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General Mach Discussion / Re: Peck Drilling....
« on: December 31, 2009, 01:48:24 PM »Hi again Ray,
I have written an amended version of my high speed pecking macro, which allows for variable pecking as the hole deepens, using your rule of thumb as per previous post.
A debug print of the internal lookup table it creates, shows the results when drilling a ridiculously deep hole with a 4.5mm drill in simulation
4.5mm drill 600 RPM MaxPeck 4.5 MinPeck 1.5
Hole depth 51mm
Once either MinPeck is reached or 50% of original RPM, values are capped
Entry 0 Peck mm 4.5 Speed 600
Entry 1 Peck mm 4.5 Speed 600
Entry 2 Peck mm 4.5 Speed 600
Entry 3 Peck mm 4.05 Speed 570
Entry 4 Peck mm 3.64 Speed 541
Entry 5 Peck mm 3.28 Speed 513
Entry 6 Peck mm 2.95 Speed 487
Entry 7 Peck mm 2.65 Speed 462
Entry 8 Peck mm 2.39 Speed 438
Entry 9 Peck mm 2.15 Speed 416
Entry 10 Peck mm 1.93 Speed 395
Entry 11 Peck mm 1.74 Speed 375
Entry 12 Peck mm 1.56 Speed 356
Entry 13 Peck mm 1.5 Speed 356
Entry 14 Peck mm 1.5 Speed 356
Entry 15 Peck mm 1.5 Speed 356
Entry 16 Peck mm 1.5 Speed 356
Entry 17 Peck mm 1.5 Speed 356
Entry 18 Peck mm 1.5 Speed 356
Entry 19 Peck mm 1.5 Speed 356
Entry 20 Peck mm 1.5 Speed 356
Do you have any info re progressive reduction of feed rate?
It would seem sensible to reduce it in line with RPM or you are actually asking the drill to do more work per rev than previously.
What do you think?
regards
Melee
As I said, I reduce feedrate by 10% for each drill diameter in depth beyond 3, just as I do for peck depth. So, chipload actually decreases as you go deeper, since RPM is only decreasing at 5% per diameter. If you come up with any refinements on this, I'd love to hear about it. I've been unable to do much testing, due to electronic problems with my machine, awaiting some parts....
Regards,
Ray L.
