Looking for some help with speeds and feeds and end mill selection for milling 1/4” soft aluminium- guessing it is 3003.
Thx.
The only thing I can find at sienci is the good old fns datasheet for the longmill.
Don’t know if using a router table or a drill press works with this data sheet, but it at least is something to work with. I would advice against using a milling bit in a band saw though. It will probably fly off or jam your machine.
Hope you have some use for this datasheet in combination with your mystery machine.
Please be careful!
Usual preface, I’m with PreciseBits. So while I try to only post general information take everything I say with the understanding that I have a bias.
Without knowing the grade I would try no less than a 0.0015" chipload. Without knowing the grade AND tool I’d stick to around 600 SFM. What that means in actual cutting is ~9,000 RPM (RPM = (3.82 * SFM) / Diameter) and a MINIMUM of 27 IPM for a 2 flute cutter (Feed = RPM * Chipload * Flutes). Cut your pass depth down to something ridiculous to start out at (<1/4 tool diameter). You can increase this as you go but it buys you a lot of forgiveness.
The reason for this is that you are probably more likely to have issues with melting and choking the tool than anything else. In fact if you have the machine and tool rigidity it’s actually much easier to cut harder grades of aluminum.
Some other general things.
Make sure that the tool you are using has as short a cutting length as possible as you need the tool rigidity.
Do NOT use something like double sided tape to hold down the material. You need something rigid so the material can’t float back and forth while cutting.
Any runout that’s a significant portion of that chipload with probably screw you. It will make some of the cuts actually take a smaller chipload that will again melt the material. You can bias that by increasing the chipload (feed) to cover for it as long as the tool and machine can resist the larger cutting forces.
Not knowing the grade makes the whole thing a “at your own risk” scenario. You could have something with lead or bismuth in it (free machining). Those want even more chipload or they will melt.
I hope that marginally useful. Let me know if there’s something I can help with.
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