish the walls with an endmill as mentioned above.

[Mgrenier]

I would use a 2-1/2" inc cutter and use contour ramp to full depth in 1 shot and then do the flat bottom. This means you have 2 cicles to do and 1 little linear move to remeve the material left by the corner radius of the cutter. You can then use an endmill afterwards if needed for the finishing.

 

JM2C,

[Newbeeee™]

Thanks for all the replies.

The lathe is maxed out at the moment, so I thought we'd use the mill.

Thanks for all the suggestions.

Cheers

[MotorCityMinion]

"The lathe can remove material faster than the mill can in MOST cases if programmed right."

 

I know of shops that will build fixtures to face and bore almost any casting on a lathe, assuming that the quantity justifies it. I've seen some very odd shapes tooled up like this and it works great. Think about it: The part doesn't have to be round to spin, and you can often finish more geometry on a part with fewer tools in a much shorter amount of time than on the mill.

 

Newbeeee, post back and let us know how it went.