So you believe that metal removal rate has no effect on tool forces. The graph shows that it does with the varying feedrates ( increased feedrate shows an increased tool load ).No, it shows that slower surface speeds produce higher cutting forces for an equal depth of cut. Which is exactly what happens as you part off a piece at a constant spindle speed, as the diameter decreases the cutting force will increase of the depth of cut remains the same. Sounds like exactly what happened to the parting tool in the original post.
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So you believe that metal removal rate has no effect on tool forces. The graph shows that it does with the varying feedrates ( increased feedrate shows an increased tool load ).
The tool in the example broke " very quickly " which I read as near the outside diameter where the cutting speed was near ideal.
Let's address the initial post. Parting 316 stainless steel without coolant breaks tools. Parting 316 stainless steel without coolant and with a dull insert previously used without coolant, always breaks tools. This is the overriding cause for the tool breakage in this example. I'm sure we can all compile a list of other minor contributing factors.Actually, if you read post #9, the cut was about halfway through when he began to have issues. This is right around the time that SFM is beginning to drop and tool pressure starts to increase.
Parlo, please show us your formulas for MMR so we can all attempt to see where you're coming from.
Let's address the initial post. Parting 316 stainless steel without coolant breaks tools. Parting 316 stainless steel without coolant and with a dull insert previously used without coolant, always breaks tools. This is the overriding cause for the tool breakage in this example. I'm sure we can all compile a list of other minor contributing factors.
Aukai used cutting oil from the get go. Not sure if the insert was new but coolant was used throughout so no, I don't agree that this was the cause of tool breakage in this instance. As I have stated multiple times, I believe it was due to the cutting conditions that developed as the cut was made. It was not the blade. It was not the insert. I have parted 303, 304 and 316 on numerous occasions with a used GTN-3 insert without any issues. I have parted SS even more often with HSS and I know those blades were often not freshly sharpened and I had no issues parting with them, either. The difference between Aukai and me doing it was that I controlled the feed manually, that's all. No problems, no chatter, no crashes, no stalling.
I will leave further discussion to you and others. I wouldn't want you to injure yourself trying to simplify things for me or have to scour the net for articles to reinforce your point. But I do congratulate you, Parlo, for being the single person to have made my Ignore list.