Announcement

Collapse
No announcement yet.

How do diamond coated edges help?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • How do diamond coated edges help?

    I wonder if diamond coated edges on drill bits and end mills really help make the cutting edges more durable? I guess they must,but how is it that the diamonds are not quickly eliminated from the tiny,sharp cutting edges? I can't see how they can stay put right on the cutting edges.

  • #2
    It acts as a lubricant. Diamonds aren't particularly strong since diamond is a cubic crystalline array and has shear planes in all three axes. Not much sticks to it though. It is also about the best conductor of heat there is with a thermal conductivity around five times better than pure silver. I don't imagine it actually does much for the cutting edge but it should help the swarf move up the flutes instead of packing.
    Free software for calculating bolt circles and similar: Click Here

    Comment


    • #3
      Originally posted by gwilson
      I wonder if diamond coated edges on drill bits and end mills really help make the cutting edges more durable? I guess they must,but how is it that the diamonds are not quickly eliminated from the tiny,sharp cutting edges? I can't see how they can stay put right on the cutting edges.
      Not sure how familiar you are with the process of diamond coating, but its not like they are gluing little chips of diamonds onto the substrate, they are "grown/plated" there using high temperatures in a vacuum. Basically a similar method to applying titaniam nitride coatings. My wife has a Master's in Materials Science From U of Florida and her thesis dealt with thin film diamond coatings. Some of the processes and Patents she worked on are used for applying diamond to optics (for scratch resistance)and as capacitors in chips. Kinda funny that I had to repeatedly explain Ohm's law to her... Not related, but one result of her thesis was what was thought to be the largest diamond in the world at the time (20yrs ago). It was a little over 8" in diameter and 1-2 microns thick grown on a stainless steel substrate, if I remember correctly.
      Greg

      Comment


      • #4
        Originally posted by Evan
        It acts as a lubricant. Diamonds aren't particularly strong since diamond is a cubic crystalline array and has shear planes in all three axes. Not much sticks to it though. It is also about the best conductor of heat there is with a thermal conductivity around five times better than pure silver. I don't imagine it actually does much for the cutting edge but it should help the swarf move up the flutes instead of packing.
        They are even making heat sink compound out of diamond powder because of the high thermal conductivity. I think I saw on Hackaday how to make your own. Lap your heatsink and paste at the same time!

        Comment


        • #5
          Is it still just a lubricant when applied as a film? I am,of course,familiar with plated wheels and sharpening stones. Didn't know about diamond optics coatings. They must be very small diamonds,or is the coating on an end mill a single crystal?

          Comment


          • #6
            It isn't crystaline at all but is what they call a "diamond like" amorphous carbon coating.

            Here is the full story from Sandia National Lab.

            http://www.sandia.gov/media/diamond.htm
            Free software for calculating bolt circles and similar: Click Here

            Comment


            • #7
              Diamond coated houses! Amazing,and very maintenance free.

              Comment


              • #8
                Most of the drills and end mills that you see have a coating of TiN or AITiN or maybe CBN(a bunch of other coatings as well). I don't think I've ever seen a truly diamond coated drill or end mill.

                It's my opinion that it's the hardness(wear resistance) that counts more than lubricity, although lubricity does count.

                Here's another site that is informative.

                http://www.harveytool.com/technical/coatings.php
                Last edited by drof34; 03-09-2010, 11:18 AM.

                Comment

                Working...
                X