Announcement

Collapse
No announcement yet.

DRO Questions.

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

  • DRO Questions.

    So, my DRO has ability to find Absolute Reference Point of Scale. REF Function. I've never used this.. but would like to. However, it has 3 modes, and doesn't explain the difference between them. REF, AB, LEF_AB

    Anyone know about this feature and know what those modes are, how their different and when to use which one?

    Thanks, Connor

  • #2
    What brand of DRO?????????????????
    The shortest distance between two points is a circle of infinite diameter.

    Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

    Southwestern Ontario. Canada

    Comment


    • #3
      Originally posted by loose nut View Post
      What brand of DRO?????????????????
      Chinese. From TPAC Tools https://www.tpactools.com/

      Link to manual - https://wiki.knoxmakers.org/images/0/06/Dro-manual.pdf

      Comment


      • #4
        I would have to ask, what brand too. My DRO's both lathe and mill have absolute and incremental functions. The reference part is determined by the scale and not the display, at least on my Acu Rite DRO on my mill. I use the home reference all the time as the vise back jaw is zeroed off of it.
        All the scales on my mill have home reference points. I have to move the scale travel about 1 1/2" and it will find the home ref.
        On my lathe the cross slide micro scale doesn't have the home ref. feature and I remember the guy I bought it from telling me that, so that's how I know this feature is built into the scale.

        JL.................

        Comment


        • #5
          Lathe or mill?
          The scale reference point on a lathe Z axis is fairly useless, do you know how long the next part is going to be?

          As a side note I do not trust them after they have been powered down for say a day or two.
          I once did an orderly shut of a 2 axis Bridgeport CNC lathe on a Friday afternoon. Returned on Monday morning and touched off the unfinished part from Friday and this is what I got, X should be .2XX" and Z should be +-.025", it is only a 15" X 30" machine.
          And yes it homed during boot up.
          Last edited by Bented; 02-24-2020, 09:04 PM.

          Comment


          • #6
            Originally posted by Bented View Post
            Lathe or mill?
            The scale reference point on a lathe Z axis is fairly useless, do you know how long the next part is going to be?

            As a side note I do not trust them after they have been powered down for say a day or two.
            I once did an orderly shut of a 2 axis Bridgeport CNC lathe on a Friday afternoon. Returned on Monday morning and touched off the unfinished part from Friday and this is what I got, X should be .2XX" and Z should be +-.025", it is only a 15" X 30" machine.
            And yes it homed during boot up.
            Well yes and no, There have been many times where I had to leave a part chucked up in my lathe overnight or for a day or so before I could get back to finishing it. It's nice to power up the DRO and find your reference point. But I do understand that once the part is removed the reference point is lost.

            JL............

            Comment


            • #7
              Originally posted by JoeLee View Post
              Well yes and no, There have been many times where I had to leave a part chucked up in my lathe overnight or for a day or so before I could get back to finishing it. It's nice to power up the DRO and find your reference point. But I do understand that once the part is removed the reference point is lost.

              JL............
              Exactly, this machine homes to limit switches on both axes when booted, I expect it to be off by the error in the switches but not 63" (-:

              Comment


              • #8
                Originally posted by JoeLee View Post
                I would have to ask, what brand too. My DRO's both lathe and mill have absolute and incremental functions. The reference part is determined by the scale and not the display, at least on my Acu Rite DRO on my mill. I use the home reference all the time as the vise back jaw is zeroed off of it.
                Thanks. It never occurred to me to make the corner of the vise 0,0. absolute. That just makes so much sense!

                Dan
                At the end of the project, there is a profound difference between spare parts and extra parts.

                Location: SF East Bay.

                Comment


                • #9
                  Originally posted by Bented View Post

                  Exactly, this machine homes to limit switches on both axes when booted, I expect it to be off by the error in the switches but not 63" (-:
                  No limit switchs here. The home reference positions are built into the encoding of the scale. Some of the Acu Rite scales have this feature in some of them dont.

                  JL.....

                  Comment


                  • #10
                    This is for the mill. Standard glass scales with a single Reference point from what I can tell.

                    Comment


                    • #11
                      I believe you are talking about the reference point on the scales. This allows you to recover the reference point if you have a power outage or an axis is moved with the DRO off. On my machine to use this you select Ref then it will ask you to select which axis. The display for that axis will begin to flash. Then you move that axis past the axis point on the scale, which on my DRO is near the center of the scale, and back again until the display starts to read normally and follow the movement of that axis. On mine this only works in one direction. You would have to find out which way to move first. If you miss and get it wrong just go all the way to near the other end and then back again. Your manual looks to be clear on this.
                      Larry - west coast of Canada

                      Comment


                      • #12
                        Originally posted by Cuttings View Post
                        I believe you are talking about the reference point on the scales. This allows you to recover the reference point if you have a power outage or an axis is moved with the DRO off. On my machine to use this you select Ref then it will ask you to select which axis. The display for that axis will begin to flash. Then you move that axis past the axis point on the scale, which on my DRO is near the center of the scale, and back again until the display starts to read normally and follow the movement of that axis. On mine this only works in one direction. You would have to find out which way to move first. If you miss and get it wrong just go all the way to near the other end and then back again. Your manual looks to be clear on this.
                        Yea, I was just wondering what the 3 modes where.. Ref, AB, and LEF_AB It makes no mention when to use which one or why.

                        Comment


                        • #13
                          Originally posted by Connor View Post

                          Yea, I was just wondering what the 3 modes where.. Ref, AB, and LEF_AB It makes no mention when to use which one or why.
                          Pure guess but:
                          Ref = set zero to previously programmed reference location ie 1.3454 inches from the absolute reference
                          AB = sets zero to absolute reference marker at the end of the scale
                          LEF_AB = sets zero to absolute reference marker at the left end of the scale
                          ?

                          Comment


                          • #14
                            Originally posted by Bented View Post

                            Exactly, this machine homes to limit switches on both axes when booted, I expect it to be off by the error in the switches but not 63" (-:
                            Any movement of the scale before the DRO fully boots up will cause error. If the lathe carriage moved 63" between the time you shut it down and when the DRO booted up again, that's the error you'll get. If the machine homes to limit switches when turned on, maybe the DRO isn't fully booted up before it does that? Assuming your DRO does not have an "absolute" reading function like some calipers.

                            Then again, it's possible your DRO head resets to some default value when it boots up again?

                            Comment


                            • #15
                              Originally posted by Yondering View Post

                              Any movement of the scale before the DRO fully boots up will cause error. If the lathe carriage moved 63" between the time you shut it down and when the DRO booted up again, that's the error you'll get. If the machine homes to limit switches when turned on, maybe the DRO isn't fully booted up before it does that? Assuming your DRO does not have an "absolute" reading function like some calipers.

                              Then again, it's possible your DRO head resets to some default value when it boots up again?
                              Lathe will not move 63" unless it moves 30" past the head stock or the tail stock end of the lead screw, it is a CNC machine that moves each axis to a home switch when booting and can not be manually moved during this process.

                              Comment

                              Working...
                              X