Slotting And Direction Of Cut?

[RVJimD]

I am working on track pads for a model dragline crawler undercarriage. I cut the wide slot in one pass using a 3/4" end mill. This is 6061 and the depth is 1/4". It made me question wether there is any difference in the direction of the cut like there would be if I were side milling? What if this were a pocket? I did just barely snug up the gib lock to make sure it was steady. Also tried to reduce the size of the photo to improve loading speed. Hope it isn't too grainy.



Jim

 

[f350ca]

Direction in an operation like that doesn't matter Jim, your not climb milling from either side.
Just as a note, for accuracy of width, its best to plunge through as you did with say a 5/8 cutter then step over and cut the shoulders to width. Same as when cutting keyways. A 3/4 cutter will rarely produce a 0.750 slot. The cutter may be slightly under or over sized and slack in the quill spindle bearings or gibs will cause it to shift.

Greg

 

[dracozny]

It's advisable to use an end mill with as few flutes as possible, a 4 flute cutter will walk to one side of the other as it attempts to climb cut against the other side. An undersized cutter is also a good idea to cut the slot making one pass directly down the middle of the slot, and then two more passes by conventional milling to widen the slot to the correct size.

 

[randyc]

In addition to the fine advice above, try to keep the slot clear of chips with a vacuum wand. This will produce a better finish by avoiding re-cutting the existing chips.

 

[chips&more]

Direction in an operation like that doesn't matter Jim, your not climb milling from either side.

Greg

And why are you saying that? If you plunge the end mill it will be climb milling on one side and conventional on the other side of the slot…Dave

 

[f350ca]

Same thing only reversed if you come in from the other side on the initial cut.

Greg

 

[T Bredehoft]

A little background, probably not needed.

Climb milling has been frowned upon forever, (CNC and ball screws have obviated this problem.)
When you crowd a four flute mill through a cut, there is always one flute which is pushing the entire cutter to it's left, causing the incoming (regular cut) to be deeper than if it was a two flute cutter. Two flutes will cut very near size. But it's usually best to use at least three passes for a cut, one down the middle and two regular cuts on the sides to cut to dimension.

Tom