What is climb milling?

[MarkLong]

What exactly is climb milling?

Posted this message on the old forum but thought I'd try out the new forum.

With the ability to put photos in your bio I may have to comb what little hair I have left.

[Harold]

Climb milling is when the material to be milled is advanced in the same direction that the cutter is rotating. In other words, you are not feeding the material into the cutters teeh face, but rather into the back side. In certain setups/materials, this can cause chatter, or worse yet, "grab" the workpiece and gouge or jam it into the cutter OUCH!

[ttyR2]

As Harold said, climb milling can be dangerous, but it also produces the best finish as the cutter isn't recutting chips but ejecting them instead. I use climb milling a lot on aluminum, but only with small cutters in my old Jet16 mill/drill. I wouldn't try it with any larger cutters (1/4" is the max I use it with.)

[Davey]

climb milling sometimes produces a better finish, but not always . it can also cause your tool to get sucked in to the workpiece breaking the endmill or even worse ruining your workpiece.You can climb on a bridgeport type mill roughing if you take at least 2/3 of the cutter diameter.Although I don't recomend it,unless you have the experience .Ive made climb cuts with the table locks engaged slightly for security,but this is not good for your locks ,in a pinch it will work.

[gezr]

a cutter cutting full diameter is neither cutting climb or conventional since both happen at the same time.
once that slot is cut a choice to make it larger would require a choice as to wether climb or conventional direction of cut relative to the rotation, conventional cut lets a flut on the end mill to start cutting at the edge of the new slot and cut up from there to the first initial slot. cliimb milling would have the cut start at the old slot and finish the cut at the side of the new desired width and with each advance climb one more step up the direction of the cut.
You could describe this action as walking. if you lift your foot and put it down then pull yourself forward thats climb milling, if you slide your foot forward thats conventional milling.

[itspcb]

Here's a pic from a book showing the difference. The interesting point is why it is so difficult to climb mill. There are a few issues. In Normal milling on a machine, with no backlash control, the cutting action forces always loads the machine table in the way it was designed to resist them. In climb milling the action is try to push the table away from the resisting system. Also the diagram shows the different way the chips are formed . In the normal way the chip starts thin and builds up the load as the chip gets bigger, no big starting load. In climb milling the chip starts big giving heavy load to the machine. Having said that as was pointed out previously climb milling does leave the milled surface untouched, whereas the normal method continually remachines the surface. Some folks take advantage of this with light finishing climbing cuts to get a better finish. Some folks have mills that have backlash control systems that means you can mill either way. Some say that with a proper backlash system you can remove metal faster by climb milling, but I don' know why.

Peter B
UK

[Al_Messer]

Now I know why I like using a shaper so much!!