Re: [CAD_CAM_EDM_DRO] CNC drilling

----- Original Message -----
From: "Ron Ginger" <ronginger@...>
> What feed rates are used for CNC drilling? Do you calculate chip load
> like you would for an end-mill? What is a reasonable chip load for a
> drill? I suppose that varies by drill diameter?
>
> ron ginger
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In General, in mild steel or aluminum ... you can always be cautious, and
if nothing breaks over time go a little more.
The only penalty for going with too small of feed is that in steel, there
might be work hardening, and that might occur in feeds of less than 0.001
per revolution per flute .... in aluminum that is not so much of a worry, it
just makes the cycle time very slow.
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So, as a starter, go with 0.001 per flute per revolution. ( quick
conversion: 1 inch per minute for each 1000 rpm for a single flute. )
Also as a starter, only go 2 diameters deep before you pull out ( full peck
out/in ) to get fresh cutting fluid ( if it is used, mostly recommended if
in doubt. ) For deep holes, ( 5 or 10 diameters deep ) do a full peck every
1 diameter.
A little slower full cycle is still faster than removing a broken drill bit
!!!!!!!!
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With experience, you can get more progressive if you have lots of holes;
remember that small drill bits have very little actual core strength, ie
they break fairly easily; anything under 1/4 inch is a small drill bit.
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Note that 0.001 per flute per rev applies to almost any cutting tool. Also
remember than when the clearance flutes get full, the tool will probably
break. BAD BAD. ( Titanium breaks your tools not because it's hard; it
sticks to your tool and untwists your drill bits (g))....
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Hope this helps. ken campbell, deltawerkes