Cylinder head circular runout question

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

  • Cylinder head circular runout question

    Help me out here. Im about to program this part. The area Im curious about is the part where I circled. As you can see, its an area behind the where the valve would seat, and it has a perpendicularity(back to the "plane",top surface,or -A-) and a circular runout callout. The way it works is Ill measure the corresponding valve guide as a cylinder, right? And measure this area I circled as a cylinder, albeit a short one, and dimension its circular runout back to the valve guide, right?

    head.jpg
    Last edited by Mike_B; 03-13-2013, 12:55 PM.
    Browne & Sharpe Global Advantage 12|22|10
    PCD 2012 MR1 CAD++

  • #2
    sounds logical to me, give er' a try ...................
    I AM the one who KNOCKS !

    Comment


    • #3
      Correct.

      Comment


      • #4
        Originally posted by DungT
        No, it’s not. Circular runout applies to each circular cross section; total runout applies over the entire length of a cylinder.

        Ah, remind me again what the symbols for circular runout and total runout are again?

        And then go back and look at the callout.

        And then slow down, Dung. Lay off that good coffee for a bit. Chill, Winston.

        Comment


        • #5
          What is Datum [-E-]? Is it a diameter or a surface? Too many designers/engineers call for circular runout on parts that are checked "Statically" (stationary) on the CMM. Runout is a "Dynamic" (rotational) check, so even though the software will let you report runout, it really isn't an accurate representation. If Datum [-E-] is a diameter, report it as position. If it is a surface, report it as perpendicularity.
          Marty Dobson
          Director of Quality
          http://www.linkedin.com/in/mjdobson

          PC-DMIS CAD V4.2 MR1 & V2011
          PH10MQ
          TP200

          Comment


          • #6
            Originally posted by DungT
            One arrow = Circular runout
            Double arrow = Total runout
            Am I missing something?
            You're missing that his callout specifies circular runout.

            Comment


            • #7
              Originally posted by DungT
              No I did not.
              Checking circular runout of a cylinder with v4.0 will give you total runout result.
              Are you stuck with 4.0? Oh man.

              I will test this in 2013 release candidate.

              Comment


              • #8
                So on this drawing, is it asking for total or circular? I have just finished up measureing everything as cylinders...
                Browne & Sharpe Global Advantage 12|22|10
                PCD 2012 MR1 CAD++

                Comment


                • #9
                  Just so you know, a cmm cannot, does not, nor have they ever been able to measure runout.
                  Circular, total or otherwise.
                  They report relative position of the centroid, nothing more.
                  To even get somewhere close you have to make sure your calculation method of the circle/cylinder is correct.
                  (NOT least squares, max insc or min circ depending on the feature)
                  Runout is a dynamic check of the feature and cmm's dont work that way.
                  Just because the software symbol says runout doesnt mean its actually runout.
                  Roses are red
                  Violets are glorious
                  Don't try to sneak up
                  On Oscar Pistorius.

                  MIL-TFP-41C

                  3.7mr3, 2012mr1, 2013mr1

                  Comment


                  • #10
                    Thanks guys....
                    Browne & Sharpe Global Advantage 12|22|10
                    PCD 2012 MR1 CAD++

                    Comment


                    • #11
                      Originally posted by pwhitsa View Post
                      Just so you know, a cmm cannot, does not, nor have they ever been able to measure runout.
                      Circular, total or otherwise.
                      They report relative position of the centroid, nothing more.
                      To even get somewhere close you have to make sure your calculation method of the circle/cylinder is correct.
                      (NOT least squares, max insc or min circ depending on the feature)
                      Runout is a dynamic check of the feature and cmm's dont work that way.
                      Just because the software symbol says runout doesnt mean its actually runout.
                      Hammer....meet nail.

                      I'm really surprised to hear the lack of attention to detail in some of these replies
                      sigpic
                      Originally posted by Ironhoe
                      I got something under my sporran for you, take care of it and you got my vote.

                      Comment


                      • #12
                        DungT has been correct in his statements all along.

                        If you apply runout (single arrow) on a cylinder using PC-DMIS, the result will be total indicated runout.
                        If you apply total indicated runout (double arrows) on a cylinder the result will be total indicated runout.

                        The above applies if they haven't added a "featurecheck" where PC-DMIS cuts the cylinder in x cross-sections and applies
                        the single runout on each of them...

                        If you apply runout (single arrow) on a circle the result will be circular runout (a cross-section).
                        If you apply total indicated runout (double arrows) on a circle the result will be circular runout.

                        This is a pitfall and demands a seasoned operator (read: knows his GD&T and the CMM software) to be able to "see" stuff like this.

                        Of course, the same applies to axial runout. The way you measure the plane will affect the result, no matter if you choose circular runout
                        or total indicated runout - these will yield the same result. In order to "properly" measure axial (single) runout, you'd need to measure
                        the plane/points in a circular fashion - if you don't, you will be checking total indicated runout even if you chose the single arrow runout.

                        See the difference? The method of retrieving the toleranced feature is important here, regardless of your choice of runout.
                        Last edited by vpt.se; 03-14-2013, 07:57 AM.
                        PC-DMIS CAD++ 2o19 R1 SP11

                        Comment


                        • #13
                          Just remember that PC-DMIS will calculate runout with all measuring points you collect for the feature, nothing more, nothing less. It's up to you to collect them in the correct way.
                          AndersI
                          SW support - Hexagon Metrology Nordic AB

                          Comment


                          • #14
                            Yes, the truth can stand repeating.
                            AndersI
                            SW support - Hexagon Metrology Nordic AB

                            Comment


                            • #15
                              Just remember that PC-DMIS will calculate runout with all measuring points you collect for the feature, nothing more, nothing less. It's up to you to collect them in the correct way.
                              That's another way of saying it.
                              Last edited by vpt.se; 03-14-2013, 10:53 AM.
                              PC-DMIS CAD++ 2o19 R1 SP11

                              Comment

                              Related Topics

                              Collapse

                              Working...
                              X