Finally figured out Read Points...

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  • Finally figured out Read Points...

    Yay Me!

    For those of you that have been fortunate enough to not have notice my posts, I'm completely Self-Taught, and I'm running a Global Performance 12-15-10 with 2018 R2, a B&S 10-12-10 with the same system, and an old Sheffield Discovery D12 with 2017 R1.

    The main problem I have is not knowing what I don't know, so the purpose of this, I suppose, is to throw out there what I figured out (finally) today, and hopefully spare somebody else the embarrassment of asking what I never got around to...

    As with every program I write (no CAD. Strictly touching off the part and correcting the program to reflect the print) I insert a Report Command, Comment to instruct the operator how to load the part on the CMM surface plate. We've got stops screwed into the table, and often use them, and sometimes we take manual hits to get an initial alignment (only to realign when we have more precise data). That's all well and good, but I've been wanting to figure out Read Points for a while. Give me a rough orientation on the table, move the ruby to a specific point in relation to a feature on the part, and pull the trigger. Here's what I've figured out:

    After the Report Command, Comment (which tells the operator where to place the ruby in relation to the part. Something like: "Orient part per print, roughly in center of table. Move Ruby to .1" above left corner of part nearest you"), Click "Insert", then "Feature", then Read Point. Ensure offsets are at 0,0,0. Click on "New Alignment". As you've only got one feature in the window, click on the Read Point, and hit Auto Align. Then switch it to DCC Mode, and touch off a small area on top of the part as a Z plane (I only touched off a small .15 X.15 area. 3 hits), insert a move point to clear the edge of the part and touch off the front of the part in much the same manner. Another move point, and then I can touch off a small area of the left side of the part, and now I've got 3 planes to create a line and a point. This gives me all I need for a rudimentary alignment. I leave my prehit generous for the time being, until I retouch off those same features (using a larger area) and realign using the more accurate data. From there, it's simply a matter of measuring the part as I would if it were fixtured on the table.

    (of course, at this point, there's much "cleaning up" of vectors, etc, anticipating the ideal part.)

    Please, you folks who have known this stuff for so long, have I got the basics down (of installing Read Points that is...)

    Oh, and just in case any of you were wondering: Yes. I did do a search for "Read Points". Do you know how many times the word "read" and the word "points" appear separately in these forums?

  • #2
    I make the center of a diameter on the part my readpoint. I use comment to tell (and show with screenshot) the operator which hole and to put the probe at the top of the diameter.
    I always transform my model to match that diameter (if I have one).
    I align readpoint X,Y,Z origin.
    Then I create 3 point circle and align X,Y,Z to circle.
    Then create base alignment with increased prehit/retract to completely find and orient the part.
    Then create my program alignment.

    There are multiple ways to do almost anything so if its working continue to use and you will find better ways as you grow.


    • #3
      Originally posted by Quality ish View Post

      Oh, and just in case any of you were wondering: Yes. I did do a search for "Read Points". Do you know how many times the word "read" and the word "points" appear separately in these forums?
      Are you going to keep us hanging or are you going to tell us? I believe this was the most important sentence in your paragraph. Kidding aside, good for you. keep it up.

      (In Memory of my Loving wife, "Ronda" who I lost March 7, 2016. I love you baby.)
      They say "Nobody's Perfect." I must be Nobody.


      • Quality ish
        Quality ish commented
        Editing a comment
        2.3 oodles.

    • #4
      If you load your part in the same place on the CMM surface plate, you don't have to do anything manually. Your goal should be to write your programs in such a way that operators never have to drive the machine manually. Here is what I would do if I were you:

      - Create a new program, MODE/MANUAL
      - Install the fixturing per your instructions, and your part. Make sure your fixturing is installed in the SAME place every time.
      - Manually measure your features and create an alignment.
      - Go to Insert>Alignment>Save and save the alignment. You have now created an external alignment.
      - In your main program, go to Insert>Alignment>Recall, and select the alignment you have created.

      Now you can just run in DCC mode and measure the features and create another alignment for fine tuning. As long as the fixturing is in the same place, you never have to remeasure the part manually, or use read points. If you have to move the fixturing, you go back to the alignment program you created and measure the part in the updated position.


      • #5
        Unfortunately, I'm not the only programmer for these units (and as many here can testify, while 2nd shifters generally have to be self reliant - as we have little to no infrastructure on 2nd- we are most definitely seen as second class citizens.

        I know more, and can do more, but it's completely disregarded by the powers that be. (Probably because I'm an uncompromising SOB who refuses to pass parts that don't conform to print.) As a result, the Production Mgr isn't a fan, but the higher echelon knows that when I say it's good, it's likely not coming back.
        Last edited by Quality ish; 07-04-2019, 12:06 AM.


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