MRR refers to a volume per unit of time. Feed rate x depth of cut only gives an area. Turning a diameter on a lathe needs the area of the cross section x the feed rate to give the volume per rev. ( Like a stack of washers with each one the thickness of the feed per rev ). When facing, the cross section is continually reducing.MRR = cutting speed x feed rate x depth of cut, right?
Which of those change when facing or parting on a manual lathe with power feed?
MRR = cutting speed x feed rate x depth of cut, right?
Which of those change when facing or parting on a manual lathe with power feed?
Okay, instead of some nebulous contentions about MMR that you were proposing before, now you seem to be stuck on the idea that coolant alone would have prevented any breakage issues that occurred. You have a tool that is being forced into a cut that it cannot make so it breaks. That is clear for all to see. I tried to explain it but you continued to insist that some force that I am too stupid to understand is responsible. Until today. Today, its not that force; its coolant, but only if its flooded. Really?There is a significant difference between cutting oil and coolant, especially in this instance. Cutting oil was manually applied, not flood coolant as I suggested. The insert had cut one previous part without flood coolant. The cutting conditions did develop / deteriorate as the cut was made, due to the lack of coolant.
Let me be crystal clear. I am "vexed" because of your veiled insults, Parlo.You seem rather vexed if your opinion is challenged. A forum is for all to exchange views, not a competition.
Same as parting.............MRR refers to a volume per unit of time. Feed rate x depth of cut only gives an area. Turning a diameter on a lathe needs the area of the cross section x the feed rate to give the volume per rev. ( Like a stack of washers with each one the thickness of the feed per rev ). When facing, the cross section is continually reducing.
Hope this helps.
MRR refers to a volume per unit of time. Feed rate x depth of cut only gives an area. Turning a diameter on a lathe needs the area of the cross section x the feed rate to give the volume per rev. ( Like a stack of washers with each one the thickness of the feed per rev ). When facing, the cross section is continually reducing.
Hope this helps.
Yes, facing and parting are the same when referring to varying stock removal rates.Same as parting.............
Yes, my comment #52 split the speed into its two components - distance and time. I used the distance to multiply the area to give the volume. The distance i.e. the circumference, reduces as the cut proceeds towards the centre and therefore the volume decreases.If we have an area and we need volume per time, don't we need to multiply by a speed (distance per time) instead of a cross section (area)?
Okay, one last time.
Okay, instead of some nebulous contentions about MMR that you were proposing before, now you seem to be stuck on the idea that coolant alone would have prevented any breakage issues that occurred. You have a tool that is being forced into a cut that it cannot make so it breaks. That is clear for all to see. I tried to explain it but you continued to insist that some force that I am too stupid to understand is responsible. Until today. Today, its not that force; its coolant, but only if its flooded. Really?
Let me be crystal clear. I am "vexed" because of your veiled insults, Parlo.
Don't even try to put me in a position where I seem to be the inflexible authoritarian. Not only is that totally inaccurate, it makes you out to be the poor wronged martyr and absolves you of having any part of this - I'm not having it. If anything, we are here because of you. I have been a member of HM almost since the day it was created and my record of exchanging views is there for all to see.
So is yours.
He was only referring to cutting speed.From the article Mikey posted. Specifically, the article is talking about parting:
"If the machine tool’s spindle speed remains constant as the parting tool moves to the center of the workpiece, the cutting speed will gradually decrease until it reaches zero at the center. A decrease in cutting speed is disadvantageous for the tool and can severely stress the cutting edge. As the edge approaches the center, pressure increases as the tool is fed at the decreasing cutting speed."
Author
Scott Lewis
Scott Lewis is with Sandvik Coromant Co.
So, if the spindle speed and the feedrate are constant, then it stands to reason that the material removal rate and surface speed are reduced as well, as the tool plunges deeper.
Yet still, it says that In that scenario, the pressure would increase as the tool moves toward center.