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Fixing high quality surface finish

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  • Charles
    I may be about to face an issue where a precision air bearing I am dis-assembling has some flat disk shaped surfaces that are finished to about 1 micron.
    Message 1 of 12 , Jun 27, 2012
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      I may be about to face an issue where a precision air bearing I am dis-assembling has some flat disk shaped surfaces that are finished to about 1 micron.

      Something may have put some scored lines, raised ridges, or whatever on these surfaces (which normally run only a few microns apart on a cushion of air).

      Any suggestions for a way to manually remove any high spots on a surface finish like this?

      Chuck K.
    • gerry waclawiak
      Hi Chuck, possibly a top quality diamond or ceramic whetstone might be flat enough (I m thinking DMT or Spyderco) and fine enough to lap the surfaces. Both
      Message 2 of 12 , Jun 28, 2012
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        Hi Chuck,

        possibly a top quality diamond or ceramic whetstone might be flat enough (I'm thinking DMT or Spyderco) and fine enough to lap the surfaces. Both manufacturers claim their stones are very flat but I cant seem to find any figures.

        I do have a set of Spyderco bench whetstones that I use to keep my woodworking tools in trim and the superfine is just that and very flat.

        I make model steam locos and the cylinder valves are basically flat plates and after prolonged use can get scored. I now routinely use the stones to lap and restore new and old valves. They can be done to a mirror finish which might be sufficient for what you need.

        I believe you can go even finer by using diamond lapping paste but I have no experience of those products.

        Gerry W
        Leeds UK





        To: GrizHFMinimill@yahoogroups.com
        From: ckinzer@...
        Date: Wed, 27 Jun 2012 22:26:10 +0000
        Subject: [GrizHFMinimill] Fixing high quality surface finish

         
        I may be about to face an issue where a precision air bearing I am dis-assembling has some flat disk shaped surfaces that are finished to about 1 micron.

        Something may have put some scored lines, raised ridges, or whatever on these surfaces (which normally run only a few microns apart on a cushion of air).

        Any suggestions for a way to manually remove any high spots on a surface finish like this?

        Chuck K.


      • Bill Williams
        ... I am with Gerry on this. You need a very fine and very flat diamond lap! I cannot think where they might be found but I suspect that they exist! Bill
        Message 3 of 12 , Jun 28, 2012
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          Charles wrote:
          > I may be about to face an issue where a precision air bearing I am
          > dis-assembling has some flat disk shaped surfaces that are finished
          > to about 1 micron.
          >
          > Something may have put some scored lines, raised ridges, or whatever
          > on these surfaces (which normally run only a few microns apart on a
          > cushion of air).
          >
          > Any suggestions for a way to manually remove any high spots on a
          > surface finish like this?
          >
          > Chuck K.

          I am with Gerry on this. You need a very fine and very flat diamond
          lap! I cannot think where they might be found but I suspect
          that they exist! Bill
        • dave_mucha
          I fear there is no way to do this at home. what looks like a bit of a mark will be like the Grand Canyon to the air spindle. anything you do to the surface,
          Message 4 of 12 , Jun 28, 2012
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            I fear there is no way to do this at home. what looks like a bit of a mark will be like the Grand Canyon to the air spindle.

            anything you do to the surface, even touch it with oily fingers will put the part way out of spec.

            Trying to remove anything from the surface that touches the surface will alter the geometry. if you see the results of your work on the bearing, you have made a huge change.

            look up the length of a micron. now, figure a way to alter the surface by less than that.

            Dave




            --- In GrizHFMinimill@yahoogroups.com, "Charles" <ckinzer@...> wrote:
            >
            > I may be about to face an issue where a precision air bearing I am dis-assembling has some flat disk shaped surfaces that are finished to about 1 micron.
            >
            > Something may have put some scored lines, raised ridges, or whatever on these surfaces (which normally run only a few microns apart on a cushion of air).
            >
            > Any suggestions for a way to manually remove any high spots on a surface finish like this?
            >
            > Chuck K.
            >
          • ckinzer@att.net
            I work at a place where we make precision grinding/polishing equipment for the semiconductor industry and beyond. I actually have a lot of acquaintence with
            Message 5 of 12 , Jun 28, 2012
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              I work at a place where we make precision grinding/polishing equipment for the semiconductor industry and beyond.  I actually have a lot of acquaintence with ridiculously small dimensions for wafer flatness we measure in angstroms and such.  I sometimes combine what I do with my home shop with what I do at work.  As an example, I milled a test fixture out of a 3/4 inch block of aluminum to test some 10 micron full scale range proximity probes for stability.  You can warm a quarter in your hand and place on the thick piece of aluminum and watch the readings change from the heat transfer caused dimensional change.  We're dealing with nanometers at that level.
               
