And most likely the only thing this guy has cut is his toe nails...
Have you ever CUT METAL??? worked in a Shop?? Served an APPRENTICESHIP????........ yada yada....
Come on Gary , give the lad a break, he is using his experience? blah blah...........
Crap guys...... ain't no slack for nobody, huh?
You all don't know him, how can you toss the judgement up front? Sound like grumpy old farts to me.
In my case, I personally had 6 years in a shop, lots of experience with several things. What CNC experience I had was on a prototrak and self taught. I switched jobs and worked with a couple guys that knew what they were doing on the CNCs, so it was a whole new game. I asked the main CNC guy if there was a way to calculate speeds and such. I was use to guessing going by how it felt to me for 6 years of mostly manual machining. He was happy to help and gave me a straight up answer, not like some grumpy dried up old pecker
here we go again........ Fast is not in the least bit important, how many you have made at the end of the day is
Actually, quality is far more important that quantity, or so many may agree.
hello all i want to ask a question to some ppl that will be able to answer this question once and for all. does anyone know of a good reference guide or chart for speed and feed rates based on tooling and material??? also i wanted to know what everyone uses for this. most the time i start out with an experienced guess and go from there. theoretically i would like a chart or grid that i look at that would tell me the max speed and feed i can use for the tool and material combonation, or better yet when i choose the tool in mastercam it already loads it for me. any help on this is greatly appreciated!
The only chart you need is a calculator.
Several years ago I was told, on steel:
100 SFM for high speed steel
200 SFM for plain carbide
I find with HSS, on tool steels and such, maybe as low as 80 SFM, mild steels, maybe as much as 120 SFM or so. Carbide can often run more than 200 SFM. Coated carbides might go for 300-600 SFM, you really just need to look for manufactures specs.
If you ask me, on aluminum, it's pretty much whatever the machine can handle. You can run 1000+ SFM easy with HSS endmills.
but you don't necessarily have to go as high as any of these speeds, or be constrained by them. Keep in mind that this is best with flood coolant.
To calculate RPM:
RPM=(3.82*SFM)/DIAMETER
say 1/2" HSS endmil on mild steel
(3.82)*(100)/(.5)= 764 RPM
Feeds are hard to be straight forward, way to many variables. It can range from less than .0005" per flute to more than .010" per flute. It is easy to start with around .002" per flute.
Calculate as:
FEED=(RPM)*(# of flutes)*(FEED PER FLUTE)
Say from the above speed....
(750)*(4)*(.002) = 6 IPM
And that should be fairly mild. And these are better for less than 50% width of cut.
But keep in mind that there are MANY variables. Spindle HP, machine rigidity, tool quality, coolant quality and depth of cut, width of cut. If spindle RPMs high and HP is low, cutting .008" per flute can turn into .012" per flute real quick as it bogs, and gets worse till it backs up on max torque or stalls.
Cutting full width you will likely need to back off a bit. Cutting deep you sure might need to. But these should get you a starting point. All just depends on machine, tool and material.
If you tell me this is on some little POS benchtop mill, I'll ringe your neck for wasting my time and tell you to burn it and throw it out in scrap. Just because they are shit and makes these calculations useless. Cause even a beat to piss, neglected, worn out 40yr old bridgeport still be 10x better than a worthless little benchtop