Still Confused with Conventional and Climb Milling

[higgite]

Deleted. Sorry.
Note to self: Never type before coffee kicks in.

Tom

 

[RJSakowski]

I think one of the confusing issues is what is the direction of feed. The Harvey paper shows the direction of feed as the direction the cutter is moving relative to the work. When we feed with a mill, the cutter is stationary and we feed the work into it. The two are opposites. It doesn't help that in some of the illustrations, it isn't clear which is being referred to.

 

[WarrenP]

How can you climb mill when there is little or no material to cut when slotting ! Yes the tool will rub and the trailing side will get polished.
The Harvey tool post explains it well, but unfortunately doesn't deal with slotting.

It seems to me that when cutting a slot by the illustration above you can see that the conventional cutting side is only cutting one side of the slot and the climb cutting side is cutting the other side of the slot. How else would the "climb" side be cut to size without that side cutting also? The "conventional" side doesn't touch the other side.

 

[BaronJ]

Hi Warrren,

Get a lump of material and try it for yourself. Start cutting a slot. There is no climb milling at all ! Now back out of the slot you have just cut, ignoring spring, no material will be removed. When you back out you will be moving your cutter in the climb milling direction !

Now if you have a machine with a worn spindle or a worn table, there might be enough slap to cause the cutter to rub more heavily than it might.

 

[higgite]

That illustration is a little misleading when we're talking about slotting because the cutter is shown in the middle of the slot lengthwise. That's not how a slot gets cut. When slotting, regardless of direction of feed, each flute/cutting edge will enter the cut as conventional milling and exit the cut as climb milling. You have no choice like you do when you're cleaning up a slot or widening it with a smaller end mill.

Tom

 

[ThinWoodsman]

Just a quick thought experiment.

Let's say you're conventional-milling the edge of a plate. You decide to use the entire diameter of the cutter (instead of 1/3 or 1/2 or whatever your personal rule of thumb is) in order to remove more metal in fewer passes, despite all the noise. Unfortunately you move the cutter too far inwards and have left a web of maybe 0.05" on the outer edge of the plate. You are now, in fact, cutting a slot.

At what point does it stop being conventional milling? Maybe when 1/2 the diameter of the end mill is cutting?

 

[BaronJ]

Hi ThinWoodsman,

It doesn't ! Cutting sideways into a surface is always conventional milling.
Cutting an edge traveling in the same direction as the cutter is turning is climb milling.

Using your example:
Once you start to move the cutter into the workpiece, the area of the cut increases until the full tool diameter is reached !
Once that happens you are right, you are now cutting a slot. The whole diameter of the cutter is now removing material, there is no material left to climb mill.

 

[mikey]

True that all of the cutting is in the 180 degree arc on the leading half of the end mill. but it seems to me that the cutter is conventional milling as the cutting edge enters the arc and climb milling as it exits the arc with a transition in the middle. Maybe that’s why it’s called slotting instead of conventional or climbing? Those terms do apply when the sides of the slot are being cleaned up or the slot is being enlarged with an end mill smaller than slot width.

But, I could be wrong. I was once.

Tom

I'm with Tom and @P. Waller here. It makes no difference what you call it. When cutting a slot with the end mill fully engaged, the end mill is cutting in both conventional and climb modes at the same time and it cannot do anything else.

Most of us rarely do a full width cut unless we just need a slot. If it has to be an accurate slot with decent finishes then we will use an undersized end mill to rough it and come back with a finishing end mill to climb or conventional cut the sides and ends.

 

[ThinWoodsman]

Hi ThinWoodsman,
It doesn't ! Cutting sideways into a surface is always conventional milling.
Cutting an edge traveling in the same direction as the cutter is turning is climb milling.

That was my thinking too. But that scenario helped me put the problem in perspective

 

[higgite]

I’m going to go out on a limb here and say that the terms conventional milling and climb milling only apply to side milling and that slotting is neither conventional nor climb. It’s slotting. And that's what I'm going to call it.

Now that that’s settled for all time. What is plunge milling, conventional or climb?

Tom