              It was one of the probes that got something torn across the face of it when in a bearing running at its normal distance of about 10 microns a rotating flying surface.  The surface might normally have a runout of up to 2.5 microns.  And our application could actually tolerate much more than that.  I believe the finish on that surface is claimed to be 4 microinches.
               
              Chuck K.
               
               
              ----- Original Message -----
              Sent: Thursday, June 28, 2012 5:13 PM
              Subject: [GrizHFMinimill] Re: Fixing high quality surface finish

               

              I fear there is no way to do this at home. what looks like a bit of a mark will be like the Grand Canyon to the air spindle.

              anything you do to the surface, even touch it with oily fingers will put the part way out of spec.

              Trying to remove anything from the surface that touches the surface will alter the geometry. if you see the results of your work on the bearing, you have made a huge change.

              look up the length of a micron. now, figure a way to alter the surface by less than that.

              Dave

              --- In GrizHFMinimill@yahoogroups.com, "Charles" <ckinzer@...> wrote:
              >
              > I may be about to face an issue where a precision air bearing I am dis-assembling has some flat disk shaped surfaces that are finished to about 1 micron.
              >
              > Something may have put some scored lines, raised ridges, or whatever on these surfaces (which normally run only a few microns apart on a cushion of air).
              >
              > Any suggestions for a way to manually remove any high spots on a surface finish like this?
              >
              > Chuck K.
              >

            • grant.fair@sympatico.ca
              Lee Valley sells 3M mylar sheets of 1/2 micron micro abrasive, and polyester sheets with .5 and .1 micron diamond micro abrasive. I have no idea if or how
              Message 6 of 12 , Jun 28, 2012
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                Lee Valley sells 3M mylar sheets of 1/2 micron micro abrasive, and polyester sheets with .5 and .1 micron diamond micro abrasive.

                I have no idea if or how these might help you.

                Grant

                --- In GrizHFMinimill@yahoogroups.com, "Charles" <ckinzer@...> wrote:
                >
                > I may be about to face an issue where a precision air bearing I am dis-assembling has some flat disk shaped surfaces that are finished to about 1 micron.
                >
                > Something may have put some scored lines, raised ridges, or whatever on these surfaces (which normally run only a few microns apart on a cushion of air).
                >
                > Any suggestions for a way to manually remove any high spots on a surface finish like this?
                >
                > Chuck K.
                >
              • dave_mucha
                I know nothing about prox switches, but that type of sensitivity would be insane for the home cnc industry. are those krazy expensive ? Dave
                Message 7 of 12 , Jun 29, 2012
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                  I know nothing about prox switches, but that type of sensitivity would be insane for the home cnc industry.

                  are those krazy expensive ?

