Drill Speed for PCB

Discussion in 'General Electronics Chat' started by Return, Jan 17, 2013.

  1. Return

    Thread Starter New Member

    Jan 5, 2013
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    I'm using the Dremel drill press despite its awful reviews mine seems to be fine after tightening everything. What speed would be best with carbide bits? Would 35k work?
     
  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    I think that at 35k the bit would overheat in no time, but the "right" speed depends on the bit size you´re using.
     
  3. Return

    Thread Starter New Member

    Jan 5, 2013
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    I'm using a 0.7mm bit.
     
  4. gerty

    AAC Fanatic!

    Aug 30, 2007
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    And if it's sharp or not..
     
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    PCB drills typically run at like 25K RPM min (and way up to 100K to 200k for microvias).. 35K should be just fine..
     
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  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Technically a really small diameter drill should run at really high speeds like 25-35k.

    BUT, based on my Dremel experience, the Dremel buzzes really bad at high RPM, and that shakes the tiny drill around and causes other problems like really irritating noise and reduced brushes and bearings life, ozone you breathe in from the brush arcing etc etc.

    Personally I drill with a small drill stand for stability, and fairly low RPM maybe 10-15k. It takes a fraction longer to drill each hole but everything else is much better.
     
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  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Valid points.. The runout/bearing fit/finish on Dremels is horrible (but to be expected for the cost)
    Its not like you need to ensure the longest life out of these bits.. This isn't a professional application and as such could really be done by an old style "egg beater" drill and still be suitable..
     
  8. Metalmann

    Active Member

    Dec 8, 2012
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    Yes, vibration, or "Chatter"; is one of the worst enemy of any cutting tool.

    Dremel should use better quality, High Speed, bearings. It wouldn't add that much to the consumer price.

    And I think people would still buy Dremel.
     
  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    The balance of the Dremel is pretty bad, which is a big reason for the shakes, combined with a flexy plastic casing.

    My PCB drill press now has a small DC motor drill on it, one of the little "Supatool" types, normally 12v but I run it from a variable DC PSU and adjust the PSU voltage to find a nice quiet speed not on a mechanical resonance. It's very queit, energy efficient and only takes a second or two on each hole even though its underspeed.
     
  10. mhutchie1

    New Member

    Jan 21, 2013
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    I have been looking for the right speed for PCB drilling, and never got it right. I will have to give it another go at 25K! Thanks
     
  11. chrisw1990

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    Oct 22, 2011
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  12. Metalmann

    Active Member

    Dec 8, 2012
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    Carbide is always better for PCB boards, due to the abrasiveness/toughness of fiberglass materials.

    The main enemy of Carbide is shock. Avoid dropping those bits like the plague.;)
    Too many RPMs dull the outer bit cutting edges, or will burn them up; to the point where they can't be re-sharpened.

    If you'll be doing hundreds or thousands of holes, use Carbide bits.

    Carbide drill sizing:

    http://www.carbidedepot.com/formulas-drillsize.htm

    Speed and Feed Charts:

    http://www.guhring.com/Tech/SpeedFeed/
     
  13. Metalmann

    Active Member

    Dec 8, 2012
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    Another bit (Pun), of info on small PCB bits from Wiki:

    PCB through-hole drill bits

    "A great many holes with small diameters of about 1 mm or less must be drilled in printed circuit boards (PCBs) used by electronic equipment with through-hole components.

    Most PCBs are made of highly abrasive fiberglass, which quickly wears steel bits, especially given the hundreds or thousands of holes on most circuit boards.
    To solve this problem, solid tungsten carbide twist bits, which drill quickly through the board while providing a moderately long life, are almost always used.
    Carbide PCB bits are estimated to outlast high speed steel bits by a factor of ten or more. Other options sometimes used are diamond or diamond-coated bits.
    In industry, virtually all drilling is done by automated machines, and the bits are often automatically replaced by the equipment as they wear, as even solid carbide bits do not last long in constant use.
    PCB bits, of narrow diameter, typically mount in a collet rather than a chuck, and come with standard-size shanks, often with pre-installed stops to set them at an exact depth every time when being automatically chucked by the equipment.
    Very high rotational speeds—30,000 to 100,000 RPM or even higher—are used; this translates to a reasonably fast linear speed of the cutting tip in these very small diameters.

    The high speed, small diameter, and the brittleness of the material, make the bits very subject to breaking, particularly if the angle of the bit to the workpiece changes at all, or the bit contacts any object.



    Drilling by hand is not practicable, and many general-purpose drilling machines designed for larger bits rotate too slowly and wobble too much to use carbide bits effectively."
     
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