                  Dave

                  --- In GrizHFMinimill@yahoogroups.com, <ckinzer@...> wrote:
                  >
                  > I work at a place where we make precision grinding/polishing equipment for the semiconductor industry and beyond. I actually have a lot of acquaintence with ridiculously small dimensions for wafer flatness we measure in angstroms and such. I sometimes combine what I do with my home shop with what I do at work. As an example, I milled a test fixture out of a 3/4 inch block of aluminum to test some 10 micron full scale range proximity probes for stability. You can warm a quarter in your hand and place on the thick piece of aluminum and watch the readings change from the heat transfer caused dimensional change. We're dealing with nanometers at that level.
                  >
                  > It was one of the probes that got something torn across the face of it when in a bearing running at its normal distance of about 10 microns a rotating flying surface. The surface might normally have a runout of up to 2.5 microns. And our application could actually tolerate much more than that. I believe the finish on that surface is claimed to be 4 microinches.
                  >
                  > Chuck K.
                  >
                  >
                  > ----- Original Message -----
                  > From: dave_mucha
                  > To: GrizHFMinimill@yahoogroups.com
                  > Sent: Thursday, June 28, 2012 5:13 PM
                  > Subject: [GrizHFMinimill] Re: Fixing high quality surface finish
                  >
                  >
                  >
                  > I fear there is no way to do this at home. what looks like a bit of a mark will be like the Grand Canyon to the air spindle.
                  >
                  > anything you do to the surface, even touch it with oily fingers will put the part way out of spec.
                  >
                  > Trying to remove anything from the surface that touches the surface will alter the geometry. if you see the results of your work on the bearing, you have made a huge change.
                  >
                  > look up the length of a micron. now, figure a way to alter the surface by less than that.
                  >
                  > Dave
                  >
                  > --- In GrizHFMinimill@yahoogroups.com, "Charles" <ckinzer@> wrote:
                  > >
                  > > I may be about to face an issue where a precision air bearing I am dis-assembling has some flat disk shaped surfaces that are finished to about 1 micron.
                  > >
                  > > Something may have put some scored lines, raised ridges, or whatever on these surfaces (which normally run only a few microns apart on a cushion of air).
                  > >
                  > > Any suggestions for a way to manually remove any high spots on a surface finish like this?
                  > >
                  > > Chuck K.
                  > >
                  >
                • Charles Kinzer
                  Yes.  Nicer the nice.  Higher the price.  Sensor is about $1100.  Its very special amplifier is about $2000.  There is a huge amount of hidden technology
                  Message 8 of 12 , Jun 29, 2012
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                    Yes.  Nicer the nice.  Higher the price.  Sensor is about $1100.  Its very special amplifier is about $2000.  There is a huge amount of hidden technology in these things.  They are not like garden variety prox switches.
                     
                    Chuck K.


                    From: dave_mucha <dave_mucha@...>
                    To: GrizHFMinimill@yahoogroups.com
                    Sent: Fri, June 29, 2012 3:29:11 AM
                    Subject: [GrizHFMinimill] Re: Fixing high quality surface finish

                     

                    I know nothing about prox switches, but that type of sensitivity would be insane for the home cnc industry.

                    are those krazy expensive ?

                    Dave

                    --- In GrizHFMinimill@yahoogroups.com, <ckinzer@...> wrote:
                    >
                    > I work at a place where we make precision grinding/polishing equipment for the semiconductor industry and beyond. I actually have a lot of acquaintence with ridiculously small dimensions for wafer flatness we measure in angstroms and such. I sometimes combine what I do with my home shop with what I do at work. As an example, I milled a test fixture out of a 3/4 inch block of aluminum to test some 10 micron full scale range proximity probes for stability. You can warm a quarter in your hand and place on the thick piece of aluminum and watch the readings change from the heat transfer caused dimensional change. We're dealing with nanometers at that level.
                    >
                    > It was one of the probes that got something torn across the face of it when in a bearing running at its normal distance of about 10 microns a rotating flying surface. The surface might normally have a runout of up to 2.5 microns. And our application could actually tolerate much more than that. I believe the finish on that surface is claimed to be 4 microinches.
                    >
                    > Chuck K.
                    >
                    >
                    > ----- Original Message -----
                    > From: dave_mucha
                    > To: GrizHFMinimill@yahoogroups.com
                    > Sent: Thursday, June 28, 2012 5:13 PM
                    > Subject: [GrizHFMinimill] Re: Fixing high quality surface finish
                    >
                    >
                    >
                    > I fear there is no way to do this at home. what looks like a bit of a mark will be like the Grand Canyon to the air spindle.
                    >
                    > anything you do to the surface, even touch it with oily fingers will put the part way out of spec.
                    >
                    > Trying to remove anything from the surface that touches the surface will alter the geometry. if you see the results of your work on the bearing, you have made a huge change.
                    >
                    > look up the length of a micron. now, figure a way to alter the surface by less than that.
                    >
                    > Dave
                    >
                    > --- In GrizHFMinimill@yahoogroups.com, "Charles" <ckinzer@> wrote:
                    > >
                    > > I may be about to face an issue where a precision air bearing I am dis-assembling has some flat disk shaped surfaces that are finished to about 1 micron.
                    > >
                    > > Something may have put some scored lines, raised ridges, or whatever on these surfaces (which normally run only a few microns apart on a cushion of air).
                    > >
                    > > Any suggestions for a way to manually remove any high spots on a surface finish like this?
                    > >
                    > > Chuck K.
                    > >
                    >

                  • Charles
                    The nicer the nice. The higher the price. Sensor is about $1100. Its very special amplifier is about $2000. These things have a huge amount of technology
                    Message 9 of 12 , Jun 29, 2012
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                      The nicer the nice. The higher the price. Sensor is about $1100. Its very special amplifier is about $2000. These things have a huge amount of technology in them. They are not like garden variety prox sensors.

                      Chuck K.

                      --- In GrizHFMinimill@yahoogroups.com, "dave_mucha" <dave_mucha@...> wrote:
                      >
                      > I know nothing about prox switches, but that type of sensitivity would be insane for the home cnc industry.
                      >
                      > are those krazy expensive ?
                      >
                      > Dave
                      >
                      > --- In GrizHFMinimill@yahoogroups.com, <ckinzer@> wrote:
                      > >
                      > > I work at a place where we make precision grinding/polishing equipment for the semiconductor industry and beyond. I actually have a lot of acquaintence with ridiculously small dimensions for wafer flatness we measure in angstroms and such. I sometimes combine what I do with my home shop with what I do at work. As an example, I milled a test fixture out of a 3/4 inch block of aluminum to test some 10 micron full scale range proximity probes for stability. You can warm a quarter in your hand and place on the thick piece of aluminum and watch the readings change from the heat transfer caused dimensional change. We're dealing with nanometers at that level.
                      > >
                      > > It was one of the probes that got something torn across the face of it when in a bearing running at its normal distance of about 10 microns a rotating flying surface. The surface might normally have a runout of up to 2.5 microns. And our application could actually tolerate much more than that. I believe the finish on that surface is claimed to be 4 microinches.
                      > >
                      > > Chuck K.
                      > >
                      > >
                      > > ----- Original Message -----
                      > > From: dave_mucha
                      > > To: GrizHFMinimill@yahoogroups.com
                      > > Sent: Thursday, June 28, 2012 5:13 PM
                      > > Subject: [GrizHFMinimill] Re: Fixing high quality surface finish
                      > >
                      > >
                      > >
                      > > I fear there is no way to do this at home. what looks like a bit of a mark will be like the Grand Canyon to the air spindle.
                      > >
                      > > anything you do to the surface, even touch it with oily fingers will put the part way out of spec.
                      > >
                      > > Trying to remove anything from the surface that touches the surface will alter the geometry. if you see the results of your work on the bearing, you have made a huge change.
                      > >
                      > > look up the length of a micron. now, figure a way to alter the surface by less than that.
                      > >
                      > > Dave
                      > >
                      > > --- In GrizHFMinimill@yahoogroups.com, "Charles" <ckinzer@> wrote:
                      > > >
                      > > > I may be about to face an issue where a precision air bearing I am dis-assembling has some flat disk shaped surfaces that are finished to about 1 micron.
                      > > >
                      > > > Something may have put some scored lines, raised ridges, or whatever on these surfaces (which normally run only a few microns apart on a cushion of air).
                      > > >
                      > > > Any suggestions for a way to manually remove any high spots on a surface finish like this?
                      > > >
                      > > > Chuck K.
                      > > >
                      > >
                      >
                    • dave_mucha
                      sensing into the angstrom range is beyond comprehension for home CNC units. of course the math leads some to think they can. I use simple micro-switches and
                      Message 10 of 12 , Jun 29, 2012
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                        sensing into the angstrom range is beyond comprehension for home CNC units. of course the math leads some to think they can.

                        I use simple micro-switches and find them very repeatable for my needs.

                        Dave

                        --- In GrizHFMinimill@yahoogroups.com, "Charles" <ckinzer@...> wrote:
                        >
                        > The nicer the nice. The higher the price. Sensor is about $1100. Its very special amplifier is about $2000. These things have a huge amount of technology in them. They are not like garden variety prox sensors.
                        >
                        > Chuck K.
                        >
                        > --- In GrizHFMinimill@yahoogroups.com, "dave_mucha" <dave_mucha@> wrote:
                        > >
                        > > I know nothing about prox switches, but that type of sensitivity would be insane for the home cnc industry.
                        > >
                        > > are those krazy expensive ?
                        > >
                        > > Dave
                        > >
                        > > --- In GrizHFMinimill@yahoogroups.com, <ckinzer@> wrote:
                        > > >
                        > > > I work at a place where we make precision grinding/polishing equipment for the semiconductor industry and beyond. I actually have a lot of acquaintence with ridiculously small dimensions for wafer flatness we measure in angstroms and such. I sometimes combine what I do with my home shop with what I do at work. As an example, I milled a test fixture out of a 3/4 inch block of aluminum to test some 10 micron full scale range proximity probes for stability. You can warm a quarter in your hand and place on the thick piece of aluminum and watch the readings change from the heat transfer caused dimensional change. We're dealing with nanometers at that level.
                        > > >
                        > > > It was one of the probes that got something torn across the face of it when in a bearing running at its normal distance of about 10 microns a rotating flying surface. The surface might normally have a runout of up to 2.5 microns. And our application could actually tolerate much more than that. I believe the finish on that surface is claimed to be 4 microinches.
                        > > >
                        > > > Chuck K.
                        > > >
                        > > >
                        > > > ----- Original Message -----
                        > > > From: dave_mucha
                        > > > To: GrizHFMinimill@yahoogroups.com
                        > > > Sent: Thursday, June 28, 2012 5:13 PM
                        > > > Subject: [GrizHFMinimill] Re: Fixing high quality surface finish
                        > > >
                        > > >
                        > > >
                        > > > I fear there is no way to do this at home. what looks like a bit of a mark will be like the Grand Canyon to the air spindle.
                        > > >
                        > > > anything you do to the surface, even touch it with oily fingers will put the part way out of spec.
                        > > >
                        > > > Trying to remove anything from the surface that touches the surface will alter the geometry. if you see the results of your work on the bearing, you have made a huge change.
                        > > >
                        > > > look up the length of a micron. now, figure a way to alter the surface by less than that.
                        > > >
                        > > > Dave
                        > > >
                        > > > --- In GrizHFMinimill@yahoogroups.com, "Charles" <ckinzer@> wrote:
                        > > > >
                        > > > > I may be about to face an issue where a precision air bearing I am dis-assembling has some flat disk shaped surfaces that are finished to about 1 micron.
                        > > > >
                        > > > > Something may have put some scored lines, raised ridges, or whatever on these surfaces (which normally run only a few microns apart on a cushion of air).
                        > > > >
                        > > > > Any suggestions for a way to manually remove any high spots on a surface finish like this?
                        > > > >
                        > > > > Chuck K.
                        > > > >
                        > > >
                        > >
                        >
                      • Bill Williams
                        ... Well if the thickness of these sheets was uniform to the same range then attaching a sheet to a really flat surface might allow lapping out the scratches!
                        Message 11 of 12 , Jun 29, 2012
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                          grant.fair@... wrote:
                          > Lee Valley sells 3M mylar sheets of 1/2 micron micro abrasive, and
                          > polyester sheets with .5 and .1 micron diamond micro abrasive.
                          >
                          > I have no idea if or how these might help you.
                          >
                          > Grant

                          Well if the thickness of these sheets was uniform to the same range
                          then attaching a sheet to a really flat surface might allow lapping out
                          the scratches! Or you might be able to use one scratched surface as the
                          backing to allow lapping the other!

                          Bill in Boulder; just guessing!
                        • Bill Williams
                          ... Years ago at Kaman Instrumentation I worked on developing one that would step across a silicon wafer in increments of four atoms! Thought that was a cute
                          Message 12 of 12 , Jun 29, 2012
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                            Charles Kinzer wrote:
                            >
                            >
                            > Yes. Nicer the nice. Higher the price. Sensor is about $1100. Its
                            > very special amplifier is about $2000. There is a huge amount of hidden
                            > technology in these things. They are not like garden variety prox switches.
                            >
                            > Chuck K.

                            Years ago at Kaman Instrumentation I worked on developing one that
                            would step across a silicon wafer in increments of four atoms! Thought
                            that was a cute thing to be doing! Bill in Boulder